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Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes
11:00

Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes

Published on: September 18, 2017

Ca2+/calmodulin-dependent kinase IIdelta causes heart failure by accumulation of p53 in dilated cardiomyopathy

Haruhiro Toko1, Hidehisa Takahashi, Yosuke Kayama

  • 1Department of Cardiovascular Science and Medicine, Chiba University Graduate School of Medicine, Chiba, Japan.

Circulation
|August 18, 2010
PubMed
Abstract

Insights

A mutated cardiac alpha-actin gene caused dilated cardiomyopathy (DCM) in mice, leading to heart failure. Calcium/calmodulin-dependent kinase IIdelta (CaMKIIdelta) activation contributes to DCM by increasing p53 and cardiomyocyte apoptosis.

Area of Science:

  • Cardiovascular Biology
  • Molecular Cardiology
  • Genetics of Heart Disease

Background:

  • Dilated cardiomyopathy (DCM) is a major cause of heart failure, characterized by left ventricular dilation and dysfunction.
  • Genetic mutations, particularly in cytoskeletal and contractile protein genes, are implicated in DCM, but underlying mechanisms remain unclear.

Purpose of the Study:

  • To establish and characterize a mouse model of DCM using a mutated cardiac alpha-actin gene.
  • To investigate the molecular mechanisms linking genetic mutations to DCM pathogenesis and heart failure.

Main Methods:

  • Generation of transgenic mice (mActin-Tg) expressing a DCM-associated mutated cardiac alpha-actin gene.
  • Assessment of cardiac function, cardiomyocyte apoptosis, p53 protein levels, myofilament calcium sensitivity, and CaMKIIdelta activity in mActin-Tg mice.
  • Pharmacological inhibition of CaMKIIdelta to evaluate its role in DCM progression.

Main Results:

  • mActin-Tg mice exhibited progressive left ventricular dilatation, dysfunction, and heart failure, mimicking human DCM.
  • Increased cardiomyocyte apoptosis and elevated p53 levels were observed in mActin-Tg hearts.
  • Reduced myofilament calcium sensitivity and activated CaMKIIdelta were detected.
  • Inhibition of CaMKIIdelta attenuated cardiomyocyte apoptosis, improved cardiac function, and reduced p53 accumulation.

Conclusions:

  • CaMKIIdelta plays a crucial role in DCM pathogenesis and heart failure development.
  • CaMKIIdelta contributes to DCM by promoting p53 accumulation and cardiomyocyte apoptosis.
  • This mActin-Tg mouse model provides a valuable tool for studying DCM mechanisms and testing therapeutic strategies.

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