Related Experiment Videos
Calpain regulates neutrophil chemotaxis
M A Lokuta1, P A Nuzzi, A Huttenlocher
1Department of Pediatrics, University of Wisconsin, 1300 University Avenue, Madison, WI 53706, USA. malokuta@facstaff.wisc.edu
Summary
Calpain activity in resting neutrophils negatively regulates cell movement. Inhibiting calpain promotes neutrophil polarization and migration, suggesting a role in chemotaxis signaling pathways.
Area of Science:
- Cell Biology
- Immunology
- Biochemistry
Background:
- Cell polarization is crucial for directed cell migration.
- Neutrophil chemotaxis involves complex signaling pathways.
Purpose of the Study:
- To investigate the role of calcium-dependent protease calpain in neutrophil chemotaxis.
- To elucidate calpain's function in neutrophil polarization and migration.
Main Methods:
- Calpain inhibition assays in neutrophils.
- Analysis of neutrophil adhesion, polarization, and chemokinesis.
- Investigation of downstream signaling molecules like Cdc42 and Rac.
- Assessment of chemotaxis in response to chemoattractants like IL-8 and fMLP.
Main Results:
- Calpain inhibition induced neutrophil adhesion, polarization, and chemokinesis without external activators.
- Constitutive calpain activity in resting neutrophils acts as a negative regulator of protrusion and migration.
- Specific inhibition of mu-calpain, not m-calpain, triggered polarization and chemokinesis.
- Calpain inhibition's effects on chemokinesis were independent of G protein-coupled receptors, suggesting downstream function.
- Both calpain inhibition and chemoattractant stimulation increased Cdc42 and Rac activation.
- Calpain inhibition reduced neutrophil chemotaxis and directional persistence.
Conclusions:
- Constitutive calpain activity negatively regulates neutrophil protrusion and migration.
- Calpain functions downstream of G protein-coupled receptors in neutrophil chemotaxis.
- Localized calpain activity modulation is a potential regulator of neutrophil chemotaxis.