Elevated Expression of lncRNA MEG3 Induces Endothelial Dysfunction on HUVECs of IVF Born Offspring via Epigenetic Regulation

Background: The cardiovascular dysfunction in children born after in vitro fertilization (IVF) has been of great concern, in our study, we aim to explore potential molecular mechanism for such long-term outcomes. Methods：Real-time qPCR was used to test long non-coding RNA MEG3 and endothelium-derived factors, endothelial nitric oxide synthase (eNOS), endothelin-1(ET1), vascular endothelial growth factor (VEGF). Primary HUVEC after caesarean section was treated with different estradiol concentrations in vitro. Besides, knockdown of MEG3 on HUVEC provided further evidence between MEG3 expression and alteration of NO, ET1, VEGF. Then, by using pyrosequencing, we detected MEG3 promoter methylation status.Results: We found that the expression level of MEG3 was higher in human umbilical vein endothelial cells (HUVECs) of IVF offspring than that in spontaneously born offspring. Furthermore, we found decreased expression of eNOS, VEGF, elevated expression of ET1 in HUVECs from IVF offspring compared to spontaneously born offspring. We further confirmed the results from in-vivo experiments by demonstrating that high-estradiol intrauterine environments lead to abnormal expression of MEG3 and endothelium-derived factors. Meanwhile, silencing MEG3 expression decreased ET1 expression, and increased nitrite, nitrate, VEGF secretion, which could correct the effect we observed in-vivo. With pyrosequencing technology, we found that elevated expression of MEG3 in IVF offspring derived HUVECs was the result of hypomethylation of the MEG3 promoter. Conclusions: Our results demonstrated that higher expression of MEG3 in IVF-born HUVECs, accompanied by lower secretion of eNOS, VEGF, and higher secretion of ET1, which is closely related with endothelial dysfunction, which together provide a potential mechanism addressing high-risk of hypertension in IVF offspring.