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The Role of TRP Channels in Mechanotransduction of HUVECYuki Katanosaka, Tomohiko Suemori, Keiji Naruse. Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University.Human umbilical vein endothelial cells (HUVEC) at the interface between the bloodstream and the vessel wall are continuously subjected to mechanical stimulations in vivo, such as shear stress, hydrostatic pressure and stretch, and it is widely recognized that they are playing an important physiological role in cardiovascular system. In response to stretch, we reported that intracellular Ca2+ increased transiently through the activation of mechanosensitive (MS) cation channel in HUVEC. However, the molecular entities that form the MS cation channel in the cell remain unknown. Recent papers report some members of the transient receptor potential (TRP) channels have been suggested as one of components of MS channels. To identify the molecules forming MS in HUVEC, we investigated the role of TRP channels in this cell. We observed the expression of several isoforms of TRP channels in HUVEC using immunoblotting method. Among these channels, hTRPV2 was localized very close to the mesh-work structure of the cortical-actin in semi-intact plane membrane of HUVEC. It was noteworthy that stretch-induced change in [Ca2+]i measured by fura2 was significantly higher in hTRPV2 transfected HUVEC and that it was significantly inhibited by the treatment of morphorino oligo against hTRPV2. From these results, we discuss molecular complex that forms MS channel, above all the possible involvement of TRPV2 in HUVEC. [J Physiol Sci. 2007;57 Suppl:S222]
