VEGFR2 is required for VEGF-C-VEGFR3-PI3Kα-mediated sprouting lymphangiogenesis

Area of Science:

• Molecular Biology
• Developmental Biology
• Cell Biology

Background:

• Lymphatic vessels are crucial for maintaining tissue fluid balance and immune function.
• Vascular endothelial growth factor C (VEGF-C) signaling through VEGFR3 is known to regulate lymphatic vessel growth.
• The precise mechanisms balancing lymphatic endothelial cell (LEC) proliferation and sprouting remain incompletely understood.

Purpose of the Study:

• To elucidate the role of alternative receptors in VEGF-C-mediated lymphatic vessel sprouting.
• To understand how VEGF-C signaling coordinates LEC proliferation and sprouting for functional lymphangiogenesis.
• To investigate the interplay between VEGFR2, VEGFR3, and downstream effectors in lymphatic development.

Main Methods:

• Utilized high-fidelity conditional genetics in mouse models.
• Employed receptor-specific ligands to probe signaling pathways.
• Investigated protein proximity and cell-surface localization using in vivo and in vitro techniques.

Main Results:

• VEGFR2 is essential for VEGF-C-driven lymphatic endothelial cell sprouting, but not proliferation.
• Loss of VEGFR2 specifically impairs LEC sprouting in response to VEGF-C.
• Deletion of PI3Kα, a VEGFR3 effector, completely blocks lymphangiogenesis.
• VEGF-C signaling modulates the relative cell-surface availability of VEGFR2 and VEGFR3, priming LECs for sprouting.

Conclusions:

• VEGFR2 acts as an alternative receptor that cooperates with VEGFR3 in VEGF-C-mediated lymphatic sprouting.
• PI3Kα is a critical downstream mediator of VEGFR3 in lymphangiogenesis.
• Receptor coordination between VEGFR2 and VEGFR3 balances LEC proliferation and sprouting, ensuring functional lymphatic network formation.