| Ion transport in a human lens epithelial cell line exposed to hyposmotic and apoptotic stress. | |
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MedLine Citation:
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PMID: 20049853 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Membrane transport changes in human lens epithelial (HLE-B3) cells under hyposmotic and apoptotic stress were compared. Cell potassium content, K(i), uptake of the K congener rubidium, Rb(i), and water content were measured after hyposmotic stress induced by hypotonicity, and apoptotic stress by the protein-kinase inhibitor staurosporine (STP). Cell water increased in hyposmotic (150 mOsm) as compared to isosmotic (300 mOsm) balanced salt solution (BSS) by >2-fold at 5 min and decreased within 15 min to baseline values accompanied by a 40% K(i) loss commensurate with cell swelling and subsequent cell shrinkage likely due to regulatory volume decrease (RVD). Loss of K(i), and accompanying water, and Rb(i) uptake in hyposmotic BSS were prevented by clotrimazole (CTZ) suggesting water shifts associated with K and Rb flux via intermediate conductance K (IK) channels, also detected at the mRNA and protein level. In contrast, 2 h after 2 microM STP exposure, the cells lost approximately 40% water and approximately 60% K(i), respectively, consistent with apoptotic volume decrease (AVD). Indeed, water and K(i) loss was at least fivefold greater after hyposmotic than after apoptotic stress. High extracellular K and 2 mM 4-aminopyridine (4-AP) but not CTZ significantly reduced apoptosis. Annexin labeling phosphatidylserine (PS) at 15 min suggested loss of lipid asymmetry. Quantitative PCR revealed significant IK channel expression during prolonged hyposmotic stress. Results suggest in HLE-B3 cells, IK channels likely partook in and were down regulated after RVD, whereas pro-apoptotic STP-activation of 4-AP-sensitive voltage-gated K channels preceded or accompanied PS externalization before subsequent apoptosis. |
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Authors:
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Ameet A Chimote; Norma C Adragna; Peter K Lauf |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of cellular physiology Volume: 223 ISSN: 1097-4652 ISO Abbreviation: J. Cell. Physiol. Publication Date: 2010 Apr |
Date Detail:
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Created Date: 2010-02-01 Completed Date: 2010-03-08 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0050222 Medline TA: J Cell Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 110-22 Citation Subset: IM |
Copyright Information:
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J. Cell. Physiol. 223: 110-122, 2010. (c) 2009 Wiley-Liss, Inc. |
Affiliation:
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Cell Biophysics Group, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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4-Aminopyridine
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pharmacology Annexin A5 / metabolism Apoptosis* / drug effects Blotting, Western Cell Line Cell Size Epithelial Cells / drug effects, metabolism*, pathology Humans Hypotonic Solutions Immunohistochemistry Intermediate-Conductance Calcium-Activated Potassium Channels / drug effects, genetics, metabolism* Ion Transport Lens, Crystalline / drug effects, metabolism*, pathology Osmotic Pressure Potassium / metabolism* Potassium Channel Blockers / pharmacology Protein Kinase Inhibitors / pharmacology RNA, Messenger / metabolism Reverse Transcriptase Polymerase Chain Reaction Rubidium / metabolism Signal Transduction Staurosporine / pharmacology Stress, Physiological* Time Factors Water / metabolism |
| Chemical | |
Reg. No./Substance:
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0/Annexin A5; 0/Hypotonic Solutions; 0/Intermediate-Conductance Calcium-Activated Potassium Channels; 0/Potassium Channel Blockers; 0/Protein Kinase Inhibitors; 0/RNA, Messenger; 504-24-5/4-Aminopyridine; 62996-74-1/Staurosporine; 7440-09-7/Potassium; 7440-17-7/Rubidium; 7732-18-5/Water |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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