“Activated leptin, insulin receptor and translation signaling in placenta from pregnant women with gestational diabetes mellitus

ANTONIO PÉREZ-PÉREZ; FLORA SANCHEZ-GIMENEZ; JULIETA MAYMÓ; YÉSICA GAMBINO; CECILIA VARONE; VICTOR SÁNCHEZ MARGALET

Sevilla

Congreso; • XXXV Congreso de la Sociedad española de Bioquímica y Biología Molecular; 2012

SEBBM

Gestational diabetes patients have high plasma levels of insulin and leptin. Placentas from gestational diabetes suffer from structural and functional changes including overgrowth. We have recently found that leptin stimulates protein synthesis in placenta, in a similar way to insulin, by activating protein signaling machinery. We aimed to study the expression of leptin and leptin receptor (LEPR), as well as LEPR and insulin receptor (IR) activation. Thus, we investigated the phosphorylation of downstream proteins of both the LEPR and IR, including the initiation of translation signaling. We also checked the protein synthesis rate. We have studied ten control placentas and ten placentas from patients with GDM. Leptin and LEPR expression were determined by quantitative real time-PCR and immunoblot. Protein phosphorylation was measured by specific immunoblot. The rate of protein synthesis was assessed by [3H] leucine incorporation experiments. We have found that leptin and LEPR expression are increased in placentas from GDM, and both LEPR and IR are activated as well as the signaling from both receptors in placentas from GDM compared with placentas controls. Finally, the translation machinery activity and protein synthesis rate were also higher in placentas from GDM. In conclusion, we have found for the first time the activation of leptin and insulin receptors in placenta from GDM and this activity may contribute to the increased protein synthesis rate that we have found. Nevertheless, the specific contribution of each receptor in the increased protein synthesis rate remains to be investigated.