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Tec kinases regulate actin assembly and cytokine expression in LPS-stimulated human neutrophils via JNK activation

Rachel L Zemans1, Patrick G Arndt

  • 1Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Colorado School of Medicine, Denver, CO 80206, USA.

Cellular Immunology
|April 28, 2009
PubMed

Insights

Tec kinases are activated by lipopolysaccharide (LPS) in neutrophils, regulating inflammatory responses. Inhibiting Tec kinases reduces LPS-induced c-Jun NH(2)-terminal kinase (JNK) activity and inflammatory mediator release.

Area of Science:

  • Immunology
  • Cell Biology
  • Biochemistry

Background:

  • Neutrophils are key in acute inflammation, responding to bacterial products like lipopolysaccharide (LPS).
  • Mitogen-activated protein kinase (MAPK) c-Jun NH(2)-terminal kinase (JNK) is activated by LPS in neutrophils, influencing monocyte chemoattractant protein (MCP)-1 expression and actin assembly.
  • Tec family kinases regulate MAPK activation in various cell types and are present in neutrophils.

Purpose of the Study:

  • To investigate the role of Tec family kinases in LPS-induced MAPK activation in human neutrophils.
  • To determine if Tec kinases are upstream regulators of LPS-induced JNK and p38 activation.
  • To assess the dependence of LPS-induced inflammatory mediator expression and actin polymerization on Tec kinase activity.

Main Methods:

  • Stimulation of human neutrophils with LPS.
  • Inhibition of Tec kinases using leflunomide metabolite analog (LFM-A13).
  • Assessment of JNK and p38 MAPK activity via Western blotting.
  • Measurement of actin polymerization and expression of MCP-1, TNF-α, IL-6, and IL-1β.

Main Results:

  • Tec kinases are activated in LPS-stimulated human neutrophils.
  • Inhibition of Tec kinases with LFM-A13 decreased LPS-induced JNK activity, but not p38 activity.
  • LPS-induced actin polymerization and the expression of MCP-1, TNF-α, IL-6, and IL-1β were dependent on Tec kinase activity.

Conclusions:

  • Tec kinases are upstream activators of LPS-induced JNK signaling in neutrophils.
  • Tec kinase activity is crucial for LPS-mediated inflammatory responses, including cytokine production and actin remodeling.
  • Targeting Tec kinases may represent a therapeutic strategy for inflammatory conditions driven by LPS stimulation.

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