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Defective chemoattractant-induced calcium signalling in S100A9 null neutrophils
E McNeill1, S J Conway, H L Roderick
1Leukocyte Adhesion Laboratory, Cancer Research UK London Research Institute (CRUK LRI), 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
Cell Calcium
|July 4, 2006
Summary
The S100A9 protein complex is crucial for regulating calcium (Ca2+) signaling in neutrophils during inflammatory responses. Its absence alters calcium release pathways, impacting neutrophil function.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- S100A9 and S100A8 form a cytosolic Ca2+ binding complex abundant in neutrophils.
- This complex contains EF-hand motifs, suggesting a role in Ca2+ signaling.
Purpose of the Study:
- To investigate the role of the S100A9/S100A8 complex in neutrophil Ca2+ signaling.
- To determine how the absence of S100A9 affects Ca2+ responses to inflammatory stimuli.
Main Methods:
- Utilized neutrophils from S100A9 null mice.
- Assessed Ca2+ signaling responses to chemokines (MIP-2, KC) and formylated peptides (FMLP).
- Investigated signaling pathways involving G proteins, phospholipase C beta (PLCbeta), and diacylglycerol (DAG).
Main Results:
- The S100A9 complex does not buffer acute cytosolic Ca2+ elevations.
- Ca2+ responses to inflammatory agents are altered in S100A9 null neutrophils.
- Signaling is dysregulated at the PLCbeta level, with altered sensitivity to inhibition and DAG.
Conclusions:
- The S100A9/S100A8 complex plays a critical role in regulating inflammatory agonist-induced Ca2+ release in neutrophils.
- A specific defect in PLCbeta-mediated signaling is identified in neutrophils lacking S100A9.
- This study highlights a novel function of S100A9 in modulating neutrophil inflammatory responses.
