Role of Mir-218 Introphoblast Cell Migration, Invasion and Survival, and Its Dysregulation in Preeclampsia.

Abstract

Preeclampsia (PE) is the leading cause of maternal and fetal morbidity and mortality, affecting ~8% of all pregnancies worldwide. The cause of PE is still unclear, however, poor trophoblast migration and invasion into the decidua is believed to play a crucial role. Reports of miRNA regulation in development and disease are increasing. However, the function of microRNA (miR) in placental development and pathology is still poorly understood. In this study, we examined the expression and function of miR-218 in human placentas. Using RNA extracted from placental tissue samples from PE patients and healthy subjects, we measured miR-218 levels by quantitative Real Time–PCR (qRT-PCR). A clear decrease in miR-218 levels was observed in both early- (<34 weeks) and late-onset (= 34 weeks) PE placental tissues, as compared to their gestational age-matched controls. To assess the function of miR218 in trophoblast cells we generated mir-218 overexpressing cells in the HTR8/SVneo stable cell line. Specifically, the mir-218-1 stem-loop sequence was subcloned into the miRNASelect pEGP-miR Cloning and Expression Vector and screened using Puromycin resistance. Putative positive clones were further analyzed by qRT-PCR to assess levels of miR-218 overexpression. Three cell lines were selected for future experiments: GFP (empty vector control), mir-218-low (low level of overexpression) and mir-218-high (high-level of overexpression). Functional studies indicated that the overexpression of miR-218 induced trophoblast cell migration and invasion in HTR8/SVneo cells using wound-healing and matrigel transwell assays, respectively. Furthermore, treatment with miR218 mimics promoted the outgrowth of first trimester placental explants. In addition, growth of these cells under serum-free conditions suggests that miR-218 increases trophoblast survival. Taken together, our data demonstrates that miR218 promotes trophoblast cell migration, invasion and survival. Our findings also suggest that a decrease in placental miR-218 level may contribute to the pathogenesis of preeclampsia.