Adhesive dynamics simulation of neutrophil arrest with deterministic activation

Area of Science:

• Immunology
• Computational Biology
• Biophysics

Background:

• Neutrophil activation, crucial for inflammation, involves a transition from rolling to firm adhesion.
• Selectins mediate rolling, while beta2-integrins mediate firm adhesion, but the dynamic mechanism linking them is unclear.
• E-selectin ligation can trigger neutrophil firm adhesion via a MAP-kinase cascade.

Purpose of the Study:

• To investigate the dynamic mechanism of neutrophil arrest.
• To develop an integrated computational model linking selectin engagement to integrin activation and firm adhesion.
• To understand how intracellular signaling influences neutrophil activation and adhesion timescales.

Main Methods:

• Combined mechanics-based leukocyte adhesion modeling (adhesive dynamics) with signal transduction pathway modeling.
• Developed a tunable integrin activation module within the adhesive dynamics framework.
• Related activation function properties to rolling dynamics and arrest time/distance.

Main Results:

• The integrated model successfully links selectin engagement to integrin activation and subsequent neutrophil arrest.
• The model demonstrates how intracellular signaling dynamics can dictate the timescale of neutrophil adhesion.
• Properties of the integrin activation function correlate with rolling behavior and arrest parameters.

Conclusions:

• Intracellular signaling plays a critical role in regulating the kinetics of neutrophil activation and firm adhesion.
• The developed computational model provides a framework for understanding the dynamic interplay between mechanical forces and signaling pathways in leukocyte adhesion.
• This approach offers insights into the mechanisms governing neutrophil arrest and subsequent diapedesis during inflammation.