An estrogen receptor α-derived peptide improves glucose homeostasis during obesity

Estrogen improves insulin sensitivity and increases energy expenditure, contributing to sexual dimorphism regarding type 2 diabetes mellitus (T2DM) susceptibility. Estrogen receptor α (ERα) plays a crucial role in mediating estrogen action on glucose and energy homeostasis. However, the underlying mechanisms remain incompletely understood. Here, we found a ligand-independent effect of ERα on the regulation of glucose homeostasis and identified an ERα-derived peptide as a potential insulin sensitizer. Deficiency of ERα but not ERβ in the liver impaired glucose homeostasis in male, female, and ovariectomized (OVX) female mice. Mechanistic studies revealed that ERα promoted hepatic insulin sensitivity by suppressing ubiquitination-induced IRS1 degradation. The ERα 1-280 domain mediated the ligand-independent effect of ERα on insulin sensitivity. Furthermore, we designed a peptide based on ERα 1-280 domain and found that ERα-derived peptide interacted with IRS1, increased IRS1 stability through suppressing its ubiquitination, and enhanced insulin sensitivity. Importantly, administration of ERα-derived peptide into obese mice significantly increased insulin sensitivity, attenuated glucose intolerance, and improved serum lipid profiles. These findings pave the way for the therapeutic intervention of T2DM by targeting the ligand-independent effect of ERα and indicate that ERα-derived peptide is a potential insulin sensitizer for the treatment of T2DM.