interleukin-8 and bepafant

Preliminary studies indicate the involvement of interleukin (IL)-12 in experimental renal pathology. In the present study, we evaluated whether cultured glomerular mesangial cells are able to produce IL-12 and whether IL-12 may regulate some of their functions, including the cytoskeletal reorganization, the change in cell shape, and the production of platelet-activating factor (PAF). The results obtained indicate that pro-inflammatory stimuli, such as tumor necrosis factor-alpha and bacterial polysaccharides, induce the expression of IL-12 mRNA and the synthesis of the protein by cultured mesangial cells. Moreover, cultured mesangial cells were shown to bind IL-12 and to express the human low-affinity IL-12 beta1-chain receptor. When challenged with IL-12, mesangial cells produced PAF in a dose- and time-dependent manner and superoxide anions. No production of tumor necrosis factor-alpha and IL-8 was observed. Moreover, we demonstrate that IL-12 induced a delayed and sustained shape change of mesangial cells that reached its maximum between 90 and 120 minutes of incubation. The changes in cell shape occurred concomitantly with cytoskeletal rearrangements and may be consistent with cell contraction. As IL-12-dependent shape change of mesangial cells was concomitant with the synthesis of PAF, which is known to promote mesangial cell contraction, we investigated the role of PAF using two chemically different PAF receptor antagonists. Both antagonists inhibited almost completely the cell shape change induced by IL-12, whereas they were ineffective on angiotensin-II-induced cell shape change. In conclusion, our results suggest that mesangial cells can either produce IL-12 or be stimulated by this cytokine to synthesize PAF and to undergo shape changes compatible with cell contraction.

Topics: Angiotensin II; Azepines; Cell Size; Cells, Cultured; Cytoskeleton; Dose-Response Relationship, Drug; Glomerular Mesangium; Humans; Interleukin-12; Interleukin-8; Lipopolysaccharides; Platelet Activating Factor; Platelet Aggregation Inhibitors; Receptors, Interleukin; Receptors, Interleukin-12; RNA, Messenger; Superoxides; Time Factors; Triazoles; Tumor Necrosis Factor-alpha

In this study, we demonstrate that human umbilical cord vein-derived endothelial cells (HUVECs) expressed c-Mpl, the thrombopoietin (TPO) receptor, and that TPO activates HUVECs in vitro, as indicated by directional migration, synthesis of 1-alkyl-/1-acyl-platelet-activating factor (PAF) and interleukin-8 (IL-8), and phosphorylation of the signal transducers and activators of transcription (STAT) STAT1 and STAT5B. The observation that WEB 2170 and CV3988, 2 structurally unrelated PAF receptor antagonists, prevented the motility of HUVECs induced by TPO suggests a role of PAF as secondary mediator. Moreover, kinetic analysis of TPO-induced tyrosine phosphorylation of STAT demonstrated that STAT5B activation temporally correlated with the synthesis of PAF. PAF, in turn, induced a rapid tyrosine phosphorylation of STAT5B and PAF receptor blockade, by WEB 2170, preventing both TPO- and PAF-mediated STAT5B activation. The in vivo angiogenic effect of TPO, studied in a mouse model of Matrigel implantation, demonstrated that TPO induced a dose-dependent angiogenic response that required the presence of heparin. Moreover, the in vivo angiogenic effect of TPO was inhibited by the PAF receptor antagonist WEB 2170 but not by the anti-basic fibroblast growth factor neutralizing antibody. These results indicate that the effects of TPO are not restricted to cells of hematopoietic lineages, because TPO is able to activate endothelial cells and to induce an angiogenic response in which the recruitment of endothelial cells is mediated by the synthesis of PAF. Moreover, biochemical analysis supports the hypothesis that STAT5B may be involved in the signaling pathway leading to PAF-dependent angiogenesis.

Topics: Animals; Azepines; Biocompatible Materials; Biological Transport; Cell Division; Cell Movement; Cell Nucleus; Cells, Cultured; Collagen; DNA-Binding Proteins; Drug Combinations; Endothelium, Vascular; Fibroblast Growth Factor 2; Gene Expression; Humans; Interleukin-8; Kinetics; Laminin; Mice; Milk Proteins; Neoplasm Proteins; Neovascularization, Physiologic; Phosphorylation; Platelet Activating Factor; Platelet Aggregation Inhibitors; Proteoglycans; Proto-Oncogene Proteins; Receptors, Cytokine; Receptors, Thrombopoietin; Signal Transduction; STAT1 Transcription Factor; STAT5 Transcription Factor; Thrombopoietin; Trans-Activators; Triazoles; Tyrosine; Umbilical Veins

Compounds generated during the routine storage of platelet concentrates may have deleterious effects on the transfusion recipient.. Daily plasma samples from platelet concentrates, both apheresis platelets and those separated from whole blood, were obtained serially during routine storage. These plasma samples were assayed for their ability to prime the NADPH oxidase in isolated human neutrophils. Quantitative and qualitative analysis of the priming agents was completed by lipid extraction, high-pressure liquid chromatography separation, and gas chromatography/mass spectroscopy.. Compounds were generated in both apheresis and whole-blood platelets that significantly primed the NADPH oxidase after 24 and 48 hours of storage, respectively. The priming activity was maximal by component outdate: 2.6-fold that of the buffer-treated control neutrophils (apheresis) and 3.9-fold that of the buffer-treated control neutrophils (whole blood). These agents were generated by cellular constituents, as stored plasma did not demonstrate such priming activity. Inhibition of this priming activity by WEB 2170, a specific platelet-activating factor receptor antagonist, suggested that the observed priming involved the platelet-activating factor receptor. A portion of the priming activity from platelet concentrates was organically extractable: 69 percent of that from apheresis platelets and 46 percent of that from whole-blood platelets. Further purification of the lipid's priming activity by normal-phase high-pressure liquid chromatography demonstrated a single peak of priming activity at the retention time of lysophosphatidylcholines. Because 46 percent of the priming activity from whole-blood platelets was chloroform insoluble and because it has been reported that interleukin 8 is generated during routine storage of whole-blood platelets, the effects of interleukin 8 on the NADPH oxidase were examined. Recombinant monocyte interleukin 8 rapidly primed the oxidase but was not inhibited by WEB 2170.. Lipids were generated during the routine storage of platelet concentrates that prime the NADPH oxidase, and they may play a role in the severe complications of transfusion therapy. Other non-lipid compounds, such as interleukin 8, that are generated in whole-blood platelets may also contribute to the observed priming activity of plasma.

Topics: Adult; Azepines; Blood Platelets; Blood Preservation; Humans; Interleukin-8; Lipids; NADH, NADPH Oxidoreductases; NADPH Oxidases; Platelet Transfusion; Triazoles