Journal article
Alveolar Epithelial Ion and Fluid Transport: Glucocorticoid-stimulated lung epithelial Na+ transport is associated with regulated ENaC and sgk1 expression
AJP - Lung Cellular and Molecular Physiology, Vol.282(4), pp.631-L641
04/01/2002
DOI: 10.1152/ajplung.00085.2001
PMID: 11880287
Abstract
H441 cells, a bronchiolar epithelial cell line, develop a glucocorticoid-regulated amiloride-sensitive Na+ transport pathway on permeable supports (R. Sayegh, S. D. Auerbach, X. Li, R. Loftus, R. Husted, J. B. Stokes, and C. P. Thomas.J Biol Chem 274: 12431–12437, 1999). To understand its molecular basis, we examined the effect of glucocorticoids (GC) on epithelial Na+ channel (ENaC)-α, -β, and -γ andsgk1 expression and determined the biophysical properties of Na+ channels in these cells. GC stimulated the expression of ENac-α, -β, and -γ and sgk1 mRNA, with the first effect seen by 1 h. These effects were abolished by actinomycin D, but not by cycloheximide, indicating a direct stimulatory effect on ENaC and sgk1 mRNA synthesis. The GC effect on transcription of ENaC-α mRNA was accompanied by a significant increase in ENaC-α protein levels. GC also stimulated ENaC-α, -β, and -γ andsgk1 mRNA expression in A549 cells, an alveolar type II cell line. To determine the biophysical properties of the Na+channel, single-channel currents were recorded from cell-attached H441 membranes. An Na+-selective channel with slow kinetics and a slope conductance of 10.8 pS was noted, properties similar to ENaC-α, -β, and -γ expressed in Xenopus laevis oocytes. These experiments indicate that amiloride-sensitive Na+ transport is mediated through classic ENaC channels in human lung epithelia and that GC-regulated Na+ transport is accompanied by increased transcription of each of the component subunits and sgk1.
Details
- Title: Subtitle
- Alveolar Epithelial Ion and Fluid Transport: Glucocorticoid-stimulated lung epithelial Na+ transport is associated with regulated ENaC and sgk1 expression
- Creators
- Omar A ItaniScott D AuerbachRussell F HustedKenneth A VolkShana AgeloffMark A KnepperJohn B StokesChristie P Thomas
- Resource Type
- Journal article
- Publication Details
- AJP - Lung Cellular and Molecular Physiology, Vol.282(4), pp.631-L641
- DOI
- 10.1152/ajplung.00085.2001
- PMID
- 11880287
- ISSN
- 1040-0605
- eISSN
- 1522-1504
- Language
- English
- Date published
- 04/01/2002
- Academic Unit
- Stead Family Department of Pediatrics; Obstetrics and Gynecology; Nephrology; Internal Medicine
- Record Identifier
- 9983986368502771
Metrics
27 Record Views