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Calpain3 expression during human cardiogenesis
F Fougerousse1, L V Anderson, A L Delezoide
1URA 1922-G¿en¿ethon, 1 rue de l'Internationale, BP 60, 91002, Evry, France.
Insights
Calpain3 transcripts are found in the developing human heart, but the protein is only detected in skeletal muscle. Titin RNA and protein are early cardiac development markers.
Area of Science:
- Developmental biology
- Molecular biology
- Cardiology
Background:
- Calpain3 (gene) is implicated in limb girdle muscular dystrophy type 2A.
- Calpain3 transcripts are detected in non-skeletal muscle organs during human development, notably the embryonic heart.
Purpose of the Study:
- To precisely examine the spatio-temporal transcription pattern of calpain3 during human cardiogenesis.
- To investigate the appearance of calpain3 protein in fetal tissues.
- To correlate calpain3 expression with titin expression during heart development.
Main Methods:
- Analysis of calpain3 and titin RNA and protein expression.
- Study of human embryonic and fetal tissues.
- Spatio-temporal expression pattern analysis.
Main Results:
- Titin RNA and protein serve as precocious developmental cardiac markers, appearing before endocardial tube fusion.
- Calpain3 RNA disappears from the ventricular compartment later in embryonic heart development.
- Despite transcript presence in the heart, calpain3 protein is exclusively detected in skeletal muscle.
Conclusions:
- Titin is a reliable early marker for cardiac development.
- Calpain3 expression in the heart is complex, with transcripts present but protein absent in cardiac tissue.
- The tissue-specific expression of calpain3 protein highlights distinct roles beyond skeletal muscle, warranting further investigation.
Abstract:
Transcripts of calpain3, the gene involved in limb girdle muscular dystrophy type 2A, appear in organs other than the skeletal muscle during human development, the first of which being the early embryonic heart. We examined more precisely the spatio-temporal transcription pattern of calpain3 during human cardiogenesis and the appearance of its protein in fetal tissues, and correlated it to titin expression. Different events of the heart's maturation can be recognized: (i) the presence of titin RNA or protein constitute very precocious developmental cardiac markers appearing before the fusion of the two lateral endocardial tubes; (ii) the disappearance of calpain3 RNA from the ventricular compartment later in the embryonic heart. Finally, although calpain3 transcripts are present in the heart, the corresponding protein is not detected elsewhere than in skeletal muscle.