Premium
The anti‐inflammatory carbazole, LCY‐2‐CHO, inhibits lipopolysaccharide‐induced inflammatory mediator expression through inhibition of the p38 mitogen‐activated protein kinase signaling pathway in macrophages
Author(s) -
Ho FengMing,
Lai ChihChang,
Huang LiJiau,
Kuo Tsun Cheng,
Chao Chien M,
Lin WanWan
Publication year - 2004
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0705700
Subject(s) - p38 mitogen activated protein kinases , microbiology and biotechnology , mapk/erk pathway , nitric oxide synthase , tumor necrosis factor alpha , kinase , protein kinase a , biology , signal transduction , chemistry , nitric oxide , immunology , endocrinology
The present study was undertaken to investigate the anti‐inflammatory effects of a synthetic compound, LCY‐2‐CHO, on the expression of inducible nitric oxide synthase (iNOS), COX‐2, and TNF‐ α in murine RAW264.7 macrophages. Within 1–30 μ M , LCY‐2‐CHO concentration‐dependently inhibited lipopolysaccharide (LPS)‐induced nitric oxide (NO), prostaglandin E 2 (PGE 2 ), and tumor necrosis factor‐ α (TNF‐ α ) formation, with IC 50 values of 2.3, 1, and 0.8 μ M , respectively. Accompanying inhibition of LPS‐induced iNOS, cyclooxygenase‐2 (COX‐2), and pro‐TNF‐ α proteins was observed. Reverse transcription‐polymerase chain reaction (RT–PCR) and promoter analyses indicated that iNOS expression was inhibited at the transcriptional level (IC 50 =2.3 μ M ), that inhibition of COX‐2 expression only partially depended on gene transcription (IC 50 =7.6 μ M ), and that TNF‐ α transcription was unaffected. Transcriptional assays revealed that activation of AP‐1, but not NF‐ κ B, was concomitantly blocked by LCY‐2‐CHO. Our results showed that LCY‐2‐CHO was capable of interfering with post‐transcriptional regulation, altering the stability of COX‐2 and TNF‐ α mRNAs. Since the 3′‐untranslated region (3′ UTR) of both COX‐2 and TNF‐ α mRNA contains a p38 mitogen‐activated protein kinase (MAPK)‐regulated element involved in mRNA stability, we assessed the effect of LCY‐2‐CHO on p38 MAPK. Our data clearly indicated an inhibition (IC 50 =1.7 μ M ) of LPS‐mediated p38 MAPK activity, but not of extracellular signal‐regulated kinase (ERK) or c‐Jun N‐terminal kinase (JNK) activity. However, kinase assays ruled out a direct inhibition of p38 MAPK action. The selective p38 MAPK inhibitor, SB203580, inhibited the promoter activities of iNOS and COX‐2 rather than that of TNF‐ α . In conclusion, LCY‐2‐CHO downregulates inflammatory iNOS, COX‐2, and TNF‐ α gene expression in macrophages through interfering with p38 MAPK and AP‐1 activation.British Journal of Pharmacology (2004) 141 , 1037–1047. doi: 10.1038/sj.bjp.0705700