Involvement of the extracellular signal regulated kinase pathway in hydrocarbon-induced reactive oxygen species formation in human neutrophil granulocytes.
In the present study we have examined the effects of hydrocarbons on the formation of reactive oxygen species (ROS) in human neutrophil granulocytes in vitro. We found that hydrocarbons induce ROS formation in a concentration-dependent manner and that the ROS-inducing potency increases with increasing number of carbon atoms in the structure. In general, aromatic hydrocarbons were less potent inducers of ROS than aliphatic and cyclic hydrocarbons. The most potent compound in each group, t-butylcyclohexane, n-decane, and n-butylbenzene, were chosen for mechanistic studies. ROS formation was inhibited by the MEK1/2 inhibitor U0126, the tyrosine kinase inhibitor erbstatin-A, and the phosphatidylinositol-3 kinase inhibitor wortmannin. The involvement of the ERK1/2 pathway was confirmed by Western blot analysis of phosphorylated ERK1/2. The study revealed only small differences in the mechanisms involved for the three compounds. The responses were not affected by Pertussis toxin, indicating that Gi-protein coupled receptors are not involved in neutrophil activation after hydrocarbon exposure. Based on these findings we propose a mechanism involving tyrosine kinases, PI3 kinase, and the ERK1/2 pathway, leading to activation of the NADPH oxidase and production of ROS in neutrophils stimulated by organic solvents.
Dreiem
Anne
A
Norwegian Defence Research Establishment, Division for Protection and Materiel, Kjeller, Norway. anne.dreiem@ffi.no
Myhre
Oddvar
O
Fonnum
Frode
F
D000328:Adult; D015153:Blotting, Western; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D006801:Humans; D006838:Hydrocarbons / Q000737:chemistry / Q000633:toxicity*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology*; D037342:Pertussis Toxin / Q000494:pharmacology; D021281:Quantitative Structure-Activity Relationship; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012997:Solvents / Q000737:chemistry / Q000633:toxicity
D006838:Hydrocarbons; D017382:Reactive Oxygen Species; D012997:Solvents; D037342:Pertussis Toxin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go