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A murine model for hypertrophic cardiomyopathy
K L Vikstrom1, S M Factor, L A Leinwand
1Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Insights
Familial hypertrophic cardiomyopathy (FHC) is a genetic heart disease. Transgenic mice expressing mutant myosin heavy chains develop FHC, providing a model for studying this condition.
Area of Science:
- Cardiovascular Genetics
- Molecular Cardiology
- Animal Models
Background:
- Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant genetic heart disease and a leading cause of sudden death in young athletes.
- Mutations in contractile proteins, such as cardiac myosin heavy chains, are implicated in FHC, suggesting it is a sarcomere disease.
Purpose of the Study:
- To develop an animal model for familial hypertrophic cardiomyopathy (FHC).
- To investigate the role of mutant cardiac myosin heavy chains in the pathogenesis of FHC.
Main Methods:
- Generation of five lines of transgenic mice expressing a mutant cardiac myosin heavy chain in their hearts.
- Histopathological analysis of mouse hearts to identify disease features.
- Assessment of transgene expression and its correlation with cardiac pathology.
Main Results:
- Transgenic mouse hearts exhibited histopathological features consistent with human FHC.
- Enlarged left ventricles were observed in the hearts of mice expressing the mutant myosin.
- The mutant protein acted in a dominant-negative manner, constituting 5-10% of total cardiac myosin.
- Pathology was confined to the left ventricle despite transgene expression in all heart chambers.
Conclusions:
- The developed transgenic mouse model effectively recapitulates key features of familial hypertrophic cardiomyopathy (FHC).
- The findings suggest that left ventricular pathology in FHC may involve secondary responses to factors like hemodynamics.
- This model provides a valuable tool for further research into FHC mechanisms and potential therapies.
Abstract:
A leading cause of sudden death among young athletes is the autosomal dominant genetic heart disease, familial hypertrophic cardiomyopathy (FHC). Mutations in several contractile proteins, including cardiac myosin heavy chains, have been described in families with FHC, leading to the hypothesis that FHC is a disease of the sarcomere (17). To create an animal model for this disease, five lines of transgenic mice have been produced that express a mutant myosin heavy chain in their hearts. The hearts of these mice exhibit the histopathological features seen in patients and demonstrate enlarged left ventricles. Our analysis suggests that the mutant protein acts as a dominant negative, since it constitutes only 5-10% of the total myosin in the heart. In addition, while the transgene is expressed in all chambers of the heart, only the left ventricle demonstrates pathology and enlargement, suggesting that several prominent features of the disease represent secondary responses influenced by other factors, such as hemodynamics.