Verotoxin activates mitogen-activated protein kinase in human peripheral blood monocytes: role in apoptosis and proinflammatory cytokine release.
. In this study, we examined the role of mitogen-activated protein (MAP) kinases in the effects of verotoxins (VTs), from Escherichia coli O157:H7, upon both apoptosis and the release of tumour necrosis factor alpha (TNF-alpha) and granulocyte-macrophage colony-stimulated factor (GM-CSF) from human monocytes. 2. Both VT1 and VT2 stimulated a weak, transient increase in c-Jun-N-terminal kinase (JNK) activity and a strong activation of both p38 mitogen-activated protein kinase (MAP kinase) and extracellular-regulated kinase (ERK) activity in human monocytes, which was sustained in the case of p38 MAP kinase. 3. Stimulation of human monocytes with VT2 (100 ng ml-1) did not result in an increase in apoptosis; however, the toxin stimulated the release of both TNF-alpha and GM-CSF. 4. Pretreatment of human monocytes with the p38 MAP kinase inhibitor SB203580, at concentrations from 100 nM to 10 microM, significantly decreased the VT1- and VT2-induced TNF-alpha and GM-CSF release from monocytes. In contrast, inhibition of MEK1 with PD98059 only significantly decreased GM-CSF release. 5. Pretreatment of monocytes with SP600125 inhibited both GM-CSF and TNF-alpha production; however, significant effects upon p38 MAP kinase and ERK activation were observed. 6. Taken together, these results suggest a role for p38 MAP kinase and ERK in cytokine generation in response to the verotoxins. A role for JNK remains undetermined.
Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 ONR, Scotland. p.cameron@strath.ac.uk
Pamela
P
Cameron
Susan J
SJ
Smith
Mark A
MA
Giembycz
Dino
D
Rotondo
Robin
R
Plevin
D000873:Anthracenes / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D016207:Cytokines / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects*; D009000:Monocytes / Q000187:drug effects / Q000201:enzymology; D016755:Proto-Oncogene Proteins c-jun / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D022621:Shiga Toxin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
D000873:Anthracenes; D016207:Cytokines; D004791:Enzyme Inhibitors; D007093:Imidazoles; D016755:Proto-Oncogene Proteins c-jun; D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; C432165:pyrazolanthrone; D022621:Shiga Toxin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580