Neuregulin 4 suppresses NASH-associated liver cancer through restraining tumor-prone liver microenvironment

The mammalian liver comprises heterogeneous cell types within its tissue microenvironment that respond to physiological cues and undergo pathophysiological reprogramming in disease states, such as nonalcoholic steatohepatitis (NASH). Patients with NASH are at increased risk for the development of hepatocellular carcinoma (HCC). However, the molecular and cellular nature of liver microenvironment remodeling that links NASH to liver carcinogenesis remains obscure. Here we show that diet-induced NASH is characterized by induction of tumor-associated macrophage (TAM)-like macrophages and exhaustion of cytotoxic T cells in mouse liver. The adipose-derived endocrine factor Neuregulin 4 (NRG4) serves as a hormonal checkpoint that restrains this pathological reprogramming during NASH. NRG4 deficiency exacerbates the induction of tumor-prone liver immune microenvironment and NASH-associated HCC, whereas transgenic NRG4 overexpression elicits protective effects in mice. In a therapeutic setting, recombinant NRG4 protein exhibits remarkable efficacy in inhibiting HCC in mice with NASH, thereby paving the way for future therapeutic development. Overall design: RNA-seq on nonalcoholic steatohepatitis (NASH) mouse liver in different genotypes; Single cell RNA-seq on non-parenchymal cells of NASH mouse liver.