Objective To explore the mechanism of microRNA(miRNA)-365a-3p affecting the function of vascular endothelial cells involved in the pathogenesis of preeclampsia(PE).Methods Primary human umbilical vein endothelial cells(HUVECs)were set as a NC group(transfected miR-365a-3p NC),a mimics group(trans-fected miR-365a-3p mimics)and a inhibitor group(transfected miR-365a-3p inhibitor).Logarithmic HUVECs cells were set as the blank group.The cell proliferation,migration and angiogenesis in each group were detected.Dual luciferin assay verified the targeting relationship between miR-365a-3p and downstream gene.The protein expressions of TGF-β1,Smad4 and Smad7 in each group were detected.Results Compared with the blank group and the NC group,the absorbance value and mobility of 24,48 and 72 h were decreased(P＜0.05),the number of tubular structures per field were decreased in the mimics group(P＜0.05),the absorbance value and mobility of 24,48 and 72 h were increased(P＜0.05),and the number of tubular structures per field were increased in the inhibitor group(P＜0.05).Dual luciferin assay showed that Smad7 was a target gene of miR-365a-3p.Compared with the blank group and the NC group,the protein expressions of TGF-β1 and Smad4 in the mimics group were increased(P＜0.05),while the protein expression of Smad7 was decreased(P＜0.05).The protein expression levels of TGF-β1 and Smad4 in the inhibitor group were decreased(P＜0.05),while the protein expression levels of Smad7 were increased(P＜0.05).Conclusion miR-365a-3p may affect the function of vascular endothelial cells by regulating the downstream TGF-β signaling pathway,and thus participate in the pathogenesis of PE.