Dataset Information

Human cystic fibrosis airway epithelia have reduced Cl- conductance but not increased Na+ conductance.

ABSTRACT: Loss of cystic fibrosis transmembrane conductance regulator (CFTR) anion channel function causes cystic fibrosis (CF) lung disease. CFTR is expressed in airway epithelia, but how CF alters electrolyte transport across airway epithelia has remained uncertain. Recent studies of a porcine model showed that in vivo, excised, and cultured CFTR(-/-) and CFTR(?F508/?F508) airway epithelia lacked anion conductance, and they did not hyperabsorb Na(+). Therefore, we asked whether Cl(-) and Na(+) conductances were altered in human CF airway epithelia. We studied differentiated primary cultures of tracheal/bronchial epithelia and found that transepithelial conductance (Gt) under basal conditions and the cAMP-stimulated increase in Gt were markedly attenuated in CF epithelia compared with non-CF epithelia. These data reflect loss of the CFTR anion conductance. In CF and non-CF epithelia, the Na(+) channel inhibitor amiloride produced similar reductions in Gt and Na(+) absorption, indicating that Na(+) conductance in CF epithelia did not exceed that in non-CF epithelia. Consistent with previous reports, adding amiloride caused greater reductions in transepithelial voltage and short-circuit current in CF epithelia than in non-CF epithelia; these changes are attributed to loss of a Cl(-) conductance. These results indicate that Na(+) conductance was not increased in these cultured CF tracheal/bronchial epithelia and point to loss of anion transport as key to airway epithelial dysfunction in CF.

SUBMITTER: Itani OA

PROVIDER: S-EPMC3121869 | biostudies-other | 2011 Jun

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Human cystic fibrosis airway epithelia have reduced Cl- conductance but not increased Na+ conductance.

Itani Omar A OA Chen Jeng-Haur JH Karp Philip H PH Ernst Sarah S Keshavjee Shaf S Parekh Kalpaj K Klesney-Tait Julia J Zabner Joseph J Welsh Michael J MJ

Proceedings of the National Academy of Sciences of the United States of America 20110606 25

Loss of cystic fibrosis transmembrane conductance regulator (CFTR) anion channel function causes cystic fibrosis (CF) lung disease. CFTR is expressed in airway epithelia, but how CF alters electrolyte transport across airway epithelia has remained uncertain. Recent studies of a porcine model showed that in vivo, excised, and cultured CFTR(-/-) and CFTR(ΔF508/ΔF508) airway epithelia lacked anion conductance, and they did not hyperabsorb Na(+). Therefore, we asked whether Cl(-) and Na(+) conductan ...[more]

PMID: 21646513

Similar Datasets

Project description:Key pointsCl- and HCO3 - had similar paracellular permeabilities in human airway epithelia. PCl /PNa of airway epithelia was unaltered by pH 7.4 vs. pH 6.0 solutions. Under basal conditions, calculated paracellular HCO3 - flux was secretory. Cytokines that increased airway surface liquid pH decreased or reversed paracellular HCO3 - flux. HCO3 - flux through the paracellular pathway may counterbalance effects of cellular H+ and HCO3 - secretion.AbstractAirway epithelia control the pH of airway surface liquid (ASL), thereby optimizing respiratory defences. Active H+ and HCO3 - secretion by airway epithelial cells produce an ASL that is acidic compared with the interstitial space. The paracellular pathway could provide a route for passive HCO3 - flux that also modifies ASL pH. However, there is limited information about paracellular HCO3 - flux, and it remains uncertain whether an acidic pH produced by loss of cystic fibrosis transmembrane conductance regulator anion channels or proinflammatory cytokines might alter the paracellular pathway function. To investigate paracellular HCO3 - transport, we studied differentiated primary cultures of human cystic fibrosis (CF) and non-CF airway epithelia. The paracellular pathway was pH-insensitive at pH 6.0 vs. pH 7.4 and was equally permeable to Cl- and HCO3 - . Under basal conditions at pH ∼6.6, calculated paracellular HCO3 - flux was weakly secretory. Treating epithelia with IL-17 plus TNFα alkalinized ASL pH to ∼7.0, increased paracellular HCO3 - permeability, and paracellular HCO3 - flux was negligible. Applying IL-13 increased ASL pH to ∼7.4 without altering paracellular HCO3 - permeability, and calculated paracellular HCO3 - flux was absorptive. These results suggest that HCO3 - flux through the paracellular pathway counterbalances, in part, changes in the ASL pH produced via cellular mechanisms. As the pH of ASL increases towards that of basolateral liquid, paracellular HCO3 - flux becomes absorptive, tempering the alkaline pH generated by transcellular HCO3 - secretion.

Dataset Information

Human cystic fibrosis airway epithelia have reduced Cl- conductance but not increased Na+ conductance.

Publications

Human cystic fibrosis airway epithelia have reduced Cl- conductance but not increased Na+ conductance.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets