TRPM4 regulates migration of mast cells in mice.

We demonstrate here that the transient receptor potential melastatin subfamily channel, TRPM4, controls migration of bone marrow-derived mast cells (BMMCs), triggered by dinitrophenylated human serum albumin (DNP-HSA) or stem cell factor (SCF). Wild-type BMMCs migrate after stimulation with DNP-HSA or SCF whereas both stimuli do not induce migration in BMMCs derived from TRPM4 knockout mice (trpm4(-/-)). Mast cell migration is a Ca(2+)-dependent process, and TRPM4 likely controls this process by setting the intracellular Ca(2+) level upon cell stimulation. Cell migration depends on filamentous actin (F-actin) rearrangement, since pretreatment with cytochalasin B, an inhibitor of F-actin formation, prevented both DNP-HSA- and SCF-induced migration in wild-type BMMC. Immunocytochemical experiments using fluorescence-conjugated phalloidin demonstrate a reduced level of F-actin formation in DNP-HSA-stimulated BMMCs from trpm4(-/-) mice. Thus, our results suggest that TRPM4 is critically involved in migration of BMMCs by regulation of Ca(2+)-dependent actin cytoskeleton rearrangements.