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Updated: Oct 23, 2026

Isolation and In vitro Culture of Bone Marrow-Derived Macrophages for the Study of NO-Redox Biology
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Isolation and In vitro Culture of Bone Marrow-Derived Macrophages for the Study of NO-Redox Biology

Published on: May 31, 2022

Negative regulation by phosphatidylinositol 3-kinase of inducible nitric oxide synthase expression in macrophages

M J Díaz-Guerra1, A Castrillo, P Martín-Sanz

  • 1Instituto de Bioquímica, Facultad de Farmacia, 28040 Madrid, Spain.

Journal of Immunology (Baltimore, Md. : 1950)
|May 7, 1999
PubMed

Insights

Phosphatidylinositol 3-kinase (PI3-kinase) negatively regulates macrophage activation. Inhibiting PI3-kinase increases nitric oxide production and enhances NF-kappaB activation, suggesting a role in anti-inflammatory cytokine action.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • Lipopolysaccharide (LPS) transiently activates phosphatidylinositol 3-kinase (PI3-kinase) in RAW 264.7 macrophages.
  • Macrophage activation involves complex signaling pathways influencing inflammatory responses.

Purpose of the Study:

  • To investigate the role of PI3-kinase in modulating macrophage activation by LPS.
  • To determine PI3-kinase's influence on inducible nitric oxide synthase (iNOS) and NF-kappaB signaling.

Main Methods:

  • RAW 264.7 macrophage cell line stimulation with LPS.
  • Inhibition of PI3-kinase using wortmannin and LY294002.
  • Measurement of iNOS and nitric oxide synthesis.
  • NF-kappaB activation assays and iNOS promoter activity analysis via transfection.

Main Results:

  • PI3-kinase inhibition by wortmannin and LY294002 increased iNOS expression and nitric oxide production.
  • Wortmannin treatment prolonged NF-kappaB activation and enhanced iNOS gene promoter activity.
  • Modulating PI3-kinase catalytic activity affected iNOS promoter responsiveness to LPS and wortmannin.

Conclusions:

  • PI3-kinase acts as a negative regulator in LPS-induced macrophage activation.
  • These findings suggest PI3-kinase is involved in the mechanism of anti-inflammatory cytokines.

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