Expression and regulation of ClC-5 chloride channels: effects of antisense and oxidants

• Published in: American Journal of Physiology: Cell Physiology Vol. 280; no. 6; pp. C1511 - C1520
• Main Authors: Weng, T. X, Mo, L, Hellmich, H. L, Yu, A. S. L, Wood, T, Wills, N. K
• Format: Journal Article
• Language: English
• Published: United States 01.06.2001
• Subjects: Animals; Anions - metabolism; Antisense Elements (Genetics); Biological Transport - physiology; Chloride Channels - genetics; Chloride Channels - metabolism; Chlorides - metabolism; COS Cells; Cyclic AMP - metabolism; Cyclic AMP-Dependent Protein Kinases - antagonists & inhibitors; Cyclic AMP-Dependent Protein Kinases - metabolism; Enzyme Inhibitors - pharmacology; Gene Expression - drug effects; Gene Expression - physiology; Humans; Hydrogen Peroxide - pharmacology; Hydrogen-Ion Concentration; Isoquinolines - pharmacology; Kidney Diseases - metabolism; Membrane Potentials - drug effects; Membrane Potentials - physiology; Oocytes - physiology; Oxidants - pharmacology; Patch-Clamp Techniques; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - metabolism; Sulfonamides; Transfection; Xenopus
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.2001.280.6.C1511

Departments of 1  Physiology and Biophysics, 2  Internal Medicine, and 4  Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston, Texas 77555; and 3  Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02155 Genetic mutations of the Cl channel ClC-5 cause Dent's disease in humans. We recently cloned an amphibian ortholog of Xenopus ClC-5 (xClC-5) from the A6 cell line. We now compare the properties and regulation of ClC-5 currents expressed in mammalian (COS-7) cells and Xenopus oocytes. Whole cell currents in COS-7 cells transfected with xClC-5 cDNA had strong outward rectification, Cl  > I anion sensitivity, and were inhibited at low pH, similar to previous results in oocytes. In oocytes, antisense xClC-5 cRNA injection had no effect on endogenous membrane currents or the heterologous expression of human ClC-5. Activators of cAMP and protein kinase C inhibitors had no significant effects on ClC-5 currents expressed in either COS-7 cells or oocytes, whereas H-89, a cAMP-dependent protein kinase (PKA) inhibitor, and hydrogen peroxide decreased the currents. We conclude that the basic properties of ClC-5 currents were independent of the host cell type used for expression. In addition, ClC-5 channels may be modulated by PKA and reactive oxygen species. Dent's disease; Xenopus oocytes; mammalian COS-7 cells; patch clamp; hydrogen peroxide