interleukin-8 and pimagedine

Recent studies indicate that nitric oxide (NO) or related compounds may regulate the production of interleukin (IL)-8, a potent proinflammatory chemokine. Here we report that peroxynitrite (ONOO(-)) formed by a reaction of NO with superoxide mediates IL-8 gene expression and IL-8 production in IL-1beta- and TNF-alpha-stimulated human leukocytes in whole blood. The NO synthase inhibitors aminoguanidine and N(G)-nitro-L-arginine methyl ester blocked nuclear accumulation of activator protein-1 (AP-1) and nuclear factor (NF)-kappaB in both polymorphonuclear (PMN) and mononuclear leukocytes and inhibited IL-8 mRNA expression and IL-8 release by approximately 90% in response to IL-1beta and TNF-alpha. Enhanced ONOO(-) formation was detected in granulocytes, monocytes, and lymphocytes after challenge with IL-1beta or TNF-alpha. The addition of ONOO(-) (0.2-80 microM) to whole blood increased nuclear accumulation of AP-1 and NF-kappaB in PMN and mononuclear leukocytes and augmented IL-8 mRNA expression and IL-8 production in a concentration-dependent fashion. Pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB activation, attenuated approximately 70% of IL-8 release evoked by IL-1beta, TNF-alpha, or ONOO(-). These results indicate that ONOO(-) formation may underlie the action of cytokines towards IL-8 gene expression in human leukocytes.

Topics: Antioxidants; Cell Nucleus; Cells, Cultured; Gene Expression; Guanidines; Humans; Interleukin-1; Interleukin-8; Leukocytes, Mononuclear; NF-kappa B; NG-Nitroarginine Methyl Ester; Nitrates; Nitric Oxide Synthase; Pyrrolidines; RNA, Messenger; Thiocarbamates; Transcription Factor AP-1; Tumor Necrosis Factor-alpha

Cardiopulmonary bypass (CPB) increases nitric oxide (NO) production by the activation of NO synthases (NOS). However, the role of NO from inducible NOS (iNOS) in CPB-induced inflammatory response remains unclear. We examined the effect of a selective iNOS inhibitor, aminoguanidine, on CPB-induced inflammatory response in a rat-CPB model.. Adult Sprague-Dawley rats underwent 60 minutes of CPB (100 mL x kg(-1) x min(-1), 34 degrees C). Group A (n = 10) received 100 mg/kg of aminoguanidine intraperitoneally 30 minutes before the initiation of CPB, and group B (n = 10) served as controls.. There were significant time-dependent changes in plasma interleukin (IL)-6, IL-8, nitrate + nitrite, the percentage ratio of nitrotyrosine to tyrosine (%NO2-Tyr, an indicator of peroxynitrite formation), and respiratory index (RI). Three hours after CPB termination, IL-6, IL-8, and RI were significantly higher in group A (IL-6, 397.5+/-80.6 pg/mL; IL-8, 26.99+/-6.57 ng/mL; RI, 1.87+/-0.31) than in group B (IL-6, 316.5+/-73.9 pg/mL, p <0.05; IL-8, 17.21+/-3.12 ng/mL, p < 0.01; RI, 1.57+/-0.24, p < 0.05) although nitrate + nitrite (31.8+/-4.1 micromol/L) and %NO2-Tyr (1.15%+/-0.20%) were significantly lower in group A than in group B (nitrate + nitrite, 50.2+/-5.0 micromol/L, p < 0.01; %NO2-Tyr, 1.46%+/-0.21%, p < 0.01). Western immunoblot analysis from lung tissue of group A identified marked iNOS inhibition without inhibiting endothelial-constitutive NOS, and neutrophil accumulation in the lung specimens was significantly greater in group A (6.5+/-0.7/alveoli) than in group B (4.4+/-0.4/alveoli, p < 0.01).. These results suggest that NO production from iNOS may be an adaptive response for attenuating the CPB-induced inflammatory response.

Topics: Animals; Cardiopulmonary Bypass; Endothelium, Vascular; Enzyme Induction; Guanidines; Interleukin-6; Interleukin-8; Male; Nitric Oxide; Nitric Oxide Synthase; Rats; Rats, Sprague-Dawley; Systemic Inflammatory Response Syndrome

Nitric oxide (NO) is increased in exhaled air of asthmatics. We hypothesized that endogenous NO contributes to airway inflammation and hyperresponsiveness, and that interleukin-8 (IL-8) might be involved in this mechanism. In human transformed bronchial epithelial cells in vitro, NO donors increased IL-8 production dose-dependently. In addition, tumor necrosis factor-alpha (TNF-alpha) plus IL-1beta plus interferon-gamma (IFN-gamma) increased IL-8 in culture supernatant of epithelial cells; the combination of NO synthase (NOS) inhibitors, aminoguanidine (AG) plus N(G)-nitro-L-arginine methyl ester (L-NAME) attenuated the cytokine-induced IL-8 production in epithelial cells. In guinea pigs in vivo, ozone exposure induced airway hyperresponsiveness to acetylcholine and increased neutrophils in bronchoalveolar lavage fluid (BALF), and these changes persisted for at least 5 h. Pretreatment with NOS inhibitors had no effect on airway hyperresponsiveness or neutrophil accumulation immediately after ozone, but significantly inhibited the changes 5 h after ozone. NOS inhibitors also attenuated the increases of nitrite/nitrate levels in BALF and the IL-8 mRNA expression in epithelial cells and in neutrophils in guinea pig airways 5 h after ozone. These results suggest that endogenous NO may play an important role in the persistent airway inflammation and hyperresponsiveness after ozone exposure, presumably partly through the upregulation of IL-8.

Topics: Acetylcholine; Animals; Blotting, Northern; Bronchi; Bronchial Hyperreactivity; Bronchitis; Bronchoalveolar Lavage Fluid; Cells, Cultured; DNA Primers; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Epithelial Cells; Guanidines; Guinea Pigs; Humans; In Situ Hybridization; Interleukin-8; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; omega-N-Methylarginine; Ozone; RNA, Messenger

Recent evidence indicates that free oxygen radicals, in particular hydroxyl radicals, may act as intracellular second messengers for the induction of IL-8, a potent chemoattractant and activator of neutrophil granulocytes. Here we report that peroxynitrite (ONOO-), formed by a reaction of nitric oxide (NO) with superoxide, mediates IL-8 gene expression and IL-8 production in LPS-stimulated human whole blood. The NO synthase inhibitors aminoguanidine and NG-nitro-L-arginine methyl ester (L-NAME) blocked IL-8 release by approximately 90% in response to LPS (1 microg/ml), but did not affect the production of IL-1beta or TNF-alpha. Both aminoguanidine and L-NAME blocked the induction of IL-8 mRNA by LPS. Authentic ONOO- (2.5-80 microM) augmented IL-8 mRNA expression and stimulated IL-8 release in a concentration-dependent manner, whereas the NO-releasing compounds, S-nitroso-N-acetyl-DL-penicillamine and sodium nitroprusside failed to induce cytokine production. Combination of the NO-generating chemicals with a superoxide-generating system (xanthine/xanthine oxidase) markedly increased IL-8 release. Enhanced ONOO- formation was detected in granulocytes, monocytes, lymphocytes, and plasma after challenge with LPS. Furthermore, pyrrolidine dithiocarbamate, an inhibitor of activation of nuclear factor-gammaB, markedly attenuated the induction of IL-8 mRNA expression and IL-8 release by either LPS or ONOO-. Our study identifies ONOO- as a novel signaling mechanism for IL-8 gene expression and suggests that inhibition of ONOO- formation or scavenging ONOO- may represent a novel therapeutic approach to inhibit IL-8 production that could lead to reduction of neutrophil accumulation and activation.

Topics: Adult; Female; Gene Expression Regulation; Guanidines; Humans; Hydroxyl Radical; Interleukin-8; Lipopolysaccharides; Male; Middle Aged; NG-Nitroarginine Methyl Ester; Nitrates; Nitric Oxide; Pyrrolidines; RNA, Messenger; Thiocarbamates

We presently investigated the induction of manganese superoxide dismutase (MnSOD) and nitric oxide synthase (iNOS) mRNA by interleukin-1 beta (IL-1 beta) in insulin-producing RINm5F cells. IL-1 beta induced both mRNAs in parallel, with increased levels detectable after 4 h and further increase at 6 h. Aminoguanidine, a blocker of NO production, did not prevent IL-1 beta-induced MnSOD mRNA expression, and SNP, a NO releasing agent, did not induce MnSOD mRNA. Actinomycin D, an inhibitor of gene transcription, prevented IL-1 beta induction of both MnSOD and iNOS mRNA. Cycloheximide, an inhibitor of protein synthesis, prevented IL-1 beta-induced expression of iNOS mRNA, but not MnSOD mRNA. These data suggest that induction of MnSOD mRNA by IL-1 beta is independent of iNOS expression and NO production. Moreover, while expression of iNOS mRNA depends on protein synthesis, MnSOD mRNA induction does not necessarily require this step. Thus, it seems that IL-1 induces genes potentially involved in cell damage (iNOS) and defense (MnSOD) by different mechanisms.

Topics: Amino Acid Oxidoreductases; Animals; Cell Line; Cycloheximide; Dactinomycin; Enzyme Induction; Gene Expression; Glyceraldehyde-3-Phosphate Dehydrogenases; Guanidines; Humans; Insulin; Interleukin-8; Kinetics; Nitric Oxide Synthase; Recombinant Proteins; RNA, Messenger; Superoxide Dismutase; Time Factors