AMSP-30 m as a novel HIF-1α inhibitor attenuates the development and severity of adjuvant-induced arthritis in rats: Impacts on synovial apoptosis, synovial angiogenesis and sonic hedgehog signaling pathway

Growing evidence indicates that synovial hypoxia-inducible factor 1α (HIF-1α) can be as a promising target for RA therapy. We previously reported that AMSP-30 m as a novel HIF-1α inhibitor had potent activities of anticancer metastasis. This study clarified the therapeutic effects of HIF-1α inhibitor AMSP-30 m on adjuvant-induced arthritis (AIA) in rats and explored the possible mechanisms. AMSP-30 m was given intraperitoneally to AIA rats, and its therapeutic effects and anti-inflammatory activity were evaluated. The influences of AMSP-30 m on synovial apoptosis, angiogenesis and sonic hedgehog (Shh) pathway were examined. We found that, accompanied with the inhibition of synovial HIF-1α expression, AMSP-30 m had potent anti-arthritic and anti-inflammatory effects on AIA rats, evidenced by the reduction in paw swelling, arthritis index, histopathological scores, and the production of IL-1β, IL-6, TNF-α in serum and synovial tissues. AMSP-30 m reduced synovial Ki67 expression and increased TUNEL-positive index, indicating its anti-proliferative and pro-apoptotic effects on AIA synovial cells, which was related to reducing Bcl-2 protein level and increasing Bax, cleaved caspase 3 protein levels. Additionally, AMSP-30 m showed anti-angiogenic effects within AIA synovium, indicated by the reduction of synovial VEGF expression and blood vessels number (especially CD31+/αSMA- immature vessels, but not CD31+/αSMA+ mature vessels). Moreover, AMSP-30 m inhibited the activation of synovial Shh pathway, suggested by the reduction of pathway-related proteins, like Shh, Smo, Gli-1, cyclin D1 and c-Myc. Collectively, HIF-1α inhibitor AMSP-30 m exerted potent anti-arthritic effects on AIA rats possibly by promoting synovial apoptosis, reducing synovial angiogenesis and inhibiting Shh pathway.