Targeted Macrophage Re‐programming: Synergistic Therapy with Methotrexate and RELA siRNA Folate‐Liposome in RAW264.7 Cells and Arthritic Rats

Abstract Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by joint inflammation and destruction. Current treatments, such as Methotrexate (MTX), though effective, often face limitations such as high plasma C max and lack of sustained release. This study explores a synergistic approach to RA therapy using folate‐liposomal co‐delivery of MTX and RELA siRNA (short interfering RNA), targeting RAW264.7 macrophage repolarization via nuclear factor kappa B (NF‐κB) pathway inhibition. Extensive in vitro characterizations demonstrate the stability and biocompatibility of this therapy via folate‐liposomes. In the collagen‐induced arthritis (CIA) rat model, treatment leads to reduced synovial inflammation and improved mobility. The combined MTX and RELA siRNA approach indirectly inhibits inflammatory cytokines, rheumatoid factor (RF), and C‐reactive protein (CRP). Targeted macrophage delivery shows marked therapeutic effects in RAW264.7 murine macrophages, potentially modulating M1 to M2 polarization. This research presents a promising avenue for innovative RA therapies by inhibiting the inflammatory cascade and preventing joint damage.