EFFECT OF OXIDATIVE STRESS ON AUTOPHAGY IN PLACENTAL TISSUE

Abstract

Preeclampsia (PE) is a human pregnancy-specific syndrome, which is characterized by endothelial damage and severe systemic inflammatory response. The development of this disease is due to immune-poor adaptation in maternal-fetal interface, determining low uteroplacental blood flow that results in placental hypoxia/ischemia, oxidative stress and fetal growth restriction. Oxidative stress resulting of injury from placental hypoxia and reperfusion induces an inflammatory response with increased production of mediators of dysfunction of endothelial cells and pro-inflammatory cytokines. Thus, in PE, placenta expresses intense oxidative stress resulting from injury caused by hypoxia and ischemia and/or deficiency of antioxidant defenses. Autophagy is an intracellular catabolic process that eliminates damaged organelles and proteins at cytoplasm and it appears to be a potent anti-inflammatory mechanism, able to maintain cellular homeostasis. Defects in this process may contribute to the development of range human diseases, including inflammatory diseases. Autophagy can control inflammation from regulating inflammasome activation, an important intracellular complex for the processing and release of proinflammatory cytokines. This project aims to assess whether the treatment of placental explants with hydrogen peroxide (H2O2) induces autophagy and activate the inflammasome in placenta from normotensive pregnant women in the third trimester of pregnancy. Therefore, placental explants obtained from normotensive pregnant women undergoing elective cesarean section (n = 15) will be cultivated with different concentrations of H2O2 for 4 h and 24 h. After 4h oxidative stress will be assessed by markers superoxide dismutase and catalase in the supernatant of cultures. The gene expression of autophagy markers (LC3-II beclin-1 and p62) and cytokines IL-1², IL-10 and TNF-± and inflammasome (NLRP3 and Caspase-1) will be evaluated by RT-qPCR. After 24 hours of culture, the supernatant will be used for the determination of human chorionic gonadotropin (hCG), heat shock protein Hsp70 and cytokines IL-1², IL-10 and TNF-± by enzyme immunoassay.