LncRNA Gm35585 transcriptionally activates the peroxidase EHHADH against diet-induced fatty liver

Metabolic-dysfunction-associated steatotic liver disease is one of the most common chronic liver diseases worldwide and has no approved treatment thus far. Here we report that the hepatic overexpression of Gm35585, a novel lncRNA downregulated in the livers of mice fed a high-fat diet, is functionally important in alleviating hepatic lipid accumulation pathologies. Gm35585 activates the peroxisome proliferator-activated receptor α (PPARα) signaling pathway and promotes the expression of downstream PPARα-target gene, enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH), which is one of the four enzymes of the peroxisomal β-oxidation pathway. Activation of EHHADH promotes the oxidation of long-chain fatty acids (LCFAs), and the increased levels of hepatic LCFAs contribute to metabolic-dysfunction-associated steatotic liver disease. Mechanistically, Gm35585 binds to retinoid X receptor α (RXRα) and then forms a PPARα/RXRα heterodimer with PPARα and guides the heterodimer to recognize the promoter of EHHADH, which is called peroxisome proliferator-activated receptor response element, causing transcriptional activation of EHHADH. Taken together, Gm35585 is a hepatic lipid metabolism regulator that activates EHHADH transcription, promoting peroxisomal β-oxidation of LCFAs and ultimately ameliorating diet-induced fatty liver.