Publications

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01Juil/19

Yvan-Charvet L, Ng LG

Trends Immunol. 2019 Jul;40(7):598-612

Abstract

PMID: 31256783

Granulopoiesis is part of the hematopoietic hierarchic architecture, where hematopoietic stem cells give rise to highly proliferative multipotent and lineage-committed granulocytic progenitor cells that differentiate into unipotent neutrophil progenitors. Given their short lifespan, neutrophils are rapidly cleared from circulation through specialized efferocytic macrophages. Together with an intrinsic clock, these processes contribute to circadian fluctuations, preserving self-tolerance and protection against invading pathogens. However, metabolic perturbation of granulopoiesis and neutrophil homeostasis can result in low-grade chronic inflammation, as observed with aging. During acute pathogenic infections, hematopoiesis can also be switched into emergency mode, which has been recently associated with significant neutrophil functional heterogeneity. This review focuses on a new reassessment of regulatory mechanisms governing neutrophil production, life-cycle, and diversity in health and disease.

01Juil/19

Yvan-Charvet L, Bonacina F, Guinamard RR, Norata GD

Cardiovasc. Res. 2019 Jul;115(9):1393-1407

Abstract

PMID: 31095280

Inflammation represents the driving feature of many diseases, including atherosclerosis, cancer, autoimmunity and infections. It is now established that metabolic processes shape a proper immune response and within this context the alteration in cellular cholesterol homeostasis has emerged as a culprit of many metabolic abnormalities observed in chronic inflammatory diseases. Cholesterol accumulation supports the inflammatory response of myeloid cells (i.e. augmentation of toll-like receptor signalling, inflammasome activation, and production of monocytes and neutrophils) which is beneficial in the response to infections, but worsens diseases associated with chronic metabolic inflammation including atherosclerosis. In addition to the innate immune system, cells of adaptive immunity, upon activation, have also been shown to undergo a reprogramming of cellular cholesterol metabolism, which results in the amplification of inflammatory responses. Aim of this review is to discuss (i) the molecular mechanisms linking cellular cholesterol metabolism to specific immune functions; (ii) how cellular cholesterol accumulation sustains chronic inflammatory diseases such as atherosclerosis; (iii) the immunometabolic profile of patients with defects of genes affecting cholesterol metabolism including familial hypercholesterolaemia, cholesteryl ester storage disease, Niemann-Pick type C, and immunoglobulin D syndrome/mevalonate kinase deficiency. Available data indicate that cholesterol immunometabolism plays a key role in directing immune cells function and set the stage for investigating the repurposing of existing ‘metabolic’ drugs to modulate the immune response.

01Juil/19

Kaminski L, Torrino S, Dufies M, Djabari Z, Haider R, Roustan FR, Jaune E, Laurent K, Nottet N, Michiels JF, Gesson M, Rocchi S, Mazure NM, Durand M, Tanti JF, Ambrosetti D, Clavel S, Ben-Sahra I, Bost F

Cancer Res. 2019 Jul;79(13):3268-3280

Abstract

PMID: 31064849

Although tumorigenesis is dependent on the reprogramming of cellular metabolism, the metabolic pathways engaged in the formation of metastases remain largely unknown. The transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) plays a pleiotropic role in the control of cancer cell metabolism and has been associated with a good prognosis in prostate cancer. Here, we show that PGC1α represses the metastatic properties of prostate cancer cells via modulation of the polyamine biosynthesis pathway. Mechanistically, PGC1α inhibits the expression of c-MYC and ornithine decarboxylase 1 (ODC1), the rate-limiting enzyme for polyamine synthesis. Analysis of metastases and clinical data from patients with prostate cancer support the proposition that the PGC1α/c-MYC/ODC1 axis regulates polyamine biosynthesis and prostate cancer aggressiveness. In conclusion, downregulation of PGC1α renders prostate cancer cells dependent on polyamine to promote metastasis. SIGNIFICANCE: These findings show that a major regulator of mitochondrial metabolism controls polyamine synthesis and prostate cancer aggressiveness, with potential applications in therapy and identification of new biomarkers.

01Juil/19

Lareyre F, Clément M, Moratal C, Loyer X, Jean-Baptiste E, Hassen-Khodja R, Chinetti G, Mallat Z, Raffort J

Biochimie 2019 Jul;162:1-7

Abstract

PMID: 30922869

OBJECTIVES: The potential implication of micro-RNAs (miRs) in the negative association between diabetes and abdominal aortic aneurysm (AAA) has so far never been addressed. The aim of this study was to compare miR expression between diabetic and non-diabetic patients with AAA.

METHODS: Ten diabetic patients were prospectively included and compared to 10 age- and sex-matched non-diabetic patients with infrarenal AAA. A profiling analysis of 752 human miRs was performed from peripheral blood mononuclear cells (PBMCs) using miRCURY LNA Universal RT microRNA PCR (Exiqon- Qiagen). miR that showed significant differential expression (P < 0.05) were selected and further analyzed in the entire cohort in sera, plasma and aneurysmal aortic tissues.

RESULTS: Four miRs were significantly differentially expressed in PBMCs of diabetic patients compared to non-diabetics: 3 were upregulated (miR-144-3p, 20a-5p and 188-3p) and 1 downregulated (miR-548k). miR-144-3p and miR-548k were also increased in aneurysmal tissue and miR-20a-5p was increased in serum. The expression of miR-20a-5p in PBMCs was correlated with fructosamine concentration (r = 0.62, p = 0.006).

CONCLUSIONS: Even if further studies are required to determine their direct role in AAA, these miRs could represent interesting new targets.

28Juin/19

Ivanov S, Gallerand A, Gros M, Stunault MI, Merlin J, Vaillant N, Yvan-Charvet L, Guinamard RR

Eur. J. Immunol. 2019 Jun;

Abstract

PMID: 31251389

Macrophages play a central role during infection, inflammation and tissue homeostasis maintenance. Macrophages have been identified in all organs and their core transcriptomic signature and functions differ from one tissue to another. Interestingly, macrophages have also been identified in the peritoneal cavity and these cells have been extensively used as a model for phagocytosis, efferocytosis and polarization. Peritoneal macrophages are involved in B-cell IgA production, control of inflammation and wound healing following thermal-induced liver surface injury. These cells presumably require and interact with the omentum, where milky spot stromal cells have been proposed to secrete CSF1 (colony stimulating factor 1). Peritoneal macrophages depend on CSF1 for their generation and survival, but the identity of CSF1 producing cells inside the large peritoneal cavity remains unknown. Here we investigated peritoneal macrophage localization and their interaction with mesothelial cells, the major cell type predicted to secrete CSF1. Our data revealed that mesothelial cells produce membrane bound and secreted CSF1 that both sustain peritoneal macrophage growth.

16Mai/19

Sans A, Bonnafous S, Rousseau D, Patouraux S, Canivet CM, Leclere PS, Tran-Van-Nhieu J, Luci C, Bailly-Maitre B, Xu X, Lee AH, Minehira K, Anty R, Tran A, Iannelli A, Gual P

Sci Rep 2019 May;9(1):7501

Abstract

PMID: 31097771

Improved understanding of the molecular mechanisms responsible for the progression from a « non-pathogenic » steatotic state to Non-Alcoholic Steatohepatitis is an important clinical requirement. The cell death-inducing DFF45 like effector (CIDE) family members (A, B and FSP27) regulate hepatic lipid homeostasis by controlling lipid droplet growth and/or VLDL production. However, CIDE proteins, particularly FSP27, have a dual role in that they also regulate cell death. We here report that the hepatic expression of CIDEA and FSP27 (α/β) was similarly upregulated in a dietary mouse model of obesity-mediated hepatic steatosis. In contrast, CIDEA expression decreased, but FSP27-β expression strongly increased in a dietary mouse model of steatohepatitis. The inverse expression pattern of CIDEA and FSP27β was amplified with the increasing severity of the liver inflammation and injury. In obese patients, the hepatic CIDEC2 (human homologue of mouse FSP27β) expression strongly correlated with the NAFLD activity score and liver injury. The hepatic expression of CIDEA tended to increase with obesity, but decreased with NAFLD severity. In hepatic cell lines, the downregulation of FSP27β resulted in the fractionation of lipid droplets, whereas its overexpression decreased the expression of the anti-apoptotic BCL2 marker. This, in turn, sensitized cells to apoptosis in response to TNF α and saturated fatty acid. Considered together, our animal, human and in vitro studies indicate that differential expression of FSP27β/CIDEC2 and CIDEA is related to NAFLD progression and liver injury.

16Mai/19

Tulic MK, Cavazza E, Cheli Y, Jacquel A, Luci C, Cardot-Leccia N, Hadhiri-Bzioueche H, Abbe P, Gesson M, Sormani L, Regazzetti C, Beranger GE, Lereverend C, Pons C, Khemis A, Ballotti R, Bertolotto C, Rocchi S, Passeron T

Nat Commun 2019 05;10(1):2178

Abstract

PMID: 31097717

T-cells play a crucial role in progression of autoimmunity, including vitiligo, yet the initial steps triggering their activation and tissue damage remain unknown. Here we demonstrate increased presence of type-1 innate lymphoid cells (NK and ILC1)-producing interferon gamma (IFNγ) in the blood and in non-lesional skin of vitiligo patients. Melanocytes of vitiligo patients have strong basal expression of chemokine-receptor-3 (CXCR3) isoform B which is directly regulated by IFNγ. CXCR3B activation by CXCL10 at the surface of cultured human melanocytes induces their apoptosis. The remaining melanocytes, activated by the IFNγ production, express co-stimulatory markers which trigger T-cell proliferation and subsequent anti-melanocytic immunity. Inhibiting the CXCR3B activation prevents this apoptosis and the further activation of T cells. Our results emphasize the key role of CXCR3B in apoptosis of melanocytes and identify CXCR3B as a potential target to prevent and to treat vitiligo by acting at the early stages of melanocyte destruction.

01Mai/19

Corporeau C, Huvet A, Pichereau V, Delisle L, Quéré C, Dubreuil C, Artigaud S, Brenner C, Meyenberg Cunha-De Padua M, Mazure N

Med Sci (Paris) 2019 May;35(5):463-466

Abstract

PMID: 31115329

The Warburg effect is one of the hallmarks of cancer cells in humans. It is a true metabolic reprogramming to aerobic glycolysis, allowing cancer cells to meet their particular energy needs for growth, proliferation, and resistance to apoptosis, depending on the microenvironment they encounter within the tumor. We have recently discovered that the Crassostrea gigas oyster can naturally reprogram its metabolism to the Warburg effect. Thus, the oyster becomes a new invertebrate model useful for cancer research. Due to its lifestyle, the oyster C. gigas has special abilities to adapt its metabolism to the extreme changes in the environment in which it is located. The oyster C. gigas is therefore a model of interest to study how the environment can control the Warburg effect under conditions that could not be explored in vertebrate model species.

16Mar/19

Fabbri L, Bost F, Mazure NM

Int J Mol Sci 2019 Mar;20(6)

Abstract

PMID: 30884815

The primary cilium is a solitary, nonmotile and transitory appendage that is present in virtually all mammalian cells. Our knowledge of its ultrastructure and function is the result of more than fifty years of research that has dramatically changed our perspectives on the primary cilium. The mutual regulation between ciliogenesis and the cell cycle is now well-recognized, as well as the function of the primary cilium as a cellular « antenna » for perceiving external stimuli, such as light, odorants, and fluids. By displaying receptors and signaling molecules, the primary cilium is also a key coordinator of signaling pathways that converts extracellular cues into cellular responses. Given its critical tasks, any defects in primary cilium formation or function lead to a wide spectrum of diseases collectively called « ciliopathies ». An emerging role of primary cilium is in the regulation of cancer development. In this review, we seek to describe the current knowledge about the influence of the primary cilium in cancer progression, with a focus on some of the events that cancers need to face to sustain survival and growth in hypoxic microenvironment: the cancer hallmarks.

14Mar/19

Genin EC, Madji Hounoum B, Bannwarth S, Fragaki K, Lacas-Gervais S, Mauri-Crouzet A, Lespinasse F, Neveu J, Ropert B, Augé G, Cochaud C, Lefebvre-Omar C, Bigou S, Chiot A, Mochel F, Boillée S, Lobsiger CS, Bohl D, Ricci JE, Paquis-Flucklinger V

Acta Neuropathol. 2019 Mar;

Abstract

PMID: 30874923

Recently, we provided genetic basis showing that mitochondrial dysfunction can trigger motor neuron degeneration, through identification of CHCHD10 encoding a mitochondrial protein. We reported patients, carrying the p.Ser59Leu heterozygous mutation in CHCHD10, from a large family with a mitochondrial myopathy associated with motor neuron disease (MND). Rapidly, our group and others reported CHCHD10 mutations in amyotrophic lateral sclerosis (ALS), frontotemporal dementia-ALS and other neurodegenerative diseases. Here, we generated knock-in (KI) mice, carrying the p.Ser59Leu mutation, that mimic the mitochondrial myopathy with mtDNA instability displayed by the patients from our original family. Before 14 months of age, all KI mice developed a fatal mitochondrial cardiomyopathy associated with enhanced mitophagy. CHCHD10 mice also displayed neuromuscular junction (NMJ) and motor neuron degeneration with hyper-fragmentation of the motor end plate and moderate but significant motor neuron loss in lumbar spinal cord at the end stage of the disease. At this stage, we observed TDP-43 cytoplasmic aggregates in spinal neurons. We also showed that motor neurons differentiated from human iPSC carrying the p.Ser59Leu mutation were much more sensitive to Staurosporine or glutamate-induced caspase activation than control cells. These data confirm that mitochondrial deficiency associated with CHCHD10 mutations can be at the origin of MND. CHCHD10 is highly expressed in the NMJ post-synaptic part. Importantly, the fragmentation of the motor end plate was associated with abnormal CHCHD10 expression that was also observed closed to NMJs which were morphologically normal. Furthermore, we found OXPHOS deficiency in muscle of CHCHD10 mice at 3 months of age in the absence of neuron loss in spinal cord. Our data show that the pathological effects of the p.Ser59Leu mutation target muscle prior to NMJ and motor neurons. They likely lead to OXPHOS deficiency, loss of cristae junctions and destabilization of internal membrane structure within mitochondria at motor end plate of NMJ, impairing neurotransmission. These data are in favor with a key role for muscle in MND associated with CHCHD10 mutations.

02Mar/19

Guilbaud E, Gautier EL, Yvan-Charvet L

Cancers (Basel) 2019 Mar;11(3)

Abstract

PMID: 30832375

Macrophages are tissue-resident cells that act as immune sentinels to maintain tissue integrity, preserve self-tolerance and protect against invading pathogens. Lung macrophages within the distal airways face around 8000⁻9000 L of air every day and for that reason are continuously exposed to a variety of inhaled particles, allergens or airborne microbes. Chronic exposure to irritant particles can prime macrophages to mediate a smoldering inflammatory response creating a mutagenic environment and favoring cancer initiation. Tumor-associated macrophages (TAMs) represent the majority of the tumor stroma and maintain intricate interactions with malignant cells within the tumor microenvironment (TME) largely influencing the outcome of cancer growth and metastasis. A number of macrophage-centered approaches have been investigated as potential cancer therapy and include strategies to limit their infiltration or exploit their antitumor effector functions. Recently, strategies aimed at targeting IL-1 signaling pathway using a blocking antibody have unexpectedly shown great promise on incident lung cancer. Here, we review the current understanding of the bridge between TAM metabolism, IL-1 signaling, and effector functions in lung adenocarcinoma and address the challenges to successfully incorporating these pathways into current anticancer regimens.

26Fév/19

Robert G, Auberger P

Autophagy 2019 Feb;:1-3

Abstract

PMID: 30806567

Chaperone-mediated autophagy (CMA) is a selective form of autophagy that allows the elimination and recycling of cytosolic proteins endowed with a KFERQ-like motif into the lysosome. During this process, the proteins to be degraded are recognized by cellular chaperones such as HSC70 and presented to the CMA receptor LAMP2A, which then translocate them into lysosomes for degradation. In this punctum, we discuss the mechanisms underlying the response and resistance to Azacitidine (Aza) in MDS/AML cell lines and bone marrow CD34+ blasts from MDS/AML patients. We show that treatment of MDS/AML cell lines and bone marrow samples from MDS/AML patients with Aza triggers loss of LAMP2 expression leading to CMA defects. LAMP2 deficiency is responsible for CMA defects, Aza resistance and hypersensitivity to lysosome and autophagy inhibitors. Low levels of LAMP2 expression in CD34+ blasts from MDS/AML patients correlate with an absence of response to Aza and are associated to a pejorative overall survival. We propose that CD34+/LAMP2Low patients at diagnosis or who become CD34+/LAMP2Low during the course of treatment with Aza could receive an autophagy inhibitor available in the clinic.

25Fév/19

Torrino S, Roustan FR, Kaminski L, Bertero T, Pisano S, Ambrosetti D, Dufies M, Uhler JP, Lemichez E, Mettouchi A, Gesson M, Laurent K, Gaggioli C, Michiels JF, Lamaze C, Bost F, Clavel S

EMBO Rep. 2019 Feb;

Abstract

PMID: 30804013

Ubiquitin domain-containing protein 1 (UBTD1) is highly evolutionary conserved and has been described to interact with E2 enzymes of the ubiquitin-proteasome system. However, its biological role and the functional significance of this interaction remain largely unknown. Here, we demonstrate that depletion of UBTD1 drastically affects the mechanical properties of epithelial cancer cells via RhoA activation and strongly promotes their aggressiveness. On a stiff matrix, UBTD1 expression is regulated by cell-cell contacts, and the protein is associated with β-catenin at cell junctions. Yes-associated protein (YAP) is a major cell mechano-transducer, and we show that UBTD1 is associated with components of the YAP degradation complex. Interestingly, UBTD1 promotes the interaction of YAP with its E3 ubiquitin ligase β-TrCP Consequently, in cancer cells, UBTD1 depletion decreases YAP ubiquitylation and triggers robust ROCK2-dependent YAP activation and downstream signaling. Data from lung and prostate cancer patients further corroborate the results, confirming that low levels of UBTD1 are associated with poor patient survival, suggesting that biological functions of UBTD1 could be beneficial in limiting cancer progression.

21Fév/19

Hofman P, Ayache N, Barbry P, Barlaud M, Bel A, Blancou P, Checler F, Chevillard S, Cristofari G, Demory M, Esnault V, Falandry C, Gilson E, Guérin O, Glaichenhaus N, Guigay J, Ilié M, Mari B, Marquette CH, Paquis-Flucklinger V, Prate F, Saintigny P, Seitz-Polsky B, Skhiri T, Van Obberghen-Schilling E, Van Obberghen E, Yvan-Charvet L

Cancers (Basel) 2019 02;11(2)

Abstract

PMID: 30795607

It is generally accepted that carcinogenesis and aging are two biological processes, which are known to be associated. Notably, the frequency of certain cancers (including lung cancer), increases significantly with the age of patients and there is now a wealth of data showing that multiple mechanisms leading to malignant transformation and to aging are interconnected, defining the so-called common biology of aging and cancer. OncoAge, a consortium launched in 2015, brings together the multidisciplinary expertise of leading public hospital services and academic laboratories to foster the transfer of scientific knowledge rapidly acquired in the fields of cancer biology and aging into innovative medical practice and silver economy development. This is achieved through the development of shared technical platforms (for research on genome stability, (epi)genetics, biobanking, immunology, metabolism, and artificial intelligence), clinical research projects, clinical trials, and education. OncoAge focuses mainly on two pilot pathologies, which benefit from the expertise of several members, namely lung and head and neck cancers. This review outlines the broad strategic directions and key advances of OncoAge and summarizes some of the issues faced by this consortium, as well as the short- and long-term perspectives.

18Fév/19

Raffort J, Lareyre F, Clément M, Moratal C, Jean-Baptiste E, Hassen-Khodja R, Burel-Vandenbos F, Bruneval P, Chinetti G, Mallat Z

J. Vasc. Surg. 2019 Feb;

Abstract

PMID: 30792060

OBJECTIVE: Macrophages play a critical role in the initiation and progression of abdominal aortic aneurysm (AAA) and are classically distinguished into M1 « proinflammatory » and M2 « anti-inflammatory » macrophages. Topical application of elastase associated with transforming growth factor β (TGF-β) systemic neutralization reproduces the main pathologic features of human AAA, offering a new model to investigate their role. The aim of this study was to investigate whether macrophages contribute to the expression of canonical M1/M2 markers in the aorta in the AAA model induced by elastase and systemic blockade of TGF-β and whether blocking of TGF-β activity affects macrophage phenotype and the expression of the M2 marker arginase 1 (ARG1).

METHODS: C57Bl/6J male mice (6-8 weeks old) were randomly assigned to three experimental groups: mice that had local application of heat-inactivated elastase or elastase and mice that had elastase application and received injection of anti-TGF-β (elastase + anti-TGF-β group). Monocyte-macrophage depletion was achieved in the elastase + anti-TGF-β group using liposome clodronate. Macrophage phenotype was characterized by quantitative polymerase chain reaction, flow cytometry, and immunohistochemistry. Human infrarenal AAA tissues (n = 10) were obtained to analyze ARG1 expression.

RESULTS: Analysis of gene expression in the infrarenal aortic wall revealed that after 14 days, no significant difference for the expression of CCL2, NOS2, and Ym1/2 was observed in the elastase group compared with the elastase + anti-TGF-β group, whereas the expression of ARG1, interleukin (IL) 1β, and IL-6 was significantly increased. Macrophage depletion in the elastase + anti-TGF-β group led to a significant decrease of IL-1β, IL-6, ARG1, and Ym1/2 gene expression. Immunofluorescent staining confirmed that TGF-β neutralization significantly enhanced ARG1 protein expression in the aneurysmal tissue. Flow cytometry analysis revealed an increase of macrophages expressing ARG1 in the aorta of mice treated with elastase + anti-TGF-β compared with the elastase group, and their proportion increased with aneurysmal dilation. In humans, ARG1 protein expression was increased in aneurysmal tissues compared with controls, and positive cells were mainly found in the adventitia.

CONCLUSIONS: TGF-β neutralization finely tunes macrophage phenotype in elastase-induced AAA and leads to an increase in ARG1 gene and protein expression in the aortic wall. Even if further studies are required to elucidate its role in AAA development, ARG1 could represent a new prognostic or therapeutic target in aneurysmal disease.

05Fév/19

Varin EM, Mulvihill EE, Beaudry JL, Pujadas G, Fuchs S, Tanti JF, Fazio S, Kaur K, Cao X, Baggio LL, Matthews D, Campbell JE, Drucker DJ

Cell Metab. 2019 Feb;29(2):320-334.e5

Abstract

PMID: 30393019

Dipeptidyl peptidase-4 (DPP-4) controls glucose homeostasis through enzymatic termination of incretin action. We report that plasma DPP-4 activity correlates with body weight and fat mass, but not glucose control, in mice. Genetic disruption of adipocyte Dpp4 expression reduced plasma DPP-4 activity in older mice but did not perturb incretin levels or glucose homeostasis. Knockdown of hepatocyte Dpp4 completely abrogated the obesity-associated increase in plasma DPP-4 activity, reduced liver cytokine expression, and partially attenuated inflammation in adipose tissue without changes in incretin levels or glucose homeostasis. In contrast, circulating levels of soluble DPP4 (sDPP4) were dissociated from inflammation in mice with endothelial-selective or global genetic inactivation of Dpp4. Remarkably, inhibition of DPP-4 enzymatic activity upregulated circulating levels of sDPP4 originating from endothelial or hematopoietic cells without inducing systemic or localized inflammation. Collectively, these findings reveal unexpected complexity in regulation of soluble versus enzymatic DPP-4 and control of inflammation and glucose homeostasis.

05Fév/19

Zhang S, Weinberg S, DeBerge M, Gainullina A, Schipma M, Kinchen JM, Ben-Sahra I, Gius DR, Yvan-Charvet L, Chandel NS, Schumacker PT, Thorp EB

Cell Metab. 2019 Feb;29(2):443-456.e5

Abstract

PMID: 30595481

During wound injury, efferocytosis fills the macrophage with a metabolite load nearly equal to the phagocyte itself. A timely question pertains to how metabolic phagocytic signaling regulates the signature anti-inflammatory macrophage response. Here we report the metabolome of activated macrophages during efferocytosis to reveal an interleukin-10 (IL-10) cytokine escalation that was independent of glycolysis yet bolstered by apoptotic cell fatty acids and mitochondrial β-oxidation, the electron transport chain, and heightened coenzyme NAD. Loss of IL-10 due to mitochondrial complex III defects was remarkably rescued by adding NAD precursors. This activated a SIRTUIN1 signaling cascade, largely independent of ATP, that culminated in activation of IL-10 transcription factor PBX1. Il-10 activation by the respiratory chain was also important in vivo, as efferocyte mitochondrial dysfunction led to cardiac rupture after myocardial injury. These findings highlight a new paradigm whereby macrophages leverage efferocytic metabolites and electron transport for anti-inflammatory reprogramming that culminates in organ repair.

01Fév/19

Leclerc J, Garandeau D, Pandiani C, Gaudel C, Bille K, Nottet N, Garcia V, Colosetti P, Pagnotta S, Bahadoran P, Tondeur G, Mograbi B, Dalle S, Caramel J, Levade T, Ballotti R, Andrieu-Abadie N, Bertolotto C

Oncogene 2019 02;38(8):1282-1295

Abstract

PMID: 30254208

Phenotypic plasticity and subsequent generation of intratumoral heterogeneity underly key traits in malignant melanoma such as drug resistance and metastasis. Melanoma plasticity promotes a switch between proliferative and invasive phenotypes characterized by different transcriptional programs of which MITF is a critical regulator. Here, we show that the acid ceramidase ASAH1, which controls sphingolipid metabolism, acted as a rheostat of the phenotypic switch in melanoma cells. Low ASAH1 expression was associated with an invasive behavior mediated by activation of the integrin alphavbeta5-FAK signaling cascade. In line with that, human melanoma biopsies revealed heterogeneous staining of ASAH1 and low ASAH1 expression at the melanoma invasive front. We also identified ASAH1 as a new target of MITF, thereby involving MITF in the regulation of sphingolipid metabolism. Together, our findings provide new cues to the mechanisms underlying the phenotypic plasticity of melanoma cells and identify new anti-metastatic targets.

01Fév/19

Wiedemann GM, Aithal C, Kraechan A, Heise C, Cadilha BL, Zhang J, Duewell P, Ballotti R, Endres S, Bertolotto C, Kobold S

Transl Oncol 2019 Feb;12(2):350-360

Abstract

PMID: 30502589

Microphthalmia-associated transcription factor (MITF) is a key transcription factor in melanoma development and progression. MITF amplification and downregulation have been observed in a significant proportion of melanoma patients and correlate with clinical outcomes. Here, we have investigated the effect of MITF on melanoma chemokine expression and immune cell attraction. In B16F10 melanoma cells, MITF knockdown reduced expression of CXCL10, with concomitantly decreased attraction of immune cells and accelerated tumor outgrowth. Conversely, overexpression of MITF in YUMM1.1 melanoma cells also led to an increased immune cell attraction in vitro. Subcutaneous YUMM1.1 melanomas overexpressing MITF however showed a reduced immune infiltration of lymphocytes and an increased tumor growth. In human melanoma cell lines, silencing of MITF enhanced chemokine production and immune cell attraction, while overexpression of MITF led to lower immune cell attraction. In summary, our results show that MITF regulates chemokine expression in murine and in human melanoma cells, and affects in vivo immune cell attraction and tumor growth. These results reveal a functional relationship between MITF and immune cell infiltration, which may be exploited for cancer therapy.

22Jan/19

Portha B, Grandjean V, Movassat J

Nutrients 2019 Jan;11(2)

Abstract

PMID: 30678214

Extensive epidemiological and experimental evidence have shown that exposure to an adverse intrauterine environment as observed in offspring of pregnancies complicated by obesity or diabetes, can program susceptibility to metabolic, endocrine and cardiovascular disorders later in life. Although most studies have concentrated on the maternal environment, it is also becoming evident that paternal exposure to obesity or diabetes can result in the later development of metabolic disorders in the offspring. Such programmed effects might not be limited to the first directly exposed generation, but could be transmitted to subsequent generations. This suggests the existence of mechanisms by which metabolic changes in parental phenotype are transmissible to offspring. The mechanisms which underpin the transmission of the programmed effects across generations are still unclear. However, epigenetic regulation of transcription has emerged as a strong candidate for mediating the heritability of metabolic diseases. Here, we review the most relevant evidence from human and animal studies showing transmission of programming effects of obesity or diabetes across generations, and the current mechanisms underlying either maternal or paternal influences on the metabolic status of offspring.

03Jan/19

Dubois A, Furstoss N, Calleja A, Zerhouni M, Cluzeau T, Savy C, Marchetti S, Hamouda MA, Boulakirba S, Orange F, Lacas-Gervais S, Karsenti JM, Mounier N, Tamburini J, Puissant A, Luciano F, Jacquel A, Auberger P, Robert G

Leukemia 2019 Jan;

Abstract

PMID: 30607021

Chaperone-mediated autophagy (CMA) is a highly selective form of autophagy. During CMA, the HSC70 chaperone carries target proteins endowed with a KFERQ-like motif to the lysosomal receptor LAMP2A, which then translocate them into lysosomes for degradation. In the present study, we scrutinized the mechanisms underlying the response and resistance to Azacytidine (Aza) in MDS/AML cell lines and bone marrow CD34 blasts from MDS/AML patients. In engineered Aza-resistant MDS cell lines and some AML cell lines, we identified a profound defect in CMA linked to the absence of LAMP2A. LAMP2 deficiency was responsible for Aza resistance and hypersensitivity to lysosome and autophagy inhibitors. Accordingly, gain of function of LAMP2 in deficient cells or loss of function in LAMP2-expressing cells rendered them sensitive or resistant to Aza, respectively. A strict correlation was observed between the absence of LAMP2, resistance to Aza and sensitivity to lysosome inhibitors. Low levels of LAMP2 expression in CD34 blasts from MDS/AML patients correlated with lack of sensitivity to Aza and were predictive of poor overall survival. We propose that CD34/LAMP2 patients at diagnosis or who become CD34/LAMP2 during the course of treatment with Aza might benefit from a lysosome inhibitor already used in the clinic.

01Jan/19

Trabucchi M

Trends Genet. 2019 Jan;35(1):15-28

Abstract

PMID: 30503571

Different methods have recently been developed to understand the subcellular localization and role of microRNAs (miRNAs) as well as small RNAs associated with Argonaute (AGO) proteins. The heterogeneity of the protein complexes associated with miRNAs, along with their subcellular localization, provides clues into their biochemical mechanism of function. Subcellular diversity indicates that miRNAs localized to different cellular regions could have different functions, including transcriptional regulation on chromatin or post-transcriptional control, providing global regulation of gene expression by miRNAs. Herein, I review the current knowledge and most recent discoveries relating to the subcellular function of miRNAs and other AGO-associated small RNAs, revealing the emergence of a multitude of functions of the miRNA pathway to control different steps of the gene expression program(s).

01Jan/19

Raad G, Azouri J, Rizk K, Zeidan NS, Azouri J, Grandjean V, Hazzouri M

PLoS ONE 2019;14(2):e0211837

Abstract

PMID: 30742661

Growing evidence suggests that paternal obesity may decrease male fertility potential. During infertility treatment with intra-cytoplasmic sperm injection (ICSI), a morphologically normal motile spermatozoon is injected into a mature egg, when possible. However, sperm motility and morphology per se do not reflect the sperm molecular composition. In this study, we aimed to assess the quality of motile spermatozoa in the context of obesity by analysing their conventional and molecular characteristics as well as their ability to promote early embryonic development. A prospective study was conducted on 128 infertile men divided into three groups: 40 lean, 42 overweight, and 46 obese men. Conventional sperm parameters (concentration, motility and morphology) and sperm molecular status (chromatin composition and integrity, 5-methycytosine (5-mC) and 5-hydroxycytosine (5-hmC) contents and oxidative stress level) were analysed on raw semen and/or on motile spermatozoa selected by density gradient or swim-up techniques. Morphokinetic analysis of the embryos derived from ICSI was performed using the Embryoviewer software. Our results showed that the motile sperm-enriched fraction from obese men exhibited higher levels of retained histones (p<0.001), elevated percentage of altered chromatin integrity (p<0.001), and decreased contents of 5-hmC (p<0.001), and 5-mC (p<0.05) levels as compared to that from lean men. Importantly, there were no statistically significant correlations between these molecular parameters and the percentages of morphologically normal motile spermatozoa. Regarding embryo morphokinetics, the CC1 (p<0.05) and CC3 (p<0.05) embryonic cell cycles were significantly delayed in the cleavage embryos of the obese group as compared to the embryos of the lean group. Our data is of particular interest because, besides demonstrating the negative impacts of obesity on motile spermatozoa molecular composition, it also highlights the possible risk of disturbing early embryonic cell cycles kinetics in the context of paternal obesity.

01Jan/19

Siddeek B, Mauduit C, Chehade H, Blin G, Liand M, Chindamo M, Benahmed M, Simeoni U

Cell Death Discov 2019;5:71

Abstract

PMID: 30854230

Heart failure is a worldwide leading cause of death. Diet and obesity are particularly of high concern in heart disease etiology. Gravely, altered nutrition during developmental windows of vulnerability can have long-term impact on heart health; however, the underlying mechanisms are poorly understood. In the understanding of the initiation of chronic diseases related to developmental exposure to environmental challenges, deregulations in epigenetic mechanisms including micro-RNAs have been proposed as key events. In this context, we aimed at delineating the role of micro-RNAs in the programming of cardiac alterations induced by early developmental exposure to nutritional imbalance. To reach our aim, we developed a human relevant model of developmental exposure to nutritional imbalance by maternally exposing rat to high-fat diet during gestation and lactation. In this model, offspring exposed to maternal high-fat diet developed cardiac hypertrophy and increased extracellular matrix depot compared to those exposed to chow diet. Microarray approach performed on cardiac tissue allowed the identification of a micro-RNA subset which was down-regulated in high-fat diet-exposed animals and which were predicted to regulate transforming growth factor-beta (TGFβ)-mediated remodeling. As indicated by in vitro approaches and gene expression measurement in the heart of our animals, decrease in DiGeorge critical region 8 (DGCR8) expression, involved in micro-RNA biogenesis, seems to be a critical point in the alterations of the micro-RNA profile and the TGFβ-mediated remodeling induced by maternal exposure to high-fat diet. Finally, increasing DGCR8 activity and/or expression through hemin treatment in vitro revealed its potential in the rescue of the pro-fibrotic phenotype in cardiomyocytes driven by DGCR8 decrease. These findings suggest that cardiac alterations induced by maternal exposure to high-fat diet is related to abnormalities in TGFβ pathway and associated with down-regulated micro-RNA processing. Our study highlighted DGCR8 as a potential therapeutic target for heart diseases related to early exposure to dietary challenge.

01Jan/19

Zhang S, Bories G, Lantz C, Emmons R, Becker A, Liu E, Abecassis MM, Yvan-Charvet L, Thorp EB

Front Cardiovasc Med 2019;6:42

Abstract

PMID: 31032261

Cardiovascular disease remains the leading cause of death worldwide. Myocardial ischemia is a major contributor to cardiovascular morbidity and mortality. In the case of acute myocardial infarction, subsequent cardiac repair relies upon the acute, and coordinated response to injury by innate myeloid phagocytes. This includes neutrophils, monocytes, macrophage subsets, and immature dendritic cells. Phagocytes function to remove necrotic cardiomyocytes, apoptotic inflammatory cells, and to remodel extracellular matrix. These innate immune cells also secrete cytokines and growth factors that promote tissue replacement through fibrosis and angiogenesis. Within the injured myocardium, macrophages polarize from pro-inflammatory to inflammation-resolving phenotypes. At the core of this functional plasticity is cellular metabolism, which has gained an appreciation for its integration with phagocyte function and remodeling of the transcriptional and epigenetic landscape. Immunometabolic rewiring is particularly relevant after ischemia and clinical reperfusion given the rapidly changing oxygen and metabolic milieu. Hypoxia reduces mitochondrial oxidative phosphorylation and leads to increased reliance on glycolysis, which can support biosynthesis of pro-inflammatory cytokines. Reoxygenation is permissive for shifts back to mitochondrial metabolism and fatty acid oxidation and this is ultimately linked to pro-reparative macrophage polarization. Improved understanding of mechanisms that regulate metabolic adaptations holds the potential to identify new metabolite targets and strategies to reduce cardiac damage through nutrient signaling.

01Jan/19

Meyenberg Cunha-de Padua M, Noleto GR, de Oliveira Petkowicz CL, Cadena SMSC, Bost F, Pouysségur J, Mazure NM

Cell. Mol. Biol. Lett. 2019;24:18

Abstract

PMID: 30949212

Background: Polysaccharides from various sources have been used in traditional medicine for centuries. The beneficial pharmacological effects of plant-derived polysaccharides include anti-tumor activity.

Methods: Here, we evaluated the anti-cancer effect of the MSAGM:VO complex under hypoxic conditions (1% oxygen). MSAGM:VO is a complex of the hydrolysate of galactomannan (MSAGM) from with oxovanadium (IV/V). The hepatocellular carcinoma (HCC) cell line HepG2 was selected as HCC are one of the most hypoxic solid tumors.

Results: Our results showed that the strong apoptotic activity of MSAGM:VO observed in HepG2 cells under normoxic conditions was completely lost under hypoxic conditions. We found a dynamic balance between the pro- and anti-apoptotic members of the Bcl-2 protein family. The expressions of anti-apoptotic Mcl-1 and Bcl-X increased in hypoxia, whereas the expression of pro-apoptotic Bax decreased. MSAGM:VO strongly induced autophagy, which was previously characterized as a pro-survival mechanism in hypoxia. These results demonstrate total elimination of the anti-cancer activity of MSAGM:VO with activation of autophagy under conditions of hypoxia.

Conclusion: Although this study is a proof-of-concept of the impact of hypoxia on the potential of polysaccharides, further study is encouraged. The anti-tumor activity of polysaccharides could be achieved in normoxia or through raising the activity of the immune system. In addition, combination strategies for therapy with anti-autophagic drugs could be proposed.

01Jan/19

Bost F, Kaminski L

Am J Cancer Res 2019;9(2):198-211

Abstract

PMID: 30906622

The peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a central modulator of cell metabolism. It regulates mitochondrial biogenesis and oxidative metabolism. Modifications and adaptations in cellular metabolism are hallmarks of cancer cells, thus, it is not surprising that PGC-1α plays a role in cancer. Several recent articles have shown that PGC-1α expression is altered in tumors and metastasis in relation to modifications in cellular metabolism. The potential uses of PGC-1α as a therapeutic target and a biomarker of the advanced form of cancer will be summarized in this review.

01Jan/19

Lareyre F, Reverso-Meinietti J, Carboni J, Gaudart A, Hassen-Khodja R, Raffort J

Vasc Endovascular Surg 2019 Jan;53(1):86-91

Abstract

PMID: 30213242

Although intravesical therapy with bacillus Calmette-Guérin (BCG) has proven its efficiency in the treatment of early-stage bladder cancer, infectious complications can occur and mycotic aneurysms represent a rare but life-threatening complication. Here, we report the case of an aortic graft infection in a patient with abdominal aortic aneurysm who received BCG instillations for the treatment of bladder cancer. Based on the current knowledge on this rare vascular complication, we discuss factors that may have contributed to its occurrence and review issues to optimize its management and early detection.

01Jan/19

Dupont C, Kappeler L, Saget S, Grandjean V, Lévy R

Front Genet 2019;10:337

Abstract

PMID: 31057600

The concept of Developmental Origins of Health and Diseases (DOHaD) recognizes that an unfavorable maternal environment alters the developmental trajectory of the fetus and can lead to long-term risk of developing chronic noncommunicable diseases. More recently, the concept of a paternal transmission [Paternal Origins of Health and Diseases (POHaD)] has emerged stressing the impact of paternal overweight or obesity on offspring’s health and development. While very few examples of paternal epigenetic inheritance of metabolic disorders have been evidenced in human, many experimental mouse models based on high-fat diet (HFD)-induced paternal obesity have been developed to breakdown molecular mechanisms involved in the process. Besides DNA methylation and chromatin structure, sperm short noncoding RNAs have been considered as the main epigenetic vector of inheritance of paternally environmentally induced changes. Among them, sperm miRNAs are one particular subspecies sensitive to environmental changes and obesity can modify the sperm miRNA profile. Once delivered into the zygote, these molecules might induce epigenetic modifications in the embryo, thereby leading to consequences for fetus development and offspring physical and metabolic health later on in life. Furthermore, some data also suggest that metabolic pathologies may be intergenerationally or transgenerationally transmitted.

01Jan/19

Lareyre F, Carboni J, Chikande J, Massiot N, Voury-Pons A, Umbdenstock E, Jean-Baptiste E, Hassen-Khodja R, Raffort J

Vasc Endovascular Surg 2019 Jan;53(1):5-11

Abstract

PMID: 30021492

INTRODUCTION:: The predictive value of the platelet to lymphocyte ratio (PLR) has been demonstrated in several cardiovascular diseases. The aim of this study was to investigate the interest of the preoperative PLR as a predictor of 30-day postoperative outcome in patients with abdominal aortic aneurysm (AAA) undergoing open or endovascular surgical repair.

MATERIAL AND METHODS:: Two hundred twenty-four consecutive patients with infrarenal AAA were retrospectively included and divided into 4 quartiles according to the value of the preoperative PLR: PLR < 91.5 (group I), 91.5 < PLR < 120.8 (group II), 120.8 < PLR < 163.3 (group III), and PLR > 163.3 (group IV).

RESULTS:: The AAA diameter was similar among the groups (54.9 mm vs 58.6, 57.5, and 58.7 mm; P = .4655). The proportion of symptomatic AAA and the procedural characteristics did not differ. Patients from group I and IV had significantly higher rates of all-cause postoperative complications compared to group II and III (55.4% and 64.3% vs 39.3% and 46.4%, respectively; P = .0478). The all-cause mortality tended to be higher in group I and IV (7.1% and 8.9% vs 0% and 3.6%, respectively; P = .1305).

CONCLUSION:: Extreme values of PLR are associated with a higher risk of complications following AAA surgical repair, suggesting its interest as a biomarker to evaluate the surgical risk.

01Jan/19

Massiot N, Lareyre F, Voury-Pons A, Pelletier Y, Chikande J, Carboni J, Umbdenstock E, Jean-Baptiste E, Hassen-Khodja R, Raffort J

J Stroke Cerebrovasc Dis 2019 Jan;28(1):76-83

Abstract

PMID: 30268367

INTRODUCTION: The neutrophil to lymphocyte ratio (NLR) and the platelet to lymphocyte ratio (PLR) have been identified as predictive factors in several cardiovascular diseases but their significance in patients with internal carotid artery (ICA) stenosis is still poorly known. The aim of this study was to determine the clinical significance of the preoperative NLR and PLR in patients with ICA stenosis undergoing carotid endarterectomy.

MATERIAL AND METHODS: Consecutive patients who underwent carotid endarterectomy for ICA stenosis were retrospectively included (n = 270). The population was divided into 2 series of 4 groups based on the quartile values of the preoperative NLR and PLR: group Ia (NLR < 1.5), IIa (1.50 < NLR < 2.07), IIIa (2.07 < NLR < 2.95), IVa (NLR>2.95), and group Ib (PLR < 86.6), IIb (86.6 < PLR < 111.7), IIIb (111.7 < PLR < 148.3), IVb (PLR > 148.3). Clinical characteristics and 30-day postoperative outcomes were compared among the groups.

RESULTS: One death (.4%) was reported during the 30-day postoperative period and the overall stroke and death rate was 1.5%. The proportion of patients with symptomatic ICA stenosis were significantly higher in group IVa compared to groups Ia, IIa, IIIa (64.2% vs 33.8%, 44.8% and 45.6%, respectively, P = .005), and higher in group IVb compared to groups Ib, IIb, IIIb (59.7% vs 47.1%, 35.8%, 45.6%, P = .051). No significant difference on 30-day postoperative all-cause complications was observed among the groups.

CONCLUSIONS: A high preoperative NLR and PLR is significantly associated with symptomatic ICA stenosis. Further studies are required to determine their interest as predictors of postoperative outcomes in patients undergoing carotid endarterectomy.

18Déc/18

Gilleron J, Bouget G, Ivanov S, Meziat C, Ceppo F, Vergoni B, Djedaini M, Soprani A, Dumas K, Jacquel A, Yvan-Charvet L, Venteclef N, Tanti JF, Cormont M

Cell Rep 2018 Dec;25(12):3329-3341.e5

Abstract

PMID: 30566860

Obesity modifies T cell populations in adipose tissue, thereby contributing to adipose tissue inflammation and insulin resistance. Here, we show that Rab4b, a small GTPase governing endocytic trafficking, is pivotal in T cells for the development of these pathological events. Rab4b expression is decreased in adipose T cells from mice and patients with obesity. The specific depletion of Rab4b in T cells causes adipocyte hypertrophy and insulin resistance in chow-fed mice and worsens insulin resistance in obese mice. This phenotype is driven by an increase in adipose Th17 and a decrease in adipose Treg due to a cell-autonomous skew of differentiation toward Th17. The Th17/Treg imbalance initiates adipose tissue inflammation and reduces adipogenesis, leading to lipid deposition in liver and muscles. Therefore, we propose that the obesity-induced loss of Rab4b in adipose T cells may contribute to maladaptive white adipose tissue remodeling and insulin resistance by altering adipose T cell fate.

01Nov/18

Raffort J, Lareyre F, Clément M, Hassen-Khodja R, Chinetti G, Mallat Z

Cardiovasc. Res. 2018 Nov;114(13):1702-1713

Abstract

PMID: 30052821

Aortic aneurysm is a life-threatening disease due to the risk of aortic rupture. The only curative treatment available relies on surgical approaches; drug-based therapies are lacking, highlighting an unmet need for clinical practice. Abdominal aortic aneurysm (AAA) is frequently associated with atherosclerosis and cardiovascular risk factors including male sex, age, smoking, hypertension, and dyslipidaemia. Thoracic aortic aneurysm (TAA) is more often linked to genetic disorders of the extracellular matrix and the contractile apparatus but also share similar cardiovascular risk factors. Intriguingly, a large body of evidence points to an inverse association between diabetes and both AAA and TAA. A better understanding of the mechanisms underlying the negative association between diabetes and aortic aneurysm could help the development of innovative diagnostic and therapeutic approaches to tackle the disease. Here, we summarize current knowledge on the relationship between glycaemic parameters, diabetes, and the development of aortic aneurysm. Cellular and molecular pathways that underlie the protective effect of diabetes itself and its treatment are reviewed and discussed, along with their potential implications for clinical translation.

01Nov/18

Villa E, Marchetti S, Ricci JE

Trends Cell Biol. 2018 Nov;28(11):882-895

Abstract

PMID: 30115557

Mitochondria are essential highly dynamic organelles that provide the necessary energy for a variety of different processes, such as survival, proliferation, and migration. In order to maintain an intact mitochondrial network, cells have developed quality control systems that allow the removal of damaged or superfluous mitochondria by selective mitochondrial autophagy called mitophagy. Although the parkin/PINK1 axis is often considered the main regulator of mitophagy, a growing body of evidence has shown that this pathway is not unique and that mitophagy can still be functional in the absence of parkin. Here, we will review recent literature describing parkin-independent mitophagy and its role in various physiopathological conditions, therefore representing potential new targets to treat diseases affected by dysregulated mitophagy.

01Nov/18

Taquin H, Fontas E, Massol O, Chevallier P, Balloti R, Beranger G, Lacour JP, Passeron T, Montaudié H

Ann Dermatol Venereol 2018 Nov;145(11):649-658

Abstract

PMID: 30098818

BACKGROUND: Immunotherapies using anti-CTLA4 and anti-PD1 antibodies have revolutionised the management of patients with advanced melanoma. The aim of our study was to analyse the efficacy and safety of immunotherapies in patients with advanced melanoma under real-life conditions.

METHODS: We conducted a monocentric, retrospective, observational study that included all patients treated with immunotherapies (ipilimumab, i.e. ipi; nivolumab, i.e. niv and pembrolizumab, i.e. pbr) for advanced melanoma with exclusion of primary mucosal or ocular melanoma. The primary endpoint was progression-free survival (PFS).

RESULTS: A total of 110 patients were included. Median PFS was better in the anti-PD1 group than in the anti-CTLA4 group (3.9 months vs. 2.9 months, P=0.025). The frequency of adverse events of any grade was 53.4% with ipi, 66.7% with niv and 75% with pbr.

DISCUSSION: Our study shows slightly inferior efficacy data vs. clinical trials of ipi and niv because patients were presenting more severe illness at inclusion. Nevertheless, the study argues in favour of the superiority of anti-PD1 antibodies vs. anti-CTLA4 antibodies in terms of PFS and best overall response. Moreover, our study exhibits safety data comparable to those from clinical trials except for a lower frequency with ipi.

CONCLUSION: Our efficacy and safety data obtained under real-life conditions are reassuring since they are consistent with data already published.

01Nov/18

Genin EC, Bannwarth S, Lespinasse F, Ortega-Vila B, Fragaki K, Itoh K, Villa E, Lacas-Gervais S, Jokela M, Auranen M, Ylikallio E, Mauri-Crouzet A, Tyynismaa H, Vihola A, Augé G, Cochaud C, Sesaki H, Ricci JE, Udd B, Vives-Bauza C, Paquis-Flucklinger V

Neurobiol. Dis. 2018 Nov;119:159-171

Abstract

PMID: 30092269

Following the involvement of CHCHD10 in FrontoTemporal-Dementia-Amyotrophic Lateral Sclerosis (FTD-ALS) clinical spectrum, a founder mutation (p.Gly66Val) in the same gene was identified in Finnish families with late-onset spinal motor neuronopathy (SMAJ). SMAJ is a slowly progressive form of spinal muscular atrophy with a life expectancy within normal range. In order to understand why the p.Ser59Leu mutation, responsible for severe FTD-ALS, and the p.Gly66Val mutation could lead to different levels of severity, we compared their effects in patient cells. Unlike affected individuals bearing the p.Ser59Leu mutation, patients presenting with SMAJ phenotype have neither mitochondrial myopathy nor mtDNA instability. The expression of CHCHD10 mutant allele leads to disassembly of mitochondrial contact site and cristae organizing system (MICOS) with mitochondrial dysfunction and loss of cristae in patient fibroblasts. We also show that G66V fibroblasts do not display the loss of MICOS complex integrity and mitochondrial damage found in S59L cells. However, S59L and G66V fibroblasts show comparable accumulation of phosphorylated mitochondrial TDP-43 suggesting that the severity of phenotype and mitochondrial damage do not depend on mitochondrial TDP-43 localization. The expression of the CHCHD10 allele is responsible for mitochondrial network fragmentation and decreased sensitivity towards apoptotic stimuli, but with a less severe effect than that found in cells expressing the CHCHD10 allele. Taken together, our data show that cellular phenotypes associated with p.Ser59Leu and p.Gly66Val mutations in CHCHD10 are different; loss of MICOS complex integrity and mitochondrial dysfunction, but not TDP-43 mitochondrial localization, being likely essential to develop a severe motor neuron disease.

04Oct/18

Le Menn G, Sibille B, Murdaca J, Rousseau AS, Squillace R, Vergoni B, Cormont M, Niot I, Grimaldi PA, Mothe-Satney I, Neels JG

FASEB J. 2018 Oct;:fj201800696RR

Abstract

PMID: 30285581

The implication of αβ and γδ T cells in obesity-associated inflammation and insulin resistance (IR) remains uncertain. Mice lacking γδ T cells show either no difference or a decrease in high-fat diet (HFD)-induced IR, whereas partial depletion in γδ T cells does not protect from HFD-induced IR. αβ T-cell deficiency leads to a decrease in white adipose tissue (WAT) inflammation and IR without weight change, but partial depletion of these cells has not been studied. We previously described a mouse model overexpressing peroxisome proliferator-activated receptor β (PPAR-β) specifically in T cells [transgenic (Tg) T-PPAR-β] that exhibits a partial depletion in αβ T cells and no change in γδ T-cell number. This results in a decreased αβ/γδ T-cell ratio in lymphoid organs. We now show that Tg T-PPAR-β mice are partially protected against HFD-induced weight gain and exhibit decreased IR and liver steatosis independently of animal weight. These mice display an alteration of WAT-depots distribution with an increased epididymal-WAT mass and a decreased subcutaneous WAT mass. Immune cell number is decreased in both WAT-depots, except for γδ T cells, which are increased in epididymal-WAT. Overall, we show that decreasing αβ/γδ T-cell ratio in WAT-depots alters their inflammatory state and mass repartition, which might be involved in improvement of insulin sensitivity.-Le Menn, G., Sibille, B., Murdaca, J., Rousseau, A.-S., Squillace, R., Vergoni, B., Cormont, M., Niot, I., Grimaldi, P. A., Mothe-Satney, I., Neels, J. G. Decrease in αβ/γδ T-cell ratio is accompanied by a reduction in high-fat diet-induced weight gain, insulin resistance, and inflammation.

01Oct/18

Berthe A, Zaffino M, Muller C, Foulquier F, Houdou M, Schulz C, Bost F, De Fay E, Mazerbourg S, Flament S

Breast Cancer Res. Treat. 2018 Oct;171(3):581-591

Abstract

PMID: 29971627

PURPOSE: Cancer cells often elicit a higher glycolytic rate than normal cells, supporting the development of glycolysis inhibitors as therapeutic agents. 2-Deoxyglucose (2-DG) is used in this context due to its ability to compete with glucose. However, many studies do not take into account that 2-DG inhibits not only glycolysis but also N-glycosylation. Since there are limited publications on 2-DG mechanism of action in breast cancer, we studied its effects in breast cancer cell lines to determine the part played by glycolysis inhibition and N-linked glycosylation interference.

METHODS AND RESULTS: 2-Deoxyglucose behaved as an anticancer agent with a similar efficiency on cell number decrease between the hormone-dependent MCF-7 and hormone-independent MDA-MB-231 breast cancer cells. It also interfered with the N-linked glycosylation process in both cell lines as illustrated by the migration profile of the lysosomal-associated membrane protein 2 and calumenin. These results are reinforced by the appearance of an abnormal Man7GlcNAc2 structure both on lipid-linked oligosaccharides and N-linked glycoproteins of 2-DG incubated MDA-MB-231 cells. Besides, 2-DG-induced a transient endoplasmic reticulum stress that was more sustained in MDA-MB-231 cells. Both changes were abrogated by mannose. 2-DG, even in the presence of mannose, decreased glycolysis in both cell lines. Mannose partially reversed the effects of 2-DG on cell numbers with N-linked glycosylation interference accounting for 37 and 47% of 2-DG anti-cancerous effects in MDA-MB-231 and MCF-7 cells, respectively.

CONCLUSION: N-linked glycosylation interference and glycolysis disruption both contribute to the anticancer properties of 2-DG in breast cancer cells.

01Oct/18

Siddeek B, Mauduit C, Simeoni U, Benahmed M

Mutat. Res. 2018 Oct – Dec;778:38-44

Abstract

PMID: 30454681

Paternal exposure to environmental challenges plays a critical role in the offspring’s future health and the transmission of acquired traits through generations. This review summarizes our current knowledge in the new field of epigenomic paternal transmission of health and disease. Epidemiological studies identified that paternal ageing or challenges (imbalanced diets, stress, toxicants, cigarette smoke, alcohol) increased the risk of offspring to develop diseases such as cancer, metabolic, cardiovascular, and neurological diseases. These data were confirmed and deepened in animal models of exposure to challenges including low-protein, low-folate, high-fat diets, exposure to chemicals such as pesticides and herbicides. Even though some toxicants have mutagenic effect on sperm DNA, changes in sperm epigenome seem to be a common thread between different types of challenges. Indeed, epigenetic changes (DNA methylation, chromatin remodeling, small non-coding RNA) in sperm are described as new mechanisms of intergenerational transmission as demonstrated for dioxin, for example. Those epimutations induce dysregulation in genes expression involved in key cellular pathways such as reactive oxygen species and genome stability regulation, in brain-derived neurotrophic factor, calcium and glucocorticoid signaling, and in lipid and glucose metabolism, leading to diseases in offspring. Finally, since each type of environmental challenges has its own signature by inducing epimutations at specific genomic loci, the sperm epigenome might be used as a biomarker in toxicological and risk assessments.

30Sep/18

Jacquel A, Luciano F, Robert G, Auberger P

Int J Mol Sci 2018 Sep;19(10)

Abstract

PMID: 30274374

AMP-activated protein kinase (AMPK) is a heterotrimeric serine/threonine kinase consisting of the arrangement of various α β, and γisoforms that are expressed differently depending on the tissue or the cell lineage. AMPK is one of the major sensors of energy status in mammalian cells and as such plays essential roles in the regulation of cellular homeostasis, metabolism, cell growth, differentiation, apoptosis, and autophagy. AMPK is activated by two upstream kinases, the tumor suppressor liver kinase B1 (LKB1) and the calcium/calmodulin-dependent protein kinase kinase 2 (CAMKK2) through phosphorylation of the kinase on Thr172, leading to its activation. In addition, AMPK inhibits the mTOR pathway through phosphorylation and activation of tuberous sclerosis protein 2 (TSC2) and causes direct activation of unc-51-like autophagy activating kinase 1 (ULK1) via phosphorylation of Ser555, thus promoting initiation of autophagy. Although it is well established that AMPK can control the differentiation of different cell lineages, including hematopoietic stem cells (HSCs), progenitors, and mature hematopoietic cells, the role of AMPK regarding myeloid cell differentiation is less documented. The differentiation of monocytes into macrophages triggered by colony stimulating factor 1 (CSF-1), a process during which both caspase activation (independently of apoptosis induction) and AMPK-dependent stimulation of autophagy are necessary, is one noticeable example of the involvement of AMPK in the physiological differentiation of myeloid cells. The present review focuses on the role of AMPK in the regulation of the physiological and pathological differentiation of myeloid cells. The mechanisms of autophagy induction by AMPK will also be addressed, as autophagy has been shown to be important for differentiation of hematopoietic cells. In addition, myeloid malignancies (myeloid leukemia or dysplasia) are characterized by profound defects in the establishment of proper differentiation programs. Reinduction of a normal differentiation process in myeloid malignancies has thus emerged as a valuable and promising therapeutic strategy. As AMPK seems to exert a key role in the differentiation of myeloid cells, notably through induction of autophagy, we will also discuss the potential to target this pathway as a pro-differentiating and anti-leukemic strategy in myeloid malignancies.

01Sep/18

Raffort J, Chinetti G, Lareyre F

Biochimie 2018 Sep;152:149-154

Abstract

PMID: 30103898

Recent antidiabetic drugs including GLP-1 receptor agonists and DPP-IV inhibitors have demonstrated protective effects in several cardiovascular diseases but their effect in abdominal aortic aneurysm (AAA) is far less known. AAA can be associated with extremely high rates of mortality and pharmacological treatments are still lacking underlining the real need to identify new therapeutic targets. The aim of this review was to summarize current knowledge on the role of GLP-1 pathway in AAA. A systematic literature review was performed and 6 relevant studies (2 clinical and 4 experimental) were included. Experimental studies demonstrated a protective effect of both GLP-1 receptor agonists and DPP-IV inhibitors through targeting the main pathophysiological mechanisms underlying AAA formation. The effects of these drugs in human AAA are still poorly known. In the limelight of clinical and experimental studies, we discuss current limits and future directions.

22Juin/18

Lebeaupin C, Vallée D, Hazari Y, Hetz C, Chevet E, Bailly-Maitre B

J. Hepatol. 2018 Jun;

Abstract

PMID: 29940269

The obesity epidemic is accompanied by a worldwide burden of non-alcoholic fatty liver disease (NAFLD) that manifests from simple steatosis to non-alcoholic steatohepatitis (NASH), possibly evolving into hepatocellular carcinoma (HCC). Although much attention has been focused on NAFLD, its pathogenesis remains largely obscure. The hallmark of NAFLD is the hepatic accumulation of lipids subsequently leading to cellular stress and hepatic injury, which eventually results in chronic liver disease. Abnormal lipid accumulation often coincides with insulin resistance in steatotic livers and is associated with perturbed endoplasmic reticulum (ER) proteostasis in hepatocytes. In response to chronic ER stress, an adaptive signaling pathway known as the Unfolded Protein Response (UPR) is triggered initially to restore ER proteostasis. The UPR can be accountable for inflammation, inflammasome activation and, in the case of non-resolvable ER stress, for the death of hepatocytes. Experimental data suggest that the UPR influences hepatic tumor development, aggressiveness and response to treatment, offering novel therapeutic avenues. Herein, we provide an overview of the evidence linking ER stress to NAFLD and discuss possible points of intervention.

22Juin/18

Castela E, Tulic MK, Rozières A, Bourrat E, Nicolas JF, Kanitakis J, Vabres P, Bessis D, Mazereeuw J, Morice-Picard F, Baty D, Berard F, Lacour JP, Passeron T, Chiaverini C

Br. J. Dermatol. 2018 Jun;

Abstract

PMID: 29932457

BACKGROUND: Epidermolysis bullosa simplex generalized severe is a genetic disorder caused by mutation in KRT5 or KRT14 genes. Usually considered as a mechanical disease, recent data argue for additional inflammatory mechanisms.

OBJECTIVES: The aim of this study was to assess the inflammation in the skin of patients with EBS.

METHODS: A first immunohistochemical retrospective study was performed on frozen skin samples from 17 EBS-gen sev patients. A second multicenter prospective study was conducted on 10 patients with severe EBS-gen sev. Blister fluid and epidermis were processed for immunochemistry analysis and quantitative real time PCR. Cytokine expression was analyzed in blister fluid and compared with controls.

RESULTS: Histological analysis showed a constant dermal perivascular CD4+ lymphocytes infiltrate in skin biopsies of blister (n=17) as well as in rubbed skin (n=5), an epidermal infiltration of neutrophils and eosinophils in 70% of cases and an increased immunostaining for CXCL9 and CXCL10 in blistering skin. High levels of Th17 cytokines were detected in lesional skin. Three adult patients with EBS-gen sev were treated with apremilast with a dramatic improvement of skin blistering and good tolerance.

CONCLUSION: Our study demonstrates the importance of inflammation in EBS-gen sev patients and underlines the key role for Th17 cells in its pathogenesis. In addition, this study provides promising new therapeutic approaches for this disabling disorder. This article is protected by copyright. All rights reserved.

18Juin/18

Siddeek B, Mauduit C, Yzydorczyk C, Benahmed M, Simeoni U

J Dev Orig Health Dis 2018 Jun;:1-17

Abstract

PMID: 29909803

Epidemiological and experimental observations tend to prove that environment, lifestyle or nutritional challenges influence heart functions together with genetic factors. Furthermore, when occurring during sensitive windows of heart development, these environmental challenges can induce an ‘altered programming’ of heart development and shape the future heart disease risk. In the etiology of heart diseases driven by environmental challenges, epigenetics has been highlighted as an underlying mechanism, constituting a bridge between environment and heart health. In particular, micro-RNAs which are involved in each step of heart development and functions seem to play a crucial role in the unfavorable programming of heart diseases. This review describes the latest advances in micro-RNA research in heart diseases driven by early exposure to challenges and discusses the use of micro-RNAs as potential targets in the reversal of the pathophysiology.

01Juin/18

Marzag H, Zerhouni M, Tachallait H, Demange L, Robert G, Bougrin K, Auberger P, Benhida R

Bioorg. Med. Chem. Lett. 2018 Jun;28(10):1931-1936

Abstract

PMID: 29655981

The C-aryl-ribosyles are of utmost interest for the development of antiviral and anticancer agents. Even if several synthetic pathways have been disclosed for the preparation of these nucleosides, a direct, few steps and modular approaches are still lacking. In line with our previous efforts, we report herein a one step – eco-friendly β-ribosylation of aryles and heteroaryles through a direct Friedel-Craft ribosylation mediated by bismuth triflate, Bi(OTf). The resulting carbohydrates have been functionalized by cross-coupling reactions, leading to a series of new C-aryl-nucleosides (32 compounds). Among them, we observed that 5d exerts promising anti-proliferative effects against two human Chronic Myeloid Leukemia (CML) cell lines, both sensitive (K562-S) or resistant (K562-R) to imatinib, the « gold standard of care » used in this pathology. Moreover, we demonstrated that 5d kills CML cells by a non-conventional mechanism of cell death.

01Juin/18

Yvan-Charvet L, Cariou B

Curr. Opin. Lipidol. 2018 Jun;29(3):246-258

Abstract

PMID: 29553996

PURPOSE OF REVIEW: Cardiovascular diseases (CVD) are the leading cause of death worldwide with over 17 million deaths every year and represent a major public health challenge. The last decade has seen the emergence of novel antiatherogenic therapies.

RECENT FINDINGS: Despite intensive lipid and blood pressure interventions, the burden of CVD is expected to markedly progress because of the global aging of the population and increasing exposure to detrimental lifestyle-related risk. Epidemiologic and genetic studies helped to better apprehend the biology of atherosclerosis and allowed pharmaceutical innovation and recent translational successes. This includes the development of novel lipid and glucose-lowering therapies and the leverage of anti-inflammatory therapies.

SUMMARY: Here, we discuss promises and expectations of emerging scientific and pharmaceutical innovations and translational successes to meet the global therapeutic demand.

11Mai/18

Viaud M, Ivanov S, Vujic N, Duta-Mare M, Aira LE, Barouillet T, Garcia E, Orange F, Dugail I, Hainault I, Stehlik C, Marchetti S, Boyer L, Guinamard R, Foufelle F, Bochem A, Hovingh KG, Thorp EB, Gautier EL, Kratky D, Dasilva-Jardine P, Yvan-Charvet L

Circ. Res. 2018 May;122(10):1369-1384

Abstract

PMID: 29523554

RATIONALE: Macrophages face a substantial amount of cholesterol after the ingestion of apoptotic cells, and the LIPA (lysosomal acid lipase) has a major role in hydrolyzing cholesteryl esters in the endocytic compartment.

OBJECTIVE: Here, we directly investigated the role of LIPA-mediated clearance of apoptotic cells both in vitro and in vivo.

METHODS AND RESULTS: We show that LIPA inhibition causes a defective efferocytic response because of impaired generation of 25-hydroxycholesterol and 27-hydroxycholesterol. Reduced synthesis of 25-hydroxycholesterol after LIPA inhibition contributed to defective mitochondria-associated membrane leading to mitochondrial oxidative stress-induced NLRP3 (NOD-like receptor family, pyrin domain containing) inflammasome activation and caspase-1-dependent Rac1 (Ras-related C3 botulinum toxin substrate 1) degradation. A secondary event consisting of failure to appropriately activate liver X receptor-mediated pathways led to mitigation of cholesterol efflux and apoptotic cell clearance. In mice, LIPA inhibition caused defective clearance of apoptotic lymphocytes and stressed erythrocytes by hepatic and splenic macrophages, culminating in splenomegaly and splenic iron accumulation under hypercholesterolemia.

CONCLUSIONS: Our findings position lysosomal cholesterol hydrolysis as a critical process that prevents metabolic inflammation by enabling efficient macrophage apoptotic cell clearance.

09Mai/18

Rouaud F, Hamouda-Tekaya N, Cerezo M, Abbe P, Zangari J, Hofman V, Ohanna M, Mograbi B, El-Hachem N, Benfodda Z, Lebeau A, Tulic MK, Hofman P, Bertolotto C, Passeron T, Annicotte JS, Ballotti R, Rocchi S

Cell Death Dis 2018 May;9(5):527

Abstract

PMID: 29743521

Melanoma is one of the most lethal cancers when it reaches a metastatic stage. Despite advancements in targeted therapies (BRAF inhibitors) or immunotherapies (anti-CTLA-4 or anti-PD1), most patients with melanoma will need additional treatment. Thus, there is an urgent need to develop new therapeutical approaches to bypass resistance and achieve more prolonged responses. In this context, we were interested in E2F1, a transcription factor that plays a major role in the control of cell cycle under physiological and pathological conditions. Here we confirmed that E2F1 is highly expressed in melanoma cells. Inhibition of E2F1 activity further increased melanoma cell death and senescence, both in vitro and in vivo. Moreover, blocking E2F1 also induced death of melanoma cells resistant to BRAF inhibitors. In conclusion, our studies suggest that targeting the E2F1 signaling pathway may be therapeutically relevant for melanoma.

27Avr/18

Didier R, Mallavialle A, Ben Jouira R, Domdom MA, Tichet M, Auberger P, Luciano F, Ohanna M, Tartare-Deckert S, Deckert M

Mol. Cancer Ther. 2018 Apr;

Abstract

PMID: 29703842

Advanced cutaneous melanoma is one of the most challenging cancers to treat because of its high plasticity, metastatic potential and resistance to treatment. New targeted therapies and immunotherapies have shown remarkable clinical efficacy. However, such treatments are limited to a subset of patients and relapses often occur, warranting validation of novel targeted therapies. Post-translational modification of proteins by ubiquitin coordinates essential cellular functions, including ubiquitin-proteasome system (UPS) function and protein homeostasis. Deubiquitinating enzymes (DUBs) have been associated to multiple diseases, including cancer. However, their exact involvement in melanoma development and therapeutic resistance remains poorly understood. Using a DUB trap assay to label cellular active DUBs, we have observed an increased activity of the proteasome-associated DUB, USP14 (Ubiquitin-specific peptidase 14) in melanoma cells compared to melanocytes. Our survey of public gene expression databases indicates that high expression of USP14 correlates with melanoma progression and with a poorer survival rate in metastatic melanoma patients. Knockdown or pharmacological inhibition of USP14 dramatically impairs viability of melanoma cells irrespective of the mutational status of BRAF, NRAS or TP53 and their transcriptional cell state, and overcomes resistance to MAPK-targeting therapies both in vitro and in human melanoma xenografted mice. At the molecular level, we find that inhibition of USP14 rapidly triggers accumulation of poly-ubiquitinated proteins and chaperones, mitochondrial dysfunction, ER stress, and a ROS production leading to a caspase-independent cell death. Our results provide a rationale for targeting the proteasome-associated DUB USP14 to treat and combat melanomas.

06Avr/18

Mahtal N, Brewee C, Pichard S, Visvikis O, Cintrat JC, Barbier J, Lemichez E, Gillet D

ChemMedChem 2018 Apr;13(7):754-761

Abstract

PMID: 29359495

Cytotoxic necrotizing factor 1 (CNF1) is a toxin produced by pathogenic strains of Escherichia coli responsible for extra-intestinal infections. CNF1 deamidates Rac1, thereby triggering its permanent activation and worsening inflammatory reactions. Activated Rac1 is prone to proteasomal degradation. There is no targeted therapy against CNF1, despite its clinical relevance. In this work we developed a fluorescent cell-based immunoassay to screen for inhibitors of CNF1-induced Rac1 degradation among 1120 mostly approved drugs. Eleven compounds were found to prevent CNF1-induced Rac1 degradation, and five also showed a protective effect against CNF1-induced multinucleation. Finally, lasalocid, monensin, bepridil, and amodiaquine protected cells from both diphtheria toxin and CNF1 challenges. These data highlight the potential for drug repurposing to fight several bacterial infections and Rac1-based diseases.

03Avr/18

Rubio-Patiño C, Bossowski JP, De Donatis GM, Mondragón L, Villa E, Aira LE, Chiche J, Mhaidly R, Lebeaupin C, Marchetti S, Voutetakis K, Chatziioannou A, Castelli FA, Lamourette P, Chu-Van E, Fenaille F, Avril T, Passeron T, Patterson JB, Verhoeyen E, Bailly-Maitre B, Chevet E, Ricci JE

Cell Metab. 2018 Apr;27(4):828-842.e7

Abstract

PMID: 29551590

Dietary restriction (DR) was shown to impact on tumor growth with very variable effects depending on the cancer type. However, how DR limits cancer progression remains largely unknown. Here, we demonstrate that feeding mice a low-protein (Low PROT) isocaloric diet but not a low-carbohydrate (Low CHO) diet reduced tumor growth in three independent mouse cancer models. Surprisingly, this effect relies on anticancer immunosurveillance, as depleting CD8 T cells, antigen-presenting cells (APCs), or using immunodeficient mice prevented the beneficial effect of the diet. Mechanistically, we established that a Low PROT diet induces the unfolded protein response (UPR) in tumor cells through the activation of IRE1α and RIG1 signaling, thereby resulting in cytokine production and mounting an efficient anticancer immune response. Collectively, our data suggest that a Low PROT diet induces an IRE1α-dependent UPR in cancer cells, enhancing a CD8-mediated T cell response against tumors.

01Avr/18

Brakni R, Ali Ahmed M, Burger P, Schwing A, Michel G, Pomares C, Hasseine L, Boyer L, Fernandez X, Landreau A, Michel T

Chem. Biodivers. 2018 Apr;15(4):e1800031

Abstract

PMID: 29505125

Lichens are complex symbiotic organisms able to produce a vast array of compounds. The Algerian lichen diversity has only prompted little interest even given the 1085 species listed. Herein, the chemodiversity of four Algerian lichens including Cladonia rangiformis, Ramalina farinaceae, R. fastigiata, and Roccella phycopsis was investigated. A dereplication strategy, using ultra high performance liquid chromatography-high resolution-electrospray ionization-mass spectrometry (UHPLC-HRMS/MS), was carried out for a comprehensive characterization of their substances including phenolics, depsides, depsidones, depsones, dibenzofurans, and aliphatic acids. Some known compounds were identified for the first time in some species. Additionally, the lichenic extracts were evaluated for their antifungal and antimicrobial activities on human pathogenic strains (Candida albicans, C. glabrata, Aspergillus fumigatus, Staphylococcus aureus, and Escherichia coli). Cyclohexane extracts were found particularly active against human pathogenic fungi with MIC values ranging from 8 to 62.5 μg/mL, without cytotoxicity. This study highlights the therapeutic and prophylactic potential of lichenic extracts as antibacterial and antifungal agents.

01Avr/18

Ivanov S, Merlin J, Lee MKS, Murphy AJ, Guinamard RR

Atherosclerosis 2018 Apr;271:102-110

Abstract

PMID: 29482037

The increasing incidence of obesity and its socio-economical impact is a global health issue due to its associated co-morbidities, namely diabetes and cardiovascular disease [1-5]. Obesity is characterized by an increase in adipose tissue, which promotes the recruitment of immune cells resulting in low-grade inflammation and dysfunctional metabolism. Macrophages are the most abundant immune cells in the adipose tissue of mice and humans. The adipose tissue also contains other myeloid cells (dendritic cells (DC) and neutrophils) and to a lesser extent lymphocyte populations, including T cells, B cells, Natural Killer (NK) and Natural Killer T (NKT) cells. While the majority of studies have linked adipose tissue macrophages (ATM) to the development of low-grade inflammation and co-morbidities associated with obesity, emerging evidence suggests for a role of other immune cells within the adipose tissue that may act in part by supporting macrophage homeostasis. In this review, we summarize the current knowledge of the functions ATMs, DCs and B cells possess during steady-state and obesity.

07Mar/18

El-Hachem N, Habel N, Naiken T, Bzioueche H, Cheli Y, Beranger GE, Jaune E, Rouaud F, Nottet N, Reinier F, Gaudel C, Colosetti P, Bertolotto C, Ballotti R

Cell Death Differ. 2018 Mar;

Abstract

PMID: 29515254

HACE1 is an E3 ubiquitin ligase described as a tumour suppressor because HACE1-knockout mice develop multi-organ, late-onset cancers and because HACE1 expression is lost in several neoplasms, such as Wilms’ tumours and colorectal cancer. However, a search of public databases indicated that HACE1 expression is maintained in melanomas. We demonstrated that HACE1 promoted melanoma cell migration and adhesion in vitro and was required for mouse lung colonisation by melanoma cells in vivo. Transcriptomic analysis of HACE1-depleted melanoma cells revealed an inhibition of ITGAV and ITGB1 as well changes in other genes involved in cell migration. We revealed that HACE1 promoted the K27 ubiquitination of fibronectin and regulated its secretion. Secreted fibronectin regulated ITGAV and ITGB1 expression, as well as melanoma cell adhesion and migration. Our findings disclose a novel molecular cascade involved in the regulation of fibronectin secretion, integrin expression and melanoma cell adhesion. By controlling this cascade, HACE1 displays pro-tumoural properties and is an important regulator of melanoma cell invasive properties.

01Mar/18

Ohanna M, Cerezo M, Nottet N, Bille K, Didier R, Beranger G, Mograbi B, Rocchi S, Yvan-Charvet L, Ballotti R, Bertolotto C

Genes Dev. 2018 03;32(5-6):448-461

Abstract

PMID: 29567766

In BRAF melanoma cells, a global metabolomic analysis discloses a decrease in nicotinamide adenine dinucleotide (NAD) levels upon PLX4032 treatment that is conveyed by a STAT5 inhibition and a transcriptional regulation of the nicotinamide phosphoribosyltransferase (NAMPT) gene. NAMPT inhibition decreases melanoma cell proliferation both in vitro and in vivo, while forced NAMPT expression renders melanoma cells resistant to PLX4032. NAMPT expression induces transcriptomic and epigenetic reshufflings that steer melanoma cells toward an invasive phenotype associated with resistance to targeted therapies and immunotherapies. Therefore, NAMPT, the key enzyme in the NAD salvage pathway, appears as a rational target in targeted therapy-resistant melanoma cells and a key player in phenotypic plasticity of melanoma cells.

20Fév/18

Ruggiero C, Doghman-Bouguerra M, Ronco C, Benhida R, Rocchi S, Lalli E

Mol. Cell. Endocrinol. 2018 Feb;

Abstract

PMID: 29474877

Many types of cancer cells present constitutively activated ER stress pathways because of their significant burden of misfolded proteins coded by mutated and rearranged genes. Further increase of ER stress by pharmacological intervention may shift the balance towards cell death and can be exploited therapeutically. Recent studies have shown that an important component in the mechanism of action of mitotane, the only approved drug for the medical treatment of adrenocortical carcinoma (ACC), is represented by activation of ER stress through inhibition of the SOAT1 enzyme and accumulation of toxic lipids. Here we show that HA15, a novel inhibitor of the essential ER chaperone GRP78/BiP, inhibits ACC H295R cell proliferation and steroidogenesis and is able to synergize with mitotane action. These results suggest that convergent activation of ER stress pathways by drugs acting via different mechanisms represents a valuable therapeutic option for ACC.

19Fév/18

Lebeaupin C, Vallée D, Rousseau D, Patouraux S, Bonnafous S, Adam G, Luciano F, Luci C, Anty R, Iannelli A, Marchetti S, Kroemer G, Lacas-Gervais S, Tran A, Gual P, Bailly-Maitre B

Hepatology 2018 Feb;

Abstract

PMID: 29457838

Endoplasmic reticulum (ER) stress is activated in nonalcoholic fatty liver disease (NAFLD), raising the possibility that ER stress-dependent metabolic dysfunction, inflammation, and cell death underlie the transition from steatosis to steatohepatitis (nonalcoholic steatohepatitis; NASH). B-cell lymphoma 2 (BCL2)-associated X protein (Bax) inhibitor-1 (BI-1), a negative regulator of the ER stress sensor, inositol-requiring enzyme 1 alpha (IRE1α), has yet to be explored in NAFLD as a hepatoprotective agent. We hypothesized that the genetic ablation of BI-1 would render the liver vulnerable to NASH because of unrestrained IRE1α signaling. ER stress was induced in wild-type and BI-1 mice acutely by tunicamycin (TM) injection (1 mg/kg) or chronically by high-fat diet (HFD) feeding to determine NAFLD phenotype. Livers of TM-treated BI-1 mice showed IRE1α-dependent NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation, hepatocyte death, fibrosis, and dysregulated lipid homeostasis that led to liver failure within a week. The analysis of human NAFLD liver biopsies revealed BI-1 down-regulation parallel to the up-regulation of IRE1α endoribonuclease (RNase) signaling. In HFD-fed BI-1 mice that presented NASH and type 2 diabetes, exaggerated hepatic IRE1α, X-box binding protein 1 (XBP1), and C/EBP homologous protein (CHOP) expression was linked to activated NLRP3 inflammasome and caspase-1/-11. Rises in interleukin (IL)-1β, IL-6, monocyte chemoattractant protein 1 (MCP1), chemokine (C-X-C motif) ligand 1 (CXCL1), and alanine transaminase (ALT)/aspartate transaminase (AST) levels revealed significant inflammation and injury, respectively. Pharmacological inhibition of IRE1α RNase activity with the small molecules, STF-083010 or 4μ8c, was evaluated in HFD-induced NAFLD. In BI-1 mice, either treatment effectively counteracted IRE1α RNase activity, improving glucose tolerance and rescuing from NASH. The hepatocyte-specific role of IRE1α RNase activity in mediating NLRP3 inflammasome activation and cell death was confirmed in primary mouse hepatocytes by IRE1α axis knockdown or its inhibition with STF-083010 or 4μ8c.

CONCLUSION: Targeting IRE1α-dependent NLRP3 inflammasome signaling with pharmacological agents or by BI-1 may represent a tangible therapeutic strategy for NASH. (Hepatology 2018).

16Fév/18

Dufies M, Ambrosetti D, Boulakirba S, Calleja A, Savy C, Furstoss N, Zerhouni M, Parola J, Aira-Diaz L, Marchetti S, Orange F, Lacas-Gervais S, Luciano F, Jacquel A, Robert G, Pagès G, Auberger P

Oncotarget 2018 Feb;9(13):10920-10933

Abstract

PMID: 29541386

Polo-like kinases (Plks) define a highly conserved family of Ser/Thr kinases with crucial roles in the regulation of cell division. Here we show that Plk1 is cleaved by caspase 3, but not by other caspases in different hematopoietic cell lines treated with competitive inhibitors of the ATP-binding pocket of Plk1. Intriguingly, Plk1 was not cleaved in cells treated with Rigosertib, a non-competitive inhibitor of Plk1, suggesting that binding of the inhibitor to the ATP binding pocket of Plk1 triggers a conformational change and unmasks a cryptic caspase 3 cleavage site on the protein. Cleavage occurs after Asp-404 in a DYSD/K sequence and separates the kinase domain from the two PBDs of Plk1. All Plk1 inhibitors triggered G2/M arrest, activation of caspases 2 and 3, polyploidy, multiple nuclei and mitotic catastrophe, albeit at higher concentrations in the case of Rigosertib. Upon BI-2536 treatment, Plk1 cleavage occurred only in the cytosolic fraction and cleaved Plk1 accumulated in this subcellular compartment. Importantly, the cleaved N-Terminal fragment of Plk1 exhibited a higher enzymatic activity than its non-cleaved counterpart and accumulated into the cytoplasm conversely to the full length and the C-Terminal Plk1 fragments that were found essentially into the nucleus. Finally, the DYSD/K cleavage site was highly conserved during evolution from to human. In conclusion, we described herein for the first time a specific cleavage of Plk1 by caspase 3 following treatment of cancer cells with ATP-competitive inhibitors of Plk1.

01Fév/18

Imbert V, Nebout M, Mary D, Endou H, Wempe MF, Supuran CT, Winum JY, Peyron JF

Leuk. Lymphoma 2018 Feb;59(2):460-468

Abstract

PMID: 28641473

Cancer cells reprogram their metabolism to optimize their growth and proliferation in the host microenvironment. For this purpose, they enhance the uptake of extracellular nutrients and deal with the metabolic waste products through the overexpression of numerous membrane proteins including amino-acid transporters (LAT1) and acid-base regulating enzymes, such as carbonic anhydrases (CAs). Here we describe the anti-tumoral effects of a new class of CAXII inhibitors, the glycosyl coumarins on T-ALL/LL cells. These effects appeared to be mediated through inhibition of mTOR/Akt pathway and c-myc downregulation. Interestingly, we show that the combined targeting of amino acid fluxes and pH regulators provides a promising therapeutic strategy in the future of T-ALL/LL management.

10Jan/18

Boulakirba S, Pfeifer A, Mhaidly R, Obba S, Goulard M, Schmitt T, Chaintreuil P, Calleja A, Furstoss N, Orange F, Lacas-Gervais S, Boyer L, Marchetti S, Verhoeyen E, Luciano F, Robert G, Auberger P, Jacquel A

Sci Rep 2018 Jan;8(1):256

Abstract

PMID: 29321503

CSF-1 and IL-34 share the CSF-1 receptor and no differences have been reported in the signaling pathways triggered by both ligands in human monocytes. IL-34 promotes the differentiation and survival of monocytes, macrophages and osteoclasts, as CSF-1 does. However, IL-34 binds other receptors, suggesting that differences exist in the effect of both cytokines. In the present study, we compared the differentiation and polarization abilities of human primary monocytes in response to CSF-1 or IL-34. CSF-1R engagement by one or the other ligands leads to AKT and caspase activation and autophagy induction through expression and activation of AMPK and ULK1. As no differences were detected on monocyte differentiation, we investigated the effect of CSF-1 and IL-34 on macrophage polarization into the M1 or M2 phenotype. We highlighted a striking increase in IL-10 and CCL17 secretion in M1 and M2 macrophages derived from IL-34 stimulated monocytes, respectively, compared to CSF-1 stimulated monocytes. Variations in the secretome induced by CSF-1 or IL-34 may account for their different ability to polarize naïve T cells into Th1 cells. In conclusion, our findings indicate that CSF-1 and IL-34 exhibit the same ability to induce human monocyte differentiation but may have a different ability to polarize macrophages.

01Jan/18

Thongon N, Zucal C, D’Agostino VG, Tebaldi T, Ravera S, Zamporlini F, Piacente F, Moschoi R, Raffaelli N, Quattrone A, Nencioni A, Peyron JF, Provenzani A

Cancer Metab 2018;6:1

Abstract

PMID: 29541451

Background: Inhibitors of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in NAD biosynthesis from nicotinamide, exhibit anticancer effects in preclinical models. However, continuous exposure to NAMPT inhibitors, such as FK866, can induce acquired resistance.

Methods: We developed FK866-resistant CCRF-CEM (T cell acute lymphoblastic leukemia) and MDA MB231 (breast cancer) models, and by exploiting an integrated approach based on genetic, biochemical, and genome wide analyses, we annotated the drug resistance mechanisms.

Results: Acquired resistance to FK866 was independent of NAMPT mutations but rather was based on a shift towards a glycolytic metabolism and on lactate dehydrogenase A (LDHA) activity. In addition, resistant CCRF-CEM cells, which exhibit high quinolinate phosphoribosyltransferase (QPRT) activity, also exploited amino acid catabolism as an alternative source for NAD production, becoming addicted to tryptophan and glutamine and sensitive to treatment with the amino acid transport inhibitor JPH203 and with l-asparaginase, which affects glutamine exploitation. Vice versa, in line with their low QPRT expression, FK866-resistant MDA MB231 did not rely on amino acids for their resistance phenotype.

Conclusions: Our study identifies novel mechanisms of resistance to NAMPT inhibition, which may be useful to design more rational strategies for targeting cancer metabolism.

01Jan/18

Jaune E, Rocchi S

Front Endocrinol (Lausanne) 2018;9:472

Abstract

PMID: 30186236

Metformin is the most common biguanide used in the treatment of diabetes, with 120 million treated patients worldwide. Metformin decreases hyperglycemia without inducing hypoglycemia in diabetic patients and is very well tolerated. The principal effects of metformin are to decrease hepatic gluconeogenesis and increase glucose absorption by skeletal muscles. These effects are primarily due to metformin’s action on mitochondria, which requires the activation of metabolic checkpoint AMP-activated protein kinase (AMPK). AMPK is implicated in several pathways, and following metformin activation, it decreases protein synthesis and cell proliferation. Many studies have examined the role of metformin in the regulation of cancer cells, particularly its effects on cancer cell proliferation and cell death. Encouraging results have been obtained in different types of cancers, including prostate, breast, lung, and skin cancers (melanoma). Furthermore, many retrospective epidemiological studies in diabetes patients have shown that metformin treatment decreased the risk of cancers compared with other antidiabetic treatments. In this review, we will discuss the effects of metformin on melanoma cells. Together, our novel data demonstrate the importance of developing metformin and new biguanide-derived compounds as potential treatments against a number of different cancers, particularly melanoma.

01Jan/18

Biondani G, Peyron JF

Front Endocrinol (Lausanne) 2018;9:446

Abstract

PMID: 30147674

Metformin, a widely used anti-diabetic molecule, has attracted a strong interest in the last 10 years as a possible new anti-cancer molecule. Metformin acts by interfering with mitochondrial respiration, leading to an activation of the AMPK tumor-suppressive pathway to promote catabolic-energy saving reactions and block anabolic ones that are associated with abnormal cell proliferation. Metformin also acts at the organism level. In type 2 diabetes patients, metformin reduces hyperglycemia and increases insulin sensitivity by enhancing insulin-stimulated glucose uptake in muscles, liver, and adipose tissue and by reducing glucose output by the liver. Lowering insulin and insulin-like growth factor 1 (IGF-1) levels that stimulate cancer growth could be important features of metformin’s mode of action. Despite continuous progress in treatments with the use of targeted therapies and now immunotherapies, acute leukemias are still of very poor prognosis for relapse patients, demonstrating an important need for new treatments deriving from the identification of their pathological supportive mechanisms. In the last decade, it has been realized that if cancer cells modify and reprogram their metabolism to feed their intense biochemical needs associated with their runaway proliferation, they develop metabolic addictions that could represent attractive targets for new therapeutic strategies that intend to starve and kill cancer cells. This Mini Review explores the anti-leukemic potential of metformin and its mode of action on leukemia metabolism.

01Jan/18

Ricci JE, Chiche J

Front Oncol 2018;8:556

Abstract

PMID: 30564554

Metabolism is a wide and general term that refers to any intracellular pathways the cell utilizes in order to satisfy its energetic demand and to support cell viability and/or division. Along with phenotypic changes, all mammalian cells including immune cells modulate their metabolic program in order to reach their effector functions. Exacerbated metabolism and metabolic flexibility are also hallmarks of tumor initiation and of tumor cell progression in a complex tumor microenvironment. Metabolic reprogramming is mainly directed by the serine/threonine kinase mTOR (mammalian target of rapamycin). mTOR exists in two structurally and functionally distinct complexes, mTORC1 and mTORC2 that coordinate environmental signals and metabolic/anabolic pathways to provide macromolecules and energy needed for survival and growth. Activation of mTORC1 is required during development, differentiation and activation of immune cells. Aberrant and persistent activation of mTORC1 is often observed in malignant B cells such as Non-Hodgkin’s (NH) B-cell lymphomas. Here, we review recent insights on cell metabolism and on basic mechanisms of mTORC1 regulation and metabolic functions. We highlight the distinct mechanisms driving mTORC1 activation in the three most-common types of NH B-cell lymphomas (Diffuse Large B Cell Lymphomas, Follicular Lymphomas, and Mantle Cell Lymphomas), for which the first generation of mTORC1 inhibitors (rapalogs) have been extensively evaluated in preclinical and clinical settings. Finally, we discuss the reasons for limited clinical success of this therapy and focus on potential therapeutic strategies targeting metabolic pathways, upstream and downstream of mTORC1, that can be combined to rapalogs in order to improve patient’s outcome.

01Jan/18

Stunault MI, Bories G, Guinamard RR, Ivanov S

Mediators Inflamm. 2018;2018:2426138

Abstract

PMID: 30647530

Monocyte and macrophage diversity is evidenced by the modulation of cell surface markers and differential production of soluble mediators. These immune cells play key roles in controlling tissue homeostasis, infections, and excessive inflammation. Macrophages remove dead cells in a process named efferocytosis, contributing to the healthy tissue maintenance. Recently, it became clear that the main macrophage functions are under metabolic control. Modulation of glucose, fatty acid, and amino acid metabolism is associated with various macrophage activations in response to external stimuli. Deciphering these metabolic pathways provided critical information about macrophage functions.

01Nov/17

Ganda A, Yvan-Charvet L, Zhang Y, Lai EJ, Regunathan-Shenk R, Hussain FN, Avasare R, Chakraborty B, Febus AJ, Vernocchi L, Lantigua R, Wang Y, Shi X, Hsieh J, Murphy AJ, Wang N, Bijl N, Gordon KM, de Miguel MH, Singer JR, Hogan J, Cremers S, Magnusson M, Melander O, Gerszten RE, Tall AR

J. Mol. Cell. Cardiol. 2017 Nov;112:114-122

Abstract

PMID: 28478047

BACKGROUND: Patients with chronic kidney disease (CKD) experience high rates of atherosclerotic cardiovascular disease and death that are not fully explained by traditional risk factors. In animal studies, defective cellular cholesterol efflux pathways which are mediated by the ATP binding cassette transporters ABCA1 and ABCG1 are associated with accelerated atherosclerosis. We hypothesized that cholesterol efflux in humans would vary in terms of cellular components, with potential implications for cardiovascular disease.

METHODS: We recruited 120 CKD patients (eGFR<30mL/min/1.73m(2)) and 120 control subjects (eGFR ≥60mL/min/1.73m(2)) in order to measure cholesterol efflux using either patients' HDL and THP-1 macrophages or patients' monocytes and a flow cytometry based cholesterol efflux assay. We also measured cell-surface levels of the common β subunit of the IL-3/GM-CSF receptor (IL-3Rβ) which has been linked to defective cholesterol homeostasis and may promote monocytosis. In addition, we measured plasma inflammatory cytokines and plasma metabolite profiles.

RESULTS: There was a strong positive correlation between cell-surface IL-3Rβ levels and monocyte counts in CKD (P<0.001). ABCA1 mRNA was reduced in CKD vs. control monocytes (P<0.05), across various etiologies of CKD. Cholesterol efflux to apolipoprotein A1 was impaired in monocytes from CKD patients with diabetic nephropathy (P<0.05), but we found no evidence for a circulating HDL-mediated defect in cholesterol efflux in CKD. Profiling of plasma metabolites showed that medium-chain acylcarnitines were both independently associated with lower levels of cholesterol transporter mRNA in CKD monocytes at baseline (P<0.05), and with cardiovascular events in CKD patients after median 2.6years of follow-up.

CONCLUSIONS: Cholesterol efflux in humans varies in terms of cellular components. We report a cellular defect in ABCA1-mediated cholesterol efflux in monocytes from CKD patients with diabetic nephropathy. Unlike several traditional risk factors for atherosclerotic cardiovascular disease, plasma metabolites inversely associated with endogenous cholesterol transporters predicted cardiovascular events in CKD patients. (Funded by the National Institute of Diabetes and Digestive and Kidney DiseasesK23DK097288 and others.).

01Nov/17

Sans A, Bailly L, Anty R, Sielezenef I, Gugenheim J, Tran A, Gual P, Iannelli A

Obes Surg 2017 Nov;27(11):2940-2949

Abstract

PMID: 28550439

BACKGROUND: In this study, we explored in a prospective cohort of morbidly obese women undergoing laparoscopic Roux-en-Y gastric bypass (LRYGP) correlations between baseline anthropometrics, metabolic parameters, resting energy expenditure (REE), body composition, and 1-year % excess body mass index loss (%EBMIL). We also investigated risk factors for insufficient %EBMIL.

METHODS: One hundred three consecutive women were prospectively evaluated at baseline (age 40.6 ± 11.2, weight 113.9 kg ± 15.3, BMI 43.3 ± 4.9 kg/m(2)) and 1 year after LRYGP. Weight, excess weight, brachial circumference, waist circumference, fat mass (FM) and fat-free mass (FFM) (measured with bioelectrical impedance analysis), REE, inflammation, insulin resistance, and lipid disturbances were determined before and 1 year after LRYGP.

RESULTS: At 1 year, mean weight loss was 39.8 kg ± 11.7 and mean EBMIL was 15.2 kg/m(2) ± 4.2. Mean %EBMIL was 86% ± 21% (range 30-146%). Baseline brachial circumference, waist circumference and triceps skinfold thickness decreased significantly at 1 year (P < 0.001). Blood glucose and insulin levels, HDL cholesterol, LDL cholesterol, triglycerides, and CRP also decreased significantly (P < 0.001). The mean loss of initial FFM and FM was 9.1 kg ± 8.2 (15%) and 30.7 kg ± 11.8 (53%), respectively. REE on body weight ratio (REE/BW) increased from 15.3 kcal/kg ± 2.8 to 18.4 kcal/kg ± 2.5 (p < 0.0001) and REE on FFM ratio decreased from 31.2 to 28.7 kcal/day/kg (p < 0.001). Preoperative waist circumference (r = -0.3; P < 0.001), blood glucose level (r = -0.37; P < 0.001), and CRP (r = -0.28; P = 0.004) were negatively correlated with EBMIL% 1 year after surgery. Among baseline body composition parameters, only preoperative FM was negatively correlated with %EBMIL (r = -0.23; p = 0.02). One year after surgery FM change was negatively correlated with EBMIL% (r = -0.49; P < 0.001) while FFM/BW ratio was positively correlated with %EBMIL (r = 0.71; P < 0.001). Increase in REE/BW at 1 year was positively correlated with %EBMIL (r = 0.47; p < 0.001). On multivariate analysis, baseline blood glucose level (OR = 1.77; CI 95%: [1.3-2.4]) was the only predictive factor of EBMIL <60% at 1 year.

CONCLUSION: LRYGB has beneficial effects on clinical, biological parameters, and body composition. Increasing the proportion of FFM on total BW and REE/BW is associated with better results in terms of weight loss. Baseline glucose level may be helpful in identifying poor responders to LRYGBP.

TRIAL REGISTRATION: NCT02820285y ( https://clinicaltrials.gov/ct2/show/NCT02820285?term=Characterization+of+Immune+Semaphorin+in+Non-Alcoholic+Fatty+Liver+Disease+and+NASH&rank=1 ).

01Nov/17

Gilot D, Migault M, Bachelot L, Journé F, Rogiers A, Donnou-Fournet E, Mogha A, Mouchet N, Pinel-Marie ML, Mari B, Montier T, Corre S, Gautron A, Rambow F, El Hajj P, Ben Jouira R, Tartare-Deckert S, Marine JC, Felden B, Ghanem G, Galibert MD

Nat. Cell Biol. 2017 Nov;19(11):1348-1357

Abstract

PMID: 28991221

Competition among RNAs to bind miRNA is proposed to influence biological systems. However, the role of this competition in disease onset is unclear. Here, we report that TYRP1 mRNA, in addition to encoding tyrosinase-related protein 1 (TYRP1), indirectly promotes cell proliferation by sequestering miR-16 on non-canonical miRNA response elements. Consequently, the sequestered miR-16 is no longer able to repress its mRNA targets, such as RAB17, which is involved in melanoma cell proliferation and tumour growth. Restoration of miR-16 tumour-suppressor function can be achieved in vitro by silencing TYRP1 or increasing miR-16 expression. Importantly, TYRP1-dependent miR-16 sequestration can also be overcome in vivo by using small oligonucleotides that mask miR-16-binding sites on TYRP1 mRNA. Together, our findings assign a pathogenic non-coding function to TYRP1 mRNA and highlight miRNA displacement as a promising targeted therapeutic approach for melanoma.

30Oct/17

Bottini S, Hamouda-Tekaya N, Mategot R, Zaragosi LE, Audebert S, Pisano S, Grandjean V, Mauduit C, Benahmed M, Barbry P, Repetto E, Trabucchi M

Nat Commun 2017 Oct;8(1):1189

Abstract

PMID: 29084942

There is a growing body of evidence about the presence and the activity of the miRISC in the nucleus of mammalian cells. Here, we show by quantitative proteomic analysis that Ago2 interacts with the nucleoplasmic protein Sfpq in an RNA-dependent fashion. By a combination of HITS-CLIP and transcriptomic analyses, we demonstrate that Sfpq directly controls the miRNA targeting of a subset of binding sites by local binding. Sfpq modulates miRNA targeting in both nucleoplasm and cytoplasm, indicating a nucleoplasmic commitment of Sfpq-target mRNAs that globally influences miRNA modes of action. Mechanistically, Sfpq binds to a sizeable set of long 3’UTRs forming aggregates to optimize miRNA positioning/recruitment at selected binding sites, including let-7a binding to Lin28A 3’UTR. Our results extend the miRNA-mediated post-transcriptional gene silencing into the nucleoplasm and indicate that an Sfpq-dependent strategy for controlling miRNA activity takes place in cells, contributing to the complexity of miRNA-dependent gene expression control.

17Oct/17

Alhaj Hussen K, Vu Manh TP, Guimiot F, Nelson E, Chabaane E, Delord M, Barbier M, Berthault C, Dulphy N, Alberdi AJ, Burlen-Defranoux O, Socié G, Bories JC, Larghero J, Vanneaux V, Verhoeyen E, Wirth T, Dalod M, Gluckman JC, Cumano A, Canque B

Immunity 2017 Oct;47(4):680-696.e8

Abstract

PMID: 29045900

The classical model of hematopoiesis established in the mouse postulates that lymphoid cells originate from a founder population of common lymphoid progenitors. Here, using a modeling approach in humanized mice, we showed that human lymphoid development stemmed from distinct populations of CD127(-) and CD127(+) early lymphoid progenitors (ELPs). Combining molecular analyses with in vitro and in vivo functional assays, we demonstrated that CD127(-) and CD127(+) ELPs emerged independently from lympho-mono-dendritic progenitors, responded differently to Notch1 signals, underwent divergent modes of lineage restriction, and displayed both common and specific differentiation potentials. Whereas CD127(-) ELPs comprised precursors of T cells, marginal zone B cells, and natural killer (NK) and innate lymphoid cells (ILCs), CD127(+) ELPs supported production of all NK cell, ILC, and B cell populations but lacked T potential. On the basis of these results, we propose a « two-family » model of human lymphoid development that differs from the prevailing model of hematopoiesis.

05Oct/17

Cluzeau T, McGraw KL, Irvine B, Masala E, Ades L, Basiorka AA, Maciejewski JP, Auberger P, Wei S, Fenaux P, Santini V, List A

Haematologica 2017 Oct;

Abstract

PMID: 28983059

Accumulating evidence implicates innate immune activation in the pathobiology of myelodysplastic syndromes. A key myeloid related inflammatory protein, S100A9, serves as a Toll-like receptor ligand regulating TNFα and IL-1β production. The role of MDS-related inflammatory proteins in endogenous Epo regulation and response to erythroid stimulating agents or lenalidomide has not been investigated. The HepG2 hepatoma cell line was used to investigate in vitro Epo elaboration. Serum collected from 311 MDS patients were investigated (125 prior to erythroid stimulating agents and 186 prior to lenalidomide). Serum concentrations of S100A9, S100A8, TNFα, IL1β and Epo were analyzed by ELISA. Using Epo-producing HepG2 cells, we show that S100A9, TNFα and IL-1β suppress transcription and cellular elaboration of Epo. Pre-incubation with lenalidomide significantly diminished suppression of Epo production by S100A9 or TNFα. Moreover, in myelodysplastic syndromes peripheral blood mononuclear cells, lenalidomide significantly reduced steady state S100A9 generation (p=0.01) and LPS-induced TNFα elaboration (p=0.002). ELISA analysis of serum from 316 non-del(5q) myelodysplastic syndromes patients demonstrated a significant inverse correlation between TNFα and Epo concentration (p=0.006), and between S100A9 and Epo (p=0.01). Moreover, baseline serum TNFα concentration was significantly higher in ESA responders (p=0.03), whereas lenalidomide responders had significantly lower TNFα and higher S100A9 serum concentrations (p=0.03). These findings suggest that S100A9 and its NF-kB transcriptional target, TNFα, directly suppress Epo elaboration in myelodysplastic syndromes. These cytokines may serve as rational biomarkers for response to lenalidomide and erythroid stimulating agent treatments. Therapeutic strategies that either neutralize or suppress S100A9 may improve erythropoiesis in myelodysplastic syndromes patients.

01Oct/17

Leduc M, Richard J, Costes S, Muller D, Varrault A, Compan V, Mathieu J, Tanti JF, Pagès G, Pouyssegur J, Bertrand G, Dalle S, Ravier MA

Diabetologia 2017 Oct;60(10):1999-2010

Abstract

PMID: 28721437

AIMS/HYPOTHESIS: Insufficient insulin secretion from pancreatic beta cells, which is associated with a decrease in beta cell mass, is a characteristic of type 2 diabetes. Extracellular signal-related kinase 1 and 2 (ERK1/2) inhibition in beta cells has been reported to affect insulin secretion, gene transcription and survival, although whether ERK1 and ERK2 play distinct roles is unknown. The aim of this study was to assess the individual roles of ERK1 and ERK2 in beta cells using ERK1 (also known as Mapk3)-knockout mice (Erk1 (-/-) mice) and pharmacological approaches.

METHODS: NAD(P)H, free cytosolic Ca(2+) concentration and insulin secretion were determined in islets. ERK1 and ERK2 subplasmalemmal translocation and activity was monitored using total internal reflection fluorescence microscopy. ERK1/2, mitogen and stress-activated kinase1 (MSK1) and cAMP-responsive element-binding protein (CREB) activation were evaluated by western blot and/or immunocytochemistry. The islet mass was determined from pancreatic sections.

RESULTS: Glucose induced rapid subplasmalemmal recruitment of ERK1 and ERK2. When both ERK1 and ERK2 were inhibited simultaneously, the rapid transient peak of the first phase of glucose-induced insulin secretion was reduced by 40% (p < 0.01), although ERK1 did not appear to be involved in this process. By contrast, ERK1 was required for glucose-induced full activation of several targets involved in beta cell survival; MSK1 and CREB were less active in Erk1 (-/-) mouse beta cells (p < 0.01) compared with Erk1 (+/+) mouse beta cells, and their phosphorylation could only be restored when ERK1 was re-expressed and not when ERK2 was overexpressed. Finally, the islet mass of Erk1 (-/-) mice was slightly increased in young animals (4-month-old mice) vs Erk1 (+/+) mice (section occupied by islets [mean ± SEM]: 0.74% ± 0.03% vs 0.62% ± 0.04%; p < 0.05), while older mice (10 months old) were less prone to age-associated pancreatic peri-insulitis (infiltrated islets [mean ± SEM]: 7.51% ± 1.34% vs 2.03% ± 0.51%; p < 0.001).

CONCLUSIONS/INTERPRETATION: ERK1 and ERK2 play specific roles in beta cells. ERK2 cannot always compensate for the lack of ERK1 but the absence of a clear-cut phenotype in Erk1 (-/-) mice shows that ERK1 is dispensable in normal conditions.

29Sep/17

Haider R, Massa F, Kaminski L, Clavel S, Djabari Z, Robert G, Laurent K, Michiels JF, Durand M, Ricci JE, Tanti JF, Bost F, Ambrosetti D

Oncotarget 2017 Sep;8(44):77309-77316

Abstract

PMID: 29100388

Predictive biomarkers for advanced prostate cancer (PCa) are still missing. The sirtuin 7 (SIRT7) has been linked to tumorogenesis but its role in prostate cancer is poorly documented. To determine if SIRT7 can be a biomarker for aggressive prostate cancer and plays a role in PCa aggressiveness. We analyzed the expression of SIRT7 by immunohistochemistry in 57 patients comparing healthy with adjacent cancer tissue. SIRT7 levels were significantly elevated in tumors and its expression was positively associated with the grade. We also demonstrated that the knock down of SIRT7 decreased the migration of DU145 and PC3 cells (two androgen-independent prostate cancer cell lines) whereas the overexpression of the native protein but not the mutated form increased the cell migration and the invasion of the poorly aggressive prostate cancer cell line LNCaP. Finally, we also showed that SIRT7 overexpression induced the resistance to docetaxel. Our results demonstrate that SIRT7 promotes prostate cancer cell aggressiveness and chemoresistance and suggest that SIRT7 is a good predictive biomarker of PCa aggressiveness.

26Sep/17

Dufies M, Giuliano S, Viotti J, Borchiellini D, Cooley LS, Ambrosetti D, Guyot M, Ndiaye PD, Parola J, Claren A, Schiappa R, Gal J, Frangeul A, Jacquel A, Cassuto O, Grépin R, Auberger P, Bikfalvi A, Milano G, Escudier B, Rioux-Leclercq N, Porta C, Negrier S, Chamorey E, Ferrero JM, Pagès G

Br. J. Cancer 2017 Sep;117(7):947-953

Abstract

PMID: 28850564

BACKGROUND: Sunitinib is one of the first-line standard treatments for metastatic clear cell renal cell carcinoma (ccRCC) with a median time to progression shorter than 1 year. The objective is to discover predictive markers of response to adapt the treatment at diagnosis.

METHODS: Prospective phase 2 multi-centre trials were conducted in ccRCC patients initiating sunitinib (54 patients) or bevacizumab (45 patients) in the first-line metastatic setting (SUVEGIL and TORAVA trials). The plasmatic level of CXCL7 at baseline was correlated with progression-free survival (PFS).

RESULTS: The cut-off value of CXCL7 for PFS was 250 ng ml(-1). Patients with CXCL7 plasmatic levels above the cut-off at baseline (250 ng ml(-1)) had a significantly longer PFS (hazard ratio 0.323 (95% confidence interval 0.147-0.707), P=0.001). These results were confirmed in a retrospective validation cohort. The levels of CXCL7 did not influence PFS of the bevacizumab-treated patients.

CONCLUSIONS: CXCL7 may be considered as a predictive marker of sunitinib efficacy for ccRCC patients.

19Sep/17

Villa E, Proïcs E, Rubio-Patiño C, Obba S, Zunino B, Bossowski JP, Rozier RM, Chiche J, Mondragón L, Riley JS, Marchetti S, Verhoeyen E, Tait SWG, Ricci JE

Cell Rep 2017 Sep;20(12):2846-2859

Abstract

PMID: 28930681

Mitophagy is an evolutionarily conserved process that selectively targets impaired mitochondria for degradation. Defects in mitophagy are often associated with diverse pathologies, including cancer. Because the main known regulators of mitophagy are frequently inactivated in cancer cells, the mechanisms that regulate mitophagy in cancer cells are not fully understood. Here, we identified an E3 ubiquitin ligase (ARIH1/HHARI) that triggers mitophagy in cancer cells in a PINK1-dependent manner. We found that ARIH1/HHARI polyubiquitinates damaged mitochondria, leading to their removal via autophagy. Importantly, ARIH1 is widely expressed in cancer cells, notably in breast and lung adenocarcinomas; ARIH1 expression protects against chemotherapy-induced death. These data challenge the view that the main regulators of mitophagy are tumor suppressors, arguing instead that ARIH1-mediated mitophagy promotes therapeutic resistance.

05Sep/17

Danin PE, Anty R, Patouraux S, Raucoules-Aimé M, Gugenheim J, Tran A, Gual P, Iannelli A

Obes Surg 2017 Sep;

Abstract

PMID: 28875438

BACKGROUND: Overweight and obesity dramatically increased in the last years. Hepatic complication of obesity, integrated in the term of non-alcoholic fatty liver disease (NAFLD), is a spectrum of abnormality ranging from steatosis to non-alcoholic steatohepatitis (NASH), potentially leading to cirrhosis. Liver biopsy remains the gold standard to evaluate the stage of NAFLD; however, the procedure is invasive. The indocyanine green (ICG) clearance test is performed since years to assess hepatic function before partial hepatectomy, or after liver transplantation. This study was designed to detect liver complications with the ICG clearance test in a population of obese patients scheduled for bariatric surgery.

METHODS: In a prospective cohort study, morbidly obese individuals receiving bariatric surgery with scheduled hepatic biopsies were investigated. Liver function was determined by the ICG test preoperatively, and blood samples were collected. Liver biopsy specimens were obtained for each patient and classified according to the NAFLD activity score (NAS) by a single pathologist that was blinded to the results of the ICG test.

RESULTS: Twenty-six patients were included (7 male and 19 female). The mean age of participants was 45.8 years; the mean body mass index was 41.4 kg/m(2). According to the NAS, 6 (23.1%) patients revealed manifest NASH, and 5 patients were considered borderline (19.2%). A closed correlation was observed between the ICG clearance test and hepatic steatosis (r = 0.43, p = 0.03), NAS (r = 0.44, p = 0.025), and fibrosis (r = 0.49, p = 0.01).

CONCLUSIONS: In obese patients, non-invasive evaluation of liver function with the indocyanine green clearance test correlated with histological features of NAFLD. This may detect non-invasively hepatopathy in obese population and could motive biopsy.

01Sep/17

Giampazolias E, Zunino B, Dhayade S, Bock F, Cloix C, Cao K, Roca A, Lopez J, Ichim G, Proïcs E, Rubio-Patiño C, Fort L, Yatim N, Woodham E, Orozco S, Taraborrelli L, Peltzer N, Lecis D, Machesky L, Walczak H, Albert ML, Milling S, Oberst A, Ricci JE, Ryan KM, Blyth K, Tait SWG

Nat. Cell Biol. 2017 Sep;19(9):1116-1129

Abstract

PMID: 28846096

Apoptosis represents a key anti-cancer therapeutic effector mechanism. During apoptosis, mitochondrial outer membrane permeabilization (MOMP) typically kills cells even in the absence of caspase activity. Caspase activity can also have a variety of unwanted consequences that include DNA damage. We therefore investigated whether MOMP-induced caspase-independent cell death (CICD) might be a better way to kill cancer cells. We find that cells undergoing CICD display potent pro-inflammatory effects relative to apoptosis. Underlying this, MOMP was found to stimulate NF-κB activity through the downregulation of inhibitor of apoptosis proteins. Strikingly, engagement of CICD displays potent anti-tumorigenic effects, often promoting complete tumour regression in a manner dependent on intact immunity. Our data demonstrate that by activating NF-κB, MOMP can exert additional signalling functions besides triggering cell death. Moreover, they support a rationale for engaging caspase-independent cell death in cell-killing anti-cancer therapies.

24Août/17

Regazzetti C, Sormani L, Debayle D, Bernerd F, Tulic MK, De Donatis GM, Chignon-Sicard B, Rocchi S, Passeron T

J. Invest. Dermatol. 2017 Aug;

Abstract

PMID: 28842328

The shorter wavelengths of the visible light spectrum have been recently reported to induce a long-lasting hyperpigmentation but only in melano-competent individuals. Here, we provide evidence showing that OPN3 is the key sensor in melanocytes responsible for hyperpigmentation induced by the shorter wavelengths of visible light. The melanogenesis induced through OPN3 is calcium dependent and further activates CAMKII followed by CREB, extracellular signal-regulated kinase, and p38, leading to the phosphorylation of MITF and ultimately to the increase of the melanogenesis enzymes: tyrosinase and dopachrome tautomerase. Furthermore, blue light induces the formation of a protein complex that we showed to be formed by tyrosinase and dopachrome tautomerase. This multimeric tyrosinase/tyrosinase-related protein complex is mainly formed in dark-skinned melanocytes and induces a sustained tyrosinase activity, thus explaining the long-lasting hyperpigmentation that is observed only in skin type III and higher after blue light irradiation. OPN3 thus functions as the sensor for visible light pigmentation. OPN3 and the multimeric tyrosinase/tyrosinase-related protein complex induced after its activation appear as new potential targets for regulating melanogenesis but also to protect dark skins against blue light in physiological conditions and in pigmentary disorders.

21Août/17

Leclerc J, Ballotti R, Bertolotto C

Oncogene 2017 Aug;

Abstract

PMID: 28825724

Cutaneous melanoma is a deadly skin cancer that originates from melanocytes. The development of cutaneous melanoma involves a complex interaction between environmental factors, mainly ultraviolet radiation from sunlight, and genetic alterations. Melanoma can also occur from a pre-existing nevus, a benign lesion formed from melanocytes harboring oncogenic mutations that trigger proliferative arrest and senescence entry. Senescence is a potent barrier against tumor progression. As such, the acquisition of mutations that suppress senescence and promote cell division is mandatory for cancer development. This topic appears central to melanoma development because, in humans, several somatic and germline mutations are related to the control of cellular senescence and proliferative activity. Consequently, primary melanoma can be viewed as a paradigm of senescence evasion. In support of this notion, a sumoylation-defective germline mutation in microphthalmia-associated transcription factor (MITF), a master regulator of melanocyte homeostasis, is associated with the development of melanoma. Interestingly, this MITF variant has also been recently reported to negatively impact the program of senescence. This article reviews the genetic alterations that have been shown to be involved in melanoma and that alter the process of senescence to favor melanoma development. Then, the transcription factor MITF and its sumoylation-defective mutant are described. How sumoylation misregulation can change MITF activity and impact the process of senescence is discussed. Finally, the contribution of such information to the development of anti-malignant melanoma strategies is evaluated.Oncogene advance online publication, 21 August 2017; doi:10.1038/onc.2017.292.

15Août/17

Priya A, Sugatha J, Parveen S, Lacas-Gervais S, Raj P, Gilleron J, Datta S

J. Cell. Sci. 2017 Aug;130(16):2707-2721

Abstract

PMID: 28705836

The endosomal protein-sorting machineries play vital roles in diverse physiologically important cellular processes. Much of the core membrane-sorting apparatus is conserved in evolution, such as retromer, which is involved in the recycling of a diverse set of cargoes via the retrograde trafficking route. Here, in an RNAi-based loss-of-function study, we identified that suppression of SNX12 leads to a severe blockage in CIM6PR (also known as IGF2R) transport and alters the morphology of the endocytic compartments. We demonstrate that SNX12 is involved in the early phase of CIM6PR transport, and mediates receptor recycling upstream of the other well-established SNX components of retromer. Ultra-structural analysis revealed that SNX12 resides on tubulo-vesicular structures, despite it lacking a BAR domain. Furthermore, we illustrate that SNX12 plays a key role in intraluminal vesicle formation and in the maturation of a subpopulation of early endosomes into late endosomes, thereby regulating selective endocytic transport of cargo for degradation. This study therefore provides evidence for the existence of early endosomal subpopulations that have differential roles in the sorting of the cargoes along endocytic degradative pathways.

01Août/17

Bonet C, Luciani F, Ottavi JF, Leclerc J, Jouenne FM, Boncompagni M, Bille K, Hofman V, Bossis G, Marco de Donatis G, Strub T, Cheli Y, Ohanna M, Luciano F, Marchetti S, Rocchi S, Birling MC, Avril MF, Poulalhon N, Luc T, Bertolotto C

J. Natl. Cancer Inst. 2017 08;109(8)

Abstract

PMID: 28376192

Background: MITF encodes an oncogenic lineage-specific transcription factor in which a germline mutation ( MITFE318K ) was identified in human patients predisposed to both nevus formation and, among other tumor types, melanoma. The molecular mechanisms underlying the oncogenic activity of MITF E318K remained uncharacterized.

Methods: Here, we compared the SUMOylation status of endogenous MITF by proximity ligation assay in melanocytes isolated from wild-type (n = 3) or E318K (n = 4) MITF donors. We also used a newly generated Mitf E318K knock-in (KI) mouse model to assess the role of Mitf E318K (n = 7 to 13 mice per group) in tumor development in vivo and performed transcriptomic analysis of the tumors to identify the molecular mechanisms. Finally, using immortalized or normal melanocytes (wild-type or E318K MITF, n = 2 per group), we assessed the role of MITF E318K on the induction of senescence mediated by BRAF V600E . All statistical tests were two-sided.

Results: We demonstrated a decrease in endogenous MITF SUMOylation in melanocytes from MITF E318K patients (mean of cells with hypoSUMOylated MITF, MITF E318K vs MITF WT , 94% vs 44%, difference = 50%, 95% CI = 21.8% to 67.2%, P  = .004). The Mitf E318K mice were slightly hypopigmented (mean melanin content Mitf WT vs Mitf E318K/+ , 0.54 arbitrary units [AU] vs 0.36 AU, difference = -0.18, 95% CI = -0.36 to -0.007, P  = .04). We provided genetic evidence that Mitf E318K enhances BRaf V600E -induced nevus formation in vivo (mean nevus number for Mitf E318K , BRaf V600E vs Mitf WT , BRaf V600E , 68 vs 44, difference = 24, 95% CI = 9.1 to 38.9, P  = .006). Importantly, although Mitf E318K was not sufficient to cooperate with BRaf V600E alone in promoting metastatic melanoma, it accelerated tumor formation on a BRaf V600E , Pten-deficient background (median survival, Mitf E318K/+  = 42 days, 95% CI = 31 to 46 vs Mitf WT  = 51 days, 95% CI = 50 to 55, P  < .001). Transcriptome analysis suggested a decrease in senescence in tumors from Mitf E318K mice. We confirmed this hypothesis by in vitro experiments, demonstrating that Mitf E318K impaired the ability of human melanocytes to undergo BRAF V600E -induced senescence.

Conclusions: We characterized the functions of melanoma-associated MITF E318K mutations. Our results demonstrate that MITF E318K reduces the program of senescence to potentially favor melanoma progression in vivo.

01Août/17

Pastor F, Dumas K, Barthélémy MA, Regazzetti C, Druelle N, Peraldi P, Cormont M, Tanti JF, Giorgetti-Peraldi S

Sci Rep 2017 Aug;7(1):7023

Abstract

PMID: 28765650

In response to endotoxemia, the organism triggers an inflammatory response, and the visceral adipose tissue represents a major source of proinflammatory cytokines. The regulation of inflammation response in the adipose tissue is thus of crucial importance. We demonstrated that Regulated in development and DNA damage response-1 (REDD1) is involved in inflammation. REDD1 expression was increased in response to lipopolysaccharide (LPS) in bone marrow derived macrophages (BMDM) and in epidydimal adipose tissue. Loss of REDD1 protected the development of inflammation, since the expression of proinflammatory cytokines (TNFα, IL-6, IL-1β) was decreased in adipose tissue of REDD1(-/-) mice injected with LPS compared to wild-type mice. This decrease was associated with an inhibition of the activation of p38MAPK, JNK, NF-κB and NLRP3 inflammasome leading to a reduction of IL-1β secretion in response to LPS and ATP in REDD1(-/-) BMDM. Although REDD1 is an inhibitor of mTORC1, loss of REDD1 decreased inflammation independently of mTORC1 activation but more likely through oxidative stress regulation. Absence of REDD1 decreases ROS associated with a dysregulation of Nox-1 and GPx3 expression. Absence of REDD1 in macrophages decreases the development of insulin resistance in adipocyte-macrophage coculture. Altogether, REDD1 appears to be a key player in the control of inflammation.

01Août/17

Patouraux S, Rousseau D, Bonnafous S, Lebeaupin C, Luci C, Canivet CM, Schneck AS, Bertola A, Saint-Paul MC, Iannelli A, Gugenheim J, Anty R, Tran A, Bailly-Maitre B, Gual P

J. Hepatol. 2017 Aug;67(2):328-338

Abstract

PMID: 28323124

BACKGROUND & AIMS: Cluster of differentiation (CD)44 regulates adipose tissue inflammation in obesity and hepatic leukocyte recruitment in a lithogenic context. However, its role in hepatic inflammation in a mouse model of steatohepatitis and its relevance in humans have not yet been investigated. We aimed to evaluated the contribution of CD44 to non-alcoholic steatohepatitis (NASH) development and liver injury in mouse models and in patients at various stages of non-alcoholic fatty liver disease (NAFLD) progression.

METHODS: The role of CD44 was evaluated in CD44(-/-) mice and after injections of an αCD44 antibody in wild-type mice challenged with a methionine- and choline-deficient diet (MCDD). In obese patients, hepatic CD44 (n=30 and 5 NASH patients with a second liver biopsy after bariatric surgery) and serum sCD44 (n=64) were evaluated.

RESULTS: Liver inflammation (including inflammatory foci number, macrophage and neutrophil infiltration and CCL2/CCR2 levels), liver injury and fibrosis strongly decreased in CD44(-/-) mice compared to wild-type mice on MCDD. CD44 deficiency enhanced the M2 polarization and strongly decreased the activation of macrophages by lipopolysaccharide (LPS), hepatocyte damage-associated molecular patterns (DAMPs) and saturated fatty acids. Neutralization of CD44 in mice with steatohepatitis strongly decreased the macrophage infiltration and chemokine ligand (CCL)2 expression with a partial correction of liver inflammation and injury. In obese patients, hepatic CD44 was strongly upregulated in NASH patients (p=0.0008) and correlated with NAFLD activity score (NAS) (p=0.001), ballooning (p=0.003), alanine transaminase (p=0.005) and hepatic CCL2 (p<0.001) and macrophage marker CD68 (p<0.001) expression. Correction of NASH was associated with a strong decrease in liver CD44(+) cells. Finally, the soluble form of CD44 increased with severe steatosis (p=0.0005) and NASH (p=0.007).

CONCLUSION: Human and experimental data suggest that CD44 is a marker and key player of hepatic inflammation and its targeting partially corrects NASH.

LAY SUMMARY: Human and experimental data suggest that CD44, a cellular protein mainly expressed in immune cells, is a marker and key player of non-alcoholic steatohepatitis (NASH). Indeed, CD44 enhances the non-alcoholic fatty liver (NAFL) (hepatic steatosis) to NASH progression by regulating hepatic macrophage polarization (pro-inflammatory phenotype) and infiltration (macrophage motility and the MCP1/CCL2/CCR2 system). Targeting CD44 partially corrects NASH, making it a potential therapeutic strategy.

01Août/17

Mazure NM

Biochim. Biophys. Acta 2017 08;1858(8):665-673

Abstract

PMID: 28283400

The voltage-dependent anion channel (VDAC) is a pore located at the outer membrane of the mitochondrion. It allows the entry and exit of numerous ions and metabolites between the cytosol and the mitochondrion. Flux through the pore occurs in an active way: first, it depends on the open or closed state and second, on the negative or positive charges of the different ion species passing through the pore. The flux of essential metabolites, such as ATP, determines the functioning of the mitochondria to a noxious stimulus. Moreover, VDAC acts as a platform for many proteins and in so doing supports glycolysis and prevents apoptosis by interacting with hexokinase, or members of the Bcl-2 family, respectively. VDAC is thus involved in the choice the cells make to survive or die, which is particularly relevant to cancer cells. For these reasons, VDAC has become a potential therapeutic target to fight cancer but also other diseases in which mitochondrial metabolism is modified. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux.

18Juil/17

Vidal V, Robert G, Goursaud L, Durand L, Ginet C, Karsenti JM, Luciano F, Gastaud L, Garnier G, Braun T, Hirsch P, Raffoux E, Nloga AM, Padua RA, Dombret H, Rohrlich P, Ades L, Chomienne C, Auberger P, Fenaux P, Cluzeau T

Oncotarget 2017 Jul;8(29):47103-47109

Abstract

PMID: 28514758

Azacitidine (AZA), the reference treatment for most higher-risk myelodysplastic (MDS) patients can also improve overall survival (OS) in elderly acute myeloid leukemia (AML) patients ineligible for intensive chemotherapy, but reliable biological markers predicting response and OS in patients treated with AZA are lacking. In a preliminary study, we found that an increase of the percentage of BCL2L10, an anti-apoptotic member of the bcl-2 family, was correlated with AZA resistance. In this study, we assessed prospectively by flow cytometry the prognostic value of BCL2L10 positive bone marrow mononuclear cells in 70 patients (42 MDS and 28 AML), prior to AZA treatment.In patients with baseline marrow blasts below 30%, the baseline percentage of bone marrow BCL2L10 positive cells inversely correlated with response to AZA and OS independently of the International Prognostic Scoring System (IPSS) and IPSS-revised (IPSS-R). Specifically, OS was significantly lower in patients with more than 10% BCL2L10 positive cells (median 8.3 vs 22.9 months in patients with less than 10% positivity, p = 0,001). In summary, marrow BCL2L10 positive cells may be a biomarker for azacitidine response and OS, with a potential impact in clinical practice.

15Juil/17

Lagadec P, Balaguer T, Boukhechba F, Michel G, Bouvet-Gerbettaz S, Bouler JM, Scimeca JC, Rochet N

Acta Biomater 2017 Jul;57:462-471

Abstract

PMID: 28528118

Interaction of host blood with biomaterials is the first event occurring after implantation in a bone defect. This study aimed at investigating the cellular and molecular consequences arising at the interface between whole blood and biphasic calcium phosphate (BCP) particles. We observed that, due to calcium capture, BCP inhibited blood coagulation, and that this inhibition was reversed by calcium supplementation. Therefore, we studied the impact of calcium supplementation on BCP effects on blood cells. Comparative analysis of BCP and calcium supplemented-BCP (BCP/Ca) effects on blood cells showed that BCP as well as BCP/Ca induced monocyte proliferation, as well as a weak but significant hemolysis. Our data showed for the first time that calcium supplementation of BCP microparticles had anti-inflammatory properties compared to BCP alone that induced an inflammatory response in blood cells. Our results strongly suggest that the anti-inflammatory property of calcium supplemented-BCP results from its down-modulating effect on P2X7R gene expression and its capacity to inhibit ATP/P2X7R interactions, decreasing the NLRP3 inflammasome activation. Considering that monocytes have a vast regenerative potential, and since the excessive inflammation often observed after bone substitutes implantation limits their performance, our results might have great implications in terms of understanding the mechanisms leading to an efficient bone reconstruction.

STATEMENT OF SIGNIFICANCE: Although scaffolds and biomaterials unavoidably come into direct contact with blood during bone defect filling, whole blood-biomaterials interactions have been poorly explored. By studying in 3D the interactions between biphasic calcium phosphate (BCP) in microparticulate form and blood, we showed for the first time that calcium supplementation of BCP microparticles (BCP/Ca) has anti-inflammatory properties compared to BCP-induced inflammation in whole blood cells and provided information related to the molecular mechanisms involved. The present study also showed that BCP, as well as BCP/Ca particles stimulate monocyte proliferation. As monocytes represent a powerful target for regenerative therapies and as an excessive inflammation limits the performance of biomaterials in bone tissue engineering, our results might have great implications to improve bone reconstruction.

11Juil/17

Loubiere C, Clavel S, Gilleron J, Harisseh R, Fauconnier J, Ben-Sahra I, Kaminski L, Laurent K, Herkenne S, Lacas-Gervais S, Ambrosetti D, Alcor D, Rocchi S, Cormont M, Michiels JF, Mari B, Mazure NM, Scorrano L, Lacampagne A, Gharib A, Tanti JF, Bost F

Sci Rep 2017 Jul;7(1):5040

Abstract

PMID: 28698627

Mitochondrial integrity is critical for the regulation of cellular energy and apoptosis. Metformin is an energy disruptor targeting complex I of the respiratory chain. We demonstrate that metformin induces endoplasmic reticulum (ER) stress, calcium release from the ER and subsequent uptake of calcium into the mitochondria, thus leading to mitochondrial swelling. Metformin triggers the disorganization of the cristae and inner mitochondrial membrane in several cancer cells and tumors. Mechanistically, these alterations were found to be due to calcium entry into the mitochondria, because the swelling induced by metformin was reversed by the inhibition of mitochondrial calcium uniporter (MCU). We also demonstrated that metformin inhibits the opening of mPTP and induces mitochondrial biogenesis. Altogether, the inhibition of mPTP and the increase in mitochondrial biogenesis may account for the poor pro-apoptotic effect of metformin in cancer cells.

23Juin/17

Stefani C, Gonzalez-Rodriguez D, Senju Y, Doye A, Efimova N, Janel S, Lipuma J, Tsai MC, Hamaoui D, Maddugoda MP, Cochet-Escartin O, Prévost C, Lafont F, Svitkina T, Lappalainen P, Bassereau P, Lemichez E

Nat Commun 2017 Jun;8:15839

Abstract

PMID: 28643776

Transendothelial cell macroaperture (TEM) tunnels control endothelium barrier function and are triggered by several toxins from pathogenic bacteria that provoke vascular leakage. Cellular dewetting theory predicted that a line tension of uncharacterized origin works at TEM boundaries to limit their widening. Here, by conducting high-resolution microscopy approaches we unveil the presence of an actomyosin cable encircling TEMs. We develop a theoretical cellular dewetting framework to interpret TEM physical parameters that are quantitatively determined by laser ablation experiments. This establishes the critical role of ezrin and non-muscle myosin II (NMII) in the progressive implementation of line tension. Mechanistically, fluorescence-recovery-after-photobleaching experiments point for the upstream role of ezrin in stabilizing actin filaments at the edges of TEMs, thereby favouring their crosslinking by NMIIa. Collectively, our findings ascribe to ezrin and NMIIa a critical function of enhancing line tension at the cell boundary surrounding the TEMs by promoting the formation of an actomyosin ring.

15Juin/17

Solly F, Koering C, Mohamed AM, Maucort-Boulch D, Robert G, Auberger P, Flandrin-Gresta P, Adès L, Fenaux P, Kosmider O, Tavernier-Tardy E, Cornillon J, Guyotat D, Campos L, Mortreux F, Wattel E

Clin. Cancer Res. 2017 Jun;23(12):3025-3034

Abstract

PMID: 27881579

Purpose: Azacitidine inhibits DNA methyltransferases, including DNMT1, and is currently the standard of care for patients with higher-risk myelodysplastic syndrome (HRMDS) or low blast count acute myeloid leukemia (AML).Experimental Design: The expression of 754 miRNAs was compared in azacitidine-resistant and azacitidine-sensitive myelodysplastic syndrome cells. We investigated the role of differentially expressed miRNAs on DNMT1 expression and azacitidine resistance in vitro We next evaluated anti-DNMT1 miRNA expression in pretreatment bone marrow samples derived from 75 patients treated with azacitidine for HRMDS or AML.Results: Seven miRNAs, including 5 that in silico targeted the DNMT1 3′ UTR, were repressed in azacitidine-resistant cells in which DNMT1 protein levels were significantly higher. Ectopic anti-DNMT1 miRNA expression decreased DNMT1 expression and increased azacitidine sensitivity, whereas specific inhibition of endogenous anti-DNMT1 miRNAs increased DNMT1 expression and triggered azacitidine resistance. In patients treated with azacitidine, decreased expression of anti-DNMT1 miRNAs was associated with poor outcome. miR-126* had the strongest prognostic impact. Patients with miR-126*(low) myelodysplastic syndrome had significantly lower response rates (P = 0.04) and higher relapse rates (P = 0.03), as well as shorter progression-free (PFS; P = 0.004) and overall survival (OS; P = 0.004). Multivariate analysis showed that age, miR-126* expression, and revised International Prognostic Scoring System risk independently predicted PFS and OS. In 15 patient samples collected over time, decreased miRNA expression levels were associated with secondary resistance.Conclusions: A decreased expression of anti-DNMT1 miRNAs might account for azacitidine resistance in HRMDS and AML, and measuring miRNA expression before and during treatment might help predict primary or secondary azacitidine resistance. Clin Cancer Res; 23(12); 3025-34. ©2016 AACR.

12Juin/17

Bottini S, Pratella D, Grandjean V, Repetto E, Trabucchi M

Brief. Bioinformatics 2017 Jun;

Abstract

PMID: 28605404

Cross-Linking Immunoprecipitation associated to high-throughput sequencing (CLIP-seq) is a technique used to identify RNA directly bound to RNA-binding proteins across the entire transcriptome in cell or tissue samples. Recent technological and computational advances permit the analysis of many CLIP-seq samples simultaneously, allowing us to reveal the comprehensive network of RNA-protein interaction and to integrate it to other genome-wide analyses. Therefore, the design and quality management of the CLIP-seq analyses are of critical importance to extract clean and biological meaningful information from CLIP-seq experiments. The application of CLIP-seq technique to Argonaute 2 (Ago2) protein, the main component of the microRNA (miRNA)-induced silencing complex, reveals the direct binding sites of miRNAs, thus providing insightful information about the role played by miRNA(s). In this review, we summarize and discuss the most recent computational methods for CLIP-seq analysis, and discuss their impact on Ago2/miRNA-binding site identification and prediction with a regard toward human pathologies.

06Juin/17

Westerterp M, Gautier EL, Ganda A, Molusky MM, Wang W, Fotakis P, Wang N, Randolph GJ, D’Agati VD, Yvan-Charvet L, Tall AR

Cell Metab. 2017 Jun;25(6):1294-1304.e6

Abstract

PMID: 28479366

Autoimmune diseases such as systemic lupus erythematosus (SLE) are associated with increased cardiovascular disease and reduced plasma high-density lipoprotein (HDL) levels. HDL mediates cholesterol efflux from immune cells via the ATP binding cassette transporters A1 and G1 (ABCA1/G1). The significance of impaired cholesterol efflux pathways in autoimmunity is unknown. We observed that Abca1/g1-deficient mice develop enlarged lymph nodes (LNs) and glomerulonephritis suggestive of SLE. This lupus-like phenotype was recapitulated in mice with knockouts of Abca1/g1 in dendritic cells (DCs), but not in macrophages or T cells. DC-Abca1/g1 deficiency increased LN and splenic CD11b(+) DCs, which displayed cholesterol accumulation and inflammasome activation, increased cell surface levels of the granulocyte macrophage-colony stimulating factor receptor, and enhanced inflammatory cytokine secretion. Consequently, DC-Abca1/g1 deficiency enhanced T cell activation and Th1 and Th17 cell polarization. Nlrp3 inflammasome deficiency diminished the enlarged LNs and enhanced Th1 cell polarization. These findings identify an essential role of DC cholesterol efflux pathways in maintaining immune tolerance.