1
|
Moribayashi T, Nakao Y, Ohtubo Y. Characteristics of A-type voltage-gated K + currents expressed on sour-sensing type III taste receptor cells in mice. Cell Tissue Res 2024; 396:353-369. [PMID: 38492001 PMCID: PMC11144136 DOI: 10.1007/s00441-024-03887-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/06/2024] [Indexed: 03/18/2024]
Abstract
Sour taste is detected by type III taste receptor cells that generate membrane depolarization with action potentials in response to HCl applied to the apical membranes. The shape of action potentials in type III cells exhibits larger afterhyperpolarization due to activation of transient A-type voltage-gated K+ currents. Although action potentials play an important role in neurotransmitter release, the electrophysiological features of A-type K+ currents in taste buds remain unclear. Here, we examined the electrophysiological properties of A-type K+ currents in mouse fungiform taste bud cells using in-situ whole-cell patch clamping. Type III cells were identified with SNAP-25 immunoreactivity and/or electrophysiological features of voltage-gated currents. Type III cells expressed A-type K+ currents which were completely inhibited by 10 mM TEA, whereas IP3R3-immunoreactive type II cells did not. The half-maximal activation and steady-state inactivation of A-type K+ currents were 17.9 ± 4.5 (n = 17) and - 11.0 ± 5.7 (n = 17) mV, respectively, which are similar to the features of Kv3.3 and Kv3.4 channels (transient and high voltage-activated K+ channels). The recovery from inactivation was well fitted with a double exponential equation; the fast and slow time constants were 6.4 ± 0.6 ms and 0.76 ± 0.26 s (n = 6), respectively. RT-PCR experiments suggest that Kv3.3 and Kv3.4 mRNAs were detected at the taste bud level, but not at single-cell levels. As the phosphorylation of Kv3.3 and Kv3.4 channels generally leads to the modulation of cell excitability, neuromodulator-mediated A-type K+ channel phosphorylation likely affects the signal transduction of taste.
Collapse
Affiliation(s)
- Takeru Moribayashi
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu, 808-0196, Japan
| | - Yoshiki Nakao
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu, 808-0196, Japan
| | - Yoshitaka Ohtubo
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Hibikino 2-4, Kitakyushu, 808-0196, Japan.
| |
Collapse
|
2
|
Perniss A, Boonen B, Tonack S, Thiel M, Poharkar K, Alnouri MW, Keshavarz M, Papadakis T, Wiegand S, Pfeil U, Richter K, Althaus M, Oberwinkler J, Schütz B, Boehm U, Offermanns S, Leinders-Zufall T, Zufall F, Kummer W. A succinate/SUCNR1-brush cell defense program in the tracheal epithelium. SCIENCE ADVANCES 2023; 9:eadg8842. [PMID: 37531421 PMCID: PMC10396310 DOI: 10.1126/sciadv.adg8842] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/29/2023] [Indexed: 08/04/2023]
Abstract
Host-derived succinate accumulates in the airways during bacterial infection. Here, we show that luminal succinate activates murine tracheal brush (tuft) cells through a signaling cascade involving the succinate receptor 1 (SUCNR1), phospholipase Cβ2, and the cation channel transient receptor potential channel subfamily M member 5 (TRPM5). Stimulated brush cells then trigger a long-range Ca2+ wave spreading radially over the tracheal epithelium through a sequential signaling process. First, brush cells release acetylcholine, which excites nearby cells via muscarinic acetylcholine receptors. From there, the Ca2+ wave propagates through gap junction signaling, reaching also distant ciliated and secretory cells. These effector cells translate activation into enhanced ciliary activity and Cl- secretion, which are synergistic in boosting mucociliary clearance, the major innate defense mechanism of the airways. Our data establish tracheal brush cells as a central hub in triggering a global epithelial defense program in response to a danger-associated metabolite.
Collapse
Affiliation(s)
- Alexander Perniss
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Brett Boonen
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
- Laboratory of Ion Channel Research, VIB Center for Brain and Disease, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Sarah Tonack
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Moritz Thiel
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Krupali Poharkar
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Mohamad Wessam Alnouri
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Maryam Keshavarz
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Tamara Papadakis
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Silke Wiegand
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Uwe Pfeil
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| | - Katrin Richter
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University, Giessen, Germany
| | - Mike Althaus
- Physiology Group, Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Burkhard Schütz
- Institute of Anatomy and Cell Biology, Philipps University Marburg, Marburg, Germany
| | - Ulrich Boehm
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), Saarland University, Homburg, Germany
| | - Stefan Offermanns
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Trese Leinders-Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Frank Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Wolfgang Kummer
- Institute of Anatomy and Cell Biology, German Center for Lung Research, Justus Liebig University Giessen; Giessen, Germany
- Excellence Cluster The Cardio-Pulmonary Institute, Justus Liebig University Giessen, Giessen, Germany
| |
Collapse
|
3
|
Ma Z, Paudel U, Foskett JK. Effects of temperature on action potentials and ion conductances in type II taste-bud cells. Am J Physiol Cell Physiol 2023; 325:C155-C171. [PMID: 37273235 PMCID: PMC10312327 DOI: 10.1152/ajpcell.00413.2022] [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: 09/06/2022] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 06/06/2023]
Abstract
Temperature strongly influences the intensity of taste, but it remains understudied despite its physiological, hedonic, and commercial implications. The relative roles of the peripheral gustatory and somatosensory systems innervating the oral cavity in mediating thermal effects on taste sensation and perception are poorly understood. Type II taste-bud cells, responsible for sensing sweet, bitter umami, and appetitive NaCl, release neurotransmitters to gustatory neurons by the generation of action potentials, but the effects of temperature on action potentials and the underlying voltage-gated conductances are unknown. Here, we used patch-clamp electrophysiology to explore the effects of temperature on acutely isolated type II taste-bud cell electrical excitability and whole cell conductances. Our data reveal that temperature strongly affects action potential generation, properties, and frequency and suggest that thermal sensitivities of underlying voltage-gated Na+ and K+ channel conductances provide a mechanism for how and whether voltage-gated Na+ and K+ channels in the peripheral gustatory system contribute to the influence of temperature on taste sensitivity and perception.NEW & NOTEWORTHY The temperature of food affects how it tastes. Nevertheless, the mechanisms involved are not well understood, particularly whether the physiology of taste-bud cells in the mouth is involved. Here we show that the electrical activity of type II taste-bud cells that sense sweet, bitter, and umami substances is strongly influenced by temperature. These results suggest a mechanism for the influence of temperature on the intensity of taste perception that resides in taste buds themselves.
Collapse
Affiliation(s)
- Zhongming Ma
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Usha Paudel
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - J Kevin Foskett
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| |
Collapse
|
4
|
Type II taste cells participate in mucosal immune surveillance. PLoS Biol 2023; 21:e3001647. [PMID: 36634039 PMCID: PMC9836272 DOI: 10.1371/journal.pbio.3001647] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 12/10/2022] [Indexed: 01/13/2023] Open
Abstract
The oral microbiome is second only to its intestinal counterpart in diversity and abundance, but its effects on taste cells remains largely unexplored. Using single-cell RNASeq, we found that mouse taste cells, in particular, sweet and umami receptor cells that express taste 1 receptor member 3 (Tas1r3), have a gene expression signature reminiscent of Microfold (M) cells, a central player in immune surveillance in the mucosa-associated lymphoid tissue (MALT) such as those in the Peyer's patch and tonsils. Administration of tumor necrosis factor ligand superfamily member 11 (TNFSF11; also known as RANKL), a growth factor required for differentiation of M cells, dramatically increased M cell proliferation and marker gene expression in the taste papillae and in cultured taste organoids from wild-type (WT) mice. Taste papillae and organoids from knockout mice lacking Spib (SpibKO), a RANKL-regulated transcription factor required for M cell development and regeneration on the other hand, failed to respond to RANKL. Taste papillae from SpibKO mice also showed reduced expression of NF-κB signaling pathway components and proinflammatory cytokines and attracted fewer immune cells. However, lipopolysaccharide-induced expression of cytokines was strongly up-regulated in SpibKO mice compared to their WT counterparts. Like M cells, taste cells from WT but not SpibKO mice readily took up fluorescently labeled microbeads, a proxy for microbial transcytosis. The proportion of taste cell subtypes are unaltered in SpibKO mice; however, they displayed increased attraction to sweet and umami taste stimuli. We propose that taste cells are involved in immune surveillance and may tune their taste responses to microbial signaling and infection.
Collapse
|
5
|
Dutta Banik D, Medler KF. Defining the role of TRPM4 in broadly responsive taste receptor cells. Front Cell Neurosci 2023; 17:1148995. [PMID: 37032837 PMCID: PMC10073513 DOI: 10.3389/fncel.2023.1148995] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
Peripheral taste receptor cells use multiple signaling pathways to transduce taste stimuli into output signals that are sent to the brain. We have previously identified a subpopulation of Type III taste cells that are broadly responsive (BR) and respond to multiple taste stimuli including bitter, sweet, umami, and sour. These BR cells use a PLCβ3/IP3R1 signaling pathway to detect bitter, sweet, and umami stimuli and use a separate pathway to detect sour. Currently, the downstream targets of the PLCβ3 signaling pathway are unknown. Here we identify TRPM4, a monovalent selective TRP channel, as an important downstream component in this signaling pathway. Using live cell imaging on isolated taste receptor cells from mice, we show that inhibition of TRPM4 abolished the taste-evoked sodium responses and significantly reduced the taste-evoked calcium responses in BR cells. Since BR cells are a subpopulation of Type III taste cells, they have conventional chemical synapses that require the activation of voltage-gated calcium channels (VGCCs) to cause neurotransmitter release. We found that TRPM4-dependent membrane depolarization selectively activates L-type VGCCs in these cells. The calcium influx through L-type VGCCs also generates a calcium-induced calcium release (CICR) via ryanodine receptors that enhances TRPM4 activity. Together these signaling events amplify the initial taste response to generate an appropriate output signal.
Collapse
|
6
|
Huang H, Fang Y, Jiang M, Zhang Y, Biermann J, Melms JC, Danielsson JA, Yang Y, Qiang L, Liu J, Zhou Y, Wang M, Hu Z, Wang TC, Saqi A, Sun J, Matsumoto I, Cardoso WV, Emala CW, Zhu J, Izar B, Mou H, Que J. Contribution of Trp63CreERT2-labeled cells to alveolar regeneration is independent of tuft cells. eLife 2022; 11:e78217. [PMID: 36129169 PMCID: PMC9553211 DOI: 10.7554/elife.78217] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 09/18/2022] [Indexed: 11/13/2022] Open
Abstract
Viral infection often causes severe damage to the lungs, leading to the appearance of ectopic basal cells (EBCs) and tuft cells in the lung parenchyma. Thus far, the roles of these ectopic epithelial cells in alveolar regeneration remain controversial. Here, we confirm that the ectopic tuft cells are originated from EBCs in mouse models and COVID-19 lungs. The differentiation of tuft cells from EBCs is promoted by Wnt inhibition while suppressed by Notch inhibition. Although progenitor functions have been suggested in other organs, pulmonary tuft cells don't proliferate or give rise to other cell lineages. Consistent with previous reports, Trp63CreERT2 and KRT5-CreERT2-labeled ectopic EBCs do not exhibit alveolar regeneration potential. Intriguingly, when tamoxifen was administrated post-viral infection, Trp63CreERT2 but not KRT5-CreERT2 labels islands of alveolar epithelial cells that are negative for EBC biomarkers. Furthermore, germline deletion of Trpm5 significantly increases the contribution of Trp63CreERT2-labeled cells to the alveolar epithelium. Although Trpm5 is known to regulate tuft cell development, complete ablation of tuft cell production fails to improve alveolar regeneration in Pou2f3-/- mice, implying that Trpm5 promotes alveolar epithelial regeneration through a mechanism independent of tuft cells.
Collapse
Affiliation(s)
- Huachao Huang
- Columbia Center for Human Development, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
- Division of Digestive and Liver Diseases, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
| | - Yinshan Fang
- Columbia Center for Human Development, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
- Division of Digestive and Liver Diseases, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
| | - Ming Jiang
- Institute of Genetics, the Children's Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Yihan Zhang
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
| | - Jana Biermann
- Division of Hematology/Oncology, Department of Medicine, Columbia University Irving Medical CenterNew YorkUnited States
- Columbia Center for Translational Immunology, Columbia University Irving Medical CenterNew YorkUnited States
| | - Johannes C Melms
- Division of Hematology/Oncology, Department of Medicine, Columbia University Irving Medical CenterNew YorkUnited States
- Columbia Center for Translational Immunology, Columbia University Irving Medical CenterNew YorkUnited States
| | - Jennifer A Danielsson
- Department of Anesthesiology, Columbia University Irving Medical CenterNew YorkUnited States
| | - Ying Yang
- Program in Epithelial Biology, Stanford University School of MedicineStanfordUnited States
| | - Li Qiang
- Department of Pathology & Cell Biology, Columbia University Medical CenterNew YorkUnited States
| | - Jia Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of SciencesWuhanChina
| | - Yiwu Zhou
- Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and TechnologyWuhanChina
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of SciencesWuhanChina
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of SciencesWuhanChina
| | - Timothy C Wang
- Division of Digestive and Liver Diseases, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
| | - Anjali Saqi
- Department of Pathology & Cell Biology, Columbia University Medical CenterNew YorkUnited States
| | - Jie Sun
- Carter Immunology Center, the University of VirginiaCharlottesvilleUnited States
| | | | - Wellington V Cardoso
- Columbia Center for Human Development, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
| | - Charles W Emala
- Department of Anesthesiology, Columbia University Irving Medical CenterNew YorkUnited States
| | - Jian Zhu
- Department of Pathology, Ohio State University College of MedicineColumbusUnited States
| | - Benjamin Izar
- Division of Hematology/Oncology, Department of Medicine, Columbia University Irving Medical CenterNew YorkUnited States
- Columbia Center for Translational Immunology, Columbia University Irving Medical CenterNew YorkUnited States
| | - Hongmei Mou
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Harvard Medical SchoolBostonUnited States
| | - Jianwen Que
- Columbia Center for Human Development, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
- Division of Digestive and Liver Diseases, Department of Medicine, Columbia University Medical CenterNew YorkUnited States
| |
Collapse
|
7
|
Cherkashin AP, Rogachevskaja OA, Kabanova NV, Kotova PD, Bystrova MF, Kolesnikov SS. Taste Cells of the Type III Employ CASR to Maintain Steady Serotonin Exocytosis at Variable Ca 2+ in the Extracellular Medium. Cells 2022; 11:cells11081369. [PMID: 35456048 PMCID: PMC9030112 DOI: 10.3390/cells11081369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 12/17/2022] Open
Abstract
Type III taste cells are the only taste bud cells which express voltage-gated (VG) Ca2+ channels and employ Ca2+-dependent exocytosis to release neurotransmitters, particularly serotonin. The taste bud is a tightly packed cell population, wherein extracellular Ca2+ is expected to fluctuate markedly due to the electrical activity of taste cells. It is currently unclear whether the Ca2+ entry-driven synapse in type III cells could be reliable enough at unsteady extracellular Ca2. Here we assayed depolarization-induced Ca2+ signals and associated serotonin release in isolated type III cells at varied extracellular Ca2+. It turned out that the same depolarizing stimulus elicited invariant Ca2+ signals in type III cells irrespective of bath Ca2+ varied within 0.5–5 mM. The serotonin release from type III cells was assayed with the biosensor approach by using HEK-293 cells co-expressing the recombinant 5-HT4 receptor and genetically encoded cAMP sensor Pink Flamindo. Consistently with the weak Ca2+ dependence of intracellular Ca2+ transients produced by VG Ca2+ entry, depolarization-triggered serotonin secretion varied negligibly with bath Ca2+. The evidence implicated the extracellular Ca2+-sensing receptor in mediating the negative feedback mechanism that regulates VG Ca2+ entry and levels off serotonin release in type III cells at deviating Ca2+ in the extracellular medium.
Collapse
|
8
|
Virginio C, Aldegheri L, Nola S, Brodbeck D, Brault L, Raveglia LF, Barilli A, Sabat M, Myers R. Identification of positive modulators of TRPM5 channel from a high-throughput screen using a fluorescent membrane potential assay. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:55-64. [PMID: 35058176 DOI: 10.1016/j.slasd.2021.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transient Receptor Potential Melastatin 5 (TRPM5) is an intracellular calcium-activated cation-selective ion channel expressed in a variety of cell types. Dysfunction of this channel has recently been implied in a range of disease states including diabetes, enteric infections, inflammatory responses, parasitic infection and other pathologies. However, to date, agonists and positive modulators of this channel with sufficient selectivity to enable target validation studies have not been described, limiting the evaluation of TRPM5 biology and its potential as a drug target. We developed a high-throughput assay using a fluorescent membrane potential dye and a medium- and high-throughput electrophysiology assay using QPatch HTX and SyncroPatch 384PE. By employing these assays, we conducted a primary screening campaign and identified hit compounds as TRPM5 channel positive modulators. An initial selectivity profile confirmed hit selectivity to TRPM5 and is presented here. These small molecule TRPM5 compounds have a high potential both as early tool compounds to enable pharmacological studies of TRPM5 and as starting points for the development of potent, selective TRPM5 openers or positive modulators as novel drugs targeting several pathological states.
Collapse
Affiliation(s)
- Caterina Virginio
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy.
| | - Laura Aldegheri
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy
| | - Selena Nola
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy
| | - Daniela Brodbeck
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy
| | - Laurent Brault
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy
| | - Luca F Raveglia
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy
| | - Alessio Barilli
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, 37135 Verona, Italy
| | - Mark Sabat
- Takeda Pharmaceuticals, 9625 Towne Centre Drive, San Diego, CA 92121, United States
| | - Richard Myers
- Takeda Pharmaceuticals, 9625 Towne Centre Drive, San Diego, CA 92121, United States
| |
Collapse
|
9
|
Barr J, Gentile ME, Lee S, Kotas ME, Fernanda de Mello Costa M, Holcomb NP, Jaquish A, Palashikar G, Soewignjo M, McDaniel M, Matsumoto I, Margolskee R, Von Moltke J, Cohen NA, Sun X, Vaughan AE. Injury-induced pulmonary tuft cells are heterogenous, arise independent of key Type 2 cytokines, and are dispensable for dysplastic repair. eLife 2022; 11:78074. [PMID: 36073526 PMCID: PMC9553214 DOI: 10.7554/elife.78074] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 09/07/2022] [Indexed: 01/07/2023] Open
Abstract
While the lung bears significant regenerative capacity, severe viral pneumonia can chronically impair lung function by triggering dysplastic remodeling. The connection between these enduring changes and chronic disease remains poorly understood. We recently described the emergence of tuft cells within Krt5+ dysplastic regions after influenza injury. Using bulk and single-cell transcriptomics, we characterized and delineated multiple distinct tuft cell populations that arise following influenza clearance. Distinct from intestinal tuft cells which rely on Type 2 immune signals for their expansion, neither IL-25 nor IL-4ra signaling are required to drive tuft cell development in dysplastic/injured lungs. In addition, tuft cell expansion occurred independently of type I or type III interferon signaling. Furthermore, tuft cells were also observed upon bleomycin injury, suggesting that their development may be a general response to severe lung injury. While intestinal tuft cells promote growth and differentiation of surrounding epithelial cells, in the lungs of tuft cell deficient mice, Krt5+ dysplasia still occurs, goblet cell production is unchanged, and there remains no appreciable contribution of Krt5+ cells into more regionally appropriate alveolar Type 2 cells. Together, these findings highlight unexpected differences in signals necessary for murine lung tuft cell amplification and establish a framework for future elucidation of tuft cell functions in pulmonary health and disease.
Collapse
Affiliation(s)
- Justinn Barr
- Department of Pediatrics, University of California, San DiegoSan DiegoUnited States
| | - Maria Elena Gentile
- Department of Biomedical Sciences, School of Veterinary Medicine, University of PennsylvaniaPhiladelphiaUnited States,Institute for Regenerative Medicine, University of PennsylvaniaPhiladelphiaUnited States,Lung Biology Institute, University of PennsylvaniaPhiladelphiaUnited States
| | - Sunyoung Lee
- Department of Pediatrics, University of California, San DiegoSan DiegoUnited States
| | - Maya E Kotas
- Division of Pulmonary, Critical Care, Allergy & Sleep Medicine, University of California, San FranciscoSan FranciscoUnited States
| | - Maria Fernanda de Mello Costa
- Department of Biomedical Sciences, School of Veterinary Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Nicolas P Holcomb
- Department of Biomedical Sciences, School of Veterinary Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Abigail Jaquish
- Department of Pediatrics, University of California, San DiegoSan DiegoUnited States
| | - Gargi Palashikar
- Department of Biomedical Sciences, School of Veterinary Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Marcella Soewignjo
- Department of Biomedical Sciences, School of Veterinary Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Margaret McDaniel
- Department of Immunology, University of WashingtonSeattleUnited States
| | | | | | - Jakob Von Moltke
- Department of Immunology, University of WashingtonSeattleUnited States
| | - Noam A Cohen
- Monell Chemical Senses CenterPhiladelphiaUnited States,Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Perelman School of MedicinePhiladelphiaUnited States,Corporal Michael J. Crescenz Veterans Administration Medical Center Surgical ServicePhiladelphiaUnited States
| | - Xin Sun
- Division of Biological Sciences, University of California, San DiegoSan DiegoUnited States
| | - Andrew E Vaughan
- Department of Biomedical Sciences, School of Veterinary Medicine, University of PennsylvaniaPhiladelphiaUnited States,Institute for Regenerative Medicine, University of PennsylvaniaPhiladelphiaUnited States,Lung Biology Institute, University of PennsylvaniaPhiladelphiaUnited States
| |
Collapse
|
10
|
Zhen H, Zheng M, Song Q, Liu H, Yuan Z, Cao Z, Zhao B. U73122 and m-3M3FBS Regulate the GABAergic Neuron Regeneration via PLCβ in Planarian Dugesia japonica. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421040188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
11
|
Mizuta H, Kumamoto N, Ugawa S, Yamamoto T. Additive Effects of L-Ornithine on Preferences to Basic Taste Solutions in Mice. Nutrients 2021; 13:3749. [PMID: 34836006 PMCID: PMC8623908 DOI: 10.3390/nu13113749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/15/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022] Open
Abstract
In addition to the taste receptors corresponding to the six basic taste qualities-sweet, salty, sour, bitter, umami, and fatty-another type of taste receptor, calcium-sensing receptor (CaSR), is found in taste-bud cells. CaSR is called the 'kokumi' receptor because its agonists increase sweet, salty and umami tastes to induce 'koku', a Japanese word meaning the enhancement of flavor characters such as thickness, mouthfulness, and continuity. Koku is an important factor for enhancing food palatability. However, it is not well known whether other kokumi-receptors and substances exist. Here, we show that ornithine (L-ornithine but not D-ornithine) at low concentrations that do not elicit a taste of its own, enhances preferences to sweet, salty, umami, and fat taste solutions in mice. Increased preference to monosodium glutamate (MSG) was the most dominant effect. Antagonists of G-protein-coupled receptor family C group 6 subtype A (GPRC6A) abolished the additive effect of ornithine on MSG solutions. The additive effects of ornithine on taste stimuli are thought to occur in the oral cavity, and are not considered post-oral events because ornithine's effects were confirmed in a brief-exposure test. Moreover, the additive effects of ornithine and the action of the antagonist were verified in electrophysiological taste nerve responses. Immunohistochemical analysis implied that GPRC6A was expressed in subsets of type II and type III taste cells of mouse circumvallate papillae. These results are in good agreement with those reported for taste modulation involving CaSR and its agonists. The present study suggests that ornithine is a kokumi substance and GPRC6A is a newly identified kokumi receptor.
Collapse
Affiliation(s)
- Haruno Mizuta
- Department of Nutrition, Faculty of Health Sciences, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan;
| | - Natsuko Kumamoto
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (N.K.); (S.U.)
| | - Shinya Ugawa
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan; (N.K.); (S.U.)
| | - Takashi Yamamoto
- Department of Nutrition, Faculty of Health Sciences, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan;
- Health Science Research Center, Kio University, 4-2-4 Umami-naka, Koryo, Kitakatsuragi, Nara 635-0832, Japan
| |
Collapse
|
12
|
Yoshida Y, Kawabata F, Nishimura S, Tabata S. Overlapping distributions of mammalian types I, II, and III taste cell markers in chicken taste buds. Biochem Biophys Res Commun 2021; 570:162-168. [PMID: 34284142 DOI: 10.1016/j.bbrc.2021.07.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/01/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022]
Abstract
Mammalian taste buds comprise types I, II, and III taste cells, with each type having specific characteristics: glia-like supporting cells (type I), taste receptor cells (type II), and presynaptic cells (type III). In this study, to characterize the peripheral taste-sensing systems in chickens, we analyzed the distributions of the mammalian types I, II, and III taste cell markers in chicken taste buds: glutamate-aspartate transporter (GLAST) for type I; taste receptor type 1 members 1 and 3 (T1R1 and T1R3), taste receptor type 2 member 7 (T2R7), and α-gustducin for type II; and synaptosomal protein 25 (SNAP25) and neural cell adhesion molecule (NCAM) for type III. We found that most GLAST+ taste cells expressed α-gustducin and SNAP25 and that high percentages of T1R3+ or α-gustducin+ taste cells expressed SNAP25 and NCAM. These results demonstrated a unique subset of chicken taste cells expressing multiple taste cell type marker proteins. Taken together, these results provide new insights into the taste-sensing mechanisms in vertebrate taste buds.
Collapse
Affiliation(s)
- Yuta Yoshida
- Department of Food and Life Sciences, College of Agriculture, Ibaraki University, Ami, Japan
| | - Fuminori Kawabata
- Physiology of Domestic Animals, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan.
| | - Shotaro Nishimura
- Laboratory of Functional Anatomy, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Shoji Tabata
- Laboratory of Functional Anatomy, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| |
Collapse
|
13
|
Guarascio DM, Gonzalez-Velandia KY, Hernandez-Clavijo A, Menini A, Pifferi S. Functional expression of TMEM16A in taste bud cells. J Physiol 2021; 599:3697-3714. [PMID: 34089532 PMCID: PMC8361675 DOI: 10.1113/jp281645] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 06/04/2021] [Indexed: 12/14/2022] Open
Abstract
Key points Taste transduction occurs in taste buds in the tongue epithelium. The Ca2+‐activated Cl– channels TMEM16A and TMEM16B play relevant physiological roles in several sensory systems. Here, we report that TMEM16A, but not TMEM16B, is expressed in the apical part of taste buds. Large Ca2+‐activated Cl− currents blocked by Ani‐9, a selective inhibitor of TMEM16A, are measured in type I taste cells but not in type II or III taste cells. ATP indirectly activates Ca2+‐activated Cl– currents in type I cells through TMEM16A channels. These results indicate that TMEM16A is functional in type I taste cells and contribute to understanding the largely unknown physiological roles of these cells.
Abstract The Ca2+‐activated Cl– channels TMEM16A and TMEM16B have relevant roles in many physiological processes including neuronal excitability and regulation of Cl– homeostasis. Here, we examined the presence of Ca2+‐activated Cl– channels in taste cells of mouse vallate papillae by using immunohistochemistry and electrophysiological recordings. By using immunohistochemistry we showed that only TMEM16A, and not TMEM16B, was expressed in taste bud cells where it largely co‐localized with the inwardly rectifying K+ channel KNCJ1 in the apical part of type I cells. By using whole‐cell patch‐clamp recordings in isolated cells from taste buds, we measured an average current of −1083 pA at −100 mV in 1.5 μm Ca2+ and symmetrical Cl– in type I cells. Ion substitution experiments and blockage by Ani‐9, a specific TMEM16A channel blocker, indicated that Ca2+ activated anionic currents through TMEM16A channels. We did not detect any Ca2+‐activated Cl– currents in type II or III taste cells. ATP is released by type II cells in response to various tastants and reaches type I cells where it is hydrolysed by ecto‐ATPases. Type I cells also express P2Y purinergic receptors and stimulation of type I cells with extracellular ATP produced large Ca2+‐activated Cl− currents blocked by Ani‐9, indicating a possible role of TMEM16A in ATP‐mediated signalling. These results provide a definitive demonstration that TMEM16A‐mediated currents are functional in type I taste cells and provide a foundation for future studies investigating physiological roles for these often‐neglected taste cells. Taste transduction occurs in taste buds in the tongue epithelium. The Ca2+‐activated Cl– channels TMEM16A and TMEM16B play relevant physiological roles in several sensory systems. Here, we report that TMEM16A, but not TMEM16B, is expressed in the apical part of taste buds. Large Ca2+‐activated Cl− currents blocked by Ani‐9, a selective inhibitor of TMEM16A, are measured in type I taste cells but not in type II or III taste cells. ATP indirectly activates Ca2+‐activated Cl– currents in type I cells through TMEM16A channels. These results indicate that TMEM16A is functional in type I taste cells and contribute to understanding the largely unknown physiological roles of these cells.
Collapse
Affiliation(s)
- Domenico M Guarascio
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, 34136, Italy
| | | | - Andres Hernandez-Clavijo
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, 34136, Italy
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, 34136, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, 34136, Italy.,Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, 60126, Italy
| |
Collapse
|
14
|
von Molitor E, Riedel K, Krohn M, Hafner M, Rudolf R, Cesetti T. Sweet Taste Is Complex: Signaling Cascades and Circuits Involved in Sweet Sensation. Front Hum Neurosci 2021; 15:667709. [PMID: 34239428 PMCID: PMC8258107 DOI: 10.3389/fnhum.2021.667709] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 05/20/2021] [Indexed: 12/13/2022] Open
Abstract
Sweetness is the preferred taste of humans and many animals, likely because sugars are a primary source of energy. In many mammals, sweet compounds are sensed in the tongue by the gustatory organ, the taste buds. Here, a group of taste bud cells expresses a canonical sweet taste receptor, whose activation induces Ca2+ rise, cell depolarization and ATP release to communicate with afferent gustatory nerves. The discovery of the sweet taste receptor, 20 years ago, was a milestone in the understanding of sweet signal transduction and is described here from a historical perspective. Our review briefly summarizes the major findings of the canonical sweet taste pathway, and then focuses on molecular details, about the related downstream signaling, that are still elusive or have been neglected. In this context, we discuss evidence supporting the existence of an alternative pathway, independent of the sweet taste receptor, to sense sugars and its proposed role in glucose homeostasis. Further, given that sweet taste receptor expression has been reported in many other organs, the physiological role of these extraoral receptors is addressed. Finally, and along these lines, we expand on the multiple direct and indirect effects of sugars on the brain. In summary, the review tries to stimulate a comprehensive understanding of how sweet compounds signal to the brain upon taste bud cells activation, and how this gustatory process is integrated with gastro-intestinal sugar sensing to create a hedonic and metabolic representation of sugars, which finally drives our behavior. Understanding of this is indeed a crucial step in developing new strategies to prevent obesity and associated diseases.
Collapse
Affiliation(s)
- Elena von Molitor
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| | | | | | - Mathias Hafner
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Tiziana Cesetti
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| |
Collapse
|
15
|
Qin Y, Sukumaran SK, Margolskee RF. Nkx2-2 expressing taste cells in endoderm-derived taste papillae are committed to the type III lineage. Dev Biol 2021; 477:232-240. [PMID: 34097879 DOI: 10.1016/j.ydbio.2021.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/10/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
In mammals, multiple cell-signaling pathways and transcription factors regulate development of the embryonic taste system and turnover of taste cells in the adult stage. Using single-cell RNA-Seq of mouse taste cells, we found that the homeobox-containing transcription factor Nkx2-2, a target of the Sonic Hedgehog pathway and a key regulator of the development and regeneration of multiple cell types in the body, is highly expressed in type III taste cells but not in type II or taste stem cells. Using in situ hybridization and immunostaining, we confirmed that Nkx2-2 is expressed specifically in type III taste cells in the endoderm-derived circumvallate and foliate taste papillae but not in the ectoderm-derived fungiform papillae. Lineage tracing revealed that Nkx2-2-expressing cells differentiate into type III, but not type II or type I cells in circumvallate and foliate papillae. Neonatal Nkx2-2-knockout mice did not express key type III taste cell marker genes, while the expression of type II and type I taste cell marker genes were unaffected in these mice. Our findings indicate that Nkx2-2-expressing cells are committed to the type III lineage and that Nkx2-2 may be critical for the development of type III taste cells in the posterior tongue, thus illustrating a key difference in the mechanism of type III cell lineage specification between ectoderm- and endoderm-derived taste fields.
Collapse
Affiliation(s)
- Yumei Qin
- School of Food Science and Bioengineering, Zhejiang Gongshang University, Hangzhou, PR China; Monell Chemical Senses Center, Philadelphia, PA, USA
| | - Sunil K Sukumaran
- Monell Chemical Senses Center, Philadelphia, PA, USA; Present Address: Department of Nutrition and Health Sciences, University of Nebraska- Lincoln, Lincoln, NE, USA.
| | | |
Collapse
|
16
|
Type II/III cell composition and NCAM expression in taste buds. Cell Tissue Res 2021; 385:557-570. [PMID: 33942154 DOI: 10.1007/s00441-021-03452-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/15/2021] [Indexed: 10/21/2022]
Abstract
Taste buds are localized in fungiform (FF), foliate (FL), and circumvallate (CV) papillae on the tongue, and taste buds also occur on the soft palate (SP). Mature elongate cells within taste buds are constantly renewed from stem cells and classified into three cell types, Types I, II, and III. These cell types are generally assumed to reside in respective taste buds in a particular ratio corresponding to taste regions. A variety of cell-type markers were used to analyze taste bud cells. NCAM is the first established marker for Type III cells and is still often used. However, NCAM was examined mainly in the CV, but not sufficiently in other regions. Furthermore, our previous data suggested that NCAM may be transiently expressed in the immature stage of Type II cells. To precisely assess NCAM expression as a Type III cell marker, we first examined Type II and III cell-type markers, IP3R3 and CA4, respectively, and then compared NCAM with them using whole-mount immunohistochemistry. IP3R3 and CA4 were segregated from each other, supporting the reliability of these markers. The ratio between Type II and III cells varied widely among taste buds in the respective regions (Pearson's r = 0.442 [CV], 0.279 [SP], and - 0.011 [FF]), indicating that Type II and III cells are contained rather independently in respective taste buds. NCAM immunohistochemistry showed that a subset of taste bud cells were NCAM(+)CA4(-). While NCAM(+)CA4(-) cells were IP3R3(-) in the CV, the majority of them were IP3R3(+) in the SP and FF.
Collapse
|
17
|
Barilli A, Aldegheri L, Bianchi F, Brault L, Brodbeck D, Castelletti L, Feriani A, Lingard I, Myers R, Nola S, Piccoli L, Pompilio D, Raveglia LF, Salvagno C, Tassini S, Virginio C, Sabat M. From High-Throughput Screening to Target Validation: Benzo[ d]isothiazoles as Potent and Selective Agonists of Human Transient Receptor Potential Cation Channel Subfamily M Member 5 Possessing In Vivo Gastrointestinal Prokinetic Activity in Rodents. J Med Chem 2021; 64:5931-5955. [PMID: 33890770 DOI: 10.1021/acs.jmedchem.1c00065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transient receptor potential cation channel subfamily M member 5 (TRPM5) is a nonselective monovalent cation channel activated by intracellular Ca2+ increase. Within the gastrointestinal system, TRPM5 is expressed in the stoma, small intestine, and colon. In the search for a selective agonist of TRPM5 possessing in vivo gastrointestinal prokinetic activity, a high-throughput screening was performed and compound 1 was identified as a promising hit. Hit validation and hit to lead activities led to the discovery of a series of benzo[d]isothiazole derivatives. Among these, compounds 61 and 64 showed nanomolar activity and excellent selectivity (>100-fold) versus related cation channels. The in vivo drug metabolism and pharmacokinetic profile of compound 64 was found to be ideal for a compound acting locally at the intestinal level, with minimal absorption into systemic circulation. Compound 64 was tested in vivo in a mouse motility assay at 100 mg/kg, and demonstrated increased prokinetic activity.
Collapse
Affiliation(s)
- Alessio Barilli
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Laura Aldegheri
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Federica Bianchi
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Laurent Brault
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Daniela Brodbeck
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Laura Castelletti
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Aldo Feriani
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Iain Lingard
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Richard Myers
- Takeda Pharmaceuticals, 9625 Towne Centre Drive, San Diego, California 92121, United States
| | - Selena Nola
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Laura Piccoli
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Daniela Pompilio
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Luca F Raveglia
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Cristian Salvagno
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Sabrina Tassini
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Caterina Virginio
- Aptuit, an Evotec Company, Via Alessandro Fleming, 4, Verona 37135, Italy
| | - Mark Sabat
- Takeda Pharmaceuticals, 9625 Towne Centre Drive, San Diego, California 92121, United States
| |
Collapse
|
18
|
Nguyen QT, Beck Coburn GE, Valentino A, Karabucak B, Tizzano M. Mouse Mandibular Retromolar Taste Buds Associated With a Mucus Salivary Gland. Chem Senses 2021; 46:6226126. [PMID: 33855345 DOI: 10.1093/chemse/bjab019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have characterized a recently rediscovered chemosensory structure at the rear of the mandibular mucosa in the mouse oral cavity originally reported in the 1980s. This consists of unorganized taste buds, not contained within troughs, associated with the ducts of an underlying minor salivary gland. Using whole-mount preparations of transgenic mice expressing green fluorescent protein under the promoter of taste-signaling-specific genes, we determined that the structure contains taste bud clusters and salivary gland orifices at the rear of each mandible, distal to the last molar and anterior to the ascending ramus. Immunohistochemical analysis shows in the retromolar taste buds expression of the taste receptors Tas2R131 and T1R3 and taste cascade molecules TrpM5, PLCβ2, and GNAT3, consistent with type II taste cells, and expression of GAD1, consistent with type III taste cells. Furthermore, the neuronal marker, calcitonin gene-related peptide, in retromolar mucosa tissue wrapping around TrpM5+ taste buds was observed. RT-PCR showed that retromolar taste buds express all 3 mouse tas1r genes, 28 of the 35 tas2r genes, and taste transduction signaling genes gnat3, plcb2, and trpm5, making the retromolar taste buds similar to other lingual and palate taste buds. Finally, histochemistry demonstrated that the mandibular retromolar secretory gland is a minor salivary gland of mucous type. The mandibular retromolar taste structure may thus play a role in taste sensation and represent a potential novel pharmacological target for taste disorders.
Collapse
Affiliation(s)
- Quan T Nguyen
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Grace E Beck Coburn
- Department of Endodontics, The Robert Schattner Center, University of Pennsylvania, School of Dental Medicine, 240 South 40th Street, Philadelphia, PA 19104-6030, USA
| | - Amber Valentino
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Bekir Karabucak
- Department of Endodontics, The Robert Schattner Center, University of Pennsylvania, School of Dental Medicine, 240 South 40th Street, Philadelphia, PA 19104-6030, USA
| | - Marco Tizzano
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
- Department of Endodontics, The Robert Schattner Center, University of Pennsylvania, School of Dental Medicine, 240 South 40th Street, Philadelphia, PA 19104-6030, USA
| |
Collapse
|
19
|
Adhesion receptor ADGRG2/GPR64 is in the GI-tract selectively expressed in mature intestinal tuft cells. Mol Metab 2021; 51:101231. [PMID: 33831593 PMCID: PMC8105302 DOI: 10.1016/j.molmet.2021.101231] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/27/2021] [Accepted: 03/31/2021] [Indexed: 11/23/2022] Open
Abstract
Objective GPR64/ADGRG2 is an orphan Adhesion G protein-coupled receptor (ADGR) known to be mainly expressed in the parathyroid gland and epididymis. This investigation aimed to delineate the cellular expression of GPR64 throughout the body with focus on the gastrointestinal (GI) tract. Methods Transgenic Gpr64mCherry reporter mice were histologically examined throughout the body and reporter protein expression in intestinal tuft cells was confirmed by specific cell ablation. The GPCR repertoire of intestinal Gpr64mCherry-positive tuft cells was analyzed by quantitative RT-PCR analysis and in situ hybridization. The Gpr64mCherry was crossed into the general tuft cell reporter Trpm5GFP to generate small intestinal organoids for time-lapse imaging. Intestinal tuft cells were isolated from small intestine, FACS-purified and transcriptionally compared using RNA-seq analysis. Results Expression of the Gpr64mCherry reporter was identified in multiple organs and specifically in olfactory microvillous cells, enteric nerves, and importantly in respiratory and GI tuft cells. In the small intestine, cell ablation targeting Gpr64-expressing epithelial cells eliminated tuft cells. Transcriptional analysis of small intestinal Gpr64mCherry -positive tuft cells confirmed expression of Gpr64 and the chemo-sensors Sucnr1, Gprc5c, Drd3, and Gpr41/Ffar3. Time-lapse studies of organoids from Trpm5GFP:Gpr64mCherry mice revealed sequential expression of initially Trpm5GFP and subsequently also Gpr64mCherry in maturing intestinal tuft cells. RNA-seq analysis of small intestinal tuft cells based on these two markers demonstrated a dynamic change in expression of transcription factors and GPCRs from young to mature tuft cells. Conclusions GPR64 is expressed in chemosensory epithelial cells across a broad range of tissues; however, in the GI tract, GPR64 is remarkably selectively expressed in mature versus young immunoregulatory tuft cells. GPR64-RFP is expressed mainly in chemosensory epithelial cells, including tuft cells. Maturing intestinal tuft cells initially express Trpm5 and subsequently Gpr64. Mature intestinal Gpr64+ tuft cells express Sucnr1, Gprc5c, Drd3, and Gpr41/Ffar3. RNAseq analysis reveals dynamic transcriptional change of mature vs. young tuft cells.
Collapse
|
20
|
Dutta Banik D, Medler KF. Bitter, sweet, and umami signaling in taste cells: it’s not as simple as we thought. CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2021.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
21
|
Baxter BD, Larson ED, Merle L, Feinstein P, Polese AG, Bubak AN, Niemeyer CS, Hassell J, Shepherd D, Ramakrishnan VR, Nagel MA, Restrepo D. Transcriptional profiling reveals potential involvement of microvillous TRPM5-expressing cells in viral infection of the olfactory epithelium. BMC Genomics 2021; 22:224. [PMID: 33781205 PMCID: PMC8007386 DOI: 10.1186/s12864-021-07528-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 03/12/2021] [Indexed: 02/07/2023] Open
Abstract
Background Understanding viral infection of the olfactory epithelium is essential because the olfactory nerve is an important route of entry for viruses to the central nervous system. Specialized chemosensory epithelial cells that express the transient receptor potential cation channel subfamily M member 5 (TRPM5) are found throughout the airways and intestinal epithelium and are involved in responses to viral infection. Results Herein we performed deep transcriptional profiling of olfactory epithelial cells sorted by flow cytometry based on the expression of mCherry as a marker for olfactory sensory neurons and for eGFP in OMP-H2B::mCherry/TRPM5-eGFP transgenic mice (Mus musculus). We find profuse expression of transcripts involved in inflammation, immunity and viral infection in TRPM5-expressing microvillous cells compared to olfactory sensory neurons. Conclusion Our study provides new insights into a potential role for TRPM5-expressing microvillous cells in viral infection of the olfactory epithelium. We find that, as found for solitary chemosensory cells (SCCs) and brush cells in the airway epithelium, and for tuft cells in the intestine, the transcriptome of TRPM5-expressing microvillous cells indicates that they are likely involved in the inflammatory response elicited by viral infection of the olfactory epithelium. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07528-y.
Collapse
Affiliation(s)
- B Dnate' Baxter
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Eric D Larson
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Laetitia Merle
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Paul Feinstein
- The Graduate Center Biochemistry, Biology and CUNY-Neuroscience-Collaborative Programs and Biological Sciences Department, Hunter College, City University of New York, New York, NY, 10065, USA
| | - Arianna Gentile Polese
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Andrew N Bubak
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Christy S Niemeyer
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - James Hassell
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Doug Shepherd
- Department of Pharmacology, University of Colorado Anschutz Medical Campus and Center for Biological Physics and Department of Physics, Arizona State University, Tempe, USA
| | - Vijay R Ramakrishnan
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Maria A Nagel
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Diego Restrepo
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA. .,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
| |
Collapse
|
22
|
Ohman LC, Krimm RF. Whole-Mount Staining, Visualization, and Analysis of Fungiform, Circumvallate, and Palate Taste Buds. JOURNAL OF VISUALIZED EXPERIMENTS : JOVE 2021:10.3791/62126. [PMID: 33645587 PMCID: PMC8785251 DOI: 10.3791/62126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Taste buds are collections of taste-transducing cells specialized to detect subsets of chemical stimuli in the oral cavity. These transducing cells communicate with nerve fibers that carry this information to the brain. Because taste-transducing cells continuously die and are replaced throughout adulthood, the taste-bud environment is both complex and dynamic, requiring detailed analyses of its cell types, their locations, and any physical relationships between them. Detailed analyses have been limited by tongue-tissue heterogeneity and density that have significantly reduced antibody permeability. These obstacles require sectioning protocols that result in splitting taste buds across sections so that measurements are only approximated, and cell relationships are lost. To overcome these challenges, the methods described herein involve collecting, imaging, and analyzing whole taste buds and individual terminal arbors from three taste regions: fungiform papillae, circumvallate papillae, and the palate. Collecting whole taste buds reduces bias and technical variability and can be used to report absolute numbers for features including taste-bud volume, total taste-bud innervation, transducing-cell counts, and the morphology of individual terminal arbors. To demonstrate the advantages of this method, this paper provides comparisons of taste bud and innervation volumes between fungiform and circumvallate taste buds using a general taste-bud marker and a label for all taste fibers. A workflow for the use of sparse-cell genetic labeling of taste neurons (with labeled subsets of taste-transducing cells) is also provided. This workflow analyzes the structures of individual taste-nerve arbors, cell type numbers, and the physical relationships between cells using image analysis software. Together, these workflows provide a novel approach for tissue preparation and analysis of both whole taste buds and the complete morphology of their innervating arbors.
Collapse
Affiliation(s)
- Lisa C. Ohman
- Anatomical Sciences and Neurobiology, University of Louisville
| | - Robin F. Krimm
- Anatomical Sciences and Neurobiology, University of Louisville
| |
Collapse
|
23
|
Larson ED, Vandenbeuch A, Anderson CB, Kinnamon SC. GAD65Cre Drives Reporter Expression in Multiple Taste Cell Types. Chem Senses 2021; 46:bjab033. [PMID: 34160573 PMCID: PMC8276891 DOI: 10.1093/chemse/bjab033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In taste buds, Type I cells represent the majority of cells (50-60%) and primarily have a glial-like function in taste buds. However, recent studies suggest that they have additional sensory and signaling functions including amiloride-sensitive salt transduction, oxytocin modulation of taste, and substance P mediated GABA release. Nonetheless, the overall function of Type I cells in transduction and signaling remains unclear, primarily because of the lack of a reliable reporter for this cell type. GAD65 expression is specific to Type I taste cells and GAD65 has been used as a Cre driver to study Type I cells in salt taste transduction. To test the specificity of transgene-driven expression, we crossed GAD65Cre mice with floxed tdTomato and Channelrhodopsin (ChR2) lines and examined the progeny with immunochemistry, chorda tympani recording, and calcium imaging. We report that while many tdTomato+ taste cells express NTPDase2, a specific marker of Type I cells, we see some expression of tdTomato in both Gustducin and SNAP25-positive taste cells. We also see ChR2 in cells just outside the fungiform taste buds. Chorda tympani recordings in the GAD65Cre/ChR2 mice show large responses to blue light. Furthermore, several isolated tdTomato-positive taste cells responded to KCl depolarization with increases in intracellular calcium, indicating the presence of voltage-gated calcium channels. Taken together, these data suggest that GAD65Cre mice drive expression in multiple taste cell types and thus cannot be considered a reliable reporter of Type I cell function.
Collapse
Affiliation(s)
- Eric D Larson
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus and Rocky Mountain Taste and Smell Center, Aurora, CO, USA
| | - Aurelie Vandenbeuch
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus and Rocky Mountain Taste and Smell Center, Aurora, CO, USA
| | - Catherine B Anderson
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus and Rocky Mountain Taste and Smell Center, Aurora, CO, USA
| | - Sue C Kinnamon
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus and Rocky Mountain Taste and Smell Center, Aurora, CO, USA
| |
Collapse
|
24
|
Abstract
All organisms have the ability to detect chemicals in the environment, which likely evolved out of organisms' needs to detect food sources and avoid potentially harmful compounds. The taste system detects chemicals and is used to determine whether potential food items will be ingested or rejected. The sense of taste detects five known taste qualities: bitter, sweet, salty, sour, and umami, which is the detection of amino acids, specifically glutamate. These different taste qualities encompass a wide variety of chemicals that differ in their structure and as a result, the peripheral taste utilizes numerous and diverse mechanisms to detect these stimuli. In this chapter, we will summarize what is currently known about the signaling mechanisms used by taste cells to transduce stimulus signals.
Collapse
Affiliation(s)
- Debarghya Dutta Banik
- Department of Biological Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kathryn F Medler
- Department of Biological Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
25
|
Baxter BD, Larson ED, Merle L, Feinstein P, Polese AG, Bubak AN, Niemeyer CS, Hassell J, Shepherd D, Ramakrishnan VR, Nagel MA, Restrepo D. Transcriptional profiling reveals potential involvement of microvillous TRPM5-expressing cells in viral infection of the olfactory epithelium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511400 DOI: 10.1101/2020.05.14.096016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Understanding viral infection of the olfactory epithelium is essential because the olfactory nerve is an important route of entry for viruses to the central nervous system. Specialized chemosensory epithelial cells that express the transient receptor potential cation channel subfamily M member 5 (TRPM5) are found throughout the airways and intestinal epithelium and are involved in responses to viral infection. Results Herein we performed deep transcriptional profiling of olfactory epithelial cells sorted by flow cytometry based on the expression of mCherry as a marker for olfactory sensory neurons and for eGFP in OMP-H2B::mCherry/TRPM5-eGFP transgenic mice ( Mus musculus ). We find profuse expression of transcripts involved in inflammation, immunity and viral infection in TRPM5-expressing microvillous cells. Conclusion Our study provides new insights into a potential role for TRPM5-expressing microvillous cells in viral infection of the olfactory epithelium. We find that, as found for solitary chemosensory cells (SCCs) and brush cells in the airway epithelium, and for tuft cells in the intestine, the transcriptome of TRPM5-expressing microvillous cells indicates that they are likely involved in the inflammatory response elicited by viral infection of the olfactory epithelium.
Collapse
|
26
|
An alternative pathway for sweet sensation: possible mechanisms and physiological relevance. Pflugers Arch 2020; 472:1667-1691. [PMID: 33030576 DOI: 10.1007/s00424-020-02467-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/14/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
Sweet substances are detected by taste-bud cells upon binding to the sweet-taste receptor, a T1R2/T1R3 heterodimeric G protein-coupled receptor. In addition, experiments with mouse models lacking the sweet-taste receptor or its downstream signaling components led to the proposal of a parallel "alternative pathway" that may serve as metabolic sensor and energy regulator. Indeed, these mice showed residual nerve responses and behavioral attraction to sugars and oligosaccharides but not to artificial sweeteners. In analogy to pancreatic β cells, such alternative mechanism, to sense glucose in sweet-sensitive taste cells, might involve glucose transporters and KATP channels. Their activation may induce depolarization-dependent Ca2+ signals and release of GLP-1, which binds to its receptors on intragemmal nerve fibers. Via unknown neuronal and/or endocrine mechanisms, this pathway may contribute to both, behavioral attraction and/or induction of cephalic-phase insulin release upon oral sweet stimulation. Here, we critically review the evidence for a parallel sweet-sensitive pathway, involved signaling mechanisms, neural processing, interactions with endocrine hormonal mechanisms, and its sensitivity to different stimuli. Finally, we propose its physiological role in detecting the energy content of food and preparing for digestion.
Collapse
|
27
|
Dutta Banik D, Benfey ED, Martin LE, Kay KE, Loney GC, Nelson AR, Ahart ZC, Kemp BT, Kemp BR, Torregrossa AM, Medler KF. A subset of broadly responsive Type III taste cells contribute to the detection of bitter, sweet and umami stimuli. PLoS Genet 2020; 16:e1008925. [PMID: 32790785 PMCID: PMC7425866 DOI: 10.1371/journal.pgen.1008925] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/10/2020] [Indexed: 12/20/2022] Open
Abstract
Taste receptor cells use multiple signaling pathways to detect chemicals in potential food items. These cells are functionally grouped into different types: Type I cells act as support cells and have glial-like properties; Type II cells detect bitter, sweet, and umami taste stimuli; and Type III cells detect sour and salty stimuli. We have identified a new population of taste cells that are broadly tuned to multiple taste stimuli including bitter, sweet, sour, and umami. The goal of this study was to characterize these broadly responsive (BR) taste cells. We used an IP3R3-KO mouse (does not release calcium (Ca2+) from internal stores in Type II cells when stimulated with bitter, sweet, or umami stimuli) to characterize the BR cells without any potentially confounding input from Type II cells. Using live cell Ca2+ imaging in isolated taste cells from the IP3R3-KO mouse, we found that BR cells are a subset of Type III cells that respond to sour stimuli but also use a PLCβ signaling pathway to respond to bitter, sweet, and umami stimuli. Unlike Type II cells, individual BR cells are broadly tuned and respond to multiple stimuli across different taste modalities. Live cell imaging in a PLCβ3-KO mouse confirmed that BR cells use this signaling pathway to respond to bitter, sweet, and umami stimuli. Short term behavioral assays revealed that BR cells make significant contributions to taste driven behaviors and found that loss of either PLCβ3 in BR cells or IP3R3 in Type II cells caused similar behavioral deficits to bitter, sweet, and umami stimuli. Analysis of c-Fos activity in the nucleus of the solitary tract (NTS) also demonstrated that functional Type II and BR cells are required for normal stimulus induced expression. We use our taste system to decide if we are going to consume or reject a potential food item. This is critical for survival, as we need energy to live but also need to avoid potentially toxic compounds. Therefore, it is important to understand how the taste cells in our mouth detect the chemicals in food and send a message to our brain. Signals from the taste cells form a code that conveys information about the nature of the potential food item to the brain. How this taste coding works is not well understood. Currently, it is thought that taste cells are primarily selective for each taste stimuli and only detect either bitter, sweet, sour, salt, or umami (amino acids) compounds. Our study describes a new population of taste cells that can detect multiple types of stimuli, including chemicals from different taste qualities. Thus, taste cells can be either selective or generally responsive to stimuli which is similar to the cells in the brain that process taste information. The presence of these broadly responsive taste cells provides new insight into how taste information is sent to the brain for processing.
Collapse
Affiliation(s)
- Debarghya Dutta Banik
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Eric D. Benfey
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Laura E. Martin
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
| | - Kristen E. Kay
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
| | - Gregory C. Loney
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
| | - Amy R. Nelson
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Zachary C. Ahart
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Barrett T. Kemp
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Bailey R. Kemp
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
| | - Ann-Marie Torregrossa
- Department of Psychology, University at Buffalo, Buffalo, New York, United States of America
- Center for Ingestive Behavior Research, University at Buffalo, Buffalo, New York, United States of America
| | - Kathryn F. Medler
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, United States of America
- Center for Ingestive Behavior Research, University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
| |
Collapse
|
28
|
Nakao Y, Koshimura M, Yamasaki T, Ohtubo Y. Cell-type-independent expression of inwardly rectifying potassium currents in mouse fungiform taste bud cells. Physiol Res 2020; 69:501-510. [PMID: 32469236 DOI: 10.33549/physiolres.934331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Inwardly rectifying potassium (Kir) channels play key roles in functions, including maintaining the resting membrane potential and regulating the action potential duration in excitable cells. Using in situ whole-cell recordings, we investigated Kir currents in mouse fungiform taste bud cells (TBCs) and immunologically identified the cell types (type I-III) expressing these currents. We demonstrated that Kir currents occur in a cell-type-independent manner. The activation potentials we measured were -80 to -90 mV, and the magnitude of the currents increased as the membrane potentials decreased, irrespective of the cell types. The maximum current densities at -120 mV showed no significant differences among cell types (p>0.05, one-way ANOVA). The density of Kir currents was not correlated with the density of either transient inward currents or outwardly rectifying currents, although there was significant correlation between transient inward and outwardly rectifying current densities (p<0.05, test for no correlation). RT-PCR studies employing total RNA extracted from peeled lingual epithelia detected mRNAs for Kir1, Kir2, Kir4, Kir6, and Kir7 families. These findings indicate that TBCs express several types of Kir channels functionally, which may contribute to regulation of the resting membrane potential and signal transduction of taste.
Collapse
Affiliation(s)
- Y Nakao
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
| | | | | | | |
Collapse
|
29
|
Perniss A, Liu S, Boonen B, Keshavarz M, Ruppert AL, Timm T, Pfeil U, Soultanova A, Kusumakshi S, Delventhal L, Aydin Ö, Pyrski M, Deckmann K, Hain T, Schmidt N, Ewers C, Günther A, Lochnit G, Chubanov V, Gudermann T, Oberwinkler J, Klein J, Mikoshiba K, Leinders-Zufall T, Offermanns S, Schütz B, Boehm U, Zufall F, Bufe B, Kummer W. Chemosensory Cell-Derived Acetylcholine Drives Tracheal Mucociliary Clearance in Response to Virulence-Associated Formyl Peptides. Immunity 2020; 52:683-699.e11. [DOI: 10.1016/j.immuni.2020.03.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 12/25/2019] [Accepted: 03/13/2020] [Indexed: 12/24/2022]
|
30
|
Lemons K, Fu Z, Ogura T, Lin W. TRPM5-expressing Microvillous Cells Regulate Region-specific Cell Proliferation and Apoptosis During Chemical Exposure. Neuroscience 2020; 434:171-190. [PMID: 32224228 DOI: 10.1016/j.neuroscience.2020.03.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/23/2022]
Abstract
The mammalian main olfactory epithelium (MOE) is exposed to a wide spectrum of external chemicals during respiration and relies on adaptive plasticity to maintain its structural and functional integrity. We previously reported that the chemo-responsive and cholinergic transient receptor potential channel M5 (TRPM5)-expressing-microvillous cells (MCs) in the MOE are required for maintaining odor-evoked electrophysiological responses and olfactory-guided behavior during two-week exposure to an inhaled chemical mixture. Here, we investigated the underlying factors by assessing the potential modulatory effects of TRPM5-MCs on MOE morphology and cell proliferation and apoptosis, which are important for MOE maintenance. In the posterior MOE of TRPM5-GFP mice, we found that two-week chemical exposure induced a significant increase in Ki67-expressing proliferating basal stem cells without a significant reduction in the thickness of the whole epithelium or mature olfactory sensory neuron (OSN) layer. This adaptive increase in stem cell proliferation was missing in chemical-exposed transcription factor Skn-1a knockout (Skn-1a-/-) mice lacking TRPM5-MCs. In addition, a greater number of isolated OSNs from chemical-exposed Skn-1a-/- mice displayed unhealthily high levels of resting intracellular Ca2+. Intriguingly, in the anterior MOE where we found a higher density of TRPM5-MCs, chemical-exposed TRPM5-GFP mice exhibited a time-dependent increase in apoptosis and a loss of mature OSNs without a significant increase in proliferation or neurogenesis to compensate for OSN loss. Together, our data suggest that TRPM5-MC-dependent region-specific upregulation of cell proliferation in the majority of the MOE during chemical exposure contributes to the adaptive maintenance of OSNs and olfactory function.
Collapse
Affiliation(s)
- Kayla Lemons
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Ziying Fu
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA.
| |
Collapse
|
31
|
Sensing Senses: Optical Biosensors to Study Gustation. SENSORS 2020; 20:s20071811. [PMID: 32218129 PMCID: PMC7180777 DOI: 10.3390/s20071811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 12/11/2022]
Abstract
The five basic taste modalities, sweet, bitter, umami, salty and sour induce changes of Ca2+ levels, pH and/or membrane potential in taste cells of the tongue and/or in neurons that convey and decode gustatory signals to the brain. Optical biosensors, which can be either synthetic dyes or genetically encoded proteins whose fluorescence spectra depend on levels of Ca2+, pH or membrane potential, have been used in primary cells/tissues or in recombinant systems to study taste-related intra- and intercellular signaling mechanisms or to discover new ligands. Taste-evoked responses were measured by microscopy achieving high spatial and temporal resolution, while plate readers were employed for higher throughput screening. Here, these approaches making use of fluorescent optical biosensors to investigate specific taste-related questions or to screen new agonists/antagonists for the different taste modalities were reviewed systematically. Furthermore, in the context of recent developments in genetically encoded sensors, 3D cultures and imaging technologies, we propose new feasible approaches for studying taste physiology and for compound screening.
Collapse
|
32
|
von Molitor E, Nürnberg E, Ertongur-Fauth T, Scholz P, Riedel K, Hafner M, Rudolf R, Cesetti T. Analysis of calcium signaling in live human Tongue cell 3D-Cultures upon tastant perfusion. Cell Calcium 2020; 87:102164. [PMID: 32014795 DOI: 10.1016/j.ceca.2020.102164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/29/2019] [Accepted: 01/16/2020] [Indexed: 02/06/2023]
Abstract
Bridging the gap between two-dimensional cell cultures and complex in vivo tissues, three-dimensional cell culture models are of increasing interest in the fields of cell biology and pharmacology. However, present challenges hamper live cell imaging of three-dimensional cell cultures. These include (i) the stabilization of these structures under perfusion conditions, (ii) the recording of many z-planes at high spatio-temporal resolution, (iii) and the data analysis that ranges in complexity from whole specimens to single cells. Here, we addressed these issues for the time-lapse analysis of Ca2+ signaling in spheroids composed of human tongue-derived HTC-8 cells upon perfusion of gustatory substances. Live cell imaging setups for confocal and light sheet microscopy were developed that allow simple and robust spheroid stabilization and high-resolution microscopy with perfusion. Visualization of spheroids made of HTC-8 cells expressing the G-GECO fluorescent Ca2+ sensor revealed Ca2+ transients that showed similar kinetics but different amplitudes upon perfusion of bitter compounds Salicine and Saccharin. Dose-dependent responses to Saccharin required extracellular Ca2+. From the border towards the center of spheroids, compound-induced Ca2+ signals were progressively delayed and decreased in amplitude. Stimulation with ATP led to strong Ca2+ transients that were faster than those evoked by the bitter compounds and blockade of purinergic receptors with Suramin abutted the response to Saccharin, suggesting that ATP mediates a positive autocrine and paracrine feedback. Imaging of ATP-induced Ca2+ transients with light sheet microscopy allowed acquisition over a z-depth of 100 μm without losing spatial and temporal resolution. In summary, the presented approaches permit the study of fast cellular signaling in three-dimensional cultures upon compound perfusion.
Collapse
Affiliation(s)
- Elena von Molitor
- Institute of Molecular and Cell Biology, Hochschule Mannheim, 68163 Mannheim, Germany
| | - Elina Nürnberg
- Institute of Molecular and Cell Biology, Hochschule Mannheim, 68163 Mannheim, Germany
| | | | | | | | - Mathias Hafner
- Institute of Molecular and Cell Biology, Hochschule Mannheim, 68163 Mannheim, Germany.
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Hochschule Mannheim, 68163 Mannheim, Germany; Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany.
| | - Tiziana Cesetti
- Institute of Molecular and Cell Biology, Hochschule Mannheim, 68163 Mannheim, Germany
| |
Collapse
|
33
|
Huang AY. Immune Responses Alter Taste Perceptions: Immunomodulatory Drugs Shape Taste Signals during Treatments. J Pharmacol Exp Ther 2019; 371:684-691. [PMID: 31611237 DOI: 10.1124/jpet.119.261297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/08/2019] [Indexed: 01/01/2023] Open
Abstract
Considering that nutrients are required in health and diseases, the detection and ingestion of food to meet the requirements is attributable to the sense of taste. Altered taste sensations lead to a decreased appetite, which is usually one of the frequent causes of malnutrition in patients with diseases. Ongoing taste research has identified a variety of drug pathways that cause changes in taste perceptions in cancer, increasing our understanding of taste disturbances attributable to aberrant mechanisms of taste sensation. The evidence discussed in this review, which addresses the implications of innate immune responses in the modulation of taste functions, focuses on the adverse effects on taste transmission from taste buds by immune modulators responsible for alterations in the perceived intensity of some taste modalities. Another factor, damage to taste progenitor cells that directly results in local effects on taste buds, must also be considered in relation to taste disturbances in patients with cancer. Recent discoveries discussed have provided new insights into the pathophysiology of taste dysfunctions associated with the specific treatments. SIGNIFICANCE STATEMENT: The paradigm that taste signals transmitted to the brain are determined only by tastant-mediated activation via taste receptors has been challenged by the immune modification of taste transmission through drugs during the processing of gustatory information in taste buds. This article reports the findings in a model system (mouse taste buds) that explain the basis for the taste dysfunctions in patients with cancer that has long been observed but never understood.
Collapse
Affiliation(s)
- Anthony Y Huang
- Department of Anatomy and Center for Integrated Research in Cognitive and Neural Science, Southern Illinois University School of Medicine, Carbondale, Illinois
| |
Collapse
|
34
|
Zheng X, Tizzano M, Redding K, He J, Peng X, Jiang P, Xu X, Zhou X, Margolskee RF. Gingival solitary chemosensory cells are immune sentinels for periodontitis. Nat Commun 2019; 10:4496. [PMID: 31582750 PMCID: PMC6776549 DOI: 10.1038/s41467-019-12505-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 09/13/2019] [Indexed: 02/05/2023] Open
Abstract
Solitary chemosensory cells (SCCs) are epithelial sentinels that utilize bitter Tas2r receptors and coupled taste transduction elements to detect pathogenic bacterial metabolites, triggering host defenses to control the infection. Here we report that SCCs are present in mouse gingival junctional epithelium, where they express several Tas2rs and the taste signaling components α-gustducin (Gnat3), TrpM5, and Plcβ2. Gnat3-/- mice have altered commensal oral microbiota and accelerated naturally occurring alveolar bone loss. In ligature-induced periodontitis, knockout of taste signaling molecules or genetic absence of gingival SCCs (gSCCs) increases the bacterial load, reduces bacterial diversity, and renders the microbiota more pathogenic, leading to greater alveolar bone loss. Topical treatment with bitter denatonium to activate gSCCs upregulates the expression of antimicrobial peptides and ameliorates ligature-induced periodontitis in wild-type but not in Gnat3-/- mice. We conclude that gSCCs may provide a promising target for treating periodontitis by harnessing innate immunity to regulate the oral microbiome.
Collapse
Affiliation(s)
- Xin Zheng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Marco Tizzano
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Kevin Redding
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Jinzhi He
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China
| | - Xian Peng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, PA, 19104, USA
| | - Xin Xu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China.
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China.
| | | |
Collapse
|
35
|
Cellular and Neural Responses to Sour Stimuli Require the Proton Channel Otop1. Curr Biol 2019; 29:3647-3656.e5. [PMID: 31543453 DOI: 10.1016/j.cub.2019.08.077] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/08/2019] [Accepted: 08/30/2019] [Indexed: 11/24/2022]
Abstract
The sense of taste allows animals to sample chemicals in the environment prior to ingestion. Of the five basic tastes, sour, the taste of acids, had remained among the most mysterious. Acids are detected by type III taste receptor cells (TRCs), located in taste buds across the tongue and palate epithelium. The first step in sour taste transduction is believed to be entry of protons into the cell cytosol, which leads to cytosolic acidification and the generation of action potentials. The proton-selective ion channel Otop1 is expressed in type III TRCs and is a candidate sour receptor. Here, we tested the contribution of Otop1 to taste cell and gustatory nerve responses to acids in mice in which Otop1 was genetically inactivated (Otop1-KO mice). We first show that Otop1 is required for the inward proton current in type III TRCs from different parts of the tongue that are otherwise molecularly heterogeneous. We next show that in type III TRCs from Otop1-KO mice, intracellular pH does not track with extracellular pH and that moderately acidic stimuli do not elicit trains of action potentials, as they do in type III TRCs from wild-type mice. Moreover, gustatory nerve responses in Otop1-KO mice were severely and selectively attenuated for acidic stimuli, including citric acid and HCl. These results establish that the Otop1 proton channel plays a critical role in acid detection in the mouse gustatory system, evidence that it is a bona fide sour taste receptor.
Collapse
|
36
|
Rane CK, Jackson SR, Pastore CF, Zhao G, Weiner AI, Patel NN, Herbert DR, Cohen NA, Vaughan AE. Development of solitary chemosensory cells in the distal lung after severe influenza injury. Am J Physiol Lung Cell Mol Physiol 2019; 316:L1141-L1149. [PMID: 30908939 PMCID: PMC6620670 DOI: 10.1152/ajplung.00032.2019] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 12/24/2022] Open
Abstract
H1N1 influenza virus infection induces dramatic and permanent alveolar remodeling mediated by p63+ progenitor cell expansion in both mice and some patients with acute respiratory distress syndrome. This persistent lung epithelial dysplasia is accompanied by chronic inflammation, but the driver(s) of this pathology are unknown. This work identified de novo appearance of solitary chemosensory cells (SCCs), as defined by the tuft cell marker doublecortin-like kinase 1, in post-influenza lungs, arising in close proximity with the dysplastic epithelium, whereas uninjured lungs are devoid of SCCs. Interestingly, fate mapping demonstrated that these cells are derived from p63-expressing lineage-negative progenitors, the same cell of origin as the dysplastic epithelium. Direct activation of SCCs with denatonium + succinate increased plasma extravasation specifically in post-influenza virus-injured lungs. Thus we demonstrate the previously unrecognized development and activity of SCCs in the lung following influenza virus infection, implicating SCCs as a central feature of dysplastic remodeling.
Collapse
Affiliation(s)
- Chetan K Rane
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Sergio R Jackson
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Christopher F Pastore
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Gan Zhao
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Aaron I Weiner
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Neil N Patel
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - De'Broski R Herbert
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Noam A Cohen
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
- Monell Chemical Senses Center , Philadelphia, Pennsylvania
- Philadelphia Veterans Affairs Medical Center Surgical Service , Philadelphia, Pennsylvania
| | - Andrew E Vaughan
- School of Veterinary Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
- Institute for Regenerative Medicine, University of Pennsylvania , Philadelphia, Pennsylvania
| |
Collapse
|
37
|
Transient receptor potential vanilloid 4 mediates sour taste sensing via type III taste cell differentiation. Sci Rep 2019; 9:6686. [PMID: 31040368 PMCID: PMC6491610 DOI: 10.1038/s41598-019-43254-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 04/16/2019] [Indexed: 12/31/2022] Open
Abstract
Taste buds are comprised of taste cells, which are classified into types I to IV. Transient receptor potential (TRP) channels play a significant role in taste perception. TRP vanilloid 4 (TRPV4) is a non-selective cation channel that responds to mechanical, thermal, and chemical stimuli. The present study aimed to define the function and expression of TRPV4 in taste buds using Trpv4-deficient mice. In circumvallate papillae, TRPV4 colocalized with a type IV cell and epithelial cell marker but not type I, II, or III markers. Behavioural studies showed that Trpv4 deficiency reduced sensitivity to sourness but not to sweet, umami, salty, and bitter tastes. Trpv4 deficiency significantly reduced the expression of type III cells compared with that in wild type (WT) mice in vivo and in taste bud organoid experiments. Trpv4 deficiency also significantly reduced Ki67-positive cells and β-catenin expression compared with those in WT circumvallate papillae. Together, the present results suggest that TRPV4 contributes to sour taste sensing by regulating type III taste cell differentiation in mice.
Collapse
|
38
|
Xu J, Lewandowski BC, Miyazawa T, Shoji Y, Yee K, Bryant BP. Spilanthol Enhances Sensitivity to Sodium in Mouse Taste Bud Cells. Chem Senses 2019; 44:91-103. [PMID: 30364996 PMCID: PMC6350677 DOI: 10.1093/chemse/bjy069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Overconsumption of NaCl has been linked to increased hypertension-related morbidity. Compounds that can enhance NaCl responses in taste cells could help reduce human NaCl consumption without sacrificing perceived saltiness. Spilanthol is an unsaturated alkylamide isolated from the Jambu plant (Acmella oleracea) that can induce tingling, pungency, and numbing in the mouth. Structurally similar fatty acid amides, such as sanshool, elicit numbing and tingling sensations by inhibiting 2-pore-domain potassium leak channels on trigeminal sensory neurons. Even when insufficient to induce action potential firing, leak current inhibition causes depolarization and increased membrane resistance, which combine to make cells more sensitive to subsequent depolarizing stimuli, such as NaCl. Using calcium imaging, we tested whether spilanthol alters sensitivity to NaCl in isolated circumvallate taste bud cells and trigeminal sensory neurons of mice (Mus musculus). Micromolar spilanthol elicited little to no response in taste bud cells or trigeminal neurons. These same perithreshold concentrations of spilanthol significantly enhanced responses to NaCl (140 and 200 mM) in taste bud cells. Trigeminal neurons, however, exhibited response enhancement only at the highest concentrations of NaCl and spilanthol tested. Using a combination of potassium depolarization, immunohistochemistry, and Trpm5-GFP and Tas1r3-GFP mice to characterize taste bud cells by type, we found spilanthol enhancement of NaCl responses most prevalent in NaCl-responsive type III cells, and commonly observed in NaCl-responsive type II cells. Our results indicate that spilanthol enhances NaCl responses in taste bud cells and point to a family of compounds that may have utility as salty taste enhancers.
Collapse
Affiliation(s)
- Jiang Xu
- Monell Chemical Senses Center, Philadelphia, PA , USA
| | | | | | - Yasutaka Shoji
- Ogawa & Co. Ltd., Nihonbashi Honcho Chuo-ku, Tokyo, Japan
| | - Karen Yee
- Monell Chemical Senses Center, Philadelphia, PA , USA
| | | |
Collapse
|
39
|
Abstract
The study of taste has been guided throughout much of its history by the conceptual framework of psychophysics, where the focus was on quantification of the subjective experience of the taste sensations. By the mid-20th century, data from physiologic studies had accumulated sufficiently to assemble a model for the function of receptors that must mediate the initial stimulus of tastant molecules in contact with the tongue. But the study of taste as a receptor-mediated event did not gain momentum until decades later when the actual receptor proteins and attendant signaling mechanisms were identified and localized to the highly specialized taste-responsive cells of the tongue. With those discoveries a new opportunity to examine taste as a function of receptor activity has come into focus. Pharmacology is the science designed specifically for the experimental interrogation and quantitative characterization of receptor function at all levels of inquiry from molecules to behavior. This review covers the history of some of the major concepts that have shaped thinking and experimental approaches to taste, the seminal discoveries that have led to elucidation of receptors for taste, and how applying principles of receptor pharmacology can enhance understanding of the mechanisms of taste physiology and perception.
Collapse
Affiliation(s)
- R Kyle Palmer
- Opertech Bio, Inc., Pennovation Center, Philadelphia, Pennsylvania
| |
Collapse
|
40
|
Pan HR, Tian M, Xue JB, Li SM, Luo XC, Huang X, Chen ZH, Huang L. Mammalian Taste Bud Cells Utilize Extragemmal 5-Hydroxy-L-Tryptophan to Biosynthesize the Neurotransmitter Serotonin. Front Cell Neurosci 2018; 12:461. [PMID: 30534058 PMCID: PMC6275321 DOI: 10.3389/fncel.2018.00461] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/12/2018] [Indexed: 01/31/2023] Open
Abstract
Serotonin or 5-hydroxytryptamine (5-HT) is an important neurotransmitter that is found in mammalian taste buds and can regulate the output of intragemmal signaling networks onto afferent nerve fibers. However, it is unclear how 5-HT is produced, synthesized locally inside taste buds or absorbed from outside sources. In this study, we attempt to address this question by delineating the process of possible 5-HT biosynthesis within taste buds. First, we verified that the rate-limiting enzyme tryptophan hydroxylase (TPH2) responsible for converting L-tryptophan into the intermediate 5-hydroxy-L-tryptophan (5-HTP) is expressed in a subset of type II taste bud cells (TBCs) whereas the enzyme aromatic L-aromatic amino acid decarboxylase (AADC) capable of converting 5-HTP into 5-HT is found in type III TBCs. And abolishment of TPH2 did not affect the production of intragemmal 5-HT or alter TBCs; the mutant mice did not show any changes in behavioral responses to all five primary taste qualities: sweet, umami, bitter, salty, and sour. Then we identified that 5-HTP as well as AADC are abundant in type III TBCs; and application of an AADC inhibitor significantly blocked the production of 5-HT in taste buds. In contrast, administration of an inhibitor on serotonin-reuptake transporters had minimal impact on the 5-HT amount in taste buds, indicating that exogenous 5-HT is not a major source for the intragemmal transmitter. Taken together, our data indicate that intragemmal serotonin is not biosynthesized de novo from tryptophan; instead, it is produced by AADC-mediated conversion of 5-HTP absorbed from the plasma and/or nerve fibers into 5-HT. Thus, our results suggest that the overall bodily 5-HTP level in the plasma and nervous system can regulate taste buds' physiological function, and provide an important molecular mechanism connecting these peripheral taste organs with the circulatory and nervous systems.
Collapse
Affiliation(s)
- Hong-Ru Pan
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Miao Tian
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jian-Bo Xue
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Song-Min Li
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xiao-Cui Luo
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xiao Huang
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhen-Huang Chen
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Liquan Huang
- Institute of Cellular and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou, China
- Monell Chemical Senses Center, Philadelphia, PA, United States
| |
Collapse
|
41
|
O'Leary CE, Schneider C, Locksley RM. Tuft Cells-Systemically Dispersed Sensory Epithelia Integrating Immune and Neural Circuitry. Annu Rev Immunol 2018; 37:47-72. [PMID: 30379593 DOI: 10.1146/annurev-immunol-042718-041505] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Tuft cells-rare solitary chemosensory cells in mucosal epithelia-are undergoing intense scientific scrutiny fueled by recent discovery of unsuspected connections to type 2 immunity. These cells constitute a conduit by which ligands from the external space are sensed via taste-like signaling pathways to generate outputs unique among epithelial cells: the cytokine IL-25, eicosanoids associated with allergic immunity, and the neurotransmitter acetylcholine. The classic type II taste cell transcription factor POU2F3 is lineage defining, suggesting a conceptualization of these cells as widely distributed environmental sensors with effector functions interfacing type 2 immunity and neural circuits. Increasingly refined single-cell analytics have revealed diversity among tuft cells that extends from nasal epithelia and type II taste cells to ex-Aire-expressing medullary thymic cells and small-intestine cells that mediate tissue remodeling in response to colonizing helminths and protists.
Collapse
Affiliation(s)
- Claire E O'Leary
- Department of Medicine, University of California, San Francisco, California 94143, USA; , ,
| | - Christoph Schneider
- Department of Medicine, University of California, San Francisco, California 94143, USA; , ,
| | - Richard M Locksley
- Department of Medicine, University of California, San Francisco, California 94143, USA; , , .,Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA.,University of California, San Francisco, Howard Hughes Medical Institute, San Francisco, California 94143, USA
| |
Collapse
|
42
|
AlMatrouk A, Lemons K, Ogura T, Luo W, Wilson C, Lin W. Chemical Exposure-Induced Changes in the Expression of Neurotrophins and Their Receptors in the Main Olfactory System of Mice Lacking TRPM5-Expressing Microvillous Cells. Int J Mol Sci 2018; 19:E2939. [PMID: 30261693 PMCID: PMC6213160 DOI: 10.3390/ijms19102939] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/25/2018] [Accepted: 09/24/2018] [Indexed: 12/27/2022] Open
Abstract
Functional maintenance of the mammalian main olfactory epithelium (MOE) is challenging because of its direct exposure to a wide spectrum of environmental chemicals. We previously reported that transient receptor potential channel M5-expressing microvillous cells (TRPM5-MCs) in the MOE play an important role in olfactory maintenance. To investigate the underpinning mechanisms, we exposed transcription factor Skn-1a knockout (Skn-1a-/-) mice lacking TRPM5-MCs, and TRPM5-GFP mice to either vehicle (water) or a mixture of odorous chemicals and chitin for two weeks and analyzed the expression of olfactory signaling proteins using immunolabeling and neurotrophin (NT) and NT receptor (NTR) gene transcripts using real-time quantitative PCR. The chemical exposure did not significantly attenuate the immunolabeling of olfactory signaling proteins. Vehicle-exposed Skn-1a-/- and TRPM5-GFP mice expressed similar levels of NT and NTR gene transcripts in the MOE and olfactory bulb. Chemical exposure significantly increased MOE expression of p75NTR in Skn-1a-/- mice, while p75NTR expression was reduced in TRPM5-GFP mice, as compared to vehicle-exposed mice. Additionally, our RNA in situ hybridization analysis and immunolabeling confirmed MOE expression of most NTs and NTRs. Together, these results indicate that TRPM5-MCs and chemical exposure influence expression of some NTs and NTRs in the MOE and olfactory bulb (OB).
Collapse
Affiliation(s)
- Abdullah AlMatrouk
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Kayla Lemons
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Wangmei Luo
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Chantel Wilson
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| |
Collapse
|
43
|
Genovese F, Tizzano M. Microvillous cells in the olfactory epithelium express elements of the solitary chemosensory cell transduction signaling cascade. PLoS One 2018; 13:e0202754. [PMID: 30212469 PMCID: PMC6136699 DOI: 10.1371/journal.pone.0202754] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 08/08/2018] [Indexed: 11/18/2022] Open
Abstract
The nasal cavity hosts an array of chemoresponsive cells, including the extended olfactory system and several other cells involved in detection of and responses to irritants. Solitary chemosensory cells (SCCs), which respond to irritants and bacteria, express the transient receptor potential channel TRPM5 an essential element of the taste transduction-signaling cascade. Microvillous cells (MVCs), non-neuronal cells situated in the apical layer of the main olfactory epithelium, also express TRPM5, but their function has not yet been clarified. TRPM5-positive MVCs, like SCCs, show a cholinergic phenotype expressing choline acetyl transferase (ChAT), but none of the other elements of the bitter taste transduction cascade could be detected. We reexamined TRPM5-positive MVCs with more sensitive gene expression and staining techniques to clarify whether they rely only on TRPM5 and ChAT or express other elements of the taste/SCC transduction cascade. Analyzing existing RNA sequencing data from whole olfactory mucosa and isolated olfactory sensory neurons, we determined that several elements of the taste/SCC transduction cascade, including taste receptors, are expressed in the olfactory mucosa in cells other than olfactory sensory neurons. Immunostaining confirmed the presence TRPM5 and ChAT in a subset of cells of the olfactory mucosa, which also showed the expression of PLCB2, gustducin, and T1R3. Specifically, these cells were identified as TRPM5-positive MVCs. Furthermore, we examined whether MVCs are innervated by trigeminal fibers, similarly to SCCs. Using antibodies against trigeminal nerve markers calcitonin gene-related peptide and substance P, we determined that, despite the cholinergic phenotype, most MVCs in the olfactory mucosa lacked consistent trigeminal innervation. Our findings indicate that MVCs, like SCCs, express all the elements of the bitter taste transduction cascade but that, unlike SCCs, they possess only sparse trigeminal innervation. The cholinergic phenotype of MVCs suggests a modulatory function of the surrounding olfactory epithelium, through the release of acetylcholine.
Collapse
Affiliation(s)
- Federica Genovese
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Marco Tizzano
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| |
Collapse
|
44
|
López-Gambero AJ, Martínez F, Salazar K, Cifuentes M, Nualart F. Brain Glucose-Sensing Mechanism and Energy Homeostasis. Mol Neurobiol 2018; 56:769-796. [PMID: 29796992 DOI: 10.1007/s12035-018-1099-4] [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: 01/30/2018] [Accepted: 04/25/2018] [Indexed: 01/02/2023]
Abstract
The metabolic and energy state of the organism depends largely on the availability of substrates, such as glucose for ATP production, necessary for maintaining physiological functions. Deregulation in glucose levels leads to the appearance of pathological signs that result in failures in the cardiovascular system and various diseases, such as diabetes, obesity, nephropathy, and neuropathy. Particularly, the brain relies on glucose as fuel for the normal development of neuronal activity. Regions adjacent to the cerebral ventricles, such as the hypothalamus and brainstem, exercise central control in energy homeostasis. These centers house nuclei of neurons whose excitatory activity is sensitive to changes in glucose levels. Determining the different detection mechanisms, the phenotype of neurosecretion, and neural connections involving glucose-sensitive neurons is essential to understanding the response to hypoglycemia through modulation of food intake, thermogenesis, and activation of sympathetic and parasympathetic branches, inducing glucagon and epinephrine secretion and other hypothalamic-pituitary axis-dependent counterregulatory hormones, such as glucocorticoids and growth hormone. The aim of this review focuses on integrating the current understanding of various glucose-sensing mechanisms described in the brain, thereby establishing a relationship between neuroanatomy and control of physiological processes involved in both metabolic and energy balance. This will advance the understanding of increasingly prevalent diseases in the modern world, especially diabetes, and emphasize patterns that regulate and stimulate intake, thermogenesis, and the overall synergistic effect of the neuroendocrine system.
Collapse
Affiliation(s)
- A J López-Gambero
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile.,Department of Cell Biology, Genetics and Physiology, University of Malaga, IBIMA, BIONAND, Andalusian Center for Nanomedicine and Biotechnology and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, Málaga, Spain
| | - F Martínez
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
| | - K Salazar
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile
| | - M Cifuentes
- Department of Cell Biology, Genetics and Physiology, University of Malaga, IBIMA, BIONAND, Andalusian Center for Nanomedicine and Biotechnology and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine, Málaga, Spain.
| | - F Nualart
- Laboratory of Neurobiology and Stem Cells NeuroCellT, Department of Cellular Biology, Center for Advanced Microscopy CMA BIO BIO, Faculty of Biological Sciences, University of Concepcion, Concepcion, Chile. .,Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
| |
Collapse
|
45
|
Romanov RA, Lasher RS, High B, Savidge LE, Lawson A, Rogachevskaja OA, Zhao H, Rogachevsky VV, Bystrova MF, Churbanov GD, Adameyko I, Harkany T, Yang R, Kidd GJ, Marambaud P, Kinnamon JC, Kolesnikov SS, Finger TE. Chemical synapses without synaptic vesicles: Purinergic neurotransmission through a CALHM1 channel-mitochondrial signaling complex. Sci Signal 2018; 11:11/529/eaao1815. [PMID: 29739879 DOI: 10.1126/scisignal.aao1815] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Conventional chemical synapses in the nervous system involve a presynaptic accumulation of neurotransmitter-containing vesicles, which fuse with the plasma membrane to release neurotransmitters that activate postsynaptic receptors. In taste buds, type II receptor cells do not have conventional synaptic features but nonetheless show regulated release of their afferent neurotransmitter, ATP, through a large-pore, voltage-gated channel, CALHM1. Immunohistochemistry revealed that CALHM1 was localized to points of contact between the receptor cells and sensory nerve fibers. Ultrastructural and super-resolution light microscopy showed that the CALHM1 channels were consistently associated with distinctive, large (1- to 2-μm) mitochondria spaced 20 to 40 nm from the presynaptic membrane. Pharmacological disruption of the mitochondrial respiratory chain limited the ability of taste cells to release ATP, suggesting that the immediate source of released ATP was the mitochondrion rather than a cytoplasmic pool of ATP. These large mitochondria may serve as both a reservoir of releasable ATP and the site of synthesis. The juxtaposition of the large mitochondria to areas of membrane displaying CALHM1 also defines a restricted compartment that limits the influx of Ca2+ upon opening of the nonselective CALHM1 channels. These findings reveal a distinctive organelle signature and functional organization for regulated, focal release of purinergic signals in the absence of synaptic vesicles.
Collapse
Affiliation(s)
- Roman A Romanov
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow Region 142290, Russia.,Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria.,Immanuel Kant Baltic Federal University, Kaliningrad 236041, Russia
| | - Robert S Lasher
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University Colorado School of Medicine, Aurora, CO 80045, USA
| | - Brigit High
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University Colorado School of Medicine, Aurora, CO 80045, USA
| | - Logan E Savidge
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University Colorado School of Medicine, Aurora, CO 80045, USA
| | - Adam Lawson
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University Colorado School of Medicine, Aurora, CO 80045, USA
| | - Olga A Rogachevskaja
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow Region 142290, Russia
| | - Haitian Zhao
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, Manhasset, NY 11030, USA
| | - Vadim V Rogachevsky
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow Region 142290, Russia.,United Pushchino Center for Electron Microscopy, Pushchino, Moscow Region 142290, Russia
| | - Marina F Bystrova
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow Region 142290, Russia
| | - Gleb D Churbanov
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow Region 142290, Russia
| | - Igor Adameyko
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria.,Department of Physiology and Pharmacology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria.,Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Ruibiao Yang
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University Colorado School of Medicine, Aurora, CO 80045, USA
| | - Grahame J Kidd
- Department of Neuroscience, Lerner Research Institute, Cleveland Clinic, and 3D-Electron Microscopy, Renovo Neural Inc., Cleveland, OH 44195, USA
| | - Philippe Marambaud
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, Manhasset, NY 11030, USA
| | - John C Kinnamon
- Rocky Mountain Taste and Smell Center, Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Stanislav S Kolesnikov
- Institute of Cell Biophysics, Russian Academy of Science, Pushchino, Moscow Region 142290, Russia.
| | - Thomas E Finger
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, University Colorado School of Medicine, Aurora, CO 80045, USA.
| |
Collapse
|
46
|
CALHM3 Is Essential for Rapid Ion Channel-Mediated Purinergic Neurotransmission of GPCR-Mediated Tastes. Neuron 2018; 98:547-561.e10. [PMID: 29681531 DOI: 10.1016/j.neuron.2018.03.043] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 02/26/2018] [Accepted: 03/26/2018] [Indexed: 11/21/2022]
Abstract
Binding of sweet, umami, and bitter tastants to G protein-coupled receptors (GPCRs) in apical membranes of type II taste bud cells (TBCs) triggers action potentials that activate a voltage-gated nonselective ion channel to release ATP to gustatory nerves mediating taste perception. Although calcium homeostasis modulator 1 (CALHM1) is necessary for ATP release, the molecular identification of the channel complex that provides the conductive ATP-release mechanism suitable for action potential-dependent neurotransmission remains to be determined. Here we show that CALHM3 interacts with CALHM1 as a pore-forming subunit in a CALHM1/CALHM3 hexameric channel, endowing it with fast voltage-activated gating identical to that of the ATP-release channel in vivo. Calhm3 is co-expressed with Calhm1 exclusively in type II TBCs, and its genetic deletion abolishes taste-evoked ATP release from taste buds and GPCR-mediated taste perception. Thus, CALHM3, together with CALHM1, is essential to form the fast voltage-gated ATP-release channel in type II TBCs required for GPCR-mediated tastes.
Collapse
|
47
|
Fu Z, Ogura T, Luo W, Lin W. ATP and Odor Mixture Activate TRPM5-Expressing Microvillous Cells and Potentially Induce Acetylcholine Release to Enhance Supporting Cell Endocytosis in Mouse Main Olfactory Epithelium. Front Cell Neurosci 2018; 12:71. [PMID: 29615870 PMCID: PMC5869921 DOI: 10.3389/fncel.2018.00071] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
The main olfactory epithelium (MOE) functions to detect odor molecules, provide an epithelial surface barrier, and remove xenobiotics from inhaled air. Mechanisms coordinating the activities of different cell types within the MOE to maintain these functions are poorly understood. Previously, we showed that superficially located microvillous cells (MCs) in the MOE expressing transient receptor potential channel M5 (TRPM5) are cholinergic and chemoresponsive and that they play an important role in maintaining odor responses and olfactory-guided behavior under challenging chemical environment. Here we investigated TRPM5-MC activation and subsequent paracrine regulation. Ca2+ imaging showed that TRPM5-MCs dose-dependently increase their intracellular Ca2+ levels in response to ATP, an important signaling molecule for airway mucociliary movement, and to an odor mixture. Pharmacological examination showed that the ATP responses are primarily mediated by P2X purinergic receptors. Interestingly, using the endocytosis dye pHrodo Red dextran, we found that chemical-activated TRPM5-MCs significantly increase the number of pHrodo-labeled puncta compared to controls without stimulation and compared to cells that do not respond to ATP or to the odor mixture. These results indicate potential vesicle recycling after release of the signaling molecule acetylcholine (ACh). Interestingly, TRPM5 knockout (KO) results in a decrease in ATP-induced pHrodo internalization. We further investigated cholinergic regulation of neighboring supporting cells (SCs). We found that ACh strongly elevates intracellular Ca2+ and potentiates pHrodo endocytosis in SCs. The ACh effects are diminished in the presence of atropine or M3 muscarinic receptor antagonist and in SCs lacking M3 receptors. Collectively, these data suggest that TRPM5-MCs may regulate the MOE’s multicellular network activity via cholinergic paracrine signaling for functional maintenance and adaptive plasticity.
Collapse
Affiliation(s)
- Ziying Fu
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Wangmei Luo
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, United States
| |
Collapse
|
48
|
Yuan Z, Ma J, Meng X, Chen N, Shen M. Chk2 deficiency alleviates irradiation-induced taste dysfunction by inhibiting p53-dependent apoptosis. Oral Dis 2018; 24:856-863. [PMID: 29292572 DOI: 10.1111/odi.12822] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 12/15/2017] [Accepted: 12/21/2017] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Taste dysfunction is one of the most common complications following radiotherapy, which leads to decreased appetite and life quality of patients suffering from head and neck cancer. The aim of this study was to investigate the role of checkpoint kinase 2 (Chk2) deficiency in irradiation-induced taste dysfunction. MATERIALS AND METHODS Alterations in oxidative stress, DNA damage, and potential signaling pathway were compared between Chk2-deficient (Chk2-/- ) mice and their wild-type (WT) littermates pre-irradiation and 7 and 30 days postirradiation by biochemistry and immunohistochemistry. RESULTS Chk2-/- mice showed less loss of type II and type III taste cells, lower expression of p53, caspase-3, and cleaved caspase-3, and lower apoptosis levels. However, no significant differences in H2 O2 and MDA concentrations, T-SOD and GSH-Px activities, and expression of SOD1, SOD2, and 8-OHdG were detected in the taste buds of Chk2-/- mice as compared to those of WT mice. CONCLUSION Chk2 deficiency downregulated the expression of p53 and inhibited cellular apoptosis, partly contributing to the radioprotective effect on taste cells, but did not alter oxidative stress levels, antioxidant ability, and oxidative DNA damage in taste buds.
Collapse
Affiliation(s)
- Zhiyao Yuan
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Junchi Ma
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Xin Meng
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Ning Chen
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China
| | - Ming Shen
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.,Department of Dental Implant, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China
| |
Collapse
|
49
|
Qin Y, Sukumaran SK, Jyotaki M, Redding K, Jiang P, Margolskee RF. Gli3 is a negative regulator of Tas1r3-expressing taste cells. PLoS Genet 2018; 14:e1007058. [PMID: 29415007 PMCID: PMC5819828 DOI: 10.1371/journal.pgen.1007058] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 02/20/2018] [Accepted: 10/08/2017] [Indexed: 12/25/2022] Open
Abstract
Mouse taste receptor cells survive from 3-24 days, necessitating their regeneration throughout adulthood. In anterior tongue, sonic hedgehog (SHH), released by a subpopulation of basal taste cells, regulates transcription factors Gli2 and Gli3 in stem cells to control taste cell regeneration. Using single-cell RNA-Seq we found that Gli3 is highly expressed in Tas1r3-expressing taste receptor cells and Lgr5+ taste stem cells in posterior tongue. By PCR and immunohistochemistry we found that Gli3 was expressed in taste buds in all taste fields. Conditional knockout mice lacking Gli3 in the posterior tongue (Gli3CKO) had larger taste buds containing more taste cells than did control wild-type (Gli3WT) mice. In comparison to wild-type mice, Gli3CKO mice had more Lgr5+ and Tas1r3+ cells, but fewer type III cells. Similar changes were observed ex vivo in Gli3CKO taste organoids cultured from Lgr5+ taste stem cells. Further, the expression of several taste marker and Gli3 target genes was altered in Gli3CKO mice and/or organoids. Mirroring these changes, Gli3CKO mice had increased lick responses to sweet and umami stimuli, decreased lick responses to bitter and sour taste stimuli, and increased glossopharyngeal taste nerve responses to sweet and bitter compounds. Our results indicate that Gli3 is a suppressor of stem cell proliferation that affects the number and function of mature taste cells, especially Tas1r3+ cells, in adult posterior tongue. Our findings shed light on the role of the Shh pathway in adult taste cell regeneration and may help devise strategies for treating taste distortions from chemotherapy and aging.
Collapse
Affiliation(s)
- Yumei Qin
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
- School of Food Science and Biotechnology, Zhejiang Gonshang University, Hangzhou, Zhejiang, China
| | - Sunil K. Sukumaran
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Masafumi Jyotaki
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Kevin Redding
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| | - Robert F. Margolskee
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, United States of America
| |
Collapse
|
50
|
Tu YH, Cooper AJ, Teng B, Chang RB, Artiga DJ, Turner HN, Mulhall EM, Ye W, Smith AD, Liman ER. An evolutionarily conserved gene family encodes proton-selective ion channels. Science 2018; 359:1047-1050. [PMID: 29371428 DOI: 10.1126/science.aao3264] [Citation(s) in RCA: 155] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022]
Abstract
Ion channels form the basis for cellular electrical signaling. Despite the scores of genetically identified ion channels selective for other monatomic ions, only one type of proton-selective ion channel has been found in eukaryotic cells. By comparative transcriptome analysis of mouse taste receptor cells, we identified Otopetrin1 (OTOP1), a protein required for development of gravity-sensing otoconia in the vestibular system, as forming a proton-selective ion channel. We found that murine OTOP1 is enriched in acid-detecting taste receptor cells and is required for their zinc-sensitive proton conductance. Two related murine genes, Otop2 and Otop3, and a Drosophila ortholog also encode proton channels. Evolutionary conservation of the gene family and its widespread tissue distribution suggest a broad role for proton channels in physiology and pathophysiology.
Collapse
Affiliation(s)
- Yu-Hsiang Tu
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Alexander J Cooper
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Bochuan Teng
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Rui B Chang
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Daniel J Artiga
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Heather N Turner
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Eric M Mulhall
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Wenlei Ye
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Andrew D Smith
- Department of Biological Sciences, Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA. .,Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| |
Collapse
|