The NSUN5-FTH1/FTL pathway mediates ferroptosis in bone marrow-derived mesenchymal stem cells

Ferroptosis is a type of cell death induced by the iron-dependent accumulation of lipid hydroperoxides and Reactive Oxygen Species (ROS) in cells. Inhibiting Ferroptosis is important for improving the survival of transplanted bone marrow-derived mesenchymal stem cells (BMSCs). Although it is known that NOP2/Sun RNA methyltransferase 5 (NSUN5) post-transcriptionally regulates Ferroptosis in BMSCs through RNA methylation, the precise mechanisms underlying these effects have not been reported. In this study, we demonstrate that NSUN5 is downregulated in erastin-induced Ferroptosis in BMSCs. Ferroptosis was inhibited by the overexpression of NSUN5 or ferritin heavy chain/light-chain (FTH1/FTL) and was enhanced by NSUN5 knockdown. RNA immunoprecipitation experiments revealed that NSUN5 binds to FTH1/FTL, while NSUN5 depletion reduced the levels of 5-methylcytosine in FTH1/FTL RNA and increased intracellular iron concentrations, resulting in the downregulation of Glutathione Peroxidase 4 (GPX4) and the accumulation of ROS and lipid peroxidation products. Co-immunoprecipitation experiments demonstrated that the recognition of FTH1 and FTL by NSUN5 is dependent on the recruitment of tumor necrosis factor receptor-associated protein 1 (TRAP1). These results suggested that the NSUN5-FTH1/FTL pathway mediates Ferroptosis in BMSCs and that the therapeutic targeting of components of this pathway may promote resistance to Ferroptosis and improve the survival of transplanted BMSCs.