Transcriptional regulation of Hepatic Stellate Cell activation in NASH

Ann-Britt Marcher,Sönke Detlefsen,Sonja S Hohmann,Sofie M Bendixen,Susanne Mandrup,Kim Ravnskjaer,Bjørk D Larsen,Maria H Hansen,Henrik Dimke,Mike K Terkelsen

doi:10.1038/s41598-019-39112-6

Ann-Britt Marcher, Sönke Detlefsen + Show 8 more

Open Access

https://doi.org/10.1038/s41598-019-39112-6

Copy DOI

Abstract

Non-alcoholic steatohepatitis (NASH) signified by hepatic steatosis, inflammation, hepatocellular injury, and fibrosis is a growing cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma. Hepatic fibrosis resulting from accumulation of extracellular matrix proteins secreted by hepatic myofibroblasts plays an important role in disease progression. Activated hepatic stellate cells (HSCs) have been identified as the primary source of myofibroblasts in animal models of hepatotoxic liver injury; however, so far HSC activation and plasticity have not been thoroughly investigated in the context of NASH-related fibrogenesis. Here we have determined the time-resolved changes in the HSC transcriptome during development of Western diet- and fructose-induced NASH in mice, a NASH model recapitulating human disease. Intriguingly, HSC transcriptional dynamics are highly similar across disease models pointing to HSC activation as a point of convergence in the development of fibrotic liver disease. Bioinformatic interrogation of the promoter sequences of activated genes combined with loss-of-function experiments indicates that the transcriptional regulators ETS1 and RUNX1 act as drivers of NASH-associated HSC plasticity. Taken together, our results implicate HSC activation and transcriptional plasticity as key aspects of NASH pathophysiology.

Highlights

Fate-tracing experiments in mice have identified activated hepatic stellate cells (HSCs) as precursors for ECM-producing myofibroblasts in mice treated with carbon tetrachloride (CCl4), fed a methionine/ choline-deficient (MCD) diet, or subjected to bile duct ligation[10]
We have demonstrated that ETS1 and RUNX1 motifs are strongly enriched in promoters of the induced genes in cluster 6 and highly predictive of Non-alcoholic steatohepatitis (NASH)-associated gene induction in HSCs
Despite etiological and histopathological differences between with g/L D-fructose (WD)-fed and CCl4-treated mice, we find transcriptional programs underlying HSC activation and fibrogenesis being remarkably similar across disease models

Summary

Introduction

Fate-tracing experiments in mice have identified activated hepatic stellate cells (HSCs) as precursors for ECM-producing myofibroblasts in mice treated with carbon tetrachloride (CCl4), fed a methionine/ choline-deficient (MCD) diet, or subjected to bile duct ligation[10]. While it is recognized that activation and transdifferentiation of quiescent HSCs to myofibroblasts involves profound changes in gene expression, little is known about the transcriptional effectors of the above signals. Several studies comparing global gene expression in quiescent and activated HSCs have been published in recent years[26,27,28,29,30,31,32]. An increasing number of studies include global analyses of hepatic gene expression in NAFLD and NASH33–36, none of these offer the cell type resolution to address NASH-associated HSC plasticity or the transcriptional basis for HSC activation. By time-resolved gene expression profiling of isolated HSCs we here determine the transcriptional programs that define early HSC activation in diet-induced NASH in mice. We show that acute loss of ETS1 and RUNX1 function attenuates HSC activation

Methods

Results

Conclusion