Inhibition of nitric oxide production by the carbazole compound LCY-2-CHO via blockade of activator protein-1 and CCAAT/enhancer-binding protein activation in microglia.
Excessive nitric oxide (NO) production by activated microglia plays a critical role in neurodegenerative disorders. In this study, we found that 9-(2-chlorobenyl)-9H-carbazole-3-carbaldehyde (LCY-2-CHO) suppressed the NO production in lipopolysaccharide (LPS)/interferon-gamma (IFNgamma)-stimulated murine microglial N9 and BV-2 cells and in LPS-stimulated N9 cells and rat primary microglia. LCY-2-CHO had no cytotoxic effect on microglia. In activated N9 cells, LCY-2-CHO abolished the expression of inducible nitric oxide synthase (iNOS) protein and mRNA but failed to alter the stability of expressed iNOS mRNA and the enzymatic activity of expressed iNOS protein. LCY-2-CHO did not block DNA-binding activity of nuclear factor-kappaB (NF-kappaB) or cyclic AMP response element-binding protein (CREB), but abolished that of activator protein-1 (AP-1), CCAAT/enhancer-binding protein (C/EBP) and nuclear factor IL6 (NF-IL6). LCY-2-CHO attenuated the nuclear levels of c-Jun and C/EBPbeta, but not those of p65, p50, C/EBPdelta, signal transducer and activator of transcription-1 (STAT-1) or the nuclear expression of IFN regulatory factor-1 (IRF-1). LCY-2-CHO had no effect on the phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), MAPK-activated protein kinase-2 (MAPKAPK-2), STAT-1, CREB or c-Jun in LPS/IFNgamma-stimulated N9 cells, whereas it attenuated the phosphorylation of C/EBPbeta at Ser105 and Thr235 residues, which occurred concomitantly with LCY-2-CHO inhibition of C/EBPbeta expression and phosphorylation. Taken together, these results suggest that LCY-2-CHO inhibits NO production in microglia through the blockade of AP-1 and C/EBP activation.
Chang
Ling-Chu
LC
Institute of Medicine, Chung Shan Medical University, Taichung 403, Taiwan, ROC.
Tsao
Lo-Ti
LT
Chang
Chi-Sen
CS
Chen
Chun-Jung
CJ
Huang
Li-Jiau
LJ
Kuo
Sheng-Chu
SC
Lin
Ruey-Hseng
RH
Wang
Jih-Pyang
JP
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D022762:CCAAT-Enhancer-Binding Proteins / Q000037:antagonists & inhibitors*; D002227:Carbazoles / Q000494:pharmacology*; D002478:Cells, Cultured; D007371:Interferon-gamma / Q000009:adverse effects; D008070:Lipopolysaccharides / Q000009:adverse effects; D051379:Mice; D017628:Microglia / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D009687:Nuclear Proteins / Q000187:drug effects; D012333:RNA, Messenger / Q000187:drug effects; D051381:Rats; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors*
C499102:9-(2-chlorobenzyl)-9H-carbazole-3-carbaldehyde; D000893:Anti-Inflammatory Agents; D022762:CCAAT-Enhancer-Binding Proteins; D002227:Carbazoles; D008070:Lipopolysaccharides; D009687:Nuclear Proteins; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D009569:Nitric Oxide; D007371:Interferon-gamma; D052247:Nitric Oxide Synthase Type II