Sustained codelivery of heat shock protein peptide and rapamycin via nano-in-hydrogel induces immune tolerance in rheumatoid arthritis.

Co-delivery of autoantigens with immunomodulators via nanovaccines presents a promising strategy for inducing tolerogenic immune responses in rheumatoid arthritis (RA). Conventional subcutaneous administration often results in rapid systemic dissemination, limiting efficacy in targeting lymphatic tissues. Here, we developed a tolerogenic nanovaccine-in-hydrogel delivery system comprising heat shock protein peptide-coated, rapamycin-encapsulated polymeric vesicles (HRV@gel) designed for sustained exposure to lymph nodes. This system aims to promote the differentiation of tolerant dendritic cells (tolDCs) and activation of regulatory T cells (Tregs), thereby reestablishing immune tolerance to combat RA. The nanovaccines revealed an average size of 66 nm and demonstrated sustained release from the hydrogel matrix. In vitro studies confirmed the efficient internalization of HRV by dendritic cells (DCs), where HSP peptides underwent cleavage by intracellular enzymes and presented on the DCs surface. Notably, HRV effectively inhibited DCs activation, downregulated MHC II expression, and reduced pro-inflammatory cytokine secretion. In vivo analysis showed that subcutaneous injection of HRV@gel achieved prolonged exposure compared to HRV alone. In CIA mouse models, two injections of HRV@gel significantly alleviated inflammation, promoted durable local and peripheral immune tolerance, and protected joint tissues. This HRV@gel nano-in-hydrogel strategy showcases a compelling tolerogenic therapy for potent and long-lasting immunological intervention in RA.