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Juchem G, Weiss DR, Knott M, Senftl A, Förch S, Fischlein T, Kreuzer E, Reichart B, Laufer S, Nees S. Regulation of coronary venular barrier function by blood borne inflammatory mediators and pharmacological tools: insights from novel microvascular wall models. Am J Physiol Heart Circ Physiol 2012; 302:H567-81. [DOI: 10.1152/ajpheart.00360.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesized that postcapillary venules play a central role in the control of the tightness of the coronary system as a whole, particularly under inflammatory conditions. Sandwich cultures of endothelial cells and pericytes of precapillary arteriolar or postcapillary venular origin from human myocardium as models of the respective vascular walls (sandwich cultures of precapillary arteriolar or postcapillary venular origin) were exposed to thrombin and components of the acutely activatable inflammatory system, and their hydraulic conductivity ( LP) was registered. LP of SC-PAO remained low under all conditions (3.24 ± 0.52·10−8cm·s−1·cmH2O−1). In contrast, in the venular wall model, PGE2, platelet-activating factor (PAF), leukotriene B4 (LTB4), IL-6, and IL-8 induced a prompt, concentration-dependent, up to 10-fold increase in LP with synergistic support when combined. PAF and LTB4 released by metabolically cooperating platelets, and polymorphonuclear leucocytes (PMNs) caused selectively venular endothelial cells to contract and to open their clefts widely. This breakdown of the barrier function was preventable and even reversible within 6–8 h by the presence of 50 μM quercetin glucuronide (QG). LTB4 synthesis was facilitated by biochemical involvement of erythrocytes. Platelets segregated in the arterioles and PMNs in the venules of blood-perfused human myocardium (histological studies on donor hearts refused for heart transplantation). Extrapolating these findings to the coronary microcirculation in vivo would imply that the latter's complex functionality after accumulation of blood borne inflammatory mediators can change rapidly due to selective breakdown of the postcapillary venular barrier. The resulting inflammatory edema and venulo-thrombosis will severely impair myocardial performance. The protection afforded by QG could be of particular relevance in the context of cardiosurgical intervention.
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Affiliation(s)
- Gerd Juchem
- Department of Cardiac Surgery, University of Munich (Ludwig Maximilians University), Munich
| | - Dominik R. Weiss
- Department of Transfusion Medicine and Hemostaseology, University of Erlangen-Nuremberg (Friedrich Alexander University), Erlangen
| | - Maria Knott
- Department of Physiology, University of Munich (Ludwig Maximilians University), Munich
| | - Anton Senftl
- Department of Physiology, University of Munich (Ludwig Maximilians University), Munich
| | - Stefan Förch
- Department of Physiology, University of Munich (Ludwig Maximilians University), Munich
| | - Theodor Fischlein
- Department of Cardiac Surgery, Hospital Nuremberg South, Nuremberg; and
| | - Eckart Kreuzer
- Department of Cardiac Surgery, University of Munich (Ludwig Maximilians University), Munich
| | - Bruno Reichart
- Department of Cardiac Surgery, University of Munich (Ludwig Maximilians University), Munich
| | - Stefan Laufer
- Department of Pharmaceutical Chemistry, University of Tuebingen (Eberhard Karls University), Munich, Germany
| | - Stephan Nees
- Department of Physiology, University of Munich (Ludwig Maximilians University), Munich
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Klotz L, Burgdorf S, Dani I, Saijo K, Flossdorf J, Hucke S, Alferink J, Nowak N, Novak N, Beyer M, Mayer G, Langhans B, Klockgether T, Waisman A, Eberl G, Schultze J, Famulok M, Kolanus W, Glass C, Kurts C, Knolle PA. The nuclear receptor PPAR gamma selectively inhibits Th17 differentiation in a T cell-intrinsic fashion and suppresses CNS autoimmunity. ACTA ACUST UNITED AC 2009; 206:2079-89. [PMID: 19737866 PMCID: PMC2757877 DOI: 10.1084/jem.20082771] [Citation(s) in RCA: 258] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
T helper cells secreting interleukin (IL)-17 (Th17 cells) play a crucial role in autoimmune diseases like multiple sclerosis (MS). Th17 differentiation, which is induced by a combination of transforming growth factor (TGF)-beta/IL-6 or IL-21, requires expression of the transcription factor retinoic acid receptor-related orphan receptor gamma t (ROR gamma t). We identify the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) as a key negative regulator of human and mouse Th17 differentiation. PPAR gamma activation in CD4(+) T cells selectively suppressed Th17 differentiation, but not differentiation into Th1, Th2, or regulatory T cells. Control of Th17 differentiation by PPAR gamma involved inhibition of TGF-beta/IL-6-induced expression of ROR gamma t in T cells. Pharmacologic activation of PPAR gamma prevented removal of the silencing mediator for retinoid and thyroid hormone receptors corepressor from the ROR gamma t promoter in T cells, thus interfering with ROR gamma t transcription. Both T cell-specific PPAR gamma knockout and endogenous ligand activation revealed the physiological role of PPAR gamma for continuous T cell-intrinsic control of Th17 differentiation and development of autoimmunity. Importantly, human CD4(+) T cells from healthy controls and MS patients were strongly susceptible to PPAR gamma-mediated suppression of Th17 differentiation. In summary, we report a PPAR gamma-mediated T cell-intrinsic molecular mechanism that selectively controls Th17 differentiation in mice and in humans and that is amenable to pharmacologic modulation. We therefore propose that PPAR gamma represents a promising molecular target for specific immunointervention in Th17-mediated autoimmune diseases such as MS.
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Affiliation(s)
- Luisa Klotz
- Institutes of Molecular Medicine and Experimental Immunology, Department of Neurology, University of Bonn, Bonn 53105, Germany
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Cui L, Isbell MA, Chawengsub Y, Falck JR, Campbell WB, Nithipatikom K. Structural characterization of monohydroxyeicosatetraenoic acids and dihydroxy- and trihydroxyeicosatrienoic acids by ESI-FTICR. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2008; 19:569-585. [PMID: 18296063 PMCID: PMC2373256 DOI: 10.1016/j.jasms.2008.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 01/17/2008] [Accepted: 01/17/2008] [Indexed: 05/25/2023]
Abstract
The fragmentation characteristics of monohydroxyeicosatetraenoic acids and dihydroxy- and trihydroxyeicosatrienoic acids were investigated by electrospray ionization Fourier transform ion cyclotron resonance (FTICR) mass spectrometry using sustained off-resonance irradiation collision-induced dissociation (SORI-CID) and infrared multiphoton dissociation (IRMPD). The fragmentation patterns of these compounds were associated with the number and positions of the hydroxyl substituents. The fragmentation is more complicated with increasing number of the hydroxyl groups of the compounds. In general, the major carbon-carbon cleavage of [M - H](-) ions occurred at the alpha-position to the hydroxyl group, and the carbon-carbon cleavage occurred when there was a double-bond at the beta-position to the hydroxyl group. SORI-CID and IRMPD produced some common fragmentation patterns; however, each technique provided some unique patterns that are useful for structural identification of these compounds. This study demonstrated the application of FTICR via the identification of regioisomers of trihydroxyeicosatrienoic acids in rabbit aorta samples.
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Affiliation(s)
- Lijie Cui
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226
| | - Marilyn A. Isbell
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226
| | - Yuttana Chawengsub
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226
| | - John R. Falck
- Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - William B. Campbell
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226
| | - Kasem Nithipatikom
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226
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Sala A, Profita M, Siena L, Henson PM, Murphy RC, Paternò A, Bonanno A, Riccobono L, Mirabella A, Bonsignore G, Vignola AM. Il-4-induced lipid mediators class switching in human normal mononuclear phagocytes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 525:15-8. [PMID: 12751729 DOI: 10.1007/978-1-4419-9194-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Affiliation(s)
- Angelo Sala
- Dipartimento di Scienze Famacologiche and Center for Cardiopulmonary Pharmacology, Università di Milano, Milan, Italy
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Ballaz S, Mulshine JL. The Potential Contributions of Chronic Inflammation to Lung Carcinogenesis. Clin Lung Cancer 2003; 5:46-62. [PMID: 14596704 DOI: 10.3816/clc.2003.n.021] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A number of lines of evidence suggests that chronic inflammation contributes to the process of carcinogenesis. In this article, this theme is explored with particular emphasis on the involvement of inflammation in the development of lung cancer. A number of molecular pathways activated in chronic inflammation may contribute to lung carcinogenesis. The challenge is to conceptualize a cohesive picture of this complex biology that allows for effective pharmaceutical intervention. Initial therapeutic efforts involve strategies to block single pathways, such as with cyclooxygenase (COX) activity. However, the more that is learned about the consequences of COX activity, the more evident are the relationships of this enzyme to other classes of regulatory molecules such as the potent nuclear factor-kB. In light of this emerging picture, more global intervention strategies, such as with drug combinations, may be essential for success. Further basic study is essential to sort out possible molecular relationships and to permit elucidation of the most critical regulatory circuits. Given the complexity of these molecular interactions, well-designed clinical trials that specifically evaluate the precise effects of particular antiinflammatory drugs on lung carcinogenesis will also be critical to sort out the complexity and to validate successful approaches to arresting lung carcinogenesis.
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Affiliation(s)
- Santiago Ballaz
- Department of Histology and Pathology, Center for Applied Medical Research, University of Navarra, Pamplona, Spain
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Cho H, Gallaher DD, Csallany AS. Nonradiometric HPLC measurement of 13(S)-hydroxyoctadecadienoic acid from rat tissues. Anal Biochem 2003; 318:47-51. [PMID: 12782030 DOI: 10.1016/s0003-2697(03)00140-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A major bioactive metabolite of linoleic acid formed by the action of 15-lipoxygenase-1 is 13(S)-hydroxy-cis-9, trans-11-octadecadienoic acid (13(S)-HODE). 13(S)-HODE is an important intracellular signal agent and is involved in cell proliferation and differentiation in various biological systems. Separation and quantification of 13(S)-HODE from biological materials has previously been achieved only by using radiolabeled linoleic acid as the substrate and two serially connected or two separate HPLC columns to achieve separation of 13(S)-HODE. In the current method, separation and quantification of 13(S)-HODE was achieved by use of a normal-phase HPLC and a solvent system containing hexane/isopropanol/acetonitrile/acetic acid (800/8/30/1, v/v) using isocratic elution with detection at 235 nm. With the currently described method, good separation from unreacted interfering compounds and quantification for 13(S)-HODE were achieved within 35 min with a minimum detection limit of 0.5 ng per injection.
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Affiliation(s)
- H Cho
- Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenue, St. Paul, MN 55108, USA
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Vachier I, Chavis C, Majori M, Farce M, Bousquet J, Godard P, Chanez P. Effects of glucocorticoids on endogenous and transcellular metabolism of eicosanoids in asthma. J Allergy Clin Immunol 2001; 107:824-31. [PMID: 11344349 DOI: 10.1067/mai.2001.113868] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Human blood polymorphonuclear cells, which biosynthesize eicosanoids from the 5-lipoxygenase (5-LO) pathway, are likely to be involved in asthma, in which glucocorticoids represent the first line of therapy. Their effects on leukotriene release after a short course of treatment, which have been reported in several studies, are controversial. OBJECTIVE We sought to investigate whether long-term oral glucocorticoids inhibit lipid mediators from the 5-LO pathway. METHODS Twelve normal control subjects, 29 asthmatic subjects, and 50 glucocorticoid-dependent asthmatic subjects were included in the study. Polymorphonuclear cells were studied for endogenous and transcellular metabolism of eicosanoids. RESULTS Total leukotriene B(4) production was significantly lower in cells from glucocorticoid-dependent asthmatic subjects (mean +/- SD, 177 +/- 26 ng/10(7) cells) than in control subjects (406 +/- 27), untreated asthmatic subjects (421 +/- 34), and asthmatic subjects treated with inhaled glucocorticoids (290 +/- 56). When incubated with arachidonic acid, these polymorphonuclear cells released very low amounts of 5(S)- and 12(S)-hydroxy-eicosatetraenoic acid (HETE), whereas endogenous 15(S)-HETE was found in substantial amounts. The transformation of exogenous 15(S)-HETE into 5(S),15(S)-diHETE and lipoxins was significantly more important in untreated asthmatic subjects than in control subjects and glucocorticoid-dependent asthmatic subjects. CONCLUSION This study showed that long-term oral corticotherapy affects the 5-LO activity and leads to a decrease production of all metabolites in contrast to short-term or inhaled glucocorticoids. This study also questions the site of action of glucocorticoids in regulating the availability of arachidonic acid and potential eicosanoid regulation, as previously held in phospholipase A2 studies.
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Affiliation(s)
- I Vachier
- Clinique des Maladies Respiratoires, CHU-Montpellier INSERM U454, Hôpital Arnaud de Villeneuve, Montpellier, France
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Profita M, Sala A, Riccobono L, Pace E, Paternò A, Zarini S, Siena L, Mirabella A, Bonsignore G, Vignola AM. 15(S)-HETE modulates LTB(4) production and neutrophil chemotaxis in chronic bronchitis. Am J Physiol Cell Physiol 2000; 279:C1249-58. [PMID: 11003605 DOI: 10.1152/ajpcell.2000.279.4.c1249] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We evaluated the levels of 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] and the expression of 15-lipoxygenase (15-LO) mRNA in induced sputum obtained from 10 control and 15 chronic bronchitis subjects. 15(S)-HETE was evaluated by reverse phase high-performance liquid chromatography separation followed by specific RIA. 15-LO mRNA expression was determined by primed in situ labeling. The levels of both soluble and cell-associated 15(S)-HETE resulted significantly higher in chronic bronchitis than in control subjects. The percentage of cells expressing 15-LO mRNA was significantly higher in chronic bronchitis than in control subjects (P < 0.01). Double staining for specific cell type markers and 15-LO mRNA showed macrophages and neutrophils positive for 15-LO, whereas similar staining of peripheral blood neutrophils did not show evidence for 15-LO expression, suggesting that expression of 15-LO in neutrophils takes place on migration into the airways. Because 15(S)-HETE inversely correlated with the percentage of neutrophils in sputum of chronic bronchitis subjects, we studied the effect of 15(S)-HETE on leukotriene B(4) (LTB(4)) production in vitro and evaluated the concentration of LTB(4) in induced sputum and the contribution of LTB(4) to the chemotactic activity of induced sputum samples ex vivo. The results obtained indicate that macrophages and neutrophils present within the airways of chronic bronchitis subjects express 15-LO mRNA; increased basal levels of 15(S)-HETE may contribute to modulate, through the inhibition of 5-lipoxygenase metabolites production, neutrophil infiltration and airway inflammation associated with chronic bronchitis.
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Affiliation(s)
- M Profita
- Istituto di Fisiopatologia Respiratoria, Consiglio Nazionale delle Ricerche, Palermo, Italy
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Profita M, Sala A, Riccobono L, Paternò A, Mirabella A, Bonanno A, Guerrera D, Pace E, Bonsignore G, Bousquet J, Vignola AM. 15-Lipoxygenase expression and 15(S)-hydroxyeicoisatetraenoic acid release and reincorporation in induced sputum of asthmatic subjects. J Allergy Clin Immunol 2000; 105:711-6. [PMID: 10756220 DOI: 10.1067/mai.2000.105122] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Recent evidence shows that 15(S)-hydroxy-eicoisatetraenoic acid (15[S]-HETE) can be released and rapidly reincorporated into cellular lipids. These mechanisms exert several immunoregulatory functions that may be relevant in airway inflammation. OBJECTIVE Our purpose was to evaluate the levels of both soluble and cell-associated 15(S)-HETE and to examine 15-lipoxygenase (15-LO) messenger RNA (mRNA) expression in sputum samples obtained from 10 control and 18 asthmatic subjects. METHODS Levels of 15(S)-HETE were measured by reverse-phase HPLC separation followed by RIA in supernatants and in cell membrane-extracted phospholipids after acid hydrolysis. 15-LO mRNA was evaluated by primed in situ hybridization (PRINS). Combined immunocytochemistry and PRINS was used to identify the phenotype of cells bearing 15-LO transcripts. RESULTS Levels of both soluble and cell-associated 15(S)-HETE were higher in asthmatic than in control subjects (P <.0001). The percentage of cells expressing 15-LO mRNA was higher in asthmatic than in control subjects (P <.01). On double staining for specific cell-type markers and 15-LO mRNA, macrophages were the major source for 15-LO. CONCLUSION This study shows that the induced sputum technique allows the evaluation of 15-LO activity and that soluble, cell-associated 15(S)-HETE and 15-LO levels are higher in asthmatic than in control subjects. In addition, this study indicates that, in induced sputum, airway macrophages are the major source of 15(S)-HETE in asthma.
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Affiliation(s)
- M Profita
- Istituto di Fisiopatologia Respiratoria, Consiglio delle Ricerche, and the Istituto di Medicina Generale e Pneumologia, University of Palermo, Palermo, Italy
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Papadogiannakis N, Barbieri B. Lipoxygenase inhibitors counteract protein kinase C mediated events in human T lymphocyte proliferation. INTERNATIONAL JOURNAL OF IMMUNOPHARMACOLOGY 1997; 19:263-75. [PMID: 9439765 DOI: 10.1016/s0192-0561(97)00068-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Four structurally unrelated inhibitors of lipoxygenase (LO), i.e. nordihydroguaiaretic acid (NDGA), Esculetin, AA861 and 5,8,11,14-eicosatetraynoic acid (ETYA) suppressed mitogen induced proliferation of human peripheral blood lymphocytes in a dose-dependent manner. The degree of suppression was influenced by the type of the mitogenic stimulus. Receptor mediated stimulation, i.e. through phytohemagglutinin or the anti-CD3 antibody OKT3, was overall less susceptible, whereas proliferation initiated by direct activation of protein kinase C (PKC), i.e. through phorbol myristate acetate or indolactam V, was profoundly suppressed (up to 90%). The effect of the LO inhibitors was not due to non-specific interference with intracellular radical intermediates, because AA861 and ETYA showed no radical scavenging activity. Two PKC inhibitors, H-7 and H-8, similarly suppressed lymphocyte proliferation and showed essentially the same suppressive pattern as LO inhibitors. The results clearly indicate that LO product(s) participate in signal transduction mechanisms in T lymphocytes, possibly via stimulation of PKC activity and cell proliferation.
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Affiliation(s)
- N Papadogiannakis
- Karolinska Institutet, Department of Pathology, Huddinge University Hospital, Sweden
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Karanian JW, Kim HY, Yergey JA, Salem N. Lipoxygenase stimulating effects of hydroxylated docosahexaenoates produced by human platelets. Prostaglandins Leukot Essent Fatty Acids 1994; 50:271-8. [PMID: 8066103 DOI: 10.1016/0952-3278(94)90166-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Human platelet suspensions are capable of lipoxygenating docosahexaenoic acid (22:6n3) to an 11(S)-OH-, 14(S)-OH- or 17(S)-OH-22:6n3. The structure and stereochemical purity of these derivatives were confirmed by GC/MS and chiral phase LC analysis. The purified OH-22:6n3 positional isomers which are formed by human platelets were capable of inducing a concentration-dependent contractile response in the guinea-pig lung parenchymal strip at sub-micromolar concentrations. OH-22:6n3 may act in part through stimulation of leukotriene (LT) production as an increase in peptidyl-LT levels (LTC4, LTD4 and LTE4) occurred during the OH-22:6n3-induced contraction in this preparation. Both specific lipoxygenase inhibitors (caffeic acid, 20 uM and NDGA, 50 uM) and a LT receptor antagonist (FPL55712, 20 uM) significantly inhibited the contractile response. Moreover, the OH-22:6n3 positional isomers induced a concentration-dependent increase in LTB4 and LTC4 production in the guinea-pig chopped lung preparation. Other hydroxylated fatty acids and parent fatty acids which were tested (12-OH-20:4n6, 5-OH-20:4n6, 12-OH-20:5n3, 20:5n3 and 22:6n3) did not significantly contract this airway smooth muscle preparation or alter LT production. The hydroxylated 22:6n3 metabolites may modulate airway smooth muscle function in part through the release of peptidyl-LTs from the guinea-pig lung.
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Affiliation(s)
- J W Karanian
- Laboratory of Membrane Biochemistry and Biophysics, DICBR, NIAAA, Bethesda, MD 20892
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LEUKOTRIENE ANTAGONISTS AND INHIBITORS. Immunol Allergy Clin North Am 1993. [DOI: 10.1016/s0889-8561(22)00664-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The present review deals with the role(s) of thymus-eicosanoids in the immune response. It reports the production of cyclooxygenase and lipoxygenase metabolites of arachidonic acid by cells of the thymus microenvironment and the role(s) of these eicosanoids in the differentiation and the maturation of immature T-cells. The possibility that these products may be involved in tolerance to self is discussed. Briefly, it is likely that cells from the monocyte-macrophage lineage which constitute a part of the thymus microenvironment could contribute to the education of immature thymocytes by both presenting self-antigens and producing eicosanoids. Tolerance to self might result from PGE2-driven apoptosis and/or LTB4-induced generation of suppressor cells.
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Affiliation(s)
- M Juzan
- CNRS URA 1456 Université de Bordeaux II, France
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Henneicke-von Zepelin HH, Schröder JM, Smíd P, Reusch MK, Christophers E. Metabolism of arachidonic acid by human epidermal cells depends upon maturational stage. J Invest Dermatol 1991; 97:291-7. [PMID: 1906510 DOI: 10.1111/1523-1747.ep12480558] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Synthesis of 12- and/or 15-HETE by human epidermal cells was investigated after separating basal cells from suprabasal epidermal cell layers. We found that the main metabolite of 3H-arachidonic acid (3H-AA), formed by freshly prepared upper epidermal layers (stratum granulosum and spinosum), upon RP-HPLC co-eluted with authentic 3H-12-HETE. A 3H-15-HETE co-eluting peak selectively occurred in chromatograms obtained from supernatants of fractions containing basal cells. Supernatants of freshly prepared suspensions rich in basal keratinocytes appeared to contain 3H-15-HETE as their main 3H-AA metabolite, by far exceeding the recovered amounts of 3H-12-HETE. Moreover, keratinocytes cultured for 1 week or longer were found to produce predominantly a 3H-AA metabolite co-eluting with 3H-15-HETE. In supernatants of cultured cells, little if any 3H-12-HETE was detectable. Cultured human skin fibroblasts were not found to produce relevant amounts of HETE. Genuine tissue rich in basal cells, i.e., cells of hair follicles, were found to form twice as much 3H-15-HETE as 3H-12-HETE (3H-15-HETE/3H-12-HETE-ratio = 1.9 +/- 0.8; n = 7). Apparently, different epidermal layers are able to produce a characteristic pattern of 3H-AA metabolites. 3H-15-HETE generation seems to be a marker for proliferating keratinocytes, whereas 3H-12-HETE formation appears to be typical for differentiating suprabasal epidermal cells. Our results may explain the heretofore varying patterns of AA-metabolites by keratinocytes reported in the literature.
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Quiroga J, Rodríguez-Sanromán JL, Guarner F, Rodríguez Ortigosa C, Aréjola JM, Prieto J. Inhibitors of the lipoxygenase arachidonic acid pathway impair glycocholate efflux in isolated rat hepatocytes. J Hepatol 1991; 12:302-11. [PMID: 1940258 DOI: 10.1016/0168-8278(91)90831-u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lipoxygenase arachidonic acid metabolites mediate secretory processes in several tissues, but their possible involvement in liver transport functions is still unknown. This study evaluated the influence of the lipoxygenase inhibitor nordihydroguayaretic acid (NDGA), the cyclooxygenase inhibitor indomethacin (INDO), and the dual cyclo and lipoxygenase inhibitors 3-amino-1-[m-(trifluoromethyl)-phenyl]-2-pyrazoline (BW 755c) and eicosatetraynoic acid (ETYA) on the handling of glycocholic acid (GC) by isolated rat hepatocytes. No drug modified cell viability or oxygen consumption in hepatocytes. In 30-min incubations with 50 microM GC the initial rate of GC uptake (V0) in control hepatocytes was 1.15 +/- 0.09 nmol.mg protein-1.min-1. The cellular GC content remained constant from 10 to 30 min (steady-state phase), the 30-min value being 6.63 +/- 0.35 nmol.mg protein-1. NDGA (10-50 microM), BW 755c (25-200 microM) and ETYA (5-100 microM), prevented the steady-state phase occurring, thus determining a progressive accumulation of GC in cells with time. As compared to controls, 50 microM NDGA (+37%, p less than 0.01), 200 microM BW 755c (+39%, p less than 0.01) and 5 microM ETYA (+19%, p less than 0.05) induced the highest increases in the amount of GC in cells at 30 min, in all cases V0 being unchanged. Concentrations of BW 755c and ETYA above those indicated also decreased V0. Both V0 and the amount of cellular GC in the steady-state phase were proportionally decreased by high INDO concentrations (25-100 microM) which did not modify the morphology of the uptake curve. Since experiments with dual and lipoxygenase inhibitors suggested an impairment of GC efflux, the initial rate of GC efflux (V0ef) was measured in hepatocytes preloaded with 50 microM GC and transferred to a GC-free medium. In controls, V0ef was 1.12 +/- 0.12 nmol.mg protein-1.min-1. BW 755c (200 microM) and NDGA (50 microM) reduced V0ef by 45 and 38%, respectively. The kinetic analysis of the effect of 200 microM BW 755c on the efflux process using hepatocytes preloaded with GC from 5 to 200 microM disclosed a non-competitive inhibition. Vmax was reduced from 1.37 +/- 0.15 to 0.89 +/- 0.10 (p less than 0.01), whereas Km was unchanged (3.79 +/- 0.33 vs. 4.25 +/- 0.54, N.S.). In summary, inhibitors of the lipoxygenase arachidonic acid pathway impaired the efflux of GC from isolated rat hepatocytes. The hypothesis is raised that oxidized metabolites of arachidonic acid may participate on the secretion of bile salts in these cells.
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Affiliation(s)
- J Quiroga
- Department of Internal Medicine, University Clinic of Navarra, Pamplona, Spain
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Legrand AB, Lawson JA, Meyrick BO, Blair IA, Oates JA. Substitution of 15-hydroxyeicosatetraenoic acid in the phosphoinositide signaling pathway. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)89485-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Metz SA. Blockade by lipoxygenase inhibitors of Ca2+-dependent insulin secretion from permeabilized rat islets. A molecular mechanism distinct from that of alpha 2-adrenergic agonists. Biochem Pharmacol 1989; 38:1849-62. [PMID: 2567595 DOI: 10.1016/0006-2952(89)90421-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To evaluate the regulation and effects of pancreatic islet lipoxygenase, adult rat islets were permeabilized, using digitonin or staphylococcal alpha-toxin, and then were studied in a medium simulating an intracellular milieu at fixed ambient concentrations of Ca2+. Permeabilized islets retained 12-lipoxygenase activity, as indicated by conversion of tritiated arachidonic acid to a predominant peak of [3H]12-hydroxyeicosatetraenoic acid (12-HETE); this activity was inhibited (89-98%) by the lipoxygenase blockers nordihydroguaiaretic acid (35 microM), BW755c (250 microM) or ETYA (35 microM). Lesser amounts of compounds coeluting with 15- and 11-HETE (but little or no 5-HETE) were formed; however, 11-HETE (and possibly some 15-HETE) was probably synthesized (at least in part) via cyclooxygenase, as suggested by the partial synthesis blockade induced by 50 microM ibuprofen. The production of 12-HETE did not require the presence of Ca2+, Mg2+ or ATP; it also was not stimulated by addition of cyclic AMP, a phorbol ester, or calmodulin. However, it was augmented modestly by provision of a basal cytosolic free Ca2+ concentration of 60-80 nM, with no further increase at physiologically elevated levels of 260-530 nM. Elevations in cytosolic free Ca2+ concentrations induced insulin release which was inhibited by cooling, epinephrine or protein kinase inhibitors and, therefore, was exocytotic in nature. Lipoxygenase inhibitors blocked this insulinotropic effect of calcium at submaximal or saturating Ca2+ concentrations (with or without its potentiation by 12-O-tetradecanoylphorbol-13-acetate, an activator of protein kinase C) by 53-82%. However, they did not reduce the Ca2+-independent secretory effects (at subnanomolar Ca2+ concentrations) of the phorbol ester alone. Similar results were seen using dibutyryl cyclic AMP to activate protein kinase A. The alpha 2-adrenergic agonists epinephrine or clonidine inhibited Ca2+-, TPA- or cyclic AMP-induced insulin release without reducing HETE formation. We conclude that (1) islet lipoxygenase is constitutively expressed and is not physiologically regulated by alpha 2-adrenergic agonism, Ca2+ or protein kinases; (2) lipoxygenase modulates insulin release; HETE production is not merely an epiphenomenon reflecting the activation (or inhibition) of exocytotic secretion; (3) islet lipoxygenase inhibitors reduce insulin secretion, at least in part, by blocking the direct effects of Ca2+ on exocytosis and/or its synergism with Ca2+-binding proteins such as protein kinase C; and (4) these same inhibitors do not directly poison protein kinase C or A, or the exocytotic apparatus.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- S A Metz
- Medicine Service, Denver Veterans Administration Medical Center, CO 80220
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