Converging paths: Microneedle-based dual intervention of IL-23/IL-17 axis and granuloma formation in rheumatoid nodules

Rheumatoid nodules (RNs) are an extra-articular manifestation of rheumatoid arthritis and are frequently observed in patients with autoimmune and inflammatory conditions. The development of RNs involves several stages, including inflammation of blood vessels, cell death triggered by medications, and infiltration of inflammatory cells leading to nodule formation. Recent studies highlight the importance of the IL-23/IL-17 axis and the migration of chronic inflammatory cells in this process, forming palisading granulomas. Current treatments often fail to manage RNs effectively because they tend to reoccur and appear in multiple locations. This study proposes a new therapeutic strategy combining corticosteroid treatment with gene silencing therapy using small interfering RNA (siRNA) targeting IL-23. Targeting these inflammatory pathways simultaneously aims to reduce both the size and number of nodules, potentially shortening the treatment duration. An innovative delivery system utilizing lipid-polymer hybrid nanoparticles (LPNs) and hyaluronic acid-based dissolving microneedles (MNs) is proposed to be developed. The LPNs will be designed with DOTAP (1,2-dioleoyl-3-trimethylammonium propane) and DSPE-PEG (distearoyl-phosphoethanolamine-polyethylene glycol) as the lipid core, along with poly-lactic-co-glycolic acid (PLGA) polymer. These MN patches would improve the skin’s permeability, allowing LPN carrying the siRNA and corticosteroid to penetrate effectively. This non-invasive approach is expected to enhance the diffusion of LPNs into the skin, thereby increasing the availability of the therapeutic payload. Therefore, we hypothesize that targeting the IL-23/IL-17 axis and granuloma formation with the synergistic combination of targeted therapy and advanced delivery technology will revolutionize the treatment of RNs.