Highly effective rheumatoid arthritis therapy by peptide-promoted nanomodification of mesenchymal stem cells.

Traditional medication is not satisfied in rheumatoid arthritis (RA) therapy due to its long-term side effects and failure in cartilage repair. Nanomodification of mesenchymal stem cells (MSCs) holds promise for lifting such hurdles but delivering therapeutic nanomaterials (NPs) into MSCs remains challenging in this new strategy. Here, we show that CuS@MnO2 NPs functionalized with a short phage-selected MSC-targeting peptide enabled the NPs to be uptaken by MSCs. The resultant NP-modified MSCs, further loaded with metformin, significantly improved stem cell therapy of RA. Specifically, the NP-modified MSCs survived the RA-associated oxidized stress through regulating the stress by the superoxide dismutase (SOD)- and catalase (CAT)-like activity of the NPs. They also exhibited an increased capability of cell migration, anti-inflammation, and chondrogenesis due to the nanomodification, thereby effectively inhibiting synovial inflammation and reducing cartilage erosion to relieve RA symptoms in two rat models 28 days post intravenous injection. Our peptide-promoted NP-modified MSCs may be used to enhance therapeutic effects in treating not only RA but also other degenerative and inflammatory diseases.