Expression and function of cystic fibrosis transmembrane conductance regulator in rat intrapulmonary arteries

Abstract

The cystic fibrosis transmembrane conductance regulator (CFTR) gene encodes a cyclic adenosine monophosphate (cAMP)-dependent chloride channel located mainly at the apical membrane of epithelial cells. In myocytes of pulmonary arteries, numerous chloride channels have been identified and described, but not the CFTR. Thus the presence and function of the CFTR was investigated in rat intrapulmonary arteries.CFTR expression, localisation and function were analysed in cultured smooth muscle cells using Reverse transcriptase (RT)-PCR and immunoprecipitation followed by protein kinase A phosphorylation, immunolocalisation and an iodide efflux assay, respectively. The role of the CFTR in pulmonary vasoreactivity was determined in arterial rings using an organ bath system.RT-PCR and immunoprecipitation analyses, as well as the immunolocalisation study, revealed the expression of CFTR gene transcripts and protein. The iodide efflux assay showed the existence of functional cAMP-, calcium-and volume-dependent chloride channels. Furthermore, the following effects were found: 1) inhibition of forskolin/genistein-activated iodide efflux by glibenclamide, diphenylamine-2-carboxylic acid and CFTR-specific inhibitor (CFTRinh)-172; 2) activation of iodide efflux by the benzoquinolizinium derivative CFTR activators MPB-07 and MPB-91; and 3) inhibition of MPB-dependent efflux by CFTRinh-172. Finally, CFTR activators induced concentration-dependent vasorelaxation in rings preconstricted with phenylephrine, in the presence or absence of endothelium.The present results are the first to reveal functional cyclic adenosine monophosphate-regulated cystic fibrosis transmembrane conductance regulator contributing to endothelium-independent vasorelaxation in rat intrapulmonary arterial myocytes.

Pulmonary vascular dysfunction in end-stage cystic fibrosis: role of NF-κB and endothelin-1

“…Alternative hypothesis could be that genistein is a strong CFTR potentiator [36]. The latter has recently been demonstrated to be markedly involved in vasodilation [37][38][39]. In addition, genistein could act through its wide enhancing effects on the transcription of vasodilative proteins, some of them involving different tyrosine kinase activities.…”

CFTR Regulation of Intracellular pH and Ceramides Is Required for Lung Endothelial Cell Apoptosis

“…Although the presence of CFTR in cells other than epithelium is now well documented (2,(26)(27)(28), its role in these cellular compartments, particularly in the endothelium, is not well known. Our work contributes to the understanding of the role of CFTR in lung endothelial cell viability.…”

CF airway smooth muscle transcriptome reveals a role for PYK2

“…Second, acute CFTR potentiation, in people with CF and the G551D-CFTR mutation, corrected smooth muscle abnormalities with improvements in airway distensibility and vascular tone (2). Finally, investigations by our group and others have shown that loss or inhibition of CFTR function in animal models can affect smooth muscle tone (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). Collectively, these studies indicate that the asthma-like symptoms experienced by individuals with CF could be, in part, due to functional loss of CFTR.…”