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Title: Annexin A7 deficiency potentiates cardiac NFAT activity promoting hypertrophic signaling

Highlights: • Cardiac Anxa7 expression was up-regulated following TAC. • The hypertrophic response following TAC was augmented in Anxa7-deficient mice. • Silencing of Anxa7 increased indicators of HL-1 cardiomyocytes hypertrophy. • Silencing of Anxa7 induced Nfatc1 nuclear translocation. • Silencing of Anxa7 enhanced NFAT-dependent transcriptional activity. - Abstract: Annexin A7 (Anxa7) is a cytoskeletal protein interacting with Ca{sup 2+} signaling which in turn is a crucial factor for cardiac remodeling following cardiac injury. The present study explored whether Anxa7 participates in the regulation of cardiac stress signaling. To this end, mice lacking functional Anxa7 (anxa7{sup −/−}) and wild-type mice (anxa7{sup +/+}) were investigated following pressure overload by transverse aortic constriction (TAC). In addition, HL-1 cardiomyocytes were silenced with Anxa7 siRNA and treated with isoproterenol. Transcript levels were determined by quantitative RT-PCR, transcriptional activity by luciferase reporter assay and protein abundance by Western blotting and confocal microscopy. As a result, TAC treatment increased the mRNA and protein levels of Anxa7 in wild-type mice. Moreover, TAC increased heart weight to body weight ratio and the cardiac mRNA levels of αSka, Nppb, Col1a1, Col3a1 and Rcan1, effects more pronounced in anxa7{sup −/−} mice than in anxa7{sup +/+} mice. Silencing of Anxa7 in HL-1more » cardiomyocytes significantly increased nuclear localization of Nfatc1. Furthermore, Anxa7 silencing increased NFAT-dependent transcriptional activity as well as αSka, Nppb, and Rcan1 mRNA levels both, under control conditions and following β-adrenergic stimulation by isoproterenol. These observations point to an important role of annexin A7 in the regulation of cardiac NFAT activity and hypertrophic response following cardiac stress conditions.« less
Authors:
; ; ; ; ;  [1] ;  [2] ;  [3] ;  [2] ;  [1]
  1. Department of Physiology, University of Tübingen, Tübingen (Germany)
  2. Department of Cardiology and Cardiovascular Medicine, University of Tübingen, Tübingen (Germany)
  3. Center for Biochemistry, Institute of Biochemistry I, University of Cologne, Köln (Germany)
Publication Date:
OSTI Identifier:
22416298
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 445; Journal Issue: 1; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ACTIN; CALCIUM IONS; COLLAGEN; HEART; HYPERTROPHY; INDICATORS; INJURIES; LUCIFERASE; MESSENGER-RNA; MICE; MICROSCOPY; PEPTIDES; PHOSPHATES; POLYMERASE CHAIN REACTION; REGULATIONS; STIMULATION; STRESSES; TRANSLOCATION