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Interspecies NASH disease activity whole-genome profiling identifies a fibrogenic role of PPAR?-regulated dermatopontin.

ABSTRACT: Nonalcoholic fatty liver disease prevalence is soaring with the obesity pandemic, but the pathogenic mechanisms leading to the progression toward active nonalcoholic steatohepatitis (NASH) and fibrosis, major causes of liver-related death, are poorly defined. To identify key components during the progression toward NASH and fibrosis, we investigated the liver transcriptome in a human cohort of NASH patients. The transition from histologically proven fatty liver to NASH and fibrosis was characterized by gene expression patterns that successively reflected altered functions in metabolism, inflammation, and epithelial-mesenchymal transition. A meta-analysis combining our and public human transcriptomic datasets with murine models of NASH and fibrosis defined a molecular signature characterizing NASH and fibrosis and evidencing abnormal inflammation and extracellular matrix (ECM) homeostasis. Dermatopontin expression was found increased in fibrosis, and reversal of fibrosis after gastric bypass correlated with decreased dermatopontin expression. Functional studies in mice identified an active role for dermatopontin in collagen deposition and fibrosis. PPAR? activation lowered dermatopontin expression through a transrepressive mechanism affecting the Klf6/TGF?1 pathway. Liver fibrotic histological damages are thus characterized by the deregulated expression of a restricted set of inflammation- and ECM-related genes. Among them, dermatopontin may be a valuable target to reverse the hepatic fibrotic process.

SUBMITTER: Lefebvre P

PROVIDER: S-EPMC5499370 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

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Interspecies NASH disease activity whole-genome profiling identifies a fibrogenic role of PPARα-regulated dermatopontin.

Lefebvre Philippe P Lalloyer Fanny F Baugé Eric E Pawlak Michal M Gheeraert Céline C Dehondt Hélène H Vanhoutte Jonathan J Woitrain Eloise E Hennuyer Nathalie N Mazuy Claire C Bobowski-Gérard Marie M Zummo Francesco Paolo FP Derudas Bruno B Driessen Ann A Hubens Guy G Vonghia Luisa L Kwanten Wilhelmus J WJ Michielsen Peter P Vanwolleghem Thomas T Eeckhoute Jérôme J Verrijken An A Van Gaal Luc L Francque Sven S Staels Bart B

JCI insight 20170706 13

Nonalcoholic fatty liver disease prevalence is soaring with the obesity pandemic, but the pathogenic mechanisms leading to the progression toward active nonalcoholic steatohepatitis (NASH) and fibrosis, major causes of liver-related death, are poorly defined. To identify key components during the progression toward NASH and fibrosis, we investigated the liver transcriptome in a human cohort of NASH patients. The transition from histologically proven fatty liver to NASH and fibrosis was character ...[more]

PMID: 28679947

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Project description:Nonalcoholic steatohepatitis (NASH) is recognized by hepatic lipid accumulation, inflammation, and fibrosis. No studies have evaluated the prolonged-release pirfenidone (PR-PFD) properties on NASH features. The aim of this study is to evaluate how PR-PFD performs on metabolic functions, and provide insight on a mouse model of human NASH. Male C57BL/6J mice were fed with either normo diet or high-fat/carbohydrate diet for 16 weeks and a subgroup also fed with PR-PFD (300 mg/kg/day). An insulin tolerance test was performed at the end of treatment. Histological analysis, determination of serum hormones, adipocytokines measurement, and evaluation of proteins by western blot was performed. Molecular docking, in silico site-directed mutagenesis, and in vitro experiments using HepG2 cultured cells were performed to validate PR-PFD binding to peroxisome proliferator-activated receptor alpha (PPAR-α), activation of PPAR-α promoter, and sirtuin 1 (SIRT1) protein expression. Compared with the high-fat group, the PR-PFD-treated mice displayed less weight gain, cholesterol, very low density lipoprotein and triglycerides, and showed a significant reduction of hepatic macrosteatosis, inflammation, hepatocyte ballooning, fibrosis, epididymal fat, and total adiposity. PR-PFD restored levels of insulin, glucagon, adiponectin, and resistin along with improved insulin resistance. Noteworthy, SIRT1-liver kinase B1-phospho-5' adenosine monophosphate-activated protein kinase signaling and the PPAR-α/carnitine O-palmitoyltransferase 1/acyl-CoA oxidase 1 pathway were clearly induced in high fat + PR-PFD mice. In HepG2 cells incubated with palmitate, PR-PFD induced activation and nuclear translocation of both PPARα and SIRT1, which correlated with increased SIRT1 phosphorylated in serine 47, suggesting a positive feedback loop between the two proteins. These results were confirmed with both synthetic PPAR-α and SIRT1 activators and inhibitors. Finally, we found that PR-PFD is a true agonist/ligand for PPAR-α. Conclusions: PR-PFD provided an anti-steatogenic effect and protection for inflammation and fibrosis.

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Dataset Information

Interspecies NASH disease activity whole-genome profiling identifies a fibrogenic role of PPAR?-regulated dermatopontin.

Publications

Interspecies NASH disease activity whole-genome profiling identifies a fibrogenic role of PPARα-regulated dermatopontin.

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