Acetazolamide as an aquaporin 1 inhibitor mitigates rheumatoid arthritis by reducing angiogenesis via the modulation of the FAK-PI3K/Akt signaling pathway.

Synovial angiogenesis worsens the course of rheumatoid arthritis (RA) by driving pannus formation and chronic inflammation, implying anti-angiogenesis as a possible treatment strategy. Aquaporin 1 (AQP1) is a promising target for RA, and its inhibitor acetazolamide (AZ) exerts anti-arthritic effects in RA animal models. Particularly, AZ is effective in inhibiting angiogenesis in multiple illnesses. However, AZ's impacts on angiogenesis in the RA context and its underlying mechanisms are unclear. This study investigated AZ's influences on migration, invasion, chemotaxis, and tube formation in human umbilical vein endothelial cells (HUVECs). Moreover, AZ's anti-angiogenic effects were examined in zebrafish and adjuvant-induced arthritis (AIA) rat synovium. The involvement of the focal adhesion kinase (FAK)-PI3K/AKT axis was also studied. Herein, AZ inhibited VEGF-induced migration and invasion in HUVECs and reduced their chemotactic migration toward RA fibroblast-like synoviocytes (FLS)-released chemoattractants. AZ inhibited HUVEC tube formation in response to the conditioned medium of RA FLS and reduced subintestinal vessel growth in zebrafish, highlighting its anti-angiogenic effects in vitro and in vivo in zebrafish. In AIA rats, AZ mitigated the disease severity and attenuated synovial angiogenesis, as evidenced by decreased numbers of blood vessels and CD31-positive cells. Mechanistically, AZ disrupted the AQP1-FAK interaction, resulting in FAK destabilization and degradation, which was supported by the abrogation of AZ's effects on HUVECs after FAK overexpression. Expectedly, AZ inactivated the FAK-PI3K/Akt pathway in VEGF-induced HUVECs and AIA rat synovium. Collectively, AZ as an AQP1 inhibitor showed anti-rheumatoid effects by reducing angiogenesis through modulation of the FAK-PI3K/AKT pathway.