Shear stress-induced volume decrease in C11-MDCK cells by BK-α/β4
- 1 September 2010
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Renal Physiology
- Vol. 299 (3), F507-F516
- https://doi.org/10.1152/ajprenal.00222.2010
Abstract
Large-conductance, calcium-activated potassium channels (BK) are expressed in principal cells (PC) and intercalated cells (IC) in mammalian nephrons as BK-α/β1 and BK-α/β4, respectively. IC, which protrude into the lumens of tubules, express substantially more BK than PC despite lacking sufficient Na-K-ATPase to support K secretion. We previously showed in mice that IC exhibit size reduction when experiencing high distal flows induced by a high-K diet. We therefore tested the hypothesis that BK-α/β4 are regulators of IC volume via a shear stress (τ)-induced, calcium-dependent mechanism, resulting in a reduction in intracellular K content. We determined by Western blot and immunocytochemical analysis that C11-Madin-Darby canine kidney cells contained a predominance of BK-α/β4. To determine the role of BK-α/β4 in τ-induced volume reduction, we exposed C11 cells to τ and measured K efflux by flame photometry and cell volume by calcein staining, which changes inversely to cell volume. With 10 dynes/cm2, calcein intensity significantly increased 39% and monovalent cationic content decreased significantly by 37% compared with static conditions. Furthermore, the shear-induced K loss from C11 was abolished by the reduction of extracellular calcium, addition of 5 mM TEA, or BK-β4 small interfering (si) RNA, but not by addition of nontarget siRNA. These results show that BK-α/β4 plays a role in shear-induced K loss from IC, suggesting that BK-α/β4 regulate IC volume during high-flow conditions. Furthermore, these results support the use of C11 cells as in vitro models for studying BK-related functions in IC of the kidney.Keywords
This publication has 52 references indexed in Scilit:
- Intercalated Cell BK-α/β4 Channels Modulate Sodium and Potassium Handling During Potassium AdaptationJournal of the American Society of Nephrology, 2010
- K+ secretion in the rat kidney: Na+ channel-dependent and -independent mechanismsAmerican Journal of Physiology-Renal Physiology, 2009
- Role of BKβ1 in Na+ reabsorption by cortical collecting ducts of Na+-deprived miceAmerican Journal of Physiology-Renal Physiology, 2009
- Hypertension of Kcnmb1 −/− is linked to deficient K secretion and aldosteronismProceedings of the National Academy of Sciences of the United States of America, 2009
- Attenuated, flow-induced ATP release contributes to absence of flow-sensitive, purinergic Cai2+signaling in human ADPKD cyst epithelial cellsAmerican Journal of Physiology-Renal Physiology, 2009
- Cell volume and membrane stretch independently control K+ channel activityThe Journal of Physiology, 2009
- TRPP2 and TRPV4 form a polymodal sensory channel complexThe Journal of cell biology, 2008
- In vitro models of TGF-β-induced fibrosis suitable for high-throughput screening of antifibrotic agentsAmerican Journal of Physiology-Renal Physiology, 2007
- Human ADPKD primary cyst epithelial cells with a novel, single codon deletion in the PKD1 gene exhibit defective ciliary polycystin localization and loss of flow-induced Ca2+ signalingAmerican Journal of Physiology-Renal Physiology, 2007
- Voltage and Ca2+-Activated K+ channel in cultured epithelial cells (MDCK)The Journal of Membrane Biology, 1987