BMSC-derived EVs alleviate doxorubicin-induced cardiotoxicity via miR-210-3p involving the ACVR1B-SMAD3-PGC-1α signaling axis

Doxorubicin-induced cardiotoxicity (DIC) limits the clinical use of doxorubicin, yet no specific therapeutic interventions are available. Although the cardioprotective role of miR-210 and the therapeutic potential of stem cell-derived extracellular vesicles have been reported, the specific downstream effectors and pathways mediating the cardioprotective effects of BMSC-EVs against DIC remain poorly understood. DIC models were established in HL-1s and C57BL/6 mice. High-throughput RNA sequencing combined with EVs uptake assay and miRNA FISH staining was performed to screen functional miRNAs delivered by BMSC-EVs. Gain- and loss-of-function approaches were performed using miR-210-3p mimics, inhibitors, and ACVR1B siRNA. Cell viability and death, ROS and mitochondrial ROS, mitochondrial membrane potential, and mitochondrial function were assessed by fluorescence staining and western blotting. Bioinformatic analysis and dual-luciferase reporter assays were further applied to identify the downstream target genes of BMSC-EV-derived miRNAs. Molecular mechanisms involving the ACVR1B/SMAD3/PGC-1α signaling pathway were further investigated by RT–qPCR and Western blot. This study verified that miR-210-3p acts as one of the critical effector molecules mediating the cardioprotective effects of bone marrow mesenchymal stem cell-derived EVs. Both miR-210-3p overexpression and BMSC-EV treatment markedly alleviated cardiomyocyte death and mitochondrial dysfunction by DIC, whereas inhibition of miR-210-3p aggravated cellular injury. In vivo, miR-210-3p overexpression significantly improved cardiac dysfunction, attenuated myocardial fibrosis, and mitigated mitochondrial dysfunction. Mechanistically, miR-210-3p directly targeted the 1573-nt site within the ACVR1B 3’UTR, thereby suppressing ACVR1B expression. Downregulation of ACVR1B subsequently inhibited SMAD3 phosphorylation, relieved repression of PGC-1α, and restored mitochondrial biogenesis and respiratory function. Moreover, ACVR1B knockdown effectively rescued the aggravated DIC induced by miR-210-3p inhibition. BMSC-EVs-derived miR-210-3p attenuates doxorubicin-induced mitochondrial damage, an effect that was accompanied by suppression of the ACVR1B–SMAD3 cascade and restoration of PGC-1α. This study proposes a potential “EVs–miR-210-3p–ACVR1B” regulatory axis, highlighting candidate targets for further therapeutic exploration in DIC.