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Cardiovascular lesions and skeletal myopathy in mice lacking desmin
Z Li1, E Colucci-Guyon, M Pinçon-Raymond
1Biologie moléculaire de la différenciation, SCME, Paris, France.
Abstract:
In order to further our understanding of the biological role of desmin, the muscle-specific intermediate filament protein, a null mutation in the desmin gene was introduced into the germ line of mice. Despite the complete lack of desmin, these mice developed and reproduced. Since we show that skeletal, cardiac, and smooth muscles form in the Des-/- mice, it is reasonable to propose that desmin is not essential for myogenic commitment or for myoblast fusion or differentiation in vivo. However, morphological abnormalities were observed in the diaphragm of adult mice; these were demonstrated by disorganized, distended, and nonaligned fibers. The heart presented areas of hemorrhaging in which fibrosis and ischemia were observed. We have also shown that the absence of desmin produces specific defects in smooth muscles. In conclusion, our results have demonstrated that desmin is not required for the differentiation of skeletal, cardiac, and smooth muscles but is essential to strengthen and maintain the integrity of these tissues.
Insights
Desmin is not essential for muscle formation but is crucial for maintaining tissue integrity. Absence of desmin in mice leads to muscle abnormalities, highlighting its role in tissue strength.
Area of Science:
- Muscle biology
- Cellular and molecular biology
- Biochemistry
Background:
- Desmin is a muscle-specific intermediate filament protein.
- Its precise biological role in muscle tissue is not fully understood.
Purpose of the Study:
- To investigate the biological role of desmin.
- To determine if desmin is essential for muscle development and integrity.
Main Methods:
- Generation of desmin-null (Des-/-) mice.
- Analysis of skeletal, cardiac, and smooth muscle formation and morphology in Des-/- mice.
Main Results:
- Desmin-null mice developed and reproduced normally.
- Skeletal, cardiac, and smooth muscles formed in the absence of desmin.
- Morphological abnormalities, including disorganized fibers, fibrosis, and ischemia, were observed in diaphragm and heart tissues.
- Specific defects were noted in smooth muscles.
Conclusions:
- Desmin is not essential for myogenic commitment, fusion, or differentiation.
- Desmin is crucial for strengthening and maintaining the integrity of skeletal, cardiac, and smooth muscle tissues.