Development of pH-sensitive dextran-based methotrexate nanodrug for rheumatoid arthritis therapy through inhibition of JAK-STAT pathways

Rheumatoid arthritis (RA) is a chronic and symmetrical autoimmune disease that primarily characterized with articular synovial hyperplasia, joint swelling, cartilage and bone destruction. The in-depth understanding of the role of immune signaling pathway inhibitors provides inspiration for the construction of new and more effective strategy for RA therapy. In this study, by loading methotrexate (MTX) into an acetalated dextran biopolymer, AcDEX, we developed a pH-sensitive, MTX-loaded and molecularly targeted nanodrug MTX@pH-AcDEX NPs) to decrease the toxicity of MTX and simultaneously enhance its therapeutic effect. The resultant MTX@pH-AcDEX NPs showed the spherical morphology and notable pH-responsiveness with high drug loading of 88.32%. As demonstrated in vitro and in vivo, the reduced cytotoxicity of both RAW264.7 cells and LPS-activated RAW264.7 cells treated with MTX@pH-AcDEX NPs was found compared to free MTX. Upon intravenous administration into adjuvant-induced arthritis (AIA) rat model, the nanodrug had potent pharmacokinetic and pharmacodynamic profiles, which can accumulate in RA lesions and release MTX inhibitors for regulating the JAK-STAT pathways. As a result, the MTX@pH-AcDEX NPs achieved the cartilage and bone protective and a better anti-inflammatory effect with negligible systemic toxicity, suggesting the strong potential of safe and effective nanodrug for RA therapy as well as other autoimmune diseases.

Automated summary

This study developed a pH-sensitive nanodrug, MTX@pH-AcDEX NPs, to decrease the toxicity of methotrexate (MTX) and enhance its therapeutic effect for rheumatoid arthritis (RA) treatment. The nanodrug showed notable pH-responsiveness and high drug loading. In vitro and in vivo experiments demonstrated reduced cytotoxicity and better anti-inflammatory effect compared to free MTX. Upon administration in an adjuvant-induced arthritis rat model, the nanodrug exhibited potent pharmacokinetic and pharmacodynamic profiles, accumulating in RA lesions and releasing MTX inhibitors for regulating the JAK-STAT pathways. These findings suggest the strong potential of the nanodrug for safe and effective RA therapy as well as other autoimmune diseases.