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MEG3 damages fetal endothelial function induced by gestational diabetes mellitus via AKT pathway.

OBJECTIVE
To explore the role of maternally-expressed gene 3 (MEG3) in fetal endothelial dysfunction induced by gestational diabetes mellitus (GDM) and its underlying mechanism.


PATIENTS AND METHODS
Human umbilical vein endothelial cells (HUVECs) were extracted from GDM pregnancies and normal pregnancies. Cell proliferation, apoptosis, migration and angiogenesis of HUVECs were detected by cell counting kit-8 (CCK-8), enzyme-linked immunosorbent assay (ELISA), wound healing and tube formation assay, respectively. MEG3 expressions in HUVECs extracted from 16 GDM pregnancies and 18 normal pregnancies were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Besides, angiogenesis and MEG3 expression in HUVECs treated with glucose were detected, respectively. Proliferation, apoptosis, migration and angiogenesis were also detected after HUVECs were transfected with MEG3 lentivirus. Target genes of MEG3 were predicted by bioinformatics method and further verified by luciferase reporter gene assay. The protein expression of possible signaling pathway was detected by Western blot.


RESULTS
HUVEC cells extracted from GDM pregnancies presented increased apoptosis and decreased proliferation, migration and angiogenesis compared with those from healthy pregnancies. Meanwhile, MEG3 was overexpressed in HUVECs extracted from GDM pregnancies compared with that of healthy pregnancies. High dose of glucose treatment led to reduced angiogenesis and elevated MEG3 expression in HUVECs. MEG3 overexpression further promoted apoptosis, but inhibited proliferation, migration and angiogenesis of HUVECs. By bioinformatics and luciferase reporter gene assay, microRNA-370-3p was found to be the target gene of MEG3 and directly targeted on AFF1. Moreover, MEG3 overexpression led to downregulated microRNA-370-3p and upregulated AFF1 mainly through inhibiting PI3K/AKT pathway.


CONCLUSIONS
MEG3 is overexpressed in HUVECs extracted from GDM pregnancies. MEG3 damages fetal endothelial function through targeting microRNA-370-3p and AFF1 via PI3K/AKT pathway.