1
|
Brito ADF, Silva AS, de Souza AA, Ferreira PB, de Souza ILL, Araujo LCDC, da Silva BA. Supplementation With Spirulina platensis Improves Tracheal Reactivity in Wistar Rats by Modulating Inflammation and Oxidative Stress. Front Pharmacol 2022; 13:826649. [PMID: 35712706 PMCID: PMC9192967 DOI: 10.3389/fphar.2022.826649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Spirulina platensis has shown effectiveness in the treatment of allergic rhinitis in rats, but its action in tracheal reactivity or on markers of relaxation and antioxidant profile has not yet been possible to determine. In this paper, the animals were divided into the groups healthy (SG) and supplemented with S. platensis at doses of 50 (SG50), 150 (SG150), and 500 mg/kg (SG500). We also evaluated nitrite levels, lipid peroxidation, and antioxidant activity through biochemical analysis. For contractile reactivity, only SG500 (pEC50 = 5.2 ± 0.06 showed reduction in carbachol contractile potency. Indomethacin caused a higher contractile response to carbachol in SG150 and SG500. For relaxation, curves for SG150 (pEC50 = 5.0 ± 0.05) and SG500 (pEC50 = 7:3 ± 0:02) were shifted to the left, more so in SG500. We observed an increase in nitrite in the trachea only with supplementation of 500 mg/kg (54.0 ± 8.0 µM), also when compared to SG50 (37.0 ± 10.0 µM) and SG150 (38.0 ± 7.0 µM). We observed a decrease in lipid peroxidation in the plasma and an increase in oxidation inhibition for the trachea and lung in SG150 and SG500, suggesting enhanced antioxidant activity. S. platensis (150/500 mg/kg) decreased the contractile response and increased relaxation by increasing antioxidant activity and nitrite levels and modulating the inflammatory response.
Collapse
Affiliation(s)
- Aline de F Brito
- School of Physical Education, University of Pernambuco, Recife, Brazil.,Post-Graduation Program in Physical Education UPE/UFPB, Recife, Brazil
| | - Alexandre S Silva
- Post-Graduation Program in Physical Education UPE/UFPB, Recife, Brazil.,Physical Education Department, Health Sciences Center, Federal University of Paraiba, João Pessoa, Brazil
| | - Alesandra A de Souza
- Post-Graduation Program in Physical Education UPE/UFPB, Recife, Brazil.,Federal University of Tocantins, Licentiate in Physical Education, Tocantinopolis, Brazil
| | - Paula B Ferreira
- Postgraduate Program in Natural and Synthetic Products Bioactive, Health Sciences Center, Federal University of Paraiba, João Pessoa, Brazil
| | - Iara L L de Souza
- Department of Biological Sciences and Health, Roraima State University, Boa Vista, Brazil
| | - Layanne C da C Araujo
- Department of Biophysics and Physiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Bagnólia A da Silva
- Postgraduate Program in Natural and Synthetic Products Bioactive, Health Sciences Center, Federal University of Paraiba, João Pessoa, Brazil.,Pharmaceutical Sciences Department, Health Sciences Center, Federal University of Paraiba, João Pessoa, Brazil
| |
Collapse
|
2
|
Ferreira SRD, Pessoa RF, Figueiredo IAD, Lima JPM, de Moura TMCF, Bezerra CO, de Oliveira Martins AM, de Carvalho LM, Madruga MS, Cavalcante HC, de Souza Aquino J, de Brito Alves JL, Alves AF, Vasconcelos LHC, de Andrade Cavalcante F. Functional and morphologic dysfunctions in the airways of rats submitted to an experimental model of obesity-exacerbated asthma. Sci Rep 2022; 12:9540. [PMID: 35681069 PMCID: PMC9184493 DOI: 10.1038/s41598-022-13551-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/25/2022] [Indexed: 12/01/2022] Open
Abstract
The obesity-exacerbated asthma phenotype is characterized by more severe asthma symptoms and glucocorticoid resistance. The aim of this study was to standardize an obesity-exacerbated asthma model by a high glycemic level index (HGLI) diet and ovalbumin (OVA) sensitization and challenges in Wistar rats. Animals were divided into groups: control (Ctrl), obese (Ob), asthmatic (Asth), obese asthmatic (Ob + Asth) and obese asthmatic treated with dexamethasone (Ob + Asth + Dexa), and in vivo and in vitro functional and morphological parameters were measured. After HGLI consumption, there was an increase in body weight, fasting blood glucose, abdominal circumferences, body mass index and adiposity index. Respiratory function showed a reduction in pulmonary tidal volume and ventilation. In isolated tracheas, carbachol showed an increase in contractile efficacy in the Ob, Ob + Asth and Ob + Asth + Dexa, but mostly on Ob + Asth. Histological analysis of lungs showed peribronchovascular inflammation and smooth muscle hypertrophy and extracellular remodeling on Ob + Asth and Ob + Asth + Dexa. An obesity-exacerbated asthma model was successfully established. Therefore, this model allows further molecular investigations and the search for new therapies for the treatment and relief of symptoms of patients with obesity-induced resistant asthma.
Collapse
Affiliation(s)
- Sarah Rebeca Dantas Ferreira
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | - Rayane Fernandes Pessoa
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | - Indyra Alencar Duarte Figueiredo
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | - João Pedro Moura Lima
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | | | - Cleyton Oliveira Bezerra
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | | | - Leila Moreira de Carvalho
- Departamento de Engenharia de Alimentos, Centro de Tecnologia, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | - Marta Suely Madruga
- Departamento de Engenharia de Alimentos, Centro de Tecnologia, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | | | - Jailane de Souza Aquino
- Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Departamento de Nutrição, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | - José Luiz de Brito Alves
- Departamento de Nutrição, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil
| | - Adriano Francisco Alves
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária, João Pessoa, PB, Brazil
| | - Luiz Henrique César Vasconcelos
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil. .,Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil. .,Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária, João Pessoa, PB, Brazil.
| | - Fabiana de Andrade Cavalcante
- Instituto de Pesquisa em Fármacos e Medicamentos, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária, João Pessoa, PB, Brazil
| |
Collapse
|
3
|
Freitas MM, Cavalcante PM, Duarte-Filho LAMS, Macedo CAF, Brito MC, Menezes PMN, Ribeiro TF, Costa SM, Carvalho BAG, Ribeiro FPRA, Moura MPS, Silva FS, Ribeiro LAA. Investigation of the relaxing effect of a camphor nanoemulsion on rat isolated trachea. Chem Biol Interact 2021; 348:109656. [PMID: 34516975 DOI: 10.1016/j.cbi.2021.109656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 07/15/2021] [Accepted: 09/09/2021] [Indexed: 10/20/2022]
Abstract
Asthma is a chronic inflammatory disease that targeting lower airways, being characterized by bronchial smooth muscle hyper responsiveness and mucus hypersecretion. Asthma is considered the most common respiratory disease in the world, affecting approximately 235 million individuals. The main therapy sometimes fails to establish clinical improvement in patients, which leads to a constant search for new alternatives. Camphor is a transparent solid monoterpene with a strong aroma, which due to its high lipophilicity is insoluble in water. Nanostructured carrier systems have shown promise as a delivery system for lipophilic compounds such as monoterpenes. Therefore, the objective of this work was to evaluate the relaxant effect of nanoemulsified camphor (NEC), as well as the mechanism of action of that monoterpene, in isolated rat trachea. The results obtained demonstrated that NEC promote relaxation of the isolated rat trachea when smooth muscle contraction was induced by both carbachol (CCh) and KCl, presenting a pCE50 of 2.25 ± 0.27 and 3.30 ± 0.07, respectively. In the presence of dexamethasone (DEXA), tetraethylammonium (TEA), glibenclamide (GLIB), 1H-[1,2,4]-oxadiazole-[4,3,-a]-quinoxaline-1-one (ODQ) and ruthenium red (RR) there was a significant difference in at least one of the evaluated pharmacological parameters, such as concentration-response curves shape, Emax or pCE50. As conclusion, NEC may be involved with β-adrenergic receptors, channels for K+ sensitive to ATP (KATP) or Channels for K+ opened by Ca2+ (KCa), increase in prostanoids and with receptor channel with transient potential (TRPv). In conclusion, β-adrenergic receptors, prostanoids, nitric oxide (NO), ATP-sensitive K+ channels (KATP), Ca2+-opened K+ channels (KCa), and transient receptor potential cation channel subfamily V (TRPV) are involved in the relaxing effect of NEC. In addition, the mechanism of action of NEC may be involved with the signal transduction pathway Nitric Oxide/soluble guanylyl cyclase/cGMP/cGMP-activated protein kinase. NEC, therefore, demonstrates spasmolytic activity when presenting tracheal relaxation compared to CCh and KCl contracturants.
Collapse
Affiliation(s)
- Maíra M Freitas
- Programa de Pós-Graduação em Biociências (PPGB), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Pedro M Cavalcante
- Programa de Pós-Graduação em Biociências (PPGB), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Luiz A M S Duarte-Filho
- Programa de Pós-Graduação em Biociências (PPGB), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Cicero A F Macedo
- Programa de Pós-graduação em Biotecnologia, Universidade Estadual de Feira de Santana (UEFS), Av. Transnordestina, S/N, Novo Horizonte, CEP: 44036-900, Feira de Santana-Ba, Brazil
| | - Mariana C Brito
- Programa de Pós-graduação em Biotecnologia, Universidade Estadual de Feira de Santana (UEFS), Av. Transnordestina, S/N, Novo Horizonte, CEP: 44036-900, Feira de Santana-Ba, Brazil
| | - Pedro M N Menezes
- Rede Nordeste de Biotecnologia (RENORBIO), Universidade Federal Rural de Pernambuco (UFRPE), Rua Dom Manuel de Medeiros, S/N, Dois Irmãos, CEP: 52171-900, Recife-PE, Brazil
| | - Thiago F Ribeiro
- Rede Nordeste de Biotecnologia (RENORBIO), Universidade Federal Rural de Pernambuco (UFRPE), Rua Dom Manuel de Medeiros, S/N, Dois Irmãos, CEP: 52171-900, Recife-PE, Brazil
| | - Sâmara M Costa
- Curso de Graduação em Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Bárbara A G Carvalho
- Curso de Graduação em Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Fernanda P R A Ribeiro
- Colegiado de Ciências Farmacêuticas (CFARM), Laboratório de Farmacologia Experimental (LAFEX), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Marigilson P S Moura
- Programa de Pós-Graduação em Biociências (PPGB), Colegiado de Ciências Farmacêuticas (CFARM), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Fabricio S Silva
- Programa de Pós-Graduação em Biociências (PPGB), Colegiado de Ciências Farmacêuticas (CFARM), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil
| | - Luciano A A Ribeiro
- Programa de Pós-Graduação em Biociências (PPGB), Colegiado de Ciências Farmacêuticas (CFARM), Universidade Federal do Vale do São Francisco (UNIVASF), Campus Centro, Av. José de Sá Maniçoba, S/N, Cx. Postal 252, CEP: 56.304-205, Petrolina-PE, Brazil.
| |
Collapse
|
4
|
Mokry J, Urbanova A, Kertys M, Mokra D. Inhibitors of phosphodiesterases in the treatment of cough. Respir Physiol Neurobiol 2018; 257:107-114. [PMID: 29337269 DOI: 10.1016/j.resp.2018.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/28/2017] [Accepted: 01/11/2018] [Indexed: 02/08/2023]
Abstract
A group of 11 enzyme families of metalophosphohydrolases called phosphodiesterases (PDEs) is responsible for a hydrolysis of intracellular cAMP and cGMP. Xanthine derivatives (methylxanthines) inhibit PDEs without selective action on their single isoforms and lead to many pharmacological effects, e.g. bronchodilation, anti-inflammatory and immunomodulating effects, and thus they can modulate the cough reflex. Contrary, selective PDE inhibitors have been developed to inhibit PDE isoforms with different pharmacological effects based on their tissue expression. In this paper, effects of non-selective PDE inhibitors (e.g. theophylline) are discussed, with a description of other putative mechanisms in their effects on cough. Antitussive effects of selective inhibitors of several PDE isoforms are reviewed, focusing on PDE1, PDE3, PDE4, PDE5 and PDE7. The inhibition of PDEs suggests participation of bronchodilation, suppression of TRPV channels and anti-inflammatory action in cough suppression. Selective PDE3, PDE4 and PDE5 inhibitors have demonstrated the most significant cough suppressive effects, confirming their benefits in chronic inflammatory airway diseases associated with bronchoconstriction and cough.
Collapse
Affiliation(s)
- Juraj Mokry
- Department of Pharmacology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia; Biomedical Center Martin (BioMed), Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia.
| | - Anna Urbanova
- Department of Pharmacology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia; Biomedical Center Martin (BioMed), Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Martin Kertys
- Department of Pharmacology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia; Biomedical Center Martin (BioMed), Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Daniela Mokra
- Biomedical Center Martin (BioMed), Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia; Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| |
Collapse
|
5
|
Brito AF, Silva AS, Souza ILL, Pereira JC, Martins IRR, Silva BA. Intensity of swimming exercise influences tracheal reactivity in rats. J Smooth Muscle Res 2016; 51:70-81. [PMID: 26497013 PMCID: PMC5137269 DOI: 10.1540/jsmr.51.70] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Studies that evaluate the mechanisms for increased airway responsiveness are very sparse,
although there are reports of exercise-induced bronchospasm. Therefore, we have evaluated
the tracheal reactivity and the rate of lipid peroxidation after different intensities of
swimming exercise in rats. Thus, male Wistar rats (age 8 weeks; 250–300 g) underwent a
forced swimming exercise for 1 h whilst carrying attached loads of 3, 4, 5, 6 and 8% of
their body weight (groups G3, G4, G5, G6 and G8, respectively; n=5 each).
Immediately after the test, the trachea of each rat was removed and suspended in an organ
bath to evaluate contractile and relaxant responses. The rate of lipid peroxidation was
estimated by measuring malondialdehyde levels. According to a one-way ANOVA, all trained
groups showed a significant decrease in the relaxation induced by aminophylline
(10−12–10−1 M) (pD2=3.1, 3.2, 3.3, 3.3 and 3.2, respectively for
G3, G4, G5, G6 and G8) compared to the control group (pD2=4.6) and the Emax
values of G5, G6, G8 groups were reduced by 94.2, 88.0 and 77.0%, respectively.
Additionally, all trained groups showed a significant increase in contraction induced by
carbachol (10−9–10−3 M) (pD2=6.0, 6.5, 6.5, 7.2 and 7.3,
respectively for G3, G4, G5, G6 and G8) compared to the control group (pD2=5.7). Lipid
peroxidation levels of G3, G4 and G5 were similar in both the trachea and lung, however G6
and G8 presented an increased peroxidation in the trachea. In conclusion, a single bout of
swimming exercise acutely altered tracheal responsiveness in an intensity-related manner
and the elevation in lipid peroxidation indicates a degree of oxidative stress
involvement.
Collapse
Affiliation(s)
- Aline F Brito
- Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Paraíba, Brasil
| | | | | | | | | | | |
Collapse
|
6
|
Brueggemann LI, Haick JM, Neuburg S, Tate S, Randhawa D, Cribbs LL, Byron KL. KCNQ (Kv7) potassium channel activators as bronchodilators: combination with a β2-adrenergic agonist enhances relaxation of rat airways. Am J Physiol Lung Cell Mol Physiol 2014; 306:L476-86. [PMID: 24441871 PMCID: PMC3949081 DOI: 10.1152/ajplung.00253.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 01/16/2014] [Indexed: 12/19/2022] Open
Abstract
KCNQ (Kv7 family) potassium (K(+)) channels were recently found in airway smooth muscle cells (ASMCs) from rodent and human bronchioles. In the present study, we evaluated expression of KCNQ channels and their role in constriction/relaxation of rat airways. Real-time RT-PCR analysis revealed expression of KCNQ4 > KCNQ5 > KCNQ1 > KCNQ2 > KCNQ3, and patch-clamp electrophysiology detected KCNQ currents in rat ASMCs. In precision-cut lung slices, the KCNQ channel activator retigabine induced a concentration-dependent relaxation of small bronchioles preconstricted with methacholine (MeCh; EC50 = 3.6 ± 0.3 μM). Bronchoconstriction was also attenuated in the presence of two other structurally unrelated KCNQ channel activators: zinc pyrithione (ZnPyr; 1 μM; 22 ± 7%) and 2,5-dimethylcelecoxib (10 μM; 24 ± 8%). The same three KCNQ channel activators increased KCNQ currents in ASMCs by two- to threefold. The bronchorelaxant effects of retigabine and ZnPyr were prevented by inclusion of the KCNQ channel blocker XE991. A long-acting β2-adrenergic receptor agonist, formoterol (10 nM), did not increase KCNQ current amplitude in ASMCs, but formoterol (1-1,000 nM) did induce a time- and concentration-dependent relaxation of rat airways, with a notable desensitization during a 30-min treatment or with repetitive treatments. Coadministration of retigabine (10 μM) with formoterol produced a greater peak and sustained reduction of MeCh-induced bronchoconstriction and reduced the apparent desensitization observed with formoterol alone. Our findings support a role for KCNQ K(+) channels in the regulation of airway diameter. A combination of a β2-adrenergic receptor agonist with a KCNQ channel activator may improve bronchodilator therapy.
Collapse
Affiliation(s)
- Lioubov I Brueggemann
- Dept. of Molecular Pharmacology & Therapeutics, Loyola Univ. Chicago, Stritch School of Medicine, 2160 S. First Ave., Bldg. 102, Rm. 3634, Maywood, IL 60153.
| | | | | | | | | | | | | |
Collapse
|
7
|
Zhang CH, Lifshitz LM, Uy KF, Ikebe M, Fogarty KE, ZhuGe R. The cellular and molecular basis of bitter tastant-induced bronchodilation. PLoS Biol 2013; 11:e1001501. [PMID: 23472053 PMCID: PMC3589262 DOI: 10.1371/journal.pbio.1001501] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 01/24/2013] [Indexed: 01/13/2023] Open
Abstract
Bitter tastants can activate bitter taste receptors on constricted smooth muscle cells to inhibit L-type calcium channels and induce bronchodilation. Bronchodilators are a standard medicine for treating airway obstructive diseases, and β2 adrenergic receptor agonists have been the most commonly used bronchodilators since their discovery. Strikingly, activation of G-protein-coupled bitter taste receptors (TAS2Rs) in airway smooth muscle (ASM) causes a stronger bronchodilation in vitro and in vivo than β2 agonists, implying that new and better bronchodilators could be developed. A critical step towards realizing this potential is to understand the mechanisms underlying this bronchodilation, which remain ill-defined. An influential hypothesis argues that bitter tastants generate localized Ca2+ signals, as revealed in cultured ASM cells, to activate large-conductance Ca2+-activated K+ channels, which in turn hyperpolarize the membrane, leading to relaxation. Here we report that in mouse primary ASM cells bitter tastants neither evoke localized Ca2+ events nor alter spontaneous local Ca2+ transients. Interestingly, they increase global intracellular [Ca2+]i, although to a much lower level than bronchoconstrictors. We show that these Ca2+ changes in cells at rest are mediated via activation of the canonical bitter taste signaling cascade (i.e., TAS2R-gustducin-phospholipase Cβ [PLCβ]- inositol 1,4,5-triphosphate receptor [IP3R]), and are not sufficient to impact airway contractility. But activation of TAS2Rs fully reverses the increase in [Ca2+]i induced by bronchoconstrictors, and this lowering of the [Ca2+]i is necessary for bitter tastant-induced ASM cell relaxation. We further show that bitter tastants inhibit L-type voltage-dependent Ca2+ channels (VDCCs), resulting in reversal in [Ca2+]i, and this inhibition can be prevented by pertussis toxin and G-protein βγ subunit inhibitors, but not by the blockers of PLCβ and IP3R. Together, we suggest that TAS2R stimulation activates two opposing Ca2+ signaling pathways via Gβγ to increase [Ca2+]i at rest while blocking activated L-type VDCCs to induce bronchodilation of contracted ASM. We propose that the large decrease in [Ca2+]i caused by effective tastant bronchodilators provides an efficient cell-based screening method for identifying potent dilators from among the many thousands of available bitter tastants. Bitter taste receptors (TAS2Rs), a G-protein-coupled receptor family long thought to be solely expressed in taste buds on the tongue, have recently been detected in airways. Bitter substances can activate TAS2Rs in airway smooth muscle to cause greater bronchodilation than β2 adrenergic receptor agonists, the most commonly used bronchodilators. However, the mechanisms underlying this bronchodilation remain elusive. Here we show that, in resting primary airway smooth muscle cells, bitter tastants activate a TAS2R-dependent signaling pathway that results in an increase in intracellular calcium levels, albeit to a level much lower than that produced by bronchoconstrictors. In bronchoconstricted cells, however, bitter tastants reverse the bronchoconstrictor-induced increase in calcium levels, which leads to the relaxation of smooth muscle cells. We find that this reversal is due to inhibition of L-type calcium channels. Our results suggest that under normal conditions, bitter tastants can activate TAS2Rs to modestly increase calcium levels, but that when smooth muscle cells are constricted, they can block L-type calcium channels to induce bronchodilation. We postulate that this novel mechanism could operate in other extraoral cells expressing TAS2Rs.
Collapse
Affiliation(s)
- Cheng-Hai Zhang
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Lawrence M. Lifshitz
- Biomedical Imaging Group, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Karl F. Uy
- Department of Surgery, Division of Thoracic Surgery, University of Massachusetts Memorial Medical Center, Worcester, Massachusetts, United States of America
| | - Mitsuo Ikebe
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Kevin E. Fogarty
- Biomedical Imaging Group, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Ronghua ZhuGe
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Biomedical Imaging Group, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|