Suppression of the NF-kappaB signalling pathway by ergolide, sesquiterpene lactone, in HeLa cells.
We have previously reported that ergolide, a sesquiterpene lactone isolated from Inula britannica, suppresses inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression by inhibiting nuclear factor-kappaB (NF-kappaB) in RAW 264.7 macrophages. In this study, we show that ergolide suppresses the DNA binding activity of NF-kappaB and nuclear translocation of NF-kappaB p65 subunit, leading to the inhibition of NF-kappaB-dependent gene transcription in 12-O-tetradecanoylphorbol 13acetate (TPA)-stimulated HeLa cells. We also show that ergolide decreases the degradation and phosphorylation of IkappaB, an inhibitory protein of NF-kappaB, and this effect is accompanied by a simultaneous reduction of IkappaB kinase (IKK) activity. However, ergolide does not inhibit in-vitro IKK activity directly, suggesting the possible involvement of upstream IKK kinases in the regulation of NF-kappaB activation. Furthermore, ergolide-mediated protein kinase Calpha (PKCalpha) inhibition is involved in reduction of NF-kappaB inhibition, as demonstrated by the observation that dominant negative PKCalpha, but not p44/42 MAPK and p38 MAPK, inhibits TPA-stimulated reporter gene expression. Taken together, our results suggest that ergolide suppresses NF-kappaB activation through the inhibition of PKCalpha-IKK activity, providing insight for PKCalpha as a molecular target for anti-inflammatory drugs.
Chun
Jae Kwang
JK
College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Seo
Dong-Wan
DW
Ahn
Seong Hoon
SH
Park
Jae Hyun
JH
You
Jueng-Soo
JS
Lee
Chang-Hee
CH
Lee
Jae Cheol
JC
Kim
Yong Kee
YK
Han
Jeung-Whan
JW
D004247:DNA / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D020672:I-kappa B Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D038143:Inula / Q000737:chemistry*; D007783:Lactones / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D051571:Protein Kinase C-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D012717:Sesquiterpenes / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate; D051996:Transcription Factor RelA / Q000037:antagonists & inhibitors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D020672:I-kappa B Proteins; D007783:Lactones; D016328:NF-kappa B; D012717:Sesquiterpenes; D051996:Transcription Factor RelA; C099797:ergolide; D004247:DNA; D051550:I-kappa B Kinase; D051571:Protein Kinase C-alpha; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate