CIDEB and CGI-58 differentially regulate liver lipid-droplet cholesterol to modulate metabolic dysfunction-associated steatohepatitis severity.

Metabolic dysfunction-associated steatohepatitis (MASH) increases liver-related mortality, and new therapies targeting its underlying mechanisms are warranted. We examined whether two lipid-droplet proteins, CIDEB and CGI-58, exert opposing control over MASH by altering cholesterol in liver lipid droplets. Using antisense oligonucleotides, we silenced CIDEB or CGI-58 in the livers of C57BL/6J mice fed a choline-deficient, L-amino acid-defined high-fat diet. CIDEB silencing decreased both triglyceride and cholesterol levels in liver lipid droplets and lowered plasma transaminases and the number of crown-like structures. These protective effects were abrogated by cholesterol supplementation. Conversely, CGI-58 knockdown raised triglyceride and cholesterol levels and exacerbated MASH; bempedoic acid, a cholesterol-synthesis inhibitor, reversed these changes. Dual CIDEB/CGI-58 silencing confirmed that CGI-58 loss abrogated the protective effects of CIDEB knockdown. Our data establish liver lipid-droplet cholesterol as a critical determinant in MASH mediated by CIDEB and CGI-58 and demonstrate that CIDEB knockdown confers protection by enhancing CGI-58-dependent lipolysis.