DBM1285 Suppresses Tumor Necrosis Factor α Production by Blocking p38 Mitogen-Activated Protein Kinase/Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 Signaling Pathway

Tumor necrosis factor alpha (TNF-alpha) is a major inflammatory cytokine that plays an important role in the development of various inflammatory diseases. TNF-alpha has been considered as a potential therapeutic target for the treatment of chronic inflammatory diseases, including rheumatoid arthritis and inflammatory bowel disease. In this study, we report that cyclopropyl-{4-[4-(4-fluorophenyl)-2-piperidin-4-yl-thiazol-5-yl]pyrimidin-2-yl}amine (DBM1285) is a novel inhibitor of TNF-alpha production. DBM1285 concentration-dependently inhibited lipopolysaccharide (LPS)-induced TNF-alpha secretion in various cells of macrophage/monocyte lineage, including mouse bone marrow macrophages, THP-1 cells, andRAW264.7 cells. However, LPS-induced mRNA expression of TNF-alpha was not affected by DBM1285 in these cells. Further studies demonstrated that the inhibitory effect of DBM1285 on TNF-alpha production might be mediated by post-transcriptional regulation through the modulation of the p38 mitogen-activated protein kinase (MAPK)/MAPK-activated protein kinase 2 (MK2) signaling pathway. We also confirmed that DBM1285 directly inhibits p38 MAPK enzymatic activity. In vivo administration of DBM1285 inhibited LPS-induced increase in the plasma level of TNF-alpha in mice. Whole-blood in vivo target inhibition assay also revealed that DBM1285 attenuates p38 MAPK activity after oral administration in mice. Moreover, DBM1285 suppressed zymosan-induced inflammation and adjuvant-induced arthritis in murine models. Collectively, these results suggest that DBM1285 inhibits TNF-alpha production, at least in part, by blocking the p38 MAPK/MK2 pathway. Furthermore, in vivo results suggest that DBM1285 might be a possible therapeutic candidate for the treatment of TNF-alpha-related chronic inflammatory diseases.