interleukin-8 and 1-3-dimethylthiourea

The relationship of cytokine production and reactive oxygen species (ROS) generated in mast cells has not been reported yet. This study aimed to examine the signal pathway in the production of cytokines [interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha)] by ROS generated from phorbol myristate acetate (PMA)-stimulated human mast cell line-1 cells (HMC-1). HMC-1 cells were stimulated with 25 ng/ml of PMA. The ROS generation and production of cytokines (IL-8 and TNF-alpha) were measured by fluorescence-activated cell sorter and enzyme-linked immunosorbent assay method, respectively. Phosphorylation of mitogen-activated protein kinase family (extracellular signal-regulated kinase, p38 and c-Jun N-terminal kinase) was detected by the Western blotting method. The expression of cytokine's mRNA was measured by reverse transcriptase--polymerase chain reaction, and the DNA-binding activity of the transcription factors [nuclear factor-kappaB (NF-kappaB) and activator protein-1] was detected by electrophoretic mobility shift assay. PMA-stimulated HMC-1 cells immediately generated ROS, and the generated ROS was inhibited by 1,3-dimethyl-2-thiourea (DMTU), but partially inhibited by catalase or N-acetyl-L-cysteine. The production of cytokines in PMA-stimulated HMC-1 cells reached the maximum at 3-5 h and was inhibited by DMTU and specific kinase inhibitor for p38, SB203580. DMTU and SB203580 also inhibited the expressed cytokine's mRNA level and the increased DNA-binding activity of transcription factors, NF-kappaB in PMA-stimulated HMC-1 cells. These data suggest that intracellular ROS generated from PMA-stimulated HMC-1 cells contributes to the production of inflammatory cytokines via p38 kinase/NF-kappaB.

Topics: Antioxidants; Free Radical Scavengers; Humans; Imidazoles; Interleukin-8; JNK Mitogen-Activated Protein Kinases; Mast Cells; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinase Inhibitors; Pyridines; Reactive Oxygen Species; RNA, Messenger; Signal Transduction; Tetradecanoylphorbol Acetate; Thiourea; Transcription Factors; Tumor Necrosis Factor-alpha

The present study aims at investigating the effects of mannitol and dimethylthiourea, known hydroxyl radical scavengers, on lipid peroxidation as an indicative of oxidative damage, NF-kappa B activation and IL-8 production by Helicobacter pylori in gastric epithelial cells. A human gastric epithelial cell line, AGS, treated with or without mannitol and dimethylthiourea, was incubated in the absence or the presence of H. pylori. As a result, H. pylori significantly stimulated the productions of lipid peroxide and IL-8. Treatment with H. pylori resulted in the activation of two species of NF-kappa B dimers (a p50/p65 heterodimer and a p50 homodimer). Mannitol and dimethylthiourea significantly inhibited lipid peroxide production, NF-kappa B complex formation and IL-8 production by H. pylori. In conclusion, mannitol and dimethylthiourea may attenuate H. pylori-induced gastric inflammation by inhibiting lipid peroxidation and NF-kappa B activation and thereby decreasing IL-8 production.

Topics: Cell Line; Cytokines; Diuretics, Osmotic; Electrophoresis; Epithelial Cells; Free Radical Scavengers; Gastric Mucosa; Helicobacter Infections; Helicobacter pylori; Humans; Hydroxyl Radical; Interleukin-8; Lipid Peroxidation; Mannitol; NF-kappa B; Thiourea

Despite the many epidemiological studies supporting the contention that ambient air pollution particles can adversely affect human health, there is no clear agreement as to a biologically plausible mechanism which can explain the acute mortality and morbidity associated with exposure to particles less than 10 microm in size. We tested the hypothesis that metals present in an air pollution particle can induce the synthesis and expression of the inflammatory cytokines IL-8, IL-6, and TNFalpha. A residual oil fly ash (ROFA) containing the transition metals vanadium, nickel, and iron was used as a model emission source air pollution particle. Normal human bronchial epithelial (NHBE) cells were exposed for either 2 or 24 hr to 0, 5, 50, or 200 microg/ml ROFA. Concentrations of IL-8, IL-6, and TNF-alpha proteins were measured with commercially available ELISA kits. mRNA for these same cytokines was quantified by RT-PCR. NHBE cells exposed to ROFA produced significant amounts of IL-8, IL-6, and TNF, as well as mRNAs coding for these cytokines. Cytokine production was inhibited by the inclusion of either the metal chelator deferoxamine (1.0 mM) or the free radical scavenger dimethylthiourea (1.0 mM). In addition, vanadium containing compounds, but not iron or nickel sulfates, mimicked the effects of intact ROFA. These results demonstrate that metals present in ROFA may be responsible for production and release of inflammatory mediators by the respiratory tract epithelium and suggest that these mediators may contribute to the toxic effects of particulate air pollutants reported in epidemiology studies.

Topics: Air Pollutants, Occupational; Bronchi; Carbon; Cells, Cultured; Chelating Agents; Coal Ash; Cytokines; Deferoxamine; Epithelial Cells; Free Radical Scavengers; Humans; Interleukin-6; Interleukin-8; Iron; Metals; Nickel; Particle Size; Particulate Matter; RNA, Messenger; Thiourea; Tumor Necrosis Factor-alpha; Vanadium