Sexual Dimorphism in Mitochondrial Metabolism and Insulin Sensitivity Is Controlled by HSP72-ERa Crosstalk

Abstract

HSP72 is highly induced during exercise, and muscle expression is reduced in obese and diabetic men. Muscle-specific HSP72 overexpression protects male mice against diet-induced obesity and insulin resistance. The current study objective was to determine the mechanisms by which HSP72 controls metabolic function and to ascertain whether these mechanisms are impacted by biological sex. We interrogated the impact of biological sex and estradiol action in the context of HSP72 loss and gain of expression in mice. HSP72 is a binding partner of the mitochondrial quality control protein Parkin. HSP72-KO led to metabolic dysfunction via impaired Parkin action, by promoting the retention of enlarged, fission incompetent mitochondria with reduced respiratory capacity. In contrast, female KOs remained lean and insulin sensitive with small spherical muscle mitochondria. Muscle estrogen receptor alpha transcript and protein (Esr1/ERa) was induced in female HSP72-KO vs. wildtype (WT), and this enhanced Parkin-DRP1-induced fatty acid oxidation and underpinned improvements in exercise capacity. The phenotype of female HSP72-KO mice recapitulates that of muscle-specific ESR1 overexpression animals. Because muscle ERa expression was identical between male genotypes, KO vs. WT, we treated male KO mice with 17β-estradiol and the treatment restored mitochondrial form/function as well as insulin sensitivity. In summary, biological sex is critical for understanding the impact of HSP72 in governing metabolic health and insulin sensitivity. National Institutes of Health DK060484 and P30DK063491. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.