Inhibition of cyclin-dependent kinases by olomoucine and roscovitine reduces lipopolysaccharide-induced inflammatory responses via down-regulation of nuclear factor kappaB.
OBJECTIVE
Initiation and maintenance of pro-inflammatory reactions elicited by bacterial lipopolysaccharide and/or cytokines in the macrophage lineage have been reported to play a crucial role in acute and chronic pathogenic effects. Whether pro-inflammatory responses triggered by lipopolysaccharide in growth arrested cells differ from those in proliferating cells remains unanswered.


METHODS
Olomoucine and roscovitine are cyclin-dependent kinase (CDK) inhibitors that prevent progression through the cell cycle. After treatment with CDK inhibitors, expression of pro-inflammatory genes was analysed by reverse transcriptase-polymerase chain reaction. Protein levels of inducible nitric oxide synthase (iNOS) and nuclear factor kappaB (NF-kappaB) were determined by Western blotting. Promoter activity of iNOS was measured by the luciferase activity assay.


RESULTS
In this study we have demonstrated that both olomoucine and roscovitine inhibit cell proliferation and diminish nitric oxide production and cytokine gene expression, in lipopolysaccharide-stimulated murine RAW264.7 macrophages. In addition, olomoucine reduces iNOS promoter activity and alleviates NF-kappaB transcription activation. After co-transfection with E2F1 interference RNA, suppression of lipopolysaccharide-mediated iNOS promoter activity and NF-kappaB activation was observed. Furthermore, we demonstrated that olomoucine-induced growth arrested cells reduce expression of the p65 subunit of NF-kappaB.


CONCLUSIONS
The findings of this study suggest that inhibition of cell-cycle progression is capable of reducing pro-inflammatory responses via down-regulation of NF-kappaB.
Jhou
R-S
RS
Section of Urology, Cheng-Hsin Rehabilitation Medical Center, Taipei, Taiwan.
Sun
K-H
KH
Sun
G-H
GH
Wang
H-H
HH
Chang
C-I
CI
Huang
H-C
HC
Lu
S-Y
SY
Tang
S-J
SJ
D000818:Animals; D045744:Cell Line, Tumor; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D015536:Down-Regulation / Q000235:genetics; D050687:E2F1 Transcription Factor / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D007249:Inflammation / Q000378:metabolism*; D053582:Interleukin-1alpha / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D007701:Kinetin / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011687:Purines / Q000494:pharmacology; D034622:RNA Interference; D000077546:Roscovitine; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D050687:E2F1 Transcription Factor; C493754:E2f1 protein, mouse; D004791:Enzyme Inhibitors; D053582:Interleukin-1alpha; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011687:Purines; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D000077546:Roscovitine; D009569:Nitric Oxide; C090046:olomoucine; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D018844:Cyclin-Dependent Kinases; D007701:Kinetin