Platelets modulate endothelial cell response to dynamic shear stress through PECAM-1

Area of Science:

• Cardiovascular Biology
• Endothelial Cell Biology
• Platelet Biology

Background:

• Vascular endothelial cells and platelets are sensitive to shear stress.
• Platelet-endothelial cell interactions influence platelet activation under flow.
• Endothelial cell inflammatory responses are affected by shear stress.

Purpose of the Study:

• Investigate how platelet-endothelial cell interaction affects endothelial cell inflammatory responses under flow.
• Determine the role of PECAM-1 in mediating platelet-endothelial cell interactions under shear stress.

Main Methods:

• Exposed human coronary artery endothelial cells to normal or low pulsatile shear stress with/without platelets.
• Measured endothelial cell ICAM-1 and PECAM-1 expression/phosphorylation.
• Quantified platelet adhesion and suppressed PECAM-1 using siRNA.

Main Results:

• Low shear stress increased endothelial cell ICAM-1 expression.
• Platelet adhesion increased under low shear stress, co-localizing with PECAM-1.
• Platelets inhibited low shear stress-induced ICAM-1 upregulation; PECAM-1 suppression reduced platelet adhesion and ICAM-1 expression.

Conclusions:

• PECAM-1 mediates platelet adhesion to endothelial cells under shear stress.
• Platelet binding to endothelial cells interferes with mechanotransduction via PECAM-1.
• This interaction modulates endothelial cell inflammatory responses to pathological shear flow.