8-isoprostane increases expression of interleukin-8 in human macrophages through activation of mitogen-activated protein kinases.
OBJECTIVE
8-isoprostane is a marker of oxidative stress in vivo and increased plasma and urine levels are found in patients with vascular disease and in atherosclerotic plaques. Inflammatory chemokines such as interleukin (IL)-8 seem to play an important pathogenic role in atherogenesis. We therefore investigated the effects of 8-isoprostane on the expression of inflammatory chemokines with consciousness on IL-8 (mRNA and protein) in human macrophages. In addition, we studied the involvement of mitogen-activated protein kinases (ERK 1/2 and p38 MAPK) and nuclear factor-kappaB (NF-kappaB) in this process.


RESULTS
8-isoprostane (10 microM) induced IL-8 expression (mRNA and protein), measured by real-time quantitative RT-PCR and enzyme immunoassay, respectively, in both THP-1 macrophages and human monocyte-derived macrophages. Moreover, 8-isoprostane increased mRNA expression of macrophage inflammatory protein-1alpha as determined by RNase protection assay. In this process, 8-isoprostane induced the activation of two major MAP-kinases; ERK 1/2 and p38 MAPK. Furthermore, the ERK 1/2 inhibitor, PD98059, and the p38 MAPK inhibitor, SB203580, markedly reduced 8-isoprostane-induced IL-8 expression (mRNA and protein), while inhibition of NF-kappaB activation and translocation had no significant effect on IL-8 expression.


CONCLUSIONS
We show that 8-isoprostane increases IL-8 expression in human macrophages involving both ERK 1/2 and p38 MAPK, but not NF-kappaB signaling pathway. These findings further support a link between oxidative stress/lipid peroxidation and inflammation in human macrophages and suggest a role for 8-isoprostane in this process. This 8-isoprostane-induced chemokine expression might be involved in the pathogenesis of atherosclerosis as well as other inflammatory disorders.
Scholz
Hanne
H
Research Institute for Internal Medicine, The National Hospital, University of Oslo, Sognsvannsveien 20, N-0027 Oslo, Norway. hanne.schulz@klinmed.uio.no
Yndestad
Arne
A
Damås
Jan Kristian
JK
Waehre
Torgun
T
Tonstad
Serena
S
Aukrust
Pål
P
Halvorsen
Bente
B
D002460:Cell Line; D002478:Cells, Cultured; D015237:Dinoprost / Q000031:analogs & derivatives*; D004789:Enzyme Activation; D028441:F2-Isoprostanes / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007249:Inflammation; D016209:Interleukin-8 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D048051:p38 Mitogen-Activated Protein Kinases
D028441:F2-Isoprostanes; D016209:Interleukin-8; D012333:RNA, Messenger; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases