1. Alcohol directly stimulates epigenetic modifications in hepatic stellate cells
- Author
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Agata Page, Jelena Mann, Stephen J. Hill, Soo-Mi Kweon, Raymond Wu, Jeremy French, Rachel Howarth, Derek A. Mann, Steve White, Hidekazu Tsukamoto, and Pier P. Paoli
- Subjects
Male ,Immunoblotting ,Biology ,Polymerase Chain Reaction ,Article ,Epigenesis, Genetic ,Rats, Sprague-Dawley ,Mice ,Liver Cirrhosis, Alcoholic ,Hepatic Stellate Cells ,Animals ,Humans ,Epigenetics ,Cells, Cultured ,Regulation of gene expression ,Extracellular Matrix Proteins ,Ethanol ,Hepatology ,Transdifferentiation ,DNA ,Epigenome ,Immunohistochemistry ,Rats ,Chromatin ,Cell biology ,Disease Models, Animal ,Gene Expression Regulation ,Biochemistry ,Cell Transdifferentiation ,Disease Progression ,Hepatic stellate cell ,Chromatin immunoprecipitation - Abstract
Background & Aims Alcohol is a primary cause of liver disease and an important co-morbidity factor in other causes of liver disease. A common feature of progressive liver disease is fibrosis, which results from the net deposition of fibril-forming extracellular matrix (ECM). The hepatic stellate cell (HSC) is widely considered to be the major cellular source of fibrotic ECM. We determined if HSCs are responsive to direct stimulation by alcohol. Methods HSCs undergoing transdifferentiation were incubated with ethanol and expression of fibrogenic genes and epigenetic regulators was measured. Mechanisms responsible for recorded changes were investigated using ChIP-Seq and bioinformatics analysis. Ethanol induced changes were confirmed using HSCs isolated from a mouse alcohol model and from ALD patient's liver and through precision cut liver slices. Results HSCs responded to ethanol exposure by increasing profibrogenic and ECM gene expression including elastin. Ethanol induced an altered expression of multiple epigenetic regulators, indicative of a potential to modulate chromatin structure during HSC transdifferentiation. MLL1, a histone 3 lysine 4 (H3K4) methyltransferase, was induced by ethanol and recruited to the elastin gene promoter where it was associated with enriched H3K4me3, a mark of active chromatin. Chromatin immunoprecipitation sequencing (ChIPseq) revealed that ethanol has broad effects on the HSC epigenome and identified 41 gene loci at which both MML1 and its H3K4me3 mark were enriched in response to ethanol. Conclusions Ethanol directly influences HSC transdifferentiation by stimulating global changes in chromatin structure, resulting in the increased expression of ECM proteins. The ability of alcohol to remodel the epigenome during HSC transdifferentiation provides mechanisms for it to act as a co-morbidity factor in liver disease.
- Published
- 2015