USP22 alleviates oxidative stress-induced BMSCs senescence by stabilizing SPI1 protein.
BACKGROUND: Therapeutic efficacy of bone marrow mesenchymal stem cell (BMSC) transplantation is often compromised by cellular senescence and diminished osteogenic potential induced by oxidative stress. Nevertheless, the underlying molecular mechanisms remain poorly understood. This study explores the role of ubiquitin-specific peptidase 22 (USP22) in regulating oxidative stress-induced BMSCs senescence. METHODS: BMSCs were exposed to H2O2 to mimics oxidative stress conditions. An ovariectomy‑induced osteoporotic rat model was established. Cell viability was assessed by CCK8 assay. ROS level and NAD+ level were measured by the DHE probe and kit, respectively. SA-β-gal staining was employed to detect cellular senescence. Mineralization was determined using ARS staining. Protein-DNA interactions (SPI1-NAMPT promoter) were examined through ChIP and luciferase reporter assays. Co-IP and ubiquitination assays were performed to validate USP22-SPI1 binding and post-translational modifications. RESULTS: SPI1 expression declined in H2O2-treated BMSCs and osteoporotic rat model, and its overexpression rescued H2O2-induced BMSCs senescence and osteogenic differentiation impairment. Mechanistically, SPI1 mediated protection on oxidative stress-induced BMSCs senescence by transcriptionally activating NAMPT expression and elevating NAD+ level. In addition, USP22 stabilized SPI1 protein through deubiquitination modification. As expected, USP22 overexpression alleviated oxidative stress-induced BMSCs senescence and osteogenic differentiation impairment, while these effects were reversed by SPI1 knockdown. CONCLUSION: USP22 mitigated oxidative stress-induced BMSCs senescence and preserved osteogenic capacity by promoting NAMPT transcription through deubiquitinating and stabilizing SPI1 protein.