lncRNA XIST knockdown suppresses hypoxia/reoxygenation (H/R)‐induced apoptosis of H9C2 cells by regulating miR ‐545‐3p/ G3BP2

This study was aimed at determining the roles and functions of lncRNA XIST/miR‐545‐3p/G3BP2 axis during hypoxia/reoxygenation (H/R)‐induced H9C2 cell apoptosis. H9C2 cells were distributed into two groups, the H/R injury and control groups. High‐throughput lncRNA sequencing was applied in the determination of differentially expressed lncRNAs between H/R‐induced H9C2 cells and normal H9C2 cells. Real‐time polymerase chain reactions (RT‐PCR) were used to confirm the expression levels of lncRNA XIST in H/R‐induced H9C2 cells. H9C2 cells were then transfected with lncRNA XIST recombinant plasmid (lncRNA XIST), sh‐LINC XIST, agomiR‐545‐3p, antagomiR‐545‐3p, pcDNA‐G3BP2, sh‐G3BP2, and a corresponding negative control (NC). Bioinformatic analyses revealed that MiR‐545‐3p was a target for lncRNA XIST. This finding was confirmed by dual‐luciferase reporter assay. The degree of cell apoptosis was evaluated by a flow cytometer. RT‐PCR and western blot were performed to assess the apoptotic‐related proteins in each group. A total of 859 differentially expressed lncRNAs (up‐regulated = 502, down‐regulated = 357) were identified. LncRNA XIST was found to be down‐regulated in H/R‐induced H9C2 cells while miR‐545‐3p was distinctly up‐regulated. miR‐545‐3p was established to be a direct target for LncRNA XIST. LncRNA XIST significantly enhanced the apoptotic rate, while its inhibition suppressed the apoptotic rate. AgomiR‐545‐3p partially blocked the lncRNA XIST and enhanced the apoptosis of H/R‐induced H9C2 cells. Moreover, miR‐545‐3p was shown to be a direct target for G3BP2. The overexpression of G3BP2 partially reversed the apoptotic effects of miR‐545‐3p on H/R‐induced H9C2 cells. lncRNA XIST/miR‐545‐3p/GBP2 was found to be an apoptotic regulator in H/R‐induced H9C2 cells.