INHBE is upregulated in MASLD and MASLD-related HCC and promotes lipid accumulation and malignant phenotypes in vitro

Background and aims Metabolic dysfunction-associated steatotic liver disease (MASLD) is currently the most prevalent chronic liver disease globally and has recently emerged as the fastest-rising cause of hepatocellular carcinoma (HCC) in many countries. Inhibin beta E (INHBE) has also been implicated as a potential player in metabolic disorders, but its role in MASLD and MASLD-related HCC remains largely unexplored. Therefore, this study aimed to investigate the expression and functional role of INHBE in MASLD and MASLD-related HCC. Methods Transcriptomic data from three independent MASLD cohorts (GSE135251, GSE130970, and GSE193084) were analyzed to evaluate INHBE expression and its correlation with nonalcoholic fatty liver disease activity score (NAS) and disease-related gene signatures. An oleic acid and palmitic acid-induced steatosis model in THLE-2 cells was established to investigate the effect of INHBE knockdown on lipid metabolism, inflammation, and fibrosis using quantitative real-time polymerase chain reaction, Oil Red O staining, and triglyceride quantification. Additional assays were conducted in Huh7 cells to assess the effect of INHBE on cell proliferation, migration, and invasion in a MASLD-related HCC context. Mechanistic interrogation included determination of suppressor of mothers against decapentaplegic (SMAD) 3 phosphorylation by Western blot and rescue approaches: supplementation with recombinant human INHBE and pharmacologic activation of SMAD signaling using recombinant transforming growth factor-beta (TGF-β)1. Results INHBE expression was significantly upregulated in MASLD liver tissues and positively correlated with NAS and key genes related to lipid metabolism, inflammation, and fibrosis. Knockdown of INHBE in steatotic THLE-2 cells reduced lipid accumulation, suppressed lipogenic gene expression, and alleviated inflammatory and fibrotic responses. In MASLD-related HCC models, INHBE expression was elevated in both tumor tissues and lipid-loaded HCC cell lines. Knocking down INHBE in lipid-induced Huh7 cells significantly impaired cell proliferation, migration, and invasion. INHBE silencing also led to a marked reduction in SMAD3 phosphorylation without changing total SMAD3 levels. Exogenous recombinant INHBE partially restored lipid accumulation in knockdown THLE-2 cells, and pharmacologic activation of SMAD signaling with TGF-β partially rescued the proliferation and migration deficits observed in INHBE-silenced, lipid-loaded Huh7 cells. Conclusions INHBE is upregulated in MASLD and MASLD-related HCC and contributes to disease progression by promoting hepatic steatosis, inflammation, fibrosis, and tumor aggressiveness. Targeting INHBE warrants further investigation as a potential therapeutic strategy for MASLD and its progression to HCC.