Ah Receptor Signaling Controls the Expression of Cardiac Development and Homeostasis Genes

Area of Science:

• Developmental Biology
• Cardiovascular Science
• Toxicology

Background:

• Congenital heart disease (CHD) is a major cause of infant mortality, with its exact causes often unclear.
• The aryl hydrocarbon receptor (AHR) is a known regulator of gene expression, but its role in heart development is not fully understood.

Purpose of the Study:

• To investigate the role of the aryl hydrocarbon receptor (AHR) in regulating cardiogenesis and its potential link to congenital heart disease (CHD).

Main Methods:

• Investigated AHR function by genetically ablating the AHR gene (Ahr(-/-)) and by exposing wild-type embryos to an AHR agonist during early development.
• Analyzed structural and functional cardiac abnormalities, fetal heart physiology (heart rate, ventricle dilation, stroke volume, ejection fraction), and molecular mechanisms including gene expression, transcription factors (NKX2.5), energy metabolism (oxidative phosphorylation, TCA cycle), and mitochondrial function.

Main Results:

• Both AHR gene ablation and agonist exposure during development resulted in similar cardiac abnormalities, including altered fetal heart physiology.
• Disruption of endogenous AHR function led to dysregulation of cardiogenesis, affecting NKX2.5 signaling, energy balance, and mitochondrial homeostasis.
• AHR signaling is critical for maintaining cardiac differentiation and function.

Conclusions:

• Aryl hydrocarbon receptor (AHR) signaling is essential for normal mammalian heart development, regulating pathways vital for cellular metabolism, cardiogenesis, and cardiac function.
• AHR signaling pathways are potential targets for environmental factors implicated in the etiology of congenital heart disease (CHD).