Parvins Are Required for Endothelial Cell-Cell Junctions and Cell Polarity During Embryonic Blood Vessel Formation

Area of Science:

• Vascular biology
• Cell biology
• Developmental biology

Background:

• Integrin signaling is crucial for endothelial cell (EC) junction formation, polarity, and basement membrane deposition during vascular development.
• Parvins (α-parvin and β-parvin) link integrins to the actin cytoskeleton.
• α-parvin is known to be important for later embryonic vascular development, but the role of parvins in early development is unclear.

Purpose of the Study:

• To investigate the function of endothelial parvins during early embryonic vascular development.
• To determine the specific roles of α-parvin and β-parvin isoforms in the developing vasculature.

Main Methods:

• Generation of mice lacking both α-parvin and β-parvin in endothelial cells (α-pvΔEC;β-pv-/- mice).
• Analysis of embryonic vascular development, including morphology, cell junctions, polarity, and basement membrane integrity.
• Assessment of pericyte-vessel interactions.

Main Results:

• Mice lacking both parvin isoforms in ECs exhibit embryonic lethality around E11.5.
• These embryos display severe vascular defects, including hemorrhages, immature capillary networks, and CNS vascular abnormalities.
• Defects include disorganized EC-cell junctions, impaired apical-basal polarity, discontinuous basement membranes, and poor pericyte association.

Conclusions:

• Endothelial parvins are critical for the proper organization of endothelial cell-cell junctions.
• Parvins are essential for establishing endothelial apical-basal polarity and maintaining basement membrane integrity.
• These functions are vital for embryonic vascular development and survival.