title: Effect of hypoxia on TRPV1 and TRPV4 channels in rat pulmonary arterial smooth muscle cells.
abstract: Transient receptor potential (TRP) channels of the vanilloid subfamily, mainly TRPV1 and TRPV4, are expressed in pulmonary artery smooth muscle cells (PASMC) and implicated in the remodeling of pulmonary artery, a landmark of pulmonary hypertension (PH). Among a variety of PH subtypes, PH of group 3 are mostly related to a prolonged hypoxia exposure occurring in a variety of chronic lung diseases. In the present study, we thus investigated the role of hypoxia on TRPV1 and TRPV4 channels independently of the increased pulmonary arterial pressure that occurs during PH. We isolated PASMC from normoxic rat and cultured these cells under in vitro hypoxia. Using microspectrofluorimetry and the patch-clamp technique, we showed that hypoxia (1 % O2 for 48 h) significantly increased stretch- and TRPV4-induced calcium responses. qRT-PCR, Western blotting, and immunostaining experiments revealed that the expression of TRPV1 and TRPV4 was not enhanced under hypoxic conditions, but we observed a membrane translocation of TRPV1. Furthermore, hypoxia induced a reorganization of the F-actin cytoskeleton, the tubulin, and intermediate filament networks (immunostaining experiments), associated with an enhanced TRPV1- and TRPV4-induced migratory response (wound-healing assay). Finally, as assessed by immunostaining, exposure to in vitro hypoxia elicited a significant increase in NFATc4 nuclear localization. Cyclosporin A and BAPTA-AM inhibited NFATc4 translocation, indicating the activation of the Ca(2+)/calcineurin/NFAT pathway. In conclusion, these data point out the effect of hypoxia on TRPV1 and TRPV4 channels in rat PASMC, suggesting that these channels can act as direct signal transducers in the pathophysiology of PH.
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Thibaud
authors: T
authors: Parpaite
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Guillaume
authors: G
authors: Cardouat
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Marthe
authors: M
authors: Mauroux
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Jennifer
authors: J
authors: Gillibert-Duplantier
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Paul
authors: P
authors: Robillard
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Jean-François
authors: JF
authors: Quignard
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Roger
authors: R
authors: Marthan
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France.
authors: Jean-Pierre
authors: JP
authors: Savineau
authors: Univ. Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France. thomas.ducret@u-bordeaux.fr.|INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, F-33000, Bordeaux, France. thomas.ducret@u-bordeaux.fr.|Centre de Recherche Cardio-Thoracique de Bordeaux, INSERM U1045, Université de Bordeaux, 146 rue Léo-Saignat (case 13), F-33076, Bordeaux cedex, France. thomas.ducret@u-bordeaux.fr.
authors: Thomas
authors: T
authors: Ducret
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D050778:NFATC Transcription Factors / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D021381:Protein Transport; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D050916:TRPV Cation Channels / Q000378:metabolism*
chemical_list: D050778:NFATC Transcription Factors; D009419:Nerve Tissue Proteins; C477593:Nfatc4 protein, rat; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; C486577:Trpv4 protein, rat; D010100:Oxygen
keywords: Calcium; Hypoxia; Migration; Stretch-activated channels; TRP channels; Vascular smooth muscle