Stress-induced dilated cardiomyopathy in a knock-in mouse model mimicking human titin-based disease

Item Type:	Article
Title:	Stress-induced dilated cardiomyopathy in a knock-in mouse model mimicking human titin-based disease
Creators Name:	Gramlich, M. and Michely, B. and Krohne, C. and Heuser, A. and Erdmann, B. and Klaassen, S. and Hudson, B. and Magarin, M. and Kirchner, F. and Todiras, M. and Granzier, H. and Labeit, S. and Thierfelder, L. and Gerull, B.
Abstract:	Mutations in a variety of myofibrillar genes cause dilated cardiomyopathy (DCM) in humans, usually with dominant inheritance and incomplete penetrance. Here, we sought to clarify the functional effects of the previously identified DCM-causing TTN 2-bp insertion mutation (c.43628insAT) and generated a titin knock-in mouse model mimicking the c.43628insAT allele. Mutant embryos homozygous for the Ttn knock-in mutation developed defects in sarcomere formation and consequently died before E9.5. Heterozygous mice were viable and demonstrated normal cardiac morphology, function and muscle mechanics. mRNA and protein expression studies on heterozygous hearts demonstrated elevated wild-type titin mRNA under resting conditions, suggesting that up-regulation of the wild-type titin allele compensates for the unstable mutated titin under these conditions. When chronically exposed to angiotensin II or isoproterenol, heterozygous mice developed marked left ventricular dilatation (p<0.05) with impaired fractional shortening (p<0.001) and diffuse myocardial fibrosis (11.95 +/- 2.8% versus 3.7 +/-1.1%). Thus, this model mimics typical features of human dilated cardiomyopathy and may further our understanding of how titin mutations perturb cardiac function and remodel the heart.
Keywords:	Cardiomyopathy, Development, Sarcomere Formation, Genetics, Mouse Model, Heart Failure, Pathogenesis, Titin, Animals, Mice
Source:	Journal of Molecular and Cellular Cardiology
ISSN:	0022-2828
Publisher:	Elsevier
Volume:	47
Number:	3
Page Range:	352-358
Date:	September 2009
Official Publication:	https://doi.org/10.1016/j.yjmcc.2009.04.014
PubMed:	View item in PubMed

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