Engineered Platelet Microparticle-Membrane Camouflaged Nanoparticles for Targeting the Golgi Apparatus of Synovial Fibroblasts to Attenuate Rheumatoid Arthritis.

Synovial fibroblasts in rheumatoid arthritis (RA) joints mediate synovial hyperplasia, progressive joint destruction, and the potential spread of disease between joints by producing multiple pathogenic proteins. Here, we deliver all-trans retinoic acid (ATRA) to selectively down-regulate these pathogenic factors, with a Golgi-targeting platelet microparticle-mimetic nanoplatform (termed Gol-PMMNP) which comprises a nanoparticle core and a platelet microparticle membrane coating labeled with a Golgi apparatus-targeting peptide. Gol-PMMNPs are shown to target synovial fibroblasts derived from RA patients via integrin α2β1-mediated endocytosis and accumulate in the Golgi apparatus by retrograde transport. ATRA-loaded Gol-PMMNPs (ATRA-Gol-PMMNPs) cause structural disruption of the Golgi apparatus, leading to an efficient reduction of pathogenic protein secretion in RA synovial fibroblasts. In rats with collagen-induced arthritis, Gol-PMMNPs display an arthritic joint-specific distribution, and ATRA-Gol-PMMNPs effectively reduce concentrations of pathogenic factors therein, including inflammatory cytokines, chemokines, and matrix-degrading enzymes within these joints. Additionally, ATRA-Gol-PMMNP treatment results in inflammatory remission and decreased bone erosion in both arthritic and proximal joints. Furthermore, ATRA-Gol-PMMNPs induce negligible toxicity to major organs. Taken together, ATRA-Gol-PMMNPs inhibit the progression of RA through reducing the production of multiple pathogenic mediators by synovial fibroblasts.