[12] Automated on-line extraction and profiling of lipoxygenase products of arachidonic acid by high-performance liquid chromatography

Borgeat, Pierre; Picard, Serge; Vallerand, Pierre; Bourgoin, Sylvain G.; Odeimat, A.; Sirois, Pierré; Pe, Poubelle

doi:10.1016/0076-6879(90)87014-t

Cited by 69 publications

(45 citation statements)

References 13 publications

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“…40,41 The profile of 5-lipoxygenase products was characterized by RP-HPLC in long-lived neutrophils. 32 Freshly isolated and long-lived neutrophils incubated in control conditions with the diluent DMSO did not produce any detectable amounts of LTA 4 -derived metabolites (data not shown). Freshly isolated neutrophils responded minimally to fMLP in terms of leukotriene synthesis.…”

Section: Production Of Leukotrienesmentioning

confidence: 99%

“…31 For the determination of 5-lipoxygenase (5-LO)-derived products, cell supernatants were denatured by the addition of 0.5 volume of ice-cold MeOH/CH 3 CN (1:1, v/v) containing 12.5 ng each of PGB 2 and 19-OH-PGB 2 as internal standards, and the samples were processed and analyzed by reversed-phase (RP)-HPLC using an on-line extraction procedure, as described earlier. 32 The 5-LO products leukotriene (LT)B 4 , 20-COOH-LTB 4 , 20-OH-LTB 4 , 6(E)-LTB 4 , 6(E)-12-epi-LTB 4 , peptido-leukotrienes (LTC 4 , LTD 4 and LTE 4 ) and 5-hydroxy-eicosatetraenoic acid (5-HETE) were evaluated. Limits of detection for the different lipoxygenase products were 2-5 ng.…”

Section: Biosynthesis Of Leukotrienesmentioning

confidence: 99%

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Reprogramming of a subpopulation of human blood neutrophils by prolonged exposure to cytokines

Chakravarti

Rusu

Flamand

et al. 2009

Laboratory Investigation

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Essential cells of innate immunity, neutrophils are often considered to be a homogenous population of terminally differentiated cells. During inflammation, neutrophils are extravasated cells exposed to local factors that prolong their survival and activate their production of mediators implicated in disease progression. In this study, a phenotypically distinct subset of human neutrophils that appear after prolonged exposure to cytokines was characterized. Freshly isolated neutrophils from healthy donors were incubated with granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-a and interleukin (IL)-4, three cytokines that are locally present in various inflammatory conditions. Eight to 17% of neutrophils survived beyond 72 h. This subset of non-apoptotic neutrophils, as evaluated by three different markers, was enriched by discontinuous Percoll gradient centrifugation before studying their phenotype. These viable neutrophils showed neoexpression of HLA-DR, CD80 and CD49d. Compared with freshly isolated neutrophils, they responded differentially to second signals similar to formyl-methionyl-leucyl-phenylalanine with three-to four-fold increases in production of superoxide anions and leukotrienes. These cells augmented their phagocytic index by 141%, increased their adhesion to human primary fibroblasts, but reduced their migration in response to chemotactic stimuli and decreased exocytosis of primary and secondary granules. In addition, they produced substantial amounts of IL-8, IL-1Ra and IL-1b. This neutrophil subset had a unique profile of phosphorylation of intracellular signaling molecules. In conclusion, the present identification of a novel neutrophil phenotype highlights the reprogammable character of the neutrophil. This aspect is crucial for our understanding of its contribution to disease pathogenesis and host defense.

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Section: Production Of Leukotrienesmentioning

confidence: 99%

Section: Biosynthesis Of Leukotrienesmentioning

confidence: 99%

Reprogramming of a subpopulation of human blood neutrophils by prolonged exposure to cytokines

Chakravarti

Rusu

Flamand

et al. 2009

Laboratory Investigation

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“…Incubations were stopped by adding 0.5 vol of a cold (220˚C) stop solution [MeOH/MeCN, 1/1 (v/v)] containing 12.5 ng of both 19-OH-PGB2 and PGB2 as internal standards. Samples were denatured overnight (220˚C), then analyzed by reversed phase HPLC using an online extraction procedure (31).…”

Section: Measurement Of Leukotriene Biosynthesis In Human Neutrophilsmentioning

confidence: 99%

Activation of TAK1 by Chemotactic and Growth Factors, and Its Impact on Human Neutrophil Signaling and Functional Responses

Sylvain-Prévost

Ear

Simard

et al. 2015

The Journal of Immunology

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The MAP3 kinase, TAK1, is known to act upstream of IKK and MAPK cascades in several cell types, and is typically activated in response to cytokines (e.g., TNF, IL-1) and TLR ligands. In this article, we report that in human neutrophils, TAK1 can also be activated by different classes of inflammatory stimuli, namely, chemoattractants and growth factors. After stimulation with such agents, TAK1 becomes rapidly and transiently activated. Blocking TAK1 kinase activity with a highly selective inhibitor (5z-7-oxozeaenol) attenuated the inducible phosphorylation of ERK occurring in response to these stimuli but had little or no effect on that of p38 MAPK or PI3K. Inhibition of TAK1 also impaired MEKK3 (but not MEKK1) activation by fMLF. Moreover, both TAK1 and the MEK/ERK module were found to influence inflammatory cytokine expression and release in fMLF- and GM-CSF–activated neutrophils, whereas the PI3K pathway influenced this response independently of TAK1. Besides cytokine production, other responses were found to be under TAK1 control in neutrophils stimulated with chemoattractants and/or GM-CSF, namely, delayed apoptosis and leukotriene biosynthesis. Our data further emphasize the central role of TAK1 in controlling signaling cascades and functional responses in primary neutrophils, making it a promising target for therapeutic intervention in view of the foremost role of neutrophils in several chronic inflammatory conditions.

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“…RP-HPLC analyses were performed using an on-line extraction procedure with detection limits of 0.2 ng at 280 nm and 1 ng at 229 nm [28].…”

Section: Measurement Of 5-lipoxygenase Metabolites By Reverse-phase Hmentioning

confidence: 99%

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

St-Onge

Flamand

Biarc

et al. 2007

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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In the present study, we characterized the generation of prostaglandin (PG)E 2 in human neutrophils. We found that the Ca 2+ -dependent type IV cytosolic phospholipase A 2 (cPLA 2 ) was pivotally involved in the COX-2-mediated generation of PGE 2 in response to a calcium ionophore, as determined by the use of selected PLA 2 inhibitors. PGE 2 biosynthesis elicited by bacterialderived peptides or by phagocytic stimuli acting on cell surface receptors also showed to be dependent on cPLA 2 activity. We then assessed metabolism of unesterified arachidonic acid (AA), and observed that PGE 2 production becomes favored over that of LTB 4 with higher AA concentrations. Withdrawal of calcium prevented the generation of PGE 2 in response to a calcium ionophore but did not affect the up-regulation of COX-2 or its capacity to convert AA, thus limiting its implication at the level of cPLA 2 activation. Of the main eicosanoids produced by neutrophils, only LTB 4 was able to up-regulate COX-2 expression. Finally, the only PGE synthase isoform found in neutrophils is microsomal PGE synthase-1; it co-localized with COX-2 and its expression appeared mainly constitutive. These results highlight key differences in regulatory processes of the 5-LO and COX pathways, and enhance our knowledge at several levels in the PGE 2 biosynthesis in neutrophils.

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[12] Automated on-line extraction and profiling of lipoxygenase products of arachidonic acid by high-performance liquid chromatography

Cited by 69 publications

References 13 publications

Reprogramming of a subpopulation of human blood neutrophils by prolonged exposure to cytokines

Reprogramming of a subpopulation of human blood neutrophils by prolonged exposure to cytokines

Activation of TAK1 by Chemotactic and Growth Factors, and Its Impact on Human Neutrophil Signaling and Functional Responses

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

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