Chlorophyllin suppresses interleukin-1 beta expression in lipopolysaccharide-activated RAW 264.7 cells.
Our previous findings demonstrated that chlorophyllin (CHL) inhibits inducible nitric oxide gene expression in macrophages. In the present study, we show that CHL inhibited IL-1beta production and its mRNA expression in a lipopolysaccharide (LPS)-stimulated murine macrophage cell-line, RAW 264.7. The inhibitory effect of CHL on IL-1beta gene expression was further supported by an in vitro transfection assay using a pIL-1(870 bp)-CAT construct, where CHL inhibited the activation of the IL-1beta promoter. Furthermore, CHL attenuated the activation of NF-kappaB, NF-IL6 and AP-1, which are known to be responsible for IL-1beta gene expression, as determined by an electrophoretic mobility shift assay and an in vitro transfection assay using p(NF-kappaB)3-CAT, p(NF-IL6)3-CAT, and p(AP-1)3-CAT, respectively. However, it was evident that the inhibitory activity of CHL on IL-1beta expression in the LPS-stimulated macrophages was independent of CRE/ATF. The immunoblot experiment demonstrated that CHL also caused a substantial decrease in the phosphorylation of p38 MAP kinase in LPS-stimulated RAW 264.7. These results suggest that CHL inhibits IL-1beta production in macrophages stimulated with LPS at transcriptional level by blocking the phosphorylation of p38 and by suppressing the activation of transcription factors, NF-kappaB, NF-IL6, and AP-1.
Yun
Cheol-Heui
CH
International Vaccine Institute, Seoul, 151-818, Republic of Korea.
Jeon
Young Jin
YJ
Yang
Young
Y
Ju
Hyang Ran
HR
Han
Seung Hyun
SH
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D002735:Chlorophyllides / Q000494:pharmacology*; D003864:Depression, Chemical; D015536:Down-Regulation / Q000187:drug effects; D024202:Electrophoretic Mobility Shift Assay; D007202:Indicators and Reagents; D007375:Interleukin-1 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D010766:Phosphorylation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics
D002735:Chlorophyllides; D007202:Indicators and Reagents; D007375:Interleukin-1; D008070:Lipopolysaccharides; D015500:Chloramphenicol O-Acetyltransferase; D048051:p38 Mitogen-Activated Protein Kinases; C007020:chlorophyllin