BCAM Deficiency May Contribute to Preeclampsia by Suppressing the PIK3R6/p-STAT3 Signaling.

Abstract

Preeclampsia is a pregnancy syndrome that may utilize multiple pathogenic mechanisms. Insufficient trophoblast invasion and impaired uterine spiral artery remodeling are believed to be the pathological basis; yet the underlying mechanisms remain largely unclear. The placental BCAM (basal cell adhesion molecule) expression and important clinical indicators were detected and correlation analysis was performed. MiRNAs directly targeting BCAM were predicted and further verified by dual-luciferase reporter gene, and the downstream molecular mechanisms of BCAM were investigated in both HTR-8/SVneo and JAR cells. In addition, pregnant/nonpregnant rats were treated with adenoviruses containing BCAM shRNA genes (Ad-shBCAM) on gestational 9.5 days to detect the preeclamptic features. The BCAM is highly expressed on the trophoblast membrane and decreased in the preeclamptic placentae. In HTR-8/SVneo and JAR cells, BCAM knockdown inhibited trophoblast proliferation, migration, and invasion, and suppressed phosphorylation on Y705 of STAT3 dependent on the downregulation of PIK3R6. Moreover, miR-199a-5p mediated the degradation of BCAM and also inhibited trophoblast proliferation, migration, and invasion. In vivo, BCAM deficiency induced a preeclampsia-like phenotype included elevated systolic blood pressure, proteinuria, impaired morphology and function of multiple organs (placenta, liver, and kidney), and fetal growth restriction. The expression of placenta BCAM/PIK3R6/p-STAT3 signaling was also downregulated in this preeclampsia rat model. MiR-199a-5p mediated-BCAM deficiency contributes to the suppression of trophoblast proliferation, migration, and invasion by inhibiting PIK3R6/p-STAT3 signaling, which may lead to poor placentation and result in preeclampsia-like phenotypes. Our study provides a new academic perspective on the pathogenesis of preeclampsia.