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Wood RM, Vasquez EL, Goyins KA, Gutierrez Kuri E, Connelly K, Humayun S, Macpherson LJ. Cyclophosphamide induces the loss of taste bud innervation in mice. Chem Senses 2024; 49:bjae010. [PMID: 38421250 PMCID: PMC10929424 DOI: 10.1093/chemse/bjae010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Indexed: 03/02/2024] Open
Abstract
Many common chemotherapeutics produce disruptions in the sense of taste which can lead to loss of appetite, nutritional imbalance, and reduced quality of life, especially if taste loss persists after treatment ends. Cyclophosphamide (CYP), an alkylating chemotherapeutic agent, affects taste sensitivity through its cytotoxic effects on mature taste receptor cells (TRCs) and on taste progenitor cell populations, retarding the capacity to replace TRCs. Mechanistic studies have focused primarily on taste cells, however, taste signaling requires communication between TRCs and the gustatory nerve fibers that innervate them. Here, we evaluate cyclophosphamide's effects on the peripheral gustatory nerve fibers that innervate the taste buds. Following histological analysis of tongue tissues, we find that CYP reduces innervation within the fungiform and circumvallates taste buds within 4 days after administration. To better understand the dynamics of the denervation process, we used 2-photon intravital imaging to visualize the peripheral gustatory nerve fibers within individual fungiform taste buds up to 20 days after CYP treatment. We find that gustatory fibers retract from the taste bud properly but are maintained within the central papilla core. These data indicate that in addition to TRCs, gustatory nerve fibers are also affected by CYP treatment. Because the connectivity between TRCs and gustatory neurons must be re-established for proper function, gustatory fibers should continue to be included in future studies to understand the mechanisms leading to chemotherapy-induced persistent taste loss.
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Affiliation(s)
- Ryan M Wood
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
- The Graduate Program in Neuroscience, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Erin L Vasquez
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Krystal A Goyins
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
- The Graduate Program in Developmental and Regenerative Sciences, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Eduardo Gutierrez Kuri
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Kevin Connelly
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Saima Humayun
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
| | - Lindsey J Macpherson
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
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2
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Doyle ME, Premathilake HU, Yao Q, Mazucanti CH, Egan JM. Physiology of the tongue with emphasis on taste transduction. Physiol Rev 2023; 103:1193-1246. [PMID: 36422992 PMCID: PMC9942923 DOI: 10.1152/physrev.00012.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The tongue is a complex multifunctional organ that interacts and senses both interoceptively and exteroceptively. Although it is easily visible to almost all of us, it is relatively understudied and what is in the literature is often contradictory or is not comprehensively reported. The tongue is both a motor and a sensory organ: motor in that it is required for speech and mastication, and sensory in that it receives information to be relayed to the central nervous system pertaining to the safety and quality of the contents of the oral cavity. Additionally, the tongue and its taste apparatus form part of an innate immune surveillance system. For example, loss or alteration in taste perception can be an early indication of infection as became evident during the present global SARS-CoV-2 pandemic. Here, we particularly emphasize the latest updates in the mechanisms of taste perception, taste bud formation and adult taste bud renewal, and the presence and effects of hormones on taste perception, review the understudied lingual immune system with specific reference to SARS-CoV-2, discuss nascent work on tongue microbiome, as well as address the effect of systemic disease on tongue structure and function, especially in relation to taste.
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Affiliation(s)
- Máire E Doyle
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Hasitha U Premathilake
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Qin Yao
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Caio H Mazucanti
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Josephine M Egan
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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Kumari A, Mistretta CM. Anterior and Posterior Tongue Regions and Taste Papillae: Distinct Roles and Regulatory Mechanisms with an Emphasis on Hedgehog Signaling and Antagonism. Int J Mol Sci 2023; 24:4833. [PMID: 36902260 PMCID: PMC10002505 DOI: 10.3390/ijms24054833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/21/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
Sensory receptors across the entire tongue are engaged during eating. However, the tongue has distinctive regions with taste (fungiform and circumvallate) and non-taste (filiform) organs that are composed of specialized epithelia, connective tissues, and innervation. The tissue regions and papillae are adapted in form and function for taste and somatosensation associated with eating. It follows that homeostasis and regeneration of distinctive papillae and taste buds with particular functional roles require tailored molecular pathways. Nonetheless, in the chemosensory field, generalizations are often made between mechanisms that regulate anterior tongue fungiform and posterior circumvallate taste papillae, without a clear distinction that highlights the singular taste cell types and receptors in the papillae. We compare and contrast signaling regulation in the tongue and emphasize the Hedgehog pathway and antagonists as prime examples of signaling differences in anterior and posterior taste and non-taste papillae. Only with more attention to the roles and regulatory signals for different taste cells in distinct tongue regions can optimal treatments for taste dysfunctions be designed. In summary, if tissues are studied from one tongue region only, with associated specialized gustatory and non-gustatory organs, an incomplete and potentially misleading picture will emerge of how lingual sensory systems are involved in eating and altered in disease.
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Affiliation(s)
- Archana Kumari
- Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA
| | - Charlotte M. Mistretta
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA
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Shechtman LA, Scott JK, Larson ED, Isner TJ, Johnson BJ, Gaillard D, Dempsey PJ, Barlow LA. High Sox2 expression predicts taste lineage competency of lingual progenitors in vitro. Development 2023; 150:dev201375. [PMID: 36794954 PMCID: PMC10112921 DOI: 10.1242/dev.201375] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/19/2023] [Indexed: 02/17/2023]
Abstract
Taste buds on the tongue contain taste receptor cells (TRCs) that detect sweet, sour, salty, umami and bitter stimuli. Like non-taste lingual epithelium, TRCs are renewed from basal keratinocytes, many of which express the transcription factor SOX2. Genetic lineage tracing has shown that SOX2+ lingual progenitors give rise to both taste and non-taste lingual epithelium in the posterior circumvallate taste papilla (CVP) of mice. However, SOX2 is variably expressed among CVP epithelial cells, suggesting that their progenitor potential may vary. Using transcriptome analysis and organoid technology, we show that cells expressing SOX2 at higher levels are taste-competent progenitors that give rise to organoids comprising both TRCs and lingual epithelium. Conversely, organoids derived from progenitors that express SOX2 at lower levels are composed entirely of non-taste cells. Hedgehog and WNT/β-catenin are required for taste homeostasis in adult mice. However, manipulation of hedgehog signaling in organoids has no impact on TRC differentiation or progenitor proliferation. By contrast, WNT/β-catenin promotes TRC differentiation in vitro in organoids derived from higher but not low SOX2+ expressing progenitors.
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Affiliation(s)
- Lauren A. Shechtman
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jennifer K. Scott
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Eric D. Larson
- Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Trevor J. Isner
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Cell Biology, Stem Cells and Development Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Bryan J. Johnson
- Cell Biology, Stem Cells and Development Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Dany Gaillard
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Peter J. Dempsey
- Cell Biology, Stem Cells and Development Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Section of Developmental Biology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Linda A. Barlow
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Cell Biology, Stem Cells and Development Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Barlow LA. The sense of taste: Development, regeneration, and dysfunction. WIREs Mech Dis 2022; 14:e1547. [PMID: 34850604 PMCID: PMC11152580 DOI: 10.1002/wsbm.1547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/28/2021] [Accepted: 10/21/2021] [Indexed: 12/12/2022]
Abstract
Gustation or the sense of taste is a primary sense, which functions as a gatekeeper for substances that enter the body. Animals, including humans, ingest foods that contain appetitive taste stimuli, including those that have sweet, moderately salty and umami (glutamate) components, and tend to avoid bitter-tasting items, as many bitter compounds are toxic. Taste is mediated by clusters of heterogeneous taste receptors cells (TRCs) organized as taste buds on the tongue, and these convey taste information from the oral cavity to higher order brain centers via the gustatory sensory neurons of the seventh and ninth cranial ganglia. One remarkable aspect of taste is that taste perception is mostly uninterrupted throughout life yet TRCs within buds are constantly renewed; every 1-2 months all taste cells have been steadily replaced. In the past decades we have learned a substantial amount about the cellular and molecular regulation of taste bud cell renewal, and how taste buds are initially established during embryogenesis. Here I review more recent findings pertaining to taste development and regeneration, as well as discuss potential mechanisms underlying taste dysfunction that often occurs with disease or its treatment. This article is categorized under: Infectious Diseases > Stem Cells and Development Cancer > Stem Cells and Development Neurological Diseases > Stem Cells and Development.
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Affiliation(s)
- Linda A Barlow
- Department of Cell & Developmental Biology, Graduate Program in Cell Biology, Stem Cells & Development, and the Rocky Mountain Taste & Smell Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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Lakshmanan HG, Miller E, White-Canale A, McCluskey LP. Immune responses in the injured olfactory and gustatory systems: a role in olfactory receptor neuron and taste bud regeneration? Chem Senses 2022; 47:bjac024. [PMID: 36152297 PMCID: PMC9508897 DOI: 10.1093/chemse/bjac024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sensory cells that specialize in transducing olfactory and gustatory stimuli are renewed throughout life and can regenerate after injury unlike their counterparts in the mammalian retina and auditory epithelium. This uncommon capacity for regeneration offers an opportunity to understand mechanisms that promote the recovery of sensory function after taste and smell loss. Immune responses appear to influence degeneration and later regeneration of olfactory sensory neurons and taste receptor cells. Here we review surgical, chemical, and inflammatory injury models and evidence that immune responses promote or deter chemosensory cell regeneration. Macrophage and neutrophil responses to chemosensory receptor injury have been the most widely studied without consensus on their net effects on regeneration. We discuss possible technical and biological reasons for the discrepancy, such as the difference between peripheral and central structures, and suggest directions for progress in understanding immune regulation of chemosensory regeneration. Our mechanistic understanding of immune-chemosensory cell interactions must be expanded before therapies can be developed for recovering the sensation of taste and smell after head injury from traumatic nerve damage and infection. Chemosensory loss leads to decreased quality of life, depression, nutritional challenges, and exposure to environmental dangers highlighting the need for further studies in this area.
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Affiliation(s)
- Hari G Lakshmanan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Elayna Miller
- Department of Medical Illustration, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - AnnElizabeth White-Canale
- Department of Medical Illustration, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Lynnette P McCluskey
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
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