A Functional Polymorphism rs145204276 in the Promoter of Long Noncoding RNA GAS5 Is Associated with an Increased Risk of Ischemic Stroke.

Long noncoding RNAs (lncRNAs) play crucial roles in the regulation of pathological process of ischemic stroke (IS) via affecting cell apoptosis, inflammation, cell death, and angiogenesis. LncRNA growth arrest-specific 5 (GAS5) was observed to be up-regulated in IS, acting as a competing endogenous RNA for miR-137 to mediate the Notch1 signaling pathway. In this study, we aimed to whether an insertion/deletion polymorphism (rs145204276) in the promoter of GAS5 was related to the risk of IS. The rs145204276 was genotyped using polymerase chain reaction (PCR)-polyacrylamide gel electrophoresis in 509 patients with IS and 668 healthy controls with frequencies matched to cases regarding age, gender, living area, and ethnicity. The GAS5 expression levels were determined using qPCR and relative luciferase activity was measured using the Dual Luciferase assay system. The presence of del/del genotype and del allele was associated with an increased risk of IS [del/del versus ins/ins: adjusted odds ratio (OR) = 2.06, 95% confidence interval (CI): 1.37-3.11; recessive model: adjusted OR = 2.07, 95% CI: 1.41-3.04; del versus ins: adjusted OR = 1.31, 95% CI: 1.08-1.57]. Results from logistic regression analysis identified risk factors for IS, including hypertension, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and rs145204276 del/del genotype. Furthermore, patients carrying rs145204276 del/del genotype had significantly higher levels of GAS5 and cells transfected with rs145204276 del allele exhibited a larger increase in luciferase activity. These findings indicate that rs145204276 del allele exhibited a significant association with an increased IS susceptibility by elevating the transcriptional activity and subsequently enhancing the expression of lncRNA GAS5.