Anti-malarial agent artesunate inhibits TNF-alpha-induced production of proinflammatory cytokines via inhibition of NF-kappaB and PI3 kinase/Akt signal pathway in human rheumatoid arthritis fibroblast-like synoviocytes.
OBJECTIVE
Recent studies indicate that the anti-malarial agent artemisinin and its derivatives may exert an anti-inflammatory effect. In this study, we explored the effect of artesunate, an artemisinin derivative, on tumour necrosis factor (TNF)-alpha-induced production of interleukins, IL-1beta, IL-6 and IL-8, in human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS), and further investigated the signal mechanism by which this compound modulates those cytokines' production.


METHODS
RA FLS obtained from patients with active RA were stimulated with TNF-alpha and incubated with artesunate, and IL-1beta, IL-6 and IL-8 production was measured by ELISA. DNA-binding activity and nuclear translocation of nuclear factor kappa B (NF-kappaB) were measured by a sensitive multi-well colourimetric assay and confocal fluorescence microscopy, respectively. Signal transduction proteins expression was measured by western blot.


RESULTS
Artesunate decreased the secretion of IL-1beta, IL-6 and IL-8 from TNF-alpha-stimulated RA FLS in a dose-dependent manner. Artesunate also prevented TNF-alpha-induced nuclear NF-kappaB translocation, DNA-binding activity and gene transcriptional activity, as well as phosphorylation and degradation of IkappaBalpha, but phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase and c-Jun N-terminal kinase were unaffected. The production of IL-1beta, IL-6 and IL-8 induced by TNF-alpha was decreased by pyrrolidine dithiocarbamate (PDTC), a chemical inhibitor of NF-kappaB. These observations suggest that artesunate inhibits production of IL-1beta, IL-6 and IL-8 through inhibition of NF-kappaB signalling pathway. We also showed that artesunate prevented Akt phosphorylation. TNF-alpha-induced production of IL-1beta, IL-6 and IL-8 was hampered by treatment with the phosphatidylinositol 3 (PI3) kinase inhibitor LY294002, suggesting that inhibition of Akt activation might inhibit IL-1beta, IL-6 and IL-8 production induced by TNF-alpha.


CONCLUSIONS
Our results indicate that artesunate exerts an anti-inflammatory effect in RA FLS and provide the evidence that artesunate may have therapeutic potential for RA.
Xu
H
H
Department of Rheumatology, The First Affiliated Hospital, SUN Yat-sen University, Guangzhou, Guangdong 510080, PR China. xuhanshi@hotmail.com
He
Y
Y
Yang
X
X
Liang
L
L
Zhan
Z
Z
Ye
Y
Y
Yang
X
X
Lian
F
F
Sun
L
L
D000368:Aged; D000962:Antimalarials / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology*; D000077332:Artesunate; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D053492:Elafin / Q000502:physiology; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D008875:Middle Aged; D016328:NF-kappa B / Q000235:genetics / Q000502:physiology; D012717:Sesquiterpenes / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000494:pharmacology
D000962:Antimalarials; D037621:Artemisinins; D016207:Cytokines; D053492:Elafin; D018836:Inflammation Mediators; D016328:NF-kappa B; C506806:PI3 protein, human; D012717:Sesquiterpenes; D014409:Tumor Necrosis Factor-alpha; D000077332:Artesunate