Inflammation-targeted vesicles for co-delivery of methotrexate and TNF-α siRNA to alleviate collagen-induced arthritis

Abstract

Rheumatoid arthritis (RA) is an autoimmune disease that has a complex pathogenesis and remains tough to treat. The clinical treatments with e.g. methotrexate (MTX) and TNF-α antibodies show fractional responses and lessen the symptoms only to a certain extent. Here, we developed inflammation-targeted vesicles codelivering methotrexate and TNF-α small interfering RNA (siTNFα) (ITV-MT) for effective ablation of collagen-induced arthritis (CIA) in mice. ITV-MT with tetra-mannose ligand and high loading of MTX (17.1 wt%) and siTNFα (9.0 wt%) displayed a small and uniform size (53 nm) and augmented uptake by inflammatory macrophages leading to superior regulation of macrophage phenotype from M1 to M2 in vitro compared to monotherapies. The intravenous injection of ITV-MT revealed clearly enhanced accretion in the inflamed joints. Interestingly, ITV-MT effectively repolarized M1 macrophages to M2 type, markedly reduced proinflammatory cytokine levels, and significantly attenuated symptoms including joint swelling, arthritis scores and bone damage in the CIA mouse models, by concurrently downregulating both adenosine and TNF-α pathways. This study highlights inflammation-targeted vesicles codelivering methotrexate and TNFα siRNA as a potential strategy to improved RA treatment.

Statement of significance

Rheumatoid arthritis (RA) is regarded as an incurable disease, often referred to as an "incurable cancer". Current therapies, such as methotrexate (MTX) and anti-TNFα monoclonal antibodies, exhibit limited efficacy and severe adverse effects. The distinct physiochemical properties of MTX and siTNFα hinder their codelivery to RA joints and inflammatory cells. Here, we engineered inflammation-targeted vesicles (ITV-MT) for the codelivery of MTX and siTNFα to enhance therapeutic outcomes. Our findings reveal that ITV-MT significantly improves the drug uptake by macrophages, facilitating repolarization from M1 to M2 phenotypes. In CIA models, ITV-MT effectively downregulated proinflammatory cytokines while upregulating anti-inflammatory cytokines in RA joints, inhibited inflammatory cell infiltration in the synovium and protected against bone erosion. This study highlights that inflammation-targeted co-delivery of small molecular anti-RA agents and RNAi therapeutics may offer a compelling alternative to existing RA treatments, representing a promising strategy for RA treatment.