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Abstract
Allergic diseases, such as asthma, rhinitis, eczema and food allergies, are reaching epidemic proportions in both the developed and developing world. Key factors driving these rising trends are increased exposure to sensitizing allergens and reduced stimulation of the immune system during critical periods of development. In allergic disease, there is a polarization of T-lymphocyte responses, and enhanced secretion of cytokines involved in regulation of immunoglobulin E, mast cells, basophils and eosinophils, ultimately leading to inflammation and disease. A clear understanding of the cellular and molecular mechanisms of allergic disease and the complex interplay between genetic and environmental factors will undoubtedly create new opportunities for public health and therapeutic interventions.
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Affiliation(s)
- S T Holgate
- Respiratory, Cell & Molecular Biology Research Division of the School of Medicine, University of Southampton, Southampton General Hospital, UK.
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352
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Mitchell JA, Warner TD. Cyclo-oxygenase-2: pharmacology, physiology, biochemistry and relevance to NSAID therapy. Br J Pharmacol 1999; 128:1121-32. [PMID: 10578123 PMCID: PMC1571744 DOI: 10.1038/sj.bjp.0702897] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cyclo-oxygenase is expressed in cells in two distinct isoforms. Cyclo-oxygenase-1 is present constitutively whilst cyclo-oxygenase-2 is expressed primarily after inflammatory insult. The activity of cyclo-oxygenase-1 and -2 results in the production of a variety of potent biological mediators (the prostaglandins) that regulate homeostatic and disease processes. Inhibitors of cyclo-oxygenase include the nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin, ibuprofen and diclofenac. NSAIDs inhibit cyclo-oxygenase-2 at the site of inflammation, to produce their therapeutic benefits, as well as cyclo-oxygenase-1 in the gastric mucosa, which produces gastric damage. Most recently selective inhibitors of cyclo-oxygenase-2 have been developed and introduced to man for the treatment of arthritis. Moreover, recent epidemiological evidence suggests that cyclo-oxygenase inhibitors may have important therapeutic relevance in the prevention of some cancers or even Alzheimer's disease. This review will discuss how the new advancements in NSAIDs research has led to the development of a new class of NSAIDs that has far reaching implications for the treatment of disease.
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Affiliation(s)
- J A Mitchell
- Unit of Critical Care Medicine, Royal Brompton Hospital, Imperial College School of Medicine, Sydney Street, London SW3 6NP.
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353
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Penrose JF, Austen KF. The biochemical, molecular, and genomic aspects of leukotriene C4 synthase. PROCEEDINGS OF THE ASSOCIATION OF AMERICAN PHYSICIANS 1999; 111:537-46. [PMID: 10591082 DOI: 10.1046/j.1525-1381.1999.99212.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Leukotriene C4 (LTC4) synthase is an 18 kD integral membrane enzyme of the 5-lipoxygenase/LTC4 synthase pathway and is positioned as the pivotal and only committed enzyme for the formation of the cysteinyl leukotrienes. Although its function is to conjugate catalytically LTA4 to reduced glutathione, LTC4 synthase is differentiated from other glutathione S-transferase family members by its lack of amino acid homology, substrate specificity, and kinetics. LTC4 synthase (LTC4S) protein is present in the perinuclear membranes of a limited number of hematopoietic cells involved in allergic inflammation, including mast cells, eosinophils, basophils, and macrophages. The cDNA encodes a monomeric protein of 150 amino acids with three hydrophobic domains interspersed with two hydrophilic loops. Site-directed mutagenic studies reveal that the enzyme functions as a homodimer and that arginine-51 in the first hydrophilic loop, and tyrosine-93 in the second hydrophilic loop, are involved in the acid and base catalysis of LTA4 and glutathione, respectively. Homology and secondary structural predictions indicate that LTC4S is a novel member of a new gene superfamily of integral membrane proteins, each with the capacity to participate in leukotriene biosynthesis. The gene for LTC4S is 2.5 kb in length and is localized on chromosome 5q35, distal to that of the genes for cytokines and receptors important in the development and perpetuation of allergic inflammation. Immunohistochemical studies of mucosal biopsies from the bronchi of aspirin-intolerant asthmatics show that LTC4S is overrepresented in individuals with this phenotype, and this finding correlates with overproduction of cysteinyl leukotrienes and lysine-aspirin bronchial hyperreactivity.
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Affiliation(s)
- J F Penrose
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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354
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Drazen JM. Asthma therapy with agents preventing leukotriene synthesis or action. PROCEEDINGS OF THE ASSOCIATION OF AMERICAN PHYSICIANS 1999; 111:547-59. [PMID: 10591083 DOI: 10.1046/j.1525-1381.1999.t01-1-99242.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Elucidation of the biochemistry of leukotriene production and the pharmacology of its actions has led to the development of a number of therapeutic agents shown to be of value in the treatment of asthma. These agents either prevent the synthesis of the leukotrienes, by preventing the action of the 5-lipoxygenase-activating protein or the catalytic action of the 5-lipoxygenase, or by inhibiting the action of leukotrienes at the CysLT1 receptor. Numerous clinical trials in exercise-induced asthma, allergen-induced asthma, aspirin-induced asthma, and spontaneously occurring asthmatic episodes have indicated that these agents are safe and effective asthma treatments.
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Affiliation(s)
- J M Drazen
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
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355
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May A, Weber A, Gall H, Kaufmann R, Zollner TM. Means of increasing sensitivity of an in vitro diagnostic test for aspirin intolerance. Clin Exp Allergy 1999; 29:1402-11. [PMID: 10520062 DOI: 10.1046/j.1365-2222.1999.00655.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Pseudo-allergic reactions caused by aspirin (acetyl salicylic acid; ASA) often resemble immediate-type hypersensitivity reactions consisting of urticaria and angioedema or rhinoconjunctivitis, asthma and nasal polyps. In the last few years, a new in vitro assay based on determination of sulfidoleucotrienes from isolated leucocytes (cellular allergen stimulation test - CAST) has been introduced for type I allergies and pseudoallergic reactions. In ASA intolerance, there is only limited experience using this assay with - in some studies - only moderate sensitivity. Furthermore, the necessity to use freshly isolated leucocytes from untreated patients is inconvenient for routine settings. OBJECTIVE The purpose of our study was to search for possibilities of increasing the sensitivity of the test and to use stored blood samples which would permit shipping, two requirements for the clinical suitability of this test. PATIENTS AND METHODS Leucotriene release in response to ASA and other non-steroidal anti-inflammatory drugs (NSAIDs) was analysed in 38 ASA-intolerant patients (predominantly airway-related symptoms n = 22; predominantly cutaneous symptoms n = 16) and 50 controls. The diagnosis of ASA intolerance was established by history and placebo-controlled oral challenge tests. RESULTS Using 24 h-stored leucocytes obtained from 10 ASA-intolerant patients and 10 healthy controls there were no significant differences of leucotriene release by resting, ionomycin-, and anti FcepsilonRIalpha-stimulated leucocytes compared with freshly isolated leucocytes. Analysis of ASA + C5a-mediated leucotriene release by stored blood samples in combination with indomethacin- and diclofenac-mediated leucotriene release in ASA-intolerant patients (n = 38) resulted in an increased sensitivity (from 50 to 72.7% in ASA-intolerant patients with predominantly airway-related symptoms and from 81 to 100% in ASA-intolerant patients with predominantly skin symptoms) compared with assays in which only ASA + C5a-mediated leucotriene release has been determined. Moreover, the specificity of the assay remained high (96.7% when analysing different NSAIDs compared with > 99% when analysing only ASA + C5a-mediated leucotriene release). CONCLUSION In vitro stimulation with ASA + C5a leucocyte stimulation with other NSAIDs should be performed to achieve a higher sensitivity. This finding can be explained by the clinical observation of a high ratio of cross-reactivities between the mentioned NSAIDs.
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Affiliation(s)
- A May
- Department of ORL, Germany
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356
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Daffern PJ, Muilenburg D, Hugli TE, Stevenson DD. Association of urinary leukotriene E4 excretion during aspirin challenges with severity of respiratory responses. J Allergy Clin Immunol 1999; 104:559-64. [PMID: 10482828 DOI: 10.1016/s0091-6749(99)70324-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Asthmatics with aspirin- (ASA) sensitive respiratory disease (ASRD) have a spectrum of respiratory reactions during oral ASA challenge that vary in severity and are temporally associated with leukotriene (LT) formation. OBJECTIVE This study investigates the relationship of the severity of ASA-induced respiratory reactions to urinary LTE(4) excretion. METHODS Asthmatics with suspected ASRD underwent oral ASA challenges. Urinary LTE(4) levels were measured at baseline, during the reaction, and after acute ASA desensitization. RESULTS Asthmatics who had respiratory reactions during oral ASA challenges were divided into 3 groups: asthmatics with naso-ocular reactions and <15% decline from baseline FEV(1) values (group 1), asthmatics with a decline in FEV(1) of 20% to 30% (group 2), and asthmatics with a decline in FEV(1) of >30% (group 3). There were no significant differences in age, baseline FEV(1) values, use of inhaled corticosteroids, daily prednisone doses, prednisone bursts, duration of reactions, or average provoking doses of ASA among the groups. At baseline group 3 asthmatics had significantly higher urinary LTE(4) levels than those in groups 1 or 2. At the time of respiratory reaction to ASA, the urinary LTE(4) levels rose significantly in all groups but were significantly greater among group 3 asthmatics compared with those in groups 1 and 2. CONCLUSION The severity of the respiratory reactions during oral ASA challenges was associated with the degree of elevation of baseline LTE(4) synthesis. Our results suggest that asthmatics with ASRD have a spectrum of respiratory tract reactions in which leukotrienes play a distinguishing role.
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Affiliation(s)
- P J Daffern
- Department of Immunology, Scripps Research Institute, La Jolla, CA 92037, USA
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357
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Penrose JF. LTC4 synthase. Enzymology, biochemistry, and molecular characterization. Clin Rev Allergy Immunol 1999; 17:133-52. [PMID: 10436863 DOI: 10.1007/bf02737601] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
LTC4S conjugates reduce glutathione to LTA4 and is positioned as the pivotal and only committed enzyme involved in the formation of cysteinyl LTs. Despite its function as an enzyme that conjugates glutathione to LTA4, it is abundantly clear that LTC4S differs from the classic glutathione S-transferase (GST) families. This distinction is based on narrow substrate specificity, inability to conjugate GSH to xenobiotics, differential susceptibility to inhibitors, lack of homology, and failure to be immunorecognized by specific microsomal GST antibodies. The presence of LTC4S protein is restricted to a limited number of hematopoietic cells to include mast cells, eosinophils, basophils, monocytes/macrophages, and platelets, with the platelet being unique in its lack of the complete biosynthetic pathway for cysteinyl LTs. The purification of the protein and the cloning of the cDNA have demonstrated that the kinetic parameters of LTC4S are similar for the isolated natural or recombinant proteins. The protein is an 18-kDa integral perinuclear membrane enzyme, which is functional as a homodimer. The cDNA encodes a 150 amino-acid polypeptide monomer with three hydrophobic domains interspersed by two hydrophilic loops. Homology and secondary structural predictions have revealed that LTC4S is a member of a novel gene family that includes FLAP, mGST II, and mGST III. Each of these molecules is an integral membrane protein with the capacity to participate in LT biosynthesis: LTC4S as the terminal and only committed enzyme in cysteinyl LT formation, FLAP as an arachidonic acid presentation protein, and mGST II and mGST III as unique dual-function enzymes with primary detoxification functions. Site directed mutagenic studies of LTC4S have revealed that two residues, R51 and Y93, are involved in the acid and base catalysis, respectively, of LTA4 and GSH. Alignment of molecules with LTA4 conjugating ability demonstrates conservation of amino acid residues R51 and Y93, which appear necessary for this specific enzymatic function. The 2.5-Kb gene for human LTC4S contains five small exons and four introns, and the 5' UTR contains consensus sequences for AP-1 and AP-2 sites as well as an SP-1 site. The chromosomal localization of this gene is 5q35, distal to that of cytokine, growth factor, and receptor genes that have relevance to the development of allergic inflammation. Furthermore, there is genetic linkage of this region of human chromosome 5 to atopy and asthma, whereas no linkage exists for the chromosomal localization of the other family members, FLAP and mGST II, distinguishing LTC4S as a unique member of the novel gene family. LTC4S is profoundly overexpressed in the aspirin-induced asthmatic phenotype and correlates with overproduction of cysteinyl LTs and bronchial hyperreactivity to lysine aspirin. Ongoing studies are directed to the genomic regulation and additional polymorphisms within the gene of this pivotal enzyme, as well as to further identification of the amino acid residues central to its catalytic function.
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Affiliation(s)
- J F Penrose
- Harvard Medical School, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
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358
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Devillier P, Baccard N, Advenier C. Leukotrienes, leukotriene receptor antagonists and leukotriene synthesis inhibitors in asthma: an update. Part I: synthesis, receptors and role of leukotrienes in asthma. Pharmacol Res 1999; 40:3-13. [PMID: 10378985 DOI: 10.1006/phrs.1998.0458] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Asthma is a chronic inflammatory disease associated with airflow obstruction. Airflow obstruction results from contraction of airway smooth muscle, mucosal oedema, increased secretion of mucus and infiltration of the airway wall by inflammatory cells, particularly eosinophils. Leukotrienes are thought to contribute to the pathophysiology of asthma. Leukotrienes are synthesised from arachidonic acid by a specific synthesis pathway whose key enzyme is 5-lipoxygenase. Cysteinyl leukotrienes (leukotrienes C4, D4 and E4) have been shown to mimic all the pathologic changes that are characteristic of asthma, whereas leukotriene B4 does not appear to exert biological properties relevant to asthma. Cysteinyl leukotrienes bind to two receptor subtypes: CysLT1 and CysLT2. Most of the biological properties of cysteinyl leukotrienes relevant to asthma are mediated through CysLT1 receptor stimulation.
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Affiliation(s)
- P Devillier
- Laboratoire de Pharmacologie et Toxicologie, Ho@a5pital Maison Blanche, Centre Hospitalier et Universitaire de Reims, 45, rue Cognacq Jay, Reims, Cedex, 51092, France
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359
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Shoji T, Yoshida S, Sakamoto H, Hasegawa H, Nakagawa H, Amayasu H. Anti-inflammatory effect of roxithromycin in patients with aspirin-intolerant asthma. Clin Exp Allergy 1999; 29:950-6. [PMID: 10383596 DOI: 10.1046/j.1365-2222.1999.00551.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Fourteen-membered macrolides, such as roxithromycin, have been reported to exhibit other pharmacological activity including anti-asthmatic effects, besides antibiotic activity. OBJECTIVE This study was designed to investigate the protective effect of roxithromycin on airway responsiveness to the sulpyrine provocation test and to investigate whether this protective activity is associated with a reduction in aspirin-induced excretion of urinary leucotriene E4 (u-LTE4), a marker of cysteinyl leucotriene overproduction that participates in the pathogenesis of aspirin-intolerant asthma. Also, the present study was designed to examine whether or not its anti-asthmatic activity was associated with a reduction in eosinophilic inflammation. METHODS For 8 weeks before analysis, subjects received 150 mg of roxithromycin or matching placebo twice daily. We assessed the effects of pretreatment with roxithromycin on bronchoconstriction precipitated by inhalation of sulpyrine in 14 adult patients with mild or moderate aspirin-intolerant asthma; those who were in stable clinical condition and were hyperresponsive to sulpyrine provocation test were allocated to this study. A double-blind, randomized, crossover design was used. Urinary LTE4 was measured by a combined reverse-phase high-performance liquid chromatography (rp-HPLC) enzyme immunoassay on sulpyrine provocation testing day. Blood and sputum samples were taken in the morning on the sulpyrine provocation testing day. Eosinophil counting and measurement of eosinophilic cationic protein (ECP) were performed. RESULTS After the 8 weeks of treatment with roxithromycin, patients' symptoms, blood eosinophils, serum ECP, sputum eosinophils, and sputum ECP were significantly decreased. On the other hand, values of PC20-sulpyrine did not improve after roxithromycin at all. Furthermore, although challenge with sulpyrine caused a significant increase in u-LTE4, pretreatment with roxithromycin or placebo did not affect excretion of u-LTE4. CONCLUSION Although roxithromycin does not have antileucotriene effects, it has an antibronchial inflammatory effect associated with eosinophilic infiltration. This study raises further interesting therapeutic possibilities and warrants further trials of new approaches to the treatment of aspirin-intolerant asthma.
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Affiliation(s)
- T Shoji
- Department of Internal Medicine, General Takatsu Chuo Hospital, Kawasaki, Japan
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360
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Petkova DK, Pang L, Range SP, Holland E, Knox AJ. Immunocytochemical localization of cyclo-oxygenase isoforms in cultured human airway structural cells. Clin Exp Allergy 1999; 29:965-72. [PMID: 10383598 DOI: 10.1046/j.1365-2222.1999.00573.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cyclo-oxygenase (COX) exists as two isoforms, COX-1, the constitutive isoform, and COX-2, which is inducible by cytokines or inflammatory stimuli and may participate in airway inflammation. OBJECTIVE To determine the basal distribution of COX isoforms, and their regulation by interleukin-1 beta (IL-1beta), bradykinin (BK) and dexamethasone (Dex) in cultured airway structural cells. METHODS We measured COX-1 and COX-2 in cultured human airway smooth muscle (HASM) cells, MRC5 fibroblasts and normal human epithelial cells (NHBE) using immunocytochemical analysis. RESULTS The majority of all types of untreated cultured cells expressed COX-1 (75% of HASM, 75% of MRC5 fibroblasts and 72% of NHBE cells). Fibroblasts and smooth muscle cells showed low constitutive COX-2 expression (2 and 8%, respectively) but this was higher in NHBE cells (28%). IL-1beta (24 h incubation) or BK (4 h incubation) had no effect on COX-1 expression in any of the cells studied. In contrast, there was a two- and 1.5-fold rise in the percentage of NHBE cells expressing COX-2; a 7.5- and sixfold rise in the percentage of HASM cells expressing COX-2 and a 33.5- and 20.5-fold increase in the percentage of fibroblasts expressing COX-2 after IL-1beta or BK treatment, respectively. Pretreatment with dexamethasone abolished IL-1beta- and BK-stimulated COX-2 induction in all cells studied. CONCLUSION COX-1 is expressed constitutively in human airway fibroblasts, smooth muscle and epithelial cells but epithelial cells also show constitutive expression of COX-2. Both IL-1beta and BK induced COX-2 expression in all cells studied and this induction was blocked by dexamethasone. Immunocytochemical techniques can be successfully used to detect the distribution of COX isoforms in cell cultures.
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Affiliation(s)
- D K Petkova
- Respiratory Medicine Unit, City Hospital, Nottingham, UK
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361
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Picado C, Fernandez-Morata JC, Juan M, Roca-Ferrer J, Fuentes M, Xaubet A, Mullol J. Cyclooxygenase-2 mRNA is downexpressed in nasal polyps from aspirin-sensitive asthmatics. Am J Respir Crit Care Med 1999; 160:291-6. [PMID: 10390414 DOI: 10.1164/ajrccm.160.1.9808048] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Exogenous prostaglandin E2 (PGE2) given by inhalation almost completely abrogates aspirin-induced asthma and the accompanying increase in cysteinyl-leukotrienes production. Cyclooxygenase (COX) may be present in cells in both constitutive (COX-1) and inducible (COX-2) forms. To increase the production of the potentially protective endogenous PGE2, COX-2 should be upregulated. We hypothesize that an abnormal regulation of COX-2 will predispose patients with asthma to develop aspirin-intolerant asthma/rhinitis (AIAR). We therefore examined the expression of COX-2 messenger RNA (mRNA) in healthy nasal mucosa (n = 11) and in nasal polyps from both patients with AIAR (n = 8) and those with aspirin-tolerant asthma/rhinitis (ATAR) (n = 20). After total mRNA extraction, COX-1 and COX-2 mRNA expression were measured using a reverse transcriptase (RT)-semiquantitative PCR technique. Hybrid primers of COX-1. glyceraldehyde-3-phosphate dehydrogenase (GAPDH) or COX-2. GAPDH were used to create PCR products that were cloned and used as internal standard controls in the competitive PCR reaction. Results are presented as mean +/- standard error of 10(6) molecules of mRNA/micrograms of total RNA. No differences in COX-1 mRNA expression were found between nasal mucosa and nasal polyps from both patients with ATAR and those with AIAR. However, COX-2 mRNA expression in nasal polyps from the AIAR group (0.38 +/- 0.10) was markedly and significantly lower than in polyps from the ATAR group (2.93 +/- 0. 52, sevenfold, p < 0.0001) and nasal mucosa (2.10 +/- 0.54, sixfold, p < 0.01). These findings suggest that an inadequate COX-2 regulation may be involved in AIAR.
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Affiliation(s)
- C Picado
- Servei de Pneumologia i Al.lèrgia Respiratòria, Hospital Clínic, Departament de Medicina, Universitat de Barcelona, Spain.
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362
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Koshino T, Takano S, Kitani S, Ohshima N, Sano Y, Takaishi T, Hirai K, Yamamoto K, Morita Y. Novel polymorphism of the 5-lipoxygenase activating protein (FLAP) promoter gene associated with asthma. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 1999; 2:32-5. [PMID: 10527888 DOI: 10.1006/mcbr.1999.0147] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The human 5-lipoxygenase activating protein (FLAP) gene is one of the key genes involved in the production of the cysteinyl-leukotrienes. We studied novel polymorphism of the FLAP promoter gene and attempted to clarify the relationship between this polymorphism and asthma. We sequenced the FLAP promoter region, containing the -170 to +46-bp sequence from the translational start codon, and found two homozygotes of novel alleles in the polyadenyl region which showed 21 A repeats and 18 A repeats, respectively. The frequency of the 21 A repeats was 52/71 (73.2%) in asthmatics and 39/71 (54.9%) in control subjects. The difference between these frequencies was statistically significant (P = 0.035). This is the first report of FLAP promoter gene polymorphism associated with asthma. Our data suggest that FLAP promoter gene polymorphism might play a crucial role in the pathogenesis of asthma.
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Affiliation(s)
- T Koshino
- Department of Respiratory Medicine, Graduate School of Medicine, University of Tokyo, Japan.
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363
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Cowburn AS, Holgate ST, Sampson AP. IL-5 Increases Expression of 5-Lipoxygenase-Activating Protein and Translocates 5-Lipoxygenase to the Nucleus in Human Blood Eosinophils. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.1.456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Cysteinyl-leukotrienes are potent bronchoconstrictor mediators synthesized by the 5-lipoxygenase (5-LO) pathway. Eosinophilopoietic cytokines such as IL-5 enhance cysteinyl-leukotriene synthesis in eosinophils in vitro, mimicking changes in eosinophils from asthmatic patients, but the mechanism is unknown. We hypothesized that IL-5 induces the expression of 5-LO and/or its activating protein FLAP in eosinophils, and that this might be modulated by anti-inflammatory corticosteroids. Compared with control cultures, IL-5 increased the proportion of normal blood eosinophils immunostaining for FLAP (65 ± 4 vs 34 ± 4%; p < 0.0001), enhanced immunoblot levels of FLAP by 51 ± 14% (p = 0.03), and quadrupled ionophore-stimulated leukotriene C4 synthesis from 5.7 to 20.8 ng/106 cells (p < 0.02). IL-5 effects persisted for 24 h and were abolished by cycloheximide and actinomycin D. The proportion of FLAP+ eosinophils was also increased by dexamethasone (p < 0.0001). Neither IL-5 nor dexamethasone altered 5-LO expression, but IL-5 significantly increased 5-LO immunofluorescence localizing to eosinophil nuclei. Compared with normal subjects, allergic asthmatic patients had a greater proportion of circulating FLAP+ eosinophils (46 ± 6 vs 27 ± 3%; p < 0.03) and a smaller IL-5-induced increase in FLAP immunoreactivity (p < 0.05). Thus, IL-5 increases FLAP expression and translocates 5-LO to the nucleus in normal blood eosinophils in vitro. This is associated with an enhanced capacity for cysteinyl-leukotriene synthesis and mimics in vivo increases in FLAP expression in eosinophils from allergic asthmatics.
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Affiliation(s)
- Andrew S. Cowburn
- University Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Stephen T. Holgate
- University Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Anthony P. Sampson
- University Medicine, Southampton General Hospital, Southampton, United Kingdom
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364
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Abstract
Antileukotriene drugs inhibit the formation or action of leukotrienes, which are potent lipid mediators generated from arachidonic acid in lung tissue and inflammatory cells. The leukotrienes were discovered in basic studies of arachidonic acid metabolism in leucocytes 20 years ago and were found to display a number of biological activities which may contribute to airway obstruction. Clinical studies with antileukotriene drugs have indeed demonstrated that leukotrienes are significant mediators of airway obstruction evoked by many common trigger factors in asthma. Moreover, treatment trials have established that this new class of drugs has beneficial anti-asthmatic properties, and several antileukotrienes have recently been introduced as new therapy of asthma. This communication presents an overview of the biosynthesis of leukotrienes, their biological effects and clinical effects of antileukotrienes in the treatment of asthama.
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Affiliation(s)
- H E Claesson
- Department of Medical Biophysics and Biochemistry, Karolinska Institute, Stockholm, Sweden.
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365
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Affiliation(s)
- M Sanak
- Department of Medicine, Jagiellonian University School of Medicine, Krakow, Poland
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366
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Affiliation(s)
- J M Drazen
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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367
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Riddick CA, Serio KJ, Hodulik CR, Ring WL, Regan MS, Bigby TD. TGF-β Increases Leukotriene C4 Synthase Expression in the Monocyte-Like Cell Line, THP-1. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.2.1101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The goal of this study was to determine whether cytokines modulate leukotriene C4 (LTC4) synthase expression in mononuclear phagocytes. A panel of cytokines was surveyed for changes in LTC4 synthase mRNA in THP-1 cells. TGF-β1, -2, and -3 had significant stimulatory effects. The addition of TGF-β resulted in a time-dependent increase in LTC4 synthase mRNA at 6 h, which persisted through 48 h. Furthermore, this conditioning resulted in an increase in immunoreactive protein for LTC4 synthase through 7 days. TGF-β conditioning of cells resulted in a time- and dose-dependent increase in stimulated LTC4 synthase activity. Following transient transfection of THP-1 cells with a promoter-reporter construct containing 1.2 kb of the LTC4 synthase promoter, TGF-β treatment resulted in a 2-fold increase in reporter activity. Conditioning with TGF-β did not prolong the half-life of LTC4 synthase mRNA, as assessed by RNase protection assays in actinomycin D-treated cells. Cycloheximide exposure experiments revealed that new protein synthesis was not required for the observed stimulatory effect of TGF-β on LTC4 synthase mRNA. We conclude that LTC4 synthase expression is increased at a transcriptional level by TGF-β in mononuclear phagocytes.
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Affiliation(s)
- Carl A. Riddick
- *Department of Veterans Affairs Medical Center, San Diego, CA 92161, and Department of Medicine, University of California at San Diego, La Jolla, CA 92037
| | - Kenneth J. Serio
- *Department of Veterans Affairs Medical Center, San Diego, CA 92161, and Department of Medicine, University of California at San Diego, La Jolla, CA 92037
| | - Craig R. Hodulik
- *Department of Veterans Affairs Medical Center, San Diego, CA 92161, and Department of Medicine, University of California at San Diego, La Jolla, CA 92037
| | - William L. Ring
- *Department of Veterans Affairs Medical Center, San Diego, CA 92161, and Department of Medicine, University of California at San Diego, La Jolla, CA 92037
| | - Mark S. Regan
- *Department of Veterans Affairs Medical Center, San Diego, CA 92161, and Department of Medicine, University of California at San Diego, La Jolla, CA 92037
| | - Timothy D. Bigby
- *Department of Veterans Affairs Medical Center, San Diego, CA 92161, and Department of Medicine, University of California at San Diego, La Jolla, CA 92037
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368
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Abstract
Leukotriene-receptor antagonists are the first novel class of antiasthma drugs to become available over the past three decades. They have an unique profile in that they are a hybrid of an anti-inflammatory and bronchodilator drug, and they can be taken as a tablet once or twice daily. The published data with leukotriene-receptor antagonists such as montelukast or zafirlukast show good antiasthmatic activity over a wide spectrum of asthma severity either as monotherapy or with inhaled steroids. Another potential spin-off of leukotriene-receptor antagonists is that they also seem to be effective in treating allergic rhinitis, which commonly coexists in patients with asthma. Here I overview the clinical pharmacology of leukotriene antagonists and appraise the published data from clinical trials, and look at the appropriate position of these agents in asthma management guidelines.
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Affiliation(s)
- B J Lipworth
- Department of Clinical Pharmacology & Therapeutics, Ninewells Hospital and Medical School, University of Dundee, UK.
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369
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Chung KF. The role of new asthma treatments. Allergol Int 1998. [DOI: 10.1046/j.1440-1592.1998.00100.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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370
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Dahlén SE. Lipid mediator pathways in the lung: leukotrienes as a new target for the treatment of asthma. Clin Exp Allergy 1998; 28 Suppl 5:141-6; discussion 171-3. [PMID: 9988460 DOI: 10.1046/j.1365-2222.1998.028s5141.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This article summarizes recent evidence supporting that antileukotriene drugs represent a new treatment of asthma which may be particularly effective when combined with drugs that have complementary effects on airway obstruction and inflammation. Firstly, it has been documented that glucocorticosteroids do not inhibit in vivo production of leukotrienes in asthmatics. In line with such findings, addition of antileukotriene drugs to a group of aspirin-intolerant asthmatics maintained on conventional therapy was found to result in an improvement of the asthma over and above the effect of the baseline treatment with inhaled and/or oral glucocorticosteroids. Likewise, in a 6-week trial in a group of severe asthmatics, the asthma deterioration caused by a reduction of the dose of inhaled steroids by half, was prevented by addition of a leukotriene antagonist to the lowered dose of glucocorticosteroids. Current evidence therefore supports that antileukotriene drugs treat components of the pathophysiology which are left unaffected by treatment with glucocorticosteroid. Secondly, in experimental studies as well as in a recent allergen bronchoprovocation study in asthmatics, it has been found that the combination of antihistaminics with antileukotriene drugs will result in a profound inhibition of both the early and the late phase of allergen-induced airway obstruction. It is hypothesized that such a combination may be useful against bronchoconstriction induced by other asthma trigger factors as well as in the treatment of asthma and rhinitits.
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Affiliation(s)
- S E Dahlén
- Experimental Asthma and Allergy Research, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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371
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Behera AK, Kumar M, Matsuse H, Lockey RF, Mohapatra SS. Respiratory syncytial virus induces the expression of 5-lipoxygenase and endothelin-1 in bronchial epithelial cells. Biochem Biophys Res Commun 1998; 251:704-9. [PMID: 9790973 DOI: 10.1006/bbrc.1998.9537] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Respiratory syncytial virus (RSV) infection causes and exacerbates asthma, yet the mechanism by which RSV triggers asthma is poorly understood. Herein, an in vitro model of RSV infection was established using HEp-2 and BEAS-2B bronchial epithelial cell lines, and the expression of 5-lipoxygenase (5-LO), and endothelin-1 (ET-1) was examined. RSV infection increased the expression of 5-LO mRNA and protein in both cell lines, as detected by RT-PCR and western blot analysis, respectively. The levels of leukotrienes also increased in the supernatants of RSV infected cells. Furthermore, RSV infection increased the expression of ET-1 mRNA and protein following RSV infection in a time-dependent manner. It is concluded that RSV infection upregulates the expression of ET-1 and 5-LO in the epithelial cells leading to the production of leukotrienes, which may mediate the consequent exacerbation of asthma.
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Affiliation(s)
- A K Behera
- Department of Internal Medicine, University of South Florida College of Medicine, and James A. Haley VA Hospital, Tampa, FL 33612, USA
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372
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Szczeklik A, Dworski R, Mastalerz L, Prokop A, Sheller JR, Nizankowska E, Cmiel A, Oates JA. Salmeterol prevents aspirin-induced attacks of asthma and interferes with eicosanoid metabolism. Am J Respir Crit Care Med 1998; 158:1168-72. [PMID: 9769277 DOI: 10.1164/ajrccm.158.4.9710043] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We determined the effect of a long acting beta2-agonist, salmeterol, on aspirin-induced asthma (AIA) attacks and urinary release of eicosanoids in a double-blind, placebo-controlled, crossover study in 10 asthmatics sensitive to aspirin. The patients inhaled 50 microgram of salmeterol or placebo 15 min prior to a cumulative challenge with increasing doses of lysine-aspirin (L-ASA) (Part I), and before a single, predetermined dose of L-ASA that caused a 20% fall in FEV1 (PD20) (Part II). Salmeterol significantly attenuated aspirin-precipitated bronchoconstriction and the increase in urinary LTE4. Salmeterol also prevented the decrease in blood eosinophils, and abolished the correlation between the urinary levels of LTE4 and provocative doses of aspirin. In addition, PGD-M, the major urinary metabolite of PGD2, increased after L-ASA inhalation in six of nine subjects; this increase was blocked in all six by salmeterol. The protective effect of salmeterol on aspirin-induced attacks and mediator release suggests that it may be efficacious in aspirin-sensitive asthma.
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Affiliation(s)
- A Szczeklik
- Department of Medicine, Jagiellonian University School of Medicine, Cracow, Poland
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373
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Sampson A, Holgate S. Leukotriene modifiers in the treatment of asthma. Look promising across the board of asthma severity. BMJ (CLINICAL RESEARCH ED.) 1998; 316:1257-8. [PMID: 9554892 PMCID: PMC1113026 DOI: 10.1136/bmj.316.7140.1257] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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