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C-terminal SRC kinase controls acute inflammation and granulocyte adhesion
Richard M Thomas1, Christian Schmedt, Marco Novelli
1University College London, Department of Immunology and Molecular Pathology, The Windeyer Institute of Medical Sciences, 46 Cleveland Street, London W1T 4JF, United Kingdom.
Immunity
|February 21, 2004
Summary
The regulator of Src family kinases, Csk, controls acute inflammation by preventing premature granulocyte activation and promoting their migration. Inactivating Csk in granulocytes leads to heightened inflammatory responses and hypersensitivity to endotoxin shock.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- The regulator of Src family kinases, Csk, is widely expressed and plays a role in cellular signaling.
- Understanding Csk's role in granulocytes is crucial for comprehending inflammatory processes.
Purpose of the Study:
- To investigate the role of Csk in granulocytes in the context of acute inflammation in vivo.
- To determine if Csk regulates granulocyte activation, adhesion, and migration.
Main Methods:
- Conditional mutagenesis (Cre/loxP) was used to inactivate Csk specifically in granulocytes, creating Csk-GEcre mice.
- Analysis of inflammatory responses, hypersensitivity to LPS-induced shock, and in vitro granulocyte function (degranulation, integrin induction, adhesion, migration).
- Assessment of signaling protein phosphorylation (Syk, Paxillin) in mutant granulocytes.
Main Results:
- Csk-GEcre mice exhibited acute multifocal inflammation in skin and lung, which was dependent on microbial presence.
- Mutant mice showed hypersensitivity to LPS-induced shock.
- Csk-deficient granulocytes displayed enhanced spontaneous and ligand-induced degranulation, hyperadhesion, impaired migration, and hyperphosphorylation of Syk and Paxillin.
Conclusions:
- Csk acts as a critical negative regulator of granulocyte activation, preventing premature responses.
- Csk is essential for setting the activation threshold, ensuring proper ligand engagement for granulocyte recruitment.
- Csk supports granulocyte motility by negatively regulating cell adhesion upon stimulation.