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A Pipeline to Characterize Structural Heart Defects in the Fetal Mouse
Published on: December 16, 2022
Left cardiac isomerism in the Sonic hedgehog null mouse
Victoria Hildreth1, Sandra Webb, Bill Chaudhry
1Institute of Human Genetics, Newcastle University, UK.
Journal of Anatomy
|June 23, 2009
Summary
Sonic hedgehog (Shh) null mouse hearts exhibit left atrial appendage isomerism and heart defects, modeling human conditions. Shh loss impacts laterality and second heart field cell contribution, causing these malformations.
Area of Science:
- Developmental biology
- Cardiovascular research
- Genetics
Background:
- Sonic hedgehog (Shh) is crucial for embryonic sidedness.
- Congenital heart defects, including left isomerism, affect human development.
Purpose of the Study:
- To investigate the cardiac morphology in Shh null mouse embryos.
- To elucidate the role of Shh in heart development and laterality.
- To understand the contribution of the second heart field (Shh-dependent) to these defects.
Main Methods:
- Morphological analysis of Shh null mouse hearts.
- Gene expression analysis (Pitx2c, Isl1).
- Experimental manipulation of second heart field cell migration using dominant-negative Rho kinase.
Main Results:
- Shh null hearts display left atrial appendage isomerism, atrioventricular septal defects, and a common atrioventricular junction.
- Pitx2c expression confirms left isomerism in Shh mutants.
- Reduced Isl1-expressing second heart field derivatives observed in Shh null hearts.
- Experimental disruption of second heart field migration mimicked some Shh null defects but not atrial isomerism.
Conclusions:
- The Shh null mouse is a relevant model for left atrial appendage isomerism and associated heart defects.
- Shh signaling is critical for establishing cardiac laterality.
- Reduced second heart field contribution exacerbates Shh-loss-related cardiac malformations.
