interleukin-8 and cyclopentenone

Proinflammatory prostaglandins and cytokines are involved in the initiation of human labor and delivery. Although cyclopentenone prostaglandins regulate the formation of these prolabor mediators via nuclear factor-kappaB (NF-kappaB) and/or peroxisome proliferator-activated receptor-gamma, recent evidence suggests that they do not exist in vivo. Cyclopentenone isoprostanes (IsoPs), which are highly reactive structural isomers of bioactive cyclopentenone prostaglandins, do exist physiologically and have been shown to inhibit the inflammatory response in macrophages. Therefore the aim of this study was to determine the effect of the synthetic cyclopentenone IosP 15-A(2)-IsoP on the expression of prolabor mediators in human gestational tissues. Human placenta and gestational membranes (n=5) were incubated in the absence or presence of 12.5, 25, and 50 microM 15-A(2)-IsoP with 10 microg/ml lipopolysaccharide (LPS). Treatment of placenta and fetal membranes with 15-A(2)-IsoP caused a dose-dependent decrease in LPS-stimulated release of the cytokines IL-1beta, IL-6, IL-8, and TNF-alpha and the prostaglandins PGE(2) and PGF(2)alpha. NF-kappaB p65 DNA binding activity was significantly inhibited by treatment with 50 microM 15-A(2)-IsoP. Collectively, these data suggest that 15-A(2)-IsoP exhibits antiinflammatory properties via antagonism of NF-kappaB activity. Cyclopentenone IsoPs may serve as negative feedback regulators of the inflammatory response in human gestational tissues.

Topics: Anti-Inflammatory Agents; Cells, Cultured; Cyclopentanes; Cytokines; Extraembryonic Membranes; Female; Humans; Interleukin-1beta; Interleukin-6; Interleukin-8; Lipopolysaccharides; NF-kappa B; Placenta; Pregnancy; Prostaglandins; Prostaglandins A; Transcription, Genetic; Tumor Necrosis Factor-alpha

Monocyte recruitment to the vessel wall, mediated by monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8), plays an important role in atherogenesis. We have shown previously that minimally oxidized low density lipoprotein, oxidized 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphorylcholine (Ox-PAPC), activates endothelial cells to produce MCP-1 and IL-8. By using liquid chromatography/mass spectrometry methods coupled with bioassay, we report a family of epoxyisoprostane (PEIPC) and epoxycyclopentenone (PECPC) phospholipids that are the components of Ox-PAPC responsible for the majority of this activity. Ox-PAPC contains five chromatographically distinguishable active PEIPC components (m/z 825.5) and four PECPC components (m/z 810.5). All nine components induced endothelial cell synthesis of IL-8 and MCP-1 in a dose-dependent fashion between 0.1 and 5 microm concentrations. The five PEIPC components had identical functional groups and all underwent dehydration to produce m/z 810.5. We present evidence that these phospholipids are regioisomers with epoxide groups at the 5,6-, 8,9-, 11,12-, or 14,15-positions of the sn-2 fatty acid and their epoxide groups is important for biological activity. We have shown previously that peroxisome proliferator-activated receptor alpha is involved in MCP-1 synthesis in response to Ox-PAPC. We now show that PEIPC and PECPC isomers are potent activators of peroxisome proliferator-activated receptor alpha. PEIPC and PECPC isomers are strongly recognized by specific circulating murine natural autoantibodies (EO6) and accumulate in cells treated with IL-1beta. These studies demonstrate that PEIPC and PECPC isomers are potent activators of endothelial cells increasing synthesis of IL-8 and MCP-1. Their accumulation in cells exposed to cytokines and in atherosclerotic lesions suggests that these lipids may play a role in a number of chronic disease processes.

Topics: Binding, Competitive; Cell Line; Chemokine CCL2; Cyclopentanes; Dose-Response Relationship, Drug; Endothelium, Vascular; Enzyme Activation; Gas Chromatography-Mass Spectrometry; Gene Expression Regulation; HeLa Cells; Humans; Hydrolysis; Interleukin-1; Interleukin-8; Isoprostanes; Lipid Metabolism; Luminescent Measurements; Mass Spectrometry; Models, Chemical; Oxygen; Phospholipids; Receptors, Cytoplasmic and Nuclear; Transcription Factors