Adipose-derived stem cell exosomes mitigate ferroptosis and enhance osteogenesis via miR-215-5p-mediated ubiquitin-specific protease 1 suppression

Osteoporosis (OP) is a metabolic bone disease characterized by impaired bone formation and excessive resorption. Ferroptosis has been implicated in osteoblast dysfunction. Adipose-derived stem cell exosomes (ADSC-exos) have emerged as promising regenerative therapies. This study investigated whether ADSC-exos alleviate ferroptosis and promote osteogenic differentiation by modulating the miR-215-5p/USP1/PTEN/AKT/GSK3β/NRF2 pathway. Human ADSC-exos were evaluated using transmission electron microscopy, nanoparticle tracking analysis, and western blot. Ferroptosis was induced in MG63 cells using ferric ammonium citrate (FAC). Cell viability, lipid peroxidation, and osteogenic differentiation were evaluated using the CCK-8 assay, C11-BODIPY staining, malondialdehyde quantification, ALP staining, and Alizarin Red S staining. The effects of ADSC-exos on PTEN ubiquitination and AKT/GSK3β/NRF2 pathway activation were assessed using western blot, RT-qPCR, and immunoprecipitation. ADSC-exos significantly improved osteoblast viability, reduced lipid peroxidation, and enhanced osteogenic differentiation in FAC-treated MG63 cells. Dual-luciferase reporter assay identified miR-215-5p as a key exosomal cargo that targets USP1. Mechanistically, ADSC-exos downregulated USP1, leading to PTEN ubiquitination and degradation, thereby activating the AKT/GSK3β/NRF2 signaling pathway. USP1 overexpression reversed the protective effects of ADSC-exos, confirming that miR-215-5p-mediated USP1 inhibition plays a crucial role in regulating ferroptosis and osteogenic differentiation. In conclusion, ADSC-exos diminish ferroptosis and enhance osteogenic differentiation by delivering miR-215-5p, which inhibits USP1, promotes PTEN ubiquitination, and activates the AKT/GSK3β/NRF2 pathway. These findings provide new insights into the mechanisms by which ADSC-exos promote bone repair and highlight their potential as an innovative treatment for OP.