Structural analysis of purified platelet-activating factor by lipases

Benveniste, Jacques; Couedic, J P Le; Polonsky, Judith; Tencé, Martine

doi:10.1038/269170a0

Cited by 263 publications

(94 citation statements)

References 9 publications

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“…PAF activity was destroyed after base-catalyzed methanolysis or treatment with phospholipase A2, indicating the presence of an ester linkage at the sn-2 position [39, 401. Treatment with phospholipase A1 did not inhibit PAF activity using washed rabbit platelets, suggesting that the PAF detected by the bioassay has an ether bond at the sn-1 position [40]. This result also confirms that the acyl-PAF, synthesized by HUVEC, was not detected by the bioassay.…”

Section: Resultssupporting

confidence: 75%

“…PAF was quantified after extraction and purification by TLC (silica gel 60, F254, Merck) and HPLC (pPorasi1 column, Millipore chromatographic division, Waters) [37]. PAF was characterized by a comparison with synthetic PAF according to the following criteria: (a) the induction of platelet aggregation by a pathway independent from both ADP-mediated and arachidonic acid/thromboxane-A2-mediated pathways; (b) the specificity of platelet aggregation as inferred from the inhibitory effect of 5 pM WEB 2170 [38] and 5 pM CV 3988 171, two different PAF-receptor antagonists: (c) TLC and HPLC behavior and physicochemical characteristics, such as inactivation by strong bases [39] and phospholipase A2 [40], but resistance to phospholipase A1 [40], acids, weak bases and heating for 5 min in boiling water [39]; (d) chemical identity with the synthetic C16-PAF evaluated by a newly developed technique based on HPLC-tandem MS [37]. An API I11 (Perkin Elmer SCIEX) mass spectrometer, with an ionspray articulated source interfaced to a HPLC syringe pump (Applied Biosystems 140A), was used.…”

Section: Assay and Quantification Of Pafmentioning

confidence: 99%

See 1 more Smart Citation

Outer‐membrane porins from Gram‐negative bacteria stimulate platelet‐activating‐factor biosynthesis by cultured human endothelial cells

Tufano

Biancone

Rossano

et al. 1993

European Journal of Biochemistry

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Porins are a family of hydrophobic proteins located in the outer membrane of the cell wall in Gram-negative bacteria. The effect of porins on the biosynthesis of platelet-activating factor (PAF) by cultured human umbilical-cord-vein-derived endothelial cells (HUVEC) was investigated. The results demonstrate that porins were able to induce a dose-dependent synthesis of PAF in HUVEC. PAF, synthesized after stimulation with porins, was mainly cell associated and the synthesis peaked at 15 min, decreasing rapidly thereafter. Experiments with radiolabeled precursors demonstrated that PAF, a 1 -O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, was synthesized via the remodeling pathway involving the acetylation of 1 -O-alkyl-2-lyso-sn-glyceryl-3-phosphorylcholine (2-lysoPAF) generated from l-O-alkyl-2-acyl-sn-glyceryl-3-phosphorylcholine by phospholipase-A2 activity. The activation of phospholipase A2 in HUVEC stimulated by porins was detected by observing the mobilization of [i4C]arachidonic acid. In addition, the activity of acetyl-CoA :l-alkyl-sn-glycero-3-phosphorylcholine 2-0-acetyltransferase was transiently increased in porin-stimulated HUVEC and, after incubation with [3H]CoASAc or [3H]acetate, the [3H]acetyl group was incorporated into newly synthesized PAF. Porins, by forming transmembrane channels, induced a sustained influx of extracellular 45Ca2+ into the cytosol. The activation of PAF synthesis by porins depended on this influx rather than on intracellular calcium mobilization, since PAF synthesis did not occur in the absence of extracellular Ca".It is now recognized that vascular endothelial cells actively participate in the genesis of inflammatory and systemic alterations occurring in sepsis sustained by Gramnegative bacteria. The endothelial-derived vasodilators and the vascular leak resulting from endothelial-cell contraction, either from cytokine-mediated cytoskeletal reorganization or from endothelial injury, may produce blood stasis favoring leukocyte-endothelial adhesion. This may contribute to the systemic alteration which is characteristic of endotoxicheptic shock [l]. Dynamic changes in the surface adhesion molecules of both endothelium and leukocytes are required for sequential adhesion and transmigration of leukocytes through the vascular wall. These changes are promoted by the active

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Section: Resultssupporting

confidence: 75%

Section: Assay and Quantification Of Pafmentioning

confidence: 99%

Outer‐membrane porins from Gram‐negative bacteria stimulate platelet‐activating‐factor biosynthesis by cultured human endothelial cells

Tufano

Biancone

Rossano

et al. 1993

European Journal of Biochemistry

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“…PAF was quantified after extraction and purification by TLC (silica gel plates 60 F254; Merck, Darmstadt, Germany) and HPLC ( Porasil column; Millipore-Waters, Milford, MA) by aggregation of washed rabbit platelets, as previously reported. 17 The biologically active material extracted from cells and supernatants in different experiments was characterized by comparison with synthetic C16 PAF (1-hexadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine; Bachem, Bubendorf, Switzerland) according to the following criteria: 19 (i) induction of platelet aggregation by a pathway independent of both ADP and arachidonic acid/thromboxane A 2 -mediated pathways; (ii) specificity of platelet aggregation, as inferred from the inhibitory effect of 5 M WEB-2170 (Boehringer-Ingelheim, Ingelheim, Germany) or CV-3988 (Takeda, Kyoto, Japan), 2 different PAF-R antagonists; 20,21 (iii) TLC and HPLC behavior and physicochemical characteristics, e.g., inactivation by strong bases and by phospholipase A 2 treatment but resistance to phospholipase A 1 (obtained from Sigma), acids, weak bases and 5 min heating in boiling water.…”

Section: Extraction and Quantification Of Pafmentioning

confidence: 99%

Expression of CD154 on renal cell carcinomas and effect on cell proliferation, motility and platelet‐activating factor synthesis

Bussolati

Russo

Deambrosis

et al. 2002

Intl Journal of Cancer

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CD40 activation by CD154 may trigger diverse cellular responses, ranging from proliferation and differentiation to growth suppression and cell death, in normal and malignant cells. However, the pathophysiologic role of CD154 expressed by tumor cells remains unclear. We have investigated the expression of the CD40-CD154 system in 24 primary cultures derived from renal cell carcinomas, its correlation with tumor stage and its potential functional significance. We found coexpression of CD40 and CD154 in most of the renal carcinoma cell lines. CD154, but not CD40 expression, significantly correlated with tumor stage. Moreover, renal carcinoma cell lines also released the soluble form of CD154 into the supernatant. CD40 engagement by CD154 did not affect apoptosis or survival. On the contrary, CD154 stimulated cell proliferation, motility and production of PAF, a phospholipid mediator of inflammation with angiogenic properties. Key words: CD154; platelet-activating factor; renal carcinoma; CD40; angiogenesis CD154, the ligand of CD40, is a type II integral membrane protein, related to TNF and FasL. 1 Its receptor, CD40, is a 50 kDa transmembrane glycoprotein of the TNF superfamily, which is expressed in a multitude of different cell types, including B cells, monocytes, dendritic cells, endothelial cells, fibroblasts and renal epithelial cells. 2,3 CD40 was originally identified in a bladder carcinoma cell line, 4 and it is also expressed in a number of carcinomas, such as ovarian, nasopharyngeal, bladder, lung, colon and breast carcinomas, whereas normal nonproliferating tissues are CD40-negative. 5 CD40 engagement by CD154 conveys signals regulating diverse cellular responses, ranging from proliferation and differentiation to growth suppression and apoptosis. 6,7 The CD40 cytoplasmic C terminus lacks intrinsic kinase activity and adapter proteins of the TRAF family appear to mediate the activation of CD40-signaling cascades. 8 Despite the large interest, the functional role of CD40 in cancer development remains undetermined. CD40 appears to possess an opposite effect on tumor cell survival and apoptosis. CD40-mediated signaling has been reported to induce apoptosis when expressed in certain transformed cells of mesenchymal origin 9 and in carcinomas of the breast and lung. 10,11 Conversely, Jakobson et al. 12 demonstrated that CD40 stimulation inhibits Fas-mediated apoptosis in human bladder carcinoma cells and we showed a similar protective effect of CD40 in Kaposi's sarcoma cells. 13 Moreover, immunohistochemic studies revealed that detection of CD40 in primary cutaneous malignant melanoma might have negative prognostic value, suggesting its role in tumor progression. 14 CD154 is coexpressed with CD40 in melanoma cells and some carcinomas. 10,11,14 However, the pathophysiologic role of CD40 -CD154 interaction within the tumor cell remains unclear.In the present study, we investigated expression of the CD40 -CD154 system in 24 primary cultures derived from renal clear cell carcinomas, its correlation with tumor st...

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“…Biologically active material extracted from cells and supernatant in different experiments was characterized by comparison with PAF obtained from sensitized rabbit basophils (37) and with synthetic PAF by the following criteria (39): (a) induction of platelet aggregation by a pathway independent from both ADP-and arachidonic acid/thromboxane A2-mediated pathways; (b) specificity of platelet aggregation inferred from the inhibitory effect of 5,M SR163072 (29) and CV3988 (40), two different PAF receptor antagonists ; (c) physicochemical characteristics such as inactivation by strong bases and phospholipase A2, but resistance to phospholipase A, (41), acids, weak bases, and 5 min heating in boiling water. The methods used were previously described in detail (39).…”

Section: Methodsmentioning

confidence: 99%

Tumor necrosis factor/cachectin stimulates peritoneal macrophages, polymorphonuclear neutrophils, and vascular endothelial cells to synthesize and release platelet-activating factor.

Camussi

Bussolino

Salvidio

et al. 1987

The Journal of Experimental Medicine

339

133

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Platelet-activating factor (PAF)' is a mediator of inflammation with a wide range of biological activities (see reference 1 for review) . PAF was initially recognized as a product of IgE-sensitized rabbit basophils (2) and was identified with 1-0-alkyl-2-sn-glyceryl-3-phosphorylcholine (3-5). It was subsequently shown that PAF is synthesized after appropriate stimulation by monocytes/macrophages (6-9), polymorphonuclear neutrophils (7, 10, 11), platelets (12) and endothelial cells (13-15) . PAF induces aggregation and degranulation of platelets (2, 16), stimulates contraction of smooth muscle (17), promotes chemotaxis and granule secretion of neutrophils (18-19) and monocytes (20), increases vascular permeability, and alters the vascular tone (21).It was recently suggested that PAF is a mediator of endotoxic shock (22-24) on the basis of the following observations : (a) PAF is produced during endotoxic shock and experimental sepsis by Gram-negative bacteria (23-25) ; (b) infusion of experimental animals with PAF results in hypotension, decrease in cardiac output, and hypovolemic shock (26-28) ; (c) three PAF receptor antagonists (CV3988, kadsurenone, and SRI 63072) inhibit or reverse endotoxin-induced hypotension and, in this way, prolong the survival of rats (22,23,29) .Tumor necrosis factor/cachectin (TNF) is a mediator of endotoxic shock (30). Because TNF administration to experimental animals reproduces several aspects of PAF infusion (30), it seems possible that PAF is synthesized in response to

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Structural analysis of purified platelet-activating factor by lipases

Cited by 263 publications

References 9 publications

Outer‐membrane porins from Gram‐negative bacteria stimulate platelet‐activating‐factor biosynthesis by cultured human endothelial cells

Outer‐membrane porins from Gram‐negative bacteria stimulate platelet‐activating‐factor biosynthesis by cultured human endothelial cells

Expression of CD154 on renal cell carcinomas and effect on cell proliferation, motility and platelet‐activating factor synthesis

Tumor necrosis factor/cachectin stimulates peritoneal macrophages, polymorphonuclear neutrophils, and vascular endothelial cells to synthesize and release platelet-activating factor.

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