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Ji Ming Wang - One of the best experts on this subject based on the ideXlab platform.
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bacterial lipopolysaccharide selectively up regulates the function of the Chemotactic Peptide receptor formyl Peptide receptor 2 in murine microglial cells
Journal of Immunology, 2002Co-Authors: Youhong Cui, Wang Hua Gong, Paul Proost, Jozef Van Damme, William J Murphy, Ji Ming WangAbstract:Receptors for the bacterial Chemotactic Peptide fMLP are implicated in inflammation and host defense against microbial infection. We investigated the expression and function of fMLPR in microglial cells, which share characteristics of mononuclear phagocytes and play an important role in proinflammatory responses in the CNS. The expression of the genes encoding formyl Peptide receptor (FPR)1 and FPR2, the high- and low-affinity fMLPR, was detected in a murine microglial cell line N9, but these cells did not respond to Chemotactic agonists known for these receptors. N9 cells incubated with bacterial LPS increased the expression of fMLPR genes and developed a species of specific, but low-affinity, binding sites for fMLP, in association with marked calcium mobilization and chemotaxis responses to fMLP in a concentration range that typically activated the low-affinity receptor FPR2. In addition, LPS-treated N9 cells were chemoattracted by two FPR2-specific agonists, the HIV-1 envelope-derived V3 Peptide, and the 42 aa form of the amyloid beta Peptide which is a pathogenic agent in Alzheimer's disease. Primary murine microglial cells also expressed FPR1 and FPR2 genes, but similar to N9 cells, exhibited FPR2-mediated activation only after LPS treatment. In contrast to its effect on the function of FPR2, LPS reduced N9 cell binding and biological responses to the chemokine stromal cell-derived factor-1alpha. Thus, LPS selectively modulates the function of chemoattractant receptors in microglia and may promote host response in inflammatory diseases in the CNS.
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bacterial lipopolysaccharide selectively up regulates the function of the Chemotactic Peptide receptor formyl Peptide receptor 2 in murine microglial cells
Journal of Immunology, 2002Co-Authors: Youhong Cui, Wang Hua Gong, Paul Proost, Jozef Van Damme, William J Murphy, Ji Ming WangAbstract:Receptors for the bacterial Chemotactic Peptide fMLP are implicated in inflammation and host defense against microbial infection. We investigated the expression and function of fMLPR in microglial cells, which share characteristics of mononuclear phagocytes and play an important role in proinflammatory responses in the CNS. The expression of the genes encoding formyl Peptide receptor (FPR)1 and FPR2, the high- and low-affinity fMLPR, was detected in a murine microglial cell line N9, but these cells did not respond to Chemotactic agonists known for these receptors. N9 cells incubated with bacterial LPS increased the expression of fMLPR genes and developed a species of specific, but low-affinity, binding sites for fMLP, in association with marked calcium mobilization and chemotaxis responses to fMLP in a concentration range that typically activated the low-affinity receptor FPR2. In addition, LPS-treated N9 cells were chemoattracted by two FPR2-specific agonists, the HIV-1 envelope-derived V3 Peptide, and the 42 aa form of the amyloid β Peptide which is a pathogenic agent in Alzheimer’s disease. Primary murine microglial cells also expressed FPR1 and FPR2 genes, but similar to N9 cells, exhibited FPR2-mediated activation only after LPS treatment. In contrast to its effect on the function of FPR2, LPS reduced N9 cell binding and biological responses to the chemokine stromal cell-derived factor-1α. Thus, LPS selectively modulates the function of chemoattractant receptors in microglia and may promote host response in inflammatory diseases in the CNS.
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novel pathophysiological role of classical Chemotactic Peptide receptors and their communications with chemokine receptors
Immunological Reviews, 2000Co-Authors: Wang Hua Gong, Nancy M Dunlop, Joost J Oppenheim, Weiping Shen, Ji Ming WangAbstract:The bacterial N-formylPeptides, such as N-formyl-Met-Leu-Phe (fMLF), are some of the first identified and most potent chemoattractants for phagocytic leukocytes. Two fMLF receptors, the high affinity formyl Peptide receptor (FPR) and its low affinity variant FPR-like 1 (FPRL1), belong to the seven-transmembrane, Gi protein-coupled receptor superfamily which also includes chemokine receptors. Despite their reaction with bacterial Chemotactic Peptides, the physiological role of these receptors in humans remains unclear. Our recent studies have identified novel exogenous as well as host-derived agonists for FPR and FPRL1. Furthermore, activation of these receptors by their agonists results in desensitization of the receptors for other chemoattractants, including two chemokine receptors, CCR5 and CXCR4, which serve as major co-receptors for HIV-1. These results suggest that FPR and FPRL1 may play important roles not only in host defense and immunological responses but also in the fine tuning of cell activation in the presence of multiple stimuli.
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t21 dp107 a synthetic leucine zipper like domain of the hiv 1 envelope gp41 attracts and activates human phagocytes by using g protein coupled formyl Peptide receptors
Journal of Immunology, 1999Co-Authors: Shao Bo Su, Wang Hua Gong, Nancy M Dunlop, Philip M Murphy, Joost J Oppenheim, Ji Ming WangAbstract:A leucine zipper-like domain, T21/DP107, located in the amino terminus of the ectodomain of gp41, is crucial to the formation of fusogenic configuration of the HIV-1 envelope protein gp41. We report that the synthetic T21/DP107 segment is a potent stimulant of migration and calcium mobilization in human monocytes and neutrophils. The activity of T21/DP107 on phagocytes was pertussis toxin-sensitive, suggesting this Peptide uses Gi-coupled seven-transmembrane receptor(s). Since the bacterial Chemotactic Peptide fMLP partially desensitized the calcium-mobilizing activity of T21/DP107 in phagocytes, we postulated that T21/DP107 might preferentially use a lower affinity fMLP receptor. By using cells transfected to express cloned prototype Chemotactic N -formyl Peptide receptor (FPR) or its variant, FPR-like 1 (FPRL1), we demonstrate that T21/DP107 activates both receptors but has a much higher efficacy for FPRL1. In addition, T21/DP107 at nM concentrations induced migration of FPRL1-transfected human embryonic kidney 293 cells. In contrast, fMLP did not induce significant chemotaxis of the same cells at a concentration as high as 50 μM. Although a lipid metabolite, lipoxin A4, was a high-affinity ligand for FPRL1, it was not reported to induce Ca 2+ mobilization or chemotaxis in FPRL1-transfected cells. Therefore, T21/DP107 is a first Chemotactic Peptide agonist identified thus far for FPRL1. Our results suggest that this Peptide domain of the HIV-1 gp41 may have the potential to activate host innate immune response by interacting with FPR and FPRL1 on phagocytes.
Verena Niggli - One of the best experts on this subject based on the ideXlab platform.
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microtubule disruption induced and Chemotactic Peptide induced migration of human neutrophils implications for differential sets of signalling pathways
Journal of Cell Science, 2003Co-Authors: Verena NiggliAbstract:Neutrophil granulocytes rely on a functional actin network for directed migration. Microtubule disassembly does not impair receptor-linked chemotaxis, instead it induces development of polarity and chemokinesis in neutrophils concomitant with polarized distribution of alpha-actinin and F-actin. Cells stimulated with colchicine, which disassembles microtubules, migrate with a speed comparable to cells exposed to Chemotactic Peptide. We investigated signalling pathways involved in colchicine-induced neutrophil polarization and migration. Colchicine-induced development of polarity was insensitive to treatment with pertussis toxin, in contrast to Chemotactic-Peptide-induced shape changes, which were completely abolished by this treatment. Thus, colchicine does not appear to act via activating heterotrimeric G(i) proteins. Colchicine does also not seem to act via phosphatidylinositol 3-kinase, as it failed to induce phosphorylation of its downstream target Akt and the potent phosphatidylinositol 3-kinase inhibitor wortmannin failed to inhibit colchicine-induced shape changes. By contrast, wortmannin significantly reduced Chemotactic-Peptide-induced shape changes. However, the Rho-kinase inhibitor Y-27632 (10 micro M) inhibited colchicine-induced development of polarity by 95+/-3% (n=5) and chemokinesis by 76+/-9% (n=3), which suggests that the Rho-Rho-kinase pathway has a crucial role in polarity and migration. Indeed, treatment of cells with colchicine induced a significant increase in membrane-bound Rho-kinase II, which is indicative of activation of this protein. This membrane translocation could be prevented by taxol, which stabilizes microtubules. Colchicine also induced a marked increase in myosin light chain phosphorylation, which could be suppressed by Y-27632 and by taxol. In summary, we provide evidence that microtubule disassembly induces in neutrophils a selective activation of Rho-kinase, bypassing activation of heterotrimeric Gi proteins and phosphatidylinositol 3-kinase. This process is sufficient for induction of chemokinesis and mediates increased phosphorylation of myosin light chain and accumulation of F-actin and alpha-actinin in the leading edge.
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differentiated hl 60 cells are a valid model system for the analysis of human neutrophil migration and chemotaxis
The International Journal of Biochemistry & Cell Biology, 2002Co-Authors: Anna Barbara Hauert, Sibylla Martinelli, Camilla Marone, Verena NiggliAbstract:Abstract We have carried out a detailed comparison of the motile properties of differentiated HL-60 cells and human peripheral blood neutrophils. We compared the effects of Chemotactic stimuli and of inhibitors of signalling proteins on morphology, chemokinesis and chemotaxis of neutrophils and differentiated HL-60 cells using videomicroscopy and a filter assay for chemotaxis. We also assessed expression of signalling and cytoskeletal proteins using Western blotting. Chemotactic Peptide induced a front-tail polarity in HL-60 cells comparable to that of neutrophils. Chemokinetic and Chemotactic responses to Chemotactic Peptide were also very similar for both cell types, concerning mean speed of migration, the fraction of migrated cells and the concentration of stimulus optimal for activation. The cytokine interleukin-8 was in contrast clearly less effective in activating motile responses of differentiated HL-60 cells as compared to neutrophils. An important functional role of Rho-activated kinases and phosphatidylinositol 3-kinase in motile responses of HL-60 cells, consistent with their upregulation during differentiation, could be confirmed using inhibitors with specificity for the corresponding enzymes. The only difference observed here between HL-60 cells and neutrophils concerned the differential effects of a protein kinase C inhibitor. In summary, the results presented here show that differentiated HL-60 cells, stimulated with Chemotactic Peptide, are a valid model system to study molecular mechanisms of neutrophil emigration.
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rho kinase in human neutrophils a role in signalling for myosin light chain phosphorylation and cell migration
FEBS Letters, 1999Co-Authors: Verena NiggliAbstract:The role of a Rho-associated coiled-coil forming kinase in migration of neutrophils has been investigated. Rho-associated coiled-coil forming kinase I was expressed in human neutrophils. Chemotactic Peptide led to a Rho-associated coiled-coil forming kinase-dependent increase in phosphorylation of myosin light chain. This was determined with the help of an antibody directed against serine 19-phosphorylated myosin light chain and an inhibitor of Rho-associated coiled-coil forming kinase (Y-27632). Y-27632 suppressed myosin light chain phosphorylation and Chemotactic Peptide-induced development of cell polarity and locomotion with similar potency (ED50 0.5–1.1 μM). The data strongly suggest that a Rho-associated coiled-coil forming kinase isoform, activated in human neutrophils exposed to Chemotactic Peptide, is important for motile functions of these cells.
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rho kinase in human neutrophils a role in signalling for myosin light chain phosphorylation and cell migration
FEBS Letters, 1999Co-Authors: Verena NiggliAbstract:The role of a Rho-associated coiled-coil forming kinase in migration of neutrophils has been investigated. Rho-associated coiled-coil forming kinase I was expressed in human neutrophils. Chemotactic Peptide led to a Rho-associated coiled-coil forming kinase-dependent increase in phosphorylation of myosin light chain. This was determined with the help of an antibody directed against serine 19-phosphorylated myosin light chain and an inhibitor of Rho-associated coiled-coil forming kinase (Y-27632). Y-27632 suppressed myosin light chain phosphorylation and Chemotactic Peptide-induced development of cell polarity and locomotion with similar potency (ED50 0.5–1.1 μM). The data strongly suggest that a Rho-associated coiled-coil forming kinase isoform, activated in human neutrophils exposed to Chemotactic Peptide, is important for motile functions of these cells.
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the phosphatidylinositol 3 kinase inhibitor wortmannin markedly reduces Chemotactic Peptide induced locomotion and increases in cytoskeletal actin in human neutrophils
European Journal of Pharmacology, 1997Co-Authors: Verena Niggli, H U KellerAbstract:Abstract To define a possible role of the enzyme phosphatidylinositol 3-kinase (PI 3-kinase) in motile functions of neutrophils, we have used a potent inhibitor of this enzyme, [1S-(1α,6bα,9aβ,11α,11bβ)]-11-(acetyloxy)-1,6b,7,8,9a,10,11,11b-octahydro-1-(methoxymethyl)-9a,11b-dimethyl-3H-furo[4,3,2-de]indeno[4,5-h]-2-benzopyran-3,6,9-trione (wortmannin). Wortmannin markedly attenuated Chemotactic Peptide-induced development of polarity, locomotion and increases in cytoskeletal actin and α-actinin in human neutrophils at low, nM, concentrations (ED50=4–40 nM; 0.4–3 pmol/106 cells). The increase in cytoskeletal actin induced by phorbol-12-myristate-13-acetate in contrast was not affected by wortmannin (18 pmol/106 cells). Moreover, the increase in total F-actin induced by an incubation for 1 min with Chemotactic Peptide was much less sensitive to wortmannin than increases in cytoskeletal actin; 80 pmol/106 cells were necessary for half-maximal inhibition. Wortmannin thus appears to primarily affect F-actin organization, rather than polymerization. Inhibition of development of polarity by wortmannin correlated with inhibition of production of phosphatidylinositol 3,4,5-trisphosphate. According to our findings, activation of a wortmannin-sensitive target, very likely PI 3-kinase, is required for optimal Chemotactic Peptide-induced neutrophil motility.
Robert M Strieter - One of the best experts on this subject based on the ideXlab platform.
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production of il 8 and monocyte Chemotactic Peptide 1 by peripheral blood monocytes disparate responses to phytohemagglutinin and lipopolysaccharide
Journal of Immunology, 1994Co-Authors: Janice M Liebler, Mark W Rolfe, Theodore J Standiford, Marie D Burdick, S L Kunkel, Robert M StrieterAbstract:The temporal recruitment of leukocytes to a site of inflammation is dependent on a complex interplay of a number of soluble mediators. Recently, two families of Chemotactic cytokines have been discovered. The -C-X-C-family, which includes IL-8, appears to recruit neutrophils and lymphocytes. In contrast, the -C-C-family, which includes monocyte Chemotactic Peptide-1 (MCP-1), appears to recruit predominantly monocytes. Monocytes, after their arrival at a site of inflammation, could further amplify the immune response by secreting IL-8 and MCP-1. We sought to define conditions under which human peripheral blood monocytes produce IL-8 and MCP-1. Using serum-free media, we found that PHA-stimulated monocytes expressed MCP-1 and IL-8 protein and mRNA in a dose-dependent manner. However, the onset of mRNA expression for MCP-1 occurred at least 3 h later than did the onset of IL-8 mRNA expression. IL-8 and MCP-1 gene expression by monocytes appeared to require de novo protein synthesis, in that cycloheximide blocked the expression of mRNA for both IL-8 and MCP-1 in PHA-stimulated cells. However, treatment of monocytes with cycloheximide resulted in the superinduction of IL-8 compared with control monocytes. Monocytes costimulated with PHA and LPS demonstrated enhanced amounts of IL-8 mRNA and protein, but sharply decreased amounts of MCP-1 mRNA and protein. The addition of serum to culture media increased both the constitutive and PHA-induced production of monocyte-derived MCP-1 and IL-8, but had no effect on the inhibition of PHA-stimulated MCP-1 production by LPS. These findings suggest that distinct pathways of activation exist for the production of monocyte-derived IL-8 and MCP-1. The differential expression of these different but related polyPeptides may offer a means of control of the type of immune cells that are recruited to a site of inflammation.
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recruitment of inflammatory cells to the pleural space Chemotactic cytokines il 8 and monocyte Chemotactic Peptide 1 in human pleural fluids
Journal of Immunology, 1993Co-Authors: Veena B Antony, Steven L Kunkel, Marie D Burdick, Steven W Godbey, Jeffery W Hott, Daniel L Hartman, Robert M StrieterAbstract:Pleural effusions secondary to various diseases are associated with the presence of different inflammatory cells. The role of selective Chemotactic cytokines in the recruitment of phagocytes to the pleural space is unclear. IL-8 and monocyte Chemotactic Peptide-1 (MCP-1) are recently described cytokines that are Chemotactic for neutrophils and monocytes, respectively. We prospectively studied 63 patients, using strictly defined criteria for their selection. IL-8 concentrations were elevated in both empyema fluid (9.15 +/- 0.89 ng/ml) and parapneumonic effusions (4.7 +/- 0.697 ng/ml) when compared with pleural effusions secondary to other diseases. IL-8 levels were higher in empyema fluid than in parapneumonic effusions (p = 0.01). There was a significant correlation between IL-8 levels and the total numbers of neutrophils in empyema fluids (r = 0.80). Chemotactic activity for neutrophils was elevated in empyema fluid and the addition of IL-8 neutralizing serum decreased bioactivity by 32.22%. Malignant pleural effusions had the highest levels of MCP-1 (12.0 +/- 3.7 ng/ml) when compared with others. Cytology-positive pleural fluids (n = 10) had a higher level of MCP-1 than cytology-negative effusions (p = < 0.05). Malignant pleural fluid MCP-1 levels correlated (r = 0.70) with the absolute number of monocytes in the pleural fluid. Neutralization of monocyte Chemotactic activity of malignant pleural fluid by specific neutralizing serum caused a 70.3% inhibition of bioactivity. Immunohistochemical staining of malignant pleural fluid localized antigenic MCP-1 to malignant cells. We conclude that both IL-8 and MCP-1 play major but not exclusive roles in the recruitment of neutrophils and monocytes from the vascular compartment to the pleural space.
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interferon γ regulation of human renal cortical epithelial cell derived monocyte Chemotactic Peptide 1
Kidney International, 1993Co-Authors: Robert L Schmouder, Robert M Strieter, Steven L KunkelAbstract:Interferon-γ regulation of human renal cortical epithelial cell-derived monocyte Chemotactic Peptide-1. The chemoattractant signal(s) that results in the transmigration of monocytes/macrophage into the tubulointerstitium during acute inflammation is not known. Monocyte Chemotactic Peptide-1 (MCP-1), a recently described Chemotactic cytokine, may function as both a potent monocyte chemotaxin and activator in renal inflammation. We have studied the proinflammatory conditions in which cultured human renal cortical epithelial cells (RCEC) of tubular origin may be stimulated to produce MCP-1. RCEC were stimulated in a dose-time dependent manner with: IL-1β (0.01 to 1.0 ng/ml), TNF (0.1 to 10 ng/ml), LPS (0.1 to 10 µg/ml) or INF-γ (10–1000 U/ml). Conditioned media from RCEC stimulated with either IL-1β3 or INF-γ produced a monocyte chemoattractant activity which was significantly suppressed with neutralizing antibody to MCP-1. Stimulation of RCEC with either IL-1β or INF-γ resulted in a significant (4- to 5-fold) increase in steady state levels of MCP-1 mRNA. MCP-1 antigenic Peptide in RCEC conditioned media was significantly increased over control (2- to 2.5-fold) after stimulation with either IL-1β or INF-γ. In contrast, production of interleukin-8 (IL-8), a neutrophil Chemotactic cytokine, was not stimulated by INF-γ in RCEC. Thus, the chemokine signaling repertoire of renal tubule cells may be selectively controlled by INF-γ.
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expression and regulation of human pulmonary fibroblast derived monocyte Chemotactic Peptide 1
American Journal of Physiology-lung Cellular and Molecular Physiology, 1992Co-Authors: Mark W Rolfe, Steven L Kunkel, Theodore J Standiford, Mark B Orringer, Sem H Phan, Holly L Evanoff, Marie D Burdick, Robert M StrieterAbstract:Monocyte recruitment is essential for maintenance of normal pulmonary macrophage populations. In addition, acute and chronic inflammatory pulmonary diseases are associated with sequestration of mononuclear phagocytes in the lung. Although alveolar macrophages (AM phi) can secrete a number of potent inflammatory and chemoattractment mediators, these immune cells do not produce monocyte Chemotactic Peptide (MCP-1) in response to lipopolysaccharide (LPS), tumor necrosis factor (TNF), or interleukin-1 beta (IL-1 beta). The pulmonary fibroblast (PF) may play a pivotal role in monocyte recruitment. In these studies, we demonstrate a time- and dose-dependent production of PF-derived steady-state MCP-1 mRNA, MCP-1 antigen, and monocyte Chemotactic bioactivity attributable to MCP-1. In cellular models examining cytokine networks between AM phi and PF, LSP-stimulated AM phi (conditioned media) induced PF-derived steady-state MCP-1 mRNA expression that was markedly attenuated by the presence of neutralizing TNF and IL-1 beta antibodies. Furthermore, we showed the dose- and time-dependent suppression of IL-1 beta-stimulated PF-derived MCP-1 by dexamethasone and prostaglandin E2. These findings demonstrated that PF are an important cellular source of MCP-1 and this production of MCP-1 may be influenced by immunomodulators.
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il 1 receptor antagonist inhibits monocyte Chemotactic Peptide 1 generation by human mesangial cells
Kidney International, 1992Co-Authors: Zarin Brown, Robert M Strieter, Steven L Kunkel, Guy H Neild, Robert C Thompson, John WestwickAbstract:IL-1 receptor antagonist inhibits monocyte Chemotactic Peptide 1 generation by human mesangial cells. The elicitation of neutrophils and monocytes from the circulation into the inflamed glomerulus is a key process in the pathogenesis of proliferative glomerulonephritis. The aim of this study was to determine the factors which regulate the expression and synthesis of the monocyte specific chemotaxin, monocyte Chemotactic Peptide 1 (MCP-1). Mesangial cells in culture did not constitutively express MCP-1, but could be induced to express both MCP-1 mRNA and antigenic MCP-1 by either stimulation with IL-1α or TNFα, which are also stimuli for interleukin 8 (IL-8/NAP-1) expression and release. Pre-treatment of mesangial cells with the IL-1 receptor antagonist (IL-1ra) induced dose-dependent inhibition of both the expression of MCP-1 and IL-8 mRNA as well as the release of both Chemotactic Peptides in response to IL-1α, while the receptor antagonist had no significant effect on TNFα induced MCP-1 and IL-8 generation. This study demonstrates that the IL-1 receptor antagonist was four times more effective at inhibiting the IL-1 induced expression and release of IL-8 compared to that of MCP-1. These results suggest that mesangial cell-derived MCP-1 may play an important role in the recruitment of monocytes in glomerular inflammation and that an IL-1 receptor antagonist may have therapeutic potential for the treatment of glomerulonephritis.
Alan J Fischman - One of the best experts on this subject based on the ideXlab platform.
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Chemotactic Peptide uptake in acute pancreatitis correlation with tissue accumulation of leukocytes
Journal of Applied Physiology, 1999Co-Authors: Werner Hartwig, Alan J Fischman, Edward A Carter, Ramon E Jimenez, Jens Werner, Carlos Fernandezdel Castillo, Andrew L WarshawAbstract:Chemotactic Peptides bind specifically to receptors on leukocyte membranes. This property makes them prospective vehicles to evaluate inflammation and infection. We used two well-established models of acute pancreatitis to quantitate the binding of the Chemotactic Peptide N -formyl-methionyl-leucyl-phenylalanine-lysine (fMLFK) to leukocytes and its correlation to degree of organ inflammation. Uptake of the99mTc-labeled nicotinyl hydrazine-derivatized Chemotactic Peptide analog fMLFK-HYNIC was measured in blood, pancreas, lung, and muscle specimens in rats with edematous or necrotizing pancreatitis and was compared with neutrophil sequestration assessed by myeloperoxidase activity and histology. Chemotactic Peptide uptake in the pancreas was increased in mild and severe pancreatitis compared with controls, with higher levels in severe than in mild disease, and correlated with tissue myeloperoxidase activity ( r = 0.7395, P < 0.001). Increased pulmonary uptake only in severe pancreatitis reflected pancreatitis-induced neutrophil sequestration in the lungs. Muscle uptake was unchanged compared with controls. Edema formation did not affect Chemotactic Peptide uptake. The data suggest that uptake of Chemotactic Peptides can contribute to quantitative assessment of neutrophils in localized inflammatory processes and is independent of associated edema formation or microcirculatory compromise.
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localization of radiolabeled Chemotactic Peptide at focal sites of escherichia coli infection in rabbits evidence for a receptor specific mechanism
The Journal of Nuclear Medicine, 1997Co-Authors: John W Babich, Ronald G Tompkins, Wendy Graham, Sandra A Barrow, Alan J FischmanAbstract:The infection imaging properties of a high-affinity ""Tc-labeled Chemotactic Peptide receptor agonist (N-formyl-methionyl-leucylphenylalanine-lysine; N-For-MLFK) were compared with a lowaffinity agonist (N-Acetyl-MLFK; N-Ac-MLFK), a moderate-affinity antagonist (N-isobutyloxycarbonyl-MLFK; N-iBoc-MLFK) and non specific inflammation imaging agents. Methods: All Peptides were prepared by solid-phase methods and purified by high-perfor mance liquid chromatography. The products were assayed in vitro for N-formyl-methionyl-leucyl-phenylalanine receptor binding and Superoxide production. Three types of studies were performed in rabbits with Escherichia coli infection: (Study A) Four groups of six animals were coinjected with "Tc-N-For-MLFK-hydrazinonicotinamide (N-For-MLFK-HYNIC) plus 111ln-immunoglobulin G, 111 Inred blood cells or1111n-diethylenetriamine pentaacetic acid. (Study B) Three groups of six rabbits were coinjected with 1111n-leukocytes plus 99mTc-N-For-MLFK-HYNIC, ""Tc-N-Ac-MLFK-HYNIC or 99mTc-N-iBoc-MLFK-HYNIC. (Study C) Two groups of six rabbits were injected with 99rtTc-N-For-MLFK-HYNIC and 1111n-leukocytes with and without an excess of antagonist. In all three studies, the radiopharmaceuticals were injected 24 hr after infection and dual photon (""Tc and 1111n) gamma camera images were acquired at 2-3 and 16-18 hr later. Target-to-background (T/B) ratios were calculated for regions of interest drawn over the infected and contralateral normal tissue. Results: N-For-MLFK, N-Ac-MLFK and N-iBoc-MLFK had EC50sfor receptor binding of 2.0, 830 and 150 n/W,respectively. The corresponding EC50sfor Superoxide produc tion were 20.0, = 103and > 104.Study A demonstrated that the T/B for 99mTc-N-For-MLFK-HYNIC was higher than for any of the nonspecific imaging agents (p < 0.001), and 111ln-immunoglobulin G had a higher T/B ratio than 1111n-diethylenetriamine pentaacetic acid (p < 0.01) or I11ln-red blood cells (p = NS). Study B showed that 99nTTc-N-For-MLFK-HYNIChad a higher T/B ratio than the other Peptides (p < 0.001). 111ln-leukocytes and 99rTTc-N-iBocMLFK-HYNIC had comparable T/B ratios, which were higher than for 99mTc-N-Ac-MLFK-HYNIC (p < 0.05). Study C demonstrated that coinjection with an antagonist resulted in a significant reduction in the T/B ratio for 99mTc-N-For-MLFK-HYNIC(p < 0.001), but did not affect the T/B ratio for1111n-leukocytes. Conclusion: Nonspe cific mechanisms contribute minimally to the localization of 99mTcChemotactic Peptide analogs at sites of infection and the majority of the accumulation appears to be receptor mediated. Also, chemo tactic Peptide receptor antagonists can be used for infection imag ing. These results provide important new insights for future radiopharmaceutical development.
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comparison of the infection imaging properties of a 99mtc labeled Chemotactic Peptide with 111in igg
Nuclear Medicine and Biology, 1995Co-Authors: John W Babich, Wendy Graham, Sandra A Barrow, Alan J FischmanAbstract:Abstract The biodistribution and infection imaging properties of a 99mTc labeled hydrazino nicotinamide (HYNIC) derivatized Chemotactic Peptide analog (For-Met-Leu-Phe-Lys-HYNIC) and 111In-DTPA-IgG were compared in rabbits with Escherichia coli infection. Six New Zealand white rabbits were injected in the left posterior thigh with a suspension of E. coli. Twenty four hours later, the animals were injected with: 1.0 mCi of 99mTc labeled Peptide plus 0.1 mCi of 111In-DTPA-IgG. At 2–3 and 16–18 h, dual photon scintigrams were acquired and the images were corrected for crossover between the two windows. After recording the final images, the animals were sacrificed and biodistribution was determined. At both imaging times the biodistributions of the two reagents were markedly different. The highest concentrations of 111In-DTPA-IgG were detected in blood pool structures, liver and kidney. In contrast localization of 99mTc labeled Peptide was greatest in spleen, lung and liver (consistent with binding to leukocytes). In general, the sites of infection were better visualized with the radiolabeled Peptide and T B ratios increased with time (P T B for 99mTc- Peptide were higher (P
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detection of acute bacterial infection within soft tissue injuries using a 99mtc labeled Chemotactic Peptide
Journal of Trauma-injury Infection and Critical Care, 1995Co-Authors: Alan J Fischman, John W Babich, Ronald G Tompkins, Wendy Graham, Sandra A Barrow, Edward A Carter, R H RubinAbstract:Objective Infection imaging with a99m Tc-labeled Chemotactic Peptide was evaluated in a rabbit model of Escherichia coli infections in burned tissue.Materials and Methods The Peptide was radiolabeled with99 sup m Tc via the hydrazino nicotinamide derivative. Three groups of six animals were studied:
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infection imaging with technetium 99m labeled Chemotactic Peptide analogs
Seminars in Nuclear Medicine, 1994Co-Authors: Alan J Fischman, John W Babich, R H RubinAbstract:The localization of occult sites of infection is frequently essential to the therapeutic management of critically ill patients. Current imaging procedures, including computed tomography, ultrasound, magnetic resonance imaging, and conventional radiography, rely primarily on focal changes in tissue density or composition to define the lesion. Typically, these are relatively late changes in the inflammatory process. Radionuclide procedures which have been used to localize early inflammatory processes, require a minimum of 12 hours, and usually 24 to 48 hours, from the time of injection to imaging. Clearly, a method of rapidly localizing sites of acute inflammation would be helpful for patient management. Recently, we developed methods for preparing analogs of the leukocyte chemoat-tractant Peptide, N-formyl-methionyl-leucyl-phenylalanine (ForMLF), that can be radiolabeled for external imaging. In vitro, these compounds have bioactivity and neutrophil ForMLF receptor binding comparable with that of the native Peptide. Studies in animals demonstrate that these agents bind to leucocytes in vivo, clear from the circulation rapidly, and localize at sites of Escherichia coli infection to an extent sufficient to yield external images early after injection. However, even at relatively low doses, the Peptides elicit a profound but transient reduction in peripheral leukocyte levels. Despite this, if the Peptides could be radiolabeled at very high specific activity, imaging might be possible with doses of Peptide that do not reduce peripheral leukocyte levels. Recently, hydrazino nicotinamide-derivatized Peptides were prepared and radiolabeled with technetium-99m at extremely high specific activity (>20,000 mCi/μmole). In a rabbit model of E coli infection, these Peptides yielded excellent images of sites of infection at injected doses that are approximately 1,000-fold below the level that produces a significant reduction in peripheral leukocytes. In addition, studies of thermally injured infected animals indicate that Peptide localization may be infection selective, with very low levels of accumulation at sites of sterile inflammation.
Wang Hua Gong - One of the best experts on this subject based on the ideXlab platform.
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bacterial lipopolysaccharide selectively up regulates the function of the Chemotactic Peptide receptor formyl Peptide receptor 2 in murine microglial cells
Journal of Immunology, 2002Co-Authors: Youhong Cui, Wang Hua Gong, Paul Proost, Jozef Van Damme, William J Murphy, Ji Ming WangAbstract:Receptors for the bacterial Chemotactic Peptide fMLP are implicated in inflammation and host defense against microbial infection. We investigated the expression and function of fMLPR in microglial cells, which share characteristics of mononuclear phagocytes and play an important role in proinflammatory responses in the CNS. The expression of the genes encoding formyl Peptide receptor (FPR)1 and FPR2, the high- and low-affinity fMLPR, was detected in a murine microglial cell line N9, but these cells did not respond to Chemotactic agonists known for these receptors. N9 cells incubated with bacterial LPS increased the expression of fMLPR genes and developed a species of specific, but low-affinity, binding sites for fMLP, in association with marked calcium mobilization and chemotaxis responses to fMLP in a concentration range that typically activated the low-affinity receptor FPR2. In addition, LPS-treated N9 cells were chemoattracted by two FPR2-specific agonists, the HIV-1 envelope-derived V3 Peptide, and the 42 aa form of the amyloid beta Peptide which is a pathogenic agent in Alzheimer's disease. Primary murine microglial cells also expressed FPR1 and FPR2 genes, but similar to N9 cells, exhibited FPR2-mediated activation only after LPS treatment. In contrast to its effect on the function of FPR2, LPS reduced N9 cell binding and biological responses to the chemokine stromal cell-derived factor-1alpha. Thus, LPS selectively modulates the function of chemoattractant receptors in microglia and may promote host response in inflammatory diseases in the CNS.
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bacterial lipopolysaccharide selectively up regulates the function of the Chemotactic Peptide receptor formyl Peptide receptor 2 in murine microglial cells
Journal of Immunology, 2002Co-Authors: Youhong Cui, Wang Hua Gong, Paul Proost, Jozef Van Damme, William J Murphy, Ji Ming WangAbstract:Receptors for the bacterial Chemotactic Peptide fMLP are implicated in inflammation and host defense against microbial infection. We investigated the expression and function of fMLPR in microglial cells, which share characteristics of mononuclear phagocytes and play an important role in proinflammatory responses in the CNS. The expression of the genes encoding formyl Peptide receptor (FPR)1 and FPR2, the high- and low-affinity fMLPR, was detected in a murine microglial cell line N9, but these cells did not respond to Chemotactic agonists known for these receptors. N9 cells incubated with bacterial LPS increased the expression of fMLPR genes and developed a species of specific, but low-affinity, binding sites for fMLP, in association with marked calcium mobilization and chemotaxis responses to fMLP in a concentration range that typically activated the low-affinity receptor FPR2. In addition, LPS-treated N9 cells were chemoattracted by two FPR2-specific agonists, the HIV-1 envelope-derived V3 Peptide, and the 42 aa form of the amyloid β Peptide which is a pathogenic agent in Alzheimer’s disease. Primary murine microglial cells also expressed FPR1 and FPR2 genes, but similar to N9 cells, exhibited FPR2-mediated activation only after LPS treatment. In contrast to its effect on the function of FPR2, LPS reduced N9 cell binding and biological responses to the chemokine stromal cell-derived factor-1α. Thus, LPS selectively modulates the function of chemoattractant receptors in microglia and may promote host response in inflammatory diseases in the CNS.
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novel pathophysiological role of classical Chemotactic Peptide receptors and their communications with chemokine receptors
Immunological Reviews, 2000Co-Authors: Wang Hua Gong, Nancy M Dunlop, Joost J Oppenheim, Weiping Shen, Ji Ming WangAbstract:The bacterial N-formylPeptides, such as N-formyl-Met-Leu-Phe (fMLF), are some of the first identified and most potent chemoattractants for phagocytic leukocytes. Two fMLF receptors, the high affinity formyl Peptide receptor (FPR) and its low affinity variant FPR-like 1 (FPRL1), belong to the seven-transmembrane, Gi protein-coupled receptor superfamily which also includes chemokine receptors. Despite their reaction with bacterial Chemotactic Peptides, the physiological role of these receptors in humans remains unclear. Our recent studies have identified novel exogenous as well as host-derived agonists for FPR and FPRL1. Furthermore, activation of these receptors by their agonists results in desensitization of the receptors for other chemoattractants, including two chemokine receptors, CCR5 and CXCR4, which serve as major co-receptors for HIV-1. These results suggest that FPR and FPRL1 may play important roles not only in host defense and immunological responses but also in the fine tuning of cell activation in the presence of multiple stimuli.
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t21 dp107 a synthetic leucine zipper like domain of the hiv 1 envelope gp41 attracts and activates human phagocytes by using g protein coupled formyl Peptide receptors
Journal of Immunology, 1999Co-Authors: Shao Bo Su, Wang Hua Gong, Nancy M Dunlop, Philip M Murphy, Joost J Oppenheim, Ji Ming WangAbstract:A leucine zipper-like domain, T21/DP107, located in the amino terminus of the ectodomain of gp41, is crucial to the formation of fusogenic configuration of the HIV-1 envelope protein gp41. We report that the synthetic T21/DP107 segment is a potent stimulant of migration and calcium mobilization in human monocytes and neutrophils. The activity of T21/DP107 on phagocytes was pertussis toxin-sensitive, suggesting this Peptide uses Gi-coupled seven-transmembrane receptor(s). Since the bacterial Chemotactic Peptide fMLP partially desensitized the calcium-mobilizing activity of T21/DP107 in phagocytes, we postulated that T21/DP107 might preferentially use a lower affinity fMLP receptor. By using cells transfected to express cloned prototype Chemotactic N -formyl Peptide receptor (FPR) or its variant, FPR-like 1 (FPRL1), we demonstrate that T21/DP107 activates both receptors but has a much higher efficacy for FPRL1. In addition, T21/DP107 at nM concentrations induced migration of FPRL1-transfected human embryonic kidney 293 cells. In contrast, fMLP did not induce significant chemotaxis of the same cells at a concentration as high as 50 μM. Although a lipid metabolite, lipoxin A4, was a high-affinity ligand for FPRL1, it was not reported to induce Ca 2+ mobilization or chemotaxis in FPRL1-transfected cells. Therefore, T21/DP107 is a first Chemotactic Peptide agonist identified thus far for FPRL1. Our results suggest that this Peptide domain of the HIV-1 gp41 may have the potential to activate host innate immune response by interacting with FPR and FPRL1 on phagocytes.