Dual-functional fusion extracellular vesicles ameliorate osteoarthritis via synergistic macrophage reprogramming and chondroprotection

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by progressive cartilage destruction and synovial inflammation. Macrophage polarization plays a critical role in OA progression, where pro-inflammatory M1 macrophages exacerbate joint damage, while anti-inflammatory M2 macrophages promote repair. Extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (HEV) possess immunomodulatory and chondroprotective potential but suffer from poor targeting and rapid clearance in vivo. To overcome these limitations, we developed an extrusion-generated hybrid EV system (MHEV) by merging EVs from M2 macrophages (MEV) with HEV. Proteomic profiling indicated that MHEV retains candidate targeting-associated molecular features from MEV, while also containing candidate functional proteins such as THBS2 and TGFB1 from the parental EV populations. In vitro, MHEV synergistically promoted M2 polarization and suppressed M1 polarization in macrophages more effectively than MEV or HEV alone, and activated Wnt/β-catenin signaling in macrophages and TGF-β/Smad signaling in chondrocytes. Moreover, MHEV enhanced chondrocyte viability, migration, and matrix synthesis under inflammatory conditions. In vivo, MHEV exhibited significantly improved accumulation in OA joints compared to HEV or a simple mixture of MEV + HEV, leading to enhanced modulation of synovial macrophage polarization, activation of reparative signaling pathways, attenuation of cartilage degradation, and reduction of osteophyte formation in a murine OA model. This study presents a targeted EV hybridization platform that combines the inflammatory homing capability of MEV with the multifaceted therapeutic activity of HEV, offering a promising strategy for precise OA treatment.