1
|
Oike A, Iwata S, Hirayama A, Ono Y, Nagasato Y, Kawabata Y, Takai S, Sanematsu K, Wada N, Shigemura N. Bisphosphonate affects the behavioral responses to HCl by disrupting farnesyl diphosphate synthase in mouse taste bud and tongue epithelial cells. Sci Rep 2022; 12:21246. [PMID: 36481783 PMCID: PMC9732047 DOI: 10.1038/s41598-022-25755-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Little is known about the molecular mechanisms underlying drug-induced taste disorders, which can cause malnutrition and reduce quality of life. One of taste disorders is known adverse effects of bisphosphonates, which are administered as anti-osteoporotic drugs. Therefore, the present study evaluated the effects of risedronate (a bisphosphonate) on taste bud cells. Expression analyses revealed that farnesyl diphosphate synthase (FDPS, a key enzyme in the mevalonate pathway) was present in a subset of mouse taste bud and tongue epithelial cells, especially type III sour-sensitive taste cells. Other mevalonate pathway-associated molecules were also detected in mouse taste buds. Behavioral analyses revealed that mice administered risedronate exhibited a significantly enhanced aversion to HCl but not for other basic taste solutions, whereas the taste nerve responses were not affected by risedronate. Additionally, the taste buds of mice administered risedronate exhibited significantly lower mRNA expression of desmoglein-2, an integral component of desmosomes. Taken together, these findings suggest that risedronate may interact directly with FDPS to inhibit the mevalonate pathway in taste bud and tongue epithelial cells, thereby affecting the expression of desmoglein-2 related with epithelial barrier function, which may lead to alterations in behavioral responses to HCl via somatosensory nerves.
Collapse
Affiliation(s)
- Asami Oike
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan ,grid.177174.30000 0001 2242 4849Section of Interdisciplinary Dentistry, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Shusuke Iwata
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan ,grid.177174.30000 0001 2242 4849Research and Development Center for Five-Sense Devices, Kyushu University, Fukuoka, Japan
| | - Ayaka Hirayama
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yurika Ono
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yuki Nagasato
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yuko Kawabata
- grid.177174.30000 0001 2242 4849Department of Cell Biology, Aging Science, and Pharmacology, Division of Oral Biological Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Shingo Takai
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Keisuke Sanematsu
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan ,grid.177174.30000 0001 2242 4849Research and Development Center for Five-Sense Devices, Kyushu University, Fukuoka, Japan ,grid.177174.30000 0001 2242 4849Oral Health/Brain Health/Total Health Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Naohisa Wada
- grid.177174.30000 0001 2242 4849Section of Interdisciplinary Dentistry, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
| | - Noriatsu Shigemura
- grid.177174.30000 0001 2242 4849Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan ,grid.177174.30000 0001 2242 4849Research and Development Center for Five-Sense Devices, Kyushu University, Fukuoka, Japan
| |
Collapse
|
2
|
Berselli A, Benfenati F, Maragliano L, Alberini G. Multiscale modelling of claudin-based assemblies: a magnifying glass for novel structures of biological interfaces. Comput Struct Biotechnol J 2022; 20:5984-6010. [DOI: 10.1016/j.csbj.2022.10.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/03/2022] Open
|
3
|
Kozieł MJ, Ziaja M, Piastowska-Ciesielska AW. Intestinal Barrier, Claudins and Mycotoxins. Toxins (Basel) 2021; 13:758. [PMID: 34822542 PMCID: PMC8622050 DOI: 10.3390/toxins13110758] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 02/08/2023] Open
Abstract
The intestinal barrier is the main barrier against all of the substances that enter the body. Proper functioning of this barrier guarantees maintained balance in the organism. Mycotoxins are toxic, secondary fungi metabolites, that have a negative impact both on human and animal health. It was postulated that various mycotoxins may affect homeostasis by disturbing the intestinal barrier. Claudins are proteins that are involved in creating tight junctions between epithelial cells. A growing body of evidence underlines their role in molecular response to mycotoxin-induced cytotoxicity. This review summarizes the information connected with claudins, their association with an intestinal barrier, physiological conditions in general, and with gastrointestinal cancers. Moreover, this review also includes information about the changes in claudin expression upon exposition to various mycotoxins.
Collapse
|
4
|
Golden EJ, Larson ED, Shechtman LA, Trahan GD, Gaillard D, Fellin TJ, Scott JK, Jones KL, Barlow LA. Onset of taste bud cell renewal starts at birth and coincides with a shift in SHH function. eLife 2021; 10:64013. [PMID: 34009125 PMCID: PMC8172241 DOI: 10.7554/elife.64013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 05/18/2021] [Indexed: 12/12/2022] Open
Abstract
Embryonic taste bud primordia are specified as taste placodes on the tongue surface and differentiate into the first taste receptor cells (TRCs) at birth. Throughout adult life, TRCs are continually regenerated from epithelial progenitors. Sonic hedgehog (SHH) signaling regulates TRC development and renewal, repressing taste fate embryonically, but promoting TRC differentiation in adults. Here, using mouse models, we show TRC renewal initiates at birth and coincides with onset of SHHs pro-taste function. Using transcriptional profiling to explore molecular regulators of renewal, we identified Foxa1 and Foxa2 as potential SHH target genes in lingual progenitors at birth and show that SHH overexpression in vivo alters FoxA1 and FoxA2 expression relevant to taste buds. We further bioinformatically identify genes relevant to cell adhesion and cell locomotion likely regulated by FOXA1;FOXA2 and show that expression of these candidates is also altered by forced SHH expression. We present a new model where SHH promotes TRC differentiation by regulating changes in epithelial cell adhesion and migration.
Collapse
Affiliation(s)
- Erin J Golden
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States.,The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Eric D Larson
- The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States.,Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Lauren A Shechtman
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States.,The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - G Devon Trahan
- Department of Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplant, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Dany Gaillard
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States.,The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Timothy J Fellin
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States.,The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Jennifer K Scott
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States.,The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Kenneth L Jones
- Department of Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplant, University of Colorado Anschutz Medical Campus, Aurora, United States
| | - Linda A Barlow
- Department of Cell & Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, United States.,The Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, United States
| |
Collapse
|
5
|
Imafuku K, Kamaguchi M, Natsuga K, Nakamura H, Shimizu H, Iwata H. Zonula occludens-1 demonstrates a unique appearance in buccal mucosa over several layers. Cell Tissue Res 2021; 384:691-702. [PMID: 33635425 DOI: 10.1007/s00441-021-03425-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/24/2021] [Indexed: 02/07/2023]
Abstract
Tight junctions (TJs) firmly seal epithelial cells and are key players in the epithelial barrier. TJs consist of several proteins, including those of the transmembrane claudin family and the scaffold zonula occludens (ZO) family. Epithelial tissues are exposed to different conditions: to air in the stratified epithelium of the skin and to liquids in the monolayer of the intestine. The TJs in stratified oral mucosal epithelium have remained insufficiently elucidated in terms of distributions, appearances and barrier functions of TJ proteins in normal buccal mucosa. We investigated these and ZO-1 and claudin-1 were found to be expressed in the top third and in the bottom three quarters of the mucosal epithelium. ZO-1 in the buccal mucosa was found to have an irregular linear appearance. ZO-1 in the buccal mucosa continuously existed in several layers. Electron microscopy revealed the buccal mucosa to have kissing points. In a biotin permeation assay that sought to investigate inside-outside barrier function, the biotin tracer penetrated several ZO-1 layers but did not pass through all the ZO-1 layers. We found that the oral mucosal cell knockdown of TJP1 or CLDN1 resulted in decreases of TER but no significant change in FITC-dextran leakage. Our results suggest that the distribution and appearance of ZO-1 in the buccal mucosa differ from those in the skin. We were unable to prove barrier function in this study but we did show barrier function against small molecules in vivo and against ions in vitro.
Collapse
Affiliation(s)
- Keisuke Imafuku
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Mayumi Kamaguchi
- Department of Oral Diagnosis and Medicine, Faculty of Medicine and Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo, 060-8586, Japan.,Lübeck Institute of Experimental Dermatology, University of Lübeck, Building B9 Ratzeburger Allee 160, 23562, Lubeck, Germany
| | - Ken Natsuga
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Hideki Nakamura
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Hiroshi Shimizu
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan
| | - Hiroaki Iwata
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-ku, 060-8638, Sapporo, Japan.
| |
Collapse
|
6
|
Roper SD. Chemical and electrical synaptic interactions among taste bud cells. CURRENT OPINION IN PHYSIOLOGY 2021; 20:118-125. [PMID: 33521414 DOI: 10.1016/j.cophys.2020.12.004] [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] [Indexed: 10/22/2022]
Abstract
Chemical synapses between taste cells were first proposed based on electron microscopy of fish taste buds. Subsequently, researchers found considerable evidence for electrical coupling in fish, amphibian, and possibly mammalian taste buds. The development lingual slice and isolated cell preparations allowed detailed investigations of cell-cell interactions, both chemical and electrical, in taste buds. The identification of serotonin and ATP as taste neurotransmitters focused attention onto chemical synaptic interactions between taste cells and research on electrical coupling faded. Findings from Ca2+ imaging, electrophysiology, and molecular biology indicate that several neurotransmitters, including ATP, serotonin, GABA, acetylcholine, and norepinephrine, are secreted by taste cells and exert paracrine interactions in taste buds. Most work has been done on interactions between Type II and Type III taste cells. This brief review follows the trail of studies on cell-cell interactions in taste buds, from the initial ultrastructural observations to the most recent optogenetic manipulations.
Collapse
Affiliation(s)
- Stephen D Roper
- Department of Physiology & Biophysics and Department of Otolaryngology, Miller School of Medicine, University of Miami, FL 33136
| |
Collapse
|
7
|
Ikuta R, Myoenzono K, Wasano J, Hamaguchi-Hamada K, Hamada S, Kurumata-Shigeto M. N-cadherin localization in taste buds of mouse circumvallate papillae. J Comp Neurol 2020; 529:2227-2242. [PMID: 33319419 DOI: 10.1002/cne.25090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 01/03/2023]
Abstract
Taste buds, the receptor organs for taste, contain 50-100 taste bud cells. Although these cells undergo continuous turnover, the structural and functional integrity of taste buds is maintained. The molecular mechanisms by which synaptic connectivity between taste buds and afferent fibers is formed and maintained remain ambiguous. In the present study, we examined the localization of N-cadherin in the taste buds of the mouse circumvallate papillae because N-cadherin, one of the classical cadherins, is important for the formation and maintenance of synapses. At the light microscopic level, N-cadherin was predominantly detected in type II cells and nerve fibers in the connective tissues in and around the vallate papillae. At the ultrastructural level, N-cadherin immunoreactivity appears along the cell membrane and in the intracellular vesicles of type II cells. N-cadherin immunoreactivity also is evident in the membranes of afferent terminals at the contact sites to N-cadherin-positive type II cells. At channel type synapses between type II cells and nerve fibers, N-cadherin is present surrounding, but not within, the presumed neurotransmitter release zone, identified by large mitochondria apposed to the taste cells. The present results suggest that N-cadherin is important for the formation or maintenance of type II cell afferent synapses in taste buds.
Collapse
Affiliation(s)
- Rio Ikuta
- International College of Arts and Sciences, Fukuoka Women's University, Fukuoka, Japan
| | - Kanae Myoenzono
- International College of Arts and Sciences, Fukuoka Women's University, Fukuoka, Japan.,Humanome Lab., Inc., Tokyo, Japan
| | - Jun Wasano
- International College of Arts and Sciences, Fukuoka Women's University, Fukuoka, Japan
| | | | - Shun Hamada
- International College of Arts and Sciences, Fukuoka Women's University, Fukuoka, Japan
| | - Mami Kurumata-Shigeto
- International College of Arts and Sciences, Fukuoka Women's University, Fukuoka, Japan
| |
Collapse
|
8
|
Abstract
How taste buds detect NaCl remains poorly understood. Among other problems, applying taste-relevant concentrations of NaCl (50-500 mm) onto isolated taste buds or cells exposes them to unphysiological (hypo/hypertonic) conditions. To overcome these limitations, we used the anterior tongue of male and female mice to implement a slice preparation in which fungiform taste buds are in a relatively intact tissue environment and stimuli are limited to the taste pore. Taste-evoked responses were monitored using confocal Ca2+ imaging via GCaMP3 expressed in Type 2 and Type 3 taste bud cells. NaCl evoked intracellular mobilization of Ca2+ in the apical tips of a subset of taste cells. The concentration dependence and rapid adaptation of NaCl-evoked cellular responses closely resembled behavioral and afferent nerve responses to NaCl. Importantly, taste cell responses were not inhibited by the diuretic, amiloride. Post hoc immunostaining revealed that >80% of NaCl-responsive taste bud cells were of Type 2. Many NaCl-responsive cells were also sensitive to stimuli that activate Type 2 cells but never to stimuli for Type 3 cells. Ion substitutions revealed that amiloride-insensitive NaCl responses depended on Cl- rather than Na+ Moreover, choline chloride, an established salt taste enhancer, was equally effective a stimulus as sodium chloride. Although the apical transducer for Cl- remains unknown, blocking known chloride channels and cotransporters had little effect on NaCl responses. Together, our data suggest that chloride, an essential nutrient, is a key determinant of taste transduction for amiloride-insensitive salt taste.SIGNIFICANCE STATEMENT Sodium and chloride are essential nutrients and must be regularly consumed to replace excreted NaCl. Thus, understanding salt taste, which informs salt appetite, is important from a fundamental sensory perspective and forms the basis for interventions to replace/reduce excess Na+ consumption. This study examines responses to NaCl in a semi-intact preparation of mouse taste buds. We identify taste cells that respond to NaCl in the presence of amiloride, which is significant because much of human salt taste also is amiloride-insensitive. Further, we demonstrate that Cl-, not Na+, generates these amiloride-insensitive salt taste responses. Intriguingly, choline chloride, a commercial salt taste enhancer, is also a highly effective stimulus for these cells.
Collapse
|
9
|
Roebber JK, Roper SD, Chaudhari N. The Role of the Anion in Salt (NaCl) Detection by Mouse Taste Buds. J Neurosci 2019; 39:6224-6232. [PMID: 31171579 PMCID: PMC6687907 DOI: 10.1523/jneurosci.2367-18.2019] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 05/14/2019] [Accepted: 05/24/2019] [Indexed: 11/21/2022] Open
Abstract
How taste buds detect NaCl remains poorly understood. Among other problems, applying taste-relevant concentrations of NaCl (50-500 mm) onto isolated taste buds or cells exposes them to unphysiological (hypo/hypertonic) conditions. To overcome these limitations, we used the anterior tongue of male and female mice to implement a slice preparation in which fungiform taste buds are in a relatively intact tissue environment and stimuli are limited to the taste pore. Taste-evoked responses were monitored using confocal Ca2+ imaging via GCaMP3 expressed in Type 2 and Type 3 taste bud cells. NaCl evoked intracellular mobilization of Ca2+ in the apical tips of a subset of taste cells. The concentration dependence and rapid adaptation of NaCl-evoked cellular responses closely resembled behavioral and afferent nerve responses to NaCl. Importantly, taste cell responses were not inhibited by the diuretic, amiloride. Post hoc immunostaining revealed that >80% of NaCl-responsive taste bud cells were of Type 2. Many NaCl-responsive cells were also sensitive to stimuli that activate Type 2 cells but never to stimuli for Type 3 cells. Ion substitutions revealed that amiloride-insensitive NaCl responses depended on Cl- rather than Na+ Moreover, choline chloride, an established salt taste enhancer, was equally effective a stimulus as sodium chloride. Although the apical transducer for Cl- remains unknown, blocking known chloride channels and cotransporters had little effect on NaCl responses. Together, our data suggest that chloride, an essential nutrient, is a key determinant of taste transduction for amiloride-insensitive salt taste.SIGNIFICANCE STATEMENT Sodium and chloride are essential nutrients and must be regularly consumed to replace excreted NaCl. Thus, understanding salt taste, which informs salt appetite, is important from a fundamental sensory perspective and forms the basis for interventions to replace/reduce excess Na+ consumption. This study examines responses to NaCl in a semi-intact preparation of mouse taste buds. We identify taste cells that respond to NaCl in the presence of amiloride, which is significant because much of human salt taste also is amiloride-insensitive. Further, we demonstrate that Cl-, not Na+, generates these amiloride-insensitive salt taste responses. Intriguingly, choline chloride, a commercial salt taste enhancer, is also a highly effective stimulus for these cells.
Collapse
Affiliation(s)
| | - Stephen D Roper
- Program in Neurosciences
- Department of Physiology and Biophysics, and
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Nirupa Chaudhari
- Program in Neurosciences,
- Department of Physiology and Biophysics, and
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida 33136
| |
Collapse
|
10
|
Takahashi Y, Takahashi H, Stern PL, Kirita T, Tsuboi A. Expression of Oncofetal Antigen 5T4 in Murine Taste Papillae. Front Cell Neurosci 2019; 13:343. [PMID: 31417363 PMCID: PMC6685444 DOI: 10.3389/fncel.2019.00343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/12/2019] [Indexed: 12/26/2022] Open
Abstract
Background: Multicellular taste buds located within taste papillae on the tongue mediate taste sensation. In taste papillae, taste bud cells (TBCs), such as taste receptor cells and taste precursor cells, and the surrounding lingual epithelium including epithelial progenitors (also called taste stem/progenitor cells) are maintained by continuous cell turnover throughout life. However, it remains unknown how the cells constituting taste buds proliferate and differentiate to maintain taste bud tissue. Based on in situ hybridization (ISH) screening, we demonstrated that the oncofetal antigen 5T4 (also known as trophoblast glycoprotein: TPBG) gene is expressed in the adult mouse tongue. Results: In immunohistochemistry of coronal tongue sections, 5T4 protein was detected at a low level exclusively in the basal part of the lingual epithelium in developing and adult mice, and at a high level particularly in foliate papillae and circumvallate papillae (CVPs). Furthermore, immunohistochemistry of the basal part of CVPs indicated that the proliferation marker PCNA (proliferating cell nuclear antigen) co-localized with 5T4. 5T4 was strongly expressed in Krt5+ epithelial progenitors and Shh+ taste precursor cells, but weakly in mature taste receptor cells. The number of proliferating cells in the CVP was higher in 5T4-knockout mice than in wild-type (WT) mice, while neither cell differentiation nor the size of taste buds differed between these two groups of mice. Notably, X-ray irradiation enhanced cell proliferation more in 5T4-knockout mice than in WT mice. Conclusion: Our results suggest that 5T4, expressed in epithelial progenitors (taste stem/progenitor cells), and taste precursor cells, may influence the maintenance of taste papillae under both normal and injury conditions.
Collapse
Affiliation(s)
- Yuka Takahashi
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara, Japan
| | - Hiroo Takahashi
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara, Japan
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Miki-cho, Japan
| | - Peter L. Stern
- Division of Molecular and Clinical Cancer Sciences, University of Manchester, Manchester, United Kingdom
| | - Tadaaki Kirita
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara, Japan
| | - Akio Tsuboi
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Kashihara, Japan
- Laboratory for Cellular and Molecular Neurobiology, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| |
Collapse
|
11
|
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
|
12
|
Stolle T, Grondinger F, Dunkel A, Meng C, Médard G, Kuster B, Hofmann T. Salivary Proteome Patterns Affecting Human Salt Taste Sensitivity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:9275-9286. [PMID: 28981267 DOI: 10.1021/acs.jafc.7b03862] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To investigate the role of perireceptor events in inter-individual variability in salt taste sensitivity, 31 volunteers were monitored in their detection functions for sodium chloride (NaCl) and classified into sensitive (0.6-1.7 mmol/L), medium-sensitive (1.8-6.9 mmol/L), and nonsensitive (7.0-11.2 mmol/L) subjects. Chemosensory intervention of NaCl-sensitive (S+) and nonsensitive (S-) panellists with potassium chloride, ammonium chloride, and sodium gluconate showed the salt taste sensitivity to be specific for NaCl. As no significant differences were found between S+ and S- subjects in salivary sodium and protein content, salivary proteome differences and their stimulus-induced dynamic changes were analyzed by tryptic digestion, iTRAQ labeling, and liquid chromatography-tandem mass spectrometry analysis. Differences in the salivary proteome between S+ and S- subjects were found primarily in resting saliva and were largely independent of the dynamic alterations observed upon salt stimulation. Gene ontology enrichment analysis of key proteins, i.e., immunoglobulin heavy constant y1, myeloblastin, cathepsin G, and kallikrein, revealed significantly increased serine-type endopeptidase activity for the S+ group, while the S- group exhibited augmented cysteine-type endopeptidase inhibitor activity by increased abundances in lipocalin-1 and cystatin-D, -S, and -SN, respectively. As proteases have been suggested to facilitate transepithelial sodium transport by cleaving the y-subunit of the epithelial sodium channel (ENaC) and protease inhibitors have been shown to reduce ENaC-mediated sodium transport, the differentially modulated proteolytic activity patterns observed in vivo for S+ and S- subjects show evidence of them playing a crucial role in affecting human NaCl sensitivity.
Collapse
Affiliation(s)
- Theresa Stolle
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich , Lise-Meitner Strasse 34, D-85354 Freising, Germany
| | - Freya Grondinger
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich , Lise-Meitner Strasse 34, D-85354 Freising, Germany
| | - Andreas Dunkel
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich , Lise-Meitner Strasse 34, D-85354 Freising, Germany
| | - Chen Meng
- Chair of Proteomics and Bioanalytics, Technical University of Munich , Emil-Erlenmeyer-Forum 5, D-85354 Freising, Germany
| | - Guillaume Médard
- Chair of Proteomics and Bioanalytics, Technical University of Munich , Emil-Erlenmeyer-Forum 5, D-85354 Freising, Germany
| | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technical University of Munich , Emil-Erlenmeyer-Forum 5, D-85354 Freising, Germany
| | - Thomas Hofmann
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich , Lise-Meitner Strasse 34, D-85354 Freising, Germany
| |
Collapse
|
13
|
Inhibition of TGF-β signaling supports high proliferative potential of diverse p63 + mouse epithelial progenitor cells in vitro. Sci Rep 2017; 7:6089. [PMID: 28729719 PMCID: PMC5519764 DOI: 10.1038/s41598-017-06470-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 06/13/2017] [Indexed: 12/21/2022] Open
Abstract
Mouse models have been used to provide primary cells to study physiology and pathogenesis of epithelia. However, highly efficient simple approaches to propagate mouse primary epithelial cells remain challenging. Here, we show that pharmacological inhibition of TGF-β signaling enables long-term expansion of p63+ epithelial progenitor cells in low Ca2+ media without the need of progenitor cell-purification steps or support by a feeder cell layer. We find that TGF-β signaling is operative in mouse primary keratinocytes in conventional cultures as determined by the nuclear Smad2/3 localization. Accordingly, TGF-β signaling inhibition in crude preparations of mouse epidermis robustly increases proliferative capacity of p63+ epidermal progenitor cells, while preserving their ability of differentiation in response to Ca2+ stimulation. Notably, inhibition of TGF-β signaling also enriches and expands other p63+ epithelial progenitor cells in primary crude cultures of multiple epithelia, including the cornea, oral and lingual epithelia, salivary gland, esophagus, thymus, and bladder. We anticipate that this simple and efficient approach will facilitate the use of mouse models for studying a wide range of epithelia by providing highly enriched populations of diverse p63+ epithelial progenitor cells in quantity.
Collapse
|
14
|
Cell fate specification in the lingual epithelium is controlled by antagonistic activities of Sonic hedgehog and retinoic acid. PLoS Genet 2017; 13:e1006914. [PMID: 28715412 PMCID: PMC5536368 DOI: 10.1371/journal.pgen.1006914] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/31/2017] [Accepted: 07/09/2017] [Indexed: 12/20/2022] Open
Abstract
The interaction between signaling pathways is a central question in the study of organogenesis. Using the developing murine tongue as a model, we uncovered unknown relationships between Sonic hedgehog (SHH) and retinoic acid (RA) signaling. Genetic loss of SHH signaling leads to enhanced RA activity subsequent to loss of SHH-dependent expression of Cyp26a1 and Cyp26c1. This causes a cell identity switch, prompting the epithelium of the tongue to form heterotopic minor salivary glands and to overproduce oversized taste buds. At developmental stages during which Wnt10b expression normally ceases and Shh becomes confined to taste bud cells, loss of SHH inputs causes the lingual epithelium to undergo an ectopic and anachronic expression of Shh and Wnt10b in the basal layer, specifying de novo taste placode induction. Surprisingly, in the absence of SHH signaling, lingual epithelial cells adopted a Merkel cell fate, but this was not caused by enhanced RA signaling. We show that RA promotes, whereas SHH, acting strictly within the lingual epithelium, inhibits taste placode and lingual gland formation by thwarting RA activity. These findings reveal key functions for SHH and RA in cell fate specification in the lingual epithelium and aid in deciphering the molecular mechanisms that assign cell identity. Knowledge of the biological mechanisms controlling cell fate specification is of paramount importance for cell-based therapies. Sonic hedgehog (SHH) and retinoic acid (RA) pathways play key roles in development and disease. The role of SHH during in vivo tongue development is a subject of great interest, and whether RA signaling has any function in the developing tongue is unknown. The tongue is covered by a mucosa made of lingual epithelium and lingual mesenchyme. Various structures, including mechanosensory filiform papillae, gustatory papillae harboring taste buds, and minor salivary glands, arise from the epithelium, but how these entities are specified remains unclear. Here we show that in the mesenchyme SHH signaling drives growth and morphogenesis, whereas in the epithelium, SHH controls patterning and cell fate specification. We demonstrate that SHH inhibits taste placode and lingual gland formation by antagonizing RA inputs. We also show that loss of SHH signaling elicits Merkel cell formation in the lingual epithelium, a tissue normally bereft of Merkel cells. This is at odds with the hairy epidermis where Merkel cell specification has been shown to be SHH-dependent. Our study establishes SHH and RA as key players in the control of cell identity within the lingual epithelium.
Collapse
|
15
|
Abstract
The past decade has witnessed a consolidation and refinement of the extraordinary progress made in taste research. This Review describes recent advances in our understanding of taste receptors, taste buds, and the connections between taste buds and sensory afferent fibres. The article discusses new findings regarding the cellular mechanisms for detecting tastes, new data on the transmitters involved in taste processing and new studies that address longstanding arguments about taste coding.
Collapse
|
16
|
Bardag-Gorce F, Hoft RH, Wood A, Oliva J, Niihara H, Makalinao A, Thropay J, Pan D, Meepe I, Tiger K, Garcia J, Laporte A, French SW, Niihara Y. The Role of E-Cadherin in Maintaining the Barrier Function of Corneal Epithelium after Treatment with Cultured Autologous Oral Mucosa Epithelial Cell Sheet Grafts for Limbal Stem Deficiency. J Ophthalmol 2016; 2016:4805986. [PMID: 27777792 PMCID: PMC5061954 DOI: 10.1155/2016/4805986] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/29/2016] [Accepted: 08/01/2016] [Indexed: 11/17/2022] Open
Abstract
The role of E-cadherin in epithelial barrier function of cultured autologous oral mucosa epithelial cell sheet (CAOMECS) grafts was examined. CAOMECS were cultured on a temperature-responsive surface and grafted onto rabbit corneas with Limbal Stem Cell Deficiency (LSCD). E-cadherin levels were significantly higher in CAOMECS compared to normal and LSCD epithelium. Beta-catenin colocalized with E-cadherin in CAOMECS cell membranes while phosphorylated beta-catenin was significantly increased. ZO-1, occludin, and Cnx43 were also strongly expressed in CAOMECS. E-cadherin and beta-catenin localization at the cell membrane was reduced in LSCD corneas, while CAOMECS-grafted corneas showed a restoration of E-cadherin and beta-catenin expression. LSCD corneas did not show continuous staining for ZO-1 or for Cnx43, while CAOMECS-grafted corneas showed a positive expression of ZO-1 and Cnx43. Cascade Blue® hydrazide did not pass through CAOMECS. Because E-cadherin interactions are calcium-dependent, EGTA was used to chelate calcium and disrupt cell adhesion. EGTA-treated CAOMECS completely detached from cell culture surface, and E-cadherin levels were significantly decreased. In conclusion, E cadherin high expression contributed to CAOMECS tight and gap junction protein recruitment at the cell membrane, thus promoting cellular adhesion and a functional barrier to protect the ocular surface.
Collapse
Affiliation(s)
- Fawzia Bardag-Gorce
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Richard H. Hoft
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Andrew Wood
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Joan Oliva
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Hope Niihara
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Andrew Makalinao
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Jacquelyn Thropay
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Derek Pan
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Imara Meepe
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Kumar Tiger
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Julio Garcia
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Amanda Laporte
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Samuel W. French
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| | - Yutaka Niihara
- Los Angeles Biomedical Research Institute (LA BioMed), Harbor UCLA Medical Center, Torrance, CA 90502, USA
| |
Collapse
|
17
|
Baker OJ. Current trends in salivary gland tight junctions. Tissue Barriers 2016; 4:e1162348. [PMID: 27583188 DOI: 10.1080/21688370.2016.1162348] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 02/28/2016] [Accepted: 03/01/2016] [Indexed: 12/21/2022] Open
Abstract
Tight junctions form a continuous intercellular barrier between epithelial cells that is required to separate tissue spaces and regulate selective movement of solutes across the epithelium. They are composed of strands containing integral membrane proteins (e.g., claudins, occludin and tricellulin, junctional adhesion molecules and the coxsackie adenovirus receptor). These proteins are anchored to the cytoskeleton via scaffolding proteins such as ZO-1 and ZO-2. In salivary glands, tight junctions are involved in polarized saliva secretion and barrier maintenance between the extracellular environment and the glandular lumen. This review seeks to provide an overview of what is currently known, as well as the major questions and future research directions, regarding tight junction expression, organization and function within salivary glands.
Collapse
Affiliation(s)
- Olga J Baker
- School of Dentistry, University of Utah , Salt Lake City, UT, USA
| |
Collapse
|
18
|
Venkatesan N, Boggs K, Liu HX. Taste Bud Labeling in Whole Tongue Epithelial Sheet in Adult Mice. Tissue Eng Part C Methods 2016; 22:332-7. [PMID: 26701416 DOI: 10.1089/ten.tec.2015.0377] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Molecular labeling in whole-mount tissues provides an efficient way to obtain general information about the formation, maintenance, degeneration, and regeneration of many organs and tissues. However, labeling of lingual taste buds in whole tongue tissues in adult mice has been problematic because of the strong permeability barrier of the tongue epithelium. In this study, we present a simple method for labeling taste buds in the intact tongue epithelial sheet of an adult mouse. Following intralingual protease injection and incubation, immediate fixation of the tongue on mandible in 4% paraformaldehyde enabled the in situ shape of the tongue epithelium to be well maintained after peeling. The peeled epithelium was accessible to taste bud labeling with a pan-taste cell marker, keratin 8, and a type II taste cell marker, α-gustducin, in all three types of taste papillae, that is, fungiform, foliate, and circumvallate. Overnight incubation of tongue epithelial sheets with primary and secondary antibodies was sufficient for intense labeling of taste buds with both fluorescent and DAB visualizations. Labeled individual taste buds were easy to identify and quantify. This protocol provides an efficient way for phenotypic analyses of taste buds, especially regarding distribution pattern and number.
Collapse
Affiliation(s)
- Nandakumar Venkatesan
- 1 Regenerative Bioscience Center, University of Georgia , Athens, Georgia .,2 Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia , Athens, Georgia
| | - Kristin Boggs
- 1 Regenerative Bioscience Center, University of Georgia , Athens, Georgia .,2 Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia , Athens, Georgia
| | - Hong-Xiang Liu
- 1 Regenerative Bioscience Center, University of Georgia , Athens, Georgia .,2 Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia , Athens, Georgia
| |
Collapse
|
19
|
Capaldo CT, Nusrat A. Claudin switching: Physiological plasticity of the Tight Junction. Semin Cell Dev Biol 2015; 42:22-9. [PMID: 25957515 DOI: 10.1016/j.semcdb.2015.04.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/15/2015] [Accepted: 04/16/2015] [Indexed: 01/22/2023]
Abstract
Tight Junctions (TJs) are multi-molecular complexes in epithelial tissues that regulate paracellular permeability. Within the TJ complex, claudins proteins span the paracellular space to form a seal between adjacent cells. This seal allows regulated passage of ions, fluids, and solutes, contingent upon the complement of claudins expressed. With as many as 27 claudins in the human genome, the TJ seal is complex indeed. This review focuses on changes in claudin expression within the epithelial cells of the gastrointestinal tract, where claudin differentiation results in several physiologically distinct TJs within the lifetime of the cell. We also review mechanistic studies revealing that TJs are highly dynamic, with the potential to undergo molecular remodeling while structurally intact. Therefore, physiologic Tight Junction plasticity involves both the adaptability of claudin expression and gene specific retention in the TJ; a process we term claudin switching.
Collapse
Affiliation(s)
- Christopher T Capaldo
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States
| | - Asma Nusrat
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, United States.
| |
Collapse
|
20
|
Gaillard D, Xu M, Liu F, Millar SE, Barlow LA. β-Catenin Signaling Biases Multipotent Lingual Epithelial Progenitors to Differentiate and Acquire Specific Taste Cell Fates. PLoS Genet 2015; 11:e1005208. [PMID: 26020789 PMCID: PMC4447363 DOI: 10.1371/journal.pgen.1005208] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 04/13/2015] [Indexed: 11/29/2022] Open
Abstract
Continuous taste bud cell renewal is essential to maintain taste function in adults; however, the molecular mechanisms that regulate taste cell turnover are unknown. Using inducible Cre-lox technology, we show that activation of β-catenin signaling in multipotent lingual epithelial progenitors outside of taste buds diverts daughter cells from a general epithelial to a taste bud fate. Moreover, while taste buds comprise 3 morphological types, β-catenin activation drives overproduction of primarily glial-like Type I taste cells in both anterior fungiform (FF) and posterior circumvallate (CV) taste buds, with a small increase in Type II receptor cells for sweet, bitter and umami, but does not alter Type III sour detector cells. Beta-catenin activation in post-mitotic taste bud precursors likewise regulates cell differentiation; forced activation of β-catenin in these Shh+ cells promotes Type I cell fate in both FF and CV taste buds, but likely does so non-cell autonomously. Our data are consistent with a model where β-catenin signaling levels within lingual epithelial progenitors dictate cell fate prior to or during entry of new cells into taste buds; high signaling induces Type I cells, intermediate levels drive Type II cell differentiation, while low levels may drive differentiation of Type III cells. Taste is a fundamental sense that helps the body determine whether food can be ingested. Taste dysfunction can be a side effect of cancer therapies, can result from an alteration of the renewal capacities of the taste buds, and is often associated with psychological distress and malnutrition. Thus, understanding how taste cells renew throughout adult life, i.e. how newly born cells replace old cells as they die, is essential to find potential therapeutic targets to improve taste sensitivity in patients suffering taste dysfunction. Here we show that a specific molecular pathway, Wnt/β-catenin signaling, controls renewal of taste cells by regulating separate stages of taste cell turnover. We show that activating this pathway directs the newly born cells to become primarily a specific taste cell type whose role is to support the other taste cells and help them work efficiently.
Collapse
Affiliation(s)
- Dany Gaillard
- Department of Cell & Developmental Biology, and the Rocky Mountain Taste & Smell Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Mingang Xu
- Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Cell & Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Fei Liu
- Institute for Regenerative Medicine at Scott & White Hospital, Texas A&M University System Health Science Center, Temple, Texas, United States of America
| | - Sarah E. Millar
- Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Linda A. Barlow
- Department of Cell & Developmental Biology, and the Rocky Mountain Taste & Smell Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
| |
Collapse
|
21
|
Molecular mechanisms of taste recognition: considerations about the role of saliva. Int J Mol Sci 2015; 16:5945-74. [PMID: 25782158 PMCID: PMC4394514 DOI: 10.3390/ijms16035945] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 12/13/2022] Open
Abstract
The gustatory system plays a critical role in determining food preferences and food intake, in addition to nutritive, energy and electrolyte balance. Fine tuning of the gustatory system is also crucial in this respect. The exact mechanisms that fine tune taste sensitivity are as of yet poorly defined, but it is clear that various effects of saliva on taste recognition are also involved. Specifically those metabolic polypeptides present in the saliva that were classically considered to be gut and appetite hormones (i.e., leptin, ghrelin, insulin, neuropeptide Y, peptide YY) were considered to play a pivotal role. Besides these, data clearly indicate the major role of several other salivary proteins, such as salivary carbonic anhydrase (gustin), proline-rich proteins, cystatins, alpha-amylases, histatins, salivary albumin and mucins. Other proteins like glucagon-like peptide-1, salivary immunoglobulin-A, zinc-α-2-glycoprotein, salivary lactoperoxidase, salivary prolactin-inducible protein and salivary molecular chaperone HSP70/HSPAs were also expected to play an important role. Furthermore, factors including salivary flow rate, buffer capacity and ionic composition of saliva should also be considered. In this paper, the current state of research related to the above and the overall emerging field of taste-related salivary research alongside basic principles of taste perception is reviewed.
Collapse
|
22
|
Damak S. A blood-bud barrier. Focus on "A permeability barrier surrounds taste buds in lingual epithelia". Am J Physiol Cell Physiol 2014; 308:C20. [PMID: 25273882 DOI: 10.1152/ajpcell.00330.2014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Sami Damak
- Nestlé Research Center, Lausanne, Switzerland
| |
Collapse
|
23
|
Dando R, Pereira E, Kurian M, Barro-Soria R, Chaudhari N, Roper SD. A permeability barrier surrounds taste buds in lingual epithelia. Am J Physiol Cell Physiol 2014; 308:C21-32. [PMID: 25209263 DOI: 10.1152/ajpcell.00157.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003-1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.
Collapse
Affiliation(s)
- Robin Dando
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and
| | - Elizabeth Pereira
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and
| | - Mani Kurian
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and
| | - Rene Barro-Soria
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and
| | - Nirupa Chaudhari
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and Program in Neuroscience, University of Miami, Miami, Florida
| | - Stephen D Roper
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida; and Program in Neuroscience, University of Miami, Miami, Florida
| |
Collapse
|
24
|
Castillo D, Seidel K, Salcedo E, Ahn C, de Sauvage FJ, Klein OD, Barlow LA. Induction of ectopic taste buds by SHH reveals the competency and plasticity of adult lingual epithelium. Development 2014; 141:2993-3002. [PMID: 24993944 DOI: 10.1242/dev.107631] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Taste buds are assemblies of elongated epithelial cells, which are innervated by gustatory nerves that transmit taste information to the brain stem. Taste cells are continuously renewed throughout life via proliferation of epithelial progenitors, but the molecular regulation of this process remains unknown. During embryogenesis, sonic hedgehog (SHH) negatively regulates taste bud patterning, such that inhibition of SHH causes the formation of more and larger taste bud primordia, including in regions of the tongue normally devoid of taste buds. Here, using a Cre-lox system to drive constitutive expression of SHH, we identify the effects of SHH on the lingual epithelium of adult mice. We show that misexpression of SHH transforms lingual epithelial cell fate, such that daughter cells of lingual epithelial progenitors form cell type-replete, onion-shaped taste buds, rather than non-taste, pseudostratified epithelium. These SHH-induced ectopic taste buds are found in regions of the adult tongue previously thought incapable of generating taste organs. The ectopic buds are composed of all taste cell types, including support cells and detectors of sweet, bitter, umami, salt and sour, and recapitulate the molecular differentiation process of endogenous taste buds. In contrast to the well-established nerve dependence of endogenous taste buds, however, ectopic taste buds form independently of both gustatory and somatosensory innervation. As innervation is required for SHH expression by endogenous taste buds, our data suggest that SHH can replace the need for innervation to drive the entire program of taste bud differentiation.
Collapse
Affiliation(s)
- David Castillo
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO 80045, USA Graduate Program in Cell Biology, Stem Cells and Development, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kerstin Seidel
- Program in Craniofacial and Mesenchymal Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, CA 94131, USA
| | - Ernesto Salcedo
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Christina Ahn
- Department of Molecular Biology, Genentech Inc., South San Francisco, CA 94080, USA
| | | | - Ophir D Klein
- Program in Craniofacial and Mesenchymal Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, CA 94131, USA Department of Pediatrics, University of California San Francisco, San Francisco, CA 94131, USA Institute for Human Genetics, University of California San Francisco, San Francisco, CA 94131, USA
| | - Linda A Barlow
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO 80045, USA Graduate Program in Cell Biology, Stem Cells and Development, University of Colorado School of Medicine, Aurora, CO 80045, USA
| |
Collapse
|
25
|
Bui P, Kelly SP. Claudin-6, -10d and -10e contribute to seawater acclimation in the euryhaline puffer fish Tetraodon nigroviridis. ACTA ACUST UNITED AC 2014; 217:1758-67. [PMID: 24526724 DOI: 10.1242/jeb.099200] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Expression profiles of claudin-6, -10d and -10e in the euryhaline teleost fish Tetraodon nigroviridis revealed claudin-6 in brain, eye, gill and skin tissue, while claudin-10d and -10e were found in brain, gill and skin only. In fishes, the gill and skin are important tissue barriers that interface directly with surrounding water, but these organs generally function differently in osmoregulation. Therefore, roles for gill and skin claudin-6, -10d and -10e in the osmoregulatory strategies of T. nigroviridis were investigated. In the gill epithelium, claudin-6, -10d and -10e co-localized with Na(+)-K(+)-ATPase immunoreactive (NKA-ir) ionocytes, and differences in sub-cellular localization could be observed in hypoosmotic (freshwater, FW) versus hyperosmotic (seawater, SW) environments. Claudin-10d and -10e abundance increased in the gills of fish acclimated to SW versus FW, while claudin-6 abundance decreased in the gills of fish acclimated to SW. Taken together with our knowledge of claudin-6 and -10 function in other vertebrates, data support the idea that in SW-acclimated T. nigroviridis, these claudins are abundant in gill ionocytes, where they contribute to the formation of a Na(+) shunt and 'leaky' epithelium, both of which are characteristic of salt-secreting SW fish gills. Skin claudin-10d and -10e abundance also increased in fish acclimated to SW versus those in FW, but so did claudin-6. In skin, claudin-6 was found to co-localize with NKA-ir cells, but claudin-10d and -10e did not. This study provides direct evidence that the gill epithelium contains salinity-responsive tight junction proteins that are abundant primarily in ionocytes. These same proteins also appear to play a role in the osmoregulatory physiology of the epidermis.
Collapse
Affiliation(s)
- Phuong Bui
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - Scott P Kelly
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| |
Collapse
|
26
|
Abstract
Epithelial transport relies on the proper function and regulation of the tight junction (TJ), other-wise uncontrolled paracellular leakage of solutes and water would occur. They also act as a fence against mixing of membrane proteins of the apical and basolateral side. The proteins determining paracellular transport consist of four transmembrane regions, intracellular N and C terminals, one intracellular and two extracellular loops (ECLs). The ECLs interact laterally and with counterparts of the neighboring cell and by this achieve a general sealing function. Two TJ protein families can be distinguished, claudins, comprising 27 members in mammals, and TJ-associated MARVEL proteins (TAMP), comprising occludin, tricellulin, and MarvelD3. They are linked to a multitude of TJ-associated regulatory and scaffolding proteins. The major TJ proteins are classified according to the physiological role they play in enabling or preventing paracellular transport. Many TJ proteins have sealing functions (claudins 1, 3, 5, 11, 14, 19, and tricellulin). In contrast, a significant number of claudins form channels across TJs which feature selectivity for cations (claudins 2, 10b, and 15), anions (claudin-10a and -17), or are permeable to water (claudin-2). For several TJ proteins, function is yet unclear as their effects on epithelial barriers are inconsistent (claudins 4, 7, 8, 16, and occludin). TJs undergo physiological and pathophysiological regulation by altering protein composition or abundance. Major pathophysiological conditions which involve changes in TJ protein composition are (1) effects of pathogens binding to TJ proteins, (2) altered TJ protein composition during inflammation and infection, and (3) altered TJ protein expression in cancers.
Collapse
Affiliation(s)
- Dorothee Günzel
- Institute of Clinical Physiology, Charité, Universtätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität/Humboldt-Universität, Berlin, Germany
| | | |
Collapse
|
27
|
La Sala MS, Hurtado MD, Brown AR, Bohórquez DV, Liddle RA, Herzog H, Zolotukhin S, Dotson CD. Modulation of taste responsiveness by the satiation hormone peptide YY. FASEB J 2013; 27:5022-33. [PMID: 24043261 DOI: 10.1096/fj.13-228064] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has been hypothesized that the peripheral taste system may be modulated in the context of an animal's metabolic state. One purported mechanism for this phenomenon is that circulating gastrointestinal peptides modulate the functioning of the peripheral gustatory system. Recent evidence suggests endocrine signaling in the oral cavity can influence food intake (FI) and satiety. We hypothesized that these hormones may be affecting FI by influencing taste perception. We used immunohistochemistry along with genetic knockout models and the specific reconstitution of peptide YY (PYY) in saliva using gene therapy protocols to identify a role for PYY signaling in taste. We show that PYY is expressed in subsets of taste cells in murine taste buds. We also show, using brief-access testing with PYY knockouts, that PYY signaling modulates responsiveness to bitter-tasting stimuli, as well as to lipid emulsions. We show that salivary PYY augmentation, via viral vector therapy, rescues behavioral responsiveness to a lipid emulsion but not to bitter stimuli and that this response is likely mediated via activation of Y2 receptors localized apically in taste cells. Our findings suggest distinct functions for PYY produced locally in taste cells vs. that circulating systemically.
Collapse
Affiliation(s)
- Michael S La Sala
- 1Department of Neuroscience, University of Florida McKnight Brain Institute, 1149 Newell Dr., Box 100244, Gainesville, FL 32611, USA.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Zolotukhin S. Metabolic hormones in saliva: origins and functions. Oral Dis 2013; 19:219-29. [PMID: 22994880 PMCID: PMC3530011 DOI: 10.1111/odi.12015] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 08/26/2012] [Accepted: 08/27/2012] [Indexed: 12/13/2022]
Abstract
The salivary proteome consists of thousands of proteins, which include, among others, hormonal modulators of energy intake and output. Although the functions of this prominent category of hormones in whole body energy metabolism are well characterized, their functions in the oral cavity, whether as a salivary component, or when expressed in taste cells, are less studied and poorly understood. The respective receptors for the majority of salivary metabolic hormones have been also shown to be expressed in salivary glands (SGs), taste cells, or other cells in the oral mucosa. This review provides a comprehensive account of the gastrointestinal hormones, adipokines, and neuropeptides identified in saliva, SGs, or lingual epithelium, as well as their respective cognate receptors expressed in the oral cavity. Surprisingly, few functions are assigned to salivary metabolic hormones, and these functions are mostly associated with the modulation of taste perception. Because of the well-characterized correlation between impaired oral nutrient sensing and increased energy intake and body mass index, a conceptually provocative point of view is introduced, whereupon it is argued that targeted changes in the composition of saliva could affect whole body metabolism in response to the activation of cognate receptors expressed locally in the oral mucosa.
Collapse
Affiliation(s)
- S Zolotukhin
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| |
Collapse
|
29
|
Abstract
Claudins are tight junction membrane proteins that are expressed in epithelia and endothelia and form paracellular barriers and pores that determine tight junction permeability. This review summarizes our current knowledge of this large protein family and discusses recent advances in our understanding of their structure and physiological functions.
Collapse
Affiliation(s)
- Dorothee Günzel
- Department of Clinical Physiology, Charité, Campus Benjamin Franklin, Berlin, Germany
| | | |
Collapse
|
30
|
Liu Z, Fenech C, Cadiou H, Grall S, Tili E, Laugerette F, Wiencis A, Grosmaitre X, Montmayeur JP. Identification of new binding partners of the chemosensory signaling protein Gγ13 expressed in taste and olfactory sensory cells. Front Cell Neurosci 2012; 6:26. [PMID: 22737109 PMCID: PMC3380295 DOI: 10.3389/fncel.2012.00026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/31/2012] [Indexed: 01/19/2023] Open
Abstract
Tastant detection in the oral cavity involves selective receptors localized at the apical extremity of a subset of specialized taste bud cells called taste receptor cells (TRCs). The identification of the genes coding for the taste receptors involved in this process have greatly improved our understanding of the molecular mechanisms underlying detection. However, how these receptors signal in TRCs, and whether the components of the signaling cascades interact with each other or are organized in complexes is mostly unexplored. Here we report on the identification of three new binding partners for the mouse G protein gamma 13 subunit (Gγ13), a component of the bitter taste receptors signaling cascade. For two of these Gγ13 associated proteins, namely GOPC and MPDZ, we describe the expression in taste bud cells for the first time. Furthermore, we demonstrate by means of a yeast two-hybrid interaction assay that the C terminal PDZ binding motif of Gγ13 interacts with selected PDZ domains in these proteins. In the case of the PDZ domain-containing protein zona occludens-1 (ZO-1), a major component of the tight junction defining the boundary between the apical and baso-lateral region of TRCs, we identified the first PDZ domain as the site of strong interaction with Gγ13. This association was further confirmed by co-immunoprecipitation experiments in HEK 293 cells. In addition, we present immunohistological data supporting partial co-localization of GOPC, MPDZ, or ZO-1, and Gγ13 in taste buds cells. Finally, we extend this observation to olfactory sensory neurons (OSNs), another type of chemosensory cells known to express both ZO-1 and Gγ13. Taken together our results implicate these new interaction partners in the sub-cellular distribution of Gγ13 in olfactory and gustatory primary sensory cells.
Collapse
Affiliation(s)
- Zhenhui Liu
- Chemosensory Perception, Centre des Sciences du Goût et de l'Alimentation, UMR-6265 CNRS, UMR-1324 INRA Dijon, France
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Maruyama Y, Yasuda R, Kuroda M, Eto Y. Kokumi substances, enhancers of basic tastes, induce responses in calcium-sensing receptor expressing taste cells. PLoS One 2012; 7:e34489. [PMID: 22511946 PMCID: PMC3325276 DOI: 10.1371/journal.pone.0034489] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/01/2012] [Indexed: 11/19/2022] Open
Abstract
Recently, we reported that calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Furthermore, we found that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances. In this study, we elucidated the receptor cells for kokumi substances, and their physiological properties. For this purpose, we used Calcium Green-1 loaded mouse taste cells in lingual tissue slices and confocal microscopy. Kokumi substances, applied focally around taste pores, induced an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)) in a subset of taste cells. These responses were inhibited by pretreatment with the CaSR inhibitor, NPS2143. However, the kokumi substance-induced responses did not require extracellular Ca(2+). CaSR-expressing taste cells are a different subset of cells from the T1R3-expressing umami or sweet taste receptor cells. These observations indicate that CaSR-expressing taste cells are the primary detectors of kokumi substances, and that they are an independent population from the influenced basic taste receptor cells, at least in the case of sweet and umami.
Collapse
Affiliation(s)
- Yutaka Maruyama
- Institute for Innovation, Ajinomoto Co, Inc, Kawasaki, Japan.
| | | | | | | |
Collapse
|
32
|
|
33
|
Hypertonicity augments bullfrog taste nerve responses to inorganic salts. Pflugers Arch 2012; 463:845-51. [PMID: 22422087 DOI: 10.1007/s00424-012-1097-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/03/2012] [Accepted: 03/04/2012] [Indexed: 10/28/2022]
Abstract
The tonicity of taste stimulating solutions has been usually ignored, though taste substances themselves yielded the tonicity. We investigated the effect of hypertonicity on bullfrog taste nerve responses to inorganic salts by adding nonelectrolytes such as urea and sucrose that elicited no taste nerve responses. Here, we show that hypertonicity alters bullfrog taste nerve-response magnitude and firing pattern. The addition of urea or sucrose enhances the taste nerve-response magnitude to NaCl and shifts the concentration-response curve to the left. The effect of hypertonicity on responses to CaCl(2) is bimodal; hypertonicity suppresses CaCl(2) responses at concentrations less than ~30 mM and enhances them at concentrations greater than ~30 mM. The hypertonicity also enhances response magnitude to other monovalent salts. The extent of the enhancing effects depends on the difference between the mobility of the cation and anion in the salt. We quantitatively suggest that both the enhancing and suppressing effects result from the magnitude and direction of local circuit currents generated by diffusion potentials across tight junctions surrounding taste receptor cells.
Collapse
|
34
|
Nishiyama M, Yuki S, Fukano C, Sako H, Miyamoto T, Tomooka Y. Attempt to develop taste bud models in three-dimensional culture. Zoolog Sci 2011; 28:623-32. [PMID: 21882950 DOI: 10.2108/zsj.28.623] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Taste buds are the end organs of taste located in the gustatory papillae, which occur on the surface of the oral cavity. The goal of the present study was to establish a culture model mimicking the lingual taste bud of the mouse. To this end, three cell lines were employed: taste bud-derived cell lines (TBD cell lines), a lingual epithelial cell-derived cell line (20A cell line), and a mesenchymal cell-derived cell line (TMD cell line). TBD cells embedded in collagen gel formed three-dimensional clusters, which had an internal cavity equipped with a tight junction-like structure, a microvilluslike structure, and a laminin-positive layer surrounding the cluster. The cells with this epitheliumlike morphology expressed marker proteins of taste cells: gustducin and NCAM. TBD cells formed a monolayer on collagen gel when they were co-cultured with TMD cells. TBD, 20A, and TMD cell lines were maintained in a triple cell co-culture, in which TBD cells were pre-seeded as aggregates or in suspension on the collagen gel containing TMD cells, and 20A cells were laid over the TBD cells. TBD cells in the triple cell co-culture expressed NCAM. This result suggests that co-cultured TBD cells exhibited a characteristic of Type III taste cells. The culture model would be useful to study morphogenesis and functions of the gustatory organ.
Collapse
Affiliation(s)
- Miyako Nishiyama
- Division of Material and Biological Sciences, Graduate School of Science, Bunkyo-ku, Tokyo, Japan
| | | | | | | | | | | |
Collapse
|
35
|
Abstract
Peptide YY3-36 is a satiation hormone released postprandially into the bloodstream from L-endocrine cells in the gut epithelia. In the current report, we demonstrate PYY3-36 is also present in murine as well as in human saliva. In mice, salivary PYY3-36 derives from plasma and is also synthesized in the taste cells in taste buds of the tongue. Moreover, the cognate receptor Y2R is abundantly expressed in the basal layer of the progenitor cells of the tongue epithelia and von Ebner's gland. The acute augmentation of salivary PYY3-36 induced stronger satiation as demonstrated in feeding behavioral studies. The effect is mediated through the activation of the specific Y2 receptor expressed in the lingual epithelial cells. In a long-term study involving diet-induced obese (DIO) mice, a sustained increase in PYY3-36 was achieved using viral vector-mediated gene delivery targeting salivary glands. The chronic increase in salivary PYY3-36 resulted in a significant long-term reduction in food intake (FI) and body weight (BW). Thus this study provides evidence for new functions of the previously characterized gut peptide PYY3-36 suggesting a potential simple and efficient alternative therapeutic approach for the treatment of obesity.
Collapse
|
36
|
Meyerhof W, Born S, Brockhoff A, Behrens M. Molecular biology of mammalian bitter taste receptors. A review. FLAVOUR FRAG J 2011. [DOI: 10.1002/ffj.2041] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wolfgang Meyerhof
- German Institute of Human Nutrition Potsdam-Rehbruecke; Department of Molecular Genetics; Arthur-Scheunert-Allee 114-116; D-14558; Nuthetal; Germany
| | - Stephan Born
- German Institute of Human Nutrition Potsdam-Rehbruecke; Department of Molecular Genetics; Arthur-Scheunert-Allee 114-116; D-14558; Nuthetal; Germany
| | - Anne Brockhoff
- German Institute of Human Nutrition Potsdam-Rehbruecke; Department of Molecular Genetics; Arthur-Scheunert-Allee 114-116; D-14558; Nuthetal; Germany
| | - Maik Behrens
- German Institute of Human Nutrition Potsdam-Rehbruecke; Department of Molecular Genetics; Arthur-Scheunert-Allee 114-116; D-14558; Nuthetal; Germany
| |
Collapse
|
37
|
|
38
|
Abstract
Taste buds are aggregates of 50–100 polarized neuroepithelial cells that detect nutrients and other compounds. Combined analyses of gene expression and cellular function reveal an elegant cellular organization within the taste bud. This review discusses the functional classes of taste cells, their cell biology, and current thinking on how taste information is transmitted to the brain.
Collapse
Affiliation(s)
- Nirupa Chaudhari
- Department of Physiology and Biophysics, and Program in Neurosciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | | |
Collapse
|
39
|
Dvoryanchikov G, Sinclair MS, Perea-Martinez I, Wang T, Chaudhari N. Inward rectifier channel, ROMK, is localized to the apical tips of glial-like cells in mouse taste buds. J Comp Neurol 2009; 517:1-14. [PMID: 19708028 DOI: 10.1002/cne.22152] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cells in taste buds are closely packed, with little extracellular space. Tight junctions and other barriers further limit permeability and may result in buildup of extracellular K(+) following action potentials. In many tissues, inwardly rectifying K channels such as the renal outer medullary K (ROMK) channel (also called Kir1.1 and derived from the Kcnj1 gene) help to redistribute K(+). Using reverse-transcription polymerase chain reaction (RT-PCR), we defined ROMK splice variants in mouse kidney and report here the expression of a single one of these, ROMK2, in a subset of mouse taste cells. With quantitative (q)RT-PCR, we show the abundance of ROMK mRNA in taste buds is vallate > foliate > > palate > > fungiform. ROMK protein follows the same pattern of prevalence as mRNA, and is essentially undetectable by immunohistochemistry in fungiform taste buds. ROMK protein is localized to the apical tips of a subset of taste cells. Using tissues from PLCbeta2-GFP and GAD1-GFP transgenic mice, we show that ROMK is not found in PLCbeta2-expressing type II/receptor cells or in GAD1-expressing type III/presynaptic cells. Instead, ROMK is found, by single-cell RT-PCR and immunofluorescence, in most cells that are positive for the taste glial cell marker, Ectonucleotidase2. ROMK is precisely localized to the apical tips of these cells, at and above apical tight junctions. We propose that in taste buds, ROMK in type I/glial-like cells may serve a homeostatic function, excreting excess K(+) through the apical pore, and allowing excitable taste cells to maintain a hyperpolarized resting membrane potential.
Collapse
Affiliation(s)
- Gennady Dvoryanchikov
- Department of Physiology & Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | | | | | | | | |
Collapse
|
40
|
Long DJ, Devantier HR, Brennan FX, Bryant RW, Salemme FR, Palmer RK. Pharmacologic antagonism of the oral aversive taste-directed response to capsaicin in a mouse brief access taste aversion assay. J Pharmacol Exp Ther 2009; 332:525-30. [PMID: 19903834 DOI: 10.1124/jpet.109.155416] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Chemosensory signaling by the tongue is a primary determinant of ingestive behavior and is mediated by specific interactions between tastant molecules and G protein-coupled and ion channel receptors. The functional relationship between tastant and receptor should be amenable to pharmacologic methods and manipulation. We have performed a pharmacologic characterization of the taste-directed licking of mice presented with solutions of capsaicin and other transient receptor potential vanilloid-1 (TRPV1) agonists using a brief access taste aversion assay. Dose-response functions for lick-rate suppression were established for capsaicin (EC(50) = 0.5 microM), piperine (EC(50) = 2 muM), and resiniferatoxin (EC(50) = 0.02 microM). Little or no effect on lick rate was observed in response to the full TRPV1 agonist olvanil. Capsaicin lick rates of wild-type and transient receptor potential melastatin-5 (TRPM5) knockout mice were equivalent, indicating that TRPM5, a critical component of aversive signaling for many bitter tastants, did not contribute to the capsaicin taste response. The selective TRPV1 antagonists N-(4-tertiarybutylphenyl)-4-(3-chloropyridin-2-yl)tetrahydropyrazine-1(2H)-carbox-amide (10 microM) and (E)-3-(4-t-butylphenyl)-N-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)acrylamide (AMG9810) (10 microM) effectively blocked capsaicin- and piperine-mediated lick suppression. However, (E)-3-(4-chlorophenyl)-N-(3-methoxyphenyl)-N-phenylprop-2-enamide (SB 366791) and capsazepine, also TRPV1 antagonists, were without effect at test concentrations of up to 30 and 100 microM, respectively. Our results demonstrate that TRPV1-mediated oral aversiveness presents a pharmacologic profile differing from what has been reported previously for TRPV1 pain signaling and, furthermore, that aversive tastes can be evaluated and controlled pharmacologically.
Collapse
Affiliation(s)
- Daniel J Long
- Discovery Research, RedPoint Bio Corporation, Ewing, New Jersey, USA
| | | | | | | | | | | |
Collapse
|
41
|
Gao N, Lu M, Echeverri F, Laita B, Kalabat D, Williams ME, Hevezi P, Zlotnik A, Moyer BD. Voltage-gated sodium channels in taste bud cells. BMC Neurosci 2009; 10:20. [PMID: 19284629 PMCID: PMC2660338 DOI: 10.1186/1471-2202-10-20] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Accepted: 03/12/2009] [Indexed: 12/19/2022] Open
Abstract
Background Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown. Results We describe the molecular and histological expression profiles of cation channels involved in electrical signal transmission from apical to basolateral membrane domains. TRPM5 was positioned immediately beneath tight junctions to receive calcium signals originating from sweet, bitter, and umami receptor activation, while PKD2L1 was positioned at the taste pore. Using mouse taste bud and lingual epithelial cells collected by laser capture microdissection, SCN2A, SCN3A, and SCN9A voltage-gated sodium channel transcripts were expressed in taste tissue. SCN2A, SCN3A, and SCN9A were expressed beneath tight junctions in subsets of taste cells. SCN3A and SCN9A were expressed in TRPM5 cells, while SCN2A was expressed in TRPM5 and PKD2L1 cells. HCN4, a gene previously implicated in sour taste, was expressed in PKD2L1 cells and localized to cell processes beneath the taste pore. Conclusion SCN2A, SCN3A and SCN9A voltage-gated sodium channels are positioned to sense initial depolarizing signals stemming from taste receptor activation and initiate taste cell action potentials. SCN2A, SCN3A and SCN9A gene products likely account for the tetrodotoxin-sensitive sodium currents in taste receptor cells.
Collapse
Affiliation(s)
- Na Gao
- Senomyx, Inc, 4767 Nexus Centre Drive, San Diego, CA 92121, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Gao N, Lu M, Echeverri F, Laita B, Kalabat D, Williams ME, Hevezi P, Zlotnik A, Moyer BD. Voltage-gated sodium channels in taste bud cells. BMC Neurosci 2009. [PMID: 19284629 DOI: 10.1186/1471‐2202‐10‐20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown. RESULTS We describe the molecular and histological expression profiles of cation channels involved in electrical signal transmission from apical to basolateral membrane domains. TRPM5 was positioned immediately beneath tight junctions to receive calcium signals originating from sweet, bitter, and umami receptor activation, while PKD2L1 was positioned at the taste pore. Using mouse taste bud and lingual epithelial cells collected by laser capture microdissection, SCN2A, SCN3A, and SCN9A voltage-gated sodium channel transcripts were expressed in taste tissue. SCN2A, SCN3A, and SCN9A were expressed beneath tight junctions in subsets of taste cells. SCN3A and SCN9A were expressed in TRPM5 cells, while SCN2A was expressed in TRPM5 and PKD2L1 cells. HCN4, a gene previously implicated in sour taste, was expressed in PKD2L1 cells and localized to cell processes beneath the taste pore. CONCLUSION SCN2A, SCN3A and SCN9A voltage-gated sodium channels are positioned to sense initial depolarizing signals stemming from taste receptor activation and initiate taste cell action potentials. SCN2A, SCN3A and SCN9A gene products likely account for the tetrodotoxin-sensitive sodium currents in taste receptor cells.
Collapse
Affiliation(s)
- Na Gao
- Senomyx, Inc, 4767 Nexus Centre Drive, San Diego, CA 92121, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Yoshida R, Horio N, Murata Y, Yasumatsu K, Shigemura N, Ninomiya Y. NaCl responsive taste cells in the mouse fungiform taste buds. Neuroscience 2009; 159:795-803. [PMID: 19167465 DOI: 10.1016/j.neuroscience.2008.12.052] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 12/29/2008] [Accepted: 12/30/2008] [Indexed: 11/25/2022]
Abstract
Previous studies have demonstrated that rodents' chorda tympani (CT) nerve fibers responding to NaCl can be classified according to their sensitivities to the epithelial sodium channel (ENaC) blocker amiloride into two groups: amiloride-sensitive (AS) and -insensitive (AI). The AS fibers were shown to respond specifically to NaCl, whereas AI fibers broadly respond to various electrolytes, including NaCl. These data suggest that salt taste transduction in taste cells may be composed of at least two different systems; AS and AI ones. To further address this issue, we investigated the responses to NaCl, KCl and HCl and the amiloride sensitivity of mouse fungiform papilla taste bud cells which are innervated by the CT nerve. Comparable with the CT data, the results indicated that 56 NaCl-responsive cells tested were classified into two groups; 25 cells ( approximately 44%) narrowly responded to NaCl and their NaCl response were inhibited by amiloride (AS cells), whereas the remaining 31 cells ( approximately 56%) responded not only to NaCl, but to KCl and/or HCl and showed no amiloride inhibition of NaCl responses (AI cells). Amiloride applied to the basolateral side of taste cells had no effect on NaCl responses in the AS and AI cells. Single cell reverse transcription-polymerase chain reaction (RT-PCR) experiments indicated that ENaC subunit mRNA was expressed in a subset of AS cells. These findings suggest that the mouse fungiform taste bud is composed of AS and AI cells that can transmit taste information differently to their corresponding types of CT fibers, and apical ENaCs may be involved in the NaCl responses of AS cells.
Collapse
Affiliation(s)
- R Yoshida
- Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Fukuoka, Japan
| | | | | | | | | | | |
Collapse
|
44
|
|
45
|
Krause G, Winkler L, Mueller SL, Haseloff RF, Piontek J, Blasig IE. Structure and function of claudins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1778:631-45. [PMID: 18036336 DOI: 10.1016/j.bbamem.2007.10.018] [Citation(s) in RCA: 582] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 10/18/2007] [Accepted: 10/19/2007] [Indexed: 01/09/2023]
Abstract
Claudins are tetraspan transmembrane proteins of tight junctions. They determine the barrier properties of this type of cell-cell contact existing between the plasma membranes of two neighbouring cells, such as occurring in endothelia or epithelia. Claudins can completely tighten the paracellular cleft for solutes, and they can form paracellular ion pores. It is assumed that the extracellular loops specify these claudin functions. It is hypothesised that the larger first extracellular loop is critical for determining the paracellular tightness and the selective ion permeability. The shorter second extracellular loop may cause narrowing of the paracellular cleft and have a holding function between the opposing cell membranes. Sequence analysis of claudins has led to differentiation into two groups, designated as classic claudins (1-10, 14, 15, 17, 19) and non-classic claudins (11-13, 16, 18, 20-24), according to their degree of sequence similarity. This is also reflected in the derived sequence-structure function relationships for extracellular loops 1 and 2. The concepts evolved from these findings and first tentative molecular models for homophilic interactions may explain the different functional contribution of the two extracellular loops at tight junctions.
Collapse
Affiliation(s)
- Gerd Krause
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | | | | | | | | | | |
Collapse
|