Lipopolysaccharide-induced expression of cyclooxygenase-2 in mouse macrophages is inhibited by chloromethylketones and a direct inhibitor of NF- κB translocation

Aida Abate, Stefanie Oberle, Henning Schroeder

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41 Scopus citations

Abstract

In macrophages, cyclooxygenase-2 (COX-2) is induced by cytokines, mitogens, or endotoxin. The present study investigates whether inhibitors of the nuclear transcription factor NF-κB affect lipopolysaccharide (LPS)- mediated expression of COX-2 mRNA, protein, and activity in the macrophage cell line J774.1A. The activation of COX-2 was assessed by measuring the accumulation of prostaglandin (PG) E2 by radioimmunoassay. Expression of COX-2 mRNA and protein was detected by Northern and Western blot analysis, respectively. In the absence of LPS, mouse macrophages did not express COX-2 and generated low amounts of prostaglandin (PC) E2. Treatment of J774.1A with LPS (0. 1-30 μg/ml) caused expression of COX-2 protein and activity. Induction of COX-2 activity along with the induction of COX-2 mRNA and protein by LPS was attenuated by the serine protease inhibitors N-α-tosyl- L-phenylalanine chloromethyl ketone (TPCK) and N-α-tosyl-L-lysine chloromethyl ketone (TLCK). A cell permeable peptide and a direct inhibitor of NF-κB translocation, SNSO, attenuated the accumulation of PGE2 in cell supernatant in a concentration-dependent manner. Our results show that induction of COX-2 by LPS in macrophages involves activation of NF-κB and point to a possible therapeutic use of protease inhibitors in inflammatory processes.

Original languageEnglish (US)
Pages (from-to)277-290
Number of pages14
JournalProstaglandins and Other Lipid Mediators
Volume56
Issue number5-6
DOIs
StatePublished - Dec 1 1998
Externally publishedYes

Keywords

  • Chloromethylketones
  • Inflammation
  • Lipopolysaccharide
  • Macrophages
  • NF-κB

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