A Somatic Mutation in HIF-2α Affects Glucose and Lipid Metabolism via CD36 and Ceramide.

Hypoxia-inducible factor 2α (HIF-2α) plays a critical role in metabolic regulation. Previously, our team identified a novel mutation (c.C2473T, p.R825W) within the C-terminal transactivation domain of HIF-2α, which was associated with the pathogenesis of non-alcoholic fatty liver disease. The present study aimed to investigate the relationship between this mutation and disorders of glucose and lipid metabolism, and to elucidate the underlying mechanisms. A HIF-2α mutant C56BL/6 mouse model and THLE-2 and HEK293 cell lines carrying the same mutation were established. Co-immunoprecipitation and western blot were used to assess the molecular effects of the mutation. Transcriptome sequencing, quantitative real-time PCR, and western blotting were performed to identify differentially expressed genes, while lipidomics was applied to evaluate ceramide profiles in mutant and control mice. Herein, we found that HIF-2α mutant mice exhibited impaired glucose tolerance and enhanced transactivation activity of the mutant protein. The AMP-activated protein kinase (AMPK) pathway was significantly upregulated in mutant models. Notably, Cd36, a gene in this pathway, showed increased expression in both mutant mice and cell lines. Ceramide levels were elevated in the mutant group, and positively correlated with hepatic triglyceride accumulation. Inhibition of ceramide synthesis decreased the expression of genes involved in gluconeogenesis and fatty acid transport and reduced hepatic lipid droplet formation in mutant mice. Collectively, these findings indicate that the HIF-2α mutation enhances Cd36 expression by increased transactivation activity, thereby elevating ceramide level and disrupting glucose and lipid homeostasis. This study provides a theoretical basis for precise treatment of metabolic disorders.