Rheumatoid arthritis (RA) is systemic autoimmune arthritis that causes joint inflammation and destruction. Accumulating evidence has shown that inhibitors of class I histone deacetylases (HDACs) (i.e., HDAC1, 2, 3, and 8) are potential therapeutic candidates as targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs). Nevertheless, the inhibition of class I HDACs has severe adverse effects because of their broad spectrum. We evaluated the therapeutic effect of a novel selective HDAC1 inhibitor TTA03-107 for collagen-induced arthritis (CIA) and collagen antibody-induced arthritis (CAIA) models in mice. We also examined the effect of TTA03-107 in bone marrow-derived macrophages (BMDMs) and T helper 17 (Th17) cells in vitro. Here, we delineate that TTA03-107 reduced the severity of autoimmune arthritis without obvious adverse effects in CIA and CAIA models. Moreover, TTA03-107 suppressed the production of inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-17A, in serum and joint tissue. In vitro treatment of BMDMs with TTA03-107 dampened the M1 differentiation and inflammatory cytokine production. TTA03-107 also suppressed the differentiation of Th17 cells. These results demonstrate that TTA03-107 can attenuate the development of arthritis in experimental RA models by inhibiting the differentiation and activation of macrophages and Th17 cells. Therefore, TTA03-107 is a potential tsDMARD candidate.
Keywords: T helper 17 cell; collagen antibody-induced arthritis; collagen-induced arthritis; histone deacetylase 1 inhibitor; macrophage; rheumatoid arthritis.