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Defective Vagal Innervation in Murine Tbx1 Mutant Hearts
Amélie Calmont1,2, Naomi Anderson3,4, Jenifer P Suntharalingham5
1INSERM UMRS 1155, Centre for Kidney Research, 4 Rue de la Chine, 75020 Paris, France. amelie.calmont@inserm.fr.
Journal of Cardiovascular Development and Disease
|September 26, 2018
Summary
Reduced T-box transcription factor 1 (TBX1) impacts vagal innervation of the heart in 22q11.2 deletion syndrome mouse models. This may lead to a pro-arrhythmic substrate in patients.
Area of Science:
- Developmental Biology
- Genetics
- Cardiology
Background:
- Haploinsufficiency of the T-box transcription factor TBX1 causes 22q11.2 deletion syndrome features.
- TBX1 is crucial for pharyngeal development, with mutants showing cranial ganglion and neural crest defects.
Purpose of the Study:
- To investigate the role of TBX1 in the parasympathetic (vagal) innervation of the heart.
- To characterize TBX1 function in vagal innervation using a mouse model.
Main Methods:
- Utilized an allelic series of Tbx1 mouse mutants.
- Employed embryo tissue explants and cardiac electrophysiology.
- Assessed neural crest cell migration and cranial ganglia development.
- Monitored heart rate response to carbachol using telemetry.
Main Results:
- Reduced nerve branch length in Tbx1 mutant hearts (Tbx1+/- and Tbx1neo2/-).
- Normal neural crest migration to the heart in Tbx1+/- but not Tbx1neo2 mutants.
- Cranial ganglia IX and X fused in Tbx1neo2/- mutants, with intact neuronal differentiation.
- Tbx1+/- hearts recovered heart rate faster post-carbachol challenge compared to controls.
Conclusions:
- TBX1 deficiency impairs vagal innervation of the heart.
- Altered vagal tone in Tbx1+/- mutants suggests a potential pro-arrhythmic substrate in 22q11.2 deletion syndrome patients.
- TBX1 is essential for normal cardiac autonomic innervation development.
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