Tbx1 regulates brain vascularization

Area of Science:

• Developmental Biology
• Vascular Biology
• Genetics

Background:

• TBX1 is a key gene in 22q11.2 deletion syndrome (22q11.2DS).
• Previous work established TBX1's role in lymphatic vasculature development via VEGFR3 activation in endothelial cells (EC).
• The function of TBX1 in brain angiogenesis remained largely unexplored.

Purpose of the Study:

• To investigate the role of TBX1 in regulating brain angiogenesis.
• To elucidate the molecular mechanisms by which TBX1 controls brain vascular development.
• To explore the potential link between TBX1 function and brain anomalies in 22q11.2DS.

Main Methods:

• Loss-of-function genetics in mouse models.
• Molecular approaches to study gene regulation in brain ECs.
• In vitro 3D endothelial cell culture (matrigel) systems.

Main Results:

• TBX1 regulates VEGFR3 and DLL4 gene expression in brain ECs.
• Loss of TBX1 leads to brain vascular defects, including hyperplasia, increased sprouting, and disorganization.
• The observed vascular phenotype is cell-autonomous to ECs and results in impaired brain perfusion and hypoxia.
• DLL4/Notch1-VEGFR3 axis is identified as a key regulatory pathway for TBX1's function in negatively regulating angiogenesis.

Conclusions:

• TBX1 acts as a novel negative regulator of brain angiogenesis.
• The DLL4/Notch1-VEGFR3 pathway is critical for TBX1's function in brain vascularization.
• Clinicians should investigate potential brain microvascular anomalies in 22q11.2DS patients.