The alpha-subunit of the epithelial sodium channel is an aldosterone-induced transcript in mammalian collecting ducts, and this transcriptional response is mediated via distinct cis-elements in the 5'-flanking region of the gene

V E Mick; O A Itani; R W Loftus; R F Husted; T J Schmidt; C P Thomas

doi:10.1210/mend.15.4.0620

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The alpha-subunit of the epithelial sodium channel is an aldosterone-induced transcript in mammalian collecting ducts, and this transcriptional response is mediated via distinct cis-elements in the 5'-flanking region of the gene

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The alpha-subunit of the epithelial sodium channel is an aldosterone-induced transcript in mammalian collecting ducts, and this transcriptional response is mediated via distinct cis-elements in the 5'-flanking region of the gene

V E Mick, O A Itani, R W Loftus, R F Husted, T J Schmidt and C P Thomas

Molecular endocrinology (Baltimore, Md.), Vol.15(4), pp.575-588

04/2001

DOI: 10.1210/mend.15.4.0620

PMID: 11266509

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https://doi.org/10.1210/me.15.4.575View

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Abstract

Aldosterone stimulates Na(+) reabsorption in the collecting ducts by increasing the activity of the epithelial sodium channel, ENaC. Systemic administration of aldosterone increases alpha ENaC mRNA expression in mammalian kidney, suggesting that the alpha ENaC gene is a target for aldosterone action in the distal nephron. To determine whether aldosterone increases alpha ENaC gene transcription, a portion of the alpha ENaC 5'- flanking region coupled to luciferase was transfected into MDCK-C7 cells, a collecting duct cell line with aldosterone-stimulated Na(+) transport. Both dexamethasone and aldosterone stimulated alpha ENaC-coupled reporter gene activity via the glucocorticoid receptor (GR), and this response correlated with the effect of these hormones on endogenous alpha ENaC expression. The aldosterone-stimulated alpha ENaC expression was blocked by actinomycin D, and aldosterone had no effect on alpha ENaC mRNA decay, confirming a transcriptional effect. In HT-29 cells, a GR/mineralocorticoid receptor (MR)-deficient colonic cell line with constitutive alpha ENaC expression, cotransfection with GR or MR restored aldosterone-stimulated alpha ENaC gene transcription, although aldosterone had a functional preference for MR. Analysis of deletion constructs confirmed that a single imperfect glucocorticoid response element (GRE) is necessary and sufficient to confer the aldosterone responsiveness to the alpha ENaC gene promoter in MDCK-C7 and HT-29 cells. These results confirm that alpha ENaC is an aldosterone-induced transcript in the collecting duct and delineates the molecular mechanism for this effect.

Protein Subunits

Receptors, Glucocorticoid - antagonists & inhibitors

Receptors, Mineralocorticoid - metabolism

Humans

Regulatory Sequences, Nucleic Acid

Molecular Sequence Data

Receptors, Glucocorticoid - metabolism

Kidney Tubules, Collecting - cytology

Epithelial Sodium Channels

Receptors, Mineralocorticoid - drug effects

Aldosterone - metabolism

Dexamethasone - pharmacology

Base Sequence

Cloning, Molecular

Sodium Channels - metabolism

Transcription, Genetic

Receptors, Glucocorticoid - drug effects

Binding Sites

Gonanes - pharmacology

Promoter Regions, Genetic

Kidney Tubules, Collecting - physiology

Response Elements

Cells, Cultured

Aldosterone - pharmacology

Animals

Dogs

Mice

Sodium Channels - genetics

Mifepristone - pharmacology

Dactinomycin - pharmacology

Details

Title: Subtitle: The alpha-subunit of the epithelial sodium channel is an aldosterone-induced transcript in mammalian collecting ducts, and this transcriptional response is mediated via distinct cis-elements in the 5'-flanking region of the gene
Creators: V E Mick - Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
O A Itani
R W Loftus
R F Husted
T J Schmidt
C P Thomas
Resource Type: Journal article
Publication Details: Molecular endocrinology (Baltimore, Md.), Vol.15(4), pp.575-588
Publisher: United States
DOI: 10.1210/mend.15.4.0620
PMID: 11266509
ISSN: 0888-8809
eISSN: 1944-9917
Grant note: R01 DK054348 / NIDDK NIH HHS DK-54348 / NIDDK NIH HHS
Alternative title: The α-Subunit of the Epithelial Sodium Channel Is an Aldosterone-Induced Transcript in Mammalian Collecting Ducts, and This Transcriptional Response Is Mediated via Distinct cis-Elements in the 5′-Flanking Region of the Gene
Language: English
Date published: 04/2001
Academic Unit: Molecular Physiology and Biophysics; Stead Family Department of Pediatrics; Anesthesia; Obstetrics and Gynecology; Nephrology; Internal Medicine
Record Identifier: 9983986083602771

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