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Schmidt M, Dekker FJ, Maarsingh H. Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions. Pharmacol Rev 2013; 65:670-709. [PMID: 23447132 DOI: 10.1124/pr.110.003707] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and gene transcription, is reflected by the award of five Nobel prizes. The discovery of Epac (exchange protein directly activated by cAMP) has ignited a new surge of cAMP-related research and has depicted novel cAMP properties independent of protein kinase A and cyclic nucleotide-gated channels. The multidomain architecture of Epac determines its activity state and allows cell-type specific protein-protein and protein-lipid interactions that control fine-tuning of pivotal biologic responses through the "old" second messenger cAMP. Compartmentalization of cAMP in space and time, maintained by A-kinase anchoring proteins, phosphodiesterases, and β-arrestins, contributes to the Epac signalosome of small GTPases, phospholipases, mitogen- and lipid-activated kinases, and transcription factors. These novel cAMP sensors seem to implement certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Agonists and antagonists selective for Epac are developed and will support further studies on the biologic net outcome of the activation of Epac. This will increase our current knowledge on the pathophysiology of devastating diseases, such as diabetes, cognitive impairment, renal and heart failure, (pulmonary) hypertension, asthma, and chronic obstructive pulmonary disease. Further insights into the cAMP dynamics executed by the Epac signalosome will help to optimize the pharmacological treatment of these diseases.
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Affiliation(s)
- Martina Schmidt
- Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands.
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Walker JKL, Kraft M, Fisher JT. Assessment of murine lung mechanics outcome measures: alignment with those made in asthmatics. Front Physiol 2013; 3:491. [PMID: 23408785 PMCID: PMC3569663 DOI: 10.3389/fphys.2012.00491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 12/17/2012] [Indexed: 01/13/2023] Open
Abstract
Although asthma is characterized as an inflammatory disease, recent reports highlight the importance of pulmonary physiology outcome measures to the clinical assessment of asthma control and risk of asthma exacerbation. Murine models of allergic inflammatory airway disease have been widely used to gain mechanistic insight into the pathogenesis of asthma; however, several aspects of murine models could benefit from improvement. This review focuses on aligning lung mechanics measures made in mice with those made in humans, with an eye toward improving the translational utility of these measures. A brief description of techniques available to measure murine lung mechanics is provided along with a methodological consideration of their utilization. How murine lung mechanics outcome measures relate to pulmonary physiology measures conducted in humans is discussed and we recommend that, like human studies, outcome measures be standardized for murine models of asthma.
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Affiliation(s)
- Julia K L Walker
- Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center Durham, NC, USA
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Billington CK, Ojo OO, Penn RB, Ito S. cAMP regulation of airway smooth muscle function. Pulm Pharmacol Ther 2013; 26:112-20. [PMID: 22634112 PMCID: PMC3574867 DOI: 10.1016/j.pupt.2012.05.007] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 05/14/2012] [Accepted: 05/17/2012] [Indexed: 12/11/2022]
Abstract
Agonists activating β(2)-adrenoceptors (β(2)ARs) on airway smooth muscle (ASM) are the drug of choice for rescue from acute bronchoconstriction in patients with both asthma and chronic obstructive pulmonary disease (COPD). Moreover, the use of long-acting β-agonists combined with inhaled corticosteroids constitutes an important maintenance therapy for these diseases. β-Agonists are effective bronchodilators due primarily to their ability to antagonize ASM contraction. The presumed cellular mechanism of action involves the generation of intracellular cAMP, which in turn can activate the effector molecules cAMP-dependent protein kinase (PKA) and Epac. Other agents such as prostaglandin E(2) and phosphodiesterase inhibitors that also increase intracellular cAMP levels in ASM, can also antagonize ASM contraction, and inhibit other ASM functions including proliferation and migration. Therefore, β(2)ARs and cAMP are key players in combating the pathophysiology of airway narrowing and remodeling. However, limitations of β-agonist therapy due to drug tachyphylaxis related to β(2)AR desensitization, and recent findings regarding the manner in which β(2)ARs and cAMP signal, have raised new and interesting questions about these well-studied molecules. In this review we discuss current concepts regarding β(2)ARs and cAMP in the regulation of ASM cell functions and their therapeutic roles in asthma and COPD.
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Affiliation(s)
- Charlotte K Billington
- Division of Therapeutics and Molecular Medicine, The University of Nottingham, Nottingham NG7 2UH, UK.
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Kim V, Criner GJ. Chronic bronchitis and chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2013; 187:228-37. [PMID: 23204254 PMCID: PMC4951627 DOI: 10.1164/rccm.201210-1843ci] [Citation(s) in RCA: 286] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Accepted: 11/16/2012] [Indexed: 11/16/2022] Open
Abstract
Chronic bronchitis (CB) is a common but variable phenomenon in chronic obstructive pulmonary disease (COPD). It has numerous clinical consequences, including an accelerated decline in lung function, greater risk of the development of airflow obstruction in smokers, a predisposition to lower respiratory tract infection, higher exacerbation frequency, and worse overall mortality. CB is caused by overproduction and hypersecretion of mucus by goblet cells, which leads to worsening airflow obstruction by luminal obstruction of small airways, epithelial remodeling, and alteration of airway surface tension predisposing to collapse. Despite its clinical sequelae, little is known about the pathophysiology of CB and goblet cell hyperplasia in COPD, and treatment options are limited. In addition, it is becoming increasingly apparent that in the classic COPD spectrum, with emphysema on one end and CB on the other, most patients lie somewhere in the middle. It is known now that many patients with severe emphysema can develop CB, and small airway pathology has been linked to worse clinical outcomes, such as increased mortality and lesser improvement in lung function after lung volume reduction surgery. However, in recent years, a greater understanding of the importance of CB as a phenotype to identify patients with a beneficial response to therapy has been described. Herein we review the epidemiology of CB, the evidence behind its clinical consequences, the current understanding of the pathophysiology of goblet cell hyperplasia in COPD, and current therapies for CB.
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Affiliation(s)
- Victor Kim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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55
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Decramer ML, Hanania NA, Lötvall JO, Yawn BP. The safety of long-acting β2-agonists in the treatment of stable chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis 2013; 8:53-64. [PMID: 23378756 PMCID: PMC3558319 DOI: 10.2147/copd.s39018] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Inhaled long-acting bronchodilators are the mainstay of pharmacotherapy for chronic obstructive pulmonary disease (COPD). Both the twice-daily long-acting β(2)-adrenoceptor agonists (LABAs) salmeterol and formoterol and the once-daily LABA indacaterol are indicated for use in COPD. This review examines current evidence for the safety of LABAs in COPD, focusing on their effect on exacerbations and deaths. METHODS We searched PubMed for placebo-controlled studies evaluating long-term (≥24 weeks) use of formoterol, salmeterol, or indacaterol in patients with stable COPD, published between January 1990 and September 2012. We summarized data relating to exacerbations and adverse events, particularly events related to COPD. RESULTS From 20 studies examined (8774 LABA-treated patients), there was no evidence of an association between LABA treatment and increased exacerbations, COPD-related adverse events, or deaths. Where analyzed as an efficacy outcome, LABA treatment was generally associated with significant or numerical reductions in COPD exacerbations compared with placebo. Incidences of COPD-related adverse events were similar for active and placebo treatments. The incidence of adverse events typically associated with the β(2)-agonist drug class such as skeletal muscle tremors and palpitations was low (often <1% of patients), and there were no reports of increased incidence of cardiac arrhythmias. The systemic effects of β(2)-adrenoceptor stimulation, such as high glucose and potassium levels, were considered minor. CONCLUSION Current evidence from clinical studies of the safety and tolerability profile of LABAs supports their long-term use in COPD.
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Affiliation(s)
- Marc L Decramer
- Respiratory Division, UZ Leuven, Campus Gasthuisberg, Herestraat 49, Leuven, Belgium.
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56
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Arteaga-Solis E, Zee T, Emala CW, Vinson C, Wess J, Karsenty G. Inhibition of leptin regulation of parasympathetic signaling as a cause of extreme body weight-associated asthma. Cell Metab 2013; 17:35-48. [PMID: 23312282 PMCID: PMC3815545 DOI: 10.1016/j.cmet.2012.12.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 11/15/2012] [Accepted: 12/04/2012] [Indexed: 12/12/2022]
Abstract
Impaired lung function caused by decreased airway diameter (bronchoconstriction) is frequently observed whether body weight is abnormally high or low. That these opposite conditions affect the airways similarly suggests that the regulation of airway diameter and body weight are intertwined. We show here that, independently of its regulation of appetite, melanocortin pathway, or sympathetic tone, leptin is necessary and sufficient to increase airway diameter by signaling through its cognate receptor in cholinergic neurons. The latter decreases parasympathetic signaling through the M(3) muscarinic receptor in airway smooth muscle cells, thereby increasing airway diameter without affecting local inflammation. Accordingly, decreasing parasympathetic tone genetically or pharmacologically corrects bronchoconstriction and normalizes lung function in obese mice regardless of bronchial inflammation. This study reveals an adipocyte-dependent regulation of bronchial diameter whose disruption contributes to the impaired lung function caused by abnormal body weight. These findings may be of use in the management of obesity-associated asthma.
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Affiliation(s)
- Emilio Arteaga-Solis
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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57
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Oldenburger A, Maarsingh H, Schmidt M. Multiple facets of cAMP signalling and physiological impact: cAMP compartmentalization in the lung. Pharmaceuticals (Basel) 2012; 5:1291-331. [PMID: 24281338 PMCID: PMC3816672 DOI: 10.3390/ph5121291] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/15/2012] [Accepted: 11/20/2012] [Indexed: 12/20/2022] Open
Abstract
Therapies involving elevation of the endogenous suppressor cyclic AMP (cAMP) are currently used in the treatment of several chronic inflammatory disorders, including chronic obstructive pulmonary disease (COPD). Characteristics of COPD are airway obstruction, airway inflammation and airway remodelling, processes encompassed by increased airway smooth muscle mass, epithelial changes, goblet cell and submucosal gland hyperplasia. In addition to inflammatory cells, airway smooth muscle cells and (myo)fibroblasts, epithelial cells underpin a variety of key responses in the airways such as inflammatory cytokine release, airway remodelling, mucus hypersecretion and airway barrier function. Cigarette smoke, being next to environmental pollution the main cause of COPD, is believed to cause epithelial hyperpermeability by disrupting the barrier function. Here we will focus on the most recent progress on compartmentalized signalling by cAMP. In addition to G protein-coupled receptors, adenylyl cyclases, cAMP-specific phospho-diesterases (PDEs) maintain compartmentalized cAMP signalling. Intriguingly, spatially discrete cAMP-sensing signalling complexes seem also to involve distinct members of the A-kinase anchoring (AKAP) superfamily and IQ motif containing GTPase activating protein (IQGAPs). In this review, we will highlight the interaction between cAMP and the epithelial barrier to retain proper lung function and to alleviate COPD symptoms and focus on the possible molecular mechanisms involved in this process. Future studies should include the development of cAMP-sensing multiprotein complex specific disruptors and/or stabilizers to orchestrate cellular functions. Compartmentalized cAMP signalling regulates important cellular processes in the lung and may serve as a therapeutic target.
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Affiliation(s)
- Anouk Oldenburger
- Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy, University of Groningen, 9713 AV, Groningen, The Netherlands.
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Thanawala VJ, Forkuo GS, Al-Sawalha N, Azzegagh Z, Nguyen LP, Eriksen JL, Tuvim MJ, Lowder TW, Dickey BF, Knoll BJ, Walker JKL, Bond RA. β2-Adrenoceptor agonists are required for development of the asthma phenotype in a murine model. Am J Respir Cell Mol Biol 2012. [PMID: 23204390 DOI: 10.1165/rcmb.2012-0364oc] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
β(2)-Adrenoceptor (β2AR) agonists are the most effective class of bronchodilators and a mainstay of asthma management. The first potent β2AR agonist discovered and widely used in reversing the airway constriction associated with asthma exacerbation was the endogenous activator of the β2AR, epinephrine. In this study, we demonstrate that activation of the β2AR by epinephrine is paradoxically required for development of the asthma phenotype. In an antigen-driven model, mice sensitized and challenged with ovalbumin showed marked elevations in three cardinal features of the asthma phenotype: inflammatory cells in their bronchoalveolar lavage fluid, mucin over production, and airway hyperresponsiveness. However, genetic depletion of epinephrine using mice lacking the enzyme to synthesize epinephrine, phenylethanolamine N-methyltransferase, or mice that had undergone pharmacological sympathectomy with reserpine to deplete epinephrine, had complete attenuation of these three cardinal features of the asthma phenotype. Furthermore, administration of the long-acting β2AR agonist, formoterol, a drug currently used in asthma treatment, to phenylethanolamine N-methyltransferase-null mice restored the asthma phenotype. We conclude that β2AR agonist-induced activation is needed for pathogenesis of the asthma phenotype. These findings also rule out constitutive signaling by the β2AR as sufficient to drive the asthma phenotype, and may help explain why chronic administration of β2AR agonists, such as formoterol, have been associated with adverse outcomes in asthma. These data further support the hypothesis that chronic asthma management may be better served by treatment with certain "β-blockers."
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Affiliation(s)
- Vaidehi J Thanawala
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77204-5037, USA
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Dekkers BGJ, Racké K, Schmidt M. Distinct PKA and Epac compartmentalization in airway function and plasticity. Pharmacol Ther 2012; 137:248-65. [PMID: 23089371 DOI: 10.1016/j.pharmthera.2012.10.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 10/09/2012] [Indexed: 12/15/2022]
Abstract
Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases characterized by airway obstruction, airway inflammation and airway remodelling. Next to inflammatory cells and airway epithelial cells, airway mesenchymal cells, including airway smooth muscle cells and (myo)fibroblasts, substantially contribute to disease features by the release of inflammatory mediators, smooth muscle contraction, extracellular matrix deposition and structural changes in the airways. Current pharmacological treatment of both diseases intends to target the dynamic features of the endogenous intracellular suppressor cyclic AMP (cAMP). This review will summarize our current knowledge on cAMP and will emphasize on key discoveries and paradigm shifts reflecting the complex spatio-temporal nature of compartmentalized cAMP signalling networks in health and disease. As airway fibroblasts and airway smooth muscle cells are recognized as central players in the development and progression of asthma and COPD, we will focus on the role of cAMP signalling in their function in relation to airway function and plasticity. We will recapture on the recent identification of cAMP-sensing multi-protein complexes maintained by cAMP effectors, including A-kinase anchoring proteins (AKAPs), proteins kinase A (PKA), exchange protein directly activated by cAMP (Epac), cAMP-elevating seven-transmembrane (7TM) receptors and phosphodiesterases (PDEs) and we will report on findings indicating that the pertubation of compartmentalized cAMP signalling correlates with the pathopysiology of obstructive lung diseases. Future challenges include studies on cAMP dynamics and compartmentalization in the lung and the development of novel drugs targeting these systems for therapeutic interventions in chronic obstructive inflammatory diseases.
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Affiliation(s)
- Bart G J Dekkers
- Department of Molecular Pharmacology, University Center of Pharmacy, University of Groningen, The Netherlands.
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Nichols HL, Saffeddine M, Theriot BS, Hegde A, Polley D, El-Mays T, Vliagoftis H, Hollenberg MD, Wilson EH, Walker JKL, DeFea KA. β-Arrestin-2 mediates the proinflammatory effects of proteinase-activated receptor-2 in the airway. Proc Natl Acad Sci U S A 2012; 109:16660-5. [PMID: 23012429 PMCID: PMC3478622 DOI: 10.1073/pnas.1208881109] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Proteinase-Activated receptor-2 (PAR(2)), a G-protein-coupled Receptor, activated by serine proteinases, is reported to have both protective and proinflammatory effects in the airway. Given these opposing actions, both inhibitors and activators of PAR(2) have been proposed for treating asthma. PAR(2) can signal through two independent pathways: a β-arrestin-dependent one that promotes leukocyte migration, and a G-protein/Ca(2+) one that is required for prostaglandin E(2) (PGE(2)) production and bronchiolar smooth muscle relaxation. We hypothesized that the proinflammatory responses to PAR(2) activation are mediated by β-arrestins, whereas the protective effects are not. Using a mouse ovalbumin model for PAR(2)-modulated airway inflammation, we observed decreased leukocyte recruitment, cytokine production, and mucin production in β-arrestin-2(-/-) mice. In contrast, PAR(2)-mediated PGE(2) production, smooth muscle relaxation, and decreased baseline airway resistance (measures of putative PAR(2) "protective" effects) were independent of β-arrestin-2. Flow cytometry and cytospins reveal that lung eosinophil and CD4 T-cell infiltration, and production of IL-4, IL-6, IL-13, and TNFα, were enhanced in wild-type but not β-arrestin-2(-/-) mice. Using the forced oscillation technique to measure airway resistance reveals that PAR(2) activation protects against airway hyperresponsiveness by an unknown mechanism, possibly involving smooth muscle relaxation. Our data suggest that the PAR(2)-enhanced inflammatory process is β-arrestin-2 dependent, whereas the protective anticonstrictor effect of bronchial epithelial PAR(2) may be β-arrestin independent.
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Affiliation(s)
- Heddie L. Nichols
- Division of Biomedical Sciences, University of California, Riverside, CA 92521
| | | | - Barbara S. Theriot
- Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Durham, NC 27710; and
| | - Akhil Hegde
- Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Durham, NC 27710; and
| | | | - Tamer El-Mays
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada T2N 1N4
| | | | | | - Emma H. Wilson
- Division of Biomedical Sciences, University of California, Riverside, CA 92521
| | - Julia K. L. Walker
- Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center, Durham, NC 27710; and
| | - Kathryn A. DeFea
- Division of Biomedical Sciences, University of California, Riverside, CA 92521
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Billington CK, Hall IP. Novel cAMP signalling paradigms: therapeutic implications for airway disease. Br J Pharmacol 2012; 166:401-10. [PMID: 22013890 DOI: 10.1111/j.1476-5381.2011.01719.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Since its discovery over 50 years ago, cAMP has been the archetypal second messenger introducing students to the concept of cell signalling at the simplest level. As explored in this review, however, there are many more facets to cAMP signalling than the path from Gs-coupled receptor to adenylyl cyclase (AC) to cAMP to PKA to biological effect. After a brief description of this canonical cAMP signalling pathway, a snapshot is provided of the novel paradigms of cAMP signalling. As in the airway the cAMP pathway relays the major bronchorelaxant signal and as such is the target for frontline therapy for asthma and COPD, particular emphasis is given to airway disease and therapy. Areas discussed include biased agonism, continued signalling following internalization, modulation of cAMP by AC, control of cAMP degradation, cAMP and calcium crosstalk, Epac-mediated signalling and finally the implications of altered genotypes will be considered. LINKED ARTICLES This article is part of a themed section on Novel cAMP Signalling Paradigms. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.166.issue-2.
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Affiliation(s)
- Charlotte K Billington
- Division of Therapeutics and Molecular Medicine, Nottingham Respiratory Biomedical Research Unit, The University of Nottingham, Nottingham, UK.
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Siddiqui S, Redhu NS, Ojo OO, Liu B, Irechukwu N, Billington C, Janssen L, Moir LM. Emerging airway smooth muscle targets to treat asthma. Pulm Pharmacol Ther 2012; 26:132-44. [PMID: 22981423 DOI: 10.1016/j.pupt.2012.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 07/28/2012] [Accepted: 08/27/2012] [Indexed: 11/26/2022]
Abstract
Asthma is characterized in part by variable airflow obstruction and non-specific hyperresponsiveness to a variety of bronchoconstrictors, both of which are mediated by the airway smooth muscle (ASM). The ASM is also involved in the airway inflammation and airway wall remodeling observed in asthma. For all these reasons, the ASM provides an important target for the treatment of asthma. Several classes of drugs were developed decades ago which targeted the ASM - including β-agonists, anti-cholinergics, anti-histamines and anti-leukotrienes - but no substantially new class of drug has appeared recently. In this review, we summarize the on-going work of several laboratories aimed at producing novel targets and/or tools for the treatment of asthma. These range from receptors and ion channels on the ASM plasmalemma, to intracellular effectors (particularly those related to cyclic nucleotide signaling, calcium-homeostasis and phosphorylation cascades), to anti-IgE therapy and outright destruction of the ASM itself.
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Affiliation(s)
- Sana Siddiqui
- Meakins-Christie Laboratories, Department of Medicine, McGill University, 3626 St Urbain, Montréal, Québec H2X 2P2, Canada
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Short PM, Williamson PA, Lipworth BJ. Effects of hydrocortisone on acute β-adrenoceptor blocker and histamine induced bronchoconstriction. Br J Clin Pharmacol 2012; 73:717-26. [PMID: 22077869 DOI: 10.1111/j.1365-2125.2011.04143.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIMS β-adrenoceptor blockers are avoided in asthma due to concerns of bronchoconstriction. We investigated the safety of acute exposure to propranolol in asthmatics, sequentially challenged with histamine to mimic an asthma exacerbation and evaluated the role of intravenous hydrocortisone in potentiating salbutamol reversibility. METHODS Persistent atopic asthmatics, requiring ≤ 1000 µg day(-1) budesonide, performed a randomized double-blind placebo-controlled crossover study. Following 10 mg or 20 mg of oral propranolol, patients received 400 mg intravenous hydrocortisone or placebo, followed by histamine challenge with nebulized salbutamol 5 mg and ipratropium 500 µg recovery. RESULTS Thirteen patients completed per protocol. Hydrocortisone did not potentiate salbutamol recovery post propranolol and histamine challenge vs. placebo (mean difference in FEV(1) 0.04 ml, 95% CI -0.07, 0.15, P= 0.417). β-adrenoceptor blocker induced bronchoconstriction was demonstrated by spirometry and impulse oscillometry. For the placebo visit, FEV(1) fell 4.7% 2 hours post propranolol (95% CI 1.8, 7.5, P= 0.008) whilst total airway resistance (R5%) increased 31.3% (95% CI 15.6, 47.0, P= 0.04). On both visits FEV(1) % and R5% returned to baseline after salbutamol post histamine. CONCLUSION Nebulized salbutamol and ipratropium produced a full recovery after propranolol and histamine induced bronchoconstriction, independent of hydrocortisone use. Since the greatest risk of β-adrenoceptor blockade is after first dose, our findings offer reassurance to those undertaking further evaluation of chronic β-adrenoceptor blockade as a potential treatment for mild-to-moderate asthma.
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Affiliation(s)
- Philip M Short
- Asthma and Allergy Research Group, Centre for Cardiovascular and Lung Biology, Division of Medical Sciences, University of Dundee, Dundee, UK
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Lin R, Degan S, Theriot BS, Fischer BM, Strachan RT, Liang J, Pierce RA, Sunday ME, Noble PW, Kraft M, Brody AR, Walker JKL. Chronic treatment in vivo with β-adrenoceptor agonists induces dysfunction of airway β(2) -adrenoceptors and exacerbates lung inflammation in mice. Br J Pharmacol 2012; 165:2365-77. [PMID: 22013997 DOI: 10.1111/j.1476-5381.2011.01725.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Inhalation of a β-adrenoceptor agonist (β-agonist) is first-line asthma therapy, used for both prophylaxis against, and acute relief of, bronchoconstriction. However, repeated clinical use of β-agonists leads to impaired bronchoprotection and, in some cases, adverse patient outcomes. Mechanisms underlying this β(2) -adrenoceptor dysfunction are not well understood, due largely to the lack of a comprehensive animal model and the uncertainty as to whether or not bronchorelaxation in mice is mediated by β(2) -adrenoceptors. Thus, we aimed to develop a mouse model that demonstrated functional β-agonist-induced β(2) -adrenoceptor desensitization in the context of allergic inflammatory airway disease. EXPERIMENTAL APPROACH We combined chronic allergen exposure with repeated β-agonist inhalation in allergen-treated BALB/C mice and examined the contribution of β(2) -adrenoceptors to albuterol-induced bronchoprotection using FVB/NJ mice with genetic deletion of β(2) -adrenoceptors (KO). Associated inflammatory changes - cytokines (ELISA), cells in bronchoalevolar lavage and airway remodelling (histology) and β(2) -adrenoceptor density (radioligand binding) - were also measured. KEY RESULTS β(2) -Adrenoceptors mediated albuterol-induced bronchoprotection in mice. Chronic treatment with albuterol induced loss of bronchoprotection, associated with exacerbation of the inflammatory components of the asthma phenotype. CONCLUSIONS AND IMPLICATIONS This animal model reproduced salient features of human asthma and linked loss of bronchoprotection with airway pathobiology. Accordingly, the model offers an advanced tool for understanding the mechanisms of the effects of chronic β- agonist treatment on β-adrenoceptor function in asthma. Such information may guide the clinical use of β-agonists and provide insight into development of novel β-adrenoceptor ligands for the treatment of asthma.
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Affiliation(s)
- Rui Lin
- Duke University Medical Center, Durham, NC, USA
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65
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Cazzola M, Page CP, Calzetta L, Matera MG. Pharmacology and therapeutics of bronchodilators. Pharmacol Rev 2012; 64:450-504. [PMID: 22611179 DOI: 10.1124/pr.111.004580] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.
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Affiliation(s)
- Mario Cazzola
- Università di Roma Tor Vergata, Dipartimento di Medicina Interna, Via Montpellier 1, 00133 Roma, Italy.
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66
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Matera MG, Calzetta L, Rinaldi B, Cazzola M. Treatment of COPD: moving beyond the lungs. Curr Opin Pharmacol 2012; 12:315-22. [PMID: 22552103 DOI: 10.1016/j.coph.2012.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 03/14/2012] [Accepted: 04/04/2012] [Indexed: 01/07/2023]
Abstract
We still do not know whether the successful treatment of the comorbid diseases associated with COPD, mainly cardiovascular disease, also positively influences the course of the lung disease because so far there are few definite data documenting that treatment of COPD comorbidities will reduce morbidity and mortality rates in these patients. Observational studies suggest that COPD patients treated with statins, angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers, and β-adrenoceptor blockers may have improved survival and reduced hospitalisation from exacerbations. Progress in basic and translational research has led to a better understanding of pharmacological mechanisms that may explain the effects of these drugs on COPD and some small clinical trial activity is beginning to generate promising results.
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Affiliation(s)
- M Gabriella Matera
- Department of Experimental Medicine, Second University of Naples, Naples, Italy.
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67
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Nguyen LP, Singh B, Okulate AA, Alfaro VY, Tuvim MJ, Dickey BF, Bond RA. Complementary anti-inflammatory effects of a β-blocker and a corticosteroid in an asthma model. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2012; 385:203-10. [PMID: 21964666 DOI: 10.1007/s00210-011-0692-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 09/05/2011] [Indexed: 02/03/2023]
Abstract
Glucocorticosteroids are the mainstay treatment for chronic asthma; however, adverse effects can limit their usefulness. We previously determined in experimental asthma that chronic administration of β₂-adrenoceptor inverse agonists reduced airway hyperresponsiveness and indexes of inflammation. However, the effect of co-administration of glucocorticosteroids with β₂-adrenoceptor inverse agonists is unknown. Therefore, we evaluated the anti-inflammatory effect of co-administration of dexamethasone, a glucocorticosteroid, and nadolol, a β₂-inverse agonist, in a murine asthma model. We measured eosinophils and cytokines in bronchoalveolar lavage fluid and mucin content in epithelial cells after exposure to different concentrations of dexamethasone and nadolol. Dexamethasone was administered for 3 days and nadolol for 24 days prior to ovalbumin challenge. Both drugs were continued during five daily intranasal challenges with ovalbumin. Independent administration of dexamethasone (0.4 mg/kg/day) or nadolol (25 ppm) reduced bronchoalveolar lavage eosinophils by 58% and 36%, respectively (P < 0.05). Co-administration of both drugs yielded an additive reduction in eosinophils (81%, P < 0.05). Co-administration of both drugs (dexamethasone 0.4 mg/kg/day and nadolol 25 ppm) also yielded a greater reduction in mucin volume density (83%) than either drug alone (18% for dexamethasone and 62% for nadolol) and greater than high-dose dexamethasone (71%) alone (P < 0.05). Similarly, co-administration of both drugs (dexamethasone 0.4 mg/kg/day and nadolol 25 ppm) yielded an additive effect on the reduction of type 2 cytokines in bronchoalveolar lavage fluid equivalent to the administration of a 10-fold higher dose of dexamethasone. In Summary, the simultaneous administration of a glucocorticosteroid and a β₂-adrenoceptor inverse agonist was more effective at reducing indexes of airway inflammation than either drug given alone; suggesting nadolol may possess "glucocorticoid-sparing" properties.
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Affiliation(s)
- Long P Nguyen
- Department of Pulmonary Medicine, MD Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, TX 77030, USA
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68
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Hu Z, Chen R, Cai Z, Yu L, Fei Y, Weng L, Wang J, Ge X, Zhu T, Wang J, Bai C. Salmeterol attenuates the inflammatory response in asthma and decreases the pro-inflammatory cytokine secretion of dendritic cells. Cell Mol Immunol 2012; 9:267-75. [PMID: 22231554 DOI: 10.1038/cmi.2011.56] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Salmeterol is a long-acting β2-agonist that activates adenylate cyclase, causing long-lasting bronchodilation and has been used for many years to control asthma. However, little information is available about the immunoregulatory effects of salmeterol. We found that salmeterol decreases the production of pro-inflammatory cytokines in a model of allergen-challenged mice that expressed tumor-necrosis factor-alpha, interleukin-1 and interleukin-6. Dendritic cells (DCs) are antigen-presenting cells and act as sentinels in the airway. We found that salmeterol (10(-5) mol/l) reduced the inflammation caused by lipopolysaccharide (0.1 µg/ml) in activated murine bone marrow-derived DCs. Moreover, western blots demonstrated that this protective effect was mediated partially by inhibiting signaling through the nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK) pathways and dramatically decreased levels of p-ERK. We suggest that salmeterol regulates the inflammation of allergen-induced asthma by modulating DCs. In conclusion, we provide evidence that DCs are the target immune cells responsible for the action of salmeterol against asthma.
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Affiliation(s)
- Zhenli Hu
- Department of Respiratory Medicine, Changhai Hospital, the Second Military Medical University, Shanghai 200433, China
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69
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Abstract
The acute and chronic effects of certain drugs can often be opposite. For example, in congestive heart failure acute administration of β-adrenoceptor agonists results in beneficial improvement in symptoms of the disease, but their chronic use increases mortality. Conversely, certain β-adrenoceptor antagonists/inverse agonists (β-blockers) initially cause a detrimental response by decreasing cardiac contractility in congestive heart failure, whereas chronic treatment with the same β-blockers improves contractility and survival. Furthermore, this time-dependent reversal of outcomes occurs in nonpharmacological interventions, such as exercise, and can even be observed in the response of plants to pruning or other stressors, with the results being a different short-term versus long-term effect. Here, we review some of these phenomena with a special emphasis on the temporal dissociation of pharmacological effects. Although Francis Colpaert used this knowledge to lead a drug discovery project for an analgesic compound that initially produced hyperalgesia, we focused on examples outside the central nervous system.
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Abstract
Short-acting β2-agonists (SABAs) and long-acting β2-agonists (LABAs) are both important for treatment of asthma and chronic obstructive pulmonary disease (COPD) because of their bronchodilator and bronchoprotective effects. However, the use of these agonists, at least for asthma, has generated some controversy because of their association with increased mortality. Pharmacogenetics is the study of genetically determined variation in response to medications, which might prove useful for target therapies in highly responsive patients, especially for more expensive therapies or those with increased risk of side effects. Variation in response to both SABAs and LABAs has been observed in patients with polymorphisms in the β2 adrenoceptor gene (ADRB2). This review summarizes results from various studies on the possible relationship between ADRB2 polymorphisms and the bronchodilator or bronchoprotective effects of inhaled β2-agonists. By assessing the ADRB2 genotype, the hope is that it will be possible to predict the responsiveness to chronic administration of β2-agonists. Genetic testing, however, is of limited usefulness at this stage for ADRB2 because the common variants identified thus far account for only a small proportion of the variation observed for given responses. Carefully performed and adequately powered clinical trials continue to be important for achieving the goal of pharmacogenetic approaches to therapy.
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Affiliation(s)
- Nobuyuki Hizawa
- Department of Pulmonary Medicine, Institute of Clinical Medicine, University of Tsukuba, Japan.
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71
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Abstract
Current therapy for asthma is highly effective. β(2)-Adrenergic receptor (β(2)AR) agonists are the most effective bronchodilators and relax airway smooth muscle cells through increased cAMP concentrations and directly opening large conductance Ca(2+) channels. β(2)AR may also activate alternative signaling pathways that may have detrimental effects in asthma. Glucocorticoids are the most effective anti-inflammatory treatments and switch off multiple activated inflammatory genes through recruitment of histone deacetylase-2, activating anti-inflammatory genes, and through increasing mRNA stability of inflammatory genes. There are beneficial molecular interactions between β(2)AR and glucocorticoid-activated pathways. Understanding these signaling pathways may lead to even more effective therapies in the future.
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Affiliation(s)
- Peter J Barnes
- National Heart and Lung Institute, Imperial College, London SW3 6LY, United Kingdom.
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72
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Walker JKL, Penn RB, Hanania NA, Dickey BF, Bond RA. New perspectives regarding β(2) -adrenoceptor ligands in the treatment of asthma. Br J Pharmacol 2011; 163:18-28. [PMID: 21175591 DOI: 10.1111/j.1476-5381.2010.01178.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In the last two decades several significant changes have been proposed in the receptor theory that describes how ligands can interact with G protein-coupled receptors (GPCRs). Here we briefly summarize the evolution of receptor theory and detail recent prominent advances. These include: (i) the existence of spontaneously active GPCRs that are capable of signalling even though they are unoccupied by any ligand; (ii) the discovery of ligands that can inactivate these spontaneously active receptors; (iii) the notion that a ligand may simultaneously activate more than one GPCR signalling pathway; and (iv) the notion that certain ligands may be able to preferentially direct receptor signalling to a specific pathway. Because the data supporting these receptor theory ideas are derived primarily from studies using artificial expression systems, the physiological relevance of these new paradigms remains in question. As a potential example of how these new perspectives in receptor theory relate to drug actions and clinical outcomes, we discuss their relevance to the recent controversy regarding the chronic use of β(2) -adrenoceptor agonists in the treatment of asthma.
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Affiliation(s)
- J K L Walker
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
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73
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Ferrie AM, Sun H, Fang Y. Label-free integrative pharmacology on-target of drugs at the β(2)-adrenergic receptor. Sci Rep 2011; 1:33. [PMID: 22355552 PMCID: PMC3216520 DOI: 10.1038/srep00033] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 06/23/2011] [Indexed: 12/22/2022] Open
Abstract
We describe a label-free integrative pharmacology on-target (iPOT) method to assess the pharmacology of drugs at the β(2)-adrenergic receptor. This method combines dynamic mass redistribution (DMR) assays using an array of probe molecule-hijacked cells with similarity analysis. The whole cell DMR assays track cell system-based, ligand-directed, and kinetics-dependent biased activities of the drugs, and translates their on-target pharmacology into numerical descriptors which are subject to similarity analysis. We demonstrate that the approach establishes an effective link between the label-free pharmacology and in vivo therapeutic indications of drugs.
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Affiliation(s)
- Ann M Ferrie
- Biochemical Technologies, Science and Technology Division, Corning Inc., Corning, NY 14831, USA
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74
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Riesenfeld EP, Irvin CG. Asthma treatment through the beta receptor: lessons from animal models. Front Biosci (Elite Ed) 2011; 3:1201-8. [PMID: 21622126 PMCID: PMC8669294 DOI: 10.2741/e323] [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] [Indexed: 11/22/2022]
Abstract
Asthma is a significant health problem worldwide with a prevalence that continues to rise and for which there is no cure. Animal models have been used for decades to investigate the cause and cures of asthma, and while they do not always mimic many of the facets of this syndrome, mechanistic animal studies are still nevertheless very useful. Animal studies with beta-agonists suggest much broader and perhaps more important roles for beta-agonists since beta-agonists reduce aspects of inflammation and may affect structural remodeling. Studies using enantiomers of beta-agonists provide a confusing picture of the degree and mechanism of the deleterious effects of racemic mixtures and/or the S-enantiomer or other classes of beta-agonists. Neural mechanisms are implicated. The future holds a promise of even more insight into the mechanisms of the acute and chronic role of the beta-adrenoceptor, asthma therapeutics, in particular, beta-agonists that will lead to a better understanding of the pathogenesis and treatment of asthma.
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Affiliation(s)
- Erik P Riesenfeld
- Vermont Lung Center, College of Medicine, University of Vermont, Burlington, VT 05405-0075, USA
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75
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Chung LP, Waterer G, Thompson PJ. Pharmacogenetics of β2 adrenergic receptor gene polymorphisms, long-acting β-agonists and asthma. Clin Exp Allergy 2011; 41:312-26. [PMID: 21294785 DOI: 10.1111/j.1365-2222.2011.03696.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adrenergic β2 receptor (ADRβ2) agonists are widely used in asthma. Approximately 10% of patients have severe, poorly controlled disease despite extensive use of ADRβ2 agonists. Variations in responses to ADRβ2 agonists can, in part, be attributed to genetic variation, with 49 different polymorphisms having been identified for the ADRβ2 gene. Although clear associations exist between ADRβ2 gene polymorphisms, such as +46G>A, and patient response, the importance of these polymorphisms remains controversial. Patient selection, the number of polymorphisms analysed, differences in the type/dose of ADRβ2 agonist, use of inhaled corticosteroids and population sizes have all varied. Most studies were limited to mild or moderate asthmatics using ADRβ2 agonists sparingly. It is difficult to extrapolate from these studies to individual patients who have severe asthma, use a variety of ADRβ2 agonists and do so frequently. The extent to which ADRβ2 gene polymorphisms are relevant to asthma management needs further review, both clinically and at the molecular level. In vitro studies have helped to define the functional changes induced by specific ADRβ2 gene polymorphisms, including 3'-untranslated region poly-C repeat. The resulting ADRβ2 gene haplotypes (rather than genotypes), the interactions among ADRβ2 gene haplotypes and variations in the chemistry of different agonists deserve more detailed assessment. Responses to ADRβ2 agonists depend on effective downstream signalling following ADRβ2 activation and also on receptor regulation. Studies on other regulators of ADRβ2 receptor signalling and trafficking may be equally important in understanding the functional role of ADRβ2 gene polymorphisms. The role of ADRβ2 gene polymorphisms in the pathogenesis and management of severe asthma cannot be clearly defined until more specific and targeted research studies are performed.
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Affiliation(s)
- L P Chung
- Genetics Unit, Lung Institute of Western Australia, Centre for Asthma, Allergy and Respiratory Research, Perth, WA, Australia
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76
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Page C. Paradoxical pharmacology: turning our pharmacological models upside down. Trends Pharmacol Sci 2011; 32:197-200. [PMID: 21458081 DOI: 10.1016/j.tips.2011.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 02/11/2011] [Accepted: 02/11/2011] [Indexed: 01/13/2023]
Abstract
Paradoxical pharmacology is a term first suggested by Richard Bond to refer to intriguing observations that chronic use of some drug types can have the opposite biological effect(s) to those seen following acute administration of the same drug. A good example of 'paradoxical pharmacology' is the research Richard has pioneered showing that whereas acute administration of β-blockers is contraindicated in the treatment of asthma, chronic use of certain β-blockers can have therapeutic benefit. It would appear that those β-blockers that can act as inverse agonists at the β2 receptor particularly show this paradoxical effect and the findings of Richard's research not only challenge the dogma of the treatment of asthma but also challenge many of the pharmacological principles of ligand/receptor interactions established by Sir James Black and others. In this paper, I discuss Richard's efforts to evaluate the chronic effects of β-blockers in the airways and how this research caught the imagination of Sir James Black.
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Affiliation(s)
- Clive Page
- Sackler Institute of Pulmonary Pharmacology, Institute of Pharmaceutical Science, Franklin Wilkins Building, Waterloo Campus, King's College London, 150 Stamford Street, London SE1 9NH, UK.
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77
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Daly CJ, McGrath JC. Previously unsuspected widespread cellular and tissue distribution of β-adrenoceptors and its relevance to drug action. Trends Pharmacol Sci 2011; 32:219-26. [PMID: 21429599 DOI: 10.1016/j.tips.2011.02.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 02/11/2011] [Accepted: 02/11/2011] [Indexed: 01/05/2023]
Abstract
The discovery of β-adrenoceptors in previously unsuspected cell types is contributing to the rethinking of new drug targets. Recent developments in β-adrenoceptor pharmacology might have excited and surprised James Black, given his interest in developing drugs based on the selective manipulation of receptors to alter physiological responses. β-adrenoceptors continue to generate surprises at molecular and pharmacological levels that often require knowledge of receptor location to interpret. In this review, we emphasize the use of fluorescent ligands as the most selective means of demonstrating receptor localization. Fluorescent ligand binding in live tissues can provide quantitative pharmacological data, under carefully controlled conditions, relevant to other signalling parameters. Consideration of the role of β-adrenoceptors in many cell types (previously ignored) is needed to understand the actions of drugs at β-adrenoceptors throughout the body, particularly in the lung epithelium, vascular endothelium, immune cells and other 'structural' and 'restorative' cell types.
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Affiliation(s)
- C J Daly
- School of Life Sciences, College of Medical, Veterinary and Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK.
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78
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Peng H, Bond RA, Knoll BJ. The effects of acute and chronic nadolol treatment on β2AR signaling in HEK293 cells. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2011; 383:209-16. [PMID: 21225244 DOI: 10.1007/s00210-010-0591-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 12/17/2010] [Indexed: 12/24/2022]
Abstract
Nadolol (NAD) is a β-adrenergic receptor blocker with inverse agonist activity at βARs. Previous studies in our laboratory showed that chronic treatment with NAD decreased airway resistance response (R (aw)) to the muscarinic agonist methacholine in a murine model of asthma while acute treatment with NAD increased R (aw) (Callaerts-Vegh et al., Proc Natl Acad Sci U S A 101:4948-4953, 2004). Chronic treatment with NAD also caused decreased airway inflammation and mucin content in a murine asthma model (Nguyen et al., Am J Respir Cell Mol Biol 38:256-262, 2008). In this study, we examined the effects of nadolol on β(2)AR levels and signaling components downstream of the β(2)AR using a line of HEK293 cells expressing human β(2)ARs. Chronic treatment with NAD increased β(2)AR protein levels and decreased receptor degradation, consistent with receptor stabilization by the inverse agonist. Basal cAMP levels decreased after 5 min of treatment with NAD but increased after a 24-h treatment. A 5-min treatment with NAD decreased forskolin-stimulated phosphorylation at the β(2)AR PKA site Ser 262 while a 24-h treatment with NAD increased it. In contrast, chronic treatment with NAD had no effect on phosphorylation of the β(2)AR GRK site at Ser 355, 356. Chronic treatment with NAD upregulated cellular levels of G(α)s but had no effect on G(α)i. Chronic NAD treatment therefore increases cellular cAMP levels by mechanisms that include the upregulation of β(2)AR and G(α)s. This effect may explain in part the beneficial effects of chronic nadolol treatment on airway contractility.
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Affiliation(s)
- Hui Peng
- Department of Biology and Biochemistry, University of Houston, Science and Research Bldg 2, Rm 369, Houston, TX 77204-5001, USA.
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79
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Yang Z, Cooper PR, Damera G, Mukhopadhyay I, Cho H, Kehrl JH, Panettieri RA, Druey KM. Beta-agonist-associated reduction in RGS5 expression promotes airway smooth muscle hyper-responsiveness. J Biol Chem 2011; 286:11444-55. [PMID: 21278382 DOI: 10.1074/jbc.m110.212480] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although short-acting and long-acting inhaled β(2)-adrenergic receptor agonists (SABA and LABA, respectively) relieve asthma symptoms, use of either agent alone without concomitant anti-inflammatory drugs (corticosteroids) may increase the risk of disease exacerbation in some patients. We found previously that pretreatment of human precision-cut lung slices (PCLS) with SABA impaired subsequent β(2)-agonist-induced bronchodilation, which occurred independently of changes in receptor quantities. Here we provide evidence that prolonged exposure of cultured human airway smooth muscle (HuASM) cells to β(2)-agonists directly augments procontractile signaling pathways elicited by several compounds including thrombin, bradykinin, and histamine. Such treatment did not increase surface receptor amounts or expression of G proteins and downstream effectors (phospholipase Cβ and myosin light chain). In contrast, β-agonists decreased expression of regulator of G protein signaling 5 (RGS5), which is an inhibitor of G-protein-coupled receptor (GPCR) activity. RGS5 knockdown in HuASM increased agonist-evoked intracellular calcium flux and myosin light chain (MLC) phosphorylation, which are prerequisites for contraction. PCLS from Rgs5(-/-) mice contracted more to carbachol than those from WT mice, indicating that RGS5 negatively regulates bronchial smooth muscle contraction. Repetitive β(2)-agonist use may not only lead to reduced bronchoprotection but also to sensitization of excitation-contraction signaling pathways as a result of reduced RGS5 expression.
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Affiliation(s)
- Zhao Yang
- Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
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80
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Affiliation(s)
- John V Fahy
- Cardiovascular Research Institute and Department of Medicine, University of California, San Francisco, USA
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81
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Dickey BF, Walker JKL, Hanania NA, Bond RA. beta-Adrenoceptor inverse agonists in asthma. Curr Opin Pharmacol 2010; 10:254-9. [PMID: 20399707 DOI: 10.1016/j.coph.2010.03.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/12/2010] [Accepted: 03/17/2010] [Indexed: 01/14/2023]
Abstract
Beta(2)-adrenoceptor (beta(2)-AR) agonists are very effective bronchodilators and play a major role in every stage of asthma management. However, their chronic, regular use is associated with detrimental effects including an increase in asthma-related deaths. Conversely, recent data suggest that certain beta-blockers, specifically beta-adrenoceptor (beta-AR) inverse agonists, may be useful in the chronic treatment of asthma. Here we review the data for this observation and the signaling pathways that may be involved. The data suggest that beta(2)-AR signaling is required to produce maximal airway inflammation and hyperresponsiveness, and the signaling pathway responsible for these effects is likely the non-canonical beta-arrestin-2 pathway. Therefore, beta-AR inverse agonists may produce their beneficial chronic effects by inhibiting constitutive or ligand-induced activation of this pathway. Both lung parenchymal and hematopoietic cells appear to be involved in mediating the beneficial effects of beta-AR inverse agonists.
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Affiliation(s)
- Burton F Dickey
- Department of Pulmonary Medicine, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
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82
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Polikepahad S, Knight JM, Naghavi AO, Oplt T, Creighton CJ, Shaw C, Benham AL, Kim J, Soibam B, Harris RA, Coarfa C, Zariff A, Milosavljevic A, Batts LM, Kheradmand F, Gunaratne PH, Corry DB. Proinflammatory role for let-7 microRNAS in experimental asthma. J Biol Chem 2010; 285:30139-49. [PMID: 20630862 DOI: 10.1074/jbc.m110.145698] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs (miRNAs) are short, non-coding RNAs that target and silence protein coding genes through 3'-UTR elements. Evidence increasingly assigns an immunosuppressive role for miRNAs in immunity, but relatively few miRNAs have been studied, and an overall understanding of the importance of these regulatory transcripts in complex in vivo systems is lacking. Here we have applied multiple technologies to globally analyze miRNA expression and function in allergic lung disease, an experimental model of asthma. Deep sequencing and microarray analyses of the mouse lung short RNAome revealed numerous extant and novel miRNAs and other transcript classes. Similar to mRNAs, lung miRNA expression changed dynamically during the transition from the naive to the allergic state, suggesting numerous functional relationships. A possible role for miRNA editing in altering the lung mRNA target repertoire was also identified. Multiple members of the highly conserved let-7 miRNA family were the most abundant lung miRNAs, and we confirmed in vitro that interleukin 13 (IL-13), a cytokine essential for expression for allergic lung disease, is regulated by mmu-let-7a. However, inhibition of let-7 miRNAs in vivo using a locked nucleic acid profoundly inhibited production of allergic cytokines and the disease phenotype. Our findings thus reveal unexpected complexity in the miRNAome underlying allergic lung disease and demonstrate a proinflammatory role for let-7 miRNAs.
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83
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Current world literature. Curr Opin Allergy Clin Immunol 2010; 10:87-92. [PMID: 20026987 DOI: 10.1097/aci.0b013e3283355458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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84
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Nino G, Grunstein MM. Current concepts on the use of glucocorticosteroids and beta-2-adrenoreceptor agonists to treat childhood asthma. Curr Opin Pediatr 2010; 22:290-5. [PMID: 20164771 PMCID: PMC2997654 DOI: 10.1097/mop.0b013e328337cb0c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE OF REVIEW This article reviews current concepts regarding the clinical and scientific rationale for the combined use of glucocorticosteroids and beta-2-adrenoreceptor (beta2AR) agonists in the treatment of childhood asthma. RECENT FINDINGS Several studies have demonstrated that inhaled corticosteroids (ICS) and beta2AR agonists are the most effective medications for the management of asthma in children. Given substantial evidence of an increased clinical benefit when these agents are used together, new studies are being pursued to establish the efficacy and safety of this combinational therapy in infants and children. Ongoing research is also investigating the mechanisms of beta2AR and glucocorticosteroids signaling and their molecular interactions. This new knowledge will likely lead to novel therapeutic approaches to asthma control. SUMMARY There is increasing evidence demonstrating that the combination of long-acting beta2AR agonists and ICS may be more effective than high-dose ICS therapy alone in the management of children with uncontrolled asthma. In addition, the use of a single inhaler containing ICS and a quick-acting beta2AR agonist might be a convenient alternative to prevent and treat asthma exacerbations. Future investigations should be designed to more specifically evaluate the efficacy and safety of these therapies in the different asthmatic phenotypes of infants and children.
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Affiliation(s)
- Gustavo Nino
- Division of Pediatric Pulmonology, Penn State Milton S. Hershey Children's Hospital, Penn State College of Medicine, Hershey, Pennsylvania 17033-0850, USA.
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Loza MJ, Penn RB. Regulation of T cells in airway disease by beta-agonist. Front Biosci (Schol Ed) 2010; 2:969-79. [PMID: 20515836 DOI: 10.2741/s113] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It is widely recognized that Th2 cytokines derived from T cells play a major role in the development of allergic lung inflammation that causes most asthma. Beta-agonists are important rescue and maintenance therapies for asthma, yet our understanding of beta-agonist effects on T cell biology is surprisingly poor. Recent studies using both cell culture and more integrative models are beginning to reveal beta-agonist regulation of T cell signaling and function that may be important in the pathogenesis and treatment of asthma and possibly other inflammatory diseases. Here we provide a comprehensive review of the literature concerning beta-agonist effects on T cells, and discuss the relevance of emerging paradigms of beta-adrenergic receptor signaling to T cell function.
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Affiliation(s)
- Matthew J Loza
- Department of Medicine, Division of Pulmonary and Critical Care Medicine University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Clinical implications of the intrinsic efficacy of beta-adrenoceptor drugs in asthma: full, partial and inverse agonism. Curr Opin Pulm Med 2010; 16:1-5. [PMID: 19887938 DOI: 10.1097/mcp.0b013e328333def8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW beta2-Adrenoceptor (AR) agonists are the most effective bronchodilators known, and play important roles in every step of asthma therapy. Intrinsic efficacy is an important pharmacological property that differentiates the clinical effects and safety profile of beta2-AR agonists. We review the role of beta2-AR agonist intrinsic efficacy in asthma treatment focusing on recent literature. RECENT FINDINGS In acute asthma, a full agonist (high intrinsic efficacy) offers a clinical advantage over a partial agonist (low intrinsic efficacy) but with the potential of inducing dose-dependent adverse effects. The chronic use of beta2-AR agonists may be associated with several adverse outcomes including loss of asthma control and even increased mortality. Recently, the role of beta-AR inverse agonists (beta-blockers) which have a negative intrinsic efficacy was studied. Whereas contraindicated in acute asthma, preliminary data suggest that the chronic use of these agents may be associated with attenuation of airway hyper-responsiveness in patients with mild asthma. Studies in a murine model of asthma suggest that such effects may be related to decreased airway inflammation and mucous metaplasia. SUMMARY Rational choice among beta2-AR agonists in acute and chronic asthma should be influenced by differences in intrinsic efficacy among these agents. In acute severe asthma, a full agonist offers a clinical advantage over a partial agonist. Whereas the use of inverse agonists in the treatment of asthma is still experimental and needs further exploration in future trials, preliminary studies suggest that their chronic use is well tolerated and is associated with decreased airway hyper-responsiveness.
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87
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Current world literature. Curr Opin Pulm Med 2010; 16:77-82. [PMID: 19996898 DOI: 10.1097/mcp.0b013e328334fe23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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88
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Fitzgerald PJ. Is elevated noradrenaline an aetiological factor in a number of diseases? ACTA ACUST UNITED AC 2009; 29:143-56. [PMID: 19740085 DOI: 10.1111/j.1474-8665.2009.00442.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
1 Here I put forth the hypothesis that noradrenaline (NA), which is a signalling molecule in the brain and sympathetic nervous system (SNS), is an aetiological factor in a number of diseases. 2 In a previous paper (Fitzgerald, Int. J. Cancer, 124, 2009, 257), I examined evidence that elevated NA is a factor in various types of cancer. Here I extend the argument to several other diseases, including diabetes mellitus, open-angle glaucoma, osteoarthritis and rheumatoid arthritis and asthma. 3 The principal hypothesis is that, largely as a result of genetics, elevated noradrenergic tone in the SNS predisposes a large number of individuals to a broad range of diseases. 4 For each of the above five diseases, I briefly examine the following four lines of evidence to assess the hypothesis: i) whether pharmacological studies in rodents that manipulate NA levels or receptors affect these diseases; ii) whether pharmacological manipulation of NA in humans affects these diseases; iii) whether bipolar disorder, excessive body weight, and hypertension, which may all three involve elevated NA, tend to be comorbid with these diseases and iv) whether psychological stressors tend to cause or exacerbate these conditions, since psychological stress is associated with increased release of NA. 5 The four lines of evidence tend to support the hypothesis.
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Affiliation(s)
- P J Fitzgerald
- The Zanvyl Krieger Mind/Brain Institute, Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, 338 Krieger Hall, 3400 N Charles St, Baltimore, MD 21218, USA
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Abstract
Asthma was originally thought to be associated with an intrinsic defect in beta2ADR (beta2-adrenoceptor) function, tipping the balance towards parasympathetic bronchoconstriction. Hence beta-blocking drugs (such as beta2ADR antagonists and inverse agonists) may cause acute bronchoconstriction which, in turn, may be attenuated by anti-cholinergic agents. Although beta2-agonists are highly effective for the acute relief of bronchoconstriction, their chronic use is accompanied by an adaptive reduction in beta2ADR numbers and associated desensitization of response, resulting in increased exacerbations and rare cases of death. The hypothesis examined in the present article is that, while single dosing with a beta-blocker may cause acute bronchoconstriction, chronic dosing may afford putative beneficial effects including attenuated airway hyperresponsiveness.
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90
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Curran DR, Cohn L. Advances in mucous cell metaplasia: a plug for mucus as a therapeutic focus in chronic airway disease. Am J Respir Cell Mol Biol 2009; 42:268-75. [PMID: 19520914 DOI: 10.1165/rcmb.2009-0151tr] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Mucous cell metaplasia is induced in response to harmful insults and provides front-line protection to clear the airway of toxic substances and cellular debris. In chronic airway diseases mucous metaplasia persists and results in airway obstruction and contributes significantly to morbidity and mortality. Mucus hypersecretion involves increased expression of mucin genes, and increased mucin production and release. The past decade has seen significant advances in our understanding of the molecular mechanisms by which these events occur. Inflammation stimulates epidermal growth factor receptor activation and IL-13 to induce both Clara and ciliated cells to transition into goblet cells through the coordinated actions of FoxA2, TTF-1, SPDEF, and GABA(A)R. Ultimately, these steps lead to up-regulation of MUC5AC expression, and increased mucin in goblet cell granules that fuse to the plasma membrane through actions of MARCKS, SNAREs, and Munc proteins. Blockade of mucus in exacerbations of asthma and chronic obstructive pulmonary disease may affect morbidity. Development of new therapies to target mucus production and secretion are now possible given the advances in our understanding of molecular mechanisms of mucous metaplasia. We now have a greater incentive to focus on inhibition of mucus as a therapy for chronic airway diseases.
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Affiliation(s)
- David R Curran
- Section of Pulmonary and Critical Care, Yale University School of Medicine, New Haven, CT 06520, USA
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Agonizing over agonism: should asthmatics turn their beta-receptors on or off? Proc Natl Acad Sci U S A 2009; 106:2095-6. [PMID: 19211783 DOI: 10.1073/pnas.0812935106] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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