title: Novel pharmacological TRPC inhibitors block hypoxia-induced vasoconstriction.
abstract: The Ca(2+)-permeable, nonselective cation channel TRPC6 is gated via phospholipase C-activating receptors and has recently been implicated in hypoxia-induced pulmonary vasoconstriction (HPV), idiopathic pulmonary hypertension and focal segmental glomerulosclerosis (FSGS). Therefore, TRPC6 is a promising target for pharmacological interference. To identify and develop TRPC6-blocking compounds, we screened the Chembionet library, a collection of 16,671 chemically diverse drug-like compounds, for biological activity to prevent the 1-oleoyl-2-acetyl-sn-glycerol-triggered Ca(2+) influx in a stably transfected HEK(TRPC6-YFP) cell line. Hits were validated and characterised by fluorometric and electrophysiological methods. Six compounds displayed inhibitory potency at low micromolar concentrations, lack of cytotoxicity and blocked the receptor-dependent mode of TRPC6 activation. The specificity was tested towards closely (TRPC3 and TRPC7) and more distantly related TRP channels. One of the compounds, 8009-5364, displayed a 2.5-fold TRPC6-selectivity compared to TRPC3, and almost no inhibition of TRPC7 or the other TRP channels tested. Block of native TRPC3/6-like responses was confirmed in dissociated pulmonary artery smooth muscle cells. Two non-polar blockers effectively suppressed the HPV responses in the perfused mouse lung model. We conclude that pharmacological targeting of TRPC6 is feasible and provide a promising concept to treat pulmonary diseases that are characterised by excessive hypoxic vasoconstriction.
authors.affiliation: Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstrasse 16-18, Leipzig, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Urban
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hill
authors.forename: Liming
authors.initials: L
authors.lastname: Wang
authors.forename: Wolfgang M
authors.initials: WM
authors.lastname: Kuebler
authors.forename: Michael
authors.initials: M
authors.lastname: Schaefer
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000737:chemistry / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D000860:Hypoxia / Q000150:complications / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D051381:Rats; D054852:Small Molecule Libraries; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000074287:TRPC6 Cation Channel; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D002121:Calcium Channel Blockers; D054852:Small Molecule Libraries; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D000074287:TRPC6 Cation Channel; C492146:Trpc6 protein, mouse; C492145:Trpc6 protein, rat; C498502:Trpc7 protein, mouse; C498498:Trpc7 protein, rat