Protrudin regulates FAK activation, endothelial cell migration and angiogenesis

Area of Science:

• Cell Biology
• Molecular Biology
• Vascular Biology

Background:

• Endothelial cells form sprouts and migrate during angiogenesis.
• The role of endoplasmic reticulum (ER)-anchored proteins in this process is not fully understood.

Purpose of the Study:

• To investigate the function of Protrudin in endothelial cell protrusion, migration, and angiogenesis.
• To elucidate the molecular mechanisms underlying Protrudin's role in these processes.

Main Methods:

• Protrudin knockdown in primary endothelial cells (HUVECs) and human aortic endothelial cells (HAECs).
• RNA sequencing analysis to identify affected cellular functions.
• Western blotting to assess focal adhesion kinase (FAK) activation and phospho-FAK distribution.
• Analysis of mTOR and S6K activation.
• In vivo studies using mice with global Protrudin deletion.

Main Results:

• Protrudin knockdown impairs angiogenic tube formation in HUVECs.
• Cell migration is significantly affected in Protrudin-knockdown HUVECs.
• Protrudin knockdown inhibits FAK activation and disrupts phospho-FAK polarization in endothelial cells.
• Protrudin reduction leads to mTOR accumulation and decreased VEGF-mediated S6K activation, though mTOR is not implicated in the observed angiogenesis inhibition.
• Global Protrudin deletion in mice reduces retinal vascular progression.

Conclusions:

• Protrudin plays a critical role in endothelial cell migration and angiogenesis.
• Defects in FAK activation and its subcellular distribution due to Protrudin knockdown negatively impact endothelial cell migration and angiogenesis.
• Protrudin is a novel key regulator of endothelial cell migration and angiogenesis.