Long non-coding RNA NORAD protects against cerebral ischemia/reperfusion injury induced brain damage, cell apoptosis, oxidative stress and inflammation by regulating miR-30a-5p/YWHAG

LncRNAs are identified as critical regulators in cerebral ischemia/reperfusion injury (CIRI). In this current work, SH-SY5Y cells suffered from oxygen-glucose deprivation/reperfusion (OGD/R) were applied to analyze the biological role of lncRNA NORAD and underlying molecular mechanism in CIRI in vitro. Levels of lncRNA NORAD, miR-30a-5p and YWHAG were measured using RT-qPCR. Bioinformatics analysis predicted the binding sites of lncRNA NORAD to miR-30a-5p and miR-30a-5p to YWHAG. Luciferase reporter assay verified the binding relationships among lncRNA NORAD, miR-30a-5p and YWHAG. Additionally, cell viability was determined using CCK-8 assay, and cell apoptosis was assessed using TUNEL staining and western blot analysis. Moreover, the levels of ROS, MDA, LDH and SOD as well as IL-1β, TNF-α, and IL-6 were assessed via application of the corresponding assay kits. Decreased cell viability and temporarily increased lncRNA NORAD level were observed in SH-SY5Y cells after OGD/R. It was demonstrated that lncRNA NORAD regulated YWHAG expression by sponging miR-30a-5p. Upregulation of lncRNA NORAD contributed to the enhancement of cell viability, the inhibition of cell apoptosis as well as the alleviation of oxidative stress and inflammation in OGD/R-injured SH-SY5Y cells, which were reversed upon elevation of miR-30a-5p. In contrast, downregulation of lncRNA NORAD reduced cell viability, promoted cell apoptosis as well as aggravated oxidative stress and inflammation under OGD/R challenge, and the functions of lncRNA NORAD knockdown in OGD/R injury were abolished by upregulation of YWHAG. Taken together, lncRNA NORAD exerted protective effects against OGD/R-induced neural injury by sponging miR-30a-5p to upregulate YWHAG expression.