Coronary arterial development is regulated by a Dll4-Jag1-EphrinB2 signaling cascade

Area of Science:

• Cardiovascular Biology
• Developmental Biology
• Molecular Biology

Background:

• Coronary arteries are vital for heart function and growth.
• The role of Notch signaling in coronary development is not fully understood.
• Notch signaling is known to be crucial for embryonic angiogenesis.

Purpose of the Study:

• To investigate the role of Notch ligands (Jag1, Dll4) and receptors in coronary development.
• To elucidate the molecular mechanisms underlying coronary plexus formation and arterial differentiation.
• To identify key signaling pathways involved in early coronary artery development.

Main Methods:

• Analysis of gene expression (Jag1, Dll4, Notch1, Efnb2) in mouse sinus venosus endocardium.
• Genetic manipulation (ligand removal, forced expression) to study gene function.
• In vitro experiments using ventricular explants and primary human endothelial cells.
• Assessment of capillary sprouting, plexus remodeling, arterial differentiation, and perivascular cell maturation.

Main Results:

• Jag1 and Dll4 are expressed in the sinus venosus endocardium.
• Jag1 removal inhibits capillary sprouting; Dll4 inactivation promotes excessive growth, indicating ligand antagonism.
• Dll4/Jag1 signaling and Mfng/Efnb2 are critical for plexus remodeling and arterial differentiation.
• Endocardial Efnb2 deletion mimics Notch mutant coronary arterial defects.

Conclusions:

• Coronary arterial precursors are specified in the sinus venosus before plexus formation.
• A Dll4-Jag1-EphrinB2 signaling cascade is essential for coronary arterial morphogenesis.
• Ligand antagonism and downstream effectors like EphrinB2 are key regulators of coronary development.