Bone marrow mesenchymal stem cells relieve rheumatoid arthritis by blocking JAK/STAT and TLR-4/NF-κB pathways

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by synovial inflammation and joint destruction. Bone marrow mesenchymal stem cells (BMSCs) have shown therapeutic potential in RA, but the underlying mechanisms remain poorly understood.

To investigate the effects of BMSCs on human RA fibroblast-like synovial MH7A cells and complete Freund's adjuvant (CFA)-induced arthritis in rats and to explore the involvement of the JAK/STAT and TLR-4/NF-κB signaling pathways.

BMSCs were isolated and co-cultured with MH7A cells. CFA-induced arthritis rat models were established. MH7A cell viability, inflammatory cytokine levels, paw withdrawal thermal latency (PWTL), gait parameters and the expression of JAK/STAT and TLR-4/NF-κB pathway-related genes and proteins were assessed.

In-vitro, BMSC co-culture significantly inhibited MH7A cell viability and reduced TNF-α, IL-6 and IL-8 levels. BMSC treatment also downregulated the expression of JAK2, p-JAK2, STAT3, p-STAT3, TLR4, P65 and p-P65 in MH7A cells. In-vivo, BMSC administration improved PWTL and gait parameters, reduced serum inflammatory cytokine levels and suppressed the expression of JAK/STAT and TLR-4/NF-κB pathway components in synovial tissues of CFA-induced arthritic rats.

BMSCs alleviate RA by inhibiting inflammatory responses in vitro and in vivo and the underlying mechanism may involve blockade of the JAK/STAT and TLR-4/NF-κB signaling pathways.