Apoptotic extracellular vesicles derived from anti-inflammatory empowered immortalized mesenchymal stem cells ameliorate rheumatoid arthritis

The treatment of rheumatoid arthritis (RA) remains a clinical challenge due to the lack of long-term effective therapeutic approaches. Stem cell-derived apoptotic vesicles show promising therapeutic potential for inflammatory diseases, including arthritis. However, large-scale and low-cost production of safe and effective stem cell apoptotic vesicles presents significant challenges. In this study, we generated immortalized mesenchymal stem cells (IMSCs) through genetic engineering (SV40LT+hTERT transfection). The IMSCs exhibited long-term stable proliferative capacity. Furthermore, we primed IMSCs with a combination of IFN-γ and TNF-α and then induced them to undergo apoptosis, thereby obtaining function-enhanced IMSC-derived apoptotic vesicles (EIMSCs-apoEVs). Proteomic analysis revealed that EIMSCs-apoEVs were enriched in immunomodulatory factors and tissue repair proteins. In vitro studies demonstrated that EIMSCs-apoEVs promoted macrophage polarization from the M1 to M2 phenotype and modulated T-cell functions. Additionally, EIMSCs-apoEVs enhanced the functional capacity of joint injury repair cells (BMSCs and chondrocytes). Finally, in a mouse RA model, EIMSCs-apoEVs exhibited strong safety, significantly improved synovial inflammation, promoted tissue regeneration, and maintained joint structural integrity. In summary, our study developed a low-cost, scalable method for producing safe mesenchymal stem cell apoptotic vesicles with anti-inflammatory and tissue repair capabilities. We demonstrated that EIMSCs-apoEVs are safe and effective for treating RA in mice, offering a novel clinical strategy for RA therapy.