Vitronectin stimulates hepatic gluconeogenesis by activating the cAMP/PKA/CREB axis in the liver

Abstract

Vitronectin, a protein derived the human placenta, has been identified as an inducer of insulin resistance in trophoblast cells in gestational diabetes mellitus (GDM). As a secreted protein, vitronectin may have systemic effects on dysregulated glucose metabolism in GDM. To address this speculation, we generated a GDM mouse model using high-fat diet-induced obese mice. Consistent with findings in placentas of GDM patients, GDM mouse placentas showed higher vitronectin expression, accompanied by increased serum vitronectin levels. Reduced insulin signaling transduction was observed in both the placentas and livers of GDM mice, along with enhanced hepatic gluconeogenesis. To further explore the role of vitronectin in hepatic gluconeogenesis, we constructed an adeno-associated virus expressing Vtn (AAV-VTN), which was administered to mice via tail vein injection. In AAV-VTN-treated mice, glucose production from exogenous pyruvate increased, and the expression of gluconeogenic genes in the liver was upregulated, indicating that hepatic gluconeogenesis was stimulated by vitronectin. Mechanistically, vitronectin binds to its receptor CD51/61, activating the cAMP/PKA/CREB axis in hepatocytes, thereby promoting hepatic gluconeogenesis. In summary, our findings suggest that placenta-derived vitronectin plays a critical role in inducing insulin resistance in the liver in GDM. Moreover, vitronectin stimulates hepatic gluconeogenesis through activation of the cAMP/PKA/CREB axis. These results point to vitronectin as a potential therapeutic target for managing hyperglycemia in GDM.