Activation of hepatic adenosine A1 receptor ameliorates MASH via inhibiting SREBPs maturation

Abstract

Metabolic (dysfunction)-associated steatohepatitis (MASH) is the advanced stage of metabolic (dysfunction)-associated fatty liver disease (MAFLD) lacking approved clinical drugs. Adenosine A1 receptor (A₁R), belonging to the G-protein-coupled receptors (GPCRs) superfamily, is mainly distributed in the central nervous system and major peripheral organs with wide-ranging physiological functions; however, the exact role of hepatic A₁R in MAFLD remains unclear. Here, we report that liver-specific depletion of A₁R aggravates while overexpression attenuates diet-induced metabolic-associated fatty liver (MAFL)/MASH in mice. Mechanistically, activation of hepatic A₁R promotes the competitive binding of sterol-regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) to sequestosome 1 (SQSTM1), rather than protein kinase A (PKA) leading to SCAP degradation in lysosomes. Reduced SCAP hinders SREBP1c/2 maturation and thus suppresses de novo lipogenesis and inflammation. Higher hepatic A₁R expression is observed in patients with MAFL/MASH and high-fat diet (HFD)-fed mice, which is supposed to be a physiologically adaptive response because A₁R agonists attenuate MAFL/MASH in an A₁R-dependent manner. These results highlight that hepatic A₁R is a potential target for MAFL/MASH therapy.

Keywords: MASH; SCAP-SREBPs pathway; adenosine A1 receptor; de novo lipogenesis; inflammation.