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Keshavarz M, Ruppert AL, Meiners M, Poharkar K, Liu S, Mahmoud W, Winterberg S, Hartmann P, Mermer P, Perniss A, Offermanns S, Kummer W, Schütz B. Bitter tastants relax the mouse gallbladder smooth muscle independent of signaling through tuft cells and bitter taste receptors. Sci Rep 2024; 14:18447. [PMID: 39117690 PMCID: PMC11310472 DOI: 10.1038/s41598-024-69287-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 08/02/2024] [Indexed: 08/10/2024] Open
Abstract
Disorders of gallbladder motility can lead to serious pathology. Bitter tastants acting upon bitter taste receptors (TAS2R family) have been proposed as a novel class of smooth muscle relaxants to combat excessive contraction in the airways and other organs. To explore whether this might also emerge as an option for gallbladder diseases, we here tested bitter tastants for relaxant properties and profiled Tas2r expression in the mouse gallbladder. In organ bath experiments, the bitter tastants denatonium, quinine, dextromethorphan, and noscapine, dose-dependently relaxed the pre-contracted gallbladder. Utilizing gene-deficient mouse strains, neither transient receptor potential family member 5 (TRPM5), nor the Tas2r143/Tas2r135/Tas2r126 gene cluster, nor tuft cells proved to be required for this relaxation, indicating direct action upon smooth muscle cells (SMC). Accordingly, denatonium, quinine and dextromethorphan increased intracellular calcium concentration preferentially in isolated gallbladder SMC and, again, this effect was independent of TRPM5. RT-PCR revealed transcripts of Tas2r108, Tas2r126, Tas2r135, Tas2r137, and Tas2r143, and analysis of gallbladders from mice lacking tuft cells revealed preferential expression of Tas2r108 and Tas2r137 in tuft cells. A TAS2R143-mCherry reporter mouse labeled tuft cells in the gallbladder epithelium. An in silico analysis of a scRNA sequencing data set revealed Tas2r expression in only few cells of different identity, and from in situ hybridization histochemistry, which did not label distinct cells. Our findings demonstrate profound tuft cell- and TRPM5-independent relaxing effects of bitter tastants on gallbladder smooth muscle, but do not support the concept that these effects are mediated by bitter receptors.
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Affiliation(s)
- Maryam Keshavarz
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany.
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany.
- Anatomy and Cell Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany.
| | - Anna-Lena Ruppert
- Institute for Anatomy and Cell Biology, Philipps-University, Marburg, Germany
| | - Mirjam Meiners
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
| | - Krupali Poharkar
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
| | - Shuya Liu
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Wafaa Mahmoud
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
- Department of Anatomy, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Sarah Winterberg
- Institute for Anatomy and Cell Biology, Philipps-University, Marburg, Germany
| | - Petra Hartmann
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
| | - Petra Mermer
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
| | - Alexander Perniss
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
- Division of Allergy and Clinical Immunology, Department of Medicine, Jeff and Penny Vinik Center for Allergic Disease Research, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Stefan Offermanns
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Wolfgang Kummer
- Institute for Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University, Giessen, Germany.
- Excellence Cluster Cardio-Pulmonary Institute, Justus Liebig University, Giessen, Germany.
| | - Burkhard Schütz
- Institute for Anatomy and Cell Biology, Philipps-University, Marburg, Germany.
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Bloxham CJ, Hulme KD, Fierro F, Fercher C, Pegg CL, O'Brien SL, Foster SR, Short KR, Furness SGB, Reichelt ME, Niv MY, Thomas WG. Cardiac human bitter taste receptors contain naturally occurring variants that alter function. Biochem Pharmacol 2024; 219:115932. [PMID: 37989413 DOI: 10.1016/j.bcp.2023.115932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/26/2023] [Accepted: 11/16/2023] [Indexed: 11/23/2023]
Abstract
Bitter taste receptors (T2R) are a subfamily of G protein-coupled receptors that enable humans to detect aversive and toxic substances. The ability to discern bitter compounds varies between individuals and is attributed mainly to naturally occurring T2R polymorphisms. T2Rs are also expressed in numerous non-gustatory tissues, including the heart, indicating potential contributions to cardiovascular physiology. In this study. T2Rs that have previously been identified in human cardiac tissues (T2Rs - 10, 14, 30, 31, 46 and 50) and their naturally occurring polymorphisms were functionally characterised. The ligand-dependent signaling responses of some T2R variants were completely abolished (T2R30 Leu252 and T2R46 Met228), whereas other receptor variants had moderate changes in their maximal response, but not potency, relative to wild type. Using a cAMP fluorescent biosensor, we reveal the productive coupling of T2R14, but not the T2R14 Phe201 variant, to endogenous Gαi. Modeling revealed that these variants resulted in altered interactions that generally affected ligand binding (T2R30 Leu252) or Gα protein interactions (T2R46 Met228 and T2R14 Phe201), rather than receptor structural stability. Interestingly, this study is the first to show a difference in signaling for T2R50 Tyr203 (rs1376251) which has been associated with cardiovascular disease. The observation of naturally occurring functional variation in the T2Rs with the greatest expression in the heart is important, as their discovery should prove useful in deciphering the role of T2Rs within the cardiovascular system.
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Affiliation(s)
- Conor J Bloxham
- School of Biomedical Sciences, Faculty of Medicine, University of Queensland, QLD, Australia; Regenerative Medicine in Cardiovascular Diseases, First Department of Medicine, Klinikum rechts der Isar, Technical University of Munich, Germany
| | - Katina D Hulme
- School of Chemistry and Molecular Biosciences, Faculty of Science, University of Queensland, QLD, Australia; Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Fabrizio Fierro
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Israel
| | - Christian Fercher
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD, Australia
| | - Cassandra L Pegg
- School of Chemistry and Molecular Biosciences, Faculty of Science, University of Queensland, QLD, Australia
| | - Shannon L O'Brien
- Institute of Metabolism and Systems Research, University of Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Simon R Foster
- School of Biomedical Sciences, Faculty of Medicine, University of Queensland, QLD, Australia; QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Kirsty R Short
- School of Chemistry and Molecular Biosciences, Faculty of Science, University of Queensland, QLD, Australia
| | - Sebastian G B Furness
- School of Biomedical Sciences, Faculty of Medicine, University of Queensland, QLD, Australia; Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Melissa E Reichelt
- School of Biomedical Sciences, Faculty of Medicine, University of Queensland, QLD, Australia
| | - Masha Y Niv
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Israel
| | - Walter G Thomas
- School of Biomedical Sciences, Faculty of Medicine, University of Queensland, QLD, Australia.
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Talmon M, Massara E, Quaregna M, De Battisti M, Boccafoschi F, Lecchi G, Puppo F, Bettega Cajandab MA, Salamone S, Bovio E, Boldorini R, Riva B, Pollastro F, Fresu LG. Bitter taste receptor (TAS2R) 46 in human skeletal muscle: expression and activity. Front Pharmacol 2023; 14:1205651. [PMID: 37771728 PMCID: PMC10522851 DOI: 10.3389/fphar.2023.1205651] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/27/2023] [Indexed: 09/30/2023] Open
Abstract
Bitter taste receptors are involved not only in taste perception but in various physiological functions as their anatomical location is not restricted to the gustatory system. We previously demonstrated expression and activity of the subtype hTAS2R46 in human airway smooth muscle and broncho-epithelial cells, and here we show its expression and functionality in human skeletal muscle cells. Three different cellular models were used: micro-dissected human skeletal tissues, human myoblasts/myotubes and human skeletal muscle cells differentiated from urine stem cells of healthy donors. We used qPCR, immunohistochemistry and immunofluorescence analysis to evaluate gene and protein hTAS2R46 expression. In order to explore receptor activity, cells were incubated with the specific bitter ligands absinthin and 3ß-hydroxydihydrocostunolide, and calcium oscillation and relaxation were evaluated by calcium imaging and collagen assay, respectively, after a cholinergic stimulus. We show, for the first time, experimentally the presence and functionality of a type 2 bitter receptor in human skeletal muscle cells. Given the tendentially protective role of the bitter receptors starting from the oral cavity and following also in the other ectopic sites, and given its expression already at the myoblast level, we hypothesize that the bitter receptor can play an important role in the development, maintenance and in the protection of muscle tissue functions.
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Affiliation(s)
- Maria Talmon
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Erika Massara
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Martina Quaregna
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Marta De Battisti
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Francesca Boccafoschi
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Giulia Lecchi
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Federico Puppo
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | | | - Stefano Salamone
- Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy
| | - Enrica Bovio
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Renzo Boldorini
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
| | - Beatrice Riva
- Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy
| | - Federica Pollastro
- Department of Pharmaceutical Sciences, University of Piemonte Orientale, Novara, Italy
| | - Luigia G. Fresu
- Department of Health Sciences, School of Medicine, University of Piemonte Orientale, Novara, Italy
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Welcome MO, Dogo D, Nikos E Mastorakis. Cellular mechanisms and molecular pathways linking bitter taste receptor signalling to cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases. Inflammopharmacology 2023; 31:89-117. [PMID: 36471190 PMCID: PMC9734786 DOI: 10.1007/s10787-022-01086-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/11/2022] [Indexed: 12/12/2022]
Abstract
Heart diseases and related complications constitute a leading cause of death and socioeconomic threat worldwide. Despite intense efforts and research on the pathogenetic mechanisms of these diseases, the underlying cellular and molecular mechanisms are yet to be completely understood. Several lines of evidence indicate a critical role of inflammatory and oxidative stress responses in the development and progression of heart diseases. Nevertheless, the molecular machinery that drives cardiac inflammation and oxidative stress is not completely known. Recent data suggest an important role of cardiac bitter taste receptors (TAS2Rs) in the pathogenetic mechanism of heart diseases. Independent groups of researchers have demonstrated a central role of TAS2Rs in mediating inflammatory, oxidative stress responses, autophagy, impulse generation/propagation and contractile activities in the heart, suggesting that dysfunctional TAS2R signalling may predispose to cardiac inflammatory and oxidative stress disorders, characterised by contractile dysfunction and arrhythmia. Moreover, cardiac TAS2Rs act as gateway surveillance units that monitor and detect toxigenic or pathogenic molecules, including microbial components, and initiate responses that ultimately culminate in protection of the host against the aggression. Unfortunately, however, the molecular mechanisms that link TAS2R sensing of the cardiac milieu to inflammatory and oxidative stress responses are not clearly known. Therefore, we sought to review the possible role of TAS2R signalling in the pathophysiology of cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases. Potential therapeutic significance of targeting TAS2R or its downstream signalling molecules in cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction is also discussed.
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Affiliation(s)
- Menizibeya O Welcome
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Nile University of Nigeria, Plot 681 Cadastral Zone, C-00 Research and Institution Area, Jabi Airport Road Bypass, FCT, Abuja, Nigeria.
| | - Dilli Dogo
- Department of Surgery, Faculty of Clinical Sciences, College of Health Sciences, Nile University of Nigeria, Abuja, Nigeria
| | - Nikos E Mastorakis
- Technical University of Sofia, Klement Ohridksi 8, Sofia, 1000, Bulgaria
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5
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Delompré T, Belloir C, Martin C, Salles C, Briand L. Detection of Bitterness in Vitamins Is Mediated by the Activation of Bitter Taste Receptors. Nutrients 2022; 14:nu14194141. [PMID: 36235793 PMCID: PMC9571608 DOI: 10.3390/nu14194141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022] Open
Abstract
Vitamins are known to generate bitterness, which may contribute to an off-taste or aftertaste for some nutritional supplements. This negative sensation can lead to a reduction in their consumption. Little is known about the bitter taste threshold and taste sensing system for the bitter taste detection of vitamins. To better understand the mechanisms involved in bitterness perception, we combined taste receptor functional assays and sensory analysis. In humans, bitter taste detection is mediated by 25 G-protein-coupled receptors belonging to the TAS2R family. First, we studied the bitterness of thirteen vitamins using a cellular-based functional taste receptor assay. We found four vitamins that can stimulate one or more TAS2Rs. For each positive molecule-receptor combination, we tested seven increasing concentrations to determine the half-maximal effective concentration (EC50) and the cellular bitter taste threshold. Second, we measured the bitter taste detection threshold for four vitamins that exhibit a strong bitter taste using a combination of ascending series and sensory difference tests. A combination of sensory and biological data can provide useful results that explain the perception of vitamin bitterness and its real contribution to the off-taste of nutritional supplements.
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Ki SY, Jeong YT. Taste Receptors beyond Taste Buds. Int J Mol Sci 2022; 23:ijms23179677. [PMID: 36077074 PMCID: PMC9455917 DOI: 10.3390/ijms23179677] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
Taste receptors are responsible for detecting their ligands not only in taste receptor cells (TRCs) but also in non-gustatory organs. For several decades, many research groups have accumulated evidence for such “ectopic” expression of taste receptors. More recently, some of the physiologic functions (apart from taste) of these ectopic taste receptors have been identified. Here, we summarize our current understanding of these ectopic taste receptors across multiple organs. With a particular focus on the specialized epithelial cells called tuft cells, which are now considered siblings of type II TRCs, we divide the ectopic expression of taste receptors into two categories: taste receptors in TRC-like cells outside taste buds and taste receptors with surprising ectopic expression in completely different cell types.
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Affiliation(s)
- Su Young Ki
- Department of Pharmacology, Korea University College of Medicine, Seoul 02841, Korea
| | - Yong Taek Jeong
- Department of Pharmacology, Korea University College of Medicine, Seoul 02841, Korea
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Korea
- Correspondence: ; Tel.: +82-2-2286-1295
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7
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New values of a type 2 taste receptor TAS2R14 in thyroid cancer. Acta Biochim Biophys Sin (Shanghai) 2022; 54:587-589. [PMID: 35607961 PMCID: PMC9828633 DOI: 10.3724/abbs.2022026] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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D'Urso O, Drago F. Pharmacological significance of extra-oral taste receptors. Eur J Pharmacol 2021; 910:174480. [PMID: 34496302 DOI: 10.1016/j.ejphar.2021.174480] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/23/2021] [Accepted: 09/01/2021] [Indexed: 01/17/2023]
Abstract
It has recently been shown that taste receptors, in addition to being present in the oral cavity, exist in various extra-oral organs and tissues such as the thyroid, lungs, skin, stomach, intestines, and pancreas. Although their physiological function is not yet fully understood, it appears that they can help regulate the body's homeostasis and provide an additional defense function against pathogens. Since the vast majority of drugs are bitter, the greatest pharmacological interest is in the bitter taste receptors. In this review, we describe how bitter taste 2 receptors (TAS2Rs) induce bronchodilation and mucociliary clearance in the airways, muscle relaxation in various tissues, inhibition of thyroid stimulating hormone (TSH) in thyrocytes, and release of glucagon-like peptide-1 (GLP-1) and ghrelin in the digestive system. In fact, substances such as dextromethorphan, chloroquine, methimazole and probably glimepiride, being agonists of TAS2Rs, lead to these effects. TAS2Rs and taste 1 receptors (TAS1R2/3) are G protein-coupled receptors (GPCR). TAS1R2/3 are responsible for sweet taste perception and may induce GLP-1 release and insulin secretion. Umami taste receptors, belonging to the same superfamily of receptors, perform a similar function with regard to insulin. The sour and salty taste receptors work in a similar way, both being channel receptors sensitive to amiloride. Finally, gene-protein coupled receptor 40 (GPR40) and GPR120 for fatty taste perception are also protein-coupled receptors and may induce GLP-1 secretion and insulin release, similar to those of other receptors belonging to the same superfamily.
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Affiliation(s)
- Ottavio D'Urso
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia, 97, 95125 Catania, Italy
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia, 97, 95125 Catania, Italy.
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9
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Abstract
Bitter taste-sensing type 2 receptors (TAS2Rs or T2Rs), belonging to the subgroup of family A G-protein coupled receptors (GPCRs), are of crucial importance in the perception of bitterness. Although in the first instance, TAS2Rs were considered to be exclusively distributed in the apical microvilli of taste bud cells, numerous studies have detected these sensory receptor proteins in several extra-oral tissues, such as in pancreatic or ovarian tissues, as well as in their corresponding malignancies. Critical points of extra-oral TAS2Rs biology, such as their structure, roles, signaling transduction pathways, extensive mutational polymorphism, and molecular evolution, have been currently broadly studied. The TAS2R cascade, for instance, has been recently considered to be a pivotal modulator of a number of (patho)physiological processes, including adipogenesis or carcinogenesis. The latest advances in taste receptor biology further raise the possibility of utilizing TAS2Rs as a therapeutic target or as an informative index to predict treatment responses in various disorders. Thus, the focus of this review is to provide an update on the expression and molecular basis of TAS2Rs functions in distinct extra-oral tissues in health and disease. We shall also discuss the therapeutic potential of novel TAS2Rs targets, which are appealing due to their ligand selectivity, expression pattern, or pharmacological profiles.
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Affiliation(s)
- Kamila Tuzim
- Department of Clinical Pathomorphology, Medical University of Lublin, ul. Jaczewskiego 8b, 20-090, Lublin, Poland.
| | - Agnieszka Korolczuk
- Department of Clinical Pathomorphology, Medical University of Lublin, ul. Jaczewskiego 8b, 20-090, Lublin, Poland
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Li H, Li LF, Zhang ZJ, Wu CJ, Yu SJ. Sensory evaluation, chemical structures, and threshold concentrations of bitter-tasting compounds in common foodstuffs derived from plants and maillard reaction: A review. Crit Rev Food Sci Nutr 2021; 63:2277-2317. [PMID: 34542344 DOI: 10.1080/10408398.2021.1973956] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The bitterness of foodstuffs is often associated with toxicity, which negatively influences product acceptability. However, bitter compounds have many benefits, and a slight bitter taste is sometimes favored. In this review, we summarize the methods used to isolate and evaluate the taste of bitter compounds in different foods. The chemical structures and threshold concentrations of these compounds are also recapped. Although the structures and thresholds of many bitter compounds have been confirmed, further studies are needed to develop detailed bitter-masking strategies and establish the relation between functional groups (hetero-cyclic substituents and bonding types) and taste quality. Furthermore, a comprehensive bitterness database and chemometric data must be provided in order to quickly assess the bitterness of unfamiliar products.
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Affiliation(s)
- He Li
- School of Chemical Engineering and Technology, North University of China, Taiyuan, China.,College of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Li-Feng Li
- School of Environment and Safety Engineering, North University of China, Taiyuan, China
| | - Zhi-Jun Zhang
- School of Chemical Engineering and Technology, North University of China, Taiyuan, China
| | - Chun-Jian Wu
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Shu-Juan Yu
- College of Food Science and Engineering, South China University of Technology, Guangzhou, China
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11
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Lu P, ElMallah MK, Liu Z, Wu C, Chen J, Lifshitz LM, ZhuGe R. Genetic deletion of the Tas2r143/Tas2r135/Tas2r126 cluster reveals that TAS2Rs may not mediate bitter tastant-induced bronchodilation. J Cell Physiol 2021; 236:6407-6423. [PMID: 33559206 PMCID: PMC8223514 DOI: 10.1002/jcp.30315] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 01/19/2021] [Accepted: 01/27/2021] [Indexed: 11/09/2022]
Abstract
Bitter taste receptors (TAS2Rs) and their signaling elements are detected throughout the body, and bitter tastants induce a wide variety of biological responses in tissues and organs outside the mouth. However, the roles of TAS2Rs in these responses remain to be tested and established genetically. Here, we employed the CRISPR/Cas9 gene-editing technique to delete three bitter taste receptors-Tas2r143/Tas2r135/Tas2r126 (i.e., Tas2r triple knockout [TKO]) in mice. The fidelity and effectiveness of the Tas2r deletions were validated genetically at DNA and messenger RNA levels and functionally based on the tasting of TAS2R135 and TAS2R126 agonists. Bitter tastants are known to relax airways completely. However, TAS2R135 or TAS2R126 agonists either failed to induce relaxation of pre-contracted airways in wild-type mice and Tas2r TKO mice or relaxed them dose-dependently, but to the same extent in both types of mice. These results indicate that TAS2Rs are not required for bitter tastant-induced bronchodilation. The Tas2r TKO mice also provide a valuable model to resolve whether TAS2Rs mediate bitter tastant-induced responses in many other extraoral tissues.
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Affiliation(s)
- Ping Lu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Mai K ElMallah
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Zeyu Liu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Chan Wu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jun Chen
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Lawrence M Lifshitz
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ronghua ZhuGe
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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12
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Sharma P, McAlinden KD, Ghavami S, Deshpande DA. Chloroquine: Autophagy inhibitor, antimalarial, bitter taste receptor agonist in fight against COVID-19, a reality check? Eur J Pharmacol 2021; 897:173928. [PMID: 33545161 PMCID: PMC7857018 DOI: 10.1016/j.ejphar.2021.173928] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 01/09/2023]
Abstract
The recent SARS-CoV-2 pandemic poses one of the greatest challenges to modern medicine. Therefore, identification of new therapeutic strategies seems essential either based on novel vaccines or drugs or simply repurposing existing drugs. Notably, due to their known safety profile, repurposing of existing drugs is the fastest and highly efficient approach to bring a therapeutic to a clinic for any new indication. One such drug that has been used extensively for decades is chloroquine (CQ, with its derivatives) either for malaria, lupus and rheumatoid arthritis. Accumulating body of evidence from experimental pharmacology suggests that CQ and related analogues also activate certain pathways that can potentially be exploited for therapeutic gain. For example, in the airways, this has opened an attractive avenue for developing novel bitter taste ligands as a new class of bronchodilators for asthma. While CQ and its derivatives have been proposed as a therapy in COVID-19, it remains to be seen whether it really work in the clinic? To this end, our perspective aims to provide a timely yet brief insights on the existing literature on CQ and the controversies surrounding its use in COVID-19. Further, we also highlight some of cell-based mechanism(s) that CQ and its derivatives affect in mediating variety of physiological responses in the cell. We believe, data emanating from the clinical studies and continual understanding of the fundamental mechanisms may potentially help in designing effective therapeutic strategies that meets both efficacy and safety criteria for COVID-19.
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Affiliation(s)
- Pawan Sharma
- Center for Translational Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
| | - Kielan D McAlinden
- Department of Laboratory Medicine, School of Health Sciences, University of Tasmania, Launceston, Tasmania, 7248, Australia
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Rady College of Medicine, Max Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
| | - Deepak A Deshpande
- Center for Translational Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
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Taha MA, Hall CA, Shortess CJ, Rathbone RF, Barham HP. Treatment Protocol for COVID-19 Based on T2R Phenotype. Viruses 2021; 13:v13030503. [PMID: 33803811 PMCID: PMC8003114 DOI: 10.3390/v13030503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 11/16/2022] Open
Abstract
COVID-19 has become a global pandemic of the highest priority. Multiple treatment protocols have been proposed worldwide with no definitive answer for acure. A prior retrospective study showed association between bitter taste receptor 38 (T2R38) phenotypes and the severity of COVID-19. Based on this, we proposed assessing the different T2R38 phenotypes response towards a targeted treatment protocol. Starting July 2020 till December 2020, we tested subjects for T2R38 phenotypic expression (supertasters, tasters, and nontasters). Subjects who were subsequently infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (diagnosed via PCR) were included. Based on their taster status, supertasters were given dexamethasone for 4 days; tasters were given azithromycin and dexamethasone +/− hydroxychloroquine for 7 days; and nontasters were given azithromycin and dexamethasone for 12 days. Subjects were followed prospectively and their outcomes were documented. Seven hundred forty-seven COVID-19 patients were included, with 184 (24.7%) supertasters, 371 (49.6%) tasters, and192 (25.7%) nontasters. The average duration of symptoms with the treatment protocol was 5 days for supertasters, 8.1 days for tasters, and 16.2 days for nontasters. Only three subjects (0.4%) required hospitalization (3/3 nontasters). Targeted treatment protocol showed significant correlation (p < 0.05) based on patients’ T2R38 phenotypic expression. Assessing treatment protocols for COVID-19 patients according to their T2R38 phenotype could provide insight into the inconsistent results obtained from the different studies worldwide. Further study is warranted on the categorization of patients based on their T2R38 phenotype.
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Affiliation(s)
- Mohamed A. Taha
- Rhinology and Skull Base Research Group, Baton Rouge General Medical Center, 8585 Picardy Ave., Suite 210, Baton Rouge, LA 70809, USA; (C.A.H.); (C.J.S.); (R.F.R.); (H.P.B.)
- Department of Otorhinolaryngology, Cairo University, Cairo 11451, Egypt
- Correspondence: ; Tel.: +1-225-819-1181; Fax: +1-225-246-8333
| | - Christian A. Hall
- Rhinology and Skull Base Research Group, Baton Rouge General Medical Center, 8585 Picardy Ave., Suite 210, Baton Rouge, LA 70809, USA; (C.A.H.); (C.J.S.); (R.F.R.); (H.P.B.)
- Sinus and Nasal Specialists of Louisiana, Baton Rouge, LA 70809, USA
| | - Colin J. Shortess
- Rhinology and Skull Base Research Group, Baton Rouge General Medical Center, 8585 Picardy Ave., Suite 210, Baton Rouge, LA 70809, USA; (C.A.H.); (C.J.S.); (R.F.R.); (H.P.B.)
| | - Richard F. Rathbone
- Rhinology and Skull Base Research Group, Baton Rouge General Medical Center, 8585 Picardy Ave., Suite 210, Baton Rouge, LA 70809, USA; (C.A.H.); (C.J.S.); (R.F.R.); (H.P.B.)
| | - Henry P. Barham
- Rhinology and Skull Base Research Group, Baton Rouge General Medical Center, 8585 Picardy Ave., Suite 210, Baton Rouge, LA 70809, USA; (C.A.H.); (C.J.S.); (R.F.R.); (H.P.B.)
- Sinus and Nasal Specialists of Louisiana, Baton Rouge, LA 70809, USA
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14
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Bloxham CJ, Foster SR, Thomas WG. A Bitter Taste in Your Heart. Front Physiol 2020; 11:431. [PMID: 32457649 PMCID: PMC7225360 DOI: 10.3389/fphys.2020.00431] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 04/08/2020] [Indexed: 12/11/2022] Open
Abstract
The human genome contains ∼29 bitter taste receptors (T2Rs), which are responsible for detecting thousands of bitter ligands, including toxic and aversive compounds. This sentinel function varies between individuals and is underpinned by naturally occurring T2R polymorphisms, which have also been associated with disease. Recent studies have reported the expression of T2Rs and their downstream signaling components within non-gustatory tissues, including the heart. Though the precise role of T2Rs in the heart remains unclear, evidence points toward a role in cardiac contractility and overall vascular tone. In this review, we summarize the extra-oral expression of T2Rs, focusing on evidence for expression in heart; we speculate on the range of potential ligands that may activate them; we define the possible signaling pathways they activate; and we argue that their discovery in heart predicts an, as yet, unappreciated cardiac physiology.
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Affiliation(s)
- Conor J Bloxham
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Simon R Foster
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Walter G Thomas
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
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15
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Zhu H, Liu L, Ren L, Chen J, Peng L, Shi C, Wang X, Hu S, Zhang C, Gu M, Li X. Bitter receptor member TAS2R4 may have neurobiological function beyond acting as a bitter receptor. Acta Biochim Biophys Sin (Shanghai) 2020; 52:460-462. [PMID: 32159211 DOI: 10.1093/abbs/gmaa003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/17/2020] [Accepted: 01/17/2020] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hongling Zhu
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Lianyong Liu
- Department of Endocrinology, Punan Hospital of Pudong New District, Shanghai 200125, China
| | - Li Ren
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Juan Chen
- Department of Obstetrics and Gynecology, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Li Peng
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Chao Shi
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Xing Wang
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Shuanggang Hu
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Center for Reproductive Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, China
| | - Chaobao Zhang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology (SIBCB), Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Mingjun Gu
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
| | - Xiangqi Li
- Department of Endocrine, Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200135, China
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16
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Zhu H, Liu L, Ren L, Ma J, Hu S, Zhu Z, Zhao X, Shi C, Wang X, Zhang C, Gu M, Li X. Systematic prediction of the biological functions of TAS2R10 using positive co-expression analysis. Exp Ther Med 2020; 19:1733-1738. [PMID: 32104227 PMCID: PMC7027137 DOI: 10.3892/etm.2019.8397] [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: 05/01/2019] [Accepted: 11/07/2019] [Indexed: 11/06/2022] Open
Abstract
Type 2 taste receptor 10 (TAS2R10), belonging to the TAS2R family of bitter receptors, is widely expressed in extra-oral tissues. However, its biological roles beyond bitterness sensing in the tongue have remained largely elusive. The present study aimed to perform a positive co-expression analysis using 60,000 Affymetrix expression arrays and 5,000 The Cancer Genome Atlas datasets to uncover such roles. Based on the functional enrichment analysis, it was indicated that in the Gene Ontology (GO) category biological process, TAS2R10 was mostly involved in 'cellular protein metabolic process', 'protein modification process', 'cellular protein modification process' and 'cellular component assembly'. In the GO category cellular component, the co-expressed genes were accumulated in 'Spt-Ada-Gcn5 acetyltransferase (SAGA)-type complex' and 'SAGA complex', and in the category molecular function, they were concentrated in 'hexosaminidase activity', 'cytoskeletal adaptor activity', 'cyclin binding' and 'β-N-acetylhexosaminidase activity'. Of note, it was indicated that TAS2R10 may be involved in 'ubiquitin-mediated proteolysis', which may provide a starting point to fully investigate the detailed functions of TAS2R10 in the future. TAS2R10 was also indicated to be associated with human diseases, i.e. 'Salmonella infection'. Overall, the present study was the first to perform a comprehensive bioinformatics analysis of the functions of TAS2R10 and provide insight regarding the notion that this gene may have crucial roles beyond bitterness sensing.
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Affiliation(s)
- Hongling Zhu
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Lianyong Liu
- Department of Endocrinology, Punan Hospital of Pudong New District, Shanghai 200125, P.R. China
| | - Li Ren
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Junhua Ma
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Shuanggang Hu
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Center for Reproductive Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, P.R. China
| | - Zhaohui Zhu
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Xuemei Zhao
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Chao Shi
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Xing Wang
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Chaobao Zhang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Mingjun Gu
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
| | - Xiangqi Li
- Department of Endocrinology, Shanghai Gongli Hospital, The Second Military Medical University, Shanghai 200135, P.R. China
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17
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Wang Q, Liszt KI, Depoortere I. Extra-oral bitter taste receptors: New targets against obesity? Peptides 2020; 127:170284. [PMID: 32092303 DOI: 10.1016/j.peptides.2020.170284] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/10/2020] [Accepted: 02/20/2020] [Indexed: 12/13/2022]
Abstract
Taste perception on the tongue is essential to help us to identify nutritious or potential toxic food substances. Emerging evidence has demonstrated the expression and function of bitter taste receptors (TAS2Rs) in a wide range of extra-oral tissues. In particular, TAS2Rs in gastrointestinal enteroendocrine cells control the secretion of appetite regulating gut hormones and influence hunger and food intake. Furthermore, these effects may be reinforced by the presence of TAS2Rs on intestinal smooth muscle cells, adipocytes and the brain. This review summarises how activation of extra-oral TAS2Rs can influence appetite and body weight control and how obesity impacts the expression and function of TAS2Rs. Region-selective targeting of bitter taste receptors may be promising targets for the treatment of obesity.
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Affiliation(s)
- Qiaoling Wang
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Kathrin I Liszt
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Inge Depoortere
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium.
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18
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Welcome MO. The bitterness of genitourinary infections: Properties, ligands of genitourinary bitter taste receptors and mechanisms linking taste sensing to inflammatory processes in the genitourinary tract. Eur J Obstet Gynecol Reprod Biol 2020; 247:101-110. [PMID: 32088528 DOI: 10.1016/j.ejogrb.2020.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 02/03/2020] [Accepted: 02/13/2020] [Indexed: 01/04/2023]
Abstract
BACKGROUND Though, first identified in the gastrointestinal tract, bitter taste receptors are now believed to be ubiquitously expressed in several regions of the body, including the respiratory tract, where they play a critical role in sensing and clearance of excess metabolic substrates, toxins, debris, and pathogens. More recently, bitter taste receptor expression has been reported in cells, tissues and organs of the genitourinary (GU) system, suggesting that these receptors may play an integral role in mediating inflammatory responses to microbial aggression in the GU tract. However, the mechanisms, linking bitter taste receptor sensing with inflammatory responses are not exactly clear. Here, I review recent data on the properties and ligands of bitter taste receptors and suggest mechanisms of bitter taste receptor signaling in the GU tract, and the molecular pathways that link taste sensing to inflammatory responses in GU tract. METHOD Computer-aided search was conducted in Scopus, PubMed, Web of Science and Google Scholar for relevant peer-reviewed articles published between 1990 and 2018, investigating the functional implication of bitter taste receptors in GU infections, using the following keywords: extra-oral bitter taste receptors, bitter taste receptors, GU bitter taste receptors, kidney OR renal OR ureteral OR urethral OR bladder OR detrusor smooth muscle OR testes OR spermatozoa OR prostate OR vaginal OR cervix OR ovarian OR endometrial OR myometrial OR placenta OR cutaneous bitter taste receptors. To identify research gaps on etiopathogenesis of GU infections/inflammation, additional search was conducted using the following keywords: GU inflammatory signaling, GU microbes, GU bacteria, GU virus, GU protozoa, GU microbial metabolites, and GU infection. The retrieved articles were filtered and further screened for relevance according to the aim of the study. A narrative review was performed for selected literatures. RESULTS Bitter taste receptors of the GU tract may constitute essential components of the pathogenetic mechanisms of GU infections/inflammation that are activated by microbial components, known as quorum sensing signal molecules. Based on accumulating evidences, indicating that taste receptors may signal downstream to activate inflammatory cascades, in addition to the nitric oxide-induced microbicidal effects produced upon taste receptor activation, it is suggested that the anti-inflammatory activities of bitter taste receptor stimulation are mediated via pathways involving the nuclear factor κB by downstream signaling of the metabolic and stress sensors, adenosine monophosphate-activated protein kinase and nicotinamide adenine dinucleotide-dependent silent mating type information regulation 2 homolog 1 (sirtuin 1), resulting to the synthesis of anti-inflammatory cytokines/chemokines, and antimicrobial factors, which ultimately, under normal conditions, leads to the elimination of microbial aggression. CONCLUSIONS GU bitter taste receptors may represent critical players in GU tract infections/inflammation. Bitter taste receptors may serve as important therapeutic target for treatment of a number of infectious diseases that affect the GU tract.
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Affiliation(s)
- Menizibeya O Welcome
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Nile University of Nigeria, Abuja, Nigeria.
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19
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Liu M, Qian W, Subramaniyam S, Liu S, Xin W. Denatonium enhanced the tone of denuded rat aorta via bitter taste receptor and phosphodiesterase activation. Eur J Pharmacol 2020; 872:172951. [PMID: 32006560 DOI: 10.1016/j.ejphar.2020.172951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 01/15/2020] [Accepted: 01/24/2020] [Indexed: 11/27/2022]
Abstract
Bitter taste receptors (Tas2rs) initiate a bitter taste signaling involving the activation of taste-specific G protein gustducin and phosphodiesterases (PDEs); it leads to the decrease of cytosolic level of cyclic adenosine monophosphate (cAMP) in taste cells. Recent studies have identified the expression of Tas2rs in a variety of non-lingual tissues including vascular smooth muscle (VSM), pulmonary smooth muscle and airway smooth muscle. The current study aims to determine the expression of Tas2rs and gustducin in rat aortic smooth muscle tissue and to investigate the effect of Tas2rs agonist denatonium on the tone of isolated denuded aorta rings. Here we reported the expression of six subtypes of Tas2r mRNA and the taste receptor-associated G proteins in endothelium-denuded aorta. Immunostaining experiments showed that the protein of gustducin expressed in vascular smooth muscle cells (VSMCs). Furthermore, denatonium increased the tone of freshly isolated denuded aorta rings in a concentration-dependent manner, and the potentiation effect of denatonium was blocked by a Tas2rs antagonist adenosine 5'-monophosphate (5'-AMP), by the cAMP-hydrolyzing PDE inhibitors, and by a cAMP-synthesizing enzyme activator forskolin, respectively. The blockade of Gβγ signaling did not have a negative impact on the denatonium-induced tonic contractions. These findings suggested that the functional Tas2rs and gustducin are expressed in rat aortic smooth muscle and that denatonium might increase the smooth muscle tone through a Tas2rs signaling pathway involving the activation of PDEs.
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Affiliation(s)
- Minchi Liu
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Wenjun Qian
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | | | - Shuang Liu
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Wenkuan Xin
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, China; College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China.
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20
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Zhang Q, Tsuji-Hosokawa A, Willson C, Watanabe M, Si R, Lai N, Wang Z, Yuan JXJ, Wang J, Makino A. Chloroquine differentially modulates coronary vasodilation in control and diabetic mice. Br J Pharmacol 2020; 177:314-327. [PMID: 31503328 DOI: 10.1111/bph.14864] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE Chloroquine is a traditional medicine to treat malaria. There is increasing evidence that chloroquine not only induces phagocytosis but regulates vascular tone. Few reports investigating the effect of chloroquine on vascular responsiveness of coronary arteries have been made. In this study, we examined how chloroquine affected endothelium-dependent relaxation in coronary arteries under normal and diabetic conditions. EXPERIMENTAL APPROACH We isolated coronary arteries from mice and examined endothelium-dependent relaxation (EDR). Human coronary endothelial cells and mouse coronary endothelial cells isolated from control and diabetic mouse (TALLYHO/Jng [TH] mice, a spontaneous type 2 diabetic mouse model) were used for the molecular biological or cytosolic NO and Ca2+ measurements. KEY RESULTS Chloroquine inhibited endothelium-derived NO-dependent relaxation but had negligible effect on endothelium-derived hyperpolarization (EDH)-dependent relaxation in coronary arteries of control mice. Chloroquine significantly decreased NO production in control human coronary endothelial cells partly by phosphorylating eNOSThr495 (an inhibitory phosphorylation site of eNOS) and attenuating the rise of cytosolic Ca2+ concentration after stimulation. EDR was significantly inhibited in diabetic mice in comparison to control mice. Interestingly, chloroquine enhanced EDR in diabetic coronary arteries by, specifically, increasing EDH-dependent relaxation due partly to its augmenting effect on gap junction activity in diabetic mouse coronary endothelial cells. CONCLUSIONS AND IMPLICATIONS These data indicate that chloroquine affects vascular relaxation differently under normal and diabetic conditions. Therefore, the patients' health condition such as coronary macrovascular or microvascular disease, with or without diabetes, must be taken account into the consideration when selecting chloroquine for the treatment of malaria.
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Affiliation(s)
- Qian Zhang
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Physiology, The University of Arizona, Tucson, Arizona.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | | | - Conor Willson
- Department of Physiology, The University of Arizona, Tucson, Arizona
| | - Makiko Watanabe
- Department of Physiology, The University of Arizona, Tucson, Arizona
| | - Rui Si
- Department of Physiology, The University of Arizona, Tucson, Arizona
| | - Ning Lai
- Department of Medicine, University of California, San Diego, La Jolla, California.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ziyi Wang
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Medicine, The University of Arizona, Tucson, Arizona.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jason X-J Yuan
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Medicine, The University of Arizona, Tucson, Arizona
| | - Jian Wang
- Department of Medicine, The University of Arizona, Tucson, Arizona.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ayako Makino
- Department of Medicine, University of California, San Diego, La Jolla, California.,Department of Physiology, The University of Arizona, Tucson, Arizona.,Department of Medicine, The University of Arizona, Tucson, Arizona
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21
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The senses of the choroid plexus. Prog Neurobiol 2019; 182:101680. [DOI: 10.1016/j.pneurobio.2019.101680] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/26/2019] [Accepted: 08/01/2019] [Indexed: 12/12/2022]
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22
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Luo M, Ni K, Jin Y, Yu Z, Deng L. Toward the Identification of Extra-Oral TAS2R Agonists as Drug Agents for Muscle Relaxation Therapies via Bioinformatics-Aided Screening of Bitter Compounds in Traditional Chinese Medicine. Front Physiol 2019; 10:861. [PMID: 31379593 PMCID: PMC6647893 DOI: 10.3389/fphys.2019.00861] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/20/2019] [Indexed: 12/29/2022] Open
Abstract
Significant advances have been made in the past decade in mapping the distributions and the physiological functions of extra-oral bitter taste receptors (TAS2Rs) in non-gustatory tissues. In particular, it has been found that TAS2Rs are expressed in various muscle tissues and activation of TAS2Rs can lead to muscle cell relaxation, which suggests that TAS2Rs may be important new targets in muscle relaxation therapy for various muscle-related diseases. So far, however, there is a lack of potent extra-oral TAS2R agonists that can be used as novel drug agents in muscle relaxation therapies. Interestingly, traditional Chinese medicine (TCM) often characterizes a drug’s property in terms of five distinct flavors (bitter, sweet, sour, salty, and pungent) according to its taste and function, and commonly regards “bitterness” as an intrinsic property of “good medicine.” In addition, many bitter flavored TCM are known in practice to cause muscle relaxation after long term use, and in lab experiments the compounds identified from some bitter flavored TCM do activate TAS2Rs and thus relax muscle cells. Therefore, it is highly possible to discover very useful extra-oral TAS2R agonists for muscle relaxation therapies among the abundant bitter compounds used in bitter flavored TCM. With this perspective, we reviewed in literature the distribution of TAS2Rs in different muscle systems with a focus on the map of bitter flavored TCM which can regulate muscle contractility and related functional chemical components. We also reviewed the recently established databases of TCM chemical components and the bioinformatics software which can be used for high-throughput screening and data mining of the chemical components associated with bitter flavored TCM. All together, we aim to present a knowledge-based approach and technological platform for identification or discovery of extra-oral TAS2R agonists that can be used as novel drug agents for muscle relaxation therapies through screening and evaluation of chemical compounds used in bitter flavored TCM.
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Affiliation(s)
- Mingzhi Luo
- Changzhou Key Laboratory of Respiratory Medical Engineering, Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China
| | - Kai Ni
- Changzhou Key Laboratory of Respiratory Medical Engineering, Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China
| | - Yang Jin
- Bioengineering College, Chongqing University, Chongqing, China
| | - Zifan Yu
- Changzhou Key Laboratory of Respiratory Medical Engineering, Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China
| | - Linhong Deng
- Changzhou Key Laboratory of Respiratory Medical Engineering, Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China
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23
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Jaggupilli A, Howard R, Aluko RE, Chelikani P. Advanced Glycation End-Products Can Activate or Block Bitter Taste Receptors. Nutrients 2019; 11:nu11061317. [PMID: 31212814 PMCID: PMC6628017 DOI: 10.3390/nu11061317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022] Open
Abstract
Bitter taste receptors (T2Rs) are expressed in several tissues of the body and are involved in a variety of roles apart from bitter taste perception. Advanced glycation end-products (AGEs) are produced by glycation of amino acids in proteins. There are varying sources of AGEs, including dietary food products, as well as endogenous reactions within our body. Whether these AGEs are T2R ligands remains to be characterized. In this study, we selected two AGEs, namely, glyoxal-derived lysine dimer (GOLD) and carboxymethyllysine (CML), based on their predicted interaction with the well-studied T2R4, and its physiochemical properties. Results showed predicted binding affinities (Kd) for GOLD and CML towards T2R4 in the nM and μM range, respectively. Calcium mobilization assays showed that GOLD inhibited quinine activation of T2R4 with IC50 10.52 ± 4.7 μM, whilst CML was less effective with IC50 32.62 ± 9.5 μM. To characterize whether this antagonism was specific to quinine activated T2R4 or applicable to other T2Rs, we selected T2R14 and T2R20, which are expressed at significant levels in different human tissues. A similar effect of GOLD was observed with T2R14; and in contrast, GOLD and CML activated T2R20 with an EC50 of 79.35 ± 29.16 μM and 65.31 ± 17.79 μM, respectively. In this study, we identified AGEs as novel T2R ligands that caused either activation or inhibition of different T2Rs.
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Affiliation(s)
- Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada.
| | - Ryan Howard
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada.
| | - Rotimi E Aluko
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada.
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24
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Glendinning JI. Oral Post-Oral Actions of Low-Calorie Sweeteners: A Tale of Contradictions and Controversies. Obesity (Silver Spring) 2018; 26 Suppl 3:S9-S17. [PMID: 30290077 DOI: 10.1002/oby.22253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/28/2018] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Many scientists and laypeople alike have concerns about low-calorie sweeteners (LCSs). These concerns stem from both a dissatisfaction with the taste of LCSs and reports that they cause metabolic disruptions (e.g., weight gain, glucose intolerance). METHODS This article provides a critical review of the literature on LCSs from the standpoint of their taste, gastrointestinal, and metabolic effects; biological fate in the body; and impact on ingestion and glucose homeostasis. RESULTS AND CONCLUSIONS Mammals can readily discriminate between LCSs and sugars because both types of sweetener activate distinct oral and post-oral sensory pathways. LCSs differ in their ability to access post-oral tissues, but few studies have incorporated this observation into their design. It is difficult to extrapolate results between mice, rats, and humans because of interspecies differences in the taste and post-oral actions of LCSs and the fact that investigators often use different response measures in rodents and humans. There is confounding in the experimental design of some of the most widely cited studies of LCS-induced metabolic disruptions. The uncritical acceptance of these studies has generated considerable controversy. More work is needed to obtain a clearer understanding of the metabolic effects of LCSs.
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Affiliation(s)
- John I Glendinning
- Department of Biology, Barnard College, Columbia University, New York, New York, USA
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25
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Dragos D, Gilca M. Taste of phytocompounds: A better predictor for ethnopharmacological activities of medicinal plants than the phytochemical class? JOURNAL OF ETHNOPHARMACOLOGY 2018; 220:129-146. [PMID: 29604378 DOI: 10.1016/j.jep.2018.03.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 03/26/2018] [Accepted: 03/26/2018] [Indexed: 05/27/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Understanding the patterns that shape traditional medical knowledge is essential for accelerating ethnopharmacological progress. According to Ayurveda, medicinal plants that belong to different taxa, but which have similar taste, may display similar (ethno)pharmacological activities (EPAs) (Bhishagratna, 1998; Sharma and Dash, 2006). AIM OF THE STUDY To understand the patterns that govern the distribution of herbal EPAs in Ayurveda and to evaluate the potential concordance between chemical class or taste of the constituent phytocompounds and EPAs. MATERIAL AND METHODS A mixed database (PhytoMolecularTasteDB) was constructed for Ayurvedic medicinal plants by integrating modern data (medicinal plant composition, phytochemical taste) with traditional data (ethnopharmacological activities of plant). PhytoMolecularTasteDB contains 431 Ayurvedic medicinal plants, 94 EPAs, 223 chemical classes of phytocompounds and 438 herbal tastants. Potential global or individual associations between chemical classes/taste of the phytoconstituents and EPAs were statistically analyzed. RESULTS There was no global statistical correlation between the various chemical classes of phytocompounds and EPAs, although there were several individual correlations. The results suggest the existence of a global statistical correlation (besides several individual correlations) between the plant "molecular taste" (various taste-based classes of phytocompounds) and EPAs. CONCLUSIONS These results suggest that phytochemical taste may be more relevant than chemical class for EPAs prediction.
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Affiliation(s)
- Dorin Dragos
- Medical Semiology Dept., Faculty of General Medicine, Carol Davila University of Medicine and Pharmacy, B-dul Eroilor Sanitari nr.8, 050471 Bucharest, Romania; Nephrology Clinic, University Emergency Hospital Bucharest, Bucharest, Romania.
| | - Marilena Gilca
- Biochemistry Dept., Faculty of General Medicine, Carol Davila University of Medicine and Pharmacy, B-dul Eroilor Sanitari nr.8, 050471 Bucharest, Romania.
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26
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Abstract
Nutrient-sensing mechanisms have emerged as the fringe articulating nutritional needs with dietary choices. Carbohydrate, amino acid, fatty acid, mineral, and water-sensing receptors are highly conserved across mammals and birds, consisting of a repertoire of 22 genes known to date. In contrast, bitter receptors are highly divergent and have a high incidence of polymorphisms within and between mammals and birds and are involved in the adaptation of species to specific environments. In addition, the expression of nutrient-sensing genes outside the oral cavity seems to mediate the required decision-making dialogue between the gut and the brain by translating exogenous chemical stimuli into neuronal inputs, and vice versa, to translate the endogenous signals relevant to the nutritional status into specific appetites and the control of feed intake. The relevance of these sensors in nondigestive systems has uncovered fascinating potential as pharmacological targets relevant to respiratory and cardiovascular diseases.
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Affiliation(s)
- Eugeni Roura
- Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, and School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Simon R. Foster
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark
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27
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Stern L, Giese N, Hackert T, Strobel O, Schirmacher P, Felix K, Gaida MM. Overcoming chemoresistance in pancreatic cancer cells: role of the bitter taste receptor T2R10. J Cancer 2018; 9:711-725. [PMID: 29556329 PMCID: PMC5858493 DOI: 10.7150/jca.21803] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/26/2017] [Indexed: 12/14/2022] Open
Abstract
Bitter taste receptors (T2Rs) are G-protein coupled transmembrane proteins initially identified in the gustatory system as sensors for the taste of bitter. Recent evidence on expression of these receptors outside gustatory tissues suggested alternative functions, and there is growing interest of their potential role in cancer biology. In this study, we report for the first time, expression and functionality of the bitter receptor family member T2R10 in both human pancreatic ductal adenocarcinoma (PDAC) tissue and PDAC derived cell lines. Caffeine, a known ligand for T2R10, rendered the tumor cells more susceptible to two standard chemotherapeutics, Gemcitabine and 5-Fluoruracil. Knocking down T2R10 in the cell line BxPC-3 reduced the caffeine-induced effect. As possible underlying mechanism, we found that caffeine via triggering T2R10 inhibited Akt phosphorylation and subsequently downregulated expression of ABCG2, the so-called multi-drug resistance protein that participates in rendering cells resistant to a variety of chemotherapeutics. In conclusion, T2R10 is expressed in pancreatic cancer and it downmodulates the chemoresistance of the tumor cells.
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Affiliation(s)
- Louisa Stern
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Nathalia Giese
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Thilo Hackert
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Oliver Strobel
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Peter Schirmacher
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
| | - Klaus Felix
- Department of General, Visceral and Transplantation Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias M Gaida
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
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28
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Liu S, Lu S, Xu R, Atzberger A, Günther S, Wettschureck N, Offermanns S. Members of Bitter Taste Receptor Cluster Tas2r143/Tas2r135/Tas2r126 Are Expressed in the Epithelium of Murine Airways and Other Non-gustatory Tissues. Front Physiol 2017; 8:849. [PMID: 29163195 PMCID: PMC5670347 DOI: 10.3389/fphys.2017.00849] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/11/2017] [Indexed: 11/13/2022] Open
Abstract
The mouse bitter taste receptors Tas2r143, Tas2r135, and Tas2r126 are encoded by genes that cluster on chromosome 6 and have been suggested to be expressed under common regulatory elements. Previous studies indicated that the Tas2r143/Tas2r135/Tas2r126 cluster is expressed in the heart, but other organs had not been systematically analyzed. In order to investigate the expression of this bitter taste receptor gene cluster in non-gustatory tissues, we generated a BAC (bacterial artificial chromosome) based transgenic mouse line, expressing CreERT2 under the control of the Tas2r143 promoter. After crossing this line with a mouse line expressing EGFP after Cre-mediated recombination, we were able to validate the Tas2r143-CreERT2 transgenic mouse line and monitor the expression of Tas2r143. EGFP-positive cells, indicating expression of members of the cluster, were found in about 47% of taste buds, and could also be found in several other organs. A population of EGFP-positive cells was identified in thymic epithelial cells, in the lamina propria of the intestine and in vascular smooth muscle cells of cardiac blood vessels. EGFP-positive cells were also identified in the epithelium of organs readily exposed to pathogens including lower airways, the gastrointestinal tract, urethra, vagina, and cervix. With respect to the function of cells expressing this bitter taste receptor cluster, RNA-seq analysis in EGFP-positive cells isolated from the epithelium of trachea and stomach showed expression of genes related to innate immunity. These data further support the concept that bitter taste receptors serve functions outside the gustatory system.
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Affiliation(s)
- Shuya Liu
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Shun Lu
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Rui Xu
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Ann Atzberger
- Flow Cytometry Service Facility, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Günther
- ECCPS Bioinformatics and Deep Sequencing Platform, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Nina Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Medical Faculty, Goethe University Frankfurt, Frankfurt, Germany
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.,Medical Faculty, Goethe University Frankfurt, Frankfurt, Germany
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29
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Wu K, Zhang Q, Wu X, Lu W, Tang H, Liang Z, Gu Y, Song S, Ayon RJ, Wang Z, McDermott KM, Balistrieri A, Wang C, Black SM, Garcia JGN, Makino A, Yuan JXJ, Wang J. Chloroquine is a potent pulmonary vasodilator that attenuates hypoxia-induced pulmonary hypertension. Br J Pharmacol 2017; 174:4155-4172. [PMID: 28849593 DOI: 10.1111/bph.13990] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 08/09/2017] [Accepted: 08/14/2017] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Sustained pulmonary vasoconstriction and excessive pulmonary vascular remodelling are two major causes of elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension. The purpose of this study was to investigate whether chloroquine induced relaxation in the pulmonary artery (PA) and attenuates hypoxia-induced pulmonary hypertension (HPH). EXPERIMENTAL APPROACH Isometric tension was measured in rat PA rings pre-constricted with phenylephrine or high K+ solution. PA pressure was measured in mouse isolated, perfused and ventilated lungs. Fura-2 fluorescence microscopy was used to measure cytosolic free Ca2+ concentration levels in PA smooth muscle cells (PASMCs). Patch-clamp experiments were performed to assess the activity of voltage-dependent Ca2+ channels (VDCCs) in PASMC. Rats exposed to hypoxia (10% O2 ) for 3 weeks were used as the model of HPH or Sugen5416/hypoxia (SuHx) for in vivo experiments. KEY RESULTS Chloroquine attenuated agonist-induced and high K+ -induced contraction in isolated rat PA. Pretreatment with l-NAME or indomethacin and functional removal of endothelium failed to inhibit chloroquine-induced PA relaxation. In PASMC, extracellular application of chloroquine attenuated store-operated Ca2+ entry and ATP-induced Ca2+ entry. Furthermore, chloroquine also inhibited whole-cell Ba2+ currents through VDCC in PASMC. In vivo experiments demonstrated that chloroquine treatment ameliorated the HPH and SuHx models. CONCLUSIONS AND IMPLICATIONS Chloroquine is a potent pulmonary vasodilator that may directly or indirectly block VDCC, store-operated Ca2+ channels and receptor-operated Ca2+ channels in PASMC. The therapeutic potential of chloroquine in pulmonary hypertension is probably due to the combination of its vasodilator, anti-proliferative and anti-autophagic effects.
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Affiliation(s)
- Kang Wu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Qian Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Xiongting Wu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wenju Lu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Haiyang Tang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Zhihao Liang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yali Gu
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Shanshan Song
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Ramon J Ayon
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Ziyi Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Kimberly M McDermott
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Angela Balistrieri
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Christina Wang
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Stephen M Black
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Joe G N Garcia
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Ayako Makino
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Jason X-J Yuan
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Physiology, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Jian Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA.,Department of Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
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30
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Fierro F, Suku E, Alfonso-Prieto M, Giorgetti A, Cichon S, Carloni P. Agonist Binding to Chemosensory Receptors: A Systematic Bioinformatics Analysis. Front Mol Biosci 2017; 4:63. [PMID: 28932739 PMCID: PMC5592726 DOI: 10.3389/fmolb.2017.00063] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/22/2017] [Indexed: 12/17/2022] Open
Abstract
Human G-protein coupled receptors (hGPCRs) constitute a large and highly pharmaceutically relevant membrane receptor superfamily. About half of the hGPCRs' family members are chemosensory receptors, involved in bitter taste and olfaction, along with a variety of other physiological processes. Hence these receptors constitute promising targets for pharmaceutical intervention. Molecular modeling has been so far the most important tool to get insights on agonist binding and receptor activation. Here we investigate both aspects by bioinformatics-based predictions across all bitter taste and odorant receptors for which site-directed mutagenesis data are available. First, we observe that state-of-the-art homology modeling combined with previously used docking procedures turned out to reproduce only a limited fraction of ligand/receptor interactions inferred by experiments. This is most probably caused by the low sequence identity with available structural templates, which limits the accuracy of the protein model and in particular of the side-chains' orientations. Methods which transcend the limited sampling of the conformational space of docking may improve the predictions. As an example corroborating this, we review here multi-scale simulations from our lab and show that, for the three complexes studied so far, they significantly enhance the predictive power of the computational approach. Second, our bioinformatics analysis provides support to previous claims that several residues, including those at positions 1.50, 2.50, and 7.52, are involved in receptor activation.
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Affiliation(s)
- Fabrizio Fierro
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum JülichJülich, Germany
| | - Eda Suku
- Department of Biotechnology, University of VeronaVerona, Italy
| | - Mercedes Alfonso-Prieto
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum JülichJülich, Germany.,Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, Heinrich Heine University DüsseldorfDüsseldorf, Germany
| | - Alejandro Giorgetti
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum JülichJülich, Germany.,Department of Biotechnology, University of VeronaVerona, Italy
| | - Sven Cichon
- Institute of Neuroscience and Medicine INM-1, Forschungszentrum JülichJülich, Germany.,Institute for Human Genetics, Department of Genomics, Life&Brain Center, University of BonnBonn, Germany.,Division of Medical Genetics, Department of Biomedicine, University of BaselBasel, Switzerland
| | - Paolo Carloni
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum JülichJülich, Germany.,Department of Physics, Rheinisch-Westfälische Technische Hochschule AachenAachen, Germany.,VNU Key Laboratory "Multiscale Simulation of Complex Systems", VNU University of Science, Vietnam National UniversityHanoi, Vietnam
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31
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Pan S, Sharma P, Shah SD, Deshpande DA. Bitter taste receptor agonists alter mitochondrial function and induce autophagy in airway smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2017; 313:L154-L165. [PMID: 28450286 DOI: 10.1152/ajplung.00106.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 12/18/2022] Open
Abstract
Airway remodeling, including increased airway smooth muscle (ASM) mass, is a hallmark feature of asthma and COPD. We previously identified the expression of bitter taste receptors (TAS2Rs) on human ASM cells and demonstrated that known TAS2R agonists could promote ASM relaxation and bronchodilation and inhibit mitogen-induced ASM growth. In this study, we explored cellular mechanisms mediating the antimitogenic effect of TAS2R agonists on human ASM cells. Pretreatment of ASM cells with TAS2R agonists chloroquine and quinine resulted in inhibition of cell survival, which was largely reversed by bafilomycin A1, an autophagy inhibitor. Transmission electron microscope studies demonstrated the presence of double-membrane autophagosomes and deformed mitochondria. In ASM cells, TAS2R agonists decreased mitochondrial membrane potential and increased mitochondrial ROS and mitochondrial fragmentation. Inhibiting dynamin-like protein 1 (DLP1) reversed TAS2R agonist-induced mitochondrial membrane potential change and attenuated mitochondrial fragmentation and cell death. Furthermore, the expression of mitochondrial protein BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) and mitochondrial localization of DLP1 were significantly upregulated by TAS2R agonists. More importantly, inhibiting Bnip3 mitochondrial localization by dominant-negative Bnip3 significantly attenuated cell death induced by TAS2R agonist. Collectively the TAS2R agonists chloroquine and quinine modulate mitochondrial structure and function, resulting in ASM cell death. Furthermore, Bnip3 plays a central role in TAS2R agonist-induced ASM functional changes via a mitochondrial pathway. These findings further establish the cellular mechanisms of antimitogenic effects of TAS2R agonists and identify a novel class of receptors and pathways that can be targeted to mitigate airway remodeling as well as bronchoconstriction in obstructive airway diseases.
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Affiliation(s)
- Shi Pan
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Pawan Sharma
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sushrut D Shah
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Deepak A Deshpande
- Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania
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32
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Chen JG, Ping NN, Liang D, Li MY, Mi YN, Li S, Cao L, Cai Y, Cao YX. The expression of bitter taste receptors in mesenteric, cerebral and omental arteries. Life Sci 2017; 170:16-24. [DOI: 10.1016/j.lfs.2016.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 11/15/2022]
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Lu P, Zhang CH, Lifshitz LM, ZhuGe R. Extraoral bitter taste receptors in health and disease. J Gen Physiol 2017; 149:181-197. [PMID: 28053191 PMCID: PMC5299619 DOI: 10.1085/jgp.201611637] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/06/2016] [Accepted: 12/19/2016] [Indexed: 12/24/2022] Open
Abstract
Bitter taste receptors (TAS2Rs or T2Rs) belong to the superfamily of seven-transmembrane G protein-coupled receptors, which are the targets of >50% of drugs currently on the market. Canonically, T2Rs are located in taste buds of the tongue, where they initiate bitter taste perception. However, accumulating evidence indicates that T2Rs are widely expressed throughout the body and mediate diverse nontasting roles through various specialized mechanisms. It has also become apparent that T2Rs and their polymorphisms are associated with human disorders. In this review, we summarize the physiological and pathophysiological roles that extraoral T2Rs play in processes as diverse as innate immunity and reproduction, and the major challenges in this emerging field.
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Affiliation(s)
- Ping Lu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605
| | - Cheng-Hai Zhang
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605
| | - Lawrence M Lifshitz
- Biomedical Imaging Group, University of Massachusetts Medical School, Worcester, MA 01605.,Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Ronghua ZhuGe
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605 .,Biomedical Imaging Group, University of Massachusetts Medical School, Worcester, MA 01605
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Yu B, Cai W, Zhang HH, Zhong YS, Fang J, Zhang WY, Mo L, Wang LC, Yu CH. Selaginella uncinata flavonoids ameliorated ovalbumin-induced airway inflammation in a rat model of asthma. JOURNAL OF ETHNOPHARMACOLOGY 2017; 195:71-80. [PMID: 27916586 DOI: 10.1016/j.jep.2016.11.049] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 11/06/2016] [Accepted: 11/30/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Selaginella uncinata (Desv.) Spring, known as "Cuiyuncao", is a perennial herb widely distributed in the Southeast Asian countries. In the folk medicine, the local minority commonly use it to treat cough and asthma for centuries. AIM OF THE STUDY This study was carried out to investigate the protective mechanisms of total flavonoids from S. uncinata (SUF) on airway hyperresponsiveness, cytokine release and bitter taste receptors (T2Rs) signaling with emphasis on inflammatory responses in a rat model of ovalbumin (OVA)-induced asthma. MATERIALS AND METHODS Rats were sensitized and challenged with OVA to induce typical asthmatic reactions. Pathological changes of lung tissue were examined by HE staining. The serum levels of T cell-associated cytokines (IFN-γ, IL-4, IL-5 and IL-13), total IgE and OVA-specific IgE were determined by enzyme-linked immunosorbent assay (ELISA). Gene expressions of T2R10, IP3R1 and Orai1 in lung tissue were assayed by fluorescence quantitative real-time polymerase chain reaction (FQ-PCR) while protein expressions of NFAT1 and c-Myc were assayed by western blot analysis. The activation of SUF was investigated on tansgentic T2R10-GFP HEK293 cells. RESULTS SUF treatment attenuated airway hyperresponsiveness and goblet cell hyperplasia compared with OVA-challenged asthmatic rats. The serum levels of IL-4, IL-5 and IL-13 as well as total and OVA-specific IgE were decreased while serum IFN-γ was increased in SUF-treated rats. SUF treatment significantly up-regulated T2R10 gene expression, down-regulated IP3R1 and Orai1 gene expression. SUF further suppressed eotaxin, NFAT1 and c-Myc protein expression in lung tissues of OVA-challenged rats. CONCLUSIONS These results imply that SUF exerts anti-inflammatory function through the T2R10/IP3R1/NFAT1 dependent signaling pathway, and may warrant further evaluation as a possible agent for the treatment of asthma.
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Affiliation(s)
- Bing Yu
- College of Pharmacy, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Wei Cai
- Department of Traditional Chinese Medicine, Zhejiang Pharmaceutical College, Ningbo 315100, China
| | - Huan-Huan Zhang
- Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Yu-Sen Zhong
- Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Jie Fang
- Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Wen-You Zhang
- Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Li Mo
- College of Pharmacy, Zhejiang Chinese Medical University, Hangzhou 310053, China; Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Lu-Chen Wang
- College of Pharmacy, Zhejiang Chinese Medical University, Hangzhou 310053, China; Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Chen-Huan Yu
- Key Laboratory of Experimental Animal and Safety Evaluation, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China.
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Zhang YX, Wang X, Wang SF, Zhang YL, Qiao YJ. Traditional Chinese Bitter Flavor theory: Is there any relation with taste type II receptors? Eur J Integr Med 2016. [DOI: 10.1016/j.eujim.2016.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Larsson OJ, Manson ML, Starkhammar M, Fuchs B, Adner M, Kumlien Georén S, Cardell LO. The TLR7 agonist imiquimod induces bronchodilation via a nonneuronal TLR7-independent mechanism: a possible role for quinoline in airway dilation. Am J Physiol Lung Cell Mol Physiol 2016; 310:L1121-9. [PMID: 27084847 DOI: 10.1152/ajplung.00288.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/07/2016] [Indexed: 11/22/2022] Open
Abstract
Toll-like receptor (TLR) 7 agonists are known to reduce allergic airway inflammation. Their recently reported ability to rapidly relax airways has further increased their interest in the treatment of pulmonary disease. However, the mechanisms behind this effect are not fully understood. The present study, therefore, aimed to determine whether airway smooth muscle (ASM)-dependent mechanisms could be identified. TLR7 agonists were added to guinea pig airways following precontraction with carbachol in vitro or histamine in vivo. Pharmacological inhibitors were used to dissect conventional pathways of bronchodilation; tetrodotoxin was used or bilateral vagotomy was performed to assess neuronal involvement. Human ASM cells (HASMCs) were employed to determine the effect of TLR7 agonists on intracellular Ca(2+) ([Ca(2+)]i) mobilization. The well-established TLR7 agonist imiquimod rapidly relaxed precontracted airways in vitro and in vivo. This relaxation was demonstrated to be independent of nitric oxide, carbon monoxide, and cAMP signaling, as well as neuronal activity. A limited role for prostanoids could be detected. Imiquimod induced [Ca(2+)]i release from endoplasmic reticulum stores in HASMCs, inhibiting histamine-induced [Ca(2+)]i The TLR7 antagonist IRS661 failed to inhibit relaxation, and the structurally dissimilar agonist CL264 did not relax airways or inhibit [Ca(2+)]i This study shows that imiquimod acts directly on ASM to induce bronchorelaxation, via a TLR7-independent release of [Ca(2+)]i The effect is paralleled by other bronchorelaxant compounds, like chloroquine, which, like imiquimod, but unlike CL264, contains the chemical structure quinoline. Compounds with quinoline moieties may be of interest in the development of multifunctional drugs to treat pulmonary disease.
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Affiliation(s)
- Olivia J Larsson
- Division of ENT Diseases, CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Martijn L Manson
- Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden; and Institute for Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Magnus Starkhammar
- Division of ENT Diseases, CLINTEC, Karolinska Institutet, Stockholm, Sweden; Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden; and
| | - Barbara Fuchs
- Division of ENT Diseases, CLINTEC, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Adner
- Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden; and Institute for Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Susanna Kumlien Georén
- Division of ENT Diseases, CLINTEC, Karolinska Institutet, Stockholm, Sweden; Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden; and
| | - Lars-Olaf Cardell
- Division of ENT Diseases, CLINTEC, Karolinska Institutet, Stockholm, Sweden; Department of ENT Disease, Karolinska University Hospital, Stockholm, Sweden;
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Avau B, Depoortere I. The bitter truth about bitter taste receptors: beyond sensing bitter in the oral cavity. Acta Physiol (Oxf) 2016; 216:407-20. [PMID: 26493384 DOI: 10.1111/apha.12621] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/28/2015] [Accepted: 10/14/2015] [Indexed: 11/26/2022]
Abstract
The bitter taste receptor (TAS2R)-family of G-protein-coupled receptors has been identified on the tongue as detectors of bitter taste over a decade ago. In the last few years, they have been discovered in an ever growing number of extra-oral tissues, including the airways, the gut, the brain and even the testis. In tissues that contact the exterior, protective functions for TAS2Rs have been proposed, in analogy to their function on the tongue as toxicity detector. However, TAS2Rs have also been found in internal organs, suggesting other roles for these receptors, perhaps involving as yet unidentified endogenous ligands. The current review gives an overview of the different proposed functions for TAS2Rs in tissues other than the oral cavity; from appetite regulation to the treatment of asthma, regulation of gastrointestinal motility and control of airway innate immunity.
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Affiliation(s)
- B. Avau
- Translational Research Center for Gastrointestinal Disorders (TARGID); Gut Peptide Research Lab; University of Leuven; Leuven Belgium
| | - I. Depoortere
- Translational Research Center for Gastrointestinal Disorders (TARGID); Gut Peptide Research Lab; University of Leuven; Leuven Belgium
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Shaik FA, Singh N, Arakawa M, Duan K, Bhullar RP, Chelikani P. Bitter taste receptors: Extraoral roles in pathophysiology. Int J Biochem Cell Biol 2016; 77:197-204. [PMID: 27032752 DOI: 10.1016/j.biocel.2016.03.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 03/16/2016] [Accepted: 03/22/2016] [Indexed: 11/17/2022]
Abstract
Over the past decade tremendous progress has been made in understanding the functional role of bitter taste receptors (T2Rs) and bitter taste perception. This review will cover the recent advances made in identifying the role of T2Rs in pathophysiological states. T2Rs are widely expressed in various parts of human anatomy and have been shown to be involved in physiology of respiratory system, gastrointestinal tract and endocrine system. Empirical evidence has shown T2Rs to be an integral component of antimicrobial immune responses in upper respiratory tract infections. The studies on human airway smooth muscle cells have shown that a potent bitter tastant induced bronchodilatory effects mediated by bitter taste receptors. Clinical data suggests a role for T2R38 polymorphism in predisposition of individuals to chronic rhinosinusitis. The role of genetic variation in T2Rs and its impact on disease susceptibility have been investigated in various other disease risk factors such as alcohol dependence, head and neck cancers. Preliminary reports have demonstrated differential expression of functional T2Rs in breast cancer cell lines. Studies on the role of T2Rs in pathophysiology of diseases including chronic rhinosinusitis, asthma, cystic fibrosis, and cancer have been promising. However, research in this field is in its nascent stages, and more confirmatory studies on animal models and in clinical settings are required.
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Affiliation(s)
- Feroz Ahmed Shaik
- Manitoba Chemosensory Biology (MCSB) Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada; Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology (MCSB) Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada; Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
| | - Makoto Arakawa
- Manitoba Chemosensory Biology (MCSB) Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
| | - Kangmin Duan
- Manitoba Chemosensory Biology (MCSB) Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada; Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
| | - Rajinder P Bhullar
- Manitoba Chemosensory Biology (MCSB) Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology (MCSB) Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada; Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB R3E 0W2, Canada.
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Sakai H, Sato K, Kai Y, Chiba Y, Narita M. Denatonium and 6- n-Propyl-2-thiouracil, Agonists of Bitter Taste Receptor, Inhibit Contraction of Various Types of Smooth Muscles in the Rat and Mouse. Biol Pharm Bull 2016; 39:33-41. [DOI: 10.1248/bpb.b15-00426] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hiroyasu Sakai
- Department of Analytical Pathophysiology, Division of Pharmacy Professional Development and Research, Hoshi University
| | - Ken Sato
- Department of Analytical Pathophysiology, Division of Pharmacy Professional Development and Research, Hoshi University
| | - Yuki Kai
- Department of Analytical Pathophysiology, Division of Pharmacy Professional Development and Research, Hoshi University
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Abstract
PURPOSE OF REVIEW Although today's cornerstone therapies for asthma (inhaled bronchodilators and corticosteroids) target airway narrowing and lung inflammation, about half of treated asthmatic patients do not achieve good disease control. There is a clear need for new therapeutic approaches and novel drug targets. Recent research has unexpectedly revealed that certain taste receptors (particularly those involved in bitter taste transduction) are expressed in lung tissue. RECENT FINDINGS Bitter taste receptors are expressed in several cell types in the lungs (such as chemosensory cells, epithelial cells, smooth muscle cells, lymphocytes, and macrophages) and variously involved in ciliary beating, muscle relaxation, and/or inhibition of the production of inflammatory mediators. Here, we review recent research on the role of bitter taste receptors in experimental models of asthma and in asthmatics. SUMMARY The currently available data suggest that bitter taste receptor agonists have therapeutic potential in chronic obstructive airway diseases such as asthma.
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Devillier P, Naline E, Grassin-Delyle S. The pharmacology of bitter taste receptors and their role in human airways. Pharmacol Ther 2015; 155:11-21. [PMID: 26272040 DOI: 10.1016/j.pharmthera.2015.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The receptors involved in bitter taste perception (bitter taste receptors--T2Rs) constitute a family of G-protein-coupled receptors, of which around 29 subtypes have been identified in humans. T2R expression was initially thought to be confined to the oral cavity but has recently been described in a range of other tissues (such as the heart, gut, nasal cavity and lungs) and cell types (chemosensory, smooth muscle, endothelial, epithelial and inflammatory cells). Although it is still not clear whether endogenous T2R agonists exist, the T2R receptors recognize many natural and synthetic compounds, such as the acyl-homoserine lactones produced by bacteria, caffeine, chloroquine, and erythromycin. In the upper airways, T2Rs are involved in neurogenic inflammation and bacterial clearance. Their known effects in the lungs are exerted at three different levels. Firstly, T2R agonists increase the beating frequency of cilia on epithelial cells. Secondly, the T2Rs induce bronchial smooth muscle cells to relax. Thirdly, the T2R receptors expressed on immune cells (such as macrophages and mast cells) modulate production of pro-inflammatory mediators. Furthermore, T2R agonists are effective in inhibiting lung inflammation or smooth muscle contraction in ex vivo and asthma animal models, and are known to be involved in bacterial killing in the nasal cavity and enhancing lung function in humans. This review focuses on the pharmacology and physiological functions of T2R receptors in the upper and lower airways. It presents recently acquired knowledge suggesting that T2Rs may become valuable drug targets in the treatment of diseases such as asthma and chronic rhinosinusitis.
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Affiliation(s)
- Philippe Devillier
- Laboratoire de Pharmacologie, UPRES EA220, Hôpital Foch, 11 rue Guillaume Lenoir, 92150 Suresnes, France; Université Versailles Saint Quentin en Yvelines, UFR Sciences de la Santé, 2 avenue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Emmanuel Naline
- Laboratoire de Pharmacologie, UPRES EA220, Hôpital Foch, 11 rue Guillaume Lenoir, 92150 Suresnes, France; Université Versailles Saint Quentin en Yvelines, UFR Sciences de la Santé, 2 avenue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Stanislas Grassin-Delyle
- Laboratoire de Pharmacologie, UPRES EA220, Hôpital Foch, 11 rue Guillaume Lenoir, 92150 Suresnes, France; Université Versailles Saint Quentin en Yvelines, UFR Sciences de la Santé, 2 avenue de la source de la Bièvre, 78180 Montigny-le-Bretonneux, France.
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Upadhyaya JD, Singh N, Sikarwar AS, Chakraborty R, Pydi SP, Bhullar RP, Dakshinamurti S, Chelikani P. Dextromethorphan mediated bitter taste receptor activation in the pulmonary circuit causes vasoconstriction. PLoS One 2014; 9:e110373. [PMID: 25340739 PMCID: PMC4207743 DOI: 10.1371/journal.pone.0110373] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/11/2014] [Indexed: 12/14/2022] Open
Abstract
Activation of bitter taste receptors (T2Rs) in human airway smooth muscle cells leads to muscle relaxation and bronchodilation. This finding led to our hypothesis that T2Rs are expressed in human pulmonary artery smooth muscle cells and might be involved in regulating the vascular tone. RT-PCR was performed to reveal the expression of T2Rs in human pulmonary artery smooth muscle cells. Of the 25 T2Rs, 21 were expressed in these cells. Functional characterization was done by calcium imaging after stimulating the cells with different bitter agonists. Increased calcium responses were observed with most of the agonists, the largest increase seen for dextromethorphan. Previously in site-directed mutational studies, we have characterized the response of T2R1 to dextromethorphan, therefore, T2R1 was selected for further analysis in this study. Knockdown with T2R1 specific shRNA decreased mRNA levels, protein levels and dextromethorphan-induced calcium responses in pulmonary artery smooth muscle cells by up to 50%. To analyze if T2Rs are involved in regulating the pulmonary vascular tone, ex vivo studies using pulmonary arterial and airway rings were pursued. Myographic studies using porcine pulmonary arterial and airway rings showed that stimulation with dextromethorphan led to contraction of the pulmonary arterial and relaxation of the airway rings. This study shows that dextromethorphan, acting through T2R1, causes vasoconstrictor responses in the pulmonary circuit and relaxation in the airways.
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Affiliation(s)
| | - Nisha Singh
- Department of Oral Biology, University of Manitoba, Winnipeg, MB, Canada
| | - Anurag S. Sikarwar
- Departments of Pediatrics, Physiology, University of Manitoba, Winnipeg, MB, Canada
| | - Raja Chakraborty
- Department of Oral Biology, University of Manitoba, Winnipeg, MB, Canada
| | - Sai P. Pydi
- Department of Oral Biology, University of Manitoba, Winnipeg, MB, Canada
| | | | - Shyamala Dakshinamurti
- Departments of Pediatrics, Physiology, University of Manitoba, Winnipeg, MB, Canada
- Manitoba Institute of Child Health, Winnipeg, MB, Canada
| | - Prashen Chelikani
- Department of Oral Biology, University of Manitoba, Winnipeg, MB, Canada
- Manitoba Institute of Child Health, Winnipeg, MB, Canada
- * E-mail:
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