Technical Advance: Changes in neutrophil migration patterns upon contact with platelets in a microfluidic assay

Area of Science:

• Immunology
• Hematology
• Biomedical Engineering

Background:

• Neutrophils are primary immune responders, but platelets also play a crucial role in early inflammation.
• Platelet-neutrophil interactions are vital for immune responses but challenging to study with traditional methods like intravital microscopy.
• Existing methods for studying platelet-neutrophil interactions are laborious and have low throughput.

Purpose of the Study:

• To develop and optimize a high-throughput ex vivo microfluidic platform for studying platelet-neutrophil interactions.
• To analyze changes in neutrophil motility upon direct contact with platelets.
• To identify the molecular mechanisms mediating neutrophil-platelet interactions.

Main Methods:

• Development and optimization of an ex vivo microfluidic platform for single-cell analysis of platelet-neutrophil interactions.
• Measurement of neutrophil motility (distance, direction changes, velocity) in response to platelet contact.
• Investigation of molecular interactions, specifically CD62P-CD162, using the microfluidic platform.

Main Results:

• The developed microfluidic platform enables high-throughput, single-cell level measurement of platelet-neutrophil interactions.
• Direct contact with platelets significantly enhances neutrophil motility, including increased travel distance and velocity.
• Neutrophil-platelet interactions are transient, mediated by CD62P-CD162, and occur at the neutrophil uropod, consistent with in vivo observations.

Conclusions:

• The novel microfluidic platform accelerates the study of platelet-neutrophil interactions.
• Platelet contact induces a distinct 'crawling' and oscillatory neutrophil behavior, validating the platform's utility.
• This research provides a new tool for exploring the complex relationship between platelets and neutrophils in immunity and inflammation.