Upstream mechanotaxis behavior of endothelial cells

Area of Science:

• Biomedical Engineering
• Cell Biology
• Fluid Dynamics

Background:

• Vascular remodeling involves endothelial cell migration, influenced by blood flow's hemodynamic forces.
• Endothelial cells (bEnd.3) in vitro migrate upstream against applied shear stress.
• Understanding shear stress effects on endothelial cell mechanotaxis is vital for vascular biology.

Purpose of the Study:

• To investigate how varying shear stress magnitudes affect endothelial cell mechanotaxis.
• To explore the role of substrate stiffness in endothelial cell directional migration under flow.
• To elucidate the mechanisms underlying endothelial cell response to hemodynamic forces.

Main Methods:

• Exposing mouse microvessel endothelial cells (bEnd.3) to different magnitudes of unidirectional shear stress.
• Culturing cells on substrates with varying elastic moduli, mimicking physiological and pathological vessel stiffness.
• Analyzing cell migration speed, velocity components, and directional persistence using microscopy and image analysis.

Main Results:

• Increased shear stress reduced overall cell migration speed but enhanced alignment parallel to flow.
• Cells on softer, vessel-mimicking substrates exhibited greater directional persistence than on stiffer substrates.
• Enhanced directionality correlated with increased stress fiber formation and focal adhesion turnover, indicating heightened mechanotaxis.

Conclusions:

• Substrate stiffness significantly modulates endothelial cell mechanotaxis in response to shear stress.
• Vessel stiffening may impair endothelial cell mechano-sensing, hindering proper vascular remodeling and repair.
• Findings offer insights into vascular diseases, wound healing, and strategies for vascular grafts and stents.