Relaxin confers cytotrophoblast protection from hypoxia-reoxygenation injury through the phosphatidylinositol 3-kinase-Akt/protein kinase B cell survival pathway

Preeclampsia is a hypertensive syndrome that manifests after 20 wk of gestation. Contemporary understanding of the maternal-fetal interface in preeclampsia suggests a major role for placental oxidative stress resulting from ischemia-reperfusion injury. We hypothesized that the pregnancy hormone relaxin would reduce cytotrophoblast apoptosis and necrosis (aponecrosis) and, hence, the export of placental debris into the maternal circulation. If so, then relaxin might be employed as a therapeutic intervention to diminish the activation of the maternal systemic inflammatory response central to the development of clinical disease. HTR-8/SVneo cells, a model for first trimester extravillous trophoblast, were subjected to serum deprivation and hypoxia or hypoxia-reoxygenation. The cells were treated with recombinant human relaxin or vehicle and apoptosis and/or necrosis evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), CellEvent Caspase-3/7 and SYTOX AADvanced kit, and propidium iodide staining as determined by fluorescence microscopy or flow cytometry. To interrogate mechanisms of relaxin cytoprotection, HTR-8/SVneo cells were pretreated with pharmacological inhibitors of PI3-kinase LY294004, Akt/PKB MK-2206, or DMSO vehicle. HTR-8/SVneo cell identity was first confirmed by RT-PCR. The cells expressed placental alkaline phosphatase, aromatase, and human leukocyte antigen G. In addition, the cells expressed the relaxin receptor RXFP1 as well...
Source: AJP: Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Tags: Research Article Source Type: research