Stimulation of interleukin-8 production by okadaic acid and vanadate in a human promyelocyte cell line, an HL-60 subline. Possible role of mitogen-activated protein kinase on the okadaic acid-induced NF-kappaB activation.
Most types of cells can produce interleukin (IL)-8 in response to various inflammatory stimuli. To study the role of protein phosphatases in the signal transduction leading to IL-8 production, a subline of HL-60 (C-15) was treated with okadaic acid (OA) and sodium orthovanadate (VA), inhibitors of phosphoserine/phosphothreonine phosphatase and phosphotyrosine phosphatase, respectively. Both OA and VA dramatically increased IL-8 secretion up to 200-fold in the HL-60 cells. OA and VA stimulation was accompanied by a marked increase in IL-8 mRNA expression and also by activation of a transcription factor, NF-kappaB. In addition, an essential role of the NF-kappaB site in the IL-8 gene activation was confirmed by the chloramphenicol acetyltransferase assay. IL-8 production by OA or VA was inhibited by protein kinase inhibitors, including staurosporine, H-7, K252a, herbimycin A, and genistein. Both OA and VA induced significant tyrosine phosphorylation of p44, which was presumed to be Erk1, a member of the mitogen-activated protein kinase family, with concomitant activation of the mitogen-activated protein kinase activity. In parallel, rapid degradation of IkappaB-alpha, an inhibitory component of NF-kappaB, was observed. Since OA-activated Erk1 phosphorylated recombinant IkappaB-alpha in vitro, we assumed that Erk1 is involved in the phosphorylation and subsequent degradation of IkappaB-alpha, thus leading to the activation of IL-8 gene transcription.
Sonoda
Y
Y
Department of Biochemistry, Kyoritsu College of Pharmacy, Shibakoen, Minato-ku, Tokyo 105, Japan.
Kasahara
T
T
Yamaguchi
Y
Y
Kuno
K
K
Matsushima
K
K
Mukaida
N
N
D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004247:DNA; D018922:HL-60 Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D019319:Okadaic Acid / Q000494:pharmacology*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics; D014443:Tyrosine / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology*
D016209:Interleukin-8; D016328:NF-kappa B; D012333:RNA, Messenger; D019319:Okadaic Acid; D014638:Vanadates; D014443:Tyrosine; D004247:DNA; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases