Objective: Long non-coding RNAs (lncRNAs) are involved in the development of myocardial ischemia/reperfusion (I/R) injury. In this study, we aimed to investigate the roles and underlying mechanisms of five prime to Xist (FTX) in myocardial I/R injury using cardiomyocyte hypoxia/reoxygenation (H/R) model.
Materials and methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to determine the expression of FTX, microRNA-410-3p (miR-410-3p) and fragile X mental retardation 1 (Fmr1) mRNA. Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis were employed to evaluate cell proliferation and apoptosis, respectively. Western blot assay was conducted to examine the protein levels of apoptosis-associated factors and Fmr1. Specific kits were used to detect the levels of oxidative stress-associated factors. Dual-luciferase reporter assay was performed to verify the association between miR-410-3p and FTX or Fmr1.
Results: FTX was reduced in myocardial I/R injury patients' serum and H/R-stimulated H9c2 cells. FTX overexpression relieved cell damage caused by H/R treatment through inducing cell proliferation and repressing cell apoptosis and oxidative stress in H9c2 cells. FTX was a sponge for miR-410-3p and the impact of FTX overexpression on H/R-induced cell injury was abolished by miR-410-3p elevation in H9c2 cells. Fmr1 was identified as a target of miR-410-3p and Fmr1 knockdown reversed the effect on H/R-induced cell damage mediated by miR-410-3p inhibition in H9c2 cells. Moreover, FTX positively regulated Fmr1 expression through sponging miR-410-3p in H9c2 cells.
Conclusions: FTX regulated H/R-induced cardiomyocyte damage by upregulating Fmr1 via sponging miR-410-3p.