Inhibition of lipopolysaccharide-induced expression of inducible nitric oxide synthase by phenolic (3E)-4-(2-hydroxyphenyl)but-3-en-2-one in RAW 264.7 macrophages.
The large amount of nitric oxide (NO) produced by inducible NO synthase (iNOS) contributes to cellular injury in inflammatory disease. In the present study, a novel synthetic compound (3E)-4-(2-hydroxyphenyl)but-3-en-2-one (HPB) was found to inhibit lipopolysaccharide (LPS)-induced NO generation, but not through the inhibition of iNOS activity, in RAW 264.7 macrophages. Administration of HPB into mice also inhibited the LPS-induced increase in serum nitrite/nitrate levels. To evaluate the underlying mechanisms of HPB inhibition of NO generation, the expression of the iNOS gene in RAW 264.7 macrophages was examined. HPB abolished the LPS-induced expression of iNOS protein, iNOS mRNA and iNOS promoter activity in a similar concentration-dependent manner. LPS-induced nuclear factor-kappaB (NF-kappaB) DNA binding and NF-kappaB-dependent reporter gene activity were both significantly inhibited by HPB. This effect was mediated through the inhibition of inhibitory factor-kappaBalpha (IkappaBalpha) phosphorylation and degradation, and of p65 nuclear translocation. HPB had no effect on the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinases (MAPK), and c-Jun NH(2)-terminal kinase (JNK). However, HPB suppressed the LPS-induced intracellular reactive oxygen species (ROS) production. These results indicate that HPB down-regulates iNOS gene expression probably through the inhibition of LPS-induced intracellular ROS production, which has been implicated in the activation of NF-kappaB.
Department of Education and Research, Taichung Veterans General Hospital, #160 Sec. 3 Chung Kang Road, Taichung 407, Taiwan, ROC.
Lo-Ti
LT
Tsao
Pei-Shan
PS
Tsai
Ruey-Hseng
RH
Lin
Li-Jiau
LJ
Huang
Sheng-Chu
SC
Kuo
Jih-Pyang
JP
Wang
D000818:Animals; D001483:Base Sequence; D002074:Butanones / Q000494:pharmacology*; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D010636:Phenols / Q000494:pharmacology*; D017382:Reactive Oxygen Species
C503827:4-(2-hydroxyphenyl)but-3-en-2-one; D002074:Butanones; D017931:DNA Primers; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010636:Phenols; D017382:Reactive Oxygen Species; D004247:DNA; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D020928:Mitogen-Activated Protein Kinases