Long non-coding RNA MALAT1 affects intermittent hypoxia-induced endothelial injury by regulating miR-142-3p/HMGB1.

Background: Obstructive sleep apnea (OSA) is a risk factor for atherosclerosis. Long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is strongly linked to endothelial cell functions. However, the function of MALAT1 in intermittent hypoxia (IH) associated vascular endothelial injury has not been explored yet. The current study makes great attempts to investigate the function of MALAT1 in IH-induced endothelial injury and its latent control network.

Methods: To mimic the effect of OSA, we cultured the human umbilical vein endothelial cells (HUVECs) under intermittent hypoxia. Western blot was applied to measure the expression level of associated proteins including capase-3, Bax, Bcl-2 while qRT-PCR was used in measurement of MALAT1 and miR-142-3p. Cell Counting Kit-8 (CCK-8) was carried out in assessing cell viability. Dual-luciferase reporter assay was applied to verify the relationships among high mobility group box (HMGB)1 and MALAT1, miR-142-3p.

Results: IH treatment significantly reduced cell viability but enhanced cell apoptosis in HUVECs. Concomitantly, MALAT1 was significantly upregulated in IH-treated HUVECs. Further experiment showed that MALAT1 knockdown augmented IH-induced injury of HUVECs. In addition, it was confirmed by dual-luciferase reporter assay that MALAT1 interacted with miR-142-3p directly. Besides, inhibition of miR-142-3p alleviated damage induced by MALAT1 knockdown in IH-treated HUVECs. Finally, miR-142-3p interacted with HMGB1 directly and inhibition of HMGB1 protein expression mediated by MALAT1 knockdown was reversed by miR-142-3p inhibitor.

Conclusions: IH resulted in increased expression of MALAT1 in HUVECs. MALAT1 knockdown augmented IH-induced injury of HUVECs. MALAT1 exerted its effects on IH-treated HUVECs via miR-142-3p/HMGB1.