YM-58483, a selective CRAC channel inhibitor, prevents antigen-induced airway eosinophilia and late phase asthmatic responses via Th2 cytokine inhibition in animal models

T cells play a regulatory role in the pathogenesis of various immune and allergic diseases, including human asthma. Recently, it was reported that a pyrazole derivative, YM-58483 (BTP2), potently inhibits Ca2+ release-activated Ca2+ (CRAC) channels and interleukin (IL)-2 production in T cells. We investigated the effects of YM-58483 on T helper type 2 (Th2) cytokine production in vitro and antigen-induced airway asthmatic responses in vivo. YM-58483 inhibited IL-4 and IL-5 production in a conalbumine-stimulated murine Th2 T cell clone (D10.G4.1), and IL-5 production in phytohemagglutinin-stimulated human whole blood cells with IC50 values comparable to those reported for its CRAC channel inhibition (around 100 nM). YM-58483 inhibited antigen-induced eosinophil infiltration into airways, and decreased IL-4 and cysteinyl-leukotrienes content in inflammatory airways induced in actively sensitized Brown Norway rats. Furthermore, orally administered YM-58483 prevented antigen-induced late phase asthmatic broncoconstriction and eosinophil infiltration in actively sensitized guinea pigs. These data suggest that the inhibition of Ca2+ influx through CRAC channel leads to the prevention of antigen-induced airway inflammation, probably via the inhibition of Th2 cytokine production and inflammatory mediators release. YM-58483 may therefore be useful for treating airway inflammation in bronchial asthma.