Document Detail

Shear stress-induced volume decrease in C11-MDCK cells by BK-alpha/beta4.
MedLine Citation:
PMID:  20576683     Owner:  NLM     Status:  MEDLINE    
Large-conductance, calcium-activated potassium channels (BK) are expressed in principal cells (PC) and intercalated cells (IC) in mammalian nephrons as BK-alpha/beta1 and BK-alpha/beta4, 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-alpha/beta4 are regulators of IC volume via a shear stress (tau)-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-alpha/beta4. To determine the role of BK-alpha/beta4 in tau-induced volume reduction, we exposed C11 cells to tau and measured K efflux by flame photometry and cell volume by calcein staining, which changes inversely to cell volume. With 10 dynes/cm(2), 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-beta4 small interfering (si) RNA, but not by addition of nontarget siRNA. These results show that BK-alpha/beta4 plays a role in shear-induced K loss from IC, suggesting that BK-alpha/beta4 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.
J David Holtzclaw; Liping Liu; P Richard Grimm; Steven C Sansom
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-06-24
Journal Detail:
Title:  American journal of physiology. Renal physiology     Volume:  299     ISSN:  1522-1466     ISO Abbreviation:  Am. J. Physiol. Renal Physiol.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-03     Completed Date:  2010-09-24     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  100901990     Medline TA:  Am J Physiol Renal Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  F507-16     Citation Subset:  IM    
Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, 68198-5850, USA.
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MeSH Terms
Calcium / metabolism
Cell Line
Cell Size*
Kidney / cytology*,  metabolism*
Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / metabolism*
Large-Conductance Calcium-Activated Potassium Channel beta Subunits / metabolism*
Models, Animal
Potassium / metabolism
Potassium Channel Blockers / pharmacology
RNA, Small Interfering / pharmacology
Stress, Mechanical*
Tetraethylammonium / pharmacology
Grant Support
3R01 DK071014-03S1/DK/NIDDK NIH HHS; R01 DK071014/DK/NIDDK NIH HHS; R01 DK071014-05/DK/NIDDK NIH HHS; R01 DK73070/DK/NIDDK NIH HHS; U24-NS-050606/NS/NINDS NIH HHS
Reg. No./Substance:
0/Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; 0/Large-Conductance Calcium-Activated Potassium Channel beta Subunits; 0/Potassium Channel Blockers; 0/RNA, Small Interfering; 66-40-0/Tetraethylammonium; 7440-09-7/Potassium; 7440-70-2/Calcium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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