The BMSC-derived exosomal lncRNA Mir9-3hg suppresses cardiomyocyte ferroptosis in ischemia-reperfusion mice via the Pum2/PRDX6 axis

Background and aims The exosomal long noncoding RNAs (lncRNAs) have been reported to have cardioprotective effects on ischemia-reperfusion (I/R) injury by hindering ferroptosis, but the role of lncRNA Mir9-3 host gene (Mir9-3hg) in cardiac I/R injury remains unclear. Methods and results Exosomes were extracted from mouse bone marrow mesenchymal stem cells (BMSCs) and identified by detecting the exosome specific marker levels, and the results showed that Mir9-3hg was highly expressed in BMSCs-Exo. Hypoxia/reoxygenation (H/R)-treated HL-1 mouse cardiomyocytes were incubated with exosomes extracted from BMSCs transfected with Mir9-3hg siRNA. BMSCs-Exo incubation observably facilitated cell proliferation, increased glutathione (GSH) content, and reduced iron ion concentration, reactive oxygen species (ROS) level and ferroptosis marker protein levels in H/R-treated cells, while interfering Mir9-3hg reversed these effects. RNA binding protein immunoprecipitation assay was found that Mir9-3hg bound with pumilio RNA binding family member 2 (Pum2) protein and downregulated Pum2 expression. Silence of Pum2 reversed the effects of Mir9-3hg inhibition on cell functions. Chromatin immunoprecipitation assay was revealed that Pum2 bound with peroxiredoxin 6 (PRDX6) promoter and restrained PRDX6 expression. Silence of PRDX6 reversed the improved effects of Pum2 downregulation on cell functions. Additionally, BMSCs-Exo treatment ameliorated cardiac function in I/R-treated mice by inhibiting cardiomyocyte ferroptosis. Conclusions BMSCs-Exo treatment attenuates I/R-induced cardiac injury by inhibiting cardiomyocyte ferroptosis through modulating the Pum2/PRDX6 axis, thereby ameliorating cardiac function.