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Sharma P, Penn RB. Can GPCRs Be Targeted to Control Inflammation in Asthma? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1304:1-20. [PMID: 34019260 DOI: 10.1007/978-3-030-68748-9_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Historically, the drugs used to manage obstructive lung diseases (OLDs), asthma, and chronic obstructive pulmonary disease (COPD) either (1) directly regulate airway contraction by blocking or relaxing airway smooth muscle (ASM) contraction or (2) indirectly regulate ASM contraction by inhibiting the principal cause of ASM contraction/bronchoconstriction and airway inflammation. To date, these tasks have been respectively assigned to two diverse drug types: agonists/antagonists of G protein-coupled receptors (GPCRs) and inhaled or systemic steroids. These two types of drugs "stay in their lane" with respect to their actions and consequently require the addition of the other drug to effectively manage both inflammation and bronchoconstriction in OLDs. Indeed, it has been speculated that safety issues historically associated with beta-agonist use (beta-agonists activate the beta-2-adrenoceptor (β2AR) on airway smooth muscle (ASM) to provide bronchoprotection/bronchorelaxation) are a function of pro-inflammatory actions of β2AR agonism. Recently, however, previously unappreciated roles of various GPCRs on ASM contractility and on airway inflammation have been elucidated, raising the possibility that novel GPCR ligands targeting these GPCRs can be developed as anti-inflammatory therapeutics. Moreover, we now know that many GPCRs can be "tuned" and not just turned "off" or "on" to specifically activate the beneficial therapeutic signaling a receptor can transduce while avoiding detrimental signaling. Thus, the fledging field of biased agonism pharmacology has the potential to turn the β2AR into an anti-inflammatory facilitator in asthma, possibly reducing or eliminating the need for steroids.
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Affiliation(s)
- Pawan Sharma
- Center for Translational Medicine, Division of Pulmonary, Allergy, & Critical Care Medicine Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College Thomas Jefferson University, Philadelphia, PA, USA
| | - Raymond B Penn
- Center for Translational Medicine, Division of Pulmonary, Allergy, & Critical Care Medicine Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College Thomas Jefferson University, Philadelphia, PA, USA.
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2
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Michel MC, Michel-Reher MB, Hein P. A Systematic Review of Inverse Agonism at Adrenoceptor Subtypes. Cells 2020; 9:E1923. [PMID: 32825009 PMCID: PMC7564766 DOI: 10.3390/cells9091923] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022] Open
Abstract
As many, if not most, ligands at G protein-coupled receptor antagonists are inverse agonists, we systematically reviewed inverse agonism at the nine adrenoceptor subtypes. Except for β3-adrenoceptors, inverse agonism has been reported for each of the adrenoceptor subtypes, most often for β2-adrenoceptors, including endogenously expressed receptors in human tissues. As with other receptors, the detection and degree of inverse agonism depend on the cells and tissues under investigation, i.e., they are greatest when the model has a high intrinsic tone/constitutive activity for the response being studied. Accordingly, they may differ between parts of a tissue, for instance, atria vs. ventricles of the heart, and within a cell type, between cellular responses. The basal tone of endogenously expressed receptors is often low, leading to less consistent detection and a lesser extent of observed inverse agonism. Extent inverse agonism depends on specific molecular properties of a compound, but inverse agonism appears to be more common in certain chemical classes. While inverse agonism is a fascinating facet in attempts to mechanistically understand observed drug effects, we are skeptical whether an a priori definition of the extent of inverse agonism in the target product profile of a developmental candidate is a meaningful option in drug discovery and development.
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Affiliation(s)
- Martin C. Michel
- Department of Pharmacology, Johannes Gutenberg University, 55131 Mainz, Germany;
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3
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Roach KM, Bradding P. Ca 2+ signalling in fibroblasts and the therapeutic potential of K Ca3.1 channel blockers in fibrotic diseases. Br J Pharmacol 2020; 177:1003-1024. [PMID: 31758702 DOI: 10.1111/bph.14939] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
The role of Ca2+ signalling in fibroblasts is of great interest in fibrosis-related diseases. Intracellular free Ca2+ ([Ca2+ ]i ) is a ubiquitous secondary messenger, regulating a number of cellular functions such as secretion, metabolism, differentiation, proliferation and contraction. The intermediate conductance Ca2+ -activated K+ channel KCa 3.1 is pivotal in Ca2+ signalling and plays a central role in fibroblast processes including cell activation, migration and proliferation through the regulation of cell membrane potential. Evidence from a number of approaches demonstrates that KCa 3.1 plays an important role in the development of many fibrotic diseases, including idiopathic pulmonary, renal tubulointerstitial fibrosis and cardiovascular disease. The KCa 3.1 selective blocker senicapoc was well tolerated in clinical trials for sickle cell disease, raising the possibility of rapid translation to the clinic for people suffering from pathological fibrosis. This review after analysing all the data, concludes that targeting KCa 3.1 should be a high priority for human fibrotic disease.
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Affiliation(s)
- Katy M Roach
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Peter Bradding
- Institute for Lung Health, Department of Respiratory Sciences, University of Leicester, Leicester, UK
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Role of cardiac mast cells in exercise training-mediated cardiac remodeling in angiotensin II-infused ovariectomized rats. Life Sci 2019; 219:209-218. [PMID: 30658099 DOI: 10.1016/j.lfs.2019.01.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/03/2019] [Accepted: 01/13/2019] [Indexed: 01/03/2023]
Abstract
AIMS Regular exercise is recommended in postmenopausal women to prevent the development of heart disease, but mechanism underlying the protection is not completely understood. Many studies have suggested that exercise training notably mediated whole body immune and inflammatory functions. Whether exercise training prevents cardiac dysfunction after deprivation of female sex hormones by inhibiting cardiac immune activation is therefore interesting. MAIN METHODS Nine-week treadmill running program was introduced in sham-operated and ovariectomized rats. In addition, chronic angiotensin II infusion was further challenged to activate pathological cardiac remodeling. Cardiac remodeling in associated with the density and degranulation of cardiac mast cells was then evaluated. KEY FINDINGS With exogenous angiotensin II-induced hypertension, cardiac hypertrophy with myocardial fibrosis was shown similarly in both sham-operated controls and ovariectomized rats. Although exercise training did not prevent cardiac hypertrophy, myocardial fibrosis was abolished by exercise. While ovariectomy increased both cardiac mast cell density and degranulation percentage, angiotensin II infusion only enhanced mast cell density. Exercise training could not decrease the density of mast cells, but it did normalize the percentage of degranulation in all groups. Correlation analysis suggested that cardiac mast cell activation is inversely associated with cardiomyocyte hypertrophy due to exercise training but is directly correlated to cardiac hypertrophy by angiotensin II infusion. SIGNIFICANCE Exercise training could attenuate cardiac mast cell hyperactivation induced by either deprivation of female sex hormones or excessive angiotensin II. Additionally, cardiac mast cells could be a solution in the distinction between physiological and pathological hypertrophic development.
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Chen Y, Kuang D, Zhao X, Chen D, Wang X, Yang Q, Wan J, Zhu Y, Wang Y, Zhang S, Wang Y, Tang Q, Masuzawa M, Wang G, Duan Y. miR-497-5p inhibits cell proliferation and invasion by targeting KCa3.1 in angiosarcoma. Oncotarget 2018; 7:58148-58161. [PMID: 27531900 PMCID: PMC5295420 DOI: 10.18632/oncotarget.11252] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 07/26/2016] [Indexed: 11/25/2022] Open
Abstract
Angiosarcoma is a rare malignant mesenchymal tumor with poor prognosis. We aimed to identify malignancy-associated miRNAs and their target genes, and explore biological functions of miRNA and its target in angiosarcoma. By miRNA microarrays and reverse transcription polymerase chain reaction, we identified 1 up-regulated miRNA (miR-222-3p) and 3 down-regulated miRNAs (miR-497-5p, miR-378-3p and miR-483-5p) in human angiosarcomas compared with human capillary hemangiomas. The intermediate-conductance calcium activated potassium channel KCa3.1 was one of the putative target genes of miR-497-5p, and marked up-regulation of KCa3.1 was detected in angiosarcoma biopsy specimens by immunohistochemistry. The inverse correlation of miR-497-5p and KCa3.1 also was observed in the ISO-HAS angiosarcoma cell line at the mRNA and protein levels. The direct targeting of KCa3.1 by miR-497-5p was evidenced by reduced luciferase activity due to complementary binding of miR-497-5p to KCa3.1 mRNA 3′ untranslated region. For the functional role of miR-497-5p/KCa3.1 pair, we showed that application of TRAM-34, a specific KCa3.1 channel blocker, or transfection of ISO-HAS cells with KCa3.1 siRNA or miR-497-5p mimics inhibited cell proliferation, cell cycle progression, and invasion by down-regulating cell-cycle related proteins including cyclin D1, surviving and P53 and down-regulating matrix metallopeptidase 9. In an in vivo angiosarcoma xenograft model, TRAM-34 or miR-497-5p mimics both inhibited tumor growth. In conclusion, the tumor suppressor miR-497-5p down-regulates KCa3.1 expression and contributes to the inhibition of angiosarcoma malignancy development. The miR-497-5p or KCa3.1 might be potential new targets for angiosarcoma treatment.
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Affiliation(s)
- Yaobing Chen
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dong Kuang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xia Zhao
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dong Chen
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoyan Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qin Yang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jie Wan
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yuanli Zhu
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yu Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shiying Zhang
- Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ying Wang
- Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qiang Tang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mikio Masuzawa
- Department of Regulation Biochemistry, Kitasato University School of Allied Health Sciences, Minamiku, Sagamihara Kanagawa, 252-0329, Japan
| | - Guoping Wang
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yaqi Duan
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Pathology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Ozkan MH, Uma S. β-adrenergic Receptor Blocker ICI 118,551 Selectively Increases Intermediate-Conductance Calcium-Activated Potassium Channel (IKCa
)-Mediated Relaxations in Rat Main Mesenteric Artery. Basic Clin Pharmacol Toxicol 2018; 122:570-576. [DOI: 10.1111/bcpt.12949] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 12/07/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Melike Hacer Ozkan
- Department of Pharmacology; Faculty of Pharmacy; Hacettepe University; Ankara Turkey
| | - Serdar Uma
- Department of Pharmacology; Faculty of Pharmacy; Hacettepe University; Ankara Turkey
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Abstract
β2-adrenoceptor agonists, often used in combination with corticosteroids, have been extensively used for the treatment of asthma. However, concerns have been raised regarding their adverse effects and safety including poor asthma control, life-threatening exacerbations, exacerbations that often require hospitalization, and asthma-related deaths. The question as to whether these adverse effects relate to the loss of their bronchoprotective action remains an interesting possibility. In the chapter, we will review the experimental evidence that describes the different potential factors and associated mechanisms that can blunt the therapeutic action of β2-adrenoceptor agonists in asthma. We show here evidence that various key inflammatory cytokines, growth factors, some respiratory viruses, certain allergens, unknown factors present in serum from atopic asthmatics have the capacity to impair β2-adrenoceptor function in airway smooth muscle, the main target of these drugs. More importantly, we present our latest research describing the role played by mast cells in impairing β2-adrenoceptor function. Although no definitive conclusion could be made regarding the implication of one single mechanism, receptor uncoupling, or receptor desensitization due to phosphorylation represents the main inhibitory pathways associated with a loss of β2-adrenoceptor function in airway smooth muscle. Targeting the pathways leading to β2-adrenoceptor dysfunction will likely provide novel therapies to improve the efficacy of β2-agonists in asthma.
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8
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Abstract
Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.
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Affiliation(s)
- P Bradding
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, UK
| | - G Arthur
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, UK
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9
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Chachi L, Gavrila A, Tliba O, Amrani Y. Abnormal corticosteroid signalling in airway smooth muscle: mechanisms and perspectives for the treatment of severe asthma. Clin Exp Allergy 2016; 45:1637-46. [PMID: 26017278 DOI: 10.1111/cea.12577] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Growing in vivo evidence supports the concept that airway smooth muscle produces various immunomodulatory factors that could contribute to asthma pathogenesis via the regulation of airway inflammation, airway narrowing and remodelling. Targeting ASM using bronchial thermoplasty has provided undeniable clinical benefits for patients with uncontrolled severe asthma who are refractory to glucocorticoid therapy. The present review will explain why the failure of glucocorticoids to adequately manage patients with severe asthma could derive from their inability to affect the immunomodulatory potential of ASM. We will support the view that ASM sensitivity to glucocorticoid therapy can be blunted in severe asthma and will describe some of the factors and mechanisms that could be responsible for glucocorticoid insensitivity.
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Affiliation(s)
- L Chachi
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - A Gavrila
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - O Tliba
- Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson School of Pharmacy, Philadelphia, PA, USA
| | - Y Amrani
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
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10
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Arthur GK, Duffy SM, Roach KM, Hirst RA, Shikotra A, Gaillard EA, Bradding P. KCa3.1 K+ Channel Expression and Function in Human Bronchial Epithelial Cells. PLoS One 2015; 10:e0145259. [PMID: 26689552 PMCID: PMC4687003 DOI: 10.1371/journal.pone.0145259] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/30/2015] [Indexed: 12/13/2022] Open
Abstract
The KCa3.1 K+ channel has been proposed as a novel target for pulmonary diseases such as asthma and pulmonary fibrosis. It is expressed in epithelia but its expression and function in primary human bronchial epithelial cells (HBECs) has not been described. Due to its proposed roles in the regulation of cell proliferation, migration, and epithelial fluid secretion, inhibiting this channel might have either beneficial or adverse effects on HBEC function. The aim of this study was to assess whether primary HBECs express the KCa3.1 channel and its role in HBEC function. Primary HBECs from the airways of healthy and asthmatic subjects, SV-transformed BEAS-2B cells and the neoplastic H292 epithelial cell line were studied. Primary HBECs, BEAS-2B and H292 cells expressed KCa3.1 mRNA and protein, and robust KCa3.1 ion currents. KCa3.1 protein expression was increased in asthmatic compared to healthy airway epithelium in situ, and KCa3.1 currents were larger in asthmatic compared to healthy HBECs cultured in vitro. Selective KCa3.1 blockers (TRAM-34, ICA-17043) had no effect on epithelial cell proliferation, wound closure, ciliary beat frequency, or mucus secretion. However, several features of TGFβ1-dependent epithelial-mesenchymal transition (EMT) were inhibited by KCa3.1 blockade. Treatment with KCa3.1 blockers is likely to be safe with respect to airway epithelial biology, and may potentially inhibit airway remodelling through the inhibition of EMT.
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Affiliation(s)
- Greer K. Arthur
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
- * E-mail:
| | - S. Mark Duffy
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
| | - Katy M. Roach
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
| | - Rob A. Hirst
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
| | - Aarti Shikotra
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
| | - Erol A. Gaillard
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
| | - Peter Bradding
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
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11
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Orai/CRACM1 and KCa3.1 ion channels interact in the human lung mast cell plasma membrane. Cell Commun Signal 2015; 13:32. [PMID: 26177720 PMCID: PMC4504158 DOI: 10.1186/s12964-015-0112-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 07/09/2015] [Indexed: 11/23/2022] Open
Abstract
Background Orai/CRACM1 ion channels provide the major Ca2+ influx pathway for FcεRI-dependent human lung mast cell (HLMC) mediator release. The Ca2+-activated K+ channel KCa3.1 modulates Ca2+ influx and the secretory response through hyperpolarisation of the plasma membrane. We hypothesised that there is a close functional and spatiotemporal interaction between these Ca2+- and K+-selective channels. Results Activation of FcεRI-dependent HLMC KCa3.1 currents was dependent on the presence of extracellular Ca2+, and attenuated in the presence of the selective Orai blocker GSK-7975A. Currents elicited by the KCa3.1 opener 1-EBIO were also attenuated by GSK-7975A. The Orai1 E106Q dominant-negative mutant ablated 1-EBIO and FcεRI-dependent KCa3.1 currents in HLMCs. Orai1 but not Orai2 was shown to co-immunoprecipitate with KCa3.1 when overexpressed in HEK293 cells, and Orai1 and KCa3.1 were seen to co-localise in the HEK293 plasma membrane using confocal microscopy. Conclusion KCa3.1 activation in HLMCs is highly dependent on Ca2+ influx through Orai1 channels, mediated via a close spatiotemporal interaction between the two channels.
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12
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Forsythe P. Microbes taming mast cells: Implications for allergic inflammation and beyond. Eur J Pharmacol 2015; 778:169-75. [PMID: 26130124 DOI: 10.1016/j.ejphar.2015.06.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/21/2015] [Accepted: 06/17/2015] [Indexed: 12/30/2022]
Abstract
There is increasing awareness of a relationship between our microbiota and the pathogenesis of allergy and other inflammatory diseases. In investigating the mechanisms underlying microbiota modulation of allergy the focus has been on the induction phase; alterations in the phenotype and function of antigen presenting cells, induction of regulatory T cells and shifts in Th1/Th2 balance. However there is evidence that microbes can influence the effector phase of disease, specifically that certain potentially beneficial bacteria can attenuate mast cell activation and degranulation. Furthermore, it appears that different non-pathogenic bacteria can utilize distinct mechanisms to stabilize mast cells, acting locally though direct interaction with the mast cell at mucosal sites or attenuating systemic mast cell dependent responses, likely through indirect signaling mechanisms. The position of mast cells on the frontline of defense against pathogens also suggests they may play an important role in fostering the host-microbiota relationship. Mast cells are also conduits of neuro-immuo-endocrine communication, suggesting the ability of microbes to modulate cell responses may have implications for host physiology beyond immunology. Further investigation of mast cell regulation by non-pathogenic or symbiotic bacteria will likely lead to a greater understanding of host microbiota interaction and the role of the microbiome in health and disease.
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Affiliation(s)
- Paul Forsythe
- McMaster Brain-Body Institute at St. Joseph's Healthcare, Hamilton, The Firestone Institute for Respiratory Health and Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
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13
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Ramamoorthi R, Graef KM, Krattiger A, Dent JC. WIPO Re:Search: Catalyzing Collaborations to Accelerate Product Development for Diseases of Poverty. Chem Rev 2014; 114:11272-9. [DOI: 10.1021/cr5000656] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Roopa Ramamoorthi
- BIO Ventures for Global Health, 401 Terry Avenue North, Seattle, Washington 98109, United States
| | - Katy M. Graef
- BIO Ventures for Global Health, 401 Terry Avenue North, Seattle, Washington 98109, United States
| | - Anatole Krattiger
- World Intellectual Property Organization, 34, Chemin des Colombettes, CH-1211 Geneva 20, Switzerland
| | - Jennifer C. Dent
- BIO Ventures for Global Health, 401 Terry Avenue North, Seattle, Washington 98109, United States
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14
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Bellinger DL, Lorton D. Autonomic regulation of cellular immune function. Auton Neurosci 2014; 182:15-41. [PMID: 24685093 DOI: 10.1016/j.autneu.2014.01.006] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/17/2014] [Indexed: 12/21/2022]
Abstract
The nervous system and the immune system (IS) are two integrative systems that work together to detect threats and provide host defense, and to maintain/restore homeostasis. Cross-talk between the nervous system and the IS is vital for health and well-being. One of the major neural pathways responsible for regulating host defense against injury and foreign antigens and pathogens is the sympathetic nervous system (SNS). Stimulation of adrenergic receptors (ARs) on immune cells regulates immune cell development, survival, proliferative capacity, circulation, trafficking for immune surveillance and recruitment, and directs the cell surface expression of molecules and cytokine production important for cell-to-cell interactions necessary for a coordinated immune response. Finally, AR stimulation of effector immune cells regulates the activational state of immune cells and modulates their functional capacity. This review focuses on our current understanding of the role of the SNS in regulating host defense and immune homeostasis. SNS regulation of IS functioning is a critical link to the development and exacerbation of chronic immune-mediated diseases. However, there are many mechanisms that need to be further unraveled in order to develop sound treatment strategies that act on neural-immune interaction to resolve or prevent chronic inflammatory diseases, and to improve health and quality of life.
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Affiliation(s)
- Denise L Bellinger
- Department of Pathology and Human Anatomy, Loma Linda University, School of Medicine, Loma Linda, CA, 92350, USA.
| | - Dianne Lorton
- College of Arts and Sciences, Kent State University and the Kent Summa Initiative for Clinical and Translational Research, Summa Health System, Akron, OH 44304, USA
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15
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Yang W, Schmid E, Nurbaeva MK, Szteyn K, Leibrock C, Yan J, Schaller M, Gulbins E, Shumilina E, Lang F. Role of acid sphingomyelinase in the regulation of mast cell function. Clin Exp Allergy 2013; 44:79-90. [DOI: 10.1111/cea.12229] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 10/14/2013] [Accepted: 10/23/2013] [Indexed: 12/11/2022]
Affiliation(s)
- W. Yang
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - E. Schmid
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - M. K. Nurbaeva
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - K. Szteyn
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - C. Leibrock
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - J. Yan
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - M. Schaller
- Department of Dermatology; University of Tübingen; Tübingen Germany
| | - E. Gulbins
- Institute of Molecular Biology; University of Duisburg-Essen; Essen Germany
| | - E. Shumilina
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - F. Lang
- Department of Physiology; University of Tübingen; Tübingen Germany
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16
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Ashmole I, Bradding P. Ion channels regulating mast cell biology. Clin Exp Allergy 2013; 43:491-502. [PMID: 23600539 DOI: 10.1111/cea.12043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/06/2012] [Accepted: 08/28/2012] [Indexed: 11/28/2022]
Abstract
Mast cells play a central role in the pathophysiology of asthma and related allergic conditions. Mast cell activation leads to the degranulation of preformed mediators such as histamine and the secretion of newly synthesised proinflammatory mediators such as leukotrienes and cytokines. Excess release of these mediators contributes to allergic disease states. An influx of extracellular Ca2+ is essential for mast cell mediator release. From the Ca2+ channels that mediate this influx, to the K+ , Cl- and transient receptor potential channels that set the cell membrane potential and regulate Ca2+ influx, ion channels play a critical role in mast cell biology. In this review we provide an overview of our current knowledge of ion channel expression and function in mast cells with an emphasis on how channels interact to regulate Ca2+ signalling.
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Affiliation(s)
- I Ashmole
- Department of Infection, Immunity and Inflammation, Institute for Lung Heath, Glenfield Hospital, University of Leicester, Leicester, LE3 9QP, UK
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Chachi L, Shikotra A, Duffy SM, Tliba O, Brightling C, Bradding P, Amrani Y. Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells. THE JOURNAL OF IMMUNOLOGY 2013; 191:2624-2636. [PMID: 23904164 DOI: 10.4049/jimmunol.1300104] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Identifying the factors responsible for relative glucocorticosteroid (GC) resistance present in patients with severe asthma and finding tools to reverse it are of paramount importance. In asthma we see in vivo evidence of GC-resistant pathways in airway smooth muscle (ASM) bundles that can be modeled in vitro by exposing cultured ASM cells to TNF-α/IFN-γ. This action drives GC insensitivity via protein phosphatase 5-dependent impairment of GC receptor phosphorylation. In this study, we investigated whether KCa3.1 ion channels modulate the activity of GC-resistant pathways using our ASM model of GC insensitivity. Immunohistochemical staining of endobronchial biopsies revealed that KCa3.1 channels are localized to the plasma membrane and nucleus of ASM in both healthy controls and asthmatic patients, irrespective of disease severity. Western blot assays and immunofluorescence staining confirmed the nuclear localization of KCa3.1 channels in ASM cells. The functional importance of KCa3.1 channels in the regulation of GC-resistant chemokines induced by TNF-α/IFN-γ was assessed using complementary inhibitory strategies, including KCa3.1 blockers (TRAM-34 and ICA-17043) or KCa3.1-specific small hairpin RNA delivered by adenoviruses. KCa3.1 channel blockade led to a significant reduction of fluticasone-resistant CX3CL1, CCL5, and CCL11 gene and protein expression. KCa3.1 channel blockade also restored fluticasone-induced GC receptor-α phosphorylation at Ser(211) and transactivation properties via the suppression of cytokine-induced protein phosphatase 5 expression. The effect of KCa3.1 blockade was evident in ASM cells from both healthy controls and asthmatic subjects. In summary, KCa3.1 channels contribute to the regulation of GC-resistant inflammatory pathways in ASM cells: blocking KCa3.1 channels may enhance corticosteroid activity in severe asthma.
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Affiliation(s)
- Latifa Chachi
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, U.K
| | - Aarti Shikotra
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, U.K
| | - S Mark Duffy
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, U.K
| | - Omar Tliba
- Department of Pharmaceutical Sciences, Thomas Jefferson University, Jefferson School of Pharmacy, Philadelphia, PA, USA
| | - Christopher Brightling
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, U.K
| | - Peter Bradding
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, U.K
| | - Yassine Amrani
- Department of Infection, Immunity and Inflammation, University of Leicester, University Road, Leicester, LE1 7RH, U.K
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Kroigaard C, Dalsgaard T, Nielsen G, Laursen BE, Pilegaard H, Köhler R, Simonsen U. Activation of endothelial and epithelial K(Ca) 2.3 calcium-activated potassium channels by NS309 relaxes human small pulmonary arteries and bronchioles. Br J Pharmacol 2013; 167:37-47. [PMID: 22506557 DOI: 10.1111/j.1476-5381.2012.01986.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Small (K(Ca) 2) and intermediate (K(Ca) 3.1) conductance calcium-activated potassium channels (K(Ca) ) may contribute to both epithelium- and endothelium-dependent relaxations, but this has not been established in human pulmonary arteries and bronchioles. Therefore, we investigated the expression of K(Ca) 2.3 and K(Ca) 3.1 channels, and hypothesized that activation of these channels would produce relaxation of human bronchioles and pulmonary arteries. EXPERIMENTAL APPROACH Channel expression and functional studies were conducted in human isolated small pulmonary arteries and bronchioles. K(Ca) 2 and K(Ca) 3.1 currents were examined in human small airways epithelial (HSAEpi) cells by whole-cell patch clamp techniques. RESULTS While K(Ca) 2.3 expression was similar, K(Ca) 3.1 protein was more highly expressed in pulmonary arteries than bronchioles. Immunoreactive K(Ca) 2.3 and K(Ca) 3.1 proteins were found in both endothelium and epithelium. K(Ca) currents were present in HSAEpi cells and sensitive to the K(Ca) 2.3 blocker UCL1684 and the K(Ca) 3.1 blocker TRAM-34. In pulmonary arteries contracted by U46619 and in bronchioles contracted by histamine, the K(Ca) 2.3/ K(Ca) 3.1 activator, NS309, induced concentration-dependent relaxations. NS309 was equally potent in relaxing pulmonary arteries, but less potent in bronchioles, than salbutamol. NS309 relaxations were blocked by the K(Ca) 2 channel blocker apamin, while the K(Ca) 3.1 channel blocker, charybdotoxin failed to reduce relaxation to NS309 (0.01-1 µM). CONCLUSIONS AND IMPLICATIONS K(Ca) 2.3 and K(Ca) 3.1 channels are expressed in the endothelium of human pulmonary arteries and epithelium of bronchioles. K(Ca) 2.3 channels contributed to endo- and epithelium-dependent relaxations suggesting that these channels are potential targets for treatment of pulmonary hypertension and chronic obstructive pulmonary disease.
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Affiliation(s)
- Christel Kroigaard
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Faculty of Health Sciences, Aarhus University, Aarhus C, Denmark
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Forsythe P, Wang B, Khambati I, Kunze WA. Systemic effects of ingested Lactobacillus rhamnosus: inhibition of mast cell membrane potassium (IKCa) current and degranulation. PLoS One 2012; 7:e41234. [PMID: 22815978 PMCID: PMC3398942 DOI: 10.1371/journal.pone.0041234] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 06/19/2012] [Indexed: 12/14/2022] Open
Abstract
Exposure of the intestine to certain strains lactobacillus can have systemic immune effects that include the attenuation of allergic responses. Despite the central role of mast cells in allergic disease little is known about the effect of lactobacilli on the function of these cells. To address this we assessed changes in rat mast cell activation following oral treatment with a strain of Lactobacillus known to attenuate allergic responses in animal models. Sprague Dawley rats were fed with L. rhamnosus JB-1 (1×10(9)) or vehicle control for 9 days. Mediator release from peritoneal mast cells (RPMC) was determined in response to a range of stimuli. Passive cutaneous anaphylaxis (PCA) was used to assess mast cell responses in vivo. The Ca(2+) activated K(+) channel (KCa3.1) current, identified as critical to mast cell degranulation, was monitored by whole cell patch-clamp. L. rhamnosus JB-1 treatment lead to significant inhibition of mast cell mediator release in response to a range of stimuli including IgE mediated activation. Furthermore, the PCA response was significantly reduced in treated rats. Patch-clamp studies revealed that RPMC from treated animals were much less responsive to the KCa3.1 opener, DCEBIO. These studies demonstrate that Ingestion of L. rhamnosus JB-1 leads to mast cell stabilization in rats and identify KCa3.1 as an immunomodulatory target for certain lactobacilli. Thus the systemic effects of certain candidate probiotics may include mast cell stabilization and such actions could contribute to the beneficial effect of these organisms in allergic and other inflammatory disorders.
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Affiliation(s)
- Paul Forsythe
- Brain-Body Institute, McMaster University, Hamilton, Ontario, Canada.
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Wulff H, Castle NA. Therapeutic potential of KCa3.1 blockers: recent advances and promising trends. Expert Rev Clin Pharmacol 2012; 3:385-96. [PMID: 22111618 DOI: 10.1586/ecp.10.11] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Ca(2+)-activated K(+) channel K(Ca)3.1 regulates membrane potential and calcium signaling in erythrocytes, activated T and B cells, macrophages, microglia, vascular endothelium, epithelia, and proliferating vascular smooth muscle cells and fibroblasts. K(Ca)3.1 has therefore been suggested as a potential therapeutic target for diseases such as sickle cell anemia, asthma, coronary restenosis after angioplasty, atherosclerosis, kidney fibrosis and autoimmunity, where activation and excessive proliferation of one or more of these cell types is involved in the pathology. This article will review the physiology and pharmacology of K(Ca)3.1 and critically examine the available preclinical and clinical data validating K(Ca)3.1 as a therapeutic target.
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Serum- and glucocorticoid-inducible kinase 1 in the regulation of renal and extrarenal potassium transport. Clin Exp Nephrol 2011; 16:73-80. [DOI: 10.1007/s10157-011-0488-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 04/08/2010] [Indexed: 01/24/2023]
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Law J, Yeung C, Wan S, Ingebrandt S, Lau H, Rudd J, Chan M. The significance of chloride in the inhibitory action of disodium cromoglycate on immunologically-stimulated rat peritoneal mast cells. Biochim Biophys Acta Gen Subj 2011; 1810:867-74. [DOI: 10.1016/j.bbagen.2011.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 05/09/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022]
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Cruse G, Singh SR, Duffy SM, Doe C, Saunders R, Brightling CE, Bradding P. Functional KCa3.1 K+ channels are required for human fibrocyte migration. J Allergy Clin Immunol 2011; 128:1303-1309.e2. [PMID: 21872912 PMCID: PMC3526791 DOI: 10.1016/j.jaci.2011.07.047] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 07/05/2011] [Accepted: 07/25/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND Fibrocytes are bone marrow-derived CD34(+) collagen I-positive cells present in peripheral blood that develop α-smooth muscle actin expression and contractile activity in tissue culture. They are implicated in the pathogenesis of tissue remodeling and fibrosis in both patients with asthma and those with idiopathic pulmonary fibrosis. Targeting fibrocyte migration might therefore offer a new approach for the treatment of these diseases. Ion channels play key roles in cell function, but the ion-channel repertoire of human fibrocytes is unknown. OBJECTIVE We sought to examine whether human fibrocytes express the K(Ca)3.1 K(+) channel and to determine its role in cell differentiation, survival, and migration. METHODS Fibrocytes were cultured from the peripheral blood of healthy subjects and patients with asthma. Whole-cell patch-clamp electrophysiology was used for the measurement of ion currents, whereas mRNA and protein were examined to confirm channel expression. Fibrocyte migration and proliferation assays were performed in the presence of K(Ca)3.1 ion-channel blockers. RESULTS Human fibrocytes cultured from the peripheral blood of both healthy control subjects and asthmatic patients expressed robust K(Ca)3.1 ion currents together with K(Ca)3.1 mRNA and protein. Two specific and distinct K(Ca)3.1 blockers (TRAM-34 and ICA-17043) markedly inhibited fibrocyte migration in transwell migration assays. Channel blockers had no effect on fibrocyte growth, apoptosis, or differentiation in cell culture. CONCLUSIONS The K(+) channel K(Ca)3.1 plays a key role in human fibrocyte migration. Currently available K(Ca)3.1-channel blockers might therefore attenuate tissue fibrosis and remodeling in patients with diseases such as idiopathic pulmonary fibrosis and asthma through the inhibition of fibrocyte recruitment.
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Affiliation(s)
- Glenn Cruse
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
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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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Dalsgaard T, Kroigaard C, Simonsen U. Calcium-activated potassium channels - a therapeutic target for modulating nitric oxide in cardiovascular disease? Expert Opin Ther Targets 2010; 14:825-37. [PMID: 20560781 DOI: 10.1517/14728222.2010.500616] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Cardiovascular risk factors are often associated with endothelial dysfunction, which is also prognostic for occurrence of cardiovascular events. Endothelial dysfunction is reflected by blunted vasodilatation and reduced nitric oxide (NO) bioavailability. Endothelium-dependent vasodilatation is mediated by NO, prostacyclin, and an endothelium-derived hyperpolarising factor (EDHF), and involves small (SK) and intermediate (IK) conductance Ca(2+)-activated K(+) channels. Therefore, SK and IK channels may be drug targets for the treatment of endothelial dysfunction in cardiovascular disease. AREAS COVERED IN THIS REVIEW SK and IK channels are involved in EDHF-type vasodilatation, but recent studies suggest that these channels are also involved in the regulation of NO bioavailability. Here we review how SK and IK channels may regulate NO bioavailability. WHAT THE READER WILL GAIN Opening of SK and IK channels is associated with EDHF-type vasodilatation, but, through increased endothelial cell Ca(2+) influx, L-arginine uptake, and decreased ROS production, it may also lead to increased NO bioavailability and endothelium-dependent vasodilatation. TAKE HOME MESSAGE Opening of SK and IK channels can increase both EDHF and NO-mediated vasodilatation. Therefore, openers of SK and IK channels may have the potential of improving endothelial cell function in cardiovascular disease.
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Affiliation(s)
- Thomas Dalsgaard
- Department of Pharmacology, Aarhus University, DK-8000 Aarhus C, Denmark.
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Zemtsova IM, Heise N, Fröhlich H, Qadri SM, Kucherenko Y, Boini KM, Pearce D, Shumilina E, Lang F. Blunted IgE-mediated activation of mast cells in mice lacking the serum- and glucocorticoid-inducible kinase SGK3. Am J Physiol Cell Physiol 2010; 299:C1007-14. [PMID: 20686074 DOI: 10.1152/ajpcell.00539.2009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that pharmacological inhibition of the phosphoinositol-3 (PI3) kinase disrupts the activation of mast cells. Through phosphoinositide-dependent kinase PDK1, PI3 kinase activates the serum- and glucocorticoid-inducible kinase 3 (SGK3). The present study explored the role of SGK3 in mast cell function. Mast cells were isolated and cultured from bone marrow (BMMCs) of gene-targeted mice lacking SGK3 (sgk3(-/-)) and their wild-type littermates (sgk3(+/+)). BMMC numbers in the ear conch were similar in both genotypes. Stimulation with IgE and cognate antigen triggered the release of intracellular Ca(2+) and entry of extracellular Ca(2+). Influx of extracellular Ca(2+) but not Ca(2+) release from intracellular stores was significantly blunted in sgk3(-/-) BMMCs compared with sgk3(+/+) BMMCs. Antigen stimulation further led to a rapid increase of a K(+)-selective conductance in sgk3(+/+) BMMCs, an effect again blunted in sgk3(-/-) BMMCs. In contrast, the Ca(2+) ionophore ionomycin activated K(+) currents to a similar extent in sgk3(-/-) and in sgk3(+/+) BMMCs. β-Hexosaminidase release, triggered by antigen stimulation, was also significantly decreased in sgk3(-/-) BMMCs. IgE-dependent anaphylaxis measured as a sharp decrease in body temperature upon injection of DNP-HSA antigen was again significantly blunted in sgk3(-/-) compared with sgk3(+/+) mice. Serum histamine levels measured 30 min after induction of an anaphylactic reaction were significantly lower in sgk3(-/-) than in sgk3(+/+) mice. In conclusion, both in vitro and in vivo function of BMMCs are impaired in gene targeted mice lacking SGK3. Thus SGK3 is critical for proper mast cell function.
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Affiliation(s)
- Irina M Zemtsova
- Department of Physiology, University of Tübingen, Tübingen, Germany
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28
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Cruse G, Yang W, Duffy SM, Chachi L, Leyland M, Amrani Y, Bradding P. Counterregulation of beta(2)-adrenoceptor function in human mast cells by stem cell factor. J Allergy Clin Immunol 2009; 125:257-63.e1-5. [PMID: 19864009 DOI: 10.1016/j.jaci.2009.08.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 07/10/2009] [Accepted: 08/05/2009] [Indexed: 02/01/2023]
Abstract
BACKGROUND Mast cells contribute to the pathophysiology of asthma with the sustained release of both preformed and newly generated mediators in response to allergens and other diverse stimuli. Stem cell factor (SCF) is the key human mast cell growth factor, but also primes mast cells for mediator release. SCF expression is markedly increased in asthmatic airways. Short-acting beta(2)-adrenoceptor drugs such as albuterol inhibit human lung mast cell (HLMC) degranulation in vitro in the absence of SCF, but their effect in the presence of SCF is not known. OBJECTIVE The aim of this study was to elucidate the effects of albuterol on HLMC function in the presence of SCF. METHODS Mediator release and K(Ca)3.1 ion channel activity were analyzed in purified HLMC. Intracellular signalling and beta(2)-adrenoceptor phosphorylation and internalization were analyzed in the HMC-1 human mast cell line. RESULTS beta(2)-Adrenoceptor agonist-dependent inhibition of K(Ca)3.1 ion channels and HLMC mediator release was markedly attenuated in the presence of SCF. Remarkably, albuterol actually potentiated IgE-induced histamine release in a dose-dependent manner when both SCF and IgE were present. These effects were related to the SCF-dependent phosphorylation of Tyr350 on the beta(2)-adrenoceptor with immediate uncoupling of the receptor followed by receptor internalization. CONCLUSION The potentially beneficial effects of beta(2)-adrenoceptor agonists in asthmatic airways may be blunted as a result of the high concentrations of SCF present.
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Affiliation(s)
- Glenn Cruse
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom.
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Sobiesiak M, Shumilina E, Lam RS, Wölbing F, Matzner N, Kaesler S, Zemtsova IM, Lupescu A, Zahir N, Kuhl D, Schaller M, Biedermann T, Lang F. Impaired Mast Cell Activation in Gene-Targeted Mice Lacking the Serum- and Glucocorticoid-Inducible Kinase SGK1. THE JOURNAL OF IMMUNOLOGY 2009; 183:4395-402. [DOI: 10.4049/jimmunol.0803017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Bradding P, Wulff H. The K+ channels K(Ca)3.1 and K(v)1.3 as novel targets for asthma therapy. Br J Pharmacol 2009; 157:1330-9. [PMID: 19681865 PMCID: PMC2765317 DOI: 10.1111/j.1476-5381.2009.00362.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 05/06/2009] [Accepted: 05/11/2009] [Indexed: 01/22/2023] Open
Abstract
Asthma affects 10% of the UK population and is an important cause of morbidity and mortality at all ages. Current treatments are either ineffective or carry unacceptable side effects for a number of patients; in consequence, development of new approaches to therapy are important. Ion channels are emerging as attractive therapeutic targets in a variety of non-excitable cells. Ion channels conducting K(+) modulate the activity of several structural and inflammatory cells which play important roles in the pathophysiology of asthma. Two channels of particular interest are the voltage-gated K(+) channel K(v)1.3 and the intermediate conductance Ca(2+)-activated K(+) channel K(Ca)3.1 (also known as IK(Ca)1 or SK4). K(v)1.3 is expressed in IFNgamma-producing T cells while K(Ca)3.1 is expressed in T cells, mast cells, macrophages, airway smooth muscle cells, fibroblasts and epithelial cells. Both channels play important roles in cell activation, migration, and proliferation through the regulation of membrane potential and calcium signalling. We hypothesize that K(Ca)3.1- and/or K(v)1.3-dependent cell processes are one of the common denominators in asthma pathophysiology. If true, these channels might serve as novel targets for the treatment of asthma. Emerging evidence lends support to this hypothesis. Further validation through the study of the role that these channels play in normal and asthmatic airway cell (patho)physiology and in vivo models will provide further justification for the assessment of small molecule blockers of K(v)1.3 and K(Ca)3.1 in the treatment of asthma.
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Affiliation(s)
- Peter Bradding
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, UK.
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Duffy SM, Cruse G, Cockerill SL, Brightling CE, Bradding P. Engagement of the EP2 prostanoid receptor closes the K+ channel KCa3.1 in human lung mast cells and attenuates their migration. Eur J Immunol 2008; 38:2548-56. [PMID: 18792407 PMCID: PMC2699428 DOI: 10.1002/eji.200738106] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human lung mast cells (HLMC) express the Ca(2+)-activated K(+) channel K(Ca)3.1, which plays a crucial role in their migration to a variety of diverse chemotactic stimuli. K(Ca)3.1 activation is attenuated by the beta(2)-adrenoceptor and the adenosine A(2A) receptor through a G(s)-coupled mechanism independent of cyclic AMP. Prostaglandin E(2) promotes degranulation and migration of mouse bone marrow-derived mast cells through the G(i)-coupled EP(3) prostanoid receptor, and induces LTC(4) and cytokine secretion from human cord blood-derived mast cells. However, PGE(2) binding to the G(s)-coupled EP(2) receptor on HLMC inhibits their degranulation. We show that EP(2) receptor engagement closes K(Ca)3.1 in HLMC. The EP(2) receptor-specific agonist butaprost was more potent than PGE(2) in this respect, and the effects of both agonists were reversed by the EP(2) receptor antagonist AH6809. Butaprost markedly inhibited HLMC migration induced by chemokine-rich airway smooth muscle-conditioned media. Interestingly, PGE(2) alone was chemotactic for HLMC at high concentrations (1 microM), but was a more potent chemoattractant for HLMC following EP(2) receptor blockade. Therefore, the G(s)-coupled EP(2) receptor closes K(Ca)3.1 in HLMC and attenuates both chemokine- and PGE(2)-dependent HLMC migration. EP(2) receptor agonists with K(Ca)3.1 modulating function may be useful for the treatment of mast cell-mediated disease.
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Affiliation(s)
- S Mark Duffy
- The Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, UK
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Role of Ca(2+) mobilization in desensitization of beta-adrenoceptors by platelet-derived growth factor in airway smooth muscle. Eur J Pharmacol 2008; 591:259-65. [PMID: 18611401 DOI: 10.1016/j.ejphar.2008.06.072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 06/13/2008] [Accepted: 06/22/2008] [Indexed: 11/20/2022]
Abstract
Platelet-derived growth factor (PDGF), which is released from eosinophils and fibroblasts, may be implicated in the pathophysiology of bronchial asthma. To examine the involvement of airway inflammation in beta-adrenergic desensitization, the present study was designed to determine whether pre-exposure to PDGF deteriorates beta-adrenoceptor function in airway smooth muscle. We focused on Ca(2+) signaling as an intracellular mechanism involved in this phenomenon. Isometric tension and F(340)/F(380) (an indicator of intracellular Ca(2+) concentration) induced by isoprenaline and other cAMP-related agents were simultaneously measured before and after exposure to PDGF in fura-2-loaded guinea-pig tracheal smooth muscle. Indomethacin was applied throughout the experiments to abolish prostaglandin synthesis by PDGF. After exposure of the tissues to 10 ng/ml PDGF for 15 min, the effects of isoprenaline, a beta-adrenoceptor agonist, and forskolin, a direct inhibitor of adenylyl cyclase, against methacholine-induced contraction were markedly reduced with increasing F(340)/F(380). However, in the presence of verapamil, an inhibitor of voltage-dependent Ca(2+) channels, the reduced responsiveness to isoprenaline and forskolin induced by pre-exposure to PDGF was reversed with reducing F(340)/F(380). Reduced responsiveness to isoprenaline by PDGF was also not observed in the presence of Ca(2+)-free solution. The inhibitory effects of db-cAMP, an analogue of cAMP, and theophylline, a nonselective inhibitor of phosphodiesterase, were not attenuated by PDGF. In conclusion, pre-exposure to PDGF causes impairment of the beta-adrenoceptors/adenylyl cyclase processes in airway smooth muscle that is independent of cyclooxygenase synthesis by PDGF. Ca(2+) mobilization by Ca(2+) influx through voltage-dependent Ca(2+) channels is involved in this heterologous desensitization of beta-adrenoceptors.
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Kobayashi M, Kume H, Oguma T, Makino Y, Ito Y, Shimokata K. Mast cell tryptase causes homologous desensitization of beta-adrenoceptors by Ca2+ sensitization in tracheal smooth muscle. Clin Exp Allergy 2007; 38:135-44. [PMID: 18028457 DOI: 10.1111/j.1365-2222.2007.02879.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Recent studies have revealed that in asthma, mast cells infiltrate to the smooth muscle layer and release tryptase, an enzymatic activator of protease-activated receptor 2 (PAR2). This phenomenon, mast cell myositis, is proposed as a new feature of asthma. However, little is known about the involvement of mast cell myositis in the pathophysiology of asthma. OBJECTIVE This study was designed to determine whether mast cell degranulation has any functional impact on beta-adrenoceptors via PAR2 in airway smooth muscle. Moreover, we focused on Ca(2+) signalling as a mechanism underlying alteration of smooth muscle tone and responsiveness. METHODS Isometric tension and F(340)/F(380), an indicator of the concentration of intracellular Ca(2+) ([Ca(2+)](i)), were simultaneously measured using fura-2-loaded tissues isolated from guinea-pig tracheal smooth muscle. RESULTS Tryptase (1-100 nm) caused tension with elevated F(340)/F(380), and after exposure to tryptase for 15 min the inhibitory effect of isoprenaline (ISO) against methacholine was attenuated without elevating F(340)/F(380) in a concentration-dependent manner. Tryptase (<1 nm) had a modest effect on tension, but prolonged treatment (</=120 min) with 0.1 nm tryptase also reduced the effects of ISO in a time-dependent manner. When tissues were incubated with tryptase in the presence of Y-27632, a Rho-kinase inhibitor, reduced responsiveness to ISO by tryptase was reversed without affecting F(340)/F(380). In contrast, pre-treatment with SKF96365, a non-selective inhibitor of Ca(2+) channels, did not antagonize the effect of tryptase. Moreover, pre-treatment with SLIGKV-NH(2), a non-enzymatic activator of PAR2, resulted in a loss of beta-adrenergic efficacy, similar to tryptase. The effect of cAMP-related agents bypassing beta-adrenoceptors was not attenuated after exposure to tryptase. CONCLUSION In mast cell myositis, tryptase released from mast cells acts on airway smooth muscle, leading to homologous beta-adrenergic desensitization mediated by [Ca(2+)](i)-independent mechanisms via PAR2 activation.
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Affiliation(s)
- M Kobayashi
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
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Wykes RCE, Lee M, Duffy SM, Yang W, Seward EP, Bradding P. Functional transient receptor potential melastatin 7 channels are critical for human mast cell survival. THE JOURNAL OF IMMUNOLOGY 2007; 179:4045-52. [PMID: 17785843 DOI: 10.4049/jimmunol.179.6.4045] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mast cells play a significant role in the pathophysiology of many diverse diseases such as asthma and pulmonary fibrosis. Ca2+ influx is essential for mast cell degranulation and release of proinflammatory mediators, while Mg2+ plays an important role in cellular homeostasis. The channels supporting divalent cation influx in human mast cells have not been identified, but candidate channels include the transient receptor potential melastatin (TRPM) family. In this study, we have investigated TRPM7 expression and function in primary human lung mast cells (HLMCs) and in the human mast cell lines LAD2 and HMC-1, using RT-PCR, patch clamp electrophysiology, and RNA interference. Whole cell voltage-clamp recordings revealed a nonselective cation current that activated spontaneously following loss of intracellular Mg2+. The current had a nonlinear current-voltage relationship with the characteristic steep outward rectification associated with TRPM7 channels. Reducing external divalent concentration from 3 to 0.3 mM dramatically increased the size of the outward current, whereas the current was markedly inhibited by elevated intracellular Mg2+ (6 mM). Ion substitution experiments revealed cation selectivity and Ca2+ permeability. RT-PCR confirmed the presence of mRNA for TRPM7 in HLMC, LAD2, and HMC-1 cells. Adenoviral-mediated knockdown of TRPM7 in HLMC with short hairpin RNA and in HMC-1 with short interfering RNA markedly reduced TRPM7 currents and induced cell death, an effect that was not rescued by raising extracellular Mg2+. In summary, HLMC and human mast cell lines express the nonselective cation channel TRPM7 whose presence is essential for cell survival.
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Affiliation(s)
- Rob C E Wykes
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom
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Duffy SM, Cruse G, Brightling CE, Bradding P. Adenosine closes the K+ channel KCa3.1 in human lung mast cells and inhibits their migration via the adenosine A2A receptor. Eur J Immunol 2007; 37:1653-62. [PMID: 17474152 PMCID: PMC2699420 DOI: 10.1002/eji.200637024] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Human lung mast cells (HLMC) express the Ca2+-activated K+ channel KCa3.1, which opens following IgE-dependent activation. This hyperpolarises the cell membrane and potentiates both Ca2+ influx and degranulation. In addition, blockade of KCa3.1 profoundly inhibits HLMC migration to a variety of diverse chemotactic stimuli. KCa3.1 activation is attenuated by the β2adrenoceptor through a Gαs-coupled mechanism independent of cyclic AMP. Adenosine is an important mediator that both attenuates and enhances HLMC mediator release through the Gαs-coupled A2A and A2B adenosine receptors, respectively. We show that at concentrations that inhibit HLMC degranulation (10–5–10–3 M), adenosine closes KCa3.1 both dose-dependently and reversibly. KCa3.1 suppression by adenosine was reversed partially by the selective adenosine A2A receptor antagonist ZM241385 but not by the A2B receptor antagonist MRS1754, and the effects of adenosine were mimicked by the selective A2A receptor agonist CGS21680. Adenosine also opened a depolarising current carried by non-selective cations. As predicted from the role of KCa3.1 in HLMC migration, adenosine abolished HLMC chemotaxis to asthmatic airway smooth muscle-conditioned medium. In summary, the Gαs-coupled adenosine A2A receptor closes KCa3.1, providing a clearly defined mechanism by which adenosine inhibits HLMC migration and degranulation. A2A receptor agonists with channel-modulating function may be useful for the treatment of mast cell-mediated disease.
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Affiliation(s)
- S Mark Duffy
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, and Glenfield Hospital, Leicester, UK
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Shen AY, Tsai JH, Teng HC, Huang MH, Wu SN. Inhibition of intermediate-conductance Ca2+-activated K+ channel and cytoprotective properties of 4-piperidinomethyl-2-isopropyl-5-methylphenol. J Pharm Pharmacol 2007; 59:679-85. [PMID: 17524233 DOI: 10.1211/jpp.59.5.0008] [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: 01/29/2023]
Abstract
The ionic mechanisms and cytoprotective activities of 4-piperidinomethyl-2-isopropyl-5-methylphenol (THPI), an analogue of thymol, were investigated in HL-60 granulocytes and in human erythrocytes, respectively. THPI inhibited K+ outward current (I(K)) in a concentration-dependent manner in HL-60 leukocytes, with an IC50 value of 4 microM. Neither iberiotoxin (200 nM) nor paxilline (1 microM) suppressed the amplitude of I(K), whereas clotrimazole (5 microM) significantly inhibited it. In the inside-out configuration of single channel recordings, application of THPI (5 microM) into the bath medium did not alter the single-channel conductance of intermediate-conductance Ca2+-activated K+ (IK(Ca)) channels (i.e K(Ca)3.1 channels), but it suppressed the channel activity significantly. THPI-induced inhibition of IK(Ca) channels was reversed by a further application of 1-ethyl-2-benzimidazolinone (10 microM). THPI-induced reduction in IK(Ca)-channel activity in these cells was primarily due to a decrease in mean open time. These results provide direct evidence that THPI is capable of suppressing the activity of IK(Ca) channels in HL-60 cells. The antioxidant action of THPI also revealed a beneficial cytoprotective effect against mitomycin C-mediated haemolytic effect in human erythrocytes. The results of this study suggest that blockade of IK(Ca) channels and the membrane-protecting activity of THPI would combine to have beneficial effects in lessening the severity of haemolytic crisis and reducing anaemia in sickle cell disease.
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Affiliation(s)
- Ai-Yu Shen
- Basic Medical Science Education Center, Fooyin University, Ta-Liao Hsiang, Kaohsiung Hsien, Taiwan
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Shepherd MC, Duffy SM, Harris T, Cruse G, Schuliga M, Brightling CE, Neylon CB, Bradding P, Stewart AG. KCa3.1 Ca2+ activated K+ channels regulate human airway smooth muscle proliferation. Am J Respir Cell Mol Biol 2007; 37:525-31. [PMID: 17585114 DOI: 10.1165/rcmb.2006-0358oc] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Airway smooth muscle cell hyperplasia contributes to airway remodeling and hyperreactivity characteristic of asthma. Changes to potassium channel activity in proliferating human airway smooth muscle (HASM) cells have been described, but no regulatory role in proliferation has been attributed to them. We sought to investigate the expression of the intermediate conductance calcium-activated potassium channel K(Ca)3.1 in HASM cells and investigate its role in proliferation. Smooth muscle cells derived from human airways were grown in vitro and K(Ca)3.1 channel expression was measured using Western blot, RT-PCR, and patch clamp electrophysiology. Pharmacologic inhibitors of the channel were used in assays of cellular proliferation, and flow cytometry was used to identify cell cycle regulation. HASM cells expressed K(Ca)3.1 channel mRNA, protein, and activity with up-regulation evident after transforming growth factor-beta stimulation. Pharmacologic inhibition of K(Ca)3.1 led to growth arrest in cells stimulated to proliferate with mitogens. These inhibitors did not cause cellular toxicity or induce apoptosis. We have demonstrated, for the first time, the expression of K(Ca)3.1 channels in HASM cells. In addition, we have shown that K(Ca)3.1 channels are important in HASM cell proliferation, making these channels a potential therapeutic target in airway remodeling.
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Affiliation(s)
- Malcolm C Shepherd
- Division of Immunology, Infection and Inflammation, University of Glasgow, Glasgow, United Kingdom.
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Tkaczyk C, Jensen BM, Iwaki S, Gilfillan AM. Adaptive and innate immune reactions regulating mast cell activation: from receptor-mediated signaling to responses. Immunol Allergy Clin North Am 2007; 26:427-50. [PMID: 16931287 DOI: 10.1016/j.iac.2006.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this article, we have described studies that have demonstrated that mast cells can be activated as a consequence of adaptive and innate immune reactions and that these responses can be modified by ligands for other receptors expressed on the surface of mast cells. These various stimuli differentially activate multiple signaling pathways within the mast cells required for the generation and/or release of inflammatory mediators. Thus, the composition of the suite of mediators released and the physiologic ramifications of these responses are dependent on the stimuli and the microenvironment in which the mast cells are activated. Knowledge of the different signaling molecules used by cell surface receptors may allow selective pharmacologic targeting such that inhibiting the adverse effects of mast cell activation can be achieved without influencing the beneficial effects of mast cell activation. The exact interconnections between the signaling pathways initiated by the surface receptors described in this article remain to be completely worked out; thus, this remains a topic for future investigation.
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Affiliation(s)
- Christine Tkaczyk
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 10, Room 11C206, 10 Center Drive, MSC 1881, Bethesda, MD 20892, USA
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Geoffrey R, Jia S, Kwitek AE, Woodliff J, Ghosh S, Lernmark A, Wang X, Hessner MJ. Evidence of a Functional Role for Mast Cells in the Development of Type 1 Diabetes Mellitus in the BioBreeding Rat. THE JOURNAL OF IMMUNOLOGY 2006; 177:7275-86. [PMID: 17082646 DOI: 10.4049/jimmunol.177.10.7275] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Human type 1 diabetes mellitus (T1DM) arises through autoimmune destruction of pancreatic beta cells and is modeled in many respects by the lymphopenic and spontaneously diabetic BioBreeding (BB) DRlyp/lyp rat. Previously, preonset expression profiling of whole DRlyp/lyp pancreatic lymph nodes (PLN) revealed innate immune activity, specifically that of mast cells and eosinophils. Furthermore, we observed that pancreatic islets of DRlyp/lyp rats as well as those of diabetes-inducible BB DR(+/+) rats potentially recruit innate cells through eotaxin expression. Here we determine that lifelong eotaxin expression begins before 40 days of life and is localized specifically to beta cells. In this report, we find that PLN mast cells are more abundant in DRlyp/lyp compared with related BB DR(+/+) rats (2.1 +/- 0.9% vs 0.9 +/- 0.4% of total cells, p < 0.0001). DRlyp/lyp PLN mast cell gene expression profiling revealed an activated population and included significant overrepresentation of transcripts for mast cell protease 1, cationic trypsinogen, carboxypeptidase A, IL-5, and phospholipase Cgamma. In the DR(+/+) rat, which develops T1DM upon depletion of T regulator cells, mast cells displayed gene expression consistent with the negative regulation of degranulation, including significant overrepresentation of transcripts encoding tyrosine phosphatase SHP-1, lipid phosphatase SHIP, and E3 ubiquitin ligase c-Cbl. To recapitulate the negative mast cell regulation observed in the DR(+/+) rats, we treated DRlyp/lyp rats with the mast cell "stabilizer" cromolyn, which significantly (p < 0.05) delayed T1DM onset. These findings are consistent with a growing body of evidence in human and animal models, where a role for mast cells in the initiation and progression of autoimmune disease is emerging.
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Affiliation(s)
- Rhonda Geoffrey
- Max McGee National Research Center for Juvenile Diabetes, Department of Pediatrics at the Medical College of Wisconsin, and Children's Research Institute of the Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA
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Cruse G, Duffy SM, Brightling CE, Bradding P. Functional KCa3.1 K+ channels are required for human lung mast cell migration. Thorax 2006; 61:880-5. [PMID: 16809411 PMCID: PMC2104766 DOI: 10.1136/thx.2006.060319] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Mast cell recruitment and activation are critical for the initiation and progression of inflammation and fibrosis. Mast cells infiltrate specific structures in many diseased tissues such as the airway smooth muscle (ASM) in asthma. This microlocalisation of mast cells is likely to be key to disease pathogenesis. Human lung mast cells (HLMC) express the Ca2+ activated K+ channel K(Ca)3.1 which modulates mediator release, and is proposed to facilitate the retraction of the cell body during migration of several cell types. A study was undertaken to test the hypothesis that blockade of K(Ca)3.1 would attenuate HLMC proliferation and migration. METHODS HLMC were isolated and purified from lung material resected for bronchial carcinoma. HLMC proliferation was assessed by cell counts at various time points following drug exposure. HLMC chemotaxis was assayed using standard Transwell chambers (8 microm pore size). Ion currents were measured using the single cell patch clamp technique. RESULTS K(Ca)3.1 blockade with triarylmethane-34 (TRAM-34) did not inhibit HLMC proliferation and clotrimazole had cytotoxic effects. In contrast, HLMC migration towards the chemokine CXCL10, the chemoattractant stem cell factor, and the supernatants from tumour necrosis factor alpha stimulated asthmatic ASM was markedly inhibited with both the non-selective K(Ca)3.1 blocker charybdotoxin and the highly specific K(Ca)3.1 blocker TRAM-34 in a dose dependent manner. Although K(Ca)3.1 blockade inhibits HLMC migration, K(Ca)3.1 is not opened by the chemotactic stimulus, suggesting that it must be involved downstream of the initial receptor-ligand interactions. CONCLUSIONS Since modulation of K(Ca)3.1 can inhibit HLMC chemotaxis to diverse chemoattractants, the use of K(Ca)3.1 blockers such as TRAM-34 could provide new therapeutic strategies for mast cell mediated diseases such as asthma.
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Affiliation(s)
- G Cruse
- Institute for Lung Health, Department of Infection, Immunity and Inflammation, University of Leicester, Glenfield Hospital, Groby Road, Leicester LE3 9QP, UK.
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Narenjkar J, Assem ESK, Wan BYC, Marsh S, Ezeamuzie CI. Effect of cyclosporin and tacrolimus (FK506) on the antigen-induced mediator release, membrane potential and 86Rb+/K+ and Ca2+ fluxes in the RBL-2H3 cell line. Int Immunopharmacol 2006; 6:742-9. [PMID: 16546704 DOI: 10.1016/j.intimp.2005.11.001] [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] [Received: 07/25/2005] [Revised: 08/16/2005] [Accepted: 11/07/2005] [Indexed: 11/26/2022]
Abstract
The immunosuppressants cyclosporin A (CsA) and tacrolimus (FK506) inhibit the activation by antigen of T-lymphocytes as well as mast cells. The mechanism of their action on mast cells has yet to be elucidated. We, therefore, assessed their effect on antigen-induced histamine and beta-hexosaminidase release, membrane potential changes (bis-oxonol fluorescent probe), 86RB+ (marker for K+)-efflux, the intracellular free calcium concentration ([Ca2+]i in single cells) and 45Ca2+ uptake (CsA only) in RBL-2H3 cells, a mucosal-type mast cell line, passively sensitized with monoclonal mouse IgE antibody. Antigen addition induced depolarization within 1-2 min, followed by slower repolarization, reaching a steady state (approximately 90% repolarization) after 7-9 min. CsA and FK506 each dose-dependently inhibited antigen-induced histamine and beta-hexosaminidase secretion and the membrane repolarization phase, with similar IC50s for both actions, approximately 20 nM for CsA and approximately 2 nM for FK506. Antigen-induced 86Rb+-efflux was also significantly inhibited. Antigen-evoked increase in [Ca2+]i (area under the curve, AUC) was reduced by 35% and 52% in the presence of CsA or FK506 (1 microM each), respectively. However, 45Ca2+-uptake was not inhibited by CsA. These results suggest that both CsA and FK506 may inhibit mediator release from mast cells via blocking two interrelated processes, which are involved in the secretory process: 1. Membrane repolarization phase, which is essential for optimal mediator secretion and is mediated by a Ca2+-sensitive K+-efflux, yet to be further characterized, and (2) Increase in [Ca2+]i, probably via reduction of Ca(+2)-release from intracellular stores, [Ca2+]s.
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Affiliation(s)
- Jamshid Narenjkar
- Department of Pharmacology, University College London, Gower Street, London WC1E 6BT, London, UK
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