Chymotrypsin Enhances Soluble Fms-Like Tyrosine Kinase 1 Production Through Protease-Activated Receptor 2 in Placenta-Derived Immortalized Human Trophoblast Cells

The antithrombin binding regions of heparin mediate fetal growth and reduced placental damage in the RUPP model of preeclampsia†

Preeclampsia is a serious hypertensive disorder of pregnancy, which is only cured with delivery of the placenta, thereby commonly necessitating preterm birth of the fetus. Low-molecular-weight heparin (LMWH) has demonstrated potential to reduce the incidence of preeclampsia in high-risk pregnant women, although the underlying mechanism by which LMWH protects against preeclampsia is unknown. Given the complex structure and biologic actions of heparin, we tested the hypothesis that heparin can mediate preeclampsia prevention via nonanticoagulant pathways. We compared the effects of a nonanticoagulant, glycol-split LMWH (gsHep)—rendered nonanticoagulant through disruption of the antithrombin binding regions—with the LMWH dalteparin in the rat reduced uterine perfusion pressure (RUPP) surgical model of preeclampsia. Although RUPP animals exhibit significantly elevated blood pressure and reduced plasma levels of placental growth factor (PGF) compared to sham, neither dalteparin nor gsHep treatment significantly impacted these parameters. However, the observed positive correlation between PGF levels and number of viable fetuses in RUPP-induced animals suggests that reduced PGF levels were predominately due to placental loss. Daily subcutaneous injections of low-dose dalteparin but not gsHep significantly restored fetal growth that was impaired by RUPP surgery. Placentas from RUPP animals exhibited an abnormal labyrinth structure, characterized by expanded sinusoidal blood spaces, relative to sham-operated animals. Morphometric analysis demonstrated that dalteparin but not gsHep treatment normalized development of the labyrinth in RUPP-exposed conceptuses. These data suggest that the antithrombin-binding regions of LMWH are required to confer its protective effects on fetal growth and placental development.

YAP Is Decreased in Preeclampsia and Regulates Invasion and Apoptosis of HTR-8/SVneo

Preeclampsia (PE) is a gestational disorder with hypertension and proteinuria leading to maternal and fetal morbidity and mortality. Yes-associated protein (YAP), a transcription coactivator of Hippo pathway, was identified as an oncoprotein participated in tumorigenesis. However, the effect of YAP on trophoblast has not been investigated. In our study, YAP expression levels in first-trimester, full-term, and PE placentas were detected using quantitative real-time polymerase chain reaction (PCR), Western blot assays, and immunohistochemistry. Yes-associated protein expression was also detected in BeWo and HTR-8/SVneo. Overexpression plasmid and YAP small interfering RNA were introduced into trophoblast cells. Furthermore, we utilized a Transwell invasion assay, flow cytometry, and Cell Counting Kit-8 analysis to examine the role of YAP in the invasion, apoptosis, and proliferation of HTR-8/SVneo trophoblast cells. The result showed that both YAP messenger RNA (mRNA) and protein expression levels were less in preeclamptic placentas. Yes-associated protein mRNA and protein expression levels were more highly expressed in BeWo. Yes-associated protein enhanced cell invasion, reduced the cellular apoptotic response, and had no effect on proliferation. In addition, the overexpression of YAP activated the expression of caudal-related homeobox transcription factor 2 (CDX2), whereas reduced expression of YAP inhibited the expression of CDX2. Our results demonstrate that decreased YAP levels may contribute to the development of PE by regulating trophoblast invasion and apoptosis involving regulation of CDX2. Collectively, we proposed decreased YAP may contribute to trophoblast dysfunction, which suggests it might represent a prognostic biomarker and therapeutic target for PE.