Tim-3 has been linked to several inflammatory diseases by regulation on both adaptive and innate immunities. Here, we assessed the augmented expression of Tim-3 in brain tissue of ischemia-reperfusion mice and PBMCs of ischemic stroke (IS) patients. The augmented expression of Tim-3 significantly correlated with abnormal lipid levels. In vitro studies showed that plasma from ischemic stroke patients induced Tim-3 expression in THP- 1 cells. More importantly, our results revealed a significant correlation of Tim-3 expression on CD4 + T cells with systemic IL-17 in patients with ischemic stroke. Consistently, we also found a positive correlation of Tim-3 expression on CD14 + monocytes and serum TNF-a in IS patients. Collectively, augmented expression of Tim-3 may play an important role in the pathogenesis of ischemic stroke by regulation of proinflammatory cytokines. Further studies will give us new insights on the pathogenesis of ischemic stroke and potentially provide a new target at the medical therapy.

Dietary vitamin E, highly expressed in palm oil, exists as either tocopherols or tocotrienols. Evidence indicates that vitamin Es maybe potent cancer preventive agents. In this study, the y- and O- isoforms of vitamin E were found to he the most effective at cancer cell growth inhibition, with the tocotrienols being more effective than the tocopherols in androgen-independent PC-3 prostate cancer cells. To assure that these compounds were selective toward cancer cells, the growth arrest of PrEC normal prostate cells was compared to PC-3 cells. At concentrations of -30 iM dietary, y-vitamin Es showed no signficant growth arrest on PrEC cell growth, hut selectively inhibited growth in the PC-3 cancer cells. Moreover y-Tocotrienol demonstrated a greater potential to inhibit growth in cancer cells at these lower concentrations than did y-Tocopherol. Two independent pathways important in carcinogenesis were tested: PPAR y and NFicB. The PPAR y was up regulated by both dietary y-vitamin Es by the modulation of the endogenous ligand 15-S-HETE, while NFicB was only regulated by y-Tocotrienol. The modulation of NFicB was confirmed by the down regulation of the pro-Apoptotic proteins clAP, xIAP, and BcL-2 which potentiate apoptosis and are down stream effectors of NFicB.

No description available.

Les cellules progénitrices endothéliales formant des colonies (EFCFs) sont issues decellules CD34+ de la moelle osseuse humaine. Peu de données concernent l’expression dufacteur tissulaire (FT) lors de cette différenciation endothéliale. Outre son rôle dansl’initiation de la génération de thrombine, le FT est impliqué dans l’angiogenèse.Nous montrons que les cellules CD34+ expriment le FT mais non ses isoformes. LesECFCs expriment peu de FT à l’état basal. En revanche, leur stimulation par le TNF-α induitune augmentation de l’expression de FT, et la génération de microparticules pro-coagulantes.Nous avons analysé les modifications fonctionnelles induites par cette stimulation. Nosrésultats montrent que l’expression de FT par les ECFCs est responsable d’une activité procoagulante majeure, alors que les propriétés angiogéniques ne semblent pas affectées.L’expression du tissue factor pathway inhibitor (TFPI) a été évaluée, ainsi que la capacité desmicroparticules issues de ECFCs à générer des métalloprotéinases (MMP2-, MMP-9).Une évaluation de la stabilité chromosomique des cb-ECFCs durant leur expansion aété réalisée, mettant en évidence des anomalies de nombre, mais pas d’anomalies destructures. Les conséquences de ces résultats en termes de thérapie cellulaire appliquées auxpathologies cardio-vasculaires sont discutées. Enfin, nous évoquons la possibilité deconsidérer l’expression de FT comme un marqueur de différenciation cellulaire. / Endothelial colony-forming cells (ECFCs) can be obtained from human bone marrowCD34+ cells. In spite of the essential role of the tissue factor (TF) in coagulation triggeringand angiogenesis, its expression during endothelial differentiation is not established. We showthat CD34+ cells express TF, but not TF splicing forms. ECFCs express a small amount of TFat baseline level. In contrast, ECFCs express TF high levels of TF on response to TNF-α andcan generated highly pro-coagulant microparticles. We have examined the functionalproperties induced by TNF-α stimulation. TF expression confers to ECFCs a strong thrombingeneration capacity without influencing their non-coagulant properties. We have examinedthe co-expression of the tissue factor pathway inhibitor (TFPI) and the ability of ECFCs togenerate microparticles producing metalloproteins (MMP-2, MMP-9).We have performed an evaluation of cb-ECFCs chromosomal stability during theirexpansion. We found quantitative but no structural chromosomal abnormalities. Theconsequences of our observations in the use of cell therapy in cardiovascular diseases arediscussed. We conclude that TF expression may be considered as cell differentiation marker

This dissertation focuses on rationalised DNA design as a tool for the discovery and development of new therapeutic entities, as well as understanding the biological function of DNA beyond the storage of genetic information. The study is comprised of two main areas of study: (i) the use of DNA as a coding unit to illustrate the relationship between code-diversity and dynamics of self-assembly; and (ii) the use of DNA as an active unit that interacts and regulates a target protein. In the study of DNA as a coding unit in code-diversity and dynamics of self-assembly, we developed the DNA-Based Diversity Modelling and Analysis (DDMA) method. Using Polymerase Chain Reaction (PCR) and Real Time Polymerase Chain Reaction (RT-PCR), we studied the diversity and evolution of synthetic oligonucleotide populations. The manipulation of critical conditions, with monitoring and interpretation of their effects, lead to understanding how PCR amplification unfolding could reshape a population. This new take on an old technology has great value for the study of: (a) code-diversity, convenient in a DNA-based selection method, so semi-quantitation can evaluate a selection development and the population\'s behaviour can indicate the quality; (b) self-assembly dynamics, for the simulation of a real evolution, emulating a society where selective pressures direct the population's adaptation; and (c) development of high-entropy DNA structures, in order to understand how similar unspecific DNA structures are formed in certain pathologies, such as in auto-immune diseases. To explore DNA as an active unit in Tumour Necrosis Factor α (TNF-α) interaction and activity modulation, we investigate DNA's influence on its spatial conformation by physical environment regulation. Active TNF-α is a trimer and the protein-protein interactions between its monomers are a promising target for drug development. It has been hypothesised that TNF-α forms a very intricate network after its activation between its subunits and receptors, but the mechanism is still not completely clear. During our research, we estimate the non-specific DNA binding to TNF-α in the low micro-molar range. Cell toxicity assays confirm this interaction, where DNA consistently enhances TNF-α's cytotoxic effect. Further binding and structural studies lead to the same conclusion that DNA binds and interferes with TNF-α structure. From this protein-DNA interaction study, a new set of tools to regulate TNF-α's biological activity can be developed and its own biology can be unveiled.

Fragestellung: Wir gingen der Frage nach, inwieweit genetische Variationen im Gen für den Tumor Nekrose Faktor-alpha einen Einfluß auf die Krankheitsprogression oder die Entstehung bzw. Ausprägung HIV-assoziierter Erkrankungen haben. Methoden: Die Promotorregion sowie die kodierenden Sequenzen des TNF-alpha-Gens wurden mittels SSCP-Analyse auf genetische Variationen untersucht. Anschließend erfolgte die Charakterisierung der häufigsten bekannten Promotorpolymorphismen mittels Restriktionsfragment-Längenpolymorphismus-Analyse (RFLP). Die Bestätigung der Polymorphismen der RFLP-Analyse erfolgte an ausgewählten Proben durch DNA-Fluoreszenzsequenzierung. In sämtlichen Fällen handelte es sich um singuläre Basentransitionen von Guanin zu Adenin. Ergebnisse: Unter Einbeziehung verschiedener Progressionsparameter wie der CD4-Zellzahl, des Zeitraumes vom ARC-Stadium zum AIDS-Stadium und AIDS-assoziierter Krankheiten wie dem Wasting Syndrom und der HIV-Enzephalopathie, erfolgte anschließend die statistische Analyse in Korrelation mit den ermittelten Genotypen. Es zeigte sich bei keiner der statistischen Analysen eine signifikante Assoziation mit einem bestimmten TNF-alpha-Genotyp. Schlußfolgerung: Es ist kritisch anzumerken, daß für einige Subanalysen die Größe der untersuchten Patientengruppe zu gering war, um eine statistische Aussagekraft für seltene Allele zu erreichen. Anhand der hier vorgelegten Ergebnisse hat der TNF-alpha-Genotyp weder einen Einfluß auf die Progression der HIV-Erkrankung noch auf die Ausbildung HIV-assoziierter Erkrankungen wie dem Wasting Syndrom oder der HIV-Enzephalopathie. / Objective: We determined whether variation of the tumor necrosis factor-alpha gene had an impact on HIV disease progression or the prevalence of hiv-associated diseases. Methods: The promotor region of the TNF-alpha gene were examined with SSCP analysis for polymorphisms in the promotor region. The most common promotor polymorphisms were characterized with restriction fragment length polymorphism analysis (RFLP). To confirm RFLP results DNA fluorescence sequenzing analyses were performed with selected samples. In all cases with diagnosis of promotor polymorphisms single base transitions from guanine to adenine were confirmed. Results: Statistical analyses correlated the genotypes with different markers for disease progression e.g. CD4-count, the period from ARC to AIDS and the occurance of HIV associated diseases (wasting syndrome, hiv encephalopathy). In none of the statistical analyses significant association with a certain TNF-alpha genotyp could be demonstrated. Conclusion: For some subanalysis the sample sizes were too small in order to be able to make safe statistical statements concerning rare allels. Regarding our results, none of the examined tumor necrosis factor-alpha promotor polymorphisms had an impact on HIV disease progression or the prevalence of hiv-associated diseases.

Chronisch entzündliche Darmerkrankungen stellen eine Gruppe von chronischen, häufig in Schüben verlaufenden Erkrankungen mit rezidivierenden Entzündungen des Gastrointestinaltraktes dar. Es konnte gezeigt werden, dass eine gestörte Barrierefunktion einen wichtigen Schritt für die Pathogenese darstellt und dass das Zytokin Tumornekrosefaktor alpha (TNF) eine entscheidende Rolle dabei spielt. Die Rolle der kleinen GTPase RhoA bei der TNF-induzierten Barrieredysfunktion ist aufgrund der Komplexität der Signalwege nicht vollständig verstanden. Daher sollte der Einfluss von RhoA und der RhoA Effektorkinase PKN auf diese Prozesse in vitro mit Hilfe eines induzierbaren Expressionssystems untersucht werden, welches die kontrollierte Expression einer konstitutiv aktiven (KA) RhoA- und PKN-Mutante sowie einer dominant negativen (DN) PKN-Mutante ermöglichte. Die Induktion der KA RhoA Expression führte zu einer Störung der epithelialen Barriere. Eine simultane Interferon-gamma und TNF-Behandlung resultierte ebenfalls in einer gestörten Barrierefunktion, welche in KA RhoA Zellen weniger stark ausgeprägt war. Die TNF-Behandlung führte zu einer Aktivierung von PKN, weshalb dieses Protein ein Kandidat für die Vermittlung dieser Effekte darstellte. Inhibition von PKN mit Inhibitoren oder der Expression der DN Mutante führten zu einer Aggravierung der TNF-induzierten Barrieredysfunktion, welche durch eine Verringerung des transepithelialen elektrischen Widerstandes und eine erhöhte Ionenpermeabilität charakterisiert war. Diese Veränderungen wurden von einer Erhöhung des Myosin Leichtketten und NF-kappaB p65-Phosphorylierungsniveaus sowie von morphologischen Veränderungen begleitet. Im Gegensatz dazu konnten diese Veränderungen durch die Expression der KA PKN Variante abgeschwächt bzw. verhindert werden. Diese Ergebnisse liefern Hinweise auf eine potenzielle Rolle der RhoA Effektorkinase PKN bei der Modulation der TNF-induzierten Barrieredysfunktion in intestinalen Epithelzellen. / Inflammatory bowel diseases are relapsing systemic inflammatory diseases of the gastrointestinal tract associated with high morbidity and costs. A plethora of studies demonstrated that impaired intestinal barrier function is a key step in the pathogenesis of inflammatory bowel diseases and that the cytokine tumor necrosis factor alphpa (TNF) is of pivotal importance for this effect. Although the small GTPase RhoA has been implicated in the control of tight junction function, its role in TNF induced barrier dysfunction is not entirely understood due to the complexity of its downstream signaling pathways. Therefore, the contribution of RhoA and its effector kinase PKN on TNF induced barrier dysfunction was investigated in vitro. An inducible expression system that allowed the doxycyline controlled expression of a constitutively active (CA) RhoA and PKN mutant as well as a dominant negative (DN) PKN mutant was generated. Induction of CA RhoA expression led to an impaired epithelial barrier. Simultaneous Interferon-gamma and TNF treatment also resulted in barrier perturbation, but this defect was attenuated when CA RhoA was expressed. As treatment with TNF resulted in activation of the RhoA effector kinase PKN, this protein constitutes a candidate molecule for the mediation of these effects. Inhibition of PKN by inhibitory compounds as well as expression of a dominant negative PKN mutant aggravated TNF-induced barrier dysfunction, characterized by a decline in transepithelial electrical resistance and increased ion permeability. These alterations were accompanied by an increase in myosin light-chain and NF-kappaB p65 subunit phosphorylation level as well as morphological changes of the tight junctions. Conversely, expression of a CA PKN mutant attenuated or prevented these changes. These results provide support for a potential role of the RhoA effector kinase PKN in modulating the barrier disrupting effects of TNF in the intestinal epithelium.

O sistema NADPH oxidase humano é responsável pela geração de reativos intermediários do oxigênio e defeitos neste sistema resultam na Doença Granulomatosa Crônica (DGC). Nesta tese de doutorado, investigamos o efeito do IFN-g sobre eventos pós-transcricionais em pacientes com DGC ligada ao X, ocasionada por defeitos de splicing. Os dados obtidos sugerem que o uso do IFN-g in vitro interfere no processamento da mensagem causando aumento da expressão de transcritos do gene CYBB e NCF1 em células B-EBV de indivíduos sadios e pacientes DGC analisados. Observamos também que o IFN-g dimunui a expressão dos genes THOC4 NONO, SF3A1, SRRM1 e UPF3A e promove aumento de expressão de SRSF10, SNRPA1 e C2 em células B-EBV de paciente X-DGC secundária a defeitos de splicing. Identificamos que o IFN-g e o TNF-α aumentam a expressão das proteínas envolvidas no processo do splicing. Concluímos que o IFN-g aumenta a expressão de genes importantes para uma resposta eficiente do sistema imunológico, incluindo os do sistema NADPH oxidase, além de promover aumento da expressão de genes e de proteínas relacionados ao processo de splicing, que podem estar relacionados aos efeitos benéficos observados no uso do IFN-g em pacientes com DGC ligada ao X, ocasionada por defeitos de splicing. / The human phagocyte NADPH oxidase is responsible for the generation of reactive oxygen intermediates and defects in this system result in Chronic Granulomatous Disease (CGD). In this PhD Thesis, we investigated the effect of IFN-g on post-transcriptional events in normal individuals and patients with X-linked CGD, caused by splicing defects. The obtained data suggests that the use of IFN-g in vitro interferes in the message processing causing an increase of expression of CYBB and NCF1 gene transcripts in B-EBV cells of healthy individuals and analyzed CGD patients. We also observed that IFN-g decreases the expression of THOC4, NONO, SF3A1, SRRM1 and UPF3A, and increases the expression of SRSF10, SNRPA1 and C2 genes in cells from X-CGD patients, due to splicing defects. We identified that IFN-g and TNF-α induce expression of proteins involved in the splicing process. We conclude that IFN-g increases the expression of important genes for an effective immune response, including the NADPH oxidase system genes, and promotes augment of gene and protein expression related to the splicing process, which may be related to the beneficial effects related to the use of IFN-g in CGD patient caused by splicing defects.

Les sphingolipides sont une famille de lipides membranaires dotés d'un rôle structural, influant sur les propriétés de la bicouche lipidique, mais ils agissent aussi comme des molécules effectrices au rôle essentiel dans de nombreux aspects de la biologie cellulaire. Les sphingolipides céramide, sphingosine et S1P ont des effets opposés: le céramide et la sphingosine inhibent la prolifération et promeuvent la réponse apoptotique à différents stimulus de stress, la S1P est un stimulateur de la prolifération et de la survie cellulaires. Le céramide peut être produit par la voie de synthèse de novo, et l'hydrolyse de la sphingomyéline membranaire catalysée par les sphingomyélinases. Ces deux voies peuvent être activées par la cytokine pro-inflammatoire TNFa, capable d’induire une perte musculaire et jouant un rôle crucial dans le développement de la cachexie. Nous avons fait l'hypothèse que le céramide, ou un de ses métabolites, peuvent être des médiateurs de la perte musculaire tumeur-induite. Nous avons examiné le rôle du céramide dans l'atrophie induite in vitro par le TNFa chez les myotubes, en utilisant des analogues de céramide et des inhibiteurs du métabolisme sphingolipidique. L'apport de céramides exogènes est capable de reproduire l'effet atrophique du TNFa, ce qui suggère que le céramide peut participer à l'atrophie musculaire. Pour vérifier si les céramides sont les médiateurs de l'atrophie induite par le TNFa, nous avons analysé l'effet d'inhibiteurs ciblant différentes étapes du métabolisme: l'inhibition de la voie de synthèse de novo est incapable de rétablir la taille des myotubes en présence de TNFa, alors que les inhibiteurs de sphingomyélinase neutre suppriment l'atrophie TNFa-induite. L’accumulation de céramide et de sphingosine augmente l’effet pro-atrophique, tandis que la S1P a un effet protecteur. Ces observations montrent que, dans les myotubes, le céramide, ou un métabolite produits par la voie de la sphingomyélinase neutre en réponse à une stimulation par le TNFa, participent à l'atrophie des cellules. Pour évaluer le rôle in vivo des sphingolipides, nous avons traité la souris BalbC porteuse d’un carcinome C26 avec myriocine, inhibiteur de la synthèse de novo, capable d'induire une déplétion du muscle en sphingolipides, Ce traitement protège partiellement les souris contre la perte de poids corporel et de poids des muscles induite par la tumeur, sans affecter la taille de celle-ci. De plus, la myriocine réverse significativement la perte de taille des fibres musculaires et réduit l'expression des atrogenes, ce qui montre qu'elle protège le muscle contre l'atrophie. Ces résultats suggèrent fortement que le céramide, ou un métabolite sphingolipidique en aval, est impliqué dans l'atrophie musculaire tumeur-induite. La voie des sphingolipides apparaît donc comme une nouvelle cible potentielle d'interventions pharmacologiques visant à protéger le tissu musculaire contre l'atrophie. / The sphingolipids are a family of membrane lipids with only a structural role, influencing lipid bilayer properties, but they also act as effector molecules with essential roles in many aspects of cell biology. The sphingolipids ceramide, sphingosine and S1P have shown opposite effects: whereas ceramide and sphingosine usually inhibit proliferation and promote apoptotic responses to different stress stimuli, S1P is known to stimulate cell growth, and promote cell survival. Ceramide can be produced through the de novo synthesis pathway, and by membrane sphingomyelin hydrolysis catalyzed by sphingomyelinases. Both pathways can be activated by the pro-inflammatory cytokine TNFa. Because this cytokine has been shown to promote muscle loss and seems to be crucial in the development of cachexia, we hypothesized that the formation of ceramide, or a metabolite, can be involved in tumor-induced muscle wasting. We investigated the role of ceramide in the in vitro atrophic effects of TNFa on differentiated C2C12 myotubes, by using cell permeant ceramides and inhibitors of sphingolipid metabolism. We observed that TNFa atrophic effects, as evaluated by the reduction in myotube area, are mimicked by exogenous ceramides, supporting the idea that ceramide can participate in muscle atrophy. To verify if ceramide is a mediator of TNFa-induced atrophy, and to identify the metabolites potentially involved, we analyzed the effects of drugs able to block sphingolipid metabolism at different steps: the inhibition of de novo synthesis pathway was unable to restore myotube size in the presence of TNFa whereas the inhibitors of neutral sphingomyelinases reversed TNFa-induced atrophy. Moreover, an accumulation of ceramide and sphingosine induced pro-atrophic effects, whereas sphingosine-1-phosphate had a protective effect. These observations establish that in C2C12 myotubes, ceramide or other downstream metabolites such as sphingosine, produced by the neutral sphingomyelinase pathway in response to TNFa stimulation, participate in cell atrophy. To evaluate the in vivo role of sphingolipids, we treated BalbC mice carrying C26 adenocarcinoma woth Myriocin, an inhibitor of the de novo pathway of ceramide synthesis, that is able to deplete muscle tissue in all sphingolipids, was administered daily to the animals. This treatment partially protected animals against tumor-induced loss of body weight and muscle weight, without affecting the size of tumors. Moreover, myriocin treatment significantly reversed the decrease in myofiber size associated with tumor development, and reduced the expression of atrogenes Foxo3 and Atrogin-1, showing that it was able to protect against muscle atrophy. These results strongly suggest that ceramide, or a downstream sphingolipid metabolite, is involved in tumor-induced muscle atrophy. The sphingolipid pathway thus appears as a new potential target of pharmacological interventions aiming at protecting muscle tissue against atrophy.

Le muscle squelettique fait preuve d'une remarquable plasticité en réponse aux changements physiologiques, comme l’activité physique, et aux situations pathologiques. Il subit notamment une atrophie sévère lors de la cachexie qui accompagne diverses pathologies chroniques comme le cancer, le SIDA, etc. L’atrophie musculaire est aussi une composante de la sarcopénie qui survient lors du vieillissement normal, et se caractérise par un déclin de la force et de la masse musculaire. L'atrophie musculaire, qui entraîne une augmentation de la mortalité et diminue l’efficacité des traitements, constitue donc un problème de santé majeur.La fonte musculaire se caractérise par une altération de l’équilibre entre synthèse et dégradation protéiques dans les fibres adultes. Des taux particulièrement élevés de cytokines circulantes, dont le TNFα, qui affectent l’homéostasie du muscle via différentes voies de signalisation, semblent être à l’origine de l'atrophie. Les mécanismes de la réponse atrophique musculaire à ces taux circulants élevés sont cependant mal définis. Le TNFα a des effets complexes. Il peut activer de multiples voies de signalisation, parmi lesquelles l'induction de la synthèse de sphingolipides, et plus particulièrement de céramides, par la voie de novo et par l'activation des sphingomyélinases. Au niveau musculaire, les céramides sont connus pour leurs effets sur la signalisation de l'insuline, sur l'apoptose et sur la différenciation myogénique. Par contre, leur implication dans le cadre de l'atrophie n'avait jamais été prise en compte. L’objectif de ce travail a été dans un premier temps de démontrer le rôle des céramides dans l’atrophie. Dans un deuxième temps, nous avons caractérisé la voie de signalisation par laquelle l’augmentation intramusculaire de céramide induite par le TNFα aboutit à une chute de la synthèse protéique, couplée à une augmentation de la protéolyse. Dans ce but, nous avons mis au point des modèles in vitro d'atrophie, impliquant des myotubes traités par des concentrations physiologiques de TNF. Nous avons en parallèle étudié un modèle in vivo de cachexie induite chez la souris par l'implantation d’un adénocarcinome C26. L’analyse des sphingolipides nous a permis de montrer l’augmentation des taux de céramides concomitante à l’atrophie générée in vitro et in vivo. Le rôle des céramides dans l’atrophie a été démontré par l’effet protecteur des inhibiteurs de leur synthèse, dans les modèles in vitro et in vivo. Nous montrons de plus dans un modèle in vitro que les effets atrophiques des céramides sont dus à l’inhibition de la voie de signalisation Phospholipase D/mTOR/Akt. Nos résultats nous ont permis de prouver le rôle des sphingolipides dans le contrôle de l’homéostasie protéique du muscle. La modulation du métabolisme des sphingolipides apparaît donc comme une nouvelle cible thérapeutique prometteuse dans le traitement de la perte musculaire associée à diverses pathologies. / Skeletal muscle demonstrated a remarkable plasticity in response to physiological changes, such as physical activity, and pathological situations. He suffered such severe atrophy during cachexia that accompanies various pathologies such as cancer, AIDS, etc.. Muscle atrophy is also a component of sarcopenia that occurs during normal aging, and is characterized by a decline in strength and muscle mass. Muscle atrophy, which leads to increased mortality and decreased treatment efficacy, thus constitutes a health problem majeur.La muscle wasting is characterized by an impaired balance between protein synthesis and degradation in adult fibers. Particularly high levels of circulating cytokines, including TNF, which affect muscle homeostasis via different signaling pathways appear to be the cause of atrophy. Mechanisms of muscle atrophy response to these elevated circulating levels are however unclear. TNFa has complex effects. It may activate multiple signaling pathways, including the induction of the synthesis of sphingolipids, especially ceramides, for the de novo pathway and the activation of sphingomyelinases. In muscle, ceramides are known for their effects on insulin signaling on apoptosis and myogenic differentiation. By cons, their involvement in the context of atrophy was never taken into account. The objective of this work was firstly to demonstrate the role of ceramides in atrophy. In a second step, we characterized the signaling pathway by which increased intramuscular ceramide induced by TNF leads to a fall in protein synthesis, coupled with an increase in proteolysis. For this purpose, we have developed in vitro models of atrophy involving myotubes treated with physiological concentrations of TNF . We studied in parallel an in vivo model of cachexia induced in mice by implantation of adenocarcinoma C26. Analysis of sphingolipids we showed increased levels of ceramide concomitant atrophy generated in vitro and in vivo. The role of ceramide in atrophy has been demonstrated by the protective effect of inhibitors of their synthesis in the in vitro and in vivo. We show further in an in vitro model that atrophic effects of ceramides are due to inhibition of phospholipase D signaling pathway / mTOR / Akt. Our results allowed us to prove the role of sphingolipids in the homeostatic control of muscle protein. Modulation of sphingolipid metabolism appears to be a promising new therapeutic target in the treatment of muscle wasting associated with various pathologies.