Engineering CCR2/IFN-γ overexpression in enucleated mesenchymal stem cells enhances therapy for rheumatoid arthritis

Mesenchymal stem cells (MSCs) offer a promising therapy for rheumatoid arthritis (RA). However, their therapeutic potential is hindered by initial trapping in lung capillaries, which may reduce efficacy and increase risks of complications, such as unwanted differentiation and malignancy. Additionally, engineering MSCs to enhance therapeutic effects introduces further safety concerns and regulatory challenges for clinical approval. In this study, we generated enucleated human umbilical cord-derived MSCs overexpressing CCR2 and IFN-γ (En-MSCs^C/I), which retained essential organelles and exhibited immune regulatory, paracrine, and homing capabilities. Intravenous administration of either MSCs or En-MSCs^C/I alleviated synovitis in a male rat model of RA by modulating immune and inflammatory processes of fibroblast-like synoviocytes and myeloid cells, as revealed by single-cell RNA sequencing analysis. En-MSCs^C/I promoted the secretion of factors such as SEMA3E, potentially contributing to synovitis amelioration and cartilage regeneration. Compared to MSCs, En-MSCs^C/I demonstrated superior migration to injured joints and unique regulatory signature for cartilage regeneration. Our study suggests that En-MSCs^C/I may offer enhanced therapeutic effects for RA-related cartilage damage while maintaining favorable safety profiles.