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: Nicole Urban, Kerstin Hill, Liming Wang, Wolfgang M Kuebler, Michael Schaefer
• Journal: Cell calcium (Cell Calcium) Vol. 51 Issue 2 Pg. 194-206 (Feb 2012) ISSN: 1532-1991 [Electronic] Netherlands
• PMID: 22280812 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier Ltd. All rights reserved.

Chemical References

• Calcium Channel Blockers
• Small Molecule Libraries
• TRPC Cation Channels
• TRPC3 cation channel
• TRPC6 Cation Channel
• Trpc6 protein, mouse
• Trpc6 protein, rat
• Trpc7 protein, mouse
• Trpc7 protein, rat

Topics

• Animals
• Calcium Channel Blockers (chemistry, pharmacology)
• HEK293 Cells
• Humans
• Hypertension, Pulmonary (drug therapy, genetics, metabolism)
• Hypoxia (complications, genetics, physiopathology)
• Male
• Mice
• Mice, Knockout
• Rats
• Small Molecule Libraries
• TRPC Cation Channels (antagonists & inhibitors, genetics, metabolism)
• TRPC6 Cation Channel
• Vasoconstriction (drug effects)