Integrin-linked kinase regulates inducible nitric oxide synthase and cyclooxygenase-2 expression in an NF-kappa B-dependent manner

J Biol Chem. 2002 Feb 1;277(5):3109-16. doi: 10.1074/jbc.M108673200. Epub 2001 Nov 27.

Abstract

Nitric oxide (NO) and prostaglandins are produced as a result of the stimulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2, respectively, in response to cytokines or lipopolysaccharide (LPS). We demonstrate that the activity of integrin-linked kinase (ILK) is stimulated by LPS activation in J774 macrophages. Inhibition of ILK activity by dominant-negative ILK or a highly selective small molecule ILK inhibitor, in epithelial cells or LPS-stimulated J774 cells and murine macrophages, resulted in inhibition of iNOS expression and NO synthesis. LPS stimulates the phosphorylation of IkappaB on Ser-32 and promotes its degradation. Inhibition of ILK suppressed this LPS-stimulated IkappaB phosphorylation and degradation. Similarly, ILK inhibition suppressed the LPS-stimulated iNOS promoter activity. Mutation of the NF-kappaB sites in the iNOS promoter abolished LPS- and ILK-mediated regulation of iNOS promoter activity. Overexpression of ILK-stimulated NF-kappaB activity and inhibition of ILK or protein kinase B (PKB/Akt) suppressed this activation. We conclude that ILK can regulate NO production in macrophages by regulating iNOS expression through a pathway involving PKB/Akt and NF-kappaB. Furthermore, we also demonstrate that ILK activity is required for LPS stimulated cyclooxygenase-2 expression in murine and human macrophages. These findings implicate ILK as a potential target for anti-inflammatory applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • Gene Expression Regulation, Enzymologic*
  • Humans
  • Isoenzymes / genetics*
  • Lipopolysaccharides / pharmacology
  • Macrophages
  • Membrane Proteins
  • Mice
  • NF-kappa B / metabolism*
  • Nitric Oxide Synthase / genetics*
  • Nitric Oxide Synthase Type II
  • Phosphorylation
  • Promoter Regions, Genetic / drug effects
  • Prostaglandin-Endoperoxide Synthases / genetics*
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Recombinant Fusion Proteins / metabolism

Substances

  • Isoenzymes
  • Lipopolysaccharides
  • Membrane Proteins
  • NF-kappa B
  • Recombinant Fusion Proteins
  • NOS2 protein, human
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • PTGS1 protein, human
  • PTGS2 protein, human
  • Prostaglandin-Endoperoxide Synthases
  • Ptgs1 protein, mouse
  • integrin-linked kinase
  • Protein Serine-Threonine Kinases