Defective ENaC processing and function in tissue kallikrein-deficient mice.

Details

Serval ID
serval:BIB_97505D167AF9
Type
Article: article from journal or magazin.
Collection
Publications
Title
Defective ENaC processing and function in tissue kallikrein-deficient mice.
Journal
Journal of Biological Chemistry
Author(s)
Picard N., Eladari D., El Moghrabi S., Planès C., Bourgeois S., Houillier P., Wang Q., Burnier M., Deschenes G., Knepper M.A., Meneton P., Chambrey R.
ISSN
0021-9258
Publication state
Published
Issued date
2008
Peer-reviewed
Oui
Volume
283
Number
8
Pages
4602-4611
Language
english
Notes
Publication types: Journal Article ; Research Support, N.I.H., Intramural ; Research Support, Non-U.S. Gov't
Abstract
An inverse relationship exists between urinary tissue kallikrein (TK) excretion and blood pressure in humans and rodents. In the kidney TK is synthesized in large amounts in the connecting tubule and is mainly released into the urinary fluid where its function remains unknown. In the present study mice with no functional gene coding for TK (TK-/-) were used to test whether the enzyme regulates apically expressed sodium transporters. Semiquantitative immunoblotting of the renal cortex revealed an absence of the 70-kDa form of gamma-ENaC in TK-/- mice. Urinary Na+ excretion after amiloride injection was blunted in TK-/- mice, consistent with reduced renal ENaC activity. Amiloride-sensitive transepithelial potential difference in the colon, where TK is also expressed, was decreased in TK-/- mice, whereas amiloride-sensitive alveolar fluid clearance in the lung, where TK is not expressed, was unchanged. In mice lacking the B2 receptor for kinins, the abundance of the 70-kDa form of gamma-ENaC was increased, indicating that its absence in TK-/- mice is not kinin-mediated. Incubation of membrane proteins from renal cortex of TK-/- mice with TK resulted in the appearance of the 70-kDa band of the gamma-ENaC, indicating that TK was able to promote gamma-ENaC cleavage in vitro. Finally, in mouse cortical collecting ducts isolated and microperfused in vitro, the addition of TK in the luminal fluid increased significantly intracellular Na+ concentration, consistent with an activation of the luminal entry of the cation. The results demonstrate that TK, like several other proteases, can activate ENaC in the kidney and the colon.
Keywords
Amiloride/pharmacology, Animals, Colon/cytology, Colon/enzymology, Epithelial Sodium Channel/metabolism, Humans, Ion Transport/drug effects, Ion Transport/physiology, Kidney Cortex/cytology, Kidney Cortex/enzymology, Kidney Tubules, Collecting/cytology, Kidney Tubules, Collecting/enzymology, Membrane Potentials/drug effects, Membrane Potentials/physiology, Mice, Protein Processing, Post-Translational/drug effects, Protein Processing, Post-Translational/physiology, Pulmonary Alveoli/cytology, Pulmonary Alveoli/enzymology, Receptor, Bradykinin B2/genetics, Receptor, Bradykinin B2/metabolism, Sodium/metabolism, Sodium Channel Blockers/pharmacology, Tissue Kallikreins/genetics, Tissue Kallikreins/metabolism
Pubmed
Web of science
Open Access
Yes
Create date
17/07/2008 9:52
Last modification date
20/08/2019 14:59
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