title: The contribution of TRPV4-mediated calcium signaling to calcium homeostasis in endothelial cells.
abstract: A large variety of cation transport systems are involved in the regulation of calcium homeostasis in endothelial cells. The focus of the present study is to determine the contribution of nonselective cation channels from the TRP (transient receptor potential) family to cellular calcium homeostasis of porcine aortic endothelial cells (PAEC). One member of the TRPV (vanniloid) subfamily, TRPV4, has previously been shown to be involved in cation transport induced by a large variety of stimulations including osmolarity, temperature, mechanical stress, and phosphorylation. Here, we demonstrate the existence of several TRP proteins, including TRPV4, in PAEC using RT-PCR. To test whether this channel is functional, we performed FURA-2 calcium measurements and whole-cell patch-clamp experiments. We observed the induction of large calcium signals following mechanical stress, altered extracellular temperature, and the selective TRPV4 activator 4-alpha -PDD. These effects were diminished in the presence of the TRPV4 inhibitor miconazole, suggesting the involvement of this channel in mediating endothelial calcium signals. The large amounts of transported calcium and the short signaling ways suggest a potentially important role of this channel in many physiological processes.
authors.affiliation: Institute of Pharmaceutical Sciences, Pharmacology and Toxicology, Karl-Franzens-University of Graz, Universitaetsplatz 2, Graz, Austria.
authors.forename: Roland
authors.initials: R
authors.lastname: Fian
authors.forename: Erik
authors.initials: E
authors.lastname: Grasser
authors.forename: Fritz
authors.initials: F
authors.lastname: Treiber
authors.forename: Renate
authors.initials: R
authors.lastname: Schmidt
authors.forename: Petra
authors.initials: P
authors.lastname: Niederl
authors.forename: Christian
authors.initials: C
authors.lastname: Rosker
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006706:Homeostasis / Q000187:drug effects; D008825:Miconazole / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology; D013552:Swine / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000378:metabolism*; D013696:Temperature
chemical_list: D010703:Phorbol Esters; D050916:TRPV Cation Channels; C008876:phorbol-12,13-didecanoate; D008825:Miconazole; D002118:Calcium