Pharmacological inhibition of TRPV2 attenuates phagocytosis and lipopolysaccharide‐induced migration of primary macrophages

Abstract Background and Purpose In macrophages, transient receptor potential vanilloid 2 (TRPV2) channel contributes to various cellular processes such as cytokine production, differentiation, phagocytosis and migration. Due to a lack of selective pharmacological tools, its function in immunological processes is not well understood and the identification of novel and selective TRPV2 modulators is highly desirable. Experimental Approach Novel and selective TRPV2 modulators were identified by screening a compound library using Ca 2+ influx assays with human embryonic kidney 293 (HEK293) cells heterologously expressing rat TRPV2. Hits were further characterized and validated with Ca 2+ influx and electrophysiological assays. Phagocytosis and migration of macrophages were analysed and the contribution of TRPV2 to the generation of Ca 2+ microdomains was studied by total internal reflection fluorescence microscopy (TIRFM). Key Results The compound IV2‐1, a dithiolane derivative (1,3‐dithiolan‐2‐ylidene)‐4‐methyl‐5‐phenylpentan‐2‐one), is a potent inhibitor of heterologously expressed TRPV2 channels (IC 50 = 6.3 ± 0.7 μM) but does not modify TRPV1, TRPV3 or TRPV4 channels. IV2‐1 also inhibits TRPV2‐mediated Ca 2+ influx in macrophages. IV2‐1 inhibits macrophage phagocytosis along with valdecoxib and after siRNA‐mediated knockdown. Moreover, TRPV2 inhibition inhibits lipopolysaccharide‐induced migration of macrophages whereas TRPV2 activation promotes migration. After activation, TRPV2 shapes Ca 2+ microdomains predominantly at the margin of macrophages, which are important cellular regions to promote phagocytosis and migration. Conclusions and Implications IV2‐1 is a novel TRPV2‐selective blocker and underline the role of TRPV2 in macrophage‐mediated phagocytosis and migration. Furthermore, we provide evidence that TRPV2 activation generates Ca 2+ microdomains, which may be involved in phagocytosis and migration of macrophages.