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Belloir C, Karolkowski A, Thomas A, Menin R, Briand L. Modulation of bitter taste receptors by yeast extracts. Food Res Int 2024; 190:114596. [PMID: 38945612 DOI: 10.1016/j.foodres.2024.114596] [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: 03/27/2024] [Revised: 05/21/2024] [Accepted: 06/01/2024] [Indexed: 07/02/2024]
Abstract
Yeast extracts (YEs) are used in foods because of their flavour properties and ability to reduce bitterness. The adenosine 5'-monophosphate (AMP) found in YEs is known to decrease the bitterness of some compounds. This study aimed to investigate the ability of YEs to inhibit bitter taste receptors (TAS2Rs) using in vitro cell-based assays. A screen of TAS2Rs activated by AMP and YEs revealed that AMP and the AMP-rich YE activated more TAS2Rs. The inhibitory effect of the AMP-rich YE on seven TAS2Rs activated by bitter agonists was studied. YE reduced TAS2R activation, increased the EC50 value and decreased the maximum amplitude, demonstrating competitive and non-competitive inhibitions. Amongst the nineteen TAS2Rs tested, seven showed 40 % or greater inhibition after treatment of AMP-rich YE. Our data provide a better understanding of the TAS2R inhibition mechanism of AMP-rich YEs and promote their use as a strategy to reduce bitterness in foods and medicines.
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Affiliation(s)
- Christine Belloir
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, F-21000 Dijon, France.
| | - Adeline Karolkowski
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, F-21000 Dijon, France.
| | | | - Rudy Menin
- Biospringer by Lesaffre, 94700 Maisons-Alfort, France.
| | - Loïc Briand
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, F-21000 Dijon, France.
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2
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Gu YP, Wang JM, Tian S, Gu PP, Duan JY, Gou LS, Liu YW. Activation of TAS2R4 signaling attenuates podocyte injury induced by high glucose. Biochem Pharmacol 2024; 226:116392. [PMID: 38942091 DOI: 10.1016/j.bcp.2024.116392] [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: 01/29/2024] [Revised: 05/27/2024] [Accepted: 06/25/2024] [Indexed: 06/30/2024]
Abstract
Bitter taste receptors (TAS2Rs) Tas2r108 gene possesses a high abundance in mouse kidney; however, the biological functions of Tas2r108 encoded receptor TAS2Rs member 4 (TAS2R4) are still unknown. In the present study, we found that mouse TAS2R4 (mTAS2R4) signaling was inactivated in chronic high glucose-stimulated mouse podocyte cell line MPC, evidenced by the decreased protein expressions of mTAS2R4 and phospholipase C β2 (PLCβ2), a key downstream molecule of mTAS2R4 signaling. Nonetheless, agonism of mTAS2R4 by quinine recovered mTAS2R4 and PLCβ2 levels, and increased podocyte cell viability as well as protein expressions of ZO-1 and nephrin, biomarkers of podocyte slit diaphragm, in high glucose-cultured MPC cells. However, blockage of mTAS2R4 signaling with mTAS2R4 blockers γ-aminobutyric acid and abscisic acid, a Gβγ inhibitor Gallein, or a PLCβ2 inhibitor U73122 all abolished the effects of quinine on NLRP3 inflammasome and p-NF-κB p65 as well as the functional podocyte proteins in MPC cells in a high glucose condition. Furthermore, knockdown of mTAS2R4 with lentivirus-carrying Tas2r108 shRNA also ablated the effect of quinine on the key molecules of the above inflammatory signalings and podocyte functions in high glucose-cultured MPC cells. In summary, we demonstrated that activation of TAS2R4 signaling alleviated the podocyte injury caused by chronic high glucose, and inhibition of NF-κB p65 and NLRP3 inflammasome mediated the protective effects of TAS2R4 activation on podocytes. Moreover, activation of TAS2R4 signaling could be an important strategy for prevention and treatment of diabetic kidney disease.
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Affiliation(s)
- Yan-Ping Gu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Jiang-Meng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Sai Tian
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Pan-Pan Gu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Jing-Yu Duan
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
| | - Ling-Shan Gou
- Center for Genetic Medicine, Xuzhou Maternity and Child Health Care Hospital, Xuzhou 221009, Jiangsu, China
| | - Yao-Wu Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China; Department of Pharmacology, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China.
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3
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Zuluaga G. Potential of Bitter Medicinal Plants: A Review of Flavor Physiology. Pharmaceuticals (Basel) 2024; 17:722. [PMID: 38931389 PMCID: PMC11206615 DOI: 10.3390/ph17060722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
The function of the sense of taste is usually confined to the ability to perceive the flavor of food to assess and use the nutrients necessary for healthy survival and to discard those that may be harmful, toxic, or unpleasant. It is almost unanimously agreed that the perception of bitter taste prevents the consumption of toxins from plants, decaying foods, and drugs. Forty years ago, while practicing medicine in a rural area of the Colombian Amazon, I had an unexpected encounter with the Inga Indians. I faced the challenge of accepting that their traditional medicine was effective and that the medicinal plants they used had a real therapeutic effect. Wanting to follow a process of learning about medicinal plants on their terms, I found that, for them, the taste of plants is a primary and fundamental key to understanding their functioning. One of the most exciting results was discovering the therapeutic value of bitter plants. The present review aims to understand whether there is any scientific support for this hypothesis from the traditional world. Can the taste of plants explain their possible therapeutic benefit? In the last 20 years, we have made novel advances in the knowledge of the physiology of taste. Our purpose will be to explore these scientific advances to determine if the bitter taste of medicinal plants benefits human health.
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Affiliation(s)
- Germán Zuluaga
- Grupo de Estudios en Sistemas Tradicionales de Salud, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá 111711, Colombia; ; Tel.: +57-311-2179102
- Centro de Estudios Médicos Interculturales, Cota 250010, Colombia
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4
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Nguyen H, Lin C, Sasimovich I, Bell K, Huang A, Leszkowicz E, Rawson NE, Reed DR. Thiazolidinediones are Partially Effective Bitter Blockers. Clin Ther 2024; 46:345-353. [PMID: 38462427 PMCID: PMC11116052 DOI: 10.1016/j.clinthera.2024.02.002] [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: 08/03/2023] [Revised: 12/14/2023] [Accepted: 02/11/2024] [Indexed: 03/12/2024]
Abstract
PURPOSE The bad bitter taste of some medicines is a barrier to overcoming noncompliance with medication use, especially life-saving drugs given to children and the elderly. Here, we evaluated a new class of bitter blockers (thiazolidinediones, TZDs). METHODS In this study, 2 TZDs were tested, rosiglitazone (ROSI) and a simpler form of TZD, using a high-potency sweetener as a positive control (neohesperidin dihydrochalcone, NHDC). We tested bitter-blocking effects using the bitter drugs tenofovir alafenamide fumarate (TAF), a treatment for HIV and hepatitis B infection, and praziquantel (PRAZ), a treatment for schistosomiasis, by conducting taste testing with 2 separate taste panels: a general panel (N = 97, 20-23 years, 82.5% female, all Eastern European) and a genetically informative panel (N = 158, including 68 twin pairs, 18-82 years, 76% female, 87% European ancestry). Participants rated the bitterness intensity of the solutions on a 100-point generalized visual analog scale. FINDINGS Person-to-person differences in drug bitterness were striking; TAF and PRAZ were weakly or not bitter for some people but moderately to highly bitter for others. Participants in both taste panels rated the bitter drugs TAF and PRAZ as less bitter on average when mixed with NHDC than when sampled alone. ROSI partially suppressed the bitterness of TAF and PRAZ, but effectiveness differed between the 2 panels: bitterness was significantly reduced for PRAZ but not TAF in the general panel and for TAF but not PRAZ in the genetically informative panel. ROSI was a more effective blocker than the other TZD. IMPLICATIONS These results suggest that TZDs are partially effective bitter blockers and the suppression efficacy differs from drug to drug, from person to person, and from panel to panel, suggesting other TZDs should be designed and tested with more drugs and on diverse populations to define which ones work best with which drugs and for whom. The discovery of bitter receptor blockers can improve compliance with medication use.
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Affiliation(s)
- Ha Nguyen
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
| | - Cailu Lin
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
| | | | - Katherine Bell
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
| | - Amy Huang
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
| | - Emilia Leszkowicz
- Department of Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Nancy E Rawson
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
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Singh N, Ulmer B, Medapati MR, Zhang C, Schroth RJ, Ghavami S, Chelikani P. Bitter Taste Receptor T2R14 and Autophagy Flux in Gingival Epithelial Cells. Cells 2024; 13:531. [PMID: 38534375 DOI: 10.3390/cells13060531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 03/28/2024] Open
Abstract
Macroautophagy (hereafter autophagy) is a lysosomal degradation pathway that functions in nutrient recycling and as a mechanism of innate immunity. Previously, we reported a novel host-bacteria interaction between cariogenic S. mutans and bitter taste receptor (T2R14) in gingival epithelial cells (GECs), leading to an innate immune response. Further, S. mutans might be using the host immune system to inhibit other Gram-positive bacteria, such as S. aureus. To determine whether these bacteria exploit the autophagic machinery of GEC, it is first necessary to evaluate the role of T2R14 in modulating autophagic flux. So far, the role of T2R14 in the regulation of autophagy is not well characterized. Therefore, in this study, for the first time, we report that T2R14 downregulates autophagy flux in GECs, and T2R14 knockout increases acidic vacuoles. However, the treatments of GEC WT with a T2R14 agonist and antagonist did not lead to a significant change in acidic vacuole formation. Transmission electron microscopy morphometric results also suggested an increased number of autophagic vesicles in T2R14-knockout GEC. Further, our results suggest that S. mutans competence stimulating peptide CSP-1 showed robust intracellular calcium release and this effect is both T2R14- and autophagy protein 7-dependent. In this study, we provide the first evidence that T2R14 modulates autophagy flux in GEC. The results of the current study could help in identifying the impact of T2R in regulation of the immuno-microenvironment of GEC and subsequently oral health.
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Affiliation(s)
- Nisha Singh
- Manitoba Chemosensory Biology (MCSB) Research Group, Department of Oral Biology, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB R3E 0W4, Canada
- Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ben Ulmer
- Manitoba Chemosensory Biology (MCSB) Research Group, Department of Oral Biology, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB R3E 0W4, Canada
- Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Manoj Reddy Medapati
- Manitoba Chemosensory Biology (MCSB) Research Group, Department of Oral Biology, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB R3E 0W4, Canada
- Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Christine Zhang
- University of Manitoba Flow Cytometry Core Facility, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Robert J Schroth
- Manitoba Chemosensory Biology (MCSB) Research Group, Department of Oral Biology, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB R3E 0W4, Canada
- Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Saeid Ghavami
- Research Institute of Oncology and Hematology, Cancer Care Manitoba, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Department of Human Anatomy and Cell Science, University of Manitoba College of Medicine, Winnipeg, MB R3E 0W2, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology (MCSB) Research Group, Department of Oral Biology, University of Manitoba, 780 Bannatyne Avenue, Winnipeg, MB R3E 0W4, Canada
- Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Human Anatomy and Cell Science, University of Manitoba College of Medicine, Winnipeg, MB R3E 0W2, Canada
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An JP, Wang Y, Munger SD, Tang X. A review on natural sweeteners, sweet taste modulators and bitter masking compounds: structure-activity strategies for the discovery of novel taste molecules. Crit Rev Food Sci Nutr 2024:1-24. [PMID: 38494695 DOI: 10.1080/10408398.2024.2326012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Growing demand for the tasty and healthy food has driven the development of low-calorie sweeteners, sweet taste modulators, and bitter masking compounds originated from natural sources. With the discovery of human taste receptors, increasing numbers of sweet taste modulators have been identified through human taste response and molecular docking techniques. However, the discovery of novel taste-active molecules in nature can be accelerated by using advanced spectrometry technologies based on structure-activity relationships (SARs). SARs explain why structurally similar compounds can elicit similar taste qualities. Given the characterization of structural information from reported data, strategies employing SAR techniques to find structurally similar compounds become an innovative approach to expand knowledge of sweeteners. This review aims to summarize the structural patterns of known natural non-nutritive sweeteners, sweet taste enhancers, and bitter masking compounds. Innovative SAR-based approaches to explore sweetener derivatives are also discussed. Most sweet-tasting flavonoids belong to either the flavanonols or the dihydrochalcones and known bitter masking molecules are flavanones. Based on SAR findings that structural similarities are related to the sensory properties, innovative methodologies described in this paper can be applied to screen and discover the derivatives of taste-active compounds or potential taste modulators.
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Affiliation(s)
- Jin-Pyo An
- Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
| | - Yu Wang
- Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
| | - Steven D Munger
- Center for Smell and Taste, Department of Pharmacology and Therapeutics, Department of Otolaryngology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Xixuan Tang
- Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
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Soh R, Fu L, Guo WM, Seetoh WG, Koay A. Inhibitors of human bitter taste receptors from the five-flavour berry, Schisandra chinensis. Food Funct 2023; 14:10700-10708. [PMID: 37986606 DOI: 10.1039/d3fo02303f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The human bitter taste 2 receptor member 16 (TAS2R16) is one of 25 class A G-protein-coupled receptors (GPCRs) and responds to a variety of molecules responsible for the bitter taste sensation perceived in humans. TAS2R16 can be activated by β-glucopyranosides, and its activation can be inhibited by probenecid, a synthetic drug compound used to treat gout. In this study we describe naturally derived compounds which can inhibit the activation of TAS2R16 by salicin in vitro. These compounds belong to the lignan class derived from the fruit of Schisandra chinensis, which is commonly known as the five-flavour berry. We further tested other analogs with this lignan scaffold, found their differential inhibitory activities towards TAS2R16 in vitro, and sought to rationalize the activity using molecular docking of these lignans on a computationally modelled structure of TAS2R16. Selected lignans with inhibitory activity against other TAS2Rs reveal sub-millimolar inhibitory activity towards TAS2R10, TAS2R14, and TAS2R43 in cell-based assays. These compounds with demonstrated in vitro inhibition of bitter taste receptors may serve as tool compounds to investigate the molecular mechanisms of hTAS2Rs biology in gustatory and non-gustatory tissues.
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Affiliation(s)
- Ryan Soh
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Lin Fu
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Wei Mei Guo
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Wei-Guang Seetoh
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
| | - Ann Koay
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #02-01 Nanos, Singapore 138669, Singapore.
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Zhou Y, Zhang Y, Hong H, Luo Y, Li B, Tan Y. Mastering the art of taming: Reducing bitterness in fish by-products derived peptides. Food Res Int 2023; 173:113241. [PMID: 37803554 DOI: 10.1016/j.foodres.2023.113241] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 10/08/2023]
Abstract
Processed fish by-products are valuable sources of peptides due to their high protein content. However, the bitterness of these peptides can limit their use. This review outlines the most recent advancements and information regarding the reduction of bitterness in fish by-products derived peptides. The sources and factors influencing bitterness, the transduction mechanisms involved, and strategies for reducing bitterness are highlighted. Bitterness in peptides is mainly influenced by the source, preparation method, presence of hydrophobic amino acid groups, binding to bitter receptors, and amino acid sequence. The most widely utilized techniques for eliminating bitterness or enhancing taste include the Maillard reaction, encapsulation, seperating undesirable components, and bitter-blockers. Finally, a summary of the current challenges and future prospects in the domain of fish by-products derived peptides is given. Despite some limitations, such as residual bitterness and limited industrial application, there is a need for further research to reduce the bitterness of fish by-products derived peptides. To achieve this goal, future studies should focus on the technology of fish by-products derived peptide bitterness diminishment, with the aim of producing high-quality products that meet consumer expectations.
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Affiliation(s)
- Yongjie Zhou
- Laboratory of Precision Nutrition and Food Quality, Ministry of Education, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Yan Zhang
- Experimental Seafood Processing Laboratory, Coastal Research and Extension Center, Mississippi State University, Pascagoula, MS 39567, USA
| | - Hui Hong
- Laboratory of Precision Nutrition and Food Quality, Ministry of Education, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Yongkang Luo
- Laboratory of Precision Nutrition and Food Quality, Ministry of Education, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Bo Li
- Laboratory of Precision Nutrition and Food Quality, Ministry of Education, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Yuqing Tan
- Laboratory of Precision Nutrition and Food Quality, Ministry of Education, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
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Nguyen H, Lin C, Sasimovich I, Bell K, Huang A, Leszkowicz E, Rawson NE, Reed DR. Thiazolidinediones are partially effective bitter blockers. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552460. [PMID: 37609224 PMCID: PMC10441302 DOI: 10.1101/2023.08.08.552460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Purpose The bad bitter taste of some medicines is a barrier to overcoming non-compliance with medication use, especially life-saving drugs given to children and the elderly. Here we evaluated a new class of bitter blockers (thiazolidinediones; TZDs). Methods In this study, two TZDs were tested, rosiglitazone (ROSI) and a simpler form of TZD, using a high-potency sweetener as a positive control (neohesperidin dihydrochalcone, NHDC). We tested bitter-blocking effects using the bitter drugs tenofovir alafenamide fumarate (TAF), a treatment for HIV and hepatitis B infection, and praziquantel (PRAZ), a treatment for schistosomiasis, by conducting taste testing with two separate taste panels: a general panel (N=97, 20-23 yrs, 82.5% female, all Eastern European) and a genetically informative panel (N=158, including 68 twin pairs, 18-82 yrs, 76% female, 87% European ancestry). Participants rated the bitterness intensity of the solutions on a 100-point generalized visual analog scale. Findings Participants in both taste panels rated the bitter drugs TAF and PRAZ as less bitter on average when mixed with NHDC than when sampled alone. ROSI partially suppressed the bitterness of TAF and PRAZ, but effectiveness differed between the two panels: bitterness was significantly reduced for PRAZ but not TAF in the general panel and for TAF but not PRAZ in the genetically informative panel. ROSI was a more effective blocker than the other TZD. Implications These results suggest that TZDs are partially effective bitter blockers, suggesting other TZDs should be designed and tested with more drugs and on diverse populations to define which ones work best with which drugs and for whom. The discovery of bitter receptor blockers can improve compliance with medication use.
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Affiliation(s)
- Ha Nguyen
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Cailu Lin
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | | | - Katherine Bell
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Amy Huang
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Emilia Leszkowicz
- Dept. Animal and Human Physiology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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Kouakou YI, Lee RJ. Interkingdom Detection of Bacterial Quorum-Sensing Molecules by Mammalian Taste Receptors. Microorganisms 2023; 11:1295. [PMID: 37317269 DOI: 10.3390/microorganisms11051295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/11/2023] [Accepted: 05/13/2023] [Indexed: 06/16/2023] Open
Abstract
Bitter and sweet taste G protein-coupled receptors (known as T2Rs and T1Rs, respectively) were originally identified in type II taste cells on the tongue, where they signal perception of bitter and sweet tastes, respectively. Over the past ~15 years, taste receptors have been identified in cells all over the body, demonstrating a more general chemosensory role beyond taste. Bitter and sweet taste receptors regulate gut epithelial function, pancreatic β cell secretion, thyroid hormone secretion, adipocyte function, and many other processes. Emerging data from a variety of tissues suggest that taste receptors are also used by mammalian cells to "eavesdrop" on bacterial communications. These receptors are activated by several quorum-sensing molecules, including acyl-homoserine lactones and quinolones from Gram-negative bacteria such as Pseudomonas aeruginosa, competence stimulating peptides from Streptococcus mutans, and D-amino acids from Staphylococcus aureus. Taste receptors are an arm of immune surveillance similar to Toll-like receptors and other pattern recognition receptors. Because they are activated by quorum-sensing molecules, taste receptors report information about microbial population density based on the chemical composition of the extracellular environment. This review summarizes current knowledge of bacterial activation of taste receptors and identifies important questions remaining in this field.
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Affiliation(s)
- Yobouet Ines Kouakou
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert J Lee
- Department of Otorhinolaryngology and Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Chen S, Zhou X, Lu Y, Xu K, Wen J, Cui M. Anti-HIV drugs lopinavir/ritonavir activate bitter taste receptors. Chem Senses 2023; 48:bjad035. [PMID: 37625013 PMCID: PMC10486187 DOI: 10.1093/chemse/bjad035] [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: 05/02/2023] [Indexed: 08/27/2023] Open
Abstract
Lopinavir and ritonavir (LPV/r) are the primary anti-human immunodeficiency virus (HIV) drugs recommended by the World Health Organization for treating children aged 3 years and above who are infected with the HIV. These drugs are typically available in liquid formulations to aid in dosing for children who cannot swallow tablets. However, the strong bitter taste associated with these medications can be a significant obstacle to adherence, particularly in young children, and can jeopardize the effectiveness of the treatment. Studies have shown that poor palatability can affect the survival rate of HIV-infected children. Therefore, developing more child-friendly protease inhibitor formulations, particularly those with improved taste, is critical for children with HIV. The molecular mechanism by which lopinavir and ritonavir activate bitter taste receptors, TAS2Rs, is not yet clear. In this study, we utilized a calcium mobilization assay to characterize the activation of bitter taste receptors by lopinavir and ritonavir. We discovered that lopinavir activates TAS2R1 and TAS2R13, while ritonavir activates TAS2R1, TAS2R8, TAS2R13, and TAS2R14. The development of bitter taste blockers that target these receptors with a safe profile would be highly desirable in eliminating the unpleasant bitter taste of these anti-HIV drugs.
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Affiliation(s)
- Shurui Chen
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Xinyi Zhou
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Yongcheng Lu
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Keman Xu
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Jiao Wen
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Meng Cui
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, United States
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, United States
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12
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Yu J, Xie J, Xie H, Hu Q, Wu Z, Cai X, Guo Z, Lin J, Han L, Zhang D. Strategies for Taste Masking of Orodispersible Dosage Forms: Time, Concentration, and Perception. Mol Pharm 2022; 19:3007-3025. [PMID: 35848076 DOI: 10.1021/acs.molpharmaceut.2c00199] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Orodispersible dosage forms, characterized as quick dissolving and swallowing without water, have recently gained great attention from the pharmaceutical industry, as these forms can satisfy the needs of children, the elderly, and patients suffering from mental illnesses. However, poor taste by thorough exposure of the drugs' dissolution in the oral cavity hinders the effectiveness of the orodispersible dosage forms. To bridge this gap, we put forward three taste-masking strategies with respect to the intensity of time, concentration, and perception. We further investigated the raw material processing, the composition of auxiliary material, formulation techniques, and process control in each strategy and drew conclusions about their effects on taste masking.
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Affiliation(s)
- Ji Yu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Jin Xie
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Huijuan Xie
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Qi Hu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Zhenfeng Wu
- Key Laboratory of Modern Preparation of Chinese Medicine, Ministry of Education, Jiangxi University of Chinese Medicine, Nanchang 330004, PR China
| | - Xinfu Cai
- Sichuan Guangda Pharmaceutical Co., Ltd., Pengzhou 611930, PR China
| | - Zhiping Guo
- Sichuan Houde Pharmaceutical Technology Co., Ltd., Chengdu 610041, PR China
| | - Junzhi Lin
- TCM Regulating Metabolic Diseases Key Laboratory of Sichuan Province, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610072, PR China
| | - Li Han
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
| | - Dingkun Zhang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Pharmacy School, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, PR China
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13
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Margulis E, Slavutsky Y, Lang T, Behrens M, Benjamini Y, Niv MY. BitterMatch: recommendation systems for matching molecules with bitter taste receptors. J Cheminform 2022; 14:45. [PMID: 35799226 PMCID: PMC9261901 DOI: 10.1186/s13321-022-00612-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/14/2022] [Indexed: 11/10/2022] Open
Abstract
Bitterness is an aversive cue elicited by thousands of chemically diverse compounds. Bitter taste may prevent consumption of foods and jeopardize drug compliance. The G protein-coupled receptors for bitter taste, TAS2Rs, have species-dependent number of subtypes and varying expression levels in extraoral tissues. Molecular recognition by TAS2R subtypes is physiologically important, and presents a challenging case study for ligand-receptor matchmaking. Inspired by hybrid recommendation systems, we developed a new set of similarity features, and created the BitterMatch algorithm that predicts associations of ligands to receptors with ~ 80% precision at ~ 50% recall. Associations for several compounds were tested in-vitro, resulting in 80% precision and 42% recall. The encouraging performance was achieved by including receptor properties and integrating experimentally determined ligand-receptor associations with chemical ligand-to-ligand similarities. BitterMatch can predict off-targets for bitter drugs, identify novel ligands and guide flavor design. The novel features capture information regarding the molecules and their receptors, which could inform various chemoinformatic tasks. Inclusion of neighbor-informed similarities improves as experimental data mounts, and provides a generalizable framework for molecule-biotarget matching.
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Affiliation(s)
- Eitan Margulis
- The Institute of Biochemistry, Food Science and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuli Slavutsky
- Department of Statistics and Data Science, Faculty of Social Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tatjana Lang
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Maik Behrens
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Yuval Benjamini
- Department of Statistics and Data Science, Faculty of Social Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Masha Y Niv
- The Institute of Biochemistry, Food Science and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
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14
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Bhatia V, de Jesus VC, Shaik FA, Jaggupilli A, Singh N, Chelikani P, Atukorallaya D. Extraoral expression and characterization of bitter taste receptors in
Astyanax mexicanus
(Mexican Tetra Fish). FASEB Bioadv 2022; 4:574-584. [PMID: 36089978 PMCID: PMC9447421 DOI: 10.1096/fba.2022-00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Vikram Bhatia
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
| | - Vivianne Cruz de Jesus
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
| | - Feroz Ahmed Shaik
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
| | - Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
| | - Devi Atukorallaya
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
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15
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Yu Z, Wang Y, Zhao W, Li J, Shuian D, Liu J. Identification of Oncorhynchus mykiss nebulin-derived peptides as bitter taste receptor TAS2R14 blockers by in silico screening and molecular docking. Food Chem 2022; 368:130839. [PMID: 34419799 DOI: 10.1016/j.foodchem.2021.130839] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 06/24/2021] [Accepted: 08/09/2021] [Indexed: 01/03/2023]
Abstract
Human bitter taste receptor TAS2R14 (T2R14) can widely perceive bitterness, which has always been an issue for people to overcome. This study was aimed at identifying bioactive peptides obtained from Oncorhynchus mykiss nebulin hydrolysates as bitter taste receptor blockers by physicochemical property prediction, molecular docking, and in vitro determination of bitterness intensity using electronic tongue. Exploration of the interaction mechanism of these peptides with T2R14 by molecular docking models indicated that peptides ADM and ADW had high affinities for T2R14 to block the binding of bitter substances into the receptor. Addition of ADM and ADW to quinine caused reduction in bitterness intensity, with IC50 values of 420.32 ± 6.26 μM and 403.29 ± 4.10 μM, respectively. Hydrogen bond interaction and hydrophobic interaction were responsible for manifesting the high affinities of these peptides for the receptor. Residues Thr86, Asp168, and Phe247 may be the key amino acids within the binding site.
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Affiliation(s)
- Zhipeng Yu
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China
| | - Yingxue Wang
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China
| | - Wenzhu Zhao
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China.
| | - Jianrong Li
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, PR China
| | - David Shuian
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, PR China
| | - Jingbo Liu
- Lab of Nutrition and Functional Food, Jilin University, Changchun 130062, PR China
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16
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Topin J, Bouysset C, Pacalon J, Kim Y, Rhyu MR, Fiorucci S, Golebiowski J. Functional molecular switches of mammalian G protein-coupled bitter-taste receptors. Cell Mol Life Sci 2021; 78:7605-7615. [PMID: 34687318 PMCID: PMC11073308 DOI: 10.1007/s00018-021-03968-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/20/2021] [Accepted: 09/26/2021] [Indexed: 10/20/2022]
Abstract
Bitter taste receptors (TAS2Rs) are a poorly understood subgroup of G protein-coupled receptors (GPCRs). The experimental structure of these receptors has yet to be determined, and key-residues controlling their function remain mostly unknown. We designed an integrative approach to improve comparative modeling of TAS2Rs. Using current knowledge on class A GPCRs and existing experimental data in the literature as constraints, we pinpointed conserved motifs to entirely re-align the amino-acid sequences of TAS2Rs. We constructed accurate homology models of human TAS2Rs. As a test case, we examined the accuracy of the TAS2R16 model with site-directed mutagenesis and in vitro functional assays. This combination of in silico and in vitro results clarifies sequence-function relationships and proposes functional molecular switches that encode agonist sensing and downstream signaling mechanisms within mammalian TAS2Rs sequences.
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Affiliation(s)
- Jérémie Topin
- Institut de Chimie de Nice UMR7272, Université Côte d'Azur, CNRS, Nice, France.
| | - Cédric Bouysset
- Institut de Chimie de Nice UMR7272, Université Côte d'Azur, CNRS, Nice, France
| | - Jody Pacalon
- Institut de Chimie de Nice UMR7272, Université Côte d'Azur, CNRS, Nice, France
| | - Yiseul Kim
- Korea Food Research Institute, 245 Iseo-myeon, Wanju-gun, Jeollabuk-do, 55365, Republic of Korea
| | - Mee-Ra Rhyu
- Korea Food Research Institute, 245 Iseo-myeon, Wanju-gun, Jeollabuk-do, 55365, Republic of Korea
| | - Sébastien Fiorucci
- Institut de Chimie de Nice UMR7272, Université Côte d'Azur, CNRS, Nice, France.
| | - Jérôme Golebiowski
- Institut de Chimie de Nice UMR7272, Université Côte d'Azur, CNRS, Nice, France
- Department of Brain and Cognitive Sciences, DGIST, 333, Techno JungAng, Daero, HyeongPoong Myeon, Daegu, 711-873, Republic of Korea
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17
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Zhao W, Li D, Wang Y, Kan R, Ji H, Su L, Yu Z, Li J. Identification and molecular docking of peptides from Mizuhopecten yessoensis myosin as human bitter taste receptor T2R14 blockers. Food Funct 2021; 12:11966-11973. [PMID: 34747964 DOI: 10.1039/d1fo02447g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bitter taste receptor 14(T2R14) is one of the most widely regulated bitter taste receptors (T2Rs) and plays a vital role in the research of T2R blockers. In this study, potential T2R14 blockers were identified from the myosin of Mizuhopecten yessoensis. Myosin was hydrolyzed in silico by gastrointestinal proteases, and the peptides were obtained. The peptides' biological activity, solubility, and toxicity were predicted, and the potential T2R14 blocking peptides were docked with T2R14. Subsequently, the in vitro T2R14 blocking activity of the selected peptide was verified by an electronic tongue. The results showed that QRPR had T2R14 blocking activity with an IC50 value of 256.69 ± 1.91 μM. Molecular docking analysis suggested the key role of the amino residues Asp168, Leu178, Asn157, and Ile262 in blocking T2R14, and revealed that the amino acid residues of T2R14 bound with the peptide QRPR via electrostatic interaction, hydrophobic interaction, conventional hydrogen bond, and hydrogen bond. The novel T2R14 blocking peptide QRPR is a potential candidate for suppressing bitterness.
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Affiliation(s)
- Wenzhu Zhao
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Donghui Li
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Yingxue Wang
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Ruotong Kan
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Huizhuo Ji
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Lijun Su
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Zhipeng Yu
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
| | - Jianrong Li
- College of Food Science and Engineering, Bohai University, Jinzhou 121013, P.R. China.
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18
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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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19
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On the human taste perception: Molecular-level understanding empowered by computational methods. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.07.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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20
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Schwiebert E, Wang Y, Xi R, Choma K, Streiff J, Flammer LJ, Rivers N, Ozdener MH, Margolskee RF, Christensen CM, Rawson NE, Jiang P, Breslin PAS. Inhibition of Bitter Taste from Oral Tenofovir Alafenamide. Mol Pharmacol 2021; 99:319-327. [PMID: 33824185 DOI: 10.1124/molpharm.120.000071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 03/01/2021] [Indexed: 11/22/2022] Open
Abstract
Children have difficulty swallowing capsules. Yet, when presented with liquid formulations, children often reject oral medications due to their intense bitterness. Presently, effective strategies to identify methods, reagents, and tools to block bitterness remain elusive. For a specific bitter-tasting drug, identification of the responsible bitter receptors and discovery of antagonists for those receptors can provide a method to block perceived bitterness. We have identified a compound (6-methylflavone) that can block responses to an intensely bitter-tasting anti-human immunodeficiency virus (HIV) drug, tenofovir alafenamide (TAF), using a primary human taste bud epithelial cell culture as a screening platform. Specifically, TAS2R39 and TAS2R1 are the main type 2 taste receptors responding to TAF observed via heterologously expressing specific TAS2R receptors into HEK293 cells. In this assay, 6-methylflavone blocked the responses of TAS2R39 to TAF. In human sensory testing, 8 of 16 subjects showed reduction in perceived bitterness of TAF after pretreating (or "prerinsing") with 6-methylflavone and mixing 6-methylflavone with TAF. Bitterness was completely and reliably blocked in two of these subjects. These data demonstrate that a combined approach of human taste cell culture-based screening, receptor-specific assays, and human psychophysical testing can successfully discover molecules for blocking perceived bitterness of pharmaceuticals, such as the HIV therapeutic TAF. Our hope is to use bitter taste blockers to increase medical compliance with these vital medicines. SIGNIFICANCE STATEMENT: Identification of a small molecule that inhibits bitter taste from tenofovir alafenamide may increase the compliance in treating children with human immunodeficiency virus infections.
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Affiliation(s)
- Erik Schwiebert
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Yi Wang
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Ranhui Xi
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Katarzyna Choma
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - John Streiff
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Linda J Flammer
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Natasha Rivers
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Mehmet Hakan Ozdener
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Robert F Margolskee
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Carol M Christensen
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Nancy E Rawson
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Peihua Jiang
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
| | - Paul A S Breslin
- Discovery Biomed, Birmingham, Alabama (E.S., J.S.); Monell Chemical Senses Center, Philadelphia, Pennsylvania (Y.W., R.X., K.C., L.J.F., N.R., M.H.O., R.F.M., C.M.C., N.E.R., P.J., P.A.S.B.); and Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey (P.A.S.B.)
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21
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Welcome MO, Mastorakis NE. The taste of neuroinflammation: Molecular mechanisms linking taste sensing to neuroinflammatory responses. Pharmacol Res 2021; 167:105557. [PMID: 33737243 DOI: 10.1016/j.phrs.2021.105557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 03/10/2021] [Accepted: 03/10/2021] [Indexed: 02/07/2023]
Abstract
Evidence indicates a critical role of neuroinflammatory response as an underlying pathophysiological process in several central nervous system disorders, including neurodegenerative diseases. However, the molecular mechanisms that trigger neuroinflammatory processes are not fully known. The discovery of bitter taste receptors in regions other than the oral cavity substantially increased research interests on their functional roles in extra-oral tissues. It is now widely accepted that bitter taste receptors, for instance, in the respiratory, intestinal, reproductive and urinary tracts, are crucial not only for sensing poisonous substances, but also, act as immune sentinels, mobilizing defense mechanisms against pathogenic aggression. The relatively recent discovery of bitter taste receptors in the brain has intensified research investigation on the functional implication of cerebral bitter taste receptor expression. Very recent data suggest that responses of bitter taste receptors to neurotoxins and microbial molecules, under normal condition, are necessary to prevent neuroinflammatory reactions. Furthermore, emerging data have revealed that downregulation of key components of the taste receptor signaling cascade leads to increased oxidative stress and inflammasome signaling in neurons that ultimately culminate in neuroinflammation. Nevertheless, the mechanisms that link taste receptor mediated surveillance of the extracellular milieu to neuroinflammatory responses are not completely understood. This review integrates new data on the molecular mechanisms that link bitter taste receptor sensing to neuroinflammatory responses. The role of bitter taste receptor-mediated sensing of toxigenic substances in brain disorders is also discussed. The therapeutic significance of targeting these receptors for potential treatment of neurodegenerative diseases is also highlighted.
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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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22
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Abstract
G protein-coupled receptors (GPCRs) play a central role in regulating the functions of a diverse range of cell types in the airway. Taste 2 receptor (T2R) family of GPCRs is responsible for the transduction of bitter taste; however, recent studies have demonstrated that different subtypes of T2Rs and key components of T2R signaling are expressed in several extra-oral tissues including airways with many physiological roles. In the lung, expression of T2Rs has been confirmed in multiple airway cell types including airway smooth muscle (ASM) cells, various epithelial cell subtypes, and on both resident and migratory immune cells. Most importantly, activation of T2Rs with a variety of putative agonists elicits unique signaling in ASM and specialized airway epithelial cells resulting in the inhibition of ASM contraction and proliferation, promotion of ciliary motility, and innate immune response in chemosensory airway epithelial cells. Here we discuss the expression of T2Rs and the mechanistic basis of their function in the structural cells of the airways with some useful insights on immune cells in the context of allergic asthma and other upper airway inflammatory disorders. Emphasis on T2R biology and pharmacology in airway cells has an ulterior goal of exploiting T2Rs for therapeutic benefit in obstructive airway diseases.
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23
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Andrews D, Salunke S, Cram A, Bennett J, Ives RS, Basit AW, Tuleu C. Bitter-blockers as a taste masking strategy: A systematic review towards their utility in pharmaceuticals. Eur J Pharm Biopharm 2021; 158:35-51. [DOI: 10.1016/j.ejpb.2020.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 09/17/2020] [Accepted: 10/25/2020] [Indexed: 12/21/2022]
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24
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Medapati MR, Bhagirath AY, Singh N, Chelikani P. Pharmacology of T2R Mediated Host-Microbe Interactions. Handb Exp Pharmacol 2021; 275:177-202. [PMID: 33580389 DOI: 10.1007/164_2021_435] [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] [Indexed: 12/12/2022]
Abstract
Bitter taste receptors (T2Rs) belong to the G protein-coupled receptor superfamily. Humans express 25 T2Rs that are known to detect several bitter compounds including bacterial quorum sensing molecules (QSM). Primarily found to be key receptors for bitter sensation T2Rs are known to play an important role in mediating innate immune responses in oral and extraoral tissues. Several studies have led to identification of Gram-negative and Gram-positive bacterial QSMs as agonists for T2Rs in airway epithelial cells and immune cells. However, the pharmacological characterization for many of the QSM-T2R interactions remains poorly defined. In this chapter, we discuss the extraoral roles including localization of T2Rs in extracellular vesicles, molecular pharmacology of QSM-T2R interactions, role of T2Rs in mediating innate immune responses, and some of the challenges in understanding T2R pharmacology.
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Affiliation(s)
- Manoj Reddy Medapati
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Anjali Y Bhagirath
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, University of Manitoba, Winnipeg, MB, Canada.
- Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada.
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25
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Liang Q, Shu F, Dong X, Feng P. The evolution of a bitter taste receptor gene in primates. Chem Senses 2021; 46:6449468. [PMID: 34864939 DOI: 10.1093/chemse/bjab049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bitter taste perception is critical to prevent animals from ingesting potentially harmful substances. The aim of this study was to characterize the evolution of T2R4 and test the hypothesis that different regions of the T2R gene are subject to disparate selective pressures, with extracellular regions (ECs) being erratic while transmembrane (TMs) and intracellular regions (ICs) being constrained. Thus, we examined the selective pressures acting on T2R4 and its different regions in 37 primates, and discovered that T2R4 and ECs were subject to neutral evolution and purifying selection, respectively, whereas both TMs and ICs showed purifying selection, as suggested by the hypothesis. We attribute this result to the relatively conservative property of T2R4 gene and the limited number of bitter tastants that T2R4 can respond to. Furthermore, we found that positive selection had acted on the first loop of extracellular regions (EL1). In contrast, the second loop (EL2) and transmembrane region-3, -6, -7 (TM367) were subject to purifying selection, and the third loop (EL3) was subject to neutral evolution. This discovery is probably because EL2, EL3, and TMs play a crucial role in the ligand-binding process, and EL1 is involved in the tastant recognition process. We further tested whether the ω of T2R4 differs among species with different diets and found that a specialized diet affected the evolution of T2R4. Feeding habits, fewer T2Rs, and a dietary shift may account for the results. This study can help to uncover the evolution of T2Rs during the primate evolutionary course.
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Affiliation(s)
- Qiufang Liang
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, Guangxi, China.,Guangxi Key Laboratory of Rare and Endangered Animal Ecology, Guangxi Normal University, Guilin, Guangxi, China
| | - Fanglan Shu
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, Guangxi, China.,Guangxi Key Laboratory of Rare and Endangered Animal Ecology, Guangxi Normal University, Guilin, Guangxi, China
| | - Xiaoyan Dong
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, Guangxi, China.,Guangxi Key Laboratory of Rare and Endangered Animal Ecology, Guangxi Normal University, Guilin, Guangxi, China
| | - Ping Feng
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, Guangxi, China.,Guangxi Key Laboratory of Rare and Endangered Animal Ecology, Guangxi Normal University, Guilin, Guangxi, China
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26
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Ahmad R, Dalziel JE. G Protein-Coupled Receptors in Taste Physiology and Pharmacology. Front Pharmacol 2020; 11:587664. [PMID: 33390961 PMCID: PMC7774309 DOI: 10.3389/fphar.2020.587664] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
Abstract
Heterotrimeric G protein-coupled receptors (GPCRs) comprise the largest receptor family in mammals and are responsible for the regulation of most physiological functions. Besides mediating the sensory modalities of olfaction and vision, GPCRs also transduce signals for three basic taste qualities of sweet, umami (savory taste), and bitter, as well as the flavor sensation kokumi. Taste GPCRs reside in specialised taste receptor cells (TRCs) within taste buds. Type I taste GPCRs (TAS1R) form heterodimeric complexes that function as sweet (TAS1R2/TAS1R3) or umami (TAS1R1/TAS1R3) taste receptors, whereas Type II are monomeric bitter taste receptors or kokumi/calcium-sensing receptors. Sweet, umami and kokumi receptors share structural similarities in containing multiple agonist binding sites with pronounced selectivity while most bitter receptors contain a single binding site that is broadly tuned to a diverse array of bitter ligands in a non-selective manner. Tastant binding to the receptor activates downstream secondary messenger pathways leading to depolarization and increased intracellular calcium in TRCs, that in turn innervate the gustatory cortex in the brain. Despite recent advances in our understanding of the relationship between agonist binding and the conformational changes required for receptor activation, several major challenges and questions remain in taste GPCR biology that are discussed in the present review. In recent years, intensive integrative approaches combining heterologous expression, mutagenesis and homology modeling have together provided insight regarding agonist binding site locations and molecular mechanisms of orthosteric and allosteric modulation. In addition, studies based on transgenic mice, utilizing either global or conditional knock out strategies have provided insights to taste receptor signal transduction mechanisms and their roles in physiology. However, the need for more functional studies in a physiological context is apparent and would be enhanced by a crystallized structure of taste receptors for a more complete picture of their pharmacological mechanisms.
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Affiliation(s)
- Raise Ahmad
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
| | - Julie E Dalziel
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch, Palmerston North, New Zealand
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27
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A formulation for suppressing bitter taste in the human oral cavity. Physiol Behav 2020; 226:113129. [DOI: 10.1016/j.physbeh.2020.113129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 12/11/2022]
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28
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Di Pizio A, Nicoli A. In Silico Molecular Study of Tryptophan Bitterness. Molecules 2020; 25:molecules25204623. [PMID: 33050648 PMCID: PMC7587216 DOI: 10.3390/molecules25204623] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022] Open
Abstract
Tryptophan is an essential amino acid, required for the production of serotonin. It is the most bitter amino acid and its bitterness was found to be mediated by the bitter taste receptor TAS2R4. Di-tryptophan has a different selectivity profile and was found to activate three bitter taste receptors, whereas tri-tryptophan activated five TAS2Rs. In this work, the selectivity/promiscuity profiles of the mono-to-tri-tryptophans were explored using molecular modeling simulations to provide new insights into the molecular recognition of the bitter tryptophan. Tryptophan epitopes were found in all five peptide-sensitive TAS2Rs and the best tryptophan epitope was identified and characterized at the core of the orthosteric binding site of TAS2R4.
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29
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Masamoto M, Mitoh Y, Kobashi M, Shigemura N, Yoshida R. Effects of bitter receptor antagonists on behavioral lick responses of mice. Neurosci Lett 2020; 730:135041. [PMID: 32413538 DOI: 10.1016/j.neulet.2020.135041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 10/24/2022]
Abstract
Bitter taste receptors TAS2Rs detect noxious compounds in the oral cavity. Recent heterologous expression studies reported that some compounds function as antagonists for human TAS2Rs. For examples, amino acid derivatives such as γ-aminobutyric acid (GABA) and Nα,Nα-bis(carboxymethyl)-L-Lysine (BCML) blocked responses to quinine mediated by human TAS2R4. Probenecid inhibited responses to phenylthiocarbamide mediated by human TAS2R38. In this study, we investigated the effects of these human bitter receptor antagonists on behavioral lick responses of mice to elucidate whether these compounds also function as bitter taste blockers. In short-term (10 s) lick tests, concentration-dependent lick responses to bitter compounds (quinine-HCl, denatonium and phenylthiourea) were not affected by the addition of GABA or BCML. Probenecid reduced aversive lick responses to denatonium and phenylthiourea but not to quinine-HCl. In addition, taste cell responses to phenylthiourea were inhibited by probenecid. These results suggest some bitter antagonists of human TAS2Rs can work for bitter sense of mouse.
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Affiliation(s)
- Michimasa Masamoto
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan
| | - Yoshihiro Mitoh
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan
| | - Motoi Kobashi
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan
| | - Noriatsu Shigemura
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Ryusuke Yoshida
- Department of Oral Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8525, Japan.
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30
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Fotsing JR, Darmohusodo V, Patron AP, Ching BW, Brady T, Arellano M, Chen Q, Davis TJ, Liu H, Servant G, Zhang L, Williams M, Saganich M, Ditschun T, Tachdjian C, Karanewsky DS. Discovery and Development of S6821 and S7958 as Potent TAS2R8 Antagonists. J Med Chem 2020; 63:4957-4977. [PMID: 32330040 DOI: 10.1021/acs.jmedchem.0c00388] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In humans, bitter taste is mediated by 25 TAS2Rs. Many compounds, including certain active pharmaceutical ingredients, excipients, and nutraceuticals, impart their bitter taste (or in part) through TAS2R8 activation. However, effective TAS2R8 blockers that can either suppress or reduce the bitterness of these compounds have not been described. We are hereby reporting a series of novel 3-(pyrazol-4-yl) imidazolidine-2,4-diones as potent and selective TAS2R8 antagonists. In human sensory tests, S6821 and S7958, two of the most potent analogues from the series, demonstrated efficacy in blocking TAS2R8-mediated bitterness and were selected for development. Following data evaluation by expert panels of a number of national and multinational regulatory bodies, including the US, the EU, and Japan, S6821 and S7958 were approved as safe under conditions of intended use as bitter taste blockers.
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Affiliation(s)
- Joseph R Fotsing
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Vincent Darmohusodo
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Andrew P Patron
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Brett W Ching
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Thomas Brady
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Melissa Arellano
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Qing Chen
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Timothy J Davis
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Hanghui Liu
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Guy Servant
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Lan Zhang
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Mark Williams
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Michael Saganich
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Tanya Ditschun
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Catherine Tachdjian
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
| | - Donald S Karanewsky
- Firmenich SA, R&D North America, San Diego site, 4767 Nexus Centre Drive, San Diego, California 92121, United States
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31
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Stoeger V, Holik AK, Hölz K, Dingjan T, Hans J, Ley JP, Krammer GE, Niv MY, Somoza MM, Somoza V. Bitter-Tasting Amino Acids l-Arginine and l-Isoleucine Differentially Regulate Proton Secretion via T2R1 Signaling in Human Parietal Cells in Culture. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:3434-3444. [PMID: 31891507 DOI: 10.1021/acs.jafc.9b06285] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This study aimed at identifying whether the bitter-tasting amino acids l-arginine (l-ARG) and l-isoleucine (l-ILE) differentially regulate mechanisms of gastric acid secretion in human parietal cells (HGT-1 cells) via activation of bitter taste sensing receptors (T2Rs). In a first set of experiments, involvement of T2Rs in l-ARG and l-ILE-modulated proton secretion was demonstrated by co-treatment of HGT-1 cells with T2R antagonists. Subsequent whole genome screenings by means of cDNA arrays revealed T2R1 as a prominent target for both amino acids. Next, the functional role of T2R1 was verified by means of a T2R1 CRISPR-Cas9 knock-out approach. Here, the effect of l-ARG on proton secretion decreased by 65.7 ± 21.9% and the effect of l-ILE increased by 93.2 ± 24.1% in HGT-1 T2R1 ko versus HGT-1 wt cells (p < 0.05). Overall, our results indicate differential effects of l-ARG and l-ILE on proton secretion in HGT-1 cells and our molecular docking studies predict distinct binding for these amino acids in the binding site of T2R1. Further studies will elucidate whether the mechanism of differential effects involves structure-specific ligand-biased signaling of T2R1 or additional cellular targets.
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Affiliation(s)
| | | | | | - Tamir Dingjan
- Institute of Biochemistry, Food Science and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - Joachim Hans
- Symrise AG Global Innovation Cosmetic Ingredient Research, Research & Technology Flavors Division, P.O. Box 1253, Holzminden 37603, Germany
| | - Jakob P Ley
- Symrise AG Global Innovation Cosmetic Ingredient Research, Research & Technology Flavors Division, P.O. Box 1253, Holzminden 37603, Germany
| | - Gerhard E Krammer
- Symrise AG Global Innovation Cosmetic Ingredient Research, Research & Technology Flavors Division, P.O. Box 1253, Holzminden 37603, Germany
| | - Masha Y Niv
- Institute of Biochemistry, Food Science and Nutrition, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
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32
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Spaggiari G, Di Pizio A, Cozzini P. Sweet, umami and bitter taste receptors: State of the art of in silico molecular modeling approaches. Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2019.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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33
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Singh N, Shaik FA, Myal Y, Chelikani P. Chemosensory bitter taste receptors T2R4 and T2R14 activation attenuates proliferation and migration of breast cancer cells. Mol Cell Biochem 2020; 465:199-214. [PMID: 31894529 DOI: 10.1007/s11010-019-03679-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/14/2019] [Indexed: 12/16/2022]
Abstract
The emerging significance of the bitter taste receptors (T2Rs) role in the extraoral tissues alludes to their potential role in many pathophysiological conditions. The dysregulation of T2R expression and function in disease conditions has now been demonstrated in airways diseases, neurological disorders, and in some cancers. However, the role of T2Rs in the pathophysiology of breast cancer is unexplored thus far. Previously, we demonstrated differential expression of the 25 T2Rs in breast cancer (BC) cells. Based on our previous findings we selected two T2Rs, T2R4 and T2R14 for this work. The objective of the current study is to investigate the expression of T2R4 and T2R14 in BC clinical samples and to examine their physiological role using highly metastatic BC and non-cancerous cell lines. Using approaches, which involve receptor knockdown, pharmacological activation and biochemical assays we report that (i) T2R4 and T2R14 expression patterns are dissimilar, with decreased levels of T2R4 and increased levels of T2R14 in BC clinical samples compared to non-cancerous controls. (ii) Activation of T2Rs with their respective agonist elicited physiological responses in metastatic breast cancer cells, and no responses were seen in non-tumorigenic breast epithelial cells. (iii) Agonist activation of T2Rs (irrespective of T2R subtype) induced anti-proliferative, pro-apoptotic, and anti-migratory responses in highly metastatic breast cancer cells. Taken together, our findings demonstrate that the chemosensory T2R signaling network is involved in evoking physiological responses in the metastatic breast cancer cell line.
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Affiliation(s)
- Nisha Singh
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, Children's Hospital Research Institute of Manitoba, University of Manitoba, D319, 780 Bannatyne Avenue, Winnipeg, MB, R3E 0W3, Canada
| | - Feroz Ahmed Shaik
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, Children's Hospital Research Institute of Manitoba, University of Manitoba, D319, 780 Bannatyne Avenue, Winnipeg, MB, R3E 0W3, Canada
| | - Yvonne Myal
- Department of Pathology, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, Rady Faculty of Health Sciences, Dr. Gerald Niznick College of Dentistry, Children's Hospital Research Institute of Manitoba, University of Manitoba, D319, 780 Bannatyne Avenue, Winnipeg, MB, R3E 0W3, Canada.
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34
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Zhang C, Alashi AM, Singh N, Chelikani P, Aluko RE. Glycated Beef Protein Hydrolysates as Sources of Bitter Taste Modifiers. Nutrients 2019; 11:nu11092166. [PMID: 31509959 PMCID: PMC6770518 DOI: 10.3390/nu11092166] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 08/30/2019] [Accepted: 09/05/2019] [Indexed: 12/24/2022] Open
Abstract
Being averse to bitter taste is a common phenomenon for humans and other animals, which requires the pharmaceutical and food industries to source compounds that can block bitterness intensity and increase consumer acceptability. In this work, beef protein alcalase hydrolysates (BPAH) and chymotrypsin hydrolysates (BPCH) were reacted with glucose to initiate Maillard reactions that led to the formation of glycated or advanced glycation end products (AGEs), BPAH-AGEs and BPCH-AGEs, respectively. The degree of glycation was higher for the BPAH-AGEs (47-55%) than the BPCH-AGEs (30-38%). Analysis by an electronic tongue instrument showed that BPAH-AGEs and BPCH-AGEs had bitterness scores that were significantly (p < 0.05) less than quinine. The addition of BPAH-AGEs or BPCH-AGEs to quinine led to significant (p < 0.05) reductions (up to 38%) in bitterness intensity of quinine. The use of 3% hydrolysate to react with glucose yielded glycated peptides with a stronger ability to reduce quinine bitterness than when 1% was used. Calcium release from HEK293T cells stably expressing the T2R4 human bitter taste receptor was significantly (p < 0.05) attenuated by BPAH-AGEs (up to 96%) and BPCH-AGEs (up to 92%) when compared to the BPAH (62%) and BPCH (3%) or quinine (0%). We concluded that BPAH-AGEs and BPCH-AGEs may be used as bitter taste blockers to formulate better tasting foods.
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Affiliation(s)
- Chunlei Zhang
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Adeola M Alashi
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Nisha Singh
- 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
| | - 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
| | - Rotimi E Aluko
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
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35
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Shaik FA, Jaggupilli A, Chelikani P. Highly conserved intracellular H208 residue influences agonist selectivity in bitter taste receptor T2R14. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183057. [PMID: 31493373 DOI: 10.1016/j.bbamem.2019.183057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 11/19/2022]
Abstract
Bitter taste receptors (T2Rs) are a specialized class of cell membrane receptors of the G protein-coupled receptor family and perform a crucial role in chemosensation. The 25 T2Rs in humans are activated by structurally diverse ligands of plant, animal and microbial origin. The mechanisms of activation of these receptors are poorly understood. Therefore, identification of structural determinants of T2Rs that regulate its efficacy could be beneficial in understanding the molecular mechanisms of T2R activation. In this work, we characterized a highly conserved histidine (H208), present at TM5-ICL3 region of T2R14 and its role in agonist-induced T2R14 signaling. Surprisingly, mutation of the conserved H208 (H208A) did not result in increased basal activity of T2R14, in contrast to similar H206A mutation in T2R4 that showed constitutive or basal activity. However, H208A mutation in T2R14 resulted in an increase in agonist-induced efficacy for Flufenamic acid (FFA). Interestingly, H208A did not affect the potency of another T2R14 agonist Diphenhydramine (DPH). The H208R compensatory mutation showed FFA response similar to wild-type T2R14. Molecular modeling suggests a FFA-induced shift in TM3 and TM5 helices of H208A, which changes the network of interactions connecting TM5-ICL3-TM6. This report identifies a crucial residue on the intracellular surface of T2Rs that is involved in bitter ligand selectivity. It also highlights the varied roles carried out by some conserved residues in different T2Rs.
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Affiliation(s)
- Feroz Ahmed Shaik
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba, Winnipeg, MB, Canada.
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36
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Abstract
AbstractA major challenge in taste research is to overcome the flavour imperfections in food products and to build nutritious strategies to combat against obesity as well as other related metabolic syndromes. The field of molecular taste research and chemical senses has contributed to an enormous development in understanding the taste receptors and mechanisms of taste perception. Accordingly, the development of taste-modifying compounds or taste modulators that alter the perception of basic taste modalities has gained significant prominence in the recent past. The beneficial aspects of these substances are overwhelming while considering their potential taste-modifying properties. The objective of the present review is to provide an impression about the taste-modulating compounds and their distinctive taste-modifying properties with reference to their targets and proposed mechanisms of action. The present review also makes an effort to discuss the basic mechanism involved in oro-gustatory taste perception as well as on the effector molecules involved in signal transduction downstream to the activation of taste receptors.
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37
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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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Fierro F, Giorgetti A, Carloni P, Meyerhof W, Alfonso-Prieto M. Dual binding mode of "bitter sugars" to their human bitter taste receptor target. Sci Rep 2019; 9:8437. [PMID: 31186454 PMCID: PMC6560132 DOI: 10.1038/s41598-019-44805-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/22/2019] [Indexed: 12/21/2022] Open
Abstract
The 25 human bitter taste receptors (hTAS2Rs) are responsible for detecting bitter molecules present in food, and they also play several physiological and pathological roles in extraoral compartments. Therefore, understanding their ligand specificity is important both for food research and for pharmacological applications. Here we provide a molecular insight into the exquisite molecular recognition of bitter β-glycopyranosides by one of the members of this receptor subclass, hTAS2R16. Most of its agonists have in common the presence of a β-glycopyranose unit along with an extremely structurally diverse aglycon moiety. This poses the question of how hTAS2R16 can recognize such a large number of "bitter sugars". By means of hybrid molecular mechanics/coarse grained molecular dynamics simulations, here we show that the three hTAS2R16 agonists salicin, arbutin and phenyl-β-D-glucopyranoside interact with the receptor through a previously unrecognized dual binding mode. Such mechanism may offer a seamless way to fit different aglycons inside the binding cavity, while maintaining the sugar bound, similar to the strategy used by several carbohydrate-binding lectins. Our prediction is validated a posteriori by comparison with mutagenesis data and also rationalizes a wealth of structure-activity relationship data. Therefore, our findings not only provide a deeper molecular characterization of the binding determinants for the three ligands studied here, but also give insights applicable to other hTAS2R16 agonists. Together with our results for other hTAS2Rs, this study paves the way to improve our overall understanding of the structural determinants of ligand specificity in bitter taste receptors.
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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 Jülich, Jülich, Germany
- Department of Biology, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Alejandro Giorgetti
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich, Jülich, Germany
- Department of Biotechnology, University of Verona, Verona, Italy
- JARA-HPC, IAS-5/INM-9 Computational Biomedicine, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Paolo Carloni
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich, Jülich, Germany
- JARA-HPC, IAS-5/INM-9 Computational Biomedicine, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
- Department of Physics, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
- VNU Key Laboratory "Multiscale Simulation of Complex Systems", VNU University of Science, Vietnam National University, Hanoi, Vietnam
| | - Wolfgang Meyerhof
- Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Mercedes Alfonso-Prieto
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich, Jülich, Germany.
- JARA-HPC, IAS-5/INM-9 Computational Biomedicine, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany.
- Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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Itoigawa A, Hayakawa T, Suzuki-Hashido N, Imai H. A natural point mutation in the bitter taste receptor TAS2R16 causes inverse agonism of arbutin in lemur gustation. Proc Biol Sci 2019; 286:20190884. [PMID: 31161904 DOI: 10.1098/rspb.2019.0884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Bitter taste enables the detection of potentially harmful substances and is mediated by bitter taste receptors, TAS2Rs, in vertebrates. Few antagonists and inverse agonists of TAS2Rs have been identified, especially natural compounds. TAS2R16s in humans, apes and Old World monkeys (Catarrhini, Anthropoidea) recognize β-glucoside analogues as specific agonists. Here, we investigated responses of TAS2R16 to β-glucosides in non-anthropoid primates, namely lemurs (Lemuriformes, Strepsirrhini). Salicin acted as an agonist on lemur TAS2R16. Arbutin acted as an agonist in the ring-tailed lemur ( Lemur catta) but as an inverse agonist in black lemur ( Eulemur macaco) and black-and-white ruffed lemur ( Varecia variegata). We identified a strepsirrhine-specific amino acid substitution responsible for the inverse agonism of arbutin. In a food preference test, salicin bitterness was inhibited by arbutin in the black lemur. Structural modelling revealed this locus was important for a rearrangement of the intracellular end of transmembrane helix 7 (TM7). Accordingly, arbutin is the first known natural inverse agonist of TAS2Rs, contributing to our understanding of receptor-ligand interactions and the molecular basis of the unique feeding habit diversification in lemurs. Furthermore, the identification of a causal point mutation suggests that TAS2R can acquire functional changes according to feeding habits and environmental conditions.
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Affiliation(s)
- Akihiro Itoigawa
- 1 Molecular Biology Section, Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University , 41-2 Kanrin, Inuyama, Aichi 484-8506 , Japan.,3 Japan Society for the Promotion of Science , Kojimachi, Chiyoda-ku, Tokyo 102-0083 , Japan
| | - Takashi Hayakawa
- 2 Department of Wildlife Science (Nagoya Railroad Co., Ltd.), Primate Research Institute, Kyoto University , 41-2 Kanrin, Inuyama, Aichi 484-8506 , Japan.,4 Faculty of Environmental Earth Science, Hokkaido University , N10W5, Kita-ku, Sapporo, Hokkaido 060-0810 , Japan.,5 Japan Monkey Centre , 26 Inuyamakanrin, Inuyama, Aichi 484-0081 , Japan
| | - Nami Suzuki-Hashido
- 3 Japan Society for the Promotion of Science , Kojimachi, Chiyoda-ku, Tokyo 102-0083 , Japan.,6 Chubu University Academy of Emerging Sciences , 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 , Japan
| | - Hiroo Imai
- 1 Molecular Biology Section, Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University , 41-2 Kanrin, Inuyama, Aichi 484-8506 , Japan
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Alfonso-Prieto M, Giorgetti A, Carloni P. Multiscale simulations on human Frizzled and Taste2 GPCRs. Curr Opin Struct Biol 2019; 55:8-16. [PMID: 30933747 DOI: 10.1016/j.sbi.2019.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/19/2019] [Indexed: 01/24/2023]
Abstract
Recently, molecular dynamics simulations, from all atom and coarse grained to hybrid methods bridging the two scales, have provided exciting functional insights into class F (Frizzled and Taste2) GPCRs (about 40 members in humans). Findings include: (i) The activation of one member of the Frizzled receptors (FZD4) involves a bending of transmembrane helix TM7 far larger than that in class A GPCRs. (ii) The affinity of an anticancer drug targeting another member (Smoothened receptor) decreases in a specific drug-resistant variant, because the mutation ultimately disrupts the binding cavity and affects TM6. (iii) A novel two-state recognition mechanism explains the very large agonist diversity for at least one member of the Taste2 GPCRs, hTAS2R46.
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Affiliation(s)
- Mercedes Alfonso-Prieto
- Computational Biomedicine, Institute for Advanced Simulations IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich GmbH, Jülich, Germany; Cécile and Oskar Vogt Institute for Brain Research, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Alejandro Giorgetti
- Computational Biomedicine, Institute for Advanced Simulations IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich GmbH, Jülich, Germany; Department of Biotechnology, University of Verona, Verona, Italy
| | - Paolo Carloni
- Computational Biomedicine, Institute for Advanced Simulations IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich GmbH, Jülich, Germany; Department of Physics, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany; JARA Institute Molecular Neuroscience and Neuroimaging (INM-11), Forschungszentrum Jülich GmbH, Jülich, Germany; VNU Key Laboratory "Multiscale Simulation of Complex Systems", VNU University of Science, Vietnam National University, Hanoi, Viet Nam.
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41
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Xu Q, Singh N, Hong H, Yan X, Yu W, Jiang X, Chelikani P, Wu J. Hen protein-derived peptides as the blockers of human bitter taste receptors T2R4, T2R7 and T2R14. Food Chem 2019; 283:621-627. [PMID: 30722920 DOI: 10.1016/j.foodchem.2019.01.059] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/05/2018] [Accepted: 01/08/2019] [Indexed: 01/02/2023]
Abstract
Bitter sensation is mediated by various bitter taste receptors (T2Rs), thus T2R antagonists are actively explored. Our objective was to look for novel T2R blockers in hen protein hydrolysate (HPH). We screened the least bitter HPH fractions using electronic tongue, and analyzed their peptide sequences and calcium mobilization in HEK293T cells expressing T2Rs. The results showed that the HPH fractions with higher bitterness intensity had higher hydrophobicity, more hydrophobic amino acids, and more positively charged peptides, but fewer known umami peptides. The peptide fractions from the least bitter HPH fraction significantly inhibited quinine bitterness (P < 0.05), and also significantly inhibited quinine- or diphenhydramine-dependent calcium mobilization of HEK293T cells expressing human T2R4, T2R7, or T2R14 (P < 0.05). Among them, the first eluted (least bitter) peptide fraction showed the strongest bitter-inhibitory effect. In conclusion, HPH peptides are the blockers of T2R4, T2R7, and T2R14.
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Affiliation(s)
- Qingbiao Xu
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan 430070, China; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, Manitoba R3E 0W2, Canada
| | - Hui Hong
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Xianghua Yan
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan 430070, China; The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pig Precision Feeding and Feed Safety Technology, Wuhan 430070, China
| | - Wenlin Yu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Xu Jiang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Winnipeg, Manitoba R3E 0W2, Canada
| | - Jianping Wu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
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42
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Shaik FA, Medapati MR, Chelikani P. Cholesterol modulates the signaling of chemosensory bitter taste receptor T2R14 in human airway cells. Am J Physiol Lung Cell Mol Physiol 2019; 316:L45-L57. [PMID: 30358435 DOI: 10.1152/ajplung.00169.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bitter taste receptors (T2Rs) are a group of 25 chemosensory receptors expressed at significant levels in the human airways. In human airways, bitter taste receptor 14 (T2R14)-mediated physiological response in ameliorating obstructive airway disorders is an active area of investigation. Therefore, understanding various factors regulating the structure and function of T2R14 will be beneficial. We hypothesize that membrane lipids like cholesterol play a regulatory role in T2R14 signaling in airway cells. We confirmed the expression and signaling of T2R14 in primary human airway smooth muscle (HASM) cells and the human airway epithelial cell line (NuLi-1) using immunoblot analysis and intracellular calcium concentration mobilization experiments, respectively. Next, T2R14 signaling was examined in membrane cholesterol-altered environments by methyl-β-cyclodextrin or cholesterol oxidase treatments. In the cells analyzed, cholesterol depletion affected the agonist-induced T2R14 signaling, and cholesterol replenishment rescued its efficacy. An alternative approach for cholesterol depletion (with cholesterol oxidase pretreatment) also negatively affected the agonist potency at T2R14 in HASM cells. To understand the molecular mechanism of interaction between cholesterol and T2R14, we used site-directed mutagenesis coupled with functional assays and examined the role of putative cholesterol-binding motifs (CRAC and CARC) in T2R14. Functional characterization of wild-type and mutant T2R14 receptors suggests that amino acid residues K110, F236, and L239 are crucial in T2R14-cholesterol functional interaction. In conclusion, our results show that cholesterol influences the T2R14 signaling efficacy by forming direct interactions with the receptor and consequently plays a regulatory role in T2R14-mediated signaling in human airway cells.
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Affiliation(s)
- Feroz Ahmed Shaik
- Manitoba Chemosensory Biology Research Group, University of Manitoba, Manitoba, Canada.,Department of Oral Biology, University of Manitoba, Manitoba, Canada.,Children's Hospital Research Institute of Manitoba , Winnipeg, Manitoba , Canada
| | - Manoj Reddy Medapati
- Manitoba Chemosensory Biology Research Group, University of Manitoba, Manitoba, Canada.,Department of Oral Biology, University of Manitoba, Manitoba, Canada.,Children's Hospital Research Institute of Manitoba , Winnipeg, Manitoba , Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, University of Manitoba, Manitoba, Canada.,Department of Oral Biology, University of Manitoba, Manitoba, Canada.,Children's Hospital Research Institute of Manitoba , Winnipeg, Manitoba , Canada
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Singh K, Sona C, Ojha V, Singh M, Mishra A, Kumar A, Siddiqi MI, Tripathi RP, Yadav PN. Identification of dual role of piperazine-linked phenyl cyclopropyl methanone as positive allosteric modulator of 5-HT 2C and negative allosteric modulator of 5-HT 2B receptors. Eur J Med Chem 2018; 164:499-516. [PMID: 30622024 DOI: 10.1016/j.ejmech.2018.12.070] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/05/2018] [Accepted: 12/26/2018] [Indexed: 12/24/2022]
Abstract
Allosteric modulators of G-protein-coupled receptors have lately gained significant traction in drug discovery. Recent studies have shown that allosteric modulation of serotonin 2C receptor (5-HT2C) as a viable strategy for the treatment of various central nervous system (CNS) disorders. Considering the critical role of 5-HT2C in the modulation of appetite, a selective positive allosteric modulator (PAM) of 5-HT2C offers a new opportunity for anti-obesity therapeutic development. In this study, phenyl cyclopropyl-linked N-heterocycles were synthesized and evaluated at 5-HT2C for agonist and PAM activity. Our study shows that imidazole linked phenyl cyclopropyl methanones has PAM activity on both 5-HT2C and serotonin 2B receptor (5-HT2B). Interestingly, piperazine linked phenyl cyclopropyl methanones (58) was active as PAM of 5-HT2C (increased the Emax of 5-HT to 139%), and as negative allosteric modulator (NAM) of 5-HT2B (decreases EC50 of 5-HT 10 times without affecting Emax). Similar effect of compound 58 was observed with synthetic orthosteric agonist lorcaserin on 5-HT2B. Molecular docking study revealed that all active compounds were binding to the predicted allosteric site on 5-HT2C and shared a common interacting residues. Finally, compound 58 suppressed food intake in Sprague Dawley (SD) rats similar to lorcaserin after i.c.v. administration. Therefore, these results suggest that piperazine moiety is essential for dual activity (PAM & NAM) of compounds 58, and supports the hypothesis of 5-HT2C PAM for the treatment of obesity similar to the full agonist.
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Affiliation(s)
- Kartikey Singh
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Chandan Sona
- Pharmacology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110001, India
| | - Vikash Ojha
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Maninder Singh
- Computational Biology and Bioinformatics Unit, Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Ankita Mishra
- Pharmacology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Ajeet Kumar
- Pharmacology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Mohammad Imran Siddiqi
- Computational Biology and Bioinformatics Unit, Molecular and Structural Biology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Rama P Tripathi
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110001, India; National Institute of Pharmaceutical Education and Research Raebarely, New Transit Campus, Bijnor Road, Sarojani Nagar Near CRPF Base Camp, Lucknow, 226002, UP, India.
| | - Prem N Yadav
- Pharmacology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110001, India.
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Jaggupilli A, Singh N, De Jesus VC, Gounni MS, Dhanaraj P, Chelikani P. Chemosensory bitter taste receptors (T2Rs) are activated by multiple antibiotics. FASEB J 2018; 33:501-517. [PMID: 30011231 DOI: 10.1096/fj.201800521rr] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Many medications including antibiotics taste bitter. The potency of these antibiotics on the 25 bitter taste receptors (T2Rs) in humans remains poorly understood. Here we characterize by sensory and structure-function analyses how antibiotics frequently used to treat airway infections in cystic fibrosis activate multiple human T2Rs. The potency of the broad-spectrum antibiotics, tobramycin, levofloxacin, and azithromycin on the highly expressed T2Rs in airways, T2R4, T2R14, and T2R20 was pursued. The amino acids and structural features of T2R4, T2R14, and T2R20 important for antibiotic binding were characterized by mutational analysis in heterologous cell-based assays. Strikingly, extracellular loop 2 in T2Rs performs a key function in binding to antibiotics with contribution from residues in transmembrane helices. Our results suggest that different antibiotics activate multiple T2Rs with different potencies. An understanding of the nonantibiotic and physiologic effects mediated through T2Rs on the host cells is much needed.-Jaggupilli, A., Singh, N., De Jesus, V. C., Gounni, M. S., Dhanaraj, P., Chelikani, P. Chemosensory bitter taste receptors (T2Rs) are activated by multiple antibiotics.
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Affiliation(s)
- Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, Manitoba, Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, Manitoba, Canada
| | - Vivianne Cruz De Jesus
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, Manitoba, Canada
| | - Mohamed Soussi Gounni
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, Manitoba, Canada
| | - Premnath Dhanaraj
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, Manitoba, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, Manitoba, Canada
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45
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Jaggupilli A, Singh N, Jesus VCD, Duan K, Chelikani P. Characterization of the Binding Sites for Bacterial Acyl Homoserine Lactones (AHLs) on Human Bitter Taste Receptors (T2Rs). ACS Infect Dis 2018; 4:1146-1156. [PMID: 29799189 DOI: 10.1021/acsinfecdis.8b00094] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The 25 bitter taste receptors (T2Rs) in humans are novel players in mediating host-pathogen responses in the airways and innate immunity. The chemosensory T2Rs are expressed in different extraoral tissues and perform diverse pathophysiological roles from mediating bronchodilation to detecting bacterial infection in the airways. T2Rs were suggested to be activated by multiple bacterial quorum sensing molecules (QSMs). However, whether bacterial QSMs bind to T2Rs and the structural features on T2Rs has not yet been characterized. Here, we analyzed the taste sensory profiles of QSMs including acyl homoserine lactones (C4-AHL, C8-AHL, and 3-oxo-C12-AHL) and hydroxyquinolones (HHQ and NHQ) predominantly secreted by Gram-negative bacteria and characterized the candidate T2Rs interacting with different QSMs using structure-function approaches. The potency of the above QSMs for T2Rs significantly expressed in the airways, namely T2R4, T2R14, and T2R20, was characterized. 3-Oxo-C12-AHL activated T2R4, T2R14, and T2R20, while C8-AHL activated T2R4 and T2R14 with strong potency. The T2R amino acid residues involved in the interactions were characterized by molecular-model-guided site-directed mutagenesis. AHLs bind to a similar orthosteric site present on the extracellular surface in all three T2Rs with significant contributions from residues in extracellular loop 2. Our results reveal the mode of binding of AHLs for different T2Rs and provide biochemical insights into their interactions. This study will facilitate mechanistic studies aimed at understanding the role of these T2Rs as "sensors" of bacteria and in host-pathogen interactions.
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Affiliation(s)
- Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada
| | - Vivianne Cruz De Jesus
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada
| | - Kangmin Duan
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, University of Manitoba, Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada
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46
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Cherian S, Lee BS, Tucker RM, Lee K, Smutzer G. Toward Improving Medication Adherence: The Suppression of Bitter Taste in Edible Taste Films. Adv Pharmacol Sci 2018; 2018:8043837. [PMID: 30046304 PMCID: PMC6036852 DOI: 10.1155/2018/8043837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/06/2018] [Accepted: 04/16/2018] [Indexed: 01/23/2023] Open
Abstract
Bitter taste is aversive to humans, and many oral medications exhibit a bitter taste. Bitter taste can be suppressed by the use of inhibitors or by masking agents such as sucralose. Another approach is to encapsulate bitter tasting compounds in order to delay their release. This delayed release can permit the prior release of bitter masking agents. Suppression of bitter taste was accomplished by encapsulating a bitter taste stimulus in erodible stearic acid microspheres, and embedding these 5 µmeter diameter microspheres in pullulan films that contain sucralose and peppermint oil as masking agents, along with an encapsulated masking agent (sucralose). Psychophysical tests demonstrated that films which encapsulated both quinine and sucralose produced a significant and continuous sweet percept when compared to films without sucralose microspheres. Films with both quinine and sucralose microspheres also produced positive hedonic scores that did not differ from control films that contained only sucralose microspheres or only empty (blank) microspheres. The encapsulation of bitter taste stimuli in lipid microspheres, and embedding these microspheres in rapidly dissolving edible taste films that contain masking agents in both the film base and in microspheres, is a promising approach for diminishing the bitter taste of drugs and related compounds.
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Affiliation(s)
- Silvy Cherian
- Department of Biology, Temple University, 1900 N. 12th Street, Philadelphia, PA 19122, USA
| | - Brian Sang Lee
- Department of Biology, Temple University, 1900 N. 12th Street, Philadelphia, PA 19122, USA
| | - Robin M. Tucker
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, USA
| | - Kevin Lee
- Department of Biology, Temple University, 1900 N. 12th Street, Philadelphia, PA 19122, USA
| | - Gregory Smutzer
- Department of Biology, Temple University, 1900 N. 12th Street, Philadelphia, PA 19122, USA
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Zhang C, Alashi AM, Singh N, Liu K, Chelikani P, Aluko RE. Beef Protein-Derived Peptides as Bitter Taste Receptor T2R4 Blockers. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:4902-4912. [PMID: 29706068 DOI: 10.1021/acs.jafc.8b00830] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The aim of this work was to determine the T2R4 bitter taste receptor-blocking ability of enzymatic beef protein hydrolysates and identified peptide sequences. Beef protein was hydrolyzed with each of six commercial enzymes (alcalase, chymotrypsin, trypsin, pepsin, flavourzyme, and thermoase). Electronic tongue measurements showed that the hydrolysates had significantly ( p < 0.05) lower bitter scores than quinine. Addition of the hydrolysates to quinine led to reduced bitterness intensity of quinine with trypsin and pepsin hydrolysates being the most effective. Addition of the hydrolysates to HEK293T cells that heterologously express one of the bitter taste receptors (T2R4) showed alcalase, thermoase, pepsin, and trypsin hydrolysates as the most effective in reducing calcium mobilization. Eight peptides that were identified from the alcalase and chymotrypsin hydrolysates also suppressed quinine-dependent calcium release from T2R4 with AGDDAPRAVF and ETSARHL being the most effective. We conclude that short peptide lengths or the presence of multiple serine residues may not be desirable structural requirements for blocking quinine-dependent T2R4 activation.
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Freund JR, Mansfield CJ, Doghramji LJ, Adappa ND, Palmer JN, Kennedy DW, Reed DR, Jiang P, Lee RJ. Activation of airway epithelial bitter taste receptors by Pseudomonas aeruginosa quinolones modulates calcium, cyclic-AMP, and nitric oxide signaling. J Biol Chem 2018; 293:9824-9840. [PMID: 29748385 DOI: 10.1074/jbc.ra117.001005] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 04/17/2018] [Indexed: 12/12/2022] Open
Abstract
Bitter taste receptors (taste family 2 bitter receptor proteins; T2Rs), discovered in many tissues outside the tongue, have recently become potential therapeutic targets. We have shown previously that airway epithelial cells express several T2Rs that activate innate immune responses that may be important for treatment of airway diseases such as chronic rhinosinusitis. It is imperative to more clearly understand what compounds activate airway T2Rs as well as their full range of functions. T2R isoforms in airway motile cilia (T2R4, -14, -16, and -38) produce bactericidal levels of nitric oxide (NO) that also increase ciliary beating, promoting clearance of mucus and trapped pathogens. Bacterial quorum-sensing acyl-homoserine lactones activate T2Rs and stimulate these responses in primary airway cells. Quinolones are another type of quorum-sensing molecule used by Pseudomonas aeruginosa To elucidate whether bacterial quinolones activate airway T2Rs, we analyzed calcium, cAMP, and NO dynamics using a combination of fluorescent indicator dyes and FRET-based protein biosensors. T2R-transfected HEK293T cells, several lung epithelial cell lines, and primary sinonasal cells grown and differentiated at the air-liquid interface were tested with 2-heptyl-3-hydroxy-4-quinolone (known as Pseudomonas quinolone signal; PQS), 2,4-dihydroxyquinolone, and 4-hydroxy-2-heptylquinolone (HHQ). In HEK293T cells, PQS activated T2R4, -16, and -38, whereas HHQ activated T2R14. 2,4-Dihydroxyquinolone had no effect. PQS and HHQ increased calcium and decreased both baseline and stimulated cAMP levels in cultured and primary airway cells. In primary cells, PQS and HHQ activated levels of NO synthesis previously shown to be bactericidal. This study suggests that airway T2R-mediated immune responses are activated by bacterial quinolones as well as acyl-homoserine lactones.
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Affiliation(s)
- Jenna R Freund
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | | | | | - Nithin D Adappa
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | - James N Palmer
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | - David W Kennedy
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and
| | - Danielle R Reed
- the Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Peihua Jiang
- the Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Robert J Lee
- From the Departments of Otorhinolaryngology-Head and Neck Surgery and .,Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104 and
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Suess B, Brockhoff A, Meyerhof W, Hofmann T. The Odorant ( R)-Citronellal Attenuates Caffeine Bitterness by Inhibiting the Bitter Receptors TAS2R43 and TAS2R46. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:2301-2311. [PMID: 27569025 DOI: 10.1021/acs.jafc.6b03554] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sensory studies showed the volatile fraction of lemon grass and its main constituent, the odor-active citronellal, to significantly decrease the perceived bitterness of a black tea infusion as well as caffeine solutions. Seven citronellal-related derivatives were synthesized and shown to inhibit the perceived bitterness of caffeine in a structure-dependent manner. The aldehyde function at carbon 1, the ( R)-configuration of the methyl-branched carbon 3, and a hydrophobic carbon chain were found to favor the bitter inhibitory activity of citronellal; for example, even low concentrations of 25 ppm were observed to reduce bitterness perception of caffeine solution (6 mmol/L) by 32%, whereas ( R)-citronellic acid (100 pm) showed a reduction of only 21% and ( R)-citronellol (100 pm) was completely inactive. Cell-based functional experiments, conducted with the human bitter taste receptors TAS2R7, TAS2R10, TAS2R14, TAS2R43, and TAS2R46 reported to be sensitive to caffeine, revealed ( R)-citronellal to completely block caffeine-induced calcium signals in TAS2R43-expressing cells, and, to a lesser extent, in TAS2R46-expressing cells. Stimulation of TAS2R43-expressing cells with structurally different bitter agonists identified ( R)-citronellal as a general allosteric inhibitor of TAS2R43. Further structure/activity studies indicated 3-methyl-branched aliphatic aldehydes with a carbon chain of ≥4 C atoms as best TAS2R43 antagonists. Whereas odor-taste interactions have been mainly interpreted in the literature to be caused by a central neuronal integration of odors and tastes, rather than by peripheral events at the level of reception, the findings of this study open up a new dimension regarding the interaction of the two chemical senses.
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Affiliation(s)
- Barbara Suess
- Chair of Food Chemistry and Molecular Sensory Science , Technische Universität München , Lise-Meitner-Straße 34 , D-85354 Freising-Weihenstephan , Germany
| | - Anne Brockhoff
- Department of Molecular Genetics , German Institute of Human Nutrition (DIFE) Potsdam-Rehbrücke , Arthur-Scheunert-Allee 114-116 , 14558 Nuthetal , Germany
| | - Wolfgang Meyerhof
- Department of Molecular Genetics , German Institute of Human Nutrition (DIFE) Potsdam-Rehbrücke , Arthur-Scheunert-Allee 114-116 , 14558 Nuthetal , Germany
| | - Thomas Hofmann
- Chair of Food Chemistry and Molecular Sensory Science , Technische Universität München , Lise-Meitner-Straße 34 , D-85354 Freising-Weihenstephan , Germany
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50
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Behrens M, Meyerhof W. Vertebrate Bitter Taste Receptors: Keys for Survival in Changing Environments. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:2204-2213. [PMID: 28013542 DOI: 10.1021/acs.jafc.6b04835] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Research on bitter taste receptors has made enormous progress during recent years. Although in the early period after the discovery of this highly interesting receptor family special emphasis was placed on the deorphanization of mainly human bitter taste receptors, the research focus has shifted to sophisticated structure-function analyses, the discovery of small-molecule interactors, and the pharmacological profiling of nonhuman bitter taste receptors. These findings allowed novel perspectives on, for example, evolutionary and ecological questions that have arisen and that are discussed.
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Affiliation(s)
- Maik Behrens
- Department of Molecular Genetics , German Institute of Human Nutrition Potsdam-Rehbruecke , Arthur-Scheunert-Allee 114-116 , 14558 Nuthetal , Germany
| | - Wolfgang Meyerhof
- Department of Molecular Genetics , German Institute of Human Nutrition Potsdam-Rehbruecke , Arthur-Scheunert-Allee 114-116 , 14558 Nuthetal , Germany
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