Document Detail


Hypercholesterolemia induces up-regulation of KACh cardiac currents via a mechanism independent of phosphatidylinositol 4,5-bisphosphate and Gβγ.
MedLine Citation:
PMID:  22174416     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hypercholesterolemia is a well-known risk factor for cardiovascular disease. In the heart, activation of K(ACh) mediates the vagal (parasympathetic) negative chronotropic effect on heart rate. Yet, the effect of cholesterol on K(ACh) is unknown. Here we show that cholesterol plays a critical role in modulating K(ACh) currents (I(K,ACh)) in atrial cardiomyocytes. Specifically, cholesterol enrichment of rabbit atrial cardiomyocytes led to enhanced channel activity while cholesterol depletion suppressed I(K,ACh). Moreover, a high-cholesterol diet resulted in up to 3-fold increase in I(K,ACh) in rodents. In accordance, elevated currents were observed in Xenopus oocytes expressing the Kir3.1/Kir3.4 heteromer that underlies I(K,ACh). Furthermore, our data suggest that cholesterol affects I(K,ACh) via a mechanism which is independent of both PI(4,5)P(2) and Gβγ. Interestingly, the effect of cholesterol on I(K,ACh) is opposite to its effect on I(K1) in atrial myocytes. The latter are suppressed by cholesterol enrichment and by high-cholesterol diet, and facilitated following cholesterol depletion. These findings establish that cholesterol plays a critical role in modulating I(K,ACh) in atrial cardiomyocytes via a mechanism independent of the channel's major modulators.
Authors:
Wu Deng; Anna N Bukiya; Aldo A Rodríguez-Menchaca; Zhe Zhang; Clive M Baumgarten; Diomedes E Logothetis; Irena Levitan; Avia Rosenhouse-Dantsker
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-12-15
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  287     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-15     Completed Date:  2012-04-16     Revised Date:  2013-04-12    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4925-35     Citation Subset:  IM    
Affiliation:
Department of Medicine, Pulmonary Section, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cholesterol / metabolism
Dietary Fats / adverse effects,  pharmacology
G Protein-Coupled Inwardly-Rectifying Potassium Channels / biosynthesis*,  genetics
Heart Atria / metabolism,  pathology
Hyperhomocysteinemia / chemically induced,  genetics,  metabolism*
Myocytes, Cardiac / metabolism*,  pathology
Phosphatidylinositol 4,5-Diphosphate / genetics,  metabolism*
Rabbits
Up-Regulation*
Xenopus laevis
Grant Support
ID/Acronym/Agency:
HL-059949/HL/NHLBI NIH HHS; HL-073965/HL/NHLBI NIH HHS; HL-083298/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Dietary Fats; 0/G Protein-Coupled Inwardly-Rectifying Potassium Channels; 0/Phosphatidylinositol 4,5-Diphosphate; 57-88-5/Cholesterol
Comments/Corrections

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


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