1
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Bhuiyan SA, Xu M, Yang L, Semizoglou E, Bhatia P, Pantaleo KI, Tochitsky I, Jain A, Erdogan B, Blair S, Cat V, Mwirigi JM, Sankaranarayanan I, Tavares-Ferreira D, Green U, McIlvried LA, Copits BA, Bertels Z, Del Rosario JS, Widman AJ, Slivicki RA, Yi J, Sharif-Naeini R, Woolf CJ, Lennerz JK, Whited JL, Price TJ, Robert W Gereau Iv, Renthal W. Harmonized cross-species cell atlases of trigeminal and dorsal root ganglia. SCIENCE ADVANCES 2024; 10:eadj9173. [PMID: 38905344 DOI: 10.1126/sciadv.adj9173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 05/16/2024] [Indexed: 06/23/2024]
Abstract
Sensory neurons in the dorsal root ganglion (DRG) and trigeminal ganglion (TG) are specialized to detect and transduce diverse environmental stimuli to the central nervous system. Single-cell RNA sequencing has provided insights into the diversity of sensory ganglia cell types in rodents, nonhuman primates, and humans, but it remains difficult to compare cell types across studies and species. We thus constructed harmonized atlases of the DRG and TG that describe and facilitate comparison of 18 neuronal and 11 non-neuronal cell types across six species and 31 datasets. We then performed single-cell/nucleus RNA sequencing of DRG from both human and the highly regenerative axolotl and found that the harmonized atlas also improves cell type annotation, particularly of sparse neuronal subtypes. We observed that the transcriptomes of sensory neuron subtypes are broadly similar across vertebrates, but the expression of functionally important neuropeptides and channels can vary notably. The resources presented here can guide future studies in comparative transcriptomics, simplify cell-type nomenclature differences across studies, and help prioritize targets for future analgesic development.
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Affiliation(s)
- Shamsuddin A Bhuiyan
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Mengyi Xu
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Alan Edwards Center for Research on Pain and Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Lite Yang
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Evangelia Semizoglou
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Parth Bhatia
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Katerina I Pantaleo
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ivan Tochitsky
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir., Boston, MA 02115, USA
| | - Aakanksha Jain
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir., Boston, MA 02115, USA
| | - Burcu Erdogan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Steven Blair
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Victor Cat
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Juliet M Mwirigi
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Diana Tavares-Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Ursula Green
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114, USA
| | - Lisa A McIlvried
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Bryan A Copits
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Zachariah Bertels
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - John S Del Rosario
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Allie J Widman
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Richard A Slivicki
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Jiwon Yi
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Reza Sharif-Naeini
- Alan Edwards Center for Research on Pain and Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir., Boston, MA 02115, USA
| | - Jochen K Lennerz
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114, USA
| | - Jessica L Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Robert W Gereau Iv
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - William Renthal
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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2
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Zhu K, Wang L, Liao T, Li W, Zhou J, You Y, Shi J. Progress in the development of TRPV1 small-molecule antagonists: Novel Strategies for pain management. Eur J Med Chem 2023; 261:115806. [PMID: 37713804 DOI: 10.1016/j.ejmech.2023.115806] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/17/2023]
Abstract
Transient receptor potential vanilloid 1 (TRPV1) channels are widely distributed in sensory nerve endings, the central nervous system, and other tissues, functioning as ion channel proteins responsive to thermal pain and chemical stimuli. In recent years, the TRPV1 receptor has garnered significant interest as a potential therapeutic approach for various pain-related disorders, particularly TRPV1 antagonists. The present review offers a comprehensive, systematic exploration of both first- and second-generation TRPV1 antagonists in the context of pain management. Antagonists are categorized and explicated according to their structural characteristics. Detailed examination of binding modes, structural features, and pharmacological activities, alongside a critical appraisal of the advantages and limitations inherent to typical compounds within each structural category, are undertaken. Detailed discussions of the binding modes, structural features, pharmacological activities, advantages, and limitations of typical compounds within each structural category offer valuable insights and guidance for the future research and development of safer, more effective, and more targeted TRPV1 antagonists.
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Affiliation(s)
- Kun Zhu
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, China
| | - Lin Wang
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China; State Key Laboratory of Biotherapy, Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - TingTing Liao
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, China
| | - Wen Li
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, China
| | - Jing Zhou
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, China
| | - Yaodong You
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, China; TCM Regulating Metabolic Diseases Key Laboratory of Sichuan Province, Chengdu, 610072, China.
| | - Jianyou Shi
- Department of Pharmacy, Personalized Drug Therapy Key Laboratory of Sichuan Province, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China; State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
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3
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Bhuiyan SA, Xu M, Yang L, Semizoglou E, Bhatia P, Pantaleo KI, Tochitsky I, Jain A, Erdogan B, Blair S, Cat V, Mwirigi JM, Sankaranarayanan I, Tavares-Ferreira D, Green U, McIlvried LA, Copits BA, Bertels Z, Del Rosario JS, Widman AJ, Slivicki RA, Yi J, Woolf CJ, Lennerz JK, Whited JL, Price TJ, Gereau RW, Renthal W. Harmonized cross-species cell atlases of trigeminal and dorsal root ganglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.04.547740. [PMID: 37461736 PMCID: PMC10350076 DOI: 10.1101/2023.07.04.547740] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Peripheral sensory neurons in the dorsal root ganglion (DRG) and trigeminal ganglion (TG) are specialized to detect and transduce diverse environmental stimuli including touch, temperature, and pain to the central nervous system. Recent advances in single-cell RNA-sequencing (scRNA-seq) have provided new insights into the diversity of sensory ganglia cell types in rodents, non-human primates, and humans, but it remains difficult to compare transcriptomically defined cell types across studies and species. Here, we built cross-species harmonized atlases of DRG and TG cell types that describe 18 neuronal and 11 non-neuronal cell types across 6 species and 19 studies. We then demonstrate the utility of this harmonized reference atlas by using it to annotate newly profiled DRG nuclei/cells from both human and the highly regenerative axolotl. We observe that the transcriptomic profiles of sensory neuron subtypes are broadly similar across vertebrates, but the expression of functionally important neuropeptides and channels can vary notably. The new resources and data presented here can guide future studies in comparative transcriptomics, simplify cell type nomenclature differences across studies, and help prioritize targets for future pain therapy development.
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Affiliation(s)
- Shamsuddin A Bhuiyan
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Mengyi Xu
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Alan Edwards Center for Research on Pain and Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Lite Yang
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Evangelia Semizoglou
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Parth Bhatia
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Katerina I Pantaleo
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ivan Tochitsky
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir. Boston, MA 02115
| | - Aakanksha Jain
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir. Boston, MA 02115
| | - Burcu Erdogan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Steven Blair
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Victor Cat
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Juliet M Mwirigi
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Diana Tavares-Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Ursula Green
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114
| | - Lisa A McIlvried
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Bryan A Copits
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Zachariah Bertels
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - John S Del Rosario
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Allie J Widman
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Richard A Slivicki
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Jiwon Yi
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir. Boston, MA 02115
| | - Jochen K Lennerz
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114
| | - Jessica L Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080
| | - Robert W Gereau
- Program in Neurosciences, Division of Biology and Biomedical Sciences, Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - William Renthal
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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4
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Hori S, Tateyama M, Shirai T, Kubo Y, Saitoh O. Two single-point mutations in Ankyrin Repeat one drastically change the threshold temperature of TRPV1. Nat Commun 2023; 14:2415. [PMID: 37169739 PMCID: PMC10175561 DOI: 10.1038/s41467-023-38051-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 04/13/2023] [Indexed: 05/13/2023] Open
Abstract
TRPV1 plays an important role in the thermosensory system; however, the mechanism controlling its heat activation property is not well understood. Here, we determine the heat activation properties of TRPV1 cloned from tailed amphibians, which prefer cooler environments, finding the threshold temperatures were approximately 10 °C lower compared with rat TRPV1 (rTRPV1). We find that two amino acid residues (Gln, Leu/Val) in the Ankyrin Repeat 1 (ANK1) region of the N-terminal domain are conserved among tailed amphibians and different from those (Arg, Lys) in rTRPV1. We observe the activation by heat in all urodelan TRPV1s is markedly elevated by substitution of these two amino acids. Conversely, reciprocal substitutions of rTRPV1 apparently lowers the high threshold temperature. Our studies demonstrate that tailed amphibians express TRPV1 with a reduced heat-activation threshold by substitution of two amino acid residues in the ANK1 region that likely contribute to cool-habitat selection.
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Affiliation(s)
- Shogo Hori
- Graduate School of Biosciences, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Michihiro Tateyama
- Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Tsuyoshi Shirai
- Graduate School of Biosciences, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Yoshihiro Kubo
- Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Osamu Saitoh
- Graduate School of Biosciences, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan.
- Genome Editing Research Institute, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan.
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5
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Hori S, Saitoh O. Decreased heat sensitivity of lungfish TRPV1 revealed by the heterologous expression system. Biochem Biophys Res Commun 2023; 647:16-22. [PMID: 36709668 DOI: 10.1016/j.bbrc.2023.01.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
In this study, we focused on TRPV1 of African lungfish, Protopterus annectens. During drought at high temperature, African lungfish can survive by undergoing into aestivation in mud cocoons. Therefore, lungfish is considered to have some specialized heat-sensor, TRPV1, for heat tolerance. Further, lungfish which shares similarities with fishes and amphibians, is one of important species for investigating the fish-tetrapod transition. Since fish TRPV1 and tetrapod TRPV1 have some differences, character of lungfish TRPV1 attracts attention. Here, we first cloned TRPV1 paralogue from lungfish, Protopterus annectens (lfTRPV1) and determined the chemical and thermal sensitivities of lfTRPV1 by two-electrode voltage clamp method using frog oocytes. We detected activation of lfTRPV1 by acid and 2-APB, but capsaicin-induced activation was not observed. The sensitivity to acid of lfTRPV1 was similar to that of rat TRPV1 (rTRPV1), but the 2-APB sensitivity of lfTRPV1 was relatively weaker than rTRPV1. Heat stimulation up to 44 °C did not activate lfTRPV1 and the heat-activation was not detected even on acid condition of pH6. This dramatically decreased heat-sensitivity of TRPV1 may contribute the heat tolerance of African lungfish. Moreover, this might be the property of ancient tetrapod-type TRPV1 gene.
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Affiliation(s)
- Shogo Hori
- Department of Animal Bio-Science, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama-shi, Shiga, 526-0829, Japan
| | - Osamu Saitoh
- Genome Editing Research Institute, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama-shi, Shiga, 526-0829, Japan.
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6
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York JM, Zakon HH. OUP accepted manuscript. Genome Biol Evol 2022; 14:6519823. [PMID: 35106545 PMCID: PMC8857925 DOI: 10.1093/gbe/evac009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2022] [Indexed: 11/14/2022] Open
Abstract
Animals rely on their sensory systems to inform them of ecologically relevant environmental variation. In the Southern Ocean, the thermal environment has remained between −1.9 and 5 °C for 15 Myr, yet we have no knowledge of how an Antarctic marine organism might sense their thermal habitat as we have yet to discover a thermosensitive ion channel that gates (opens/closes) below 10 °C. Here, we investigate the evolutionary dynamics of transient receptor potential (TRP) channels, which are the primary thermosensors in animals, within cryonotothenioid fishes—the dominant fish fauna of the Southern Ocean. We found cryonotothenioids have a similar complement of TRP channels as other teleosts (∼28 genes). Previous work has shown that thermosensitive gating in a given channel is species specific, and multiple channels act together to sense the thermal environment. Therefore, we combined evidence of changes in selective pressure, gene gain/loss dynamics, and the first sensory ganglion transcriptome in this clade to identify the best candidate TRP channels that might have a functional dynamic range relevant for frigid Antarctic temperatures. We concluded that TRPV1a, TRPA1b, and TRPM4 are the likeliest putative thermosensors, and found evidence of diversifying selection at sites across these proteins. We also put forward hypotheses for molecular mechanisms of other cryonotothenioid adaptations, such as reduced skeletal calcium deposition, sensing oxidative stress, and unusual magnesium homeostasis. By completing a comprehensive and unbiased survey of these genes, we lay the groundwork for functional characterization and answering long-standing thermodynamic questions of thermosensitive gating and protein adaptation to low temperatures.
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Affiliation(s)
- Julia M York
- Department of Integrative Biology, University of Texas at Austin, USA
- Corresponding author: E-mail:
| | - Harold H Zakon
- Department of Integrative Biology, University of Texas at Austin, USA
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7
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Takahashi S, Kurogi M, Saitoh O. The diversity in sensitivity of TRPA1 and TRPV1 of various animals to polyphenols. Biomed Res 2021; 42:43-51. [PMID: 33840685 DOI: 10.2220/biomedres.42.43] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The perception of tastes is sensed by the receptors that stimulate sensory cells. We previously reported that TRPA1 and TRPV1 channels expressed in the oral cavity of mammals, are activated by the auto-oxidized product of epigallocatechin gallate (oxiEGCG), a major astringent catechin in green tea. Here, we investigated and compared the sensitivity of TRPA1 and TRPV1 from various animals to astringent polyphenols. We selected three polyphenols, oxiEGCG, tannic acid and myricetin. HEK293T cells expressing TRPA1 or TRPV1 from mammal, bird, reptile, amphibian, and fish, were analyzed for their activation by the Ca2+-imaging. We found the apparent diversity in the polyphenol-sensitivity among various animals. Mammalian TRPs showed relatively higher sensitivity to polyphenols, and especially, human TRPA1 and TRPV1 could be activated by all of three polyphenols at 20 μM. Reptile TRP channels, however, were insensitive to any polyphenols examined. Moreover, the polyphenol-sensitivity of zebrafish TRPA1 and TRPV1 was quite different from that of medaka TRP channels. Since many polyphenols are present in plants and the sensing of polyphenols using TRP channels in the oral cavity might cause astringent taste, the observed diversity of the polyphenol-sensitivity of TRP channels might be involved in the divergence in the food habit of various animals.
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Affiliation(s)
- Sayuri Takahashi
- Department of Bio-Science, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology
| | - Mako Kurogi
- Department of Bio-Science, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology
| | - Osamu Saitoh
- Department of Bio-Science, Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology
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8
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Fischer MJM, Ciotu CI, Szallasi A. The Mysteries of Capsaicin-Sensitive Afferents. Front Physiol 2020; 11:554195. [PMID: 33391007 PMCID: PMC7772409 DOI: 10.3389/fphys.2020.554195] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
A fundamental subdivision of nociceptive sensory neurons is named after their unique sensitivity to capsaicin, the pungent ingredient in hot chili peppers: these are the capsaicin-sensitive afferents. The initial excitation by capsaicin of these neurons manifested as burning pain sensation is followed by a lasting refractory state, traditionally referred to as "capsaicin desensitization," during which the previously excited neurons are unresponsive not only to capsaicin but a variety of unrelated stimuli including noxious heat. The long sought-after capsaicin receptor, now known as TRPV1 (transient receptor potential cation channel, subfamily V member 1), was cloned more than two decades ago. The substantial reduction of the inflammatory phenotype of Trpv1 knockout mice has spurred extensive efforts in the pharmaceutical industry to develop small molecule TRPV1 antagonists. However, adverse effects, most importantly hyperthermia and burn injuries, have so far prevented any compounds from progressing beyond Phase 2. There is increasing evidence that these limitations can be at least partially overcome by approaches outside of the mainstream pharmaceutical development, providing novel therapeutic options through TRPV1. Although ablation of the whole TRPV1-expressing nerve population by high dose capsaicin, or more selectively by intersectional genetics, has allowed researchers to investigate the functions of capsaicin-sensitive afferents in health and disease, several "mysteries" remain unsolved to date, including the molecular underpinnings of "capsaicin desensitization," and the exact role these nerves play in thermoregulation and heat sensation. This review tries to shed some light on these capsaicin mechanisms.
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Affiliation(s)
- Michael J. M. Fischer
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Cosmin I. Ciotu
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Arpad Szallasi
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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