Éditeur(s) : HAL CCSD
Résumé : International audience
Industrial use of aniline is increasing worldwide with production estimated to surpass 5.6 million metric tons in 2016. Exposure to aniline occurs via air, diet and water augmenting the risk of exposing a large number of individuals. Early observations suggest that aniline is metabolised to paracetamol/acetaminophen, likely explaining the omnipresence of low concentrations of paracetamol in European populations. This is of concern as recent studies implicate paracetamol as a disrupter of reproduction. Here we show through steroidogenic profiling that exposure to aniline led to increased levels of the Δ4 steroids, suggesting that the activity of CYP21 was decreased. By contrast, paracetamol decreased levels of androgens likely through inhibition of CYP17A1 activity. We confirm that aniline in vivo is rapidly converted to paracetamol by the liver. Intrauterine exposure to aniline and paracetamol in environmental and pharmaceutical relevant doses resulted in shortening of the anogenital distance in mice, a sensitive marker of fetal androgen levels that in humans is associated with reproductive malformations and later life reproductive disorders. In conclusion, our results provide evidence for a scenario where aniline, through its conversion into anti-androgenic paracetamol, impairs male reproductive development
Toxicological Sciences: An Official Journal of the Society of Toxicology

hal-01187305
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187305
DOI : 10.1093/toxsci/kfv179
PUBMED : 26259604

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Predictive toxicology aims at developing methodologies to relate the results obtained from in vitro experiments to in vivo exposure. In the case of polycyclic aromatic hydrocarbons (PAHs), a substantial amount of knowledge on effects and modes of action has been recently obtained from in vitro studies of gene expression. In the current study, we built a physiologically based toxicokinetic (PBTK) model to relate in vivo and in vitro gene expression in case of exposure to benzo(a)pyrene (BaP), a referent PAH. This model was calibrated with two toxicokinetic datasets obtained on rats exposed either through intratracheal instillation or through intravenous administration and on an in vitro degradation study. A good agreement was obtained between the model's predictions and the concentrations measured in target organs, such as liver and lungs. Our model was able to relate correctly the gene expression for two genes targeted by PAHs, measured in vitro on primary human macrophages and in vivo in rat macrophages after exposure to BaP. Combining in vitro studies and PBTK modeling is promising for PAH risk assessment, especially for mixtures which are more efficiently studied in vitro than in vivo.
Toxicology Letters

hal-00873317
https://hal.archives-ouvertes.fr/hal-00873317
https://hal.archives-ouvertes.fr/hal-00873317/document
DOI : 10.1016/j.toxlet.2010.11.017
PUBMED : 21134426

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Hand disinfection with alcohols-based hand rubs (ABHRs) are known to be the most effective measure to prevent nosocomial infections in healthcare. ABHRs contain on average 70% by weight of one or more alcohols. During the hand rubbing procedure, users are exposed to these alcohols not only through dermal contact, but also via inhalation, due to the physical and chemical properties of alcohols volatilizing from alcoholic solutions or gels into the air. Ethanol ingestion is well known to increase risks of several diseases (affecting the pancreas, liver, cardiovascular system…), but there is a lack of knowledge about the effects of exposure to other alcohols (including n- or isopropanol) via inhalation and dermal contact, despite the worldwide use of ABHRs. This work aims at discussing possible health effects related to unintentional alcoholization (via inhalation and dermal contact) from professional ABHR usage to suggest the need for more research in this area (but not to question the value of ABHRs). Based upon an average of 30 hand rubbings per healthcare professional per day, it can be assumed that a healthcare worker may be exposed to a maximum 5,500 mg/m(3) per work shift, five times above the recommended occupational time weighted average limit. Thus, in order to answer the question posed in the title, studies on spatial and temporal variability of alcohol emission from ABHRs in real world situations and studies on certain high risk individuals are needed.
ISSN: 1660-4601

hal-01122305
https://hal.archives-ouvertes.fr/hal-01122305
PUBMED : 20948945
DOI : 10.3390/ijerph7083038
PUBMEDCENTRAL : PMC2954566

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
We show that MLCK (myosin light chain kinase) plays a key role in cell cycle progression of hepatocytes: either chemical inhibitor ML7 or RNA interference led to blockade of cyclin D1 expression and DNA replication, providing evidence that MLCK regulated S phase entry. Conversely, inhibition of RhoK by specific inhibitor Y27632 or RhoK dominant-negative vector did not influence progression in late G1 and S phase entry. Inhibition of either MLCK or RhoK did not block ERK1/2 phosphorylation, whereas MLCK regulated ERK2-dependent p70S6K activation. In addition, DNA synthesis was reduced in hepatocytes treated with p70S6K siRNA, demonstrating the key role played by the kinase in S phase entry. Interestingly, after the G1/S transition, DNA replication in S phase was no longer dependent on MLCK activity. We strengthened this result by ex vivo experiments and evidenced an MLCK-dependent window in late G1 phase of regenerating liver after two-thirds partial hepatectomy. In conclusion, our results underline an MLCK-dependent restriction point in G1/S transition, occurring downstream of ERK2 through the regulation of p70S6K activation, and highlighting a new signaling pathway critical for hepatocyte proliferation.
ISSN: 0270-9139

hal-00702089
https://hal.archives-ouvertes.fr/hal-00702089
DOI : 10.1002/hep.21222
PUBMED : 16799973

Éditeur(s) : HAL CCSD American Society for Biochemistry and Molecular Biology
Résumé : International audience
2-Amino-9H-pyrido[2,3-b]indole (AαC) is a carcinogenic heterocyclic aromatic amine (HAA) that arises in tobacco smoke. UDP-glucuronosyltransferases (UGTs) are important enzymes that detoxicate many procarcinogens, including HAAs. UGTs compete with P450 enzymes, which bioactivate HAAs by N-hydroxylation of the exocyclic amine group; the resultant N-hydroxy-HAA metabolites form covalent adducts with DNA. We have characterized the UGT-catalyzed metabolic products of AαC and the genotoxic metabolite 2-hydroxyamino-9H-pyrido[2,3- b]indole (HONH-AαC) formed with human liver microsomes, recombinant human UGT isoforms, and human hepatocytes. The structures of the metabolites were elucidated by 1H NMR and mass spectrometry. AαC and HONH-AαC underwent glucuronidation by UGTs to form, respectively, N 2-(β- D-glucosidurony1)-2-amino-9H-pyrido[2,3-b]indole (AαC-N 2-Gl) and N 2-(β-D-glucosidurony1)-2-hydroxyamino-9H-pyrido[2,3-b] indole (AαC-HON 2-Gl). HONH-AαC also underwent glucuronidation to form a novel O-linked glucuronide conjugate, O-(β-D-glucosidurony1)-2-hydroxyamino-9H-pyrido[2,3-b]indole (AαC-HN 2-O-Gl). AαC-HN 2-O-Gl is a biologically reactive metabolite and binds to calf thymus DNA (pH 5.0 or 7.0) to form the N-(deoxyguanosin-8-yl)-AαC adduct at 20-50-fold higher levels than the adduct levels formed with HONH-AαC. Major UGT isoforms were examined for their capacity to metabolize AαC and HONH-AαC. UGT1A4 was the most catalytically efficient enzyme (V max/K m) at forming AαC-N 2-Gl (0.67 μl*min -1*mg of protein -1), and UGT1A9 was most catalytically efficient at forming AαC-HN-O-Gl (77.1 μl*min -1*mg of protein -1), whereas UGT1A1 was most efficient at forming AαC-HON 2-Gl (5.0 μl*min -1*mg of protein -1). Human hepatocytes produced AαC-N 2-Gl and AαC-HN 2-O-Gl in abundant quantities, but AαC-HON 2-Gl was a minor product. Thus, UGTs, usually important enzymes in the detoxication of many procarcinogens, serve as a mechanism of bioactivation of HONH-AαC. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
ISSN: 0021-9258

hal-00696860
https://hal-anses.archives-ouvertes.fr/hal-00696860
DOI : 10.1074/jbc.M111.320093
PUBMED : 22393056

Éditeur(s) : HAL CCSD Elsevier
Résumé : Rh (Rhesus) is a major blood group system in man, which is clinically significant in transfusion medicine. Rh antigens are carried by an oligomer of two major erythroid specific polypeptides, the Rh (D and CcEe) proteins and the RhAG glycoprotein, that shared a common predicted structure with 12 transmembrane a-helices (M0 to M11). Non erythroid homologues of these proteins have been identified (RhBG and RhCG), notably in diverse organs specialized in ammonia production and excretion, such as kidney, liver and intestine. Phylogenetic studies and experimental evidence have shown that these proteins belong to the Amt/Mep/Rh protein superfamily of ammonium/methylammonium permease, but another view suggests that Rh proteins might function as CO2 gas channels. Until recently no information on the structure of these proteins were available. However, in the last two years, new insight has been gained into the structural features of Rh proteins (through the determination of the crystal structures of bacterial AmtB and archeaebacterial Amt-1. Here, models of the subunit and oligomeric architecture of human Rh proteins are proposed, based on a refined alignment with and crystal structure of the bacterial ammonia transporter AmtB, a member of the Amt/ Mep/Rh superfamily. This alignment was performed considering invariant structural features, which were revealed through Hydrophobic Cluster Analysis, and led to propose alternative predictions for the less conserved regions, particularly in the N-terminal sequences. The Rh models, on which an additional Rh-specific, N-terminal helix M0 was tentatively positioned, were further assessed through the consideration of biochemical and immunochemical data, as well as of stereochemical and topological constraints. These models highlighted some Rh specific features that have not yet been reported. Among these, are the prediction of some critical residues, which may play a role in the channel function, but also in the stability of the subunit structure and oligomeric assembly. These results provide a basis to further understand the structure/function relationships of Rh proteins, and the alterations occurring in variant phenotypes.
ISSN: 1246-7820

hal-00068842
https://hal.archives-ouvertes.fr/hal-00068842

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Hepatitis B virus (HBV) infection is a major public health problem. Recently, the human liver bile acid transporter Na+/taurocholate cotransporting polypeptide (NTCP) has been identified as an HBV specific receptor. NTCP expression is known to be strongly regulated by IL-6. This study was aimed at characterizing the effect of IL-6 on HBV entry. HBV entry was inhibited by up to 90% when cells were pretreated with IL-6 as shown by a strong inhibition of long term HBsAg secretion. This effect was confirmed by showing a severe reduction of intracellular HBV cccDNA. In parallel, we observed a 98% decrease in NTCP mRNA steady state level and an 80% reduction in NTCP-mediated taurocholate uptake. IL-6-mediated inhibition of NTCP-mediated taurocholate uptake and viral entry exhibited similar dose-dependence and kinetics while restoration of NTCP expression suppressed the inhibitory effect of IL-6. NTCP-mediated HBV entry is therefore markedly inhibited by IL-6.
ISSN: 0042-6822

hal-01134184
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134184
DOI : 10.1016/j.virol.2015.02.026
PUBMED : 25765005

Éditeur(s) : HAL CCSD BMJ Publishing Group
Résumé : International audience
BACKGROUND: Chronic HCV infection is associated with the development of hepatic fibrosis. The direct role of HCV in the fibrogenic process is unknown. Specifically, whether HCV is able to infect hepatic stellate cells (HSCs) is debated. OBJECTIVE: To assess whether human HSCs are susceptible to HCV infection. DESIGN: We combined a set of original HCV models, including the infectious genotype 2a JFH1 model (HCVcc), retroviral pseudoparticles expressing the folded HCV genotype 1b envelope glycoproteins (HCVpp) and a subgenomic genotype 1b HCV replicon, and two relevant cellular models, primary human HSCs from different patients and the LX-2 cell line, to assess whether HCV can infect/replicate in HSCs. RESULTS: In contrast with the hepatocyte cell line Huh-7, neither infectious HCVcc nor HCVpp infected primary human HSCs or LX-2 cells. The cellular expression of host cellular factors required for HCV entry was high in Huh-7 cells but low in HSCs and LX-2 cells, with the exception of CD81. Finally, replication of a genotype 2a full-length RNA genome and a genotype 1b subgenomic replicon was impaired in primary human HSCs and LX-2 cells, which expressed low levels of cellular factors known to play a key role in the HCV life-cycle, suggesting that human HSCs are not permissive for HCV replication. CONCLUSIONS: Human HSCs are refractory to HCV infection. Both HCV entry and replication are deficient in these cells, regardless of the HCV genotype and origin of the cells. Thus, HCV infection of HSCs does not play a role in liver fibrosis. These results do not rule out a direct role of HCV infection of hepatocytes in the fibrogenic process.
ISSN: 0017-5749

hal-01063909
https://hal.archives-ouvertes.fr/hal-01063909
DOI : 10.1136/gutjnl-2013-305634
PUBMED : 25063678

Éditeur(s) : HAL CCSD
Résumé : International audience
The alarmin IL-33 has been described to be upregulated in human and murine viral hepatitis. However, the role of endogenous IL-33 in viral hepatitis remains obscure. We aimed to decipher its function by infecting IL-33-deficient mice (IL-33 KO) and their wild-type (WT) littermates with pathogenic mouse hepatitis virus (L2-MHV3). The IL-33 KO mice were more sensitive to L2-MHV3 infection exhibiting higher levels of AST/ALT, higher tissue damage, significant weight loss, and earlier death. An increased depletion of B and T lymphocytes, NKT cells, dendritic cells, and macrophages was observed 48 h postinfection (PI) in IL-33 KO mice than that in WT mice. In contrast, a massive influx of neutrophils was observed in IL-33 KO mice at 48 h PI. A transcriptomic study of inflammatory and cell-signaling genes revealed the overexpression of IL-6, TNFα, and several chemokines involved in recruitment/activation of neutrophils (CXCL2, CXCL5, CCL2, and CCL6) at 72 h PI in IL-33 KO mice. However, the IFNγ was strongly induced in WT mice with less profound expression in IL-33 KO mice demonstrating that endogenous IL-33 regulated IFNγ expression during L2-MHV3 hepatitis. In conclusion, we demonstrated that endogenous IL-33 had multifaceted immunoregulatory effect during viral hepatitis via induction of IFNγ, survival effect on immune cells, and infiltration of neutrophils in the liver.
Mediators of Inflammation

hal-01544268
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01544268
DOI : 10.1155/2017/1359064
PUBMED : 28607531
PUBMEDCENTRAL : PMC5457781

Éditeur(s) : HAL CCSD
Résumé : International audience
INTRODUCTION: Alpha-1 antitrypsin, secreted by the liver, inhibits neutrophil elastase. Its deficiency favours the development of emphysema. Restoring a "protective" serum level in deficient patients should make it possible to inhibit the development of emphysema. STATE OF THE ART: Human plasma-derived alpha-1 antitrypsin is a blood-derived drug sold in France under the name Alfalastin(®). The recommended posology is an I.V. administration of 60mg/kg once a week. Human plasma-derived alpha-1 antitrypsin restores anti-elastase protection in the lower lung and prevents experimental emphysema induced by the elastasis of human neutrophils in hamster. The low number of patients with alpha-1 antitrypsin deficiency is one of the difficulties to perform sufficiently powerful randomised studies. However, randomised studies have reported the efficacy of human plasma-derived alpha-1 antitrypsin perfusions on mortality, FEV1 decline and the frequency of exacerbations. Randomised control trials have demonstrated the efficacy of human plasma-derived alpha-1 antitrypsin perfusions on the loss of lung density assessed by CT scan. CONCLUSION: Augmentation therapy is simple in its conception and implementation, but it is expensive. However, there are currently no other solutions.
Revue Des Maladies Respiratoires

hal-01146841
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146841
DOI : 10.1016/j.rmr.2014.10.001
PUBMED : 25908241

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
: Previously, we demonstrated that eicosapentaenoic acid enhanced ethanol-induced oxidative stress and cell death in primary rat hepatocytes via an increase in membrane fluidity and lipid raft clustering. In this context, another n-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), was tested with a special emphasis on physical and chemical alteration of lipid rafts. Pretreatment of hepatocytes with DHA reduced significantly ethanol-induced oxidative stress and cell death. DHA protection could be related to an alteration of lipid rafts. Indeed, rafts exhibited a marked increase in membrane fluidity and packing defects leading to the exclusion of a raft protein marker, flotillin. Furthermore, DHA strongly inhibited disulfide bridge formation, even in control cells, thus suggesting a disruption of protein-protein interactions inside lipid rafts. This particular spatial organization of lipid rafts due to DHA subsequently prevented the ethanol-induced lipid raft clustering. Such a prevention was then responsible for the inhibition of phospholipase C-γ translocation into rafts, and consequently of both lysosome accumulation and elevation in cellular low-molecular-weight iron content, a prooxidant factor. In total, the present study suggests that DHA supplementation could represent a new preventive approach for patients with alcoholic liver disease based upon modulation of the membrane structures.
ISSN: 0278-6915

hal-00860153
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00860153
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00860153/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00860153/file/Sergent-et-al-incl-figures-accepted.pdf
DOI : 10.1016/j.fct.2013.07.061

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Bone Morphogenetic Protein 9 (BMP9) has been recently found to be the physiological ligand for the activin receptor-like kinase 1 (ALK1), and to be a major circulating vascular quiescence factor. Moreover, a soluble chimeric ALK1 protein (ALK1-Fc) has recently been developed and showed powerful anti-tumor growth and anti-angiogenic effects. However, not much is known concerning BMP9. This prompted us to investigate the human endogenous sources of this cytokine and to further characterize its circulating form(s) and its function. Analysis of BMP9 expression reveals that BMP9 is produced by hepatocytes and intrahepatic biliary epithelial cells. Gel filtration analysis combined with ELISA and biological assays demonstrate that BMP9 circulates in plasma (1) as an unprocessed inactive form that can be further activated by furin a serine endoprotease, and (2) as a mature and fully active form (composed of the mature form associated with its prodomain). Analysis of BMP9 circulating levels during mouse development demonstrates that BMP9 peaks during the first 3 weeks after birth and then decreases to 2 ng/mL in adulthood. We also show that circulating BMP9 physiologically induces a constitutive Smad1/5/8 phosphorylation in endothelial cells. Taken together, our results argue for the role of BMP9 as a hepatocyte-derived factor, circulating in inactive (40%) and active (60%) forms, the latter constantly activating endothelial cells to maintain them in a resting state.
ISSN: 1420-682X

hal-00681969
https://hal.archives-ouvertes.fr/hal-00681969
DOI : 10.1007/s00018-011-0751-1
PUBMED : 21710321

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Introduction: The selection of patients with metastatic clear cell renal cell carcinoma (ccRCC) who may benefit from targeted tyrosine kinase inhibitors has been a challenge, even more so now with the advent of new therapies. Hilar fat infiltration (HFI) is a validated prognostic factor in nonmetastatic ccRCC (TNM 2009 staging system) but has never been studied in metastatic patients. We aimed to assess its phenotype and prognostic effect in patients with metastatic ccRCC treated with first-line sunitinib.Materials and methods: In a multicentric study, we retrospectively included 90 patients and studied the corresponding ccRCC at the pathological, immunohistochemical, and molecular levels. Patient and tumor characteristics were compared using univariate and multivariate analysis. All the features were then studied by Cox models for prognostic effect.Results: HFI was found in 42 patients (46.7%), who had worse prognosis (Heng criteria) (P = 0.003), liver metastases (P = 0.036), and progressive diseases at first radiological evaluation (P = 0.024). The corresponding ccRCC was associated with poor pathological prognostic factors that are well known in nonmetastatic ccRCC. For these patients, median progression-free survival was 4 months vs. 13 months (P = 0.02), and median overall survival was 14 months vs. 29 months (P = 0.006). In a multivariate Cox model integrating all the variables, only poor prognosis, according to the Heng criteria and HFI, remained independently associated with both progression-free survival and overall survival.Conclusion: HFI was demonstrated for the first time to be an independent poor prognostic factor. Its potential role in predicting resistance to antiangiogenic therapy warrants further investigation.
ISSN: 1078-1439

hal-01632553
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01632553
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01632553/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01632553/file/Hilar%20fat%20infiltration_accepted.pdf
DOI : 10.1016/j.urolonc.2017.05.015

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The catecholamine epinephrine is known to repress expression of hepatic drug metabolizing enzymes such as cytochromes P-450. The present study was designed to determine whether epinephrine may also target expression of main hepatic drug transporters, that play a major role in liver detoxification and are commonly coordinately regulated with drug detoxifying enzymes. Treatment of primary human hepatocytes with 10 mu M epinephrine for 24 h repressed mRNA expression of various transporters, such as the sinusoidal influx transporters NTCP, OATP1B1, OATP2B1, OAT2, OAT7 and OCT1 and the efflux transporters MRP2, MRP3 and BSEP, whereas it induced that of MDR1, but failed to alter that of BCRP. Most of these changes in transporter mRNA levels were also found in epinephrine-exposed human highly-differentiated hepatoma HepaRG cells, which additionally exhibited reduced protein expression of OATP2B1 and MRP3, increased expression of P-glycoprotein and decreased transport activity of NTCP, OATPs and OCT1. Epinephrine effects towards transporter mRNA expression in human hepatocytes were next shown to be correlated to those of the selective beta 2-adrenoreceptor (ADR) agonist fenoterol, of the adenylate cyclase activator forskolin and of the cAMP analogue 8-bromo-cAMP. In addition, the non-selective beta-ADR antagonist carazolol and the selective beta 2-ADR antagonist ICI-118,551, unlike the alpha-ADR antagonist phentolamine, suppressed epinephrine -mediated repressions of transporter mRNA expression. Taken together, these data indicate that epinephrine regulates in vitro expression of main hepatic drug transporters in a beta 2-ADR/adenylate cyclase/cAMP-dependent manner. Hepatic drug transport appears therefore as a target of the beta 2-adrenergic system, which may have to deserve attention for drugs interacting with beta 2-ADRs.
ISSN: 0928-0987

hal-01578583
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01578583
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01578583/file/Mayati%20et%20al.%20-%20%CE%B22-adrenergic%20receptor-mediated%20in%20vitro%20regulatio.pdf
DOI : 10.1016/j.ejps.2017.06.010
PUBMED : 28603032

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
Polarization dependence second harmonic generation (P-SHG) microscopy is gaining increase popularity for in situ quantification of fibrillar protein architectures. In this report, we combine P-SHG microscopy, new linear least square (LLS) fitting and modeling to determine and convert the complex second-order non-linear optical anisotropy parameter ρ of several collagen rich tissues into a simple geometric organization of collagen fibrils. Modeling integrates a priori knowledge of polyhelical organization of collagen molecule polymers forming fibrils and bundles of fibrils as well as Poisson photonic shot noise of the detection system. The results, which accurately predict the known sub-microscopic hierarchical organization of collagen fibrils in several tissues, suggest that they can be subdivided into three classes according to their microscopic and macroscopic hierarchical organization of collagen fibrils. They also show, for the first time to our knowledge, intrahepatic spatial discrimination between genuine fibrotic and non-fibrotic vessels. CCl 4-treated livers are characterized by an increase in the percentage of fibrotic vessels and their remodeling involves peri-portal compaction and alignment of collagen fibrils that should contribute to portal hypertension. This integrated P-SHG image analysis method is a powerful tool that should open new avenue for the determination of pathophysiological and chemo-mechanical cues impacting collagen fibrils organization.
ISSN: 2045-2322

hal-01592192
https://hal.archives-ouvertes.fr/hal-01592192
https://hal.archives-ouvertes.fr/hal-01592192/document
https://hal.archives-ouvertes.fr/hal-01592192/file/s41598-017-12398-0.pdf
DOI : 10.1038/s41598-017-12398-0

Éditeur(s) : HAL CCSD Springer Verlag (Germany) Springer Verlag
Résumé : International audience
Apoptosis has emerged as a fundamental process important in tissue homeostasis, immune response, and during development. CD95 (also known as Fas), a member of the tumor necrosis factor receptor (TNF-R) superfamily, has been initially cloned as a death receptor. Its cognate ligand, CD95L, is mainly found at the plasma membrane of activated T-lymphocytes and natural killer cells where it contributes to the elimination of transformed and infected cells. According to its implication in the immune homeostasis and immune surveillance, and since several malignant cells of various histological origins exhibit loss-of-function mutations, which cause resistance towards the CD95-mediated apoptotic signal, CD95 has been classified as a tumor suppressor gene. Nevertheless, this assumption has been recently challenged, as in certain pathophysiological contexts, CD95 engagement transmits non-apoptotic signals that promote inflammation, carcinogenesis or liver/peripheral nerve regeneration. The focus of this review is to discuss these apparent contradictions of the known function(s) of CD95.
ISSN: 1420-682X

hal-00682466
https://hal.archives-ouvertes.fr/hal-00682466
DOI : 10.1007/s00018-011-0866-4
PUBMED : 22042271

Éditeur(s) : HAL CCSD
Résumé : International audience
Lewis blood group specificities are detected in the liver Fluke: Fasciola hepatica. Such specificities had never been reported in nature, other than in the human body. The investigation of this phenomenon might contribute to a better understanding of the mechanisms involved in parasite-host relationship.
C R Seances Acad Sci D

hal-00715437
https://hal.univ-antilles.fr/hal-00715437
PUBMED : 120793

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Human hepatocytes cultured in a monolayer configuration represent a well-established in vitro model in liver toxicology, notably used in drug transporter studies. Polarized status of drug transporters, i.e., their coordinated location at sinusoidal or canalicular membranes, remains however incompletely documented in these cultured hepatocytes. The present study was therefore designed to analyze transporter expression and location in such cells. Most of drug transporters were first shown to be present at notable mRNA levels in monolayer-cultured human hepatocytes. Cultured human hepatocytes, which morphologically exhibited bile canaliculi-like structures, were next demonstrated, through immunofluorescence staining, to express the influx transporters organic anion transporting polypeptide (OATP) 1B1, OATP2B1 and organic cation transporter (OCT) 1 and the efflux transporter multidrug resistance-associated protein (MRP) 3 at their sinusoidal pole. In addition, the efflux transporters P-glycoprotein and MRP2 were detected at the canalicular pole of monolayer-cultured human hepatocytes. Moreover, canalicular secretion of reference substrates for the efflux transporters bile salt export pump, MRP2 and P-glycoprotein as well as sinusoidal drug transporter activities were observed. This polarized and functional expression of drug transporters in monolayer-cultured human hepatocytes highlights the interest of using this human in vitro cell model in xenobiotic transport studies.
ISSN: 0887-2333

hal-01141725
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01141725
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01141725/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01141725/file/Polarized%20location%20of%20SLC.pdf
DOI : 10.1016/j.tiv.2015.03.019

Éditeur(s) : HAL CCSD
Résumé : International audience
Necroptosis is a regulated form of cell death involved in several disease models including in particular liver diseases. Receptor-interacting protein kinases, RIPK1 and RIPK3, are the main serine/threonine kinases driving this cell death pathway. We screened a noncommercial, kinase-focused chemical library which allowed us to identify Sibiriline as a new inhibitor of necroptosis induced by tumor necrosis factor (TNF) in Fas-associated protein with death domain (FADD)-deficient Jurkat cells. Moreover, Sib inhibits necroptotic cell death induced by various death ligands in human or mouse cells while not protecting from caspase-dependent apoptosis. By using competition binding assay and recombinant kinase assays, we demonstrated that Sib is a rather specific competitive RIPK1 inhibitor. Molecular docking analysis shows that Sib is trapped closed to human RIPK1 adenosine triphosphate-binding site in a relatively hydrophobic pocket locking RIPK1 in an inactive conformation. In agreement with its RIPK1 inhibitory property, Sib inhibits both TNF-induced RIPK1-dependent necroptosis and RIPK1-dependent apoptosis. Finally, Sib protects mice from concanavalin A-induced hepatitis. These results reveal the small-molecule Sib as a new RIPK1 inhibitor potentially of interest for the treatment of immune-dependent hepatitis. © 2017 Federation of European Biochemical Societies
ISSN: 1742464X

hal-01616420
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616420
DOI : 10.1111/febs.14176
PUBMED : 28715128

Éditeur(s) : HAL CCSD
Résumé : Hepatitis C virus (HCV) is one of the leading causes of hepatocellular carcinoma. Therapeutic treatment against the virus has been recently improved by a tritherapy including pegylated interferon, ribavirin and antiviral protease. Nevertheless, the importance of side effects and the emergence of resistant mutants require the development of new antivirals. In this context, our team has recently discovered that Type III phosphatidylinositol 4-kinases (PI4KIIIα and PI4KIIIβ) are essential for the propagation of the virus in a human hepatic cell line at the entry and replication steps. To further characterize these potential therapeutic targets, we investigate the implication of these kinases during the HCV entry, using primary human hepatocytes, a model closer to the in vivo conditions. Two lines of research were developed: Verification of the importance of the kinase activity of PI4KIIIs during HCV entry in primary human hepatocytes, through a chemical approach; Validation of the involvement of these kinases and their enzymatic activity during viral entry through a genetic approach based on RNA interference and phenotype rescue. In parallel, we studied the expression of PI4KIIIα in liver diseases. Our results suggest the involvement of PI4KIIIα in HCV entry; the involvement of PI4KIIIIβ needs to be confirmed. The analysis of PI4KIIIα expression in hepatocellular carcinoma led us to propose this kinase as a new molecular marker, which could improve the already established prognosis models and could lead to the development of new therapeutic approaches.
Le virus de l’hépatite C (VHC) est l’un des principaux facteurs étiologiques du carcinome hépatocellulaire. Le traitement des hépatites virales C a été récemment amélioré grâce à une trithérapie (interféron, ribavirine et anti-protéase virale). Néanmoins l’importance des effets secondaires et l’émergence de mutants résistants nécessitent de découvrir de nouveaux antiviraux. Dans ce contexte, notre équipe a récemment découvert que les phosphatidylinositol 4-kinases de type III (PI4KIIIα et PI4KIIIβ) étaient indispensables à la propagation du virus dans une lignée hépatique humaine, et ce, à 2 étapes de son cycle biologique : l’entrée et la réplication. L’objectif du présent travail était de poursuivre la validation de ces nouvelles cibles thérapeutiques potentielles, en approfondissant nos connaissances sur la dépendance du virus à l’égard de ces kinases au cours de son entrée. Pour cela, nous avons utilisé le modèle des hépatocytes humains primaires, système in vitro plus proche du contexte physiologique que les modèles utilisés jusqu’à présent et qui étaient basés sur l’exploitation de lignées. Deux axes ont été développés : Vérification de l’importance de l’activité kinase des PI4KIIIs au cours de l’entrée du VHC dans les hépatocytes humains primaires, à travers une approche chimique ; Validation de l’implication de ces kinases et de leur activité enzymatique au cours de l’entrée virale grâce à une approche génétique basée sur l’ARN interférence et la restauration de phénotype. En parallèle, nous avons étudié l’expression de PI4KIIIα au cours de pathologies hépatiques. Nos résultats suggèrent une implication de PI4KIIIα au cours de l’entrée du VHC dans les hépatocytes humains primaires, mais restent à confirmer quant à l’implication de PI4KIIIβ. Par ailleurs, l’analyse de l’expression de PI4KIIIα dans le carcinome hépatocellulaire (CHC) conduit à proposer cette kinase comme un nouveau marqueur moléculaire, qui pourrait améliorer les modèles de pronostic déjà établis et pourrait conduire au développement de nouvelles approches thérapeutiques pour les patients atteints d’un CHC, quelque soit l’étiologie.
https://tel.archives-ouvertes.fr/tel-00950335

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2013REN1B006
tel-00950335
https://tel.archives-ouvertes.fr/tel-00950335
https://tel.archives-ouvertes.fr/tel-00950335/document
https://tel.archives-ouvertes.fr/tel-00950335/file/ILBOUDOAdeodat.pdf