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Li H, Bradbury JA, Edin ML, Gruzdev A, Li H, Graves JP, DeGraff LM, Lih FB, Feng C, Wolf ER, Bortner CD, London SJ, Sparks MA, Coffman TM, Zeldin DC. TXA2 attenuates allergic lung inflammation through regulation of Th2, Th9, and Treg differentiation. J Clin Invest 2024; 134:e165689. [PMID: 38483511 PMCID: PMC11060738 DOI: 10.1172/jci165689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 03/12/2024] [Indexed: 05/02/2024] Open
Abstract
In lung, thromboxane A2 (TXA2) activates the TP receptor to induce proinflammatory and bronchoconstrictor effects. Thus, TP receptor antagonists and TXA2 synthase inhibitors have been tested as potential asthma therapeutics in humans. Th9 cells play key roles in asthma and regulate the lung immune response to allergens. Herein, we found that TXA2 reduces Th9 cell differentiation during allergic lung inflammation. Th9 cells were decreased approximately 2-fold and airway hyperresponsiveness was attenuated in lungs of allergic mice treated with TXA2. Naive CD4+ T cell differentiation to Th9 cells and IL-9 production were inhibited dose-dependently by TXA2 in vitro. TP receptor-deficient mice had an approximately 2-fold increase in numbers of Th9 cells in lungs in vivo after OVA exposure compared with wild-type mice. Naive CD4+ T cells from TP-deficient mice exhibited increased Th9 cell differentiation and IL-9 production in vitro compared with CD4+ T cells from wild-type mice. TXA2 also suppressed Th2 and enhanced Treg differentiation both in vitro and in vivo. Thus, in contrast to its acute, proinflammatory effects, TXA2 also has longer-lasting immunosuppressive effects that attenuate the Th9 differentiation that drives asthma progression. These findings may explain the paradoxical failure of anti-thromboxane therapies in the treatment of asthma.
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Affiliation(s)
- Hong Li
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - J. Alyce Bradbury
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Matthew L. Edin
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Artiom Gruzdev
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Huiling Li
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Joan P. Graves
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Laura M. DeGraff
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Fred B. Lih
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Chiguang Feng
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Erin R. Wolf
- Department of Nephrology, Duke University Medical Center, Durham, North Carolina, USA
| | - Carl D. Bortner
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Stephanie J. London
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
| | - Matthew A. Sparks
- Department of Nephrology, Duke University Medical Center, Durham, North Carolina, USA
| | - Thomas M. Coffman
- Department of Nephrology, Duke University Medical Center, Durham, North Carolina, USA
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| | - Darryl C. Zeldin
- Division of Intramural Research, National Institute of Environmental Health Sciences/NIH, Research Triangle Park, North Carolina, USA
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Hong H, Zhang J, Cao X, Wu Y, Chan TF, Tian XY. Myeloid Bmal1 deletion suppresses the house dust mite-induced chronic lung allergy. J Leukoc Biol 2024; 115:164-176. [PMID: 37170891 DOI: 10.1093/jleuko/qiad047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/13/2023] Open
Abstract
Asthma is the chronic pulmonary inflammatory response that could lead to respiratory failure when allergic reactions exacerbate. It is featured by type 2 immunity with eosinophilic inflammation, mucus, and IgE production, and Th2 cytokine secretion upon repeated challenge of allergens. The symptom severity of asthma displays an apparent circadian rhythm with aggravated airway resistance in the early morning in patients. Bmal1 is the core regulator of the circadian clock, while the regulatory role of Bmal1 in asthma remains unclear. Here, we investigate whether the myeloid Bmal1 is involved in the pathogenesis of house dust mite (HDM)-induced lung allergy. We found that knockdown of Bmal1 in macrophages suppressed the time-of-day variance of the eosinophil infiltration in the alveolar spaces in chronic asthmatic mice. This was accompanied by decreased bronchial mucus production, collagen deposition, and HDM-specific IgE production. However, the suppression effects of myeloid Bmal1 deletion did not alter the allergic responses in short-term exposure to HDM. The transcriptome profile of alveolar macrophages (AMs) showed that Bmal1-deficient AMs have enhanced phagocytosis and reduced production of allergy-mediating prostanoids thromboxane A2 and prostaglandin F2α synthesis. The attenuated thromboxane A2 and prostaglandin F2α may lead to less induction of the eosinophil chemokine Ccl11 expression in bronchial epithelial cells. In summary, our study demonstrates that Bmal1 ablation in macrophages attenuates eosinophilic inflammation in HDM-induced chronic lung allergy, which involves enhanced phagocytosis and reduced prostanoid secretion.
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Affiliation(s)
- Huiling Hong
- Chinese University of Hong Kong, Lo Kwee-Seong Integrated Biomedical Sciences Building, Area 39, Shatin, N.T. Hong Kong SAR, China
| | - Jizhou Zhang
- Science Center, Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR, China
| | - Xiaoyun Cao
- Chinese University of Hong Kong, Lo Kwee-Seong Integrated Biomedical Sciences Building, Area 39, Shatin, N.T. Hong Kong SAR, China
| | - Yalan Wu
- Chinese University of Hong Kong, Lo Kwee-Seong Integrated Biomedical Sciences Building, Area 39, Shatin, N.T. Hong Kong SAR, China
| | - Ting Fung Chan
- Science Center, Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR, China
| | - Xiao Yu Tian
- Chinese University of Hong Kong, Lo Kwee-Seong Integrated Biomedical Sciences Building, Area 39, Shatin, N.T. Hong Kong SAR, China
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Mulvaney EP, Reid HM, Bialesova L, Bouchard A, Salvail D, Kinsella BT. NTP42, a novel antagonist of the thromboxane receptor, attenuates experimentally induced pulmonary arterial hypertension. BMC Pulm Med 2020; 20:85. [PMID: 32252727 PMCID: PMC7132963 DOI: 10.1186/s12890-020-1113-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/12/2020] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND NTP42 is a novel antagonist of the thromboxane prostanoid receptor (TP), currently in development for the treatment of pulmonary arterial hypertension (PAH). PAH is a devastating disease with multiple pathophysiological hallmarks including excessive pulmonary vasoconstriction, vascular remodelling, inflammation, fibrosis, in situ thrombosis and right ventricular hypertrophy. Signalling through the TP, thromboxane (TX) A2 is a potent vasoconstrictor and mediator of platelet aggregation. It is also a pro-mitogenic, pro-inflammatory and pro-fibrotic agent. Moreover, the TP also mediates the adverse actions of the isoprostane 8-iso-prostaglandin F2α, a free-radical-derived product of arachidonic acid produced in abundance during oxidative injury. Mechanistically, TP antagonists should treat most of the hallmarks of PAH, including inhibiting the excessive vasoconstriction and pulmonary artery remodelling, in situ thrombosis, inflammation and fibrosis. This study aimed to investigate the efficacy of NTP42 in the monocrotaline (MCT)-induced PAH rat model, alongside current standard-of-care drugs. METHODS PAH was induced by subcutaneous injection of 60 mg/kg MCT in male Wistar-Kyoto rats. Animals were assigned into groups: 1. 'No MCT'; 2. 'MCT Only'; 3. MCT + NTP42 (0.25 mg/kg BID); 4. MCT + Sildenafil (50 mg/kg BID), and 5. MCT + Selexipag (1 mg/kg BID), where 28-day drug treatment was initiated within 24 h post-MCT. RESULTS From haemodynamic assessments, NTP42 reduced the MCT-induced PAH, including mean pulmonary arterial pressure (mPAP) and right systolic ventricular pressure (RSVP), being at least comparable to the standard-of-care drugs Sildenafil or Selexipag in bringing about these effects. Moreover, NTP42 was superior to Sildenafil and Selexipag in significantly reducing pulmonary vascular remodelling, inflammatory mast cell infiltration and fibrosis in MCT-treated animals. CONCLUSIONS These findings suggest that NTP42 and antagonism of the TP signalling pathway have a relevant role in alleviating the pathophysiology of PAH, representing a novel therapeutic target with marked benefits over existing standard-of-care therapies.
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Affiliation(s)
- Eamon P Mulvaney
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Helen M Reid
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.,UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Lucia Bialesova
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Annie Bouchard
- IPS Therapeutique Inc., 3035 Boulevard Industriel, Sherbrooke, QC, J1L 2T9, Canada
| | - Dany Salvail
- IPS Therapeutique Inc., 3035 Boulevard Industriel, Sherbrooke, QC, J1L 2T9, Canada
| | - B Therese Kinsella
- ATXA Therapeutics Limited, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland. .,UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
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Kim BS, Lee E, Lee MJ, Kang MJ, Yoon J, Cho HJ, Park J, Won S, Lee SY, Hong SJ. Different functional genes of upper airway microbiome associated with natural course of childhood asthma. Allergy 2018; 73:644-652. [PMID: 29052232 DOI: 10.1111/all.13331] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Microbial colonization of the airway plays a role in the pathogenesis of asthma; however, the effect of the upper airway microbiome on childhood asthma is not fully understood. We analyzed the metagenome of airway microbiome to understand the associated role of upper airway microbiome with the natural course of childhood asthma. METHODS Nasopharyngeal swabs were collected from children with asthma, those in asthma remission, and control groups. High-throughput sequencing was used to examine the structure and functional dynamics of the airway microbiome with respect to asthma phenotypes. RESULTS The composition of microbiota differed among healthy control, asthma, and remission groups. The relative abundance of Streptococcus was negatively associated with FEV1% predicted (P = .023) and that of Staphylococcus was negatively associated with methacholine PC20 (P = .013). Genes related to arachidonic acid metabolites, lysine residues, and glycosaminoglycans in the microbiome could be associated with airway inflammation. In particular, genes related to synthesis of anti-inflammatory prostaglandin E2 (PGE2 ) were not detected from the airway microbiome in the asthma group. CONCLUSIONS These data suggest that alterations in the composition and function of the upper airway microbiome could be related with the natural course of asthma in children.
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Affiliation(s)
- B.-S. Kim
- Department of Life Science; Multidisciplinary Genome Institute; Hallym University; Chuncheon Korea
| | - E. Lee
- Department of Pediatrics; Chonnam National University Hospital; Gwangju Korea
| | - M.-J. Lee
- Department of Life Science; Multidisciplinary Genome Institute; Hallym University; Chuncheon Korea
| | - M.-J. Kang
- Asan Institute for Life Science; University of Ulsan College of Medicine; Seoul Korea
| | - J. Yoon
- Department of Pediatrics; Childhood Asthma Atopy Center; Environmental Health Center; Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
| | - H.-J. Cho
- Department of Pediatrics; Childhood Asthma Atopy Center; Environmental Health Center; Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
| | - J. Park
- Interdisciplinary Program of Bioinformatics; Seoul National University; Seoul Korea
| | - S. Won
- Interdisciplinary Program of Bioinformatics; Seoul National University; Seoul Korea
- Department of Public Health Science; Seoul National University; Seoul Korea
- Institute of Health and Environment; Seoul National University; Seoul Korea
| | - S. Y. Lee
- Department of Pediatrics; Childhood Asthma Atopy Center; Environmental Health Center; Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
| | - S. J. Hong
- Department of Pediatrics; Childhood Asthma Atopy Center; Environmental Health Center; Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
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Tamada T, Ichinose M. Leukotriene Receptor Antagonists and Antiallergy Drugs. Handb Exp Pharmacol 2017; 237:153-169. [PMID: 27826703 DOI: 10.1007/164_2016_72] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As one of the candidates of the therapeutic strategy for asthma in addition to inhaled corticosteroids (ICS), leukotriene receptor antagonists (LTRAs) are known to be useful for long-term management of asthma patients complicated by allergic rhinitis (AR) or exercise-induced asthma (EIA). Currently available LTRAs are pranlukast hydrate, zafirlukast, and montelukast. These LTRAs have a bronchodilator action and inhibit airway inflammation, resulting in a significant improvement of asthma symptoms, respiratory function, inhalation frequency of as-needed inhaled β2-agonist, airway inflammation, airway hyperresponsiveness, dosage of ICSs, asthma exacerbations, and patients' QOL. Although cys-LTs are deeply associated with the pathogenesis of asthma, LTRAs alone are less effective compared with ICS. However, the effects of LTRAs in combination with ICS are the same as those of LABAs in combination with ICS in steroid-naïve asthmatic patients. Concerning antiallergy drugs other than LTRAs, some mediator-release suppressants, H1 histamine receptor antagonists (H1RAs), thromboxane A2 (TXA2) inhibitors/antagonists, and Th2 cytokine inhibitor had been used mainly in Japan until the late 1990s. However, the use of these agents rapidly decreased after ICS/long acting beta agonist (LABA) combination was introduced and recommended for the management of asthma in the early 2000s. The effectiveness of other antiallergic agents on asthma management seems to be quite limited, and the safety of oral antiallergic agents has not been demonstrated in fetuses during pregnancy. Further effectiveness studies are needed to determine the true value of these orally administered agents in combination with ICS as an anti-asthma treatment.
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Affiliation(s)
- Tsutomu Tamada
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
| | - Masakazu Ichinose
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
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Pan Y, Li S, Xie X, Li M. Association between thromboxane A2 receptor polymorphisms and asthma risk: A meta-analysis. J Asthma 2016; 53:576-82. [PMID: 27058349 DOI: 10.3109/02770903.2015.1126849] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To determine whether there is an association between thromboxane A2 receptor (TBXA2R) gene polymorphisms (+924C/T and +795C/T) and asthma risk by conducting a meta-analysis. DATA SOURCES Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI) and Wanfang database were searched (updated May 1, 2015). STUDY SELECTIONS Articles evaluating the association between TBXA2R gene polymorphisms and asthma risk were selected. RESULTS A total of 7 studies on +924C/T polymorphism and 6 studies on +795C/T polymorphism were included in this meta-analysis. There was a significant association between TBXA2R +924C/T polymorphism and asthma risk in the recessive model (OR = 1.33, 95% CI = 1.01-1.75, P = 0.045). No significant association between +795C/T polymorphism and asthma risk in the overall population was demonstrated. In subgroup analyzes, significant association was observed in atopic asthma risk in the recessive model (OR = 1.43, 95% CI = 1.01-2.01, P = 0.043), but no significant association was found between TBXA2R +924C/T polymorphism and asthma risk in Asians (OR = 1.14, 95% CI = 0.80-1.63, P = 0.457). TBXA2R +795C/T polymorphism was associated with aspirin-intolerant asthma (AIA) risk when stratified by asthma subphenotype in the allelic model (OR = 1.30, 95% CI = 1.05-1.60, P = 0.014) and dominant model (OR = 1.50, 95% CI = 1.11-2.03, P = 0.008). CONCLUSION Our results suggested that TBXA2R +924C/T polymorphism is associated with asthma risk, and +795C/T polymorphism may be a risk factor for AIA. Larger-scale and well-designed studies are required to validate the association identified in the current meta-analysis.
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Affiliation(s)
- Yilin Pan
- a Department of Respiratory Medicine , The First Affiliated Hospital of Xi'an Jiaotong University , Xi'an, Shaanxi , China
| | - Shaojun Li
- a Department of Respiratory Medicine , The First Affiliated Hospital of Xi'an Jiaotong University , Xi'an, Shaanxi , China
| | - Xinming Xie
- a Department of Respiratory Medicine , The First Affiliated Hospital of Xi'an Jiaotong University , Xi'an, Shaanxi , China
| | - Manxiang Li
- a Department of Respiratory Medicine , The First Affiliated Hospital of Xi'an Jiaotong University , Xi'an, Shaanxi , China
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Veskitkul J, Ruangchira-urai R, Charuvanij S, Pongtanakul B, Udomittipong K, Vichyanond P. Asthma-like symptoms as a presentation of antiphospholipid syndrome. Pediatr Pulmonol 2015; 50:E1-4. [PMID: 25045120 DOI: 10.1002/ppul.23079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 05/17/2014] [Accepted: 05/24/2014] [Indexed: 11/06/2022]
Abstract
We herein report a case of antiphospholipid syndrome (APS) primarily presenting with asthma-like symptoms that had been misdiagnosed as severe asthma. Patients presenting with severe asthma symptoms along with systemic thrombosis should be systematically evaluated for APS.
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Affiliation(s)
- J Veskitkul
- Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Hernandez JM, Janssen LJ. Revisiting the usefulness of thromboxane-A2 modulation in the treatment of bronchoconstriction in asthma. Can J Physiol Pharmacol 2014; 93:111-7. [PMID: 25581104 DOI: 10.1139/cjpp-2014-0364] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Airway smooth muscle (ASM) is the effector cell in the bronchoconstrictory pathway. It is believed that the bronchoconstriction present in asthma is associated with changes in the airway milieu that affect ASM excitation-contraction coupling and Ca(2+)-handling. Asthmatics also react differently to ventilatory mechanical strain. Deep inspiration (DI), which produces bronchodilation in healthy individuals, is less effective in asthmatics, and even enhances bronchoconstriction in moderate to severely affected patients. Our laboratory has previously studied the mechanotransductory pathway of airway stretch-activated contractions (Rstretch) leading to DI-induced bronchoconstriction. We demonstrated the ability of agonists acting through thromboxane A2 (TxA2) receptors to amplify airway Rstretch responses. Despite the involvement of excitatory prostanoids in bronchoconstriction, clinical trials on treatments targeting TxA2-synthase inhibition and TP-receptor antagonism have produced mixed results. Studies in Western populations produced mostly negative results, whereas studies performed in Asian populations showed mostly positive outcomes. In this review, we discuss the role of TxA2-synthase inhibition and TP-receptor antagonism in the treatment of asthmatics. We present information regarding variations in study designs and the possible role of TP-receptor gene polymorphisms in previous study outcome discrepancies. Perhaps future studies should focus on asthmatic patients with DI-induced bronchoconstriction in particular, planting the seed for the individualized treatments for asthmatics.
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Affiliation(s)
- Jeremy Mark Hernandez
- Firestone Institute for Respiratory Health, Father Sean O'Sullivan Research Centre, and Department of Medicine, McMaster University, St. Joseph's Hospital, 50 Charlton Avenue East, Hamilton, ON L8N 4A6, Canada
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Thompson MD, Cole DEC, Capra V, Siminovitch KA, Rovati GE, Burnham WM, Rana BK. Pharmacogenetics of the G protein-coupled receptors. Methods Mol Biol 2014; 1175:189-242. [PMID: 25150871 DOI: 10.1007/978-1-4939-0956-8_9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pharmacogenetics investigates the influence of genetic variants on physiological phenotypes related to drug response and disease, while pharmacogenomics takes a genome-wide approach to advancing this knowledge. Both play an important role in identifying responders and nonresponders to medication, avoiding adverse drug reactions, and optimizing drug dose for the individual. G protein-coupled receptors (GPCRs) are the primary target of therapeutic drugs and have been the focus of these studies. With the advance of genomic technologies, there has been a substantial increase in the inventory of naturally occurring rare and common GPCR variants. These variants include single-nucleotide polymorphisms and insertion or deletions that have potential to alter GPCR expression of function. In vivo and in vitro studies have determined functional roles for many GPCR variants, but genetic association studies that define the physiological impact of the majority of these common variants are still limited. Despite the breadth of pharmacogenetic data available, GPCR variants have not been included in drug labeling and are only occasionally considered in optimizing clinical use of GPCR-targeted agents. In this chapter, pharmacogenetic and genomic studies on GPCR variants are reviewed with respect to a subset of GPCR systems, including the adrenergic, calcium sensing, cysteinyl leukotriene, cannabinoid CB1 and CB2 receptors, and the de-orphanized receptors such as GPR55. The nature of the disruption to receptor function is discussed with respect to regulation of gene expression, expression on the cell surface (affected by receptor trafficking, dimerization, desensitization/downregulation), or perturbation of receptor function (altered ligand binding, G protein coupling, constitutive activity). The large body of experimental data generated on structure and function relationships and receptor-ligand interactions are being harnessed for the in silico functional prediction of naturally occurring GPCR variants. We provide information on online resources dedicated to GPCRs and present applications of publically available computational tools for pharmacogenetic studies of GPCRs. As the breadth of GPCR pharmacogenomic data becomes clearer, the opportunity for routine assessment of GPCR variants to predict disease risk, drug response, and potential adverse drug effects will become possible.
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Affiliation(s)
- Miles D Thompson
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, Canada, M5S 1A8,
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Goulopoulou S, Hannan JL, Matsumoto T, Webb RC. Pregnancy reduces RhoA/Rho kinase and protein kinase C signaling pathways downstream of thromboxane receptor activation in the rat uterine artery. Am J Physiol Heart Circ Physiol 2012; 302:H2477-88. [PMID: 22542618 DOI: 10.1152/ajpheart.00900.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During pregnancy, reduced vascular responses to constrictors contribute to decreased uterine and total vascular resistance. Thromboxane A(2) (TxA(2)) is a potent vasoconstrictor that exerts its actions via diverse signaling pathways, and its biosynthesis increases in preeclampsia. In this study, we hypothesized that maternal vascular responses to TxA(2) will be attenuated via Rho kinase, PKC, p38 MAPK, and ERK1/2 signaling pathways. Isolated ring segments of uterine and small mesenteric arteries from late pregnant (19-21 days) and virgin rats were suspended in a myograph, and isometric force was measured. Pregnancy did not affect uterine and mesenteric artery responses to the TxA(2) analog U-46619 (10(-9)-10(-5) M), but transduction signals associated with these contractions were different between pregnant and nonpregnant rats. Inhibition of Rho kinase (10(-6) M Y-27632) reduced sensitivity to U-46619 in virgin uterine vessels but did not inhibit these contractions in pregnant uterine arteries and had no effect on mesenteric vessels. Treatment of arterial segments with a PKC inhibitor (10(-6) M bisindolylmaleimide I) reduced U-46619-induced contractions in virgin uterine and mesenteric arteries and in pregnant mesenteric arteries. Pregnant uterine arteries, however, were unresponsive to PKC inhibition. Inhibition of ERK1/2 (10(-5) M PD-98059) and p38 MAPK (10(-5) M SB-203580) reduced U46619-induced contractions in nonpregnant vessels and in pregnant uterine and mesenteric vessels. These data suggest that normal pregnancy does not affect uterine and mesenteric contractile responses to TxA(2) but reduces the contribution of Rho kinase and PKC signaling pathways to these contractions in the uterine vasculature. In contrast, the role of ERK1/2 and p38 MAPK in U-46619-induced uterine contractions remains unchanged with pregnancy. TxA(2)-associated transduction signals and its regulators might present potential targets for the development of new treatments for preeclampsia and other pregnancy-associated vascular diseases.
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Affiliation(s)
- Styliani Goulopoulou
- Department of Physiology, Georgia Health Sciences University, Augusta, Georgia 30912, USA.
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Hernandez JM, Janssen LJ. Thromboxane Prostanoid Receptor Activation Amplifies Airway Stretch-Activated Contractions Assessed in Perfused Intact Bovine Bronchial Segments. J Pharmacol Exp Ther 2011; 339:248-56. [DOI: 10.1124/jpet.111.182246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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12
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Chitano P. Models to understand contractile function in the airways. Pulm Pharmacol Ther 2011; 24:444-51. [PMID: 21511049 DOI: 10.1016/j.pupt.2011.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 04/04/2011] [Accepted: 04/07/2011] [Indexed: 11/25/2022]
Abstract
Although the role of contractile function in the airways is controversial, there is general consensus on the importance of airway smooth muscle (ASM) as a therapeutic target for diseases characterized by airway obstruction, such as asthma or chronic obstructive pulmonary disease. Indeed, the use of bronchodilators to relax ASM is the most common and effective practice to treat airflow obstruction. Excessive pathologic bronchoconstriction may originate from primary alterations of ASM mechanical function and/or from the effects exerted on ASM function by disease processes, such as inflammation and remodeling. An in depth knowledge of the potentially multiple mechanisms that distinctively regulate primary and secondary alterations in ASM contractile function would be essential for the development of new therapeutic approaches aimed at preventing the occurrence or reducing the severity of bronchoconstriction. The present review discusses studies that have addressed the mechanisms of altered ASM contractile function in models of airway hyperresponsiveness. Although not comprehensively, in the present review, animal models of intrinsic airway hyperresponsiveness, normal ontogenesis, and allergic sensitization are analyzed in the attempt to summarize the current knowledge on regulatory mechanisms of ASM contractile function in health and disease. Studies in human ASM and the need for additional models to understand contractile function in the airways are also discussed.
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Affiliation(s)
- Pasquale Chitano
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
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Palikhe NS, Kim SH, Lee HY, Kim JH, Ye YM, Park HS. Association of thromboxane A2 receptor (TBXA2R) gene polymorphism in patients with aspirin-intolerant acute urticaria. Clin Exp Allergy 2010; 41:179-85. [PMID: 21070398 DOI: 10.1111/j.1365-2222.2010.03642.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The thromboxane A2 receptor (TBXA2R) is a potent broncho- and vaso-constrictor and is associated with leukotriene synthesis. Polymorphisms in the TBXA2R gene have been linked to atopy, asthma, and atopic dermatitis. This study evaluated the association between genetic TBXA2R variants and the development of acetyl salicylic acid (ASA)-intolerant acute urticaria (AIAU). METHODS AIAU patients (n=167), ASA-intolerant chronic urticaria (AICU) patients (n=149), and healthy controls (NC) (n=265) were included. All patients were enrolled at Ajou University Hospital in Suwon, Korea. Two TBXA2R polymorphisms (-4684T>C and 795T>C) were genotyped by primer extension using a SNAPshot ddNTP primer extension kit. Luciferase activity was measured using a dual-luciferase reporter assay kit. An electrophoretic mobility shift assay (EMSA) was performed using a nuclear extract from a human mast cell line (HMC-1). RESULTS Genetic association data demonstrated that compared with NC subjects, AIAU patients had a significantly higher frequency of the homozygous TT genotype of TBXA2R-4684T>C (P=0.005, P(corr) =0.03). No differences were identified between the AICU and the NC groups. Luciferase activity, reflecting promoter activity, was significantly lower with the TBXA2R-4684T-containing construct than with the -4684C-containing construct (P<0.001); the activity decreased further upon co-transfection with ETS-like gene transcription factor-1 (ELK-1) (P=0.012). EMSA revealed that the -4684T allele produced a specific shifted band, with a greater affinity than that produced by the -4684C allele. CONCLUSION AND CLINICAL RELEVANCE These results suggest that the TBXA2R-4684T allele may be associated with lower TBXA2R expression, which may contribute to the development of the AIAU phenotype.
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Affiliation(s)
- N S Palikhe
- Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea
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14
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Lei Y, Cao Y, Zhang Y, Edvinsson L, Xu CB. Enhanced airway smooth muscle cell thromboxane receptor signaling via activation of JNK MAPK and extracellular calcium influx. Eur J Pharmacol 2010; 650:629-38. [PMID: 21036122 DOI: 10.1016/j.ejphar.2010.10.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 10/14/2010] [Accepted: 10/15/2010] [Indexed: 12/22/2022]
Abstract
Thromboxane is a key inflammatory mediator and potent airway constrictor. It acts on thromboxane A(2) (TP) receptors and contributes to airway inflammation and airway hyperresponsiveness that is the characteristic feature of asthma. The present study was designed to study TP receptor signaling in airway smooth muscle cells by using an organ culture model and a set of selective pharmacological inhibitors for mitogen-activated protein kinase (MAPK) and calcium signal pathways. Western-blot, immunohistochemistry, myograph and a selective TP receptor agonist U46619 were used for examining TP receptor signal proteins and function. Organ culture of rat bronchial segments for up to 48 h induces a time-dependently increased airway contractile response to U46619. This indicates that organ culture increases TP receptor signaling in the airway smooth muscle cells. The enhanced bronchial contraction was attenuated by the inhibition of c-Jun N-terminal kinase (JNK) MAPK activity, chelation of extracellular calcium and calcium channel blocker nifedipine, suggesting that JNK MAPK activity and elevated intracellular calcium level are required for the TP receptor signaling. In conclusion, airway smooth muscle cell TP receptor signaling occurs via JNK MAPK activity and the elevation of extracellular calcium influx, which may provide knowledge for understanding the signaling pathway responsible for the modulation of TP receptor mediated airway hyperresponsiveness to thromboxane.
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Affiliation(s)
- Ying Lei
- Division of Experimental Vascular Research, Institute of Clinical Science in Lund, Lund University, Lund, Sweden
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15
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Dogné JM, Wouters J, Rolin S, Michaux C, Pochet L, Durant F, Delarge J, Masereel B. Design, synthesis and biological evaluation of a sulfonylcyanoguanidine as thromboxane A2 receptor antagonist and thromboxane synthase inhibitor. J Pharm Pharmacol 2010; 53:669-80. [PMID: 11370706 DOI: 10.1211/0022357011775992] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The synthesis and the structure of N-isopropyl-N′-[2-(3′-methylphenylamino)-5-nitrobenzenesulfonyl] urea (14) was drawn from two thromboxane A2 receptor antagonists structurally related to torasemide. Compound 14 showed an IC50 value of 22 nm for the thromboxane A2 (TXA2) receptor of human washed platelets. Compound 14 prevented platelet aggregation induced by arachidonic acid (0.6 mm) and U-46619 (1 μm) with an IC50 value of 0.45 and 0.15 μm, respectively. Moreover, 14 relaxed the rat isolated aorta and guinea-pig trachea precontracted by U-46619, a TXA2 agonist. Its efficacy (IC50) was 20.4 and 5.47 nm, respectively. Finally, 14 (1 μm) completely inhibited TXA2 synthase of human platelets. The pKa value and the crystallographic data of 14 were determined and used to propose an interaction model between the TXA2 antagonists related to torasemide and their receptor.
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Affiliation(s)
- J M Dogné
- Department of Pharmacy, University of Namur, Belgium
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16
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Mubarak KK. A review of prostaglandin analogs in the management of patients with pulmonary arterial hypertension. Respir Med 2010; 104:9-21. [DOI: 10.1016/j.rmed.2009.07.015] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 06/25/2009] [Accepted: 07/19/2009] [Indexed: 10/20/2022]
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Abstract
OBJECTIVE To consider the mechanisms that may link asthma and major depressive disorder (MDD). Asthma and MDD co-occur at higher rates than expected, but whether this reflects shared underlying pathophysiological mechanisms is not known. METHODS A review of the epidemiological data linking asthma and MDD was conducted and the possible biological mechanisms that could account for the high rate of this comorbidity were reviewed. RESULTS MDD occurs in almost half of patients with asthma assessed in tertiary care centers. Dysregulation of the hypothalamic pituitary adrenal axis may predispose people to both MDD and asthma, and similar alterations in the immune, autonomic nervous, and other key systems are apparent and may contribute to this increased risk of co-occurrence. CONCLUSIONS High rates of MDD in asthma may result from the stress of chronic illness, the medications used to treat it, or a combination of the two. The high level of co-occurrence may also reflect dysregulation of certain stress-sensitive biological processes that contribute to the pathophysiology of both conditions.
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18
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Clarke DL, Dakshinamurti S, Larsson AK, Ward JE, Yamasaki A. Lipid metabolites as regulators of airway smooth muscle function. Pulm Pharmacol Ther 2008; 22:426-35. [PMID: 19114116 DOI: 10.1016/j.pupt.2008.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 11/18/2008] [Accepted: 12/10/2008] [Indexed: 02/02/2023]
Abstract
Compelling evidence identifies airway smooth muscle (ASM) not only as a target but also a cellular source for a diverse range of mediators underlying the processes of airway narrowing and airway hyperresponsiveness in diseases such as asthma. These include the growing family of plasma membrane phospholipid-derived polyunsaturated fatty acids broadly characterised by the prostaglandins, leukotrienes, lipoxins, isoprostanes and lysophospholipids. In this review, we describe the enzymatic and non-enzymatic biosynthetic pathways of these lipid mediators and how these are influenced by drug treatment, oxidative stress and airways disease. Additionally, we outline their cognate receptors, many of which are expressed by ASM. We describe potential deleterious and protective roles for these lipid mediators in airway inflammatory and remodelling processes by describing their effects on diverse functions of ASM in asthma that have the potential to contribute to asthma pathogenesis and symptoms. These functions include contractile tone development, cytokine and extracellular matrix production, and cellular proliferation and migration.
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Affiliation(s)
- Deborah L Clarke
- Respiratory Pharmacology, National Heart and Lung Institute, Imperial College, London, UK
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19
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Mahajan SG, Mehta AA. Effect of Moringa oleifera Lam. seed extract on ovalbumin-induced airway inflammation in guinea pigs. Inhal Toxicol 2008; 20:897-909. [PMID: 18686107 DOI: 10.1080/08958370802027443] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
To determine the therapeutic potential of herbal medicine Moringa oleifera Lam. family: Moringaceae in the control of allergic diseases, the efficacy of the ethanolic extract of the seeds of the plant (MOEE) against ovalbumin (OVA)-induced airway inflammation in guinea pigs was examined. During the experimental period, the test drugs (MOEE or dexamethasone) were administered by oral route prior to challenge with aerosolized 0.5% OVA. Bronchoconstriction tests were performed and respiratory parameters (i.e., tidal volume and respiratory rate) were measured. At the end of experiment, blood was collected from each animal to perform total and differential counts and serum was used for assay of IL-4, IL-6, and TNFalpha. Lung lavage fluid (BAL) was collected for estimation of cellular content and cytokine levels. Lung tissue histamine assays were performed using the homogenate of one lobe from each animal; a separate lobe and the trachea were subjected to histopathology to measure the degree of any airway inflammation. The results suggest that in OVA-sensitized control animals that did not receive either drug, tidal volume (V(t)) was decreased, respiration rate (f) was increased, and both the total and differential cell counts in blood and BAL fluid were increased significantly. MOEE-treatment of sensitized hosts resulted in improvement in all parameters except BAL TNFalpha and IL-4. Moreover, MOEE-treatment also showed protection against acetylcholine-induced broncho-constriction and airway inflammation which was confirmed by histological observations. The results of these studies confirm the traditional claim for the usefulness of this herb in the treatment of allergic disorders like asthma.
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20
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Abstract
Asthma has long been considered a condition in which psychological factors have a role. As in many illnesses, psychological variables may affect outcome in asthma via their effects on treatment adherence and symptom reporting. Emerging evidence suggests that the relation between asthma and psychological factors may be more complex than that, however. Central cognitive processes may influence not only the interpretation of asthma symptoms but also the manifestation of measurable changes in immune and physiologic markers of asthma. Furthermore, asthma and major depressive disorder share several risk factors and have similar patterns of dysregulation in key biologic systems, including the neuroendocrine stress response, cytokines, and neuropeptides. Despite the evidence that depression is common in people with asthma and exerts a negative impact on outcome, few treatment studies have examined whether improving symptoms of depression do, in fact, result in better control of asthma symptoms or improved quality of life in patients with asthma.
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Affiliation(s)
- Ryan J Van Lieshout
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON
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21
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Wang L, Pozzato V, Turato G, Madamanchi A, Murphy TM, Chitano P. Reduced spontaneous relaxation in immature guinea pig airway smooth muscle is associated with increased prostanoid release. Am J Physiol Lung Cell Mol Physiol 2008; 294:L964-73. [PMID: 18326825 DOI: 10.1152/ajplung.00401.2007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Airway smooth muscle (ASM) from infant guinea pigs has less spontaneous relaxation during stimulation than ASM from adults. Inhibition of cyclooxygenase (COX), which catalyzes the production of prostanoids, increases this relaxation in infant ASM and abolishes age differences, thus suggesting that prostanoids reduce relaxation in infant ASM. In this study, we investigated whether leukotrienes are also involved in reducing spontaneous relaxation; whether the two COX isoforms, COX-1 and COX-2, differentially regulate spontaneous relaxation; and whether prostanoid release is developmentally regulated in guinea pig ASM. In different age groups, we measured relaxation during and after electrical stimulation in tracheal strips as well as prostanoid release from tracheal segments. Relaxation was studied in the absence and in the presence of a lipoxygenase inhibitor, a cysteinyl leukotriene receptor-1 antagonist, a COX-1 inhibitor, or a COX-2 inhibitor. We found that inhibition of lipoxygenase or cysteinyl leukotriene receptor-1 antagonism did not increase spontaneous relaxation at any age, thus excluding a role for leukotrienes in this phenomenon. Inhibition of COX-2, but not COX-1, promoted spontaneous relaxation. The basal release of prostanoids was more abundant in tissue from infant animals and decreased significantly with age. Thromboxane B2 was the most abundant metabolite released at all ages. Electrical stimulation and epithelium removal did not affect the age difference in prostanoid release. We conclude that increased basal prostanoid release contributes to the reduced spontaneous relaxation in immature guinea pig ASM compared with older animals. By regulating ASM relaxation, prostanoids may play a role in the airway hyperresponsiveness at a young age.
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Affiliation(s)
- Lu Wang
- Division of Pediatric Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
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22
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Nakahata N. Thromboxane A2: physiology/pathophysiology, cellular signal transduction and pharmacology. Pharmacol Ther 2008; 118:18-35. [PMID: 18374420 DOI: 10.1016/j.pharmthera.2008.01.001] [Citation(s) in RCA: 298] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 01/02/2008] [Indexed: 12/22/2022]
Abstract
Thromboxane A(2) (TXA(2)), an unstable arachidonic acid metabolite, elicits diverse physiological/pathophysiological actions, including platelet aggregation and smooth muscle contraction. TXA(2) has been shown to be involved in allergies, modulation of acquired immunity, atherogenesis, neovascularization, and metastasis of cancer cells. The TXA(2) receptor (TP) communicates mainly with G(q) and G(13), resulting in phospholipase C activation and RhoGEF activation, respectively. In addition, TP couples with G(11), G(12), G(13), G(14), G(15), G(16), G(i), G(s) and G(h). TP is widely distributed in the body, and is expressed at high levels in thymus and spleen. The second extracellular loop of TP is an important ligand-binding site, and Asp(193) is a key amino acid. There are two alternatively spliced isoforms of TP, TPalpha and TPbeta, which differ only in their C-terminals. TPalpha and TPbeta communicate with different G proteins, and undergo hetero-dimerization, resulting in changes in intracellular traffic and receptor protein conformations. TP cross-talks with receptor tyrosine kinases, such as EGF receptor, to induce cell proliferation and differentiation. TP is glycosylated in the N-terminal region for recruitment to plasma membranes. Furthermore, TP conformation is changed by coupling to G proteins, showing several states of agonist binding. Finally, several drugs modify TP-mediated events; these include cyclooxygenase inhibitors, TXA(2) synthase inhibitors and TP antagonists. Some flavonoids of natural origin also have TP receptor antagonistic activity. Recent advances in TP research have clarified TXA(2)-mediated events in detail, and further study will supply more beneficial information about TXA(2) pathophysiology.
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Affiliation(s)
- Norimichi Nakahata
- Department of Cellular Signaling, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-0815, Japan
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23
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Abstract
Common G protein-coupled receptor (GPCR) gene variants that encode receptor proteins with a distinct sequence may alter drug efficacy without always resulting in a disease phenotype. GPCR genetic loci harbor numerous variants, such as DNA insertions or deletions and single-nucleotide polymorphisms that alter GPCR expression and function, thereby contributing to interindividual differences in disease susceptibility/progression and drug responses. In this chapter, these pharmacogenetic phenomena are reviewed with respect to a limited sampling of GPCR systems, including the beta(2)-adrenergic receptors, the cysteinyl leukotriene receptors, and the calcium-sensing receptor. In each example, the nature of the disruption to receptor function that results from each variant is discussed with respect to the regulation of gene expression, expression on cell surface (affected by receptor trafficking, dimerization, desensitization/downregulation), or perturbation of receptor function (by altering ligand binding, G protein coupling, and receptor constitutive activity). Despite the breadth of pharmacogenetic knowledge available, assessment for genetic variants is only occasionally applied to drug development projects involving pharmacogenomics or to optimizing the clinical use of GPCR drugs. The continued effort by the basic science of pharmacogenetics may draw the attention of drug discovery projects and clinicians alike to the utility of personalized pharmacogenomics as a means to optimize novel GPCR drug targets.
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Affiliation(s)
- Miles D Thompson
- Department of Laboratory Medicine and Pathobiology, Banting Institute, University of Toronto, Toronto, Ontario, Canada
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24
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Kim SH, Kim YK, Park HW, Jee YK, Kim SH, Bahn JW, Chang YS, Kim SH, Ye YM, Shin ES, Lee JE, Park HS, Min KU. Association between polymorphisms in prostanoid receptor genes and aspirin-intolerant asthma. Pharmacogenet Genomics 2007; 17:295-304. [PMID: 17496729 DOI: 10.1097/01.fpc.0000239977.61841.fe] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Genetic predisposition is linked to the pathogenesis of aspirin-intolerant asthma. Most candidate gene approaches have focused on leukotriene-related pathways, whereas there have been relatively few studies evaluating the effects of polymorphisms in prostanoid receptor genes on the development of aspirin-intolerant asthma. Therefore, we investigated the potential association between prostanoid receptor gene polymorphisms and the aspirin-intolerant asthma phenotype. METHODS We screened for genetic variations in the prostanoid receptor genes PTGER1, PTGER2, PTGER3, PTGER4, PTGDR, PTGIR, PTGFR, and TBXA2R using direct sequencing, and selected 32 tagging single nucleotide polymorphisms among the 77 polymorphisms with frequencies >0.02 based on linkage disequilibrium for genotyping. We compared the genotype distributions and allele frequencies of three participant groups (108 patients with aspirin-intolerant asthma, 93 patients with aspirin-tolerant asthma, and 140 normal controls). RESULTS Through association analyses studies of the 32 single nucleotide polymorphisms, the following single nucleotide polymorphisms were found to have significant associations with the aspirin-intolerant asthma phenotype: -616C>G (P=0.038) and -166G>A (P=0.023) in PTGER2; -1709T>A (P=0.043) in PTGER3; -1254A>G (P=0.018) in PTGER4; 1915T>C (P=0.015) in PTGIR; and -4684C>T (P=0.027), and 795T>C (P=0.032) in TBXA2R. In the haplotype analysis of each gene, the frequency of PTGIR ht3[G-G-C-C], which includes 1915T>C, differed significantly between the aspirin-intolerant asthma patients and aspirin-tolerant asthma patients (P=0.015). CONCLUSION These findings suggest that genetic polymorphisms in PTGER2, PTGER3, PTGER4, PTGIR, and TBXA2R play important roles in the pathogenesis of aspirin-intolerant asthma.
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Affiliation(s)
- Sang-Heon Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Korea
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25
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Thompson MD, Takasaki J, Capra V, Rovati GE, Siminovitch KA, Burnham WM, Hudson TJ, Bossé Y, Cole DEC. G-protein-coupled receptors and asthma endophenotypes: the cysteinyl leukotriene system in perspective. Mol Diagn Ther 2007; 10:353-66. [PMID: 17154652 DOI: 10.1007/bf03256212] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Genetic variation in specific G-protein coupled receptors (GPCRs) is associated with a spectrum of respiratory disease predispositions and drug response phenotypes. Although certain GPCR gene variants can be disease-causing through the expression of inactive, overactive, or constitutively active receptor proteins, many more GPCR gene variants confer risk for potentially deleterious endophenotypes. Endophenotypes are traits, such as bronchiole hyperactivity, atopy, and aspirin intolerant asthma, which have a strong genetic component and are risk factors for a variety of more complex outcomes that may include disease states. GPCR genes implicated in asthma endophenotypes include variants of the cysteinyl leukotriene receptors (CYSLTR1 and CYSLTR2), and prostaglandin D2 receptors (PTGDR and CRTH2), thromboxane A2 receptor (TBXA2R), beta2-adrenergic receptor (ADRB2), chemokine receptor 5 (CCR5), and the G protein-coupled receptor associated with asthma (GPRA). This review of the contribution of variability in these genes places the contribution of the cysteinyl leukotriene system to respiratory endophenotypes in perspective. The genetic variant(s) of receptors that are associated with endophenotypes are discussed in the context of the extent to which they contribute to a disease phenotype or altered drug efficacy.
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Affiliation(s)
- Miles D Thompson
- Department of Laboratory Medicine and Pathobiology, University of Toronto, and Department of Medical Genetics and Microbiology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
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26
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Yalcin M, Cavun S, Yilmaz MS, Savci V. Activation of the central cholinergic system mediates the reversal of hypotension by centrally administrated U-46619, a thromboxane A2 analog, in hemorrhaged rats. Brain Res 2006; 1118:43-51. [PMID: 16962568 DOI: 10.1016/j.brainres.2006.08.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 07/31/2006] [Accepted: 08/04/2006] [Indexed: 11/25/2022]
Abstract
In the present study, we investigated the role of the central cholinergic system in mediating the pressor effect of intracerebroventricularly administrated U-46619, a thromboxane A2 (TxA2) analog, in hemorrhaged hypotensive rats. Hemorrhage was performed by withdrawing a total volume of 2.1 ml of blood per 100 g body weight over a period of 10 min. Intracerebroventricular (i.c.v.) injection of U-46619 (0.5, 1, 2 micro g) produced a dose- and time-dependent increase in arterial pressure and reversed the hypotension of this condition. Hemorrhage caused small increases in extracellular hypothalamic acetylcholine and choline levels. Intracerebroventricular administration of U-46619 (1 micro g) further increased the levels of extracellular acetylcholine and choline by 57% and 41%, respectively. Pretreatment with SQ-29548 (8 mug; i.c.v.), a selective TxA2 receptor antagonist, completely abrogated the effects of subsequent injection of U-46619 (1 mug; i.c.v.) on arterial pressure and extracellular acetylcholine and choline levels. Pretreatment with mecamylamine (50 micro g; i.c.v.), a cholinergic nonselective nicotinic receptor antagonist, attenuated the pressor effect of U-46619 (1 micro g, i.c.v.) in hemorrhaged rats whereas pretreatment with atropine (10 micro g; i.c.v.), a cholinergic nonselective muscarinic receptor antagonist, had no effect. Interestingly, pretreatment of rats with methyllycaconitine (10 micro g; i.c.v.) or alpha-bungarotoxin (10 micro g; i.c.v.), selective antagonists of alpha-7 subtype nicotinic acetylcholine receptors (alpha7nAChRs), partially abolished the pressor effect of U-46619 (1 micro g; i.c.v.) in the hypotensive condition. Pretreatment with a combination of mecamylamine plus methyllycaconitine or mecamylamine plus alpha-bungarotoxin attenuated the reversal effect of U-46619, but only to the same extent as pretreatment with either antagonist alone. In conclusion, i.c.v. administration of U-46619 restores arterial pressure and increases posterior hypothalamic acetylcholine and choline levels by activating central TxA2 receptors in hemorrhaged hypotensive rats. The activation of central nicotinic cholinergic receptors, predominantly alpha7nAChRs, partially acts as a mediator in the pressor responses to i.c.v. injection of U-46619 under these conditions.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Acetylcholine/metabolism
- Animals
- Blood Pressure/drug effects
- Blood Pressure/physiology
- Bridged Bicyclo Compounds, Heterocyclic
- Cholinergic Fibers/drug effects
- Cholinergic Fibers/metabolism
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Extracellular Fluid/drug effects
- Extracellular Fluid/metabolism
- Fatty Acids, Unsaturated
- Hemorrhage/complications
- Hemorrhage/physiopathology
- Hydrazines/pharmacology
- Hypotension/drug therapy
- Hypotension/etiology
- Hypotension/physiopathology
- Hypothalamus, Posterior/drug effects
- Hypothalamus, Posterior/metabolism
- Injections, Intraventricular
- Male
- Neural Pathways/drug effects
- Neural Pathways/metabolism
- Nicotinic Antagonists/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Thromboxane A2/analogs & derivatives
- Time Factors
- Vasoconstrictor Agents/pharmacology
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- Murat Yalcin
- Uludag University Veterinary Faculty, Department of Physiology, 16059, Görükle, Bursa, Turkey
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27
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Erkin EF, Celik P, Kayikçioğlu O, Deveci HM, Sakar A. Effects of latanoprost and betaxolol on cardiovascular and respiratory status of newly diagnosed glaucoma patients. Ophthalmologica 2006; 220:332-7. [PMID: 16954712 DOI: 10.1159/000094625] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 12/23/2004] [Indexed: 11/19/2022]
Abstract
AIMS To investigate the cardiovascular and respiratory effects of topical latanoprost 0.005% and topical betaxolol 0.25% monotherapy in newly diagnosed glaucoma patients. METHODS Fortynewly diagnosed glaucoma patients were enrolled in this prospective, observer-masked, randomized, parallel study. Patients received either latanoprost 0.005% or betaxolol 0.25% for a duration of 3 months. Baseline evaluation included intraocular pressure (IOP) measurement and cardiorespiratory examinations including pulse rate, systolic and diastolic blood pressure measurements and spirometry. These measurements were repeated after 3 months. RESULTS Both latanoprost and betaxolol reduced IOP significantly (p = 0.001). After 3 months of therapy, the mean pulse rate, systolic and diastolic blood pressure values of the betaxolol group were reduced (p = 0.027, p = 0.07 and p = 0.016, respectively). No significant changes occurred in the cardiovascular measurements of the latanoprost group (p > 0.05). There were no significant changes in any of the spirometric measurements tested for both groups (p > 0.05). CONCLUSION Both latanoprost and betaxolol are safe concerning respiratory functions. Betaxolol may cause small changes in the cardiovascular system, suggesting that blood pressure and pulse rates should be checked before and in regular intervals after prescribing it for the elderly. Latanoprost seems to be a safe medication in view of absence of systemic cardiovascular and respiratory side effects.
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Affiliation(s)
- Esin F Erkin
- Department of Ophthalmology, Celal Bayar University School of Medicine, Manisa, Turkey
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28
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Rolin S, Masereel B, Dogné JM. Prostanoids as pharmacological targets in COPD and asthma. Eur J Pharmacol 2006; 533:89-100. [PMID: 16458293 DOI: 10.1016/j.ejphar.2005.12.058] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 12/13/2005] [Indexed: 11/22/2022]
Abstract
COPD (Chronic Obstructive Pulmonary Disease) and bronchial asthma are two severe lung diseases which represent a major problem of world public health. Leukotrienes and prostanoids play an important role in the pathogenesis of pulmonary diseases. Prostanoids: prostaglandins (PGs) and thromboxane A2 (TXA2), the cyclooxygenase metabolites of arachidonic acid are implicated in the inflammatory cascade that occurs in asthmatic airways. Recently, the roles played by isoprostanes or prostaglandin-like compounds nonenzymatically generated via peroxidation of membrane phospholipids by reactive oxygen species, in particular F2-isoprostanes, in pulmonary pathophysiology have been highlighted. This article aims to provide an overview of the role of prostanoids and isoprostanes in the pathogenesis of COPD and asthma and to discuss the pharmacological strategies developed in prevention and/or treatment of these pathologies.
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MESH Headings
- Animals
- Asthma/drug therapy
- Asthma/metabolism
- Benzoquinones/pharmacology
- Benzoquinones/therapeutic use
- Carbazoles/pharmacology
- Carbazoles/therapeutic use
- Enzyme Inhibitors/pharmacology
- Enzyme Inhibitors/therapeutic use
- F2-Isoprostanes/metabolism
- Heptanoic Acids/pharmacology
- Heptanoic Acids/therapeutic use
- Humans
- Methacrylates/pharmacology
- Methacrylates/therapeutic use
- Prostaglandin Antagonists/pharmacology
- Prostaglandin Antagonists/therapeutic use
- Prostaglandin D2/metabolism
- Pulmonary Disease, Chronic Obstructive/drug therapy
- Pulmonary Disease, Chronic Obstructive/metabolism
- Randomized Controlled Trials as Topic
- Receptors, Immunologic/antagonists & inhibitors
- Receptors, Immunologic/metabolism
- Receptors, Prostaglandin/antagonists & inhibitors
- Receptors, Prostaglandin/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Sulfonamides/pharmacology
- Sulfonamides/therapeutic use
- Thromboxane A2/metabolism
- Thromboxane-A Synthase/antagonists & inhibitors
- Thromboxane-A Synthase/metabolism
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Affiliation(s)
- Stéphanie Rolin
- Department of Pharmacy, University of Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium
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29
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Ankem MK, Jerde TJ, Wilkinson ER, Nakada SY. Third Prize:Prostaglandin E2-3 Receptor Is Involved in Ureteral Contractility in Obstruction. J Endourol 2005; 19:1088-91. [PMID: 16283845 DOI: 10.1089/end.2005.19.1088] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND AND PURPOSE We previously found that prostaglandin (PG) E2 contracts acutely obstructed ureters while relaxing normal ureters. This study investigated the procontractile effects of the PG EP3 receptor in PGE(2)-mediated contractility in obstructed and normal porcine ureters. MATERIALS AND METHODS We created unilateral ureteral obstruction laparoscopically using titanium clips in farm pigs; the contralateral ureters were dissected as sham controls. Ureters were harvested 48 hours post-obstruction, cut into 5-mm segments, and suspended in water-jacketed tissue baths in Krebs buffer. Tissues were equilibrated for 1 hour, and spontaneous contractile rates were recorded. After 2 hours of incubation in Krebs (controls) or pertussis toxin (G(alpha)i signaling-protein inhibitor [EP-3 blockade]) 500 ng/mL, a concentration- response curve (10(-9) M-10(-5) M) to PGE(2), PGF(2), sulprostone (EP 3 agonist), or 0.01% ethanol (vehicle) was created (N = 4). RESULTS In the normal ureters, PGE(2) relaxed both pertussis toxin-treated and control tissues. In obstructed segments, PGE(2) increased contractions by 60%; this was reversed by pertussis toxin to a 67% reduction in contractile rate. In both obstructed and contralateral segments, sulprostone induced contractility in the controls; this was attenuated by pertussis toxin. The PGF(2) produced a contractile effect in both the controls and the pertussis toxin-treated segments, demonstrating the selectivity of pertussis toxin for EP3 receptors. CONCLUSION Our data indicate that the EP3 receptor is involved in hypercontractility during ureteral obstruction. However, it may not be the sole factor behind the condition-dependent effect of PGE(2).
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Affiliation(s)
- Murali K Ankem
- Division of Urology, Department of Surgery, University of Wisconsin-Madison Medical School, Madison, Wisconsin 53792, USA
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30
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Kim SH, Choi JH, Park HS, Holloway JW, Lee SK, Park CS, Shin HD. Association of thromboxane A2 receptor gene polymorphism with the phenotype of acetyl salicylic acid-intolerant asthma. Clin Exp Allergy 2005; 35:585-90. [PMID: 15898979 DOI: 10.1111/j.1365-2222.2005.02220.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND OBJECTIVE The thromboxane A2 receptor (TBXA2R) is a receptor for a potent bronchoconstrictor, TBXA2 which is known to be related to bronchial asthma and myocardial infarction. TBXA2R antagonist and TBX synthase inhibitors have been found to be effective in the management of asthmatic patients. This study was aimed to evaluate whether genetic variants of TBXA2R may be related with development of acetyl salicylic acid (ASA)-intolerant asthma (AIA). METHODS TBXA2R gene polymorphisms (TBXA2R+795T>C, TBXA2R+924T>C) were determined using a single-base extension method in 93 AIA patients compared with 172 patients with ASA-tolerant asthma (ATA) and 118 normal controls (NCs) recruited from the Korean population. HLA DPB1*0301 genotype was performed using a direct sequencing method. RESULTS The rare C allele frequency of TBXA2R+795T>C was significantly higher in AIA than in ATA (P=0.03) and the TBXA2R+795T>C polymorphism was also associated with extent of percent fall in forced expiratory volume in 1 s (FEV1) after the inhalation of lysine-acetyl salicylic acid in AIA patients (P=0.009); AIA patients homozygous for the +795 C allele had a greater percent fall of FEV1 compared with individuals with TBXA2R+795 CT or TT genotypes. The frequency of patients carrying both the TBXA2R+795T>C rare allele and HLA DPB1(*)0301 was significantly higher in AIA patients (29.4%) than in ATA patients (7.3%) (P=0.008, odds ratio=5.3). CONCLUSION These results suggest that the polymorphism of TBXA2R+795T>C may increase bronchoconstrictive response to ASA, which could contribute to the development of the AIA phenotype.
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Affiliation(s)
- S-H Kim
- Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, Korea
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31
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Yalcin M, Cavun S, Yilmaz MS, Savci V. The involvement of central cholinergic system in the pressor effect of intracerebroventricularly injected U-46619, a thromboxane A2 analog, in conscious normotensive rats. Naunyn Schmiedebergs Arch Pharmacol 2005; 372:31-40. [PMID: 16133489 DOI: 10.1007/s00210-005-1087-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Accepted: 07/18/2005] [Indexed: 10/25/2022]
Abstract
The aim of this study was to determine the involvement of the central cholinergic system in the rise in blood pressure evoked by the thromboxane A2 (TxA2) analog, U-46619, given centrally. Intracerebroventricular (i.c.v.) injections of U-46619 (0.5, 1.0 and 2.0 microg) caused dose- and time-related increases in blood pressure and decreased heart rate in awake rats. U-46619 (1 microg; i.c.v.) also produced an approximately 65% increase in posterior hypothalamic extracellular acetylcholine and choline levels. Pretreatment with SQ-29548 (8 microg; i.c.v.), selective TxA2 receptor antagonist, completely inhibited both the cardiovascular responses and the increase in acetylcholine and choline levels to subsequent injection of U-46619 (1 microg; i.c.v.). Atropine (10 microg; i.c.v.), nonselective muscarinic receptor antagonist, pretreatment did not affect the cardiovascular responses observed after U-46619 (1 microg; i.c.v.). Pretreatment with the nonselective nicotinic receptor antagonist, mecamylamine (50 microg; i.c.v.) attenuated the pressor effect of U-46619 (1 microg; i.c.v.). Higher doses of mecamylamine (75 and 100 microg; i.c.v.) pretreatments did not change the magnitude of the blockade of pressor response to U-46619; however, they abolished the bradycardic effect of U-46619 dose-dependently. Interestingly, pretreatment of rats with methyllycaconitine (10 microg; i.c.v.) or alpha-bungarotoxin (10 microg; i.c.v.), selective antagonists of alpha7 subtype of nicotinic acetylcholine receptors (alpha7nAChRs), partially abolished the pressor response to i.c.v. injection of U-46619 (1 microg). Similar to the mecamylamine data, the use of higher doses of methyllycaconitine (25 and 50 microg; i.c.v.) produced the same magnitude of blockade that was observed after the 10 microg methyllycaconitine pretreatment, but it completely abolished the bradycardic effect of U-46619 (1 microg; i.c.v.) at the dose of 25 microg. The present results show that central administration of U-46619 produces pressor and bradycardic effect and increase in hypothalamic acetylcholine and choline levels by activating central TxA2 receptors. The activation of central nicotinic receptors, predominantly alpha7nAChRs, partially mediates the cardiovascular responses to i.c.v. injection of U-46619.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/administration & dosage
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Acetylcholine/metabolism
- Aconitine/administration & dosage
- Aconitine/analogs & derivatives
- Animals
- Blood Pressure/drug effects
- Bridged Bicyclo Compounds, Heterocyclic
- Bungarotoxins/administration & dosage
- Central Nervous System/drug effects
- Central Nervous System/metabolism
- Choline/metabolism
- Fatty Acids, Unsaturated
- Heart Rate/drug effects
- Hydrazines/administration & dosage
- Hypothalamus, Posterior/drug effects
- Hypothalamus, Posterior/metabolism
- Injections, Intraventricular
- Male
- Mecamylamine/administration & dosage
- Nicotinic Antagonists/administration & dosage
- Rats
- Rats, Sprague-Dawley
- Receptors, Nicotinic/drug effects
- Receptors, Thromboxane A2, Prostaglandin H2/antagonists & inhibitors
- Time Factors
- Vasoconstrictor Agents/administration & dosage
- Vasoconstrictor Agents/pharmacology
- alpha7 Nicotinic Acetylcholine Receptor
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Affiliation(s)
- Murat Yalcin
- Department of Physiology, Uludag University Veterinary Faculty, 16059, Gorukle, Bursa, Turkey
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32
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Hong SJ, Lee SY, Kim HB, Kim JH, Kim BS, Choi SO, Lee SG, Shin ES, Hong TJ. IL-5 and thromboxane A2 receptor gene polymorphisms are associated with decreased pulmonary function in Korean children with atopic asthma. J Allergy Clin Immunol 2005; 115:758-63. [PMID: 15805995 DOI: 10.1016/j.jaci.2004.10.047] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Asthmatic airways undergo chronic inflammatory cell infiltration by T cells and eosinophils, which results in sustained airway hyperresponsiveness. IL-5 is important for eosinophil-induced airway inflammation and airway hyperresponsiveness. Thromboxane A2 and its receptor, TBXA2R, are involved in constriction of respiratory smooth muscles and may play a role in thickening and remodeling of airways, which contributes to the severity of asthma. The relationship between IL-5 and TBXA2R gene polymorphisms and pulmonary function in children with asthma has rarely been examined. OBJECTIVE To determine whether IL-5 (T-746C) and TBXA2R (T924C) gene polymorphisms are associated with asthma phenotype and pulmonary function in Korean children with atopic and nonatopic asthma. METHODS We conducted an association study between known polymorphisms of IL-5 (T-746C) and TBXA2R (T924C) and asthma phenotype and the parameters of atopy and pulmonary function in atopic and nonatopic Korean children with asthma. The subjects were 240 atopic children with asthma, 70 nonatopic children with asthma, and 106 nonatopic healthy children. Asthma phenotypes and bronchial responsiveness to methacholine were determined by a physician. IL-5 and TBXA2R gene polymorphisms were determined by genotyping by using PCR-RFLP assays. RESULTS The genotype frequencies of IL-5 and TBXA2R polymorphisms did not differ between healthy controls and atopic or nonatopic children with asthma. A significant association was observed between the IL-5 polymorphism and forced expiratory flow at 25% to 75% of forced vital capacity (FEF 25-75% ; %; P = .002), and between the TBXA2R polymorphism and FEV 1 (%; P = .035) and FEF 25-75% (%; P = .042) in children with atopic asthma, whereas no such association between the polymorphisms and lung function was observed in nonatopic or control children. In atopic children with asthma, we identified a significant gene-gene interaction in that the combination of the IL-5 (T-746C) and TBXA2R (T924C) mutant alleles was shown to be associated with reduced pulmonary function as determined by FEF 25-75% (%) measurement. CONCLUSION The current study indicates that IL-5 (T-746C) and TBXA2R (T924C) polymorphisms alone are associated with spirometric markers of asthma severity, whereas they are not associated with presence of asthma per se. In addition, the data suggest that an interaction between IL-5 and TBXA2R genes may contribute to the severity of asthma, especially atopic asthma. These results suggest that IL-5 and TBXA2R genes may be disease-modifying genes in Korean children with atopic asthma.
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Affiliation(s)
- Soo-Jong Hong
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul, Korea
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33
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Hata AN, Breyer RM. Pharmacology and signaling of prostaglandin receptors: multiple roles in inflammation and immune modulation. Pharmacol Ther 2005; 103:147-66. [PMID: 15369681 DOI: 10.1016/j.pharmthera.2004.06.003] [Citation(s) in RCA: 599] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Prostaglandins are lipid-derived autacoids that modulate many physiological systems including the CNS, cardiovascular, gastrointestinal, genitourinary, endocrine, respiratory, and immune systems. In addition, prostaglandins have been implicated in a broad array of diseases including cancer, inflammation, cardiovascular disease, and hypertension. Prostaglandins exert their effects by activating rhodopsin-like seven transmembrane spanning G protein-coupled receptors (GPCRs). The prostanoid receptor subfamily is comprised of eight members (DP, EP1-4, FP, IP, and TP), and recently, a ninth prostaglandin receptor was identified-the chemoattractant receptor homologous molecule expressed on Th2 cells (CRTH2). The precise roles prostaglandin receptors play in physiologic and pathologic settings are determined by multiple factors including cellular context, receptor expression profile, ligand affinity, and differential coupling to signal transduction pathways. This complexity is highlighted by the diverse and often opposing effects of prostaglandins within the immune system. In certain settings, prostaglandins function as pro-inflammatory mediators, but in others, they appear to have anti-inflammatory properties. In this review, we will discuss the pharmacology and signaling of the nine known prostaglandin GPCRs and highlight the specific roles that these receptors play in inflammation and immune modulation.
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MESH Headings
- Humans
- Inflammation/metabolism
- Phylogeny
- Prostaglandins/physiology
- Receptors, Epoprostenol/genetics
- Receptors, Epoprostenol/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Prostaglandin/genetics
- Receptors, Prostaglandin/metabolism
- Receptors, Prostaglandin E/genetics
- Receptors, Prostaglandin E/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/genetics
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
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Affiliation(s)
- Aaron N Hata
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
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34
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Böhm E, Sturm GJ, Weiglhofer I, Sandig H, Shichijo M, McNamee A, Pease JE, Kollroser M, Peskar BA, Heinemann A. 11-Dehydro-thromboxane B2, a stable thromboxane metabolite, is a full agonist of chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) in human eosinophils and basophils. J Biol Chem 2003; 279:7663-70. [PMID: 14668348 DOI: 10.1074/jbc.m310270200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thromboxane (TX) A(2), a cyclooxygenase-derived mediator involved in allergic responses, is rapidly converted in vivo to a stable metabolite, 11-dehydro-TXB(2), which is considered to be biologically inactive. In this study, we found that 11-dehydro-TXB(2), but not the TXA(2) analogue U46,619 or TXB(2), activated eosinophils and basophils, as assayed by flow cytometric shape change. 11-Dehydro-TXB(2) was also chemotactic for eosinophils but did not induce, nor inhibit, platelet aggregation. Chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) is an important chemoattractant receptor expressed by eosinophils, basophils, and TH2 lymphocytes, and prostaglandin (PG)D(2) has been shown to be its principal ligand. 11-Dehydro-TXB(2) induced calcium flux mainly from intracellular stores in eosinophils, and this response was desensitized after stimulation with PGD(2) but not other eosinophil chemoattractants. Shape change responses of eosinophils and basophils to 11-dehydro-TXB(2) were inhibited by the thromboxane (TP)/CRTH2 receptor antagonist ramatroban, but not the selective TP antagonist SQ29,548, and were insensitive to pertussis toxin. The phospholipase C inhibitor U73,122 attenuated both 11-dehydro-TXB(2)- and PGD(2)-induced shape change. 11-Dehydro-TXB(2) also induced the chemotaxis of BaF/3 cells transfected with hCRTH2 but not naive BaF/3 cells. At a threshold concentration, 11-dehydro-TXB(2) had no antagonistic effect on CRTH2-mediated responses as induced by PGD2. These data show that 11-dehydro-TXB(2) is a full agonist of the CRTH2 receptor and hence might cause CRTH2 activation in cellular contexts where PGD-synthase is not present. Given its production in the allergic lung, antagonism of the 11-dehydro-TXB(2)/CRTH2axis may be of therapeutic relevance.
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Affiliation(s)
- Eva Böhm
- Department of Experimental and Clinical Pharmacology, Medical University Graz, A-8010 Graz, Austria
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35
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Yaekashiwa M, Wang LH. Nrf2 regulates thromboxane synthase gene expression in human lung cells. DNA Cell Biol 2003; 22:479-87. [PMID: 14565864 DOI: 10.1089/10445490360708883] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Thromboxane A(2) synthase (TXAS) converts prostaglandin H(2) to thromboxane A(2), a potent inducer of vaso-constriction and platelet aggregation. TXAS expression level is cell type preferential; high in hematopoietic cells and low in nonhematopoietic cells. We previously showed that p45 NF-E2 activated the TXAS promoter in hematopoietic cells via binding to the nucleotides -86/-77 from the transcriptional start site [Yaekashiwa and Wang (2002) J. Biol. Chem. 277, 22497-22508]. We reported here that, by transient transfection analysis, this region was also critical for TXAS trans-activation in the A549 and WI-38 lung cells. Mutation of the NF-E2 site greatly reduced TXAS promoter activity in these two types of cells. Using stably transfected A549 cells, we showed that an NF-E2 mutation retained only 0.25% of the wild-type promoter activity. Ecotopic expression of NF-E2 related factors showed that Nrf2, but not Nrf1, Nrf3, or Bach1, activated TXAS promoter in a dose-dependent manner. Furthermore, chromatin immunoprecipitation assay using the stably transfected A549 cells demonstrated that Nrf2 bound the TXAS NF-E2 site in vivo. TXAS gene thus utilizes the same cis-acting element but different trans-acting factors to confer cell-preferential expression. We also showed that forced expression of p300 upregulated TXAS gene in a dose-dependent manner. Mutation of NF-E2 site, but not TATA or initiator site, abolished the p300-mediated activation of TXAS gene.
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Affiliation(s)
- Masahiro Yaekashiwa
- Division of Hematology, Department of Internal Medicine, University of Texas-Houston, Houston, Texas 77030, USA
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36
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Saffak T, Schäfer S, Haas C, Nüsing RM. Regulation of the human thromboxane A2 receptor gene in human megakaryoblastic MEG-01 cells. Prostaglandins Leukot Essent Fatty Acids 2003; 69:299-306. [PMID: 14580363 DOI: 10.1016/s0952-3278(03)00112-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Thromboxane A(2) (TXA(2)) is an important mediator for platelet aggregation and blood vessel constriction. TXA(2) receptor (TP receptor) is expressed in different cell types including smooth muscle cells, endothelial cells and platelets. Expression level of TP receptor may modulate the action of TXA(2) on target cells. In megakaryoblastic MEG-01 cells, a cell line representing a model for platelet precursor cells, addition of phorbolester 12-O-tetradecanoylphorbol-13-acetate (TPA) caused an increase in transcriptional activity of TP receptor gene promoter. Within 20 h a rise in expression of TP receptor mRNA and protein was observed. The effect of TPA was concentration-dependent and was blocked by specific inhibitors of protein kinase C. Flow cytometry analysis indicated that the increase in TP receptor expression appeared to be one of the earliest events in the course of TPA-induced maturation of MEG-01 cells. Stimulation of the protein kinase A pathway by incubation with forskolin or IBMX caused a decrease in transcriptional activity. Promoter deletion experiments indicated that the responsive elements for protein kinase A and C are located upstream and downstream, respectively, of -700 bp of the TP receptor gene. These experiments indicate that the expression of the human thromboxane receptor is differently regulated in platelet precursor cells by the protein kinase A and C pathway.
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Affiliation(s)
- T Saffak
- Department of Pediatrics, Faculty of Medicine, Philipp's University, Deutschhausstrasse 12, 35037 Marburg, Germany
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37
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Shin HD, Park BL, Jung JH, Wang HJ, Park HS, Choi BW, Hong SJ, Lee YM, Kim YH, Park CS. Association of thromboxane A2 receptor (TBXA2R) with atopy and asthma. J Allergy Clin Immunol 2003; 112:454-7. [PMID: 12897758 DOI: 10.1067/mai.2003.1641] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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38
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Michaux C, Dogné JM, Rolin S, Masereel B, Wouters J, Durant F. A pharmacophore model for sulphonyl-urea (-cyanoguanidine) compounds with dual action, thromboxane receptor antagonists and thromboxane synthase inhibitors. Eur J Med Chem 2003; 38:703-10. [PMID: 12932901 DOI: 10.1016/s0223-5234(03)00076-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A 3D pharmacophore model was developed for original sulphonyl-urea (-cyanoguanidine) compounds and known molecules which behave both as thromboxane receptor antagonists and as thromboxane synthase inhibitors. Five recognition sites appear to be essential for this dual activity: two hydrogen bond acceptors, an anionic site, a hydrophobic group and an aromatic ring. Such a model could be used to design new leads possessing the same pharmacological profile and to improve the activity of our compounds.
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Affiliation(s)
- Catherine Michaux
- Laboratoire Chimie Moléculaire Structurale, Facultés Universitaires N.-D. de la Paix, 61, rue de Bruxelles, B-5000, Namur, Belgium.
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39
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Fukuoka T, Miyake S, Umino T, Inase N, Tojo N, Yoshizawa Y. The effect of seratrodast on eosinophil cationic protein and symptoms in asthmatics. J Asthma 2003; 40:257-64. [PMID: 12807169 DOI: 10.1081/jas-120018322] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Thromboxane A2 (TXA2), an arachidonate derivative, is a potent bronchoconstrictor; therefore, blocking TXA2 should attenuate airway narrowing. Seratrodast, a TXA2 receptor antagonist, is expected to be a potent antiasthmatic. It was reported that seratrodast reduced bronchial hyperresponsiveness. However, it is controversial whether it reduces airway inflammation. We studied some additional effects of oral seratrodast to inhaled corticosteroids on 10 adult asthmatics in an open-label, crossover design study. Eosinophil cationic protein (ECP) levels in serum and sputum, peak expiratory flow rate (PEF), clinical symptoms, and airway responsiveness were evaluated. Clinical symptom scores were improved by administration of seratrodast (p < 0.05). The addition of seratrodast to asthmatic patients significantly improved mean PEF (p < 0.05). In addition, withdrawal of seratrodast resulted in deterioration of PEF. Airway hyperresponsiveness to acetylcholine measured by Astograph was improved by administration of seratrodast (p < 0.01), and returned to the level of "run-in period" after withdrawal. Administration of seratrodast decreased the concentration of ECP in sputum significantly (p < 0.05), and sputum ECP significantly increased again after withdrawal of (p < 0.05). These results suggest that seratrodast improves clinical symptoms andairway hyperresponsiveness by reducing airway inflammation. Seratrodast may be useful as an anti-inflammatory agent and beneficial when added to inhaled corticosteroids in the treatment of bronchial asthma.
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Affiliation(s)
- Toshihiko Fukuoka
- The Pulmonary Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
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40
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Takiguchi Y, Okamura HO, Kitamura K. Expression of cyclooxygenase-1 and -2 is limited to the nasal glands in the guinea pig nasal cavity. Acta Otolaryngol 2003; 123:302-5. [PMID: 12701763 DOI: 10.1080/00016480310000476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To clarify the localization of cyclooxygenase (COX)-1 and -2 in the nasal cavity of guinea pigs and ascertain their physiological roles. MATERIAL AND METHODS The distribution of the enzymes was investigated using immunohistochemistry. RESULTS Immunoreactivities for COX-1 and -2 were limited to the nasal glands, and no expression was noted in the surrounding vascular endothelial cells, olfactory glands, respiratory epithelium, olfactory epithelium, submucosal tissue or nerves. To confirm the specificity of the reaction, the kidneys of the same animals were prepared as positive controls. The results demonstrated localization of COX-1 and -2 in uriniferous tubules. CONCLUSION Our findings suggest that COX is involved in the secretion of nasal discharge from the nasal glands and that prostaglandins in the nasal discharge are probably secreted directly from the nasal glands.
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Affiliation(s)
- Yoshitaka Takiguchi
- Department of Otolaryngology, Tokyo Medical and Dental University, Graduate School, Tokyo, Japan.
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41
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Khan AM, Lally KP, Larsen GL, Colasurdo GN. Enhanced release of thromboxane A(2) after exposure of human airway epithelial cells to meconium. Pediatr Pulmonol 2002; 33:111-6. [PMID: 11802247 DOI: 10.1002/ppul.10058] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Meconium aspiration syndrome (MAS) is a cause of significant morbidity and mortality in the perinatal period. Despite the clinical relevance of MAS, its pathogenesis is poorly understood. Epithelial cell-derived prostanoids are involved in the regulation of several cellular functions within the lung, including the control of tone and reactivity of airway and vascular smooth muscle. In this study, we evaluated whether exposure to meconium affects the metabolic function of human airway epithelial cells. Monolayers of A549 cells, a transformed human epithelial cell line, were incubated with various concentrations of meconium. Control cells were incubated with serum-free medium in a similar manner. The supernatant fluid was removed at various time points and assayed for thromboxane A(2) (TXA(2)) production. The latter was accomplished by measuring its immediate and stable metabolite thromboxane B(2), using an enzyme-linked immunosorbent assay (ELISA). In selected experiments, the modulatory effects of indomethacin (10(-6) M), dexamethasone (10(-6) M), and L-nitroarginine methyl ester (L-NAME, 10(-6) M) on TXA(2) production were evaluated. Results were expressed in terms of pg/mg protein (mean +/- SE). We found that exposure to meconium produced a significant release of TXA(2) from A549 cells. Indomethacin, dexamethasone, and in part, L-NAME inhibited meconium-induced release of TXA(2). Our findings demonstrate that meconium enhances the production of thromboxanes from A549 cells, suggesting that airway epithelial cells and their metabolic products may play an important role in the pathogenesis of MAS.
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Affiliation(s)
- Amir M Khan
- Department of Pediatrics, University of Texas-Houston Medical School, Houston, Texas 77030, USA
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Dogné JM, de Leval X, Benoit P, Delarge J, Masereel B. Thromboxane A2 inhibition: therapeutic potential in bronchial asthma. AMERICAN JOURNAL OF RESPIRATORY MEDICINE : DRUGS, DEVICES, AND OTHER INTERVENTIONS 2002; 1:11-7. [PMID: 14720071 DOI: 10.1007/bf03257158] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Bronchial asthma is a disease defined by reversible airway obstruction, bronchial hyperresponsiveness and inflammation. In addition to histamine and acetylcholine, recent studies have emphasized the role of arachidonic acid metabolites (leukotrienes, prostaglandins and thromboxane A(2)) in the pathogenesis of asthma. Among these mediators, thromboxane A(2) (TXA(2)) has attracted attention as an important mediator in the pathophysiology of asthma because of its potent bronchoconstrictive activity. Thromboxane A(2) is believed to be involved not only in late asthmatic responses but also in bronchial hyperresponsiveness, a typical feature of asthma. Strategies for inhibition of TXA(2) include TXA(2) receptor antagonism and thromboxane synthase inhibition. Results of double-blind, placebo-controlled clinical trials have proven the efficacies of the thromboxane receptor antagonist seratrodast and the thromboxane synthase inhibitor ozagrel in the treatment of patients with asthma. Seratrodast and ozagrel are available in Japan for the treatment of asthma. Ramatroban, another thromboxane receptor antagonist, is currently under phase III clinical evaluation in Europe and Japan for the treatment of asthma. The pharmacological profiles of the thromboxane modulators may be improved by combination with leukotriene D(4) receptor antagonists. A multi-pathway inhibitory agent such as YM 158, which is a novel orally active dual antagonist for leukotriene D(4) and thromboxane A(2 )receptors, may have potent therapeutic effects in the treatment of bronchial asthma. Large scale clinical trials are necessary to further define the role of thromboxane modulators in the treatment of patients with asthma.
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Affiliation(s)
- Jean-Michel Dogné
- Department of Medicinal Chemistry, University of Liège, Avenue de l'Hôpital 1, B36, B-4000 Liège, Belgium
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Abstract
UNLABELLED 1. We characterized the responses of murine airways and pulmonary vessels to a variety of endogenous mediators in the isolated perfused and ventilated mouse lung (IPL) and compared them with those in precision-cut lung slices. 2. Airways: The EC50 (microM) for contractions of airways in IPL/slices was methacholine (Mch), 6.1/1.5>serotonin, 0.7/2.0>U46619 (TP-receptor agonist), 0.1/0.06>endothelin-1, 0.1/0.05. In the IPL, maximum increase in airway resistance (RL) was 0.6, 0.4, 0.8 and 11 cmH2O s ml(-1), respectively. Adenosine (< or =1 mM), bombesin (< or =100 microM), histamine (< or =10 mM), LTC4 (< or =1 microM), PAF (0.25 microM) and substance P (< or =100 microM) had only weak effects (<5% of Mch) on RL. 3. Vessels: The EC50 (microM) for vasoconstriction in the IPL was LTC4, 0.06>U46619, 0.05<endothelin-1, 0.02. The maximum increase in pulmonary artery pressure (PAP) was 11, 41 and 48 cmH2O, respectively. At 250 nM, the activity of PAF was comparable to that of LTC4. At 100 microM only, substance P caused a largely variable increase in PAP. Serotonin, adenosine, bombesin, histamine and Mch had no or only very small effects on PAP. 4. Hyperresponsiveness: In both the IPL and slices, U46619 in subthreshold concentrations (10 nM) reduced the EC50 to 0.6 microM. In the IPL, U46619 raised the maximum airway response to Mch 5 fold and the maximum PAF-induced vasoconstriction 4 fold. 5. CONCLUSION Murine precision-cut lung slices maintain important characteristics of the whole organ. The maximum reagibility of murine airways to endogenous mediators is serotonin<Mch<U46619<ET-1. The reagibility of the murine pulmonary vasculature is serotonin<LTC4 approximately = to PAF<U46619<ET-1. The airway and vessel hyperreactivity induced by U46619 raises the possibility that thromboxane contributes directly to airway hyperresponsiveness in various experimental and clinical settings.
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Affiliation(s)
- Heinz-Dieter Held
- Division of Pulmonary Pharmacology, Research Centre Borstel, Parkallee 22, 23845 Borstel, Germany
| | - Christian Martin
- Division of Pulmonary Pharmacology, Research Centre Borstel, Parkallee 22, 23845 Borstel, Germany
| | - Stefan Uhlig
- Division of Pulmonary Pharmacology, Research Centre Borstel, Parkallee 22, 23845 Borstel, Germany
- Author for correspondence:
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Chambers RJ, Marfat A. Leukotriene antagonists: patent highlights 1996 - 1998. Expert Opin Ther Pat 1999. [DOI: 10.1517/13543776.9.1.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Thomas DW, Mannon RB, Mannon PJ, Latour A, Oliver JA, Hoffman M, Smithies O, Koller BH, Coffman TM. Coagulation defects and altered hemodynamic responses in mice lacking receptors for thromboxane A2. J Clin Invest 1998; 102:1994-2001. [PMID: 9835625 PMCID: PMC509152 DOI: 10.1172/jci5116] [Citation(s) in RCA: 198] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Thromboxane A2 (TXA2) is a labile metabolite of arachidonic acid that has potent biological effects. Its actions are mediated by G protein-coupled thromboxane-prostanoid (TP) receptors. TP receptors have been implicated in the pathogenesis of cardiovascular diseases. To investigate the physiological functions of TP receptors, we generated TP receptor-deficient mice by gene targeting. Tp-/- animals reproduce and survive in expected numbers, and their major organ systems are normal. Thromboxane agonist binding cannot be detected in tissues from Tp-/- mice. Bleeding times are prolonged in Tp-/- mice and their platelets do not aggregate after exposure to TXA2 agonists. Aggregation responses after collagen stimulation are also delayed, although ADP-stimulated aggregation is normal. Infusion of the TP receptor agonist U-46619 causes transient increases in blood pressure followed by cardiovascular collapse in wild-type mice, but U-46619 caused no hemodynamic effect in Tp-/- mice. Tp-/- mice are also resistant to arachidonic acid-induced shock, although arachidonic acid signifi-cantly reduced blood pressure in Tp-/- mice. In summary, Tp-/- mice have a mild bleeding disorder and altered vascular responses to TXA2 and arachidonic acid. Our studies suggest that most of the recognized functions of TXA2 are mediated by the single known Tp gene locus.
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Affiliation(s)
- D W Thomas
- Department of Medicine, Duke University and Durham Veterans Affairs Medical Centers, Durham, North Carolina 27705, USA
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Thomas DW, Coffman TM. A genetic approach for studying the role of thromboxane A2 in the kidney. KIDNEY INTERNATIONAL. SUPPLEMENT 1998; 67:S84-7. [PMID: 9736260 DOI: 10.1046/j.1523-1755.1998.06717.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Thromboxane A2 (TxA2) has been implicated in a number of processes in normal kidney physiology and as a mechanism for injury in renal disease. TxA2 is a biologically active derivative of arachidonic acid and has potent vasoconstrictive and platelet-activation functions. Its actions are mediated by binding to specific G-protein-associated receptors designated TP receptors. There are at least two isoforms of the human TP receptor, and pharmacological evidence suggests TP receptor heterogeneity in other species. TP receptors are located in the renal cortex, and there may also be TxA2 binding sites in the medulla. TP receptors are involved in some normal functions of the kidney, and there is considerable evidence that TP receptors may mediate renal damage in disease states. To assess directly the role of the TxA2 in normal kidney function and in murine models of human disease, we have used gene targeting to eliminate expression of the TP receptor in mice.
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Affiliation(s)
- D W Thomas
- Duke University and Durham Veterans Affairs Medical Centers, North Carolina, USA
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