Endothelial Surface Protrusion by a Point Force

Area of Science:

• Cellular mechanics
• Immunology
• Biophysics

Background:

• Leukocyte rolling on endothelium involves cell surface protrusion and membrane tether extraction.
• While leukocyte protrusion is known, endothelial cell (EC) protrusion has not been confirmed.
• Understanding EC mechanics is vital for leukocyte-endothelial cell interactions.

Purpose of the Study:

• To investigate the existence and properties of endothelial cell surface protrusion.
• To determine factors influencing EC surface protrusion during simulated leukocyte adhesion.
• To integrate EC protrusion into models of leukocyte rolling stability.

Main Methods:

• Micropipette aspiration technique to apply controlled forces to ECs.
• Analysis of EC deformation under varying force loading rates and cytoskeletal integrity.
• Experimental setup involving neutrophils directly interacting with ECs.

Main Results:

• Endothelial cells exhibit surface protrusion when subjected to a point force, similar to leukocytes.
• EC protrusional stiffness and crossover force depend on force loading rate and cytoskeletal integrity.
• Simultaneous protrusion from both ECs and neutrophils occurs, modeled as series springs.

Conclusions:

• Endothelial cell surface protrusion is a confirmed phenomenon.
• EC protrusion plays a significant role in stabilizing leukocyte rolling.
• Existing models of leukocyte rolling require incorporation of EC surface protrusion for comprehensive understanding.