LncRNA-Snhg3Aggravates Hepatic Steatosis by Regulating PPARγ via SND1/H3K27me3

AbstractLncRNAs are involved in modulating the individual risk and the severity of progression in metabolic dysfunction-associated fatty liver disease (MASLD), but their precise roles remain largely unknown. This study aimed to investigate the role of lncRNASnhg3in the development and progression of MASLD, along with the underlying mechanisms.In vitroandin vivoexperiments revealed thatSnhg3is involved in lipid metabolism and steatosis. The result showed thatSnhg3was significantly downregulated in the liver of high-fat-induced obesity (DIO) mice. Notably, palmitic acid promoted the expression ofSnhg3and overexpression ofSnhg3increased lipid accumulation in primary hepatocytes. Furthermore, knock-in and knock-out models showed significant changes in body and liver weight, heat production, total oxygen consumption, and carbon dioxide production. Hepatocyte-specificSnhg3deficiency alleviated hepatic steatosis in DIO mice, whereas overexpression induced the opposite effect. Mechanistically,Snhg3promoted the expression, stability and nuclear localization of SND1 protein via interacting with SND1, thereby inducing K63-linked ubiquitination modification of SND1. Moreover,Snhg3decreased the H3K27me3 level and induced SND1-mediated chromatin loose remodeling, thus reducing H3K27me3 enrichment at thePparγpromoter and enhancingPparγexpression. In addition, the administration of PPARγ inhibitor T0070907 improvedSnhg3-aggravated hepatic steatosis. Our study revealed a new signaling pathway,Snhg3/SND1/H3K27me3/PPARγ, responsible for MASLD and indicates that lncRNA-mediated epigenetic modification has a crucial role in the pathology of MASLD.