LIM domain only 7 negatively controls nonalcoholic steatohepatitis in the setting of hyperlipidemia

Abstract

Background and Aims: Hyperlipidemia has been extensively recognized as a high-risk factor for NASH; however, clinical susceptibility to NASH is highly heterogeneous. The key controller(s) of NASH susceptibility in patients with hyperlipidemia has not yet been elucidated. Here, we aimed to reveal the key regulators of NASH in patients with hyperlipidemia and to explore its role and underlying mechanisms. Approach and Results: To identify the predominant suppressors of NASH in the setting of hyperlipidemia, we collected liver biopsy samples from patients with hyperlipidemia, with or without NASH, and performed RNA-sequencing analysis. Notably, decreased Lineage specific Interacting Motif domain only 7 (LMO7) expression robustly correlated with the occurrence and severity of NASH. Although overexpression of LMO7 effectively blocked hepatic lipid accumulation and inflammation, LMO7 deficiency in hepatocytes greatly exacerbated diet–induced NASH progression. Mechanistically, lysine 48 (K48)-linked ubiquitin-mediated proteasomal degradation of tripartite motif-containing 47 (TRIM47) and subsequent inactivation of the c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK) cascade are required for the protective function of LMO7 in NASH. Conclusions: These findings provide proof-of-concept evidence supporting LMO7 as a robust suppressor of NASH in the context of hyperlipidemia, indicating that targeting the LMO7-TRIM47 axis is a promising therapeutic strategy for NASH.