Long noncoding RNA TUG1 contributes to cerebral ischaemia/reperfusion injury by sponging mir-145 to up-regulate AQP4 expression

Emerging studies have shown that long noncoding RNA (lncRNA) TUG1 (taurine-up-regulated gene 1) plays critical roles in multiple biological processes. However, the expression and function of lncRNA TUG1 in cerebral ischaemia/reperfusion injury have not been reported yet. In this study, we found that LncRNA TUG1 expression was significantly up-regulated in cultured MA-C cells exposed to OGD/R injury, while similar results were also observed in MCAO model. Mechanistically, knockdown of TUG1 decreased lactate dehydrogenase levels and the ratio of apoptotic cells and promoted cell survival in vitro. Moreover, knockdown of TUG1 decreased AQP4 (encoding aquaporin 4) expression to attenuate OGD/R injury. TUG1 could interact directly with miR-145, and down-regulation of miR-145 could efficiently reverse the function of TUG1 siRNA on AQP4 expression. Finally, the TUG1 shRNA reduced the infarction area and cell apoptosis in I/R mouse brains in vivo. In summary, our results suggested that lncRNA TUG1 may function as a competing endogenous RNA (ceRNA) for miR-145 to induce cell damage, possibly providing a new therapeutic target in cerebral ischaemia/reperfusion injury.