Document Detail


Beta1 integrins modulate beta-adrenergic receptor-stimulated cardiac myocyte apoptosis and myocardial remodeling.
MedLine Citation:
PMID:  17283249     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Sympathetic nerve activity increases in the heart during cardiac failure. Here, we hypothesized that beta1 integrins play a protective role in chronic beta-adrenergic receptor-stimulated cardiac myocyte apoptosis and heart failure. L-isoproterenol (iso; 400 microg/kg per hour) was infused in a group of wild-type (WT) and beta1 integrin heterozygous knockout (hKO) mice. Left ventricular structural and functional remodeling was studied at 7 and 28 days of iso-infusion. Western blot analysis demonstrated reduced beta1 integrin levels in the myocardium of hKO-sham. Iso-infusion increased heart weight:body weight ratios in both groups. However, the increase was significantly higher in WT-iso. M-mode echocardiography indicated increased left ventricular end-diastolic diameter, percentage of fractional shortening, and ejection fraction in the WT-iso group. The percentage of fractional shortening and ejection fraction were significantly lower in hKO-iso versus hKO-sham and WT-iso. Peak left ventricular developed pressure and left ventricular end-diastolic pressure measured using Langendorff-perfusion analyses were significantly higher in the WT-iso group (P<0.05 versus WT-sham and hKO-Iso). The number of TUNEL-positive myocytes was significantly higher in hKO-iso hearts 7 and 28 days after iso-infusion. The increase in myocyte cross-sectional area and fibrosis was higher in the WT-iso group. Matrix metalloproteinase-9 protein levels were significantly higher in WT-iso, whereas matrix metalloproteinase-2 levels were increased in hKO-iso hearts. Iso-infusion increased phosphorylation of c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2 in both groups. The increase in c-Jun N-terminal kinase phosphorylation was significantly higher in hKO-iso (P<0.001 versus WT-iso). Thus, beta1 integrins play a crucial role in beta-adrenergic receptor-stimulated myocardial remodeling with effects on cardiac myocyte hypertrophy, apoptosis, and left ventricular function.
Authors:
Prasanna Krishnamurthy; Venkateswaran Subramanian; Mahipal Singh; Krishna Singh
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2007-02-05
Journal Detail:
Title:  Hypertension     Volume:  49     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2007 Apr 
Date Detail:
Created Date:  2007-03-22     Completed Date:  2007-04-05     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  United States    
Other Details:
Languages:  eng     Pagination:  865-72     Citation Subset:  IM    
Affiliation:
Department of Physiology, James H. Quillen College of Medicine, James H. Quillen Veterans Affairs Medical Center, East Tennessee State University, Johnson City, 37614, USA.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Agonists / pharmacology*
Animals
Antigens, CD29 / genetics,  metabolism*
Apoptosis*
Cardiac Output, Low / enzymology,  physiopathology*,  ultrasonography
Echocardiography
Extracellular Signal-Regulated MAP Kinases / metabolism
Fibrosis
Isoproterenol / pharmacology*
JNK Mitogen-Activated Protein Kinases / metabolism
Matrix Metalloproteinase 2 / metabolism
Matrix Metalloproteinase 9 / metabolism
Mice
Mice, Knockout
Myocardial Contraction / drug effects
Myocytes, Cardiac* / drug effects,  enzymology
Phosphorylation / drug effects
Pressure
Stroke Volume / drug effects
Ventricular Function, Left
Ventricular Remodeling*
Grant Support
ID/Acronym/Agency:
HL-071519/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Antigens, CD29; 7683-59-2/Isoproterenol; EC 2.7.11.24/Extracellular Signal-Regulated MAP Kinases; EC 2.7.11.24/JNK Mitogen-Activated Protein Kinases; EC 3.4.24.24/Matrix Metalloproteinase 2; EC 3.4.24.35/Matrix Metalloproteinase 9
Comments/Corrections
Comment In:
Hypertension. 2007 Apr;49(4):767-8   [PMID:  17296873 ]

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


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