FoxO1 in Embryonic Heart: Its Regulation by mTOR and Its Alteration by Maternal Diabetes

GATTI CINTIA R; HIGA ROMINA; ROBERTI SABRINA L; SATO HUGO; JAWERBAUM ALICIA

MODO VIRTUAL

Congreso; LATIN AMERICAN DOHaD 2020. One World One Health. On the Web.; 2020

The transcription factor FoxO1 has a role in heart development by being involved in the metabolism, oxidative stress, endothelial dysfunction, inflammation and apoptosis of the cardiomyocyte. It phosphorylation in Ser 256 induces its nuclear exclusion and inactivation and this mechanism can be modulated by mechanistic target of rapamycin (mTOR). Maternal diabetes affects the embryonic, fetal and perinatal development and programs metabolic and cardiovascular alterations in the adult offspring. We have recently reported cardiovascular alterations related to the FoxO1 pathway in the adult offspring from diabetic rats.Angiopoietin-2 is an endothelial secreted factor involved in vascular development and inflammatory processes.We aim to evaluate the in vitro regulation of FoxO1 phosphorylation by mTOR in the heart of the embryo and the in vivo expression of angiopoietin-2, a FoxO1 target gene, in the heart of the embryo and offspring from diabetic rats.MethodsHeart explants obtained from embryos of control rats at day 12 of pregnancy were incubated with a mTOR inhibitor (Torin, 1µM) during 3 hours and phosphorylation of ribosomal protein S6 (Ser-235/236) and FoxO1 (Ser-473) was measured by Western Blot. The experimental model of diabetes was obtained by streptozotocin administration to adult rats (50mg/kg). Control and diabetic rats were euthanized at day 12 of pregnancy, embryonic hearts were collected and stored for P-FoxO1 and total FoxO1 measurement by Western blot and expression of angiopoietin-2 by qPCR assays. In the adult male offspring from diabetic rats, heart was obtained for measurements of the mRNA expression of angiopoietin-2 by qPCR assays. ResultsThe mTOR inhibitor Torin decreased P-rpS6 (mTORC1 downstream target) (74%, p