MCRS1 is a histone acetylation regulator whose loss in hepatocytes promotes cirrhosis

ABSTRACT: Cirrhosis is a late stage of fibrosis that fatally impairs liver function. Unfortunately, genetic animal models mimicking human cirrhosis are lacking and the molecular mechanisms remain unknown. Here we report the first murine genetic model recapitulating clinical features of cirrhosis, which are induced by hepatocyte-specific elimination of microspherule protein 1 (MCRS1), a member of the non-specific lethal (NSL) and INO80 chromatin modifier complexes. Deregulation of bile acid (BA) transporter expression, revealed by proteomic analysis of MCRS1-depleted mouse livers, with pronounced downregulation of the Na+-taurocholate cotransporting polypeptide (NTCP), causes BA accumulation in liver sinusoids. Genetic ablation of the BA receptor FXR in hepatic stellate cells (HSCs) suppresses bile duct ligation (BDL)-induced fibrosis in mice. Moreover, in vitro experiments demonstrate that fibrotic marker expression is reduced in FXR-depleted HSCs cultured in conditioned medium containing high BAs from MCRS1-depleted hepatocytes. Additionally, hepatocytic MCRS1 overexpression increases their NTCP levels, and consequently protects mice against BDL-induced liver fibrosis. Deletion of a putative SANT domain in MCRS1, also revealed by protein sequence analysis and essential for histone H3 (H3) binding, disrupts H3/HDAC1 complex formation. This evicts MCRS1 and HDAC1 from their H3 anchoring sites and increases histone lysine acetylation of BA transporter genes, independently of the NSL or INO80 complexes. Taken together, our data reveal a previously unrecognized function of MCRS1 as a novel histone acetylation regulator that binds to H3, and recruits a novel chromatin-modifying complex that maintains gene expression homeostasis and liver health. Accordingly, loss of nuclear MCRS1 correlates with increased histone acetylation in human cirrhosis samples. Regulation of histone acetylation might thus be central to cirrhotic development.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Liver

SUBMITTER: Eduardo Zarzuela  

LAB HEAD: Javier Muñoz

PROVIDER: PXD023026 | Pride | 2022-05-19

REPOSITORIES: Pride