Published online before print May 13, 2004, doi: 10.1161/01.RES.0000132281.78948.65
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© 2004 American Heart Association, Inc.
Cellular Biology |
Platelet 12-Lipoxygenase Activation via Glycoprotein VI
Involvement of Multiple Signaling Pathways in Agonist Control of H(P)ETE Synthesis
From the Department of Medical Biochemistry and Immunology (M.J.C., B.C., O.R.E.W., V.B.O.), University of Wales College of Medicine, Heath Park, Cardiff, Wales; Department of Biochemistry (G.E.J.), University of Cambridge, Tennis Court Road, Cambridge; and the Cardiovascular Research Group (J.M.G., N.E.B.), University of Reading, Whiteknights, Reading, UK.
Correspondence to Dr Valerie B. O’Donnell or to Dr Marcus J. Coffey, PhD, Department of Medical Biochemistry & Immunology, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK. E-mail o-donnellvb{at}cardiff.ac.uk or coffeymj{at}cardiff.ac.uk
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Abstract |
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Lipoxygenases (LOX) contribute to vascular disease and inflammation through generation of bioactive lipids, including 12-hydro(pero)xyeicosatetraenoic acid (12-H(P)ETE). The physiological mechanisms that acutely control LOX product generation in mammalian cells are uncharacterized. Human platelets that contain a 12-LOX isoform (p12-LOX) were used to define pathways that activate H(P)ETE synthesis in the vasculature. Collagen and collagen-related peptide (CRP) (1 to 10 µg/mL) acutely induced platelet 12-H(P)ETE synthesis. This implicated the collagen receptor glycoprotein VI (GPVI), which signals via the immunoreceptor-based activatory motif (ITAM)-containing FcR
chain. Conversely, thrombin only activated at high concentrations (> 0.2 U/mL), whereas U46619 and ADP alone were ineffective. Collagen or CRP-stimulated 12-H(P)ETE generation was inhibited by staurosporine, PP2, wortmannin, BAPTA/AM, EGTA, and L-655238, implicating src-tyrosine kinases, PI3-kinase, Ca2+ mobilization, and p12-LOX translocation. In contrast, protein kinase C (PKC) inhibition potentiated 12-H(P)ETE generation. Finally, activation of the immunoreceptor tyrosine-based inhibitory motif (ITIM)–containing platelet endothelial cell adhesion molecule (PECAM-1) inhibited p12-LOX product generation. This study characterizes a receptor-dependent pathway for 12-H(P)ETE synthesis via the collagen receptor GPVI, which is negatively regulated by PECAM-1 and PKC, and demonstrates a novel link between immune receptor signaling and lipid mediator generation in the vasculature.
Key Words: platelets • lipoxygenase • collagen • collagen receptor glycoprotein VI
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Introduction |
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Lipoxygenases (LOX) catalyze lipid hydroperoxide formation from unsaturated fatty acids.1 Many LOX isoforms are found in the vasculature: some constitutive (eg, p12-LOX in platelets, 5-LOX in neutrophils), others cytokine-inducible (eg, 15-LOX by interleukin-4 (IL-4) in monocytes). Compelling evidence exists for critical involvement of LOXs in vascular and inflammatory diseases including atherosclerosis, cancer, hypertension, and diabetes.2–13
Cellular LOXs require direct activation before product generation occurs. Typically, this requires (1) oxidation of the ferrous iron to an intermediate that abstracts hydrogen from unsaturated lipid and (2) translocation of the cytosolic enzyme to nuclear or plasma membrane. This activation is separate from simple regulation of LOX by fatty acid supply, and its requirement for H(P)ETE synthesis is supported by the following evidence: (1) Ca2+ stimulates membrane binding and arachidonate oxidation by purified 15-LOX in vitro; (2) LOX product generation (in response to Ca2+ ionophore) is inhibited by membrane translocation inhibitors; and (3) 15-LOX in human monocytes oxidizes membrane-bound arachidonate after Ca2+ mobilization, independently of PLA2.14–16 Currently, little is known regarding control of LOX in cells by acute mechanisms. Most studies activate LOX turnover by addition of arachidonate substrate with/without Ca2+ ionophore.17,18 These studies implicate Ca2+-dependent translocation, serine and tyrosine phosphorylation, and LOX association with accessory proteins such as 5-lipoxygenase activating protein (FLAP), although their involvement in LOX activation using physiological agonists is not established.18–23 Acute activation of LOXs has been reported for neutrophil 5-LOX by fMLP and p12-LOX in platelets by collagen; however, the receptors involved and intracellular signaling pathways remain uncharacterized.24–27 Additionally, modulation of LOX activity within cells by agonist-mediated feedback mechanisms has not been examined.
This study utilized washed human platelets as a model to define receptor-dependent and intracellular mechanisms of LOX activation by acute physiological agonists. The data shows (1) collagen or collagen-related peptide (CRP) signaling via glycoprotein VI (GPVI) acutely activates secretion of 12-H(P)ETE, in contrast to thrombin, ADP, and thromboxane receptor (TP), (2) GPVI-stimulated 12-H(P)ETE synthesis requires src-tyrosine kinases, Ca2+ mobilization, and PI3-kinase, and (3) GPVI-stimulated p12-LOX product generation is suppressed by PKC and PECAM-1. These data reveal a central role for the FcR chain-associated GPVI collagen receptor in activation of platelet 12-H(P)ETE generation and implicate immune receptors in modulating LOX in the vasculature.
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Materials and Methods |
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Reagents
Collagen (Type I) was from Mascia Brunelli, Milan, Italy. Arachidonic acid (AA), U46619, L-655238, 12-hydroxyeicosatetraenoic acid (12-HETE), 15-hydroxy-11Z,13E-eicosadienoic acid (15-HEDE), baicalein, and nordihydroguaiaretic acid (NDGA) were from Alexis Chemicals Ltd. Ethylene glycol-O,O'-bis-[2-amino-ethyl]-N,N,N',N',-tetraacetic acid (EGTA), 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM), FURA-2/AM, A23187, PP2, p38-MAP kinase inhibitor (MKI), staurosporine, chelerythrine chloride, and bis-indolymaleimide were from Calbiochem Ltd. All other reagents were from Sigma Ltd, unless otherwise stated.
Preparation of Washed Human Platelets
Platelets were isolated as described28 from consenting donors who were NSAID-free for 2 weeks before donating. Washed platelets were resuspended in Ca2+-freeTyrodes buffer (in mmol/L: 134 NaCl, 12 NaHCO3, 2.9 KCl, 0.34 Na2HPO4, 1 MgCl2, 10 HEPES, 5 glucose, pH 7.4).
Acute Activation of Platelets With Agonists and Sample Preparation for HPLC
3x108 platelets in 100 µL Tyrodes, 1 mmol/L CaCl2, were stimulated with either collagen (1 to 10 µg/mL), CRP (0.05 to 10 µg/mL) (synthesized to a published sequence29), convulxin (1 µg/mL protein concentration) (a kind gift from Dr S.P. Watson, University of Oxford, UK), thrombin (0.04 to 2.0 U/mL), the calcium ionophore, A23187 (1 µmol/L), arachidonic acid (20 µmol/L), the thromboxane mimetic, U46619 (10 µmol/L), or ADP (5 µmol/L) at 37°C with agitation for 10 minutes. Experiments using signaling inhibitors included a 10-minute preincubation step at 37°C before addition of collagen or CRP (both 10 µg/mL). Incubations were stopped by the addition of 200 µL ice-cold methanol and samples spun at 10 000g for 10 minutes at 4°C. Supernatants containing 12-H(P)ETE were recovered and supplemented with 200 ng 15(S)-HEDE per sample as an internal standard.
Reverse Phase HPLC Analysis of Platelet 12-LOX Products
Samples (equivalent to 2x107 cells per sample run) were separated on a 150 mmx4.6 mm, 5 µm C18 ODS2 (Waters Ltd) column using 50% to 90% B over 20 minutes (A=water:acetonitrile:acetic acid, 75:25:0.1, B=methanol:acetonitrile:acetic acid, 60:40:0.1) at 1 mL/min. Absorbance was monitored at 235 nm. Products were identified and quantified using 200 ng 12(S)-HETE standard run in parallel under the same conditions.
Optical Aggregometry
Aggregation of 4x108 washed platelets/mL in response to CRP (0.05 µg/mL) was measured in siliconized-glass cuvettes at 37°C with constant stirring in a PAP4 optical aggregometer (Bio/Data Corp). Platelets were incubated with anti-PECAM-1 antibody (AB468, 1 µg/mL) for 5 minutes, followed by cross-linking for 90 seconds with F(ab')2 fragments of anti-IgG secondary antibody (30 µg/mL). Mouse monoclonal IgG (1 µg/mL) plus F(ab')2 fragments of anti-IgG secondary antibody (30 µg/mL) were utilized as isotype controls. CRP (0.05 µg/mL) was then added and aggregation responses measured.
FURA-2/AM Fluorescence
Washed platelets were incubated at 4x108/mL with 2.5 µmol/L FURA-2/AM for 45 minutes before washing at 800g for 10 minutes. Fluorescence was measured after agonist addition, using a Perkin Elmer 50B fluorescence spectrophotometer at 37°C with stirring (ex, 340 nm, 380 nm; em, 509 nm).
Statistical Analysis
Data are representative of at least 3 separate donors, with samples run in triplicate (Error bars are for mean±SEM). Significance was examined using an unpaired t test where P
0.05 was considered significant (denoted by * on figure). Activity in the presence of inhibitors is expressed % relative to the collagen or CRP response, as appropriate.
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Results |
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Collagen and CRP Stimulate p12-LOX Product Generation in Washed Human Platelets
Incubation of platelets with collagen or CRP led to 12-H(P)ETE synthesis in a dose- and time-dependent manner (Figure 1). 12-H(P)ETE generation in response to agonists was confirmed by coelution with (1) authentic 12-H(P)ETE standard, and (2) 12-H(P)ETE generated after arachidonate activation of platelets. Furthermore, its synthesis was inhibited by LOX inhibitors baicalein or NDGA (Figure 2A). Peroxide analysis of platelet lysates determined that 12-H(P)ETE comprised predominantly 12-HETE, with 12-H(P)ETE content being 2.7±1.5% or 0.7±0.02% for collagen or CRP, respectively (not shown). Collagen treatment showed a lag-phase of approximately 25 seconds before a rapid linear increase over 2 minutes, followed by a slower phase of product generation from 2 to 10 minutes (Figure 1D). CRP showed a similar lag phase with product generation increasing linearly over 1 to 5 minutes (Figure 1F). Synthesis of 12-H(P)ETE did not require addition of exogenous fatty acid or Ca2+ ionophore, indicating that arachidonate substrate originated from internal phospholipid hydrolysis. A crude fraction of venom from Crotalus durissus terrificus containing convulxin, which selectively activates GPVI, also efficiently stimulated 12-H(P)ETE generation (Table).
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Incubation of platelets with thrombin (< 0.2 U/mL) failed to stimulate 12-H(P)ETE synthesis (Table). Nonphysiological concentrations of thrombin, up to 2.0 U/mL did stimulate, although far less than collagen or CRP (not shown). Finally, neither ADP nor the thromboxane A2 mimetic, U46619, activated p12-LOX when added alone (Table). This was in comparison to arachidonate or A23187 activated 12-H(P)ETE synthesis, as previously shown.14
Ca2+ Mobilization Is Necessary but Not Sufficient for GPVI Stimulation of 12-H(P)ETE Synthesis
To examine whether Ca2+ mobilization is required or sufficient for GPVI-stimulated p12-LOX product generation, platelets were first activated in Ca2+-free buffer with EGTA (1 mmol/L) to chelate extracellular Ca2+, with/without BAPTA/AM (10 µmol/L). With EGTA alone, there was a significant 75% decrease in collagen activation of p12-LOX. Additional preincubation with BAPTA/AM virtually abolished 12-H(P)ETE synthesis (Figure 2B). Similarly, a substantial decrease in p12-LOX activity in response to CRP was observed after Ca2+ chelation, although differences were not statistically significant. Separately, Ca2+ mobilization in response to collagen (10 µg/mL), CRP (10 µg/mL), or thrombin (0.1 U/mL) was determined and compared. It was found that thrombin and CRP caused similar elevations in cytosolic Ca2+, which were approximately two-fold higher than collagen (Figure 2C). Because thrombin is ineffective at stimulating 12-H(P)ETE generation at this concentration, Ca2+ mobilization is required, but not sufficient to stimulate p12-LOX turnover.
L-655238 Inhibits CRP-Mediated p12-LOX Product Generation
When incubated with washed platelets, the translocation inhibitor L-655238 (10 µmol/L) significantly inhibited CRP-stimulated 12-H(P)ETE generation (Figure 2D).
CRP and Collagen Stimulation of 12-H(P)ETE Generation Requires Signaling by Tyrosine Kinases
To examine the potential role of tyrosine kinases in p12-LOX activation, staurosporine and the src-family tyrosine kinase inhibitor, PP2, were utilized.30,31 Preincubating platelets with 20 µmol/L staurosporine before collagen or CRP addition caused an approximate 85% inhibition of H(P)ETE generation. (Figure 3A). Preincubating platelets with PP2 (0 to 50 µmol/L) before collagen or CRP addition caused significant dose-dependent inhibition of p12-LOX product generation. (Figure 3B).
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CRP Mediated 12-H(P)ETE Synthesis Is Only Partially Affected by p38-MAP Kinase Inhibition
Preincubating platelets with MKI (100 nmol/L) partially inhibited CRP, but was without effect on collagen-activated H(P)ETE synthesis (Figure 3C).
CRP and Collagen Stimulation of 12-H(P)ETE Synthesis Requires Signaling by PI3-Kinase
After GPVI activation, PI3-kinase binds to the phosphorylated FcR chain and yields PIP3.32 Preincubation of platelets with the PI3-kinase inhibitor wortmannin (100 nmol/L) substantially inhibited collagen and CRP-mediated p12-LOX activity (Figure 3D), implicating this pathway in GPVI-dependent p12-LOX activation.
PKC Inhibitors Potentiate Agonist-Mediated 12-H(P)ETE Generation
PKC is associated with phosphorylation of cytosolic PLA2 and Ca2+ mobilization in platelets.33,34 Two specific PKC inhibitors, bis-indolymaleimide and chelerythrine chloride (1 to 10 µmol/L), potentiated collagen and CRP-mediated p12-LOX. Also, bis-indolymaleimide inclusion with U46619, but not ADP, stimulated 12-H(P)ETE synthesis to levels similar to collagen alone (Figure 4C).
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Requirement of PGHS-1 or ADP for Collagen and CRP Activation of p12-LOX Product Generation
Although unable to directly activate 12-H(P)ETE synthesis alone (Table), secondary mediators including ADP and U46619, may modulate GPVI-dependent activation.35,36 Indomethacin (10 µmol/L) or aspirin (10 mmol/L) were without effect on collagen stimulation, but caused a significant decrease in the CRP response, suggesting that GPVI activation of 12-H(P)ETE generation may involve signaling by TXA2 (Figure 5A). Preincubation of platelets with 1 U/mL apyrase caused significant inhibition of collagen or CRP-stimulated activity (Figure 5B). However inhibition of the collagen response was greater, suggesting ADP signaling may be more important in collagen activation of 12-H(P)ETE synthesis via receptors other than GPVI.
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Alterations in 12-H(P)HETE Esterification Do Not Explain Changes in p12-LOX Product Detection
After their generation, H(P)ETEs can be esterified into membrane phospholipids. To examine whether changes in lipid esterification or hydrolysis in the presence of inhibitors could account for the data herein, samples were analyzed for 12-H(P)ETE before and after alkaline hydrolysis. No significant differences were found for controls or samples treated with PP2, wortmannin, bis-indolymaleimide, or aspirin, indicating that 12-H(P)ETE esterification is not taking place during the time course of our assays (data not shown).
Activation of PECAM-1 in Platelets Inhibits CRP-Mediated p12-LOX Activity
PECAM-1 signaling is stimulated by receptor oligomerization, which is achieved in platelets by antibody cross-linking.37 Stimulation of PECAM-1 before CRP addition caused marked inhibition of platelet aggregation, as previously found (Figure 6A). Similarly PECAM-1 activation inhibited CRP-mediated 12-H(P)ETE synthesis by approximately 50% (Figure 6B). Conversely, isotype control antibody added with cross-linking F(ab')2 or cross-linking F(ab')2 added alone caused potentiation of p12-LOX activity. This reveals PECAM-1 as a negative regulator of GPVI-dependent p12-LOX activation.
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Discussion |
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Using human platelets, a novel receptor-dependent signaling pathway for 12-H(P)ETE synthesis was characterized that utilizes the collagen receptor GPVI. Requirements for GPVI-activation of p12-LOX included src-tyrosine kinases, PI3-kinase, Ca2+ mobilization, and p12-LOX translocation, whereas PKC and PECAM-1 were inhibitory.
Collagen or CRP activated 12-H(P)ETE synthesis in a dose- and time-dependent manner (Figure 1), implicating FcR chain–coupled GPVI as a specific p12-LOX–activating pathway in human platelets. Collagen utilizes several cell surface receptors including: GPVI, 
2ß1 integrin, GP1b, and bound von Willebrand factor.38,39 However, activation by CRP indicates that GPVI signaling alone is sufficient to activate p12-LOX. Conversely, thrombin did not activate unless added in amounts far higher than required for platelet aggregation and degranulation. Finally, neither TP receptor signaling nor ADP could activate 12-H(P)ETE generation alone (Table, Figure 5), although U46619 did stimulate in the presence of the PKC inhibitor, bis-indolymaleimide, suggesting PKC may negatively regulate PGHS-1–dependent activation of p12-LOX activity in platelets (Figure 4C).
GPVI is a platelet-specific collagen receptor whose importance in vascular collagen signaling is highlighted by observations that sequence dimorphisms are associated with increased risk of myocardial infarction.40,41 GPVI closely associates with an ITAM present on the FcR chain that activates tyrosine kinases via adapter molecules such as SLP-76.32,42–44 Activating GPVI triggers PI3-kinase turnover, whose products activate phospholipase C2 (PLC2).45,46 PLC forms DAG and IP3, which activate PKC and Ca2+ mobilization, respectively.47,48 GPVI also causes phosphorylation of p38-MAP kinase, which can directly activate platelet cytosolic PLA2, a potential source of arachidonate substrate for p12-LOX.34,49
To explore requirements for GPVI activation of p12-LOX, signaling inhibitors were also utilized. Potent inhibition of CRP-mediated 12-H(P)ETE synthesis by BAPTA/AM and EGTA implicated Ca2+ mobilization, which could activate p12-LOX by stimulation of p12-LOX translocation (Figure 2B).50,51 In agreement, a translocation inhibitor, L-655238, substantially inhibited GPVI-dependent 12-H(P)ETE synthesis similar to previous reports using collagen (Figure 2D).15 However, Ca2+ mobilization is not in itself sufficient for p12-LOX activation, because a concentration of thrombin that did not cause 12-H(P)ETE synthesis caused significantly greater Ca2+ mobilization than collagen (Figure 2C).
GPVI stimulation of 12-H(P)ETE generation was inhibited by PP2, staurosporine, and wortmannin, implicating src-tyrosine kinases and PI3-kinase in p12-LOX activation (Figure 3). Although these pathways are already known to be activated via GPVI, they have not been previously reported to activate H(P)ETE synthesis in mammalian cells, and provide novel insights into intracellular signaling pathways that modulate LOX product formation. In contrast, an inhibitor of p38 MAP kinase (MKI) did not inhibit collagen, and only slightly inhibited CRP-dependent H(P)ETE generation (Figure 3C).
Secondary mediators such as TXA2 and ADP are involved in collagen signaling in platelets and were found to variably regulate collagen or CRP activation of p12-LOX (Figure 5).52 Apyrase significantly inhibited CRP and collagen-mediated 12-H(P)ETE synthesis, but with a greater effect on collagen activation (Figure 5B). Indomethacin or aspirin partially blocked CRP but not collagen-mediated 12-H(P)ETE generation (Figure 5A). Collectively, this indicates that stimulation of H(P)ETE synthesis via GPVI involves TP signaling, but collagen activation may involve additional receptors signaling independently of the TP receptor and a greater involvement of ADP.38,39
Two PKC inhibitors dose-dependently enhanced collagen/CRP-mediated 12-H(P)ETE synthesis, indicating that PKC negatively regulates GPVI-dependent p12-LOX product generation (Figure 4A). Also, PKC inhibition potentiated U46619 but not ADP stimulation of 12-H(P)ETE generation (Figure 4C). It has been previously shown that PKC is required for U46619 but not ADP-induced platelet activation.53 Inhibition by PKC may involve cross-talk between PKC
or 
and Bruton’s or Fyn tyrosine kinases in platelets, which was recently described.54–56
In the vasculature, the balance between two distinct signaling motifs, termed ITAM and ITIM, has impact on regulating vascular cell function.57 In platelets, ITAM present on the FcR chain coupled to GPVI is activated through phosphorylation by src-family tyrosine kinases. This is inhibited by proteins possessing ITIM, for example, PECAM-1.58,59 Herein, cross-linking studies utilizing antibodies specific for PECAM-1 demonstrated substantial suppression of GPVI-stimulation of 12-H(P)ETE synthesis. Unexpectedly, isotype controls (omitting anti-PECAM-1 antibodies), showed that cross-linking antibodies alone could potentiate CRP stimulation of 12-H(P)ETE synthesis. Although not understood, this may result from interactions of F(ab')2 anti-IgG secondary antibody with sites on the platelet surface unrelated to PECAM-1. The observation that cross-linking using specific anti–PECAM-1 antibody markedly inhibits GPVI-mediated 12-H(P)ETE synthesis demonstrates a novel function for PECAM-1 and a role for ITIM/ITAM-containing immune receptors in modulating 12-H(P)ETE synthesis (Figure 6).
This study presents the first detailed intracellular characterization of a specific receptor-dependent signaling pathway that acutely activates LOX turnover in mammalian cells, and provides a novel link between immune receptor signaling and lipid oxidation in the vasculature.
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Acknowledgments |
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Financial support was from British Heart Foundation (M.J.C., J.M.G., V.B.O.), Wellcome Trust (V.B.O.), and Biotechnology Biological Sciences Research Council (J.M.G.). The authors acknowledge the assistance of Prof S.P. Watson (University of Birmingham, UK) in preparing this manuscript and also Dr P.C. Williams (University of Wales College of Medicine, UK).
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Footnotes |
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Received November 3, 2003; resubmission received March 3, 2004; revised resubmission received April 29, 2004; accepted April 30, 2004.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
1. Taylor GW, Morris HR. Lipoxygenase pathways. Br Med Bull. 1983; 39: 219–222.
2. Kühn H, Belkner J, Zaiss S, Fährenklemper T, Wohfeil S. Involvement of 15-lipoxygenase in early stages of atherogenesis. J Exp Med. 1994; 179: 1903–1911.
3. Yla-Herttuala S, Rosenfeld ME, Parthasarathy S, Glass CK, Sigal E, Sarkioia T, Witztum, JT, Steinberg D. Rabbit and human atherosclerotic lesions contain IgG that recognizes epitopes of oxidized LDL. J Clin Invest. 1991; 87: 1146–1152.[Medline] [Order article via Infotrieve]
4. Folcik VA, Nivar-Aristy RA, Krajewski LP, Cathcardt MK. Lipoxygenase contributes to the oxidation of lipids in human atherosclerotic plaques. J Clin Invest. 1995; 96: 504–510.[Medline] [Order article via Infotrieve]
5. Belkner J, Stender H, Kühn H. The rabbit 15-lipoxygenase preferentially oxygenates LDL cholesterol esters, and this reaction does not require vitamin E. J Biol Chem. 1998; 273: 23225–23232.
6. Sendobry SM, Cornicelli JA, Welch K, Tait B, Trivedi BK, Colbry N, Dyer RD, Feinmark SJ, Daughtery A. Attenuation of diet-induced atherosclerosis in rabbits with a highly selective 15-lipoxygenase inhibitor lacking significant antioxidant properties. Br J Pharmacol. 1997; 12: 1199–1206.[CrossRef]
7. Bleich D, Chen S, Zipser B, Sun D, Funk CD, Nadler JL. Resistance to type 1 diabetes induction in 12-lipoxygenase knockout mice. J Clin Invest. 1999; 103: 1431–1436.[Medline] [Order article via Infotrieve]
8. Cyrus T, Witztum JL, Rader DJ, Tangirala R, Fazio S, Linton MF, Funk CD. Disruption of the 12/15-lipoxygenase gene diminishes atherosclerosis in apo E-deficient mice. J Clin Invest. 1999; 103: 1597–1604.[Medline] [Order article via Infotrieve]
9. Eynard AR, Tremoli E, Caruso D, Magni F, Sirtori CR, Galli G. Platelet formation of 12-hydroxyeicosatetraenoic acid and thromboxane B2 is increased in type IIA hypercholesterolemic subjects. Atherosclerosis. 1986; 60: 61–66.[CrossRef][Medline] [Order article via Infotrieve]
10. Gonzalez-Nunez D, Claria J, Rivera F, Poch E. Increased levels of 12(S)-HETE in patients with essential hypertension. Hypertension. 2001; 37: 334–338.
11. Kühn H, Thiele B. The diversity of the lipoxygenase family. Many sequence data but little information on biological significance. FEBS Lett. 1999; 449: 7–11.[CrossRef][Medline] [Order article via Infotrieve]
12. Nie D, Hillman GG, Geddes T, Tang K, Pierson c, Grignon DJ, Honn KV. Platelet type 12-lipoxygenase regulates angiogenesis in human prostate carcinoma. Adv Exp Med Biol. 1999; 469: 623–630.[Medline] [Order article via Infotrieve]
13. Pidgeon GP, Tang K, Cai YL, Piasentin E, Honn KV. Overexpression of platelet-type 12-lipoxygenase promotes tumor cell survival by enhancing vß3 and vß5 integrin expression. Cancer Res. 2003; 63: 4258–4267.
14. Brinckmann R, Schnurr K, Heydeck D, Rosenbach T, Kolde G, Kühn H. Membrane translocation of 15-lipoxygenase in hematopoietic cells is calcium-dependent and activates the oxygenase activity of the enzyme. Blood. 1998; 91: 64–74.
15. Ozeki Y, Nagamura Y, Ito H, Unemi F, Kimura Y, Igawa T, Kambayashi J, Takahashi Y, Yoshimoto T. An anti-platelet agent, OPC-29030, inhibits translocation of 12-lipoxygenase and 12-hydroxyeicosatetraenoic acid production in human platelets. Br J Pharmacol. 1999; 128: 1699–16704.[CrossRef][Medline] [Order article via Infotrieve]
16. Zhu H, Takahashi Y, Xu W, Kawajiri H, Murakami T, Yamamoto M, Iseki S, Iwasaki T, Hattori H, Yoshimoto T. Low density lipoprotein receptor-related protein-mediated membrane translocation of 12/15-lipoxygenase is required for oxidation of low density lipoprotein by macrophages. J Biol Chem. 2003; 278: 13350–13355.
17. Werz O, Burkert E, Samuelsson B, Radmark O, Steinhilber D. Activation of 5-lipoxygenase by cell stress is calcium independent in human polymorphonuclear leukocytes. Blood. 2002; 99: 1044–1052.
18. Brock TG, McNish RW, Bailie MB, Peters-Golden M. Rapid import of cytosolic 5-lipoxygenase into the nucleus of neutrophils after in vivo recruitment and in vitro adherence. J Biol Chem. 1997; 272: 8276–8280.
19. Werz O, Klemm J, Samuelsson B, Rådmark O. 5-lipoxygenase is phosphorylated by p38 kinase-dependent MAPKAP kinases. Proc Natl Acad Sci U S A. 2000; 97: 5261–5266.
20. Lepley RA, Muskardin DT, Fitzpatrick FA. Tyrosine kinase activity modulates catalysis and translocation of cellular 5-lipoxygenase. J Biol Chem. 1996; 271: 6179–6184.
21. Miller YI, Chang MK, Funk CD, Feramisco JR, Witztum JL. 12/15-lipoxygenase translocation enhances site-specific actin polymerization in macrophages phagocytosing apoptotic cells. J Biol Chem. 2001; 276: 19431–19439.
22. Pouliot M, McDonald PP, Krump E, Mancini JA, McColl SR, Weech PK, Borgeat P. Colocalization of cytosolic phospholipase A2, 5-lipoxygenase, and 5-lipoxygenase-activating protein at the nuclear membrane of A23187-stimulated human neutrophils. Eur J Biochem. 1996; 238: 250–258.[Medline] [Order article via Infotrieve]
23. Wijkander J, O’Flaherty JT, Nixon AB, Wykle RL. 5-Lipoxygenase products modulate the activity of the 85-kDa phospholipase A2 in human neutrophils. J Biol Chem. 1995; 270: 26543–26549.
24. Marleau S, Fruteau de Laclos B, Sanchez AB, Poubelle PE, Borgeat P. Role of 5-lipoxygenase products in the local accumulation of neutrophils in dermal inflammation in the rabbit. J Immunol. 1999; 163: 3449–3458.
25. Malle E, Nimpf J, Leis HJ, Wurm H, Gleispach H, Kostner GM. Cyclooxygenase and lipoxygenase metabolites during platelet aggregation: quantitative measurement by negative ion chemical ionization–gas chromatography/mass spectrometry. Prostaglandins Leukot Med. 1987; 27: 53–70.[CrossRef][Medline] [Order article via Infotrieve]
26. Hwang DH. Characteristics of the formation of the platelet lipoxygenase product from endogenous arachidonic acid. Lipids. 1982; 17: 845–847.[CrossRef][Medline] [Order article via Infotrieve]
27. Sekiya F, Takagi J, Usui T, Kawajiri K, Kobayashi Y, Sato F, Saito Y. 12S-hydroxyeicosatetraenoic acid plays a central role in the regulation of platelet activation. Biochem Biophys Res Comm. 1991; 179: 345–351.[CrossRef][Medline] [Order article via Infotrieve]
28. McNichol A. Platelet preparation and estimation of functional responses. In: Watson SP, Authi KS, eds. Platelets, a Practical Approach. IRL Press; 1996: 1–6.
29. Kehrel B, Wierwille S, Clemetson KJ, Anders O, Steiner M, Knight CG, Farndale RW, Okuma M, Barnes MJ. Glycoprotein VI is a major collagen receptor for platelet activation: it recognizes the platelet-activating quaternary structure of collagen, whereas CD36, glycoprotein IIb/IIIa, and von Willebrand factor do not. Blood. 1998; 91: 491–499.
30. Yanaga F, Poole A, Asselin J, Blake R, Schieven GL, Clark EA, Law CL, Watson SP. Syk interacts with tyrosine-phosphorylated proteins in human platelets activated by collagen and cross-linking of the Fc gamma-IIA receptor. Biochem J. 1995; 311: 471–478.[Medline] [Order article via Infotrieve]
31. Briddon SJ, Watson SP. Evidence for the involvement of p59fyn and p53/56lyn in collagen receptor signalling in human platelets. Biochem J. 1999; 338: 203–209.[CrossRef][Medline] [Order article via Infotrieve]
32. Falet H, Barkalow KL, Pivniouk VI, Barnes MJ, Geha RS, Hartwig JH. Roles of SLP-76, phosphoinositide 3-kinase, and gelsolin in the platelet shape changes initiated by the collagen receptor GPVI/FcR-chain complex. Blood. 2000; 96: 3786–3792.
33. Quinton TM, Kim S, Dangalmaier C, Dorsam RT, Jin J, Daniel JL, Kunapuli SP. Protein kinase C- and calcium-regulated pathways independently synergize with Gi pathways in agonist-induced fibrinogen receptor activation. Biochem J. 2002; 368: 535–543.[CrossRef][Medline] [Order article via Infotrieve]
34. Börsch-Haubold AG, Kramer RM, Watson SP. Phosphorylation and activation of cytosolic phospholipase A2 by 38-kDa mitogen-activated protein kinase in collagen-stimulated human platelets. Eur J Biochem. 1997; 245: 751–759.[Medline] [Order article via Infotrieve]
35. Vezza R, Mezzasoma AM, Venditti G, Gresele P. Prostaglandin endoperoxides and thromboxane A2 activate the same receptor isoforms in human platelets. Thromb Haemost. 2002; 87: 114–121.[Medline] [Order article via Infotrieve]
36. Santos MT, Moscardo A, Valles J, Martinez M, Pinon M, Aznar J, Broekman MJ, Marcus AJ. Participation of tyrosine phosphorylation in cytoskeletal reorganization, IIbß3 integrin receptor activation, and aspirin-insensitive mechanisms of thrombin-stimulated human platelets. Circulation. 2000; 102: 1924–1930.
37. Cicmil M, Thomas JM, Leduc M, Bon C, Gibbins JM. Platelet endothelial cell adhesion molecule-1 signaling inhibits the activation of human platelets. Blood. 2002; 99: 137–144.
38. Shrimpton CN, Borthakur G, Larrucea S, Cruz MA, Lopez J. Localization of the adhesion receptor glycoprotein Ib-IX-V complex to lipid rafts is required for platelet adhesion and activation. J Exp Med. 2002; 196: 1057–1066.
39. Kunicki TJ. The influence of platelet collagen receptor polymorphisms in hemostasis and thrombotic disease. Arterioscler Thromb Vasc Biol. 2002; 22: 14–20.
40. Kunicki TJ, Ruggeri ZM. Platelet collagen receptors and risk prediction in stroke and coronary artery disease. Circulation. 2001; 104: 1451–1453.
41. Croft SA, Samani NJ, Teare MD, Hampton KK, Steeds RP, Channer KS, Daly ME. Novel platelet membrane glycoprotein VI dimorphism is a risk factor for myocardial infarction. Circulation. 2001; 104: 459–1463.
42. Berlanga O, Tulasne D, Bori T, Snell DC, Miura Y, Jung S, Moroi M, Frampton J, Watson SP. The Fc receptor gamma-chain is necessary and sufficient to initiate signalling through glycoprotein VI in transfected cells by the snake C-type lectin, convulxin. Eur J Biochem. 2002; 269: 2951–2960.[Medline] [Order article via Infotrieve]
43. Polanowska-Grabowska R, Geanacopolous M, Gear ARL. Platelet adhesion to collagen via the 2ß1 integrin under arterial flow conditions causes rapid tyrosine phosphorylation of pp125FAK. Biochem J. 1993; 296: 543–547.[Medline]
[Order article via Infotrieve]
44. Watson SP, Asazuma A, Atkinson B, Berlanga O, Best D, Bobe R, Jarvis GE, Marshall S, Snell D, Stafford M, Tulasne D, Wilde J, Wonerow P, Frampton J. The role of ITAM- and ITIM-coupled receptors in platelet activation by collagen. Thromb Haemost. 2001; 86: 276–288.[Medline] [Order article via Infotrieve]
45. Pasquet JM, Bobe R, Gross B, Gratacap MP, Tomlinson MG, Payrastre B, Watson SP. A collagen-related peptide regulates phospholipase C2 via phosphatidylinositol 3-kinase in human platelets. Biochem J. 1999; 342: 171–177.[CrossRef][Medline]
[Order article via Infotrieve]
46. Bobe R, Wilde JI, Mascberger P, Venkateswarlu K, Cullen PJ, Siess W, Watson SP. Phosphatidylinositol 3-kinase-dependent translocation of phospholipase Cgamma2 in mouse megakaryocytes is independent of Bruton tyrosine kinase translocation. Blood. 2001; 97: 678–684.
47. Madani S, Hichami A, Legrand A, Belleville J, Khan NA. Implication of acyl chain of diacylglycerol in activation of different isoforms of protein kinase C. FASEB J. 2001; 15: 2595–25601.
48. Pinton P, Pozzan T, Rizzuto R. The Golgi apparatus is an inositol 1,4,5-trisphosphate-sensitive Ca2+ store, with functional properties distinct from those of the endoplasmic reticulum. EMBO J. 1998; 17: 5298–52308.[CrossRef][Medline] [Order article via Infotrieve]
49. Sundaresan P, Farndale RW. P38 mitogen-activated protein kinase dephosphorylation is regulated by protein phosphatase 2A in human platelets activated by collagen. FEBS Lett. 2002; 528: 139–144.[CrossRef][Medline] [Order article via Infotrieve]
50. Baba A, Sakuma S, Okamoto H, Inoue T, Iwata H. Calcium induces membrane translocation of 12-lipoxygenase in rat platelets. J Biol Chem. 1989; 264: 15790–15795.
51. Hagmann W, Gao X, Zacharek A, Wojciechowski LA, Honn KV. 12-Lipoxygenase in Lewis lung carcinoma cells: molecular identity, intracellular distribution of activity and protein, and Ca(2+)-dependent translocation from cytosol to membranes. Prostaglandins. 1995; 49: 49–62.[CrossRef][Medline] [Order article via Infotrieve]
52. Remijn JA, Wu YP, Jeninga EH, Ijsseldijk MJ, van Willigen G, de Groot PG, Sixma JJ, Nurden AT, Nurden P. Role of ADP receptor P2Y(12) in platelet adhesion and thrombus formation in flowing blood. Arterioscler Thromb Vasc Biol. 2002; 22: 686–691.
53. Paul BZ, Jin J, Kinapuli SP. Molecular mechanism of thromboxane A(2)-induced platelet aggregation. Essential role for p2t(ac) and 2a receptors. J Biol Chem. 1999; 274: 29108–29114.
54. Andrews DA, Yang L, Low PS. Phorbol ester stimulates a protein kinase C-mediated agatoxin-TK-sensitive calcium permeability pathway in human red blood cells. Blood. 2002; 100: 3392–3399.
55. Crosby D, Poole AW. Interaction of Bruton’s tyrosine kinase and protein kinase C in platelets. Cross-talk between tyrosine and serine/threonine kinases. J Biol Chem. 2002; 277: 9958–9965.
56. Crosby D, Poole AW. Physical and functional interaction between protein kinase C delta and Fyn tyrosine kinase in human platelets. J Biol Chem. 2003; 278: 24533–24541.
57. Billadeau DD, Leibson PJ. ITAMs versus ITIMs: striking a balance during cell regulation. J Clin Invest. 2002; 109: 161–168.[CrossRef][Medline] [Order article via Infotrieve]
58. Jones KL, Hughan SC, Dopheide SM, Farndale RW, Jackson SP, Jackson DE. Platelet endothelial cell adhesion molecule-1 is a negative regulator of platelet-collagen interactions. Blood. 2001; 98: 1456–1463.
59. Cicmil M, Thomas JM, Sage T, Barry FA, Leduc M, Bon C, Gibbins JM. Collagen, convulxin, and thrombin stimulate aggregation-independent tyrosine phosphorylation of CD31 in platelets. Evidence for the involvement of Src family kinases. J Biol Chem. 2000; 275: 27339–27347.
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