Cxcl1 monomer-dimer equilibrium controls neutrophil extravasation.

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Neutrophil recruitment is vital for host defense against infection.
• Chemokines, like Cxcl1, orchestrate neutrophil migration through a series of steps.
• Cxcl1's function is modulated by its monomer-dimer equilibrium and receptor binding.

Purpose of the Study:

• To investigate how Cxcl1's monomer-dimer equilibrium influences neutrophil extravasation.
• To elucidate the role of Cxcl1 properties in neutrophil recruitment dynamics.

Main Methods:

• Intravital microscopy of the cremaster muscle.
• Whole-mount immunofluorescence.
• Neutrophil arrest assays.

Main Results:

• Trapped Cxcl1 dimers exhibited faster rolling but reduced adhesion and extravasation compared to wild-type Cxcl1.
• Cxcl1 dimers showed impaired LFA-1-mediated neutrophil arrest.
• Impaired arrest was linked to reduced Cxcr2-mediated ERK signaling.

Conclusions:

• Cxcl1 monomer-dimer equilibrium is a critical regulator of early neutrophil recruitment.
• The monomer form of Cxcl1, with potent Cxcr2 activity, is essential for effective neutrophil extravasation.