The Roles of microRNA in Preeclampsia Induced Fetal Sex-Specific Endothelial Dysfunction

Introduction: Preeclampsia (PE) is a hypertensive disorder that complicates 5-10% of human pregnancies and leads to high fetal morbidity and mortality. Maternal obesity increases the risks of PE by 3-fold in association with elevated circulating pro-inflammatory cytokines which are related to endothelial dysfunction observed in PE. MiR146a-5p is a cardiovascular disease-associated miRNA that regulates endothelial cell responses. We have previously reported fetal sex-specific fetal endothelial dysfunction in PE. Although miR146a-5p has been reported to be dysregulated in PE HUVECs, the role of miR146a-5p in PE-dysregulated fetal sex-specific endothelial dysfunction is unclear. Hypothesis: MiR146a-5p differently mediate PE-induced sex-specific fetal endothelial dysfunction in lean and obese pregnancies. Methods: Human umbilical vein endothelial cells (unpassaged, P0-HUVECs; 5-7 days of culture, P1-HUVECs) were isolated immediately after delivery from normotensive (NT; 39±0.5 wks) and PE (38±0.5 wks) pregnancies (lean and OB) with female (F) and male (M) fetuses. Expression of miR146a-5p was examined in P0-HUVECs using RT-qPCR (n=8-10/group). Bioinformatics analysis was performed with our existing RNAseq data to identify PE-dysregulated miR146a-5p target genes in HUVECs. Endothelial monolayer integrity (MI) responses to cytokines were examined in P1 HUVECs with and without miR146a-5p overexpression and knockdown (n=5-7/group/assay). Results: PE upregulated miR146a-5p in lean F-HUVECs, while downregulated miR146a-5p in obese M-HUVECs. PE differentially dysregulated vascular/endothelial function-associated miR146a-5p target genes (e.g., TNFα-/TGFβ-signaling pathways) in F&M HUVECs. PE further reduced the TNFα-weakened MI in F and M HUVECs in both lean and OB pregnancies. TGFβ1 strengthened MI only in F-HUVECs, which was abolished in lean PE-F-HUVECs and was further decreased in OB PE-F-HUVEC. Knockdown of miR146a-5p rescues the PE-impaired MI responses to TNF-α and TGF-β1 in lean F-HUVECs but only rescues PE-impaired MI responses to TGF-β1 in OB F-HUVECs. Conclusions: MiR146a-5p plays important roles in mediating PE-induced fetal sex-specific fetal endothelial dysfunction in lean and obese pregnancies.