Neutrophil membrane-coated nanoparticles inhibit synovial inflammation and alleviate joint damage in inflammatory arthritis

Summary

This preclinical study addresses the limited response to single-cytokine blockade in rheumatoid arthritis by creating a broad decoy for inflammatory signals. Natural neutrophil membrane was fused onto polymeric nanoparticle cores, preserving the source cell's antigenic exterior and membrane functions. Because many inflammatory molecules normally bind or act on neutrophils, the coated particles could intercept multiple proinflammatory cytokines rather than inhibit one selected target. The formulation suppressed synovial inflammation, penetrated deeply into cartilage matrix, and protected cartilage from structural damage. Therapeutic activity was demonstrated in both collagen-induced arthritis and a human-transgenic mouse model, where treatment reduced joint injury and overall disease severity. The principal finding is that a neutrophil-like surface can neutralize a network of inflammatory mediators while also reaching the tissue compartment requiring protection. Its significance is a broad-spectrum anti-inflammatory strategy matched to the complexity of cytokine interactions in arthritis, potentially avoiding the need to predict one dominant mediator. The abstract does not identify the neutralized cytokines, quantify efficacy against anti-cytokine biologics, explain cartilage penetration, or report dosing, infection risk, immune consequences, and long-term joint outcomes.