A functional tandem between transient receptor potential canonical channels 6 and calcium-dependent chloride channels in human epithelial cells

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• 作者：Johanna Bertrand^a ; Luc Dannhoffer^a ; Fabrice Antigny^a ; Laura Vachel^a ; Christophe Jayle^b ; Clarisse Vandebrouck^a ; Fré ; dé ; ric Becq^a ; Caroline Norez^a ; ^{caroline.norez@univ-poitiers.fr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：BKca channels ; large-conductance Ca2+-activated K+ channels ; CaCC ; Ca2+ dependent Cl&minus ; channel ; CF ; cystic fibrosis ; CFTR ; cystic fibrosis transmembrane conductance regulator ; CFTRinh-172 ; 3-[(3-trifluoromethyl)-phenyl]-5-[(4-carboxyphenyl)methylene]-2-thioxo-4-thiazolidinone ; DAG ; diacylglycerol ; DIDS ; disodium4 ; 4&prime ; -diisothiocyanatostilbene-2 ; 2&prime ; -disulfonate ; DMSO ; dimethylsulfoxide ; OAG ; 1-oleoyl-2-acetyl-sn-glycerol ; siRNA ; small interfering RNA ; TRPC channels ; canonical transi
• 刊名：European Journal of Pharmacology
• 出版年：2015
• 出版时间：15 October 2015
• 年：2015
• 卷：765
• 期：Complete
• 页码：337-345
• 全文大小：1005 K

文摘

TRPC6 plays important human physiological functions, notably in artery and arterioles constriction, in regulation of vascular volume and in bronchial muscle constriction. It is implicated in pulmonary hypertension, cardiovascular disease, and focal segmental glomerulosclerosis and seems to play a role in cancer development. Previously, we identified Guanabenz, an α₂-adrenergic agonist used for hypertension treatment (Wytensin®), as an activator of calcium-dependent chloride channels (CaCC) in human Cystic Fibrosis (CF) nasal epithelial cells by transiently increasing [Ca²⁺]i via an influx of extracellular Ca²⁺. In this study, using assays to measure chloride channel activity, we show that guanabenz is an activator of CaCC in freshly dissociated human bronchial epithelial cells from three CF patients with various genotypes (F508del/F508del, F508del/R1066C, F508del/H1085R). We further characterised the effect of guanabenz and show that it is independent of α-adrenergic receptors, is inhibited by the TRPC family inhibitor SKF-96365 but not by the TRPV family inhibitor ruthenium red. Using western-blotting, Ca²⁺ measurements and iodide efflux assay, we found that TRPC1 siRNA has no effect on guanabenz induced responses whereas TRPC6 siRNA prevented the guanabenz-dependent Ca²⁺ influx and the CaCC-dependent activity stimulated by guanabenz. In conclusion, we show that TRPC6 channel is pivotal for the activation of CaCC by guanabenz through a α₂-adrenergic-independent pathway in human airway epithelial cells. We suggest propose a functional coupling between TRPC6 and CaCC and guanabenz as a potential TRPC6 activator for exploring TRPC6 and CaCC channel functions and corresponding channelopathies.