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Baxter BD, Larson ED, Merle L, Feinstein P, Polese AG, Bubak AN, Niemeyer CS, Hassell J, Shepherd D, Ramakrishnan VR, Nagel MA, Restrepo D. Transcriptional profiling reveals potential involvement of microvillous TRPM5-expressing cells in viral infection of the olfactory epithelium. BMC Genomics 2021; 22:224. [PMID: 33781205 PMCID: PMC8007386 DOI: 10.1186/s12864-021-07528-y] [Citation(s) in RCA: 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: 06/08/2020] [Accepted: 03/12/2021] [Indexed: 02/07/2023] Open
Abstract
Background Understanding viral infection of the olfactory epithelium is essential because the olfactory nerve is an important route of entry for viruses to the central nervous system. Specialized chemosensory epithelial cells that express the transient receptor potential cation channel subfamily M member 5 (TRPM5) are found throughout the airways and intestinal epithelium and are involved in responses to viral infection. Results Herein we performed deep transcriptional profiling of olfactory epithelial cells sorted by flow cytometry based on the expression of mCherry as a marker for olfactory sensory neurons and for eGFP in OMP-H2B::mCherry/TRPM5-eGFP transgenic mice (Mus musculus). We find profuse expression of transcripts involved in inflammation, immunity and viral infection in TRPM5-expressing microvillous cells compared to olfactory sensory neurons. Conclusion Our study provides new insights into a potential role for TRPM5-expressing microvillous cells in viral infection of the olfactory epithelium. We find that, as found for solitary chemosensory cells (SCCs) and brush cells in the airway epithelium, and for tuft cells in the intestine, the transcriptome of TRPM5-expressing microvillous cells indicates that they are likely involved in the inflammatory response elicited by viral infection of the olfactory epithelium. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07528-y.
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Affiliation(s)
- B Dnate' Baxter
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Eric D Larson
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Laetitia Merle
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Paul Feinstein
- The Graduate Center Biochemistry, Biology and CUNY-Neuroscience-Collaborative Programs and Biological Sciences Department, Hunter College, City University of New York, New York, NY, 10065, USA
| | - Arianna Gentile Polese
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Andrew N Bubak
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Christy S Niemeyer
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - James Hassell
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Doug Shepherd
- Department of Pharmacology, University of Colorado Anschutz Medical Campus and Center for Biological Physics and Department of Physics, Arizona State University, Tempe, USA
| | - Vijay R Ramakrishnan
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Maria A Nagel
- Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Diego Restrepo
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA. .,Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Baxter BD, Larson ED, Merle L, Feinstein P, Polese AG, Bubak AN, Niemeyer CS, Hassell J, Shepherd D, Ramakrishnan VR, Nagel MA, Restrepo D. Transcriptional profiling reveals potential involvement of microvillous TRPM5-expressing cells in viral infection of the olfactory epithelium. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511400 DOI: 10.1101/2020.05.14.096016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Understanding viral infection of the olfactory epithelium is essential because the olfactory nerve is an important route of entry for viruses to the central nervous system. Specialized chemosensory epithelial cells that express the transient receptor potential cation channel subfamily M member 5 (TRPM5) are found throughout the airways and intestinal epithelium and are involved in responses to viral infection. Results Herein we performed deep transcriptional profiling of olfactory epithelial cells sorted by flow cytometry based on the expression of mCherry as a marker for olfactory sensory neurons and for eGFP in OMP-H2B::mCherry/TRPM5-eGFP transgenic mice ( Mus musculus ). We find profuse expression of transcripts involved in inflammation, immunity and viral infection in TRPM5-expressing microvillous cells. Conclusion Our study provides new insights into a potential role for TRPM5-expressing microvillous cells in viral infection of the olfactory epithelium. We find that, as found for solitary chemosensory cells (SCCs) and brush cells in the airway epithelium, and for tuft cells in the intestine, the transcriptome of TRPM5-expressing microvillous cells indicates that they are likely involved in the inflammatory response elicited by viral infection of the olfactory epithelium.
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Vennekens R, Mesuere M, Philippaert K. TRPM5 in the battle against diabetes and obesity. Acta Physiol (Oxf) 2018; 222. [PMID: 28834354 DOI: 10.1111/apha.12949] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/06/2017] [Accepted: 08/09/2017] [Indexed: 12/22/2022]
Abstract
TRPM5 is a non-selective monovalent cation channel activated by increases in intracellular Ca2+ . It has a distinct expression pattern: expression is detected in chemosensitive tissues from solitary chemosensory cells to the taste receptor cells and in pancreatic β-cells. The role of TRPM5 has been investigated with the use of knockout mouse models. Trpm5-/- mice have a lack of type II taste perception and show reduced glucose-induced insulin secretion. Expression levels of TRPM5 are reduced in obese, leptin-signalling-deficient mice, and mutations in TRPM5 have been associated with type II diabetes and metabolic syndrome. In this review, we aim to give an overview of the activation, selectivity, modulation and physiological roles of TRPM5.
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Affiliation(s)
- R. Vennekens
- VIB Center for Brain & Disease Research; Leuven Belgium
- Laboratory of Ion Channel Research; TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine; KU Leuven, Leuven Belgium
| | - M. Mesuere
- VIB Center for Brain & Disease Research; Leuven Belgium
- Laboratory of Ion Channel Research; TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine; KU Leuven, Leuven Belgium
| | - K. Philippaert
- VIB Center for Brain & Disease Research; Leuven Belgium
- Laboratory of Ion Channel Research; TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine; KU Leuven, Leuven Belgium
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Trpm5 expression in the olfactory epithelium. Mol Cell Neurosci 2017; 80:75-88. [PMID: 28188885 DOI: 10.1016/j.mcn.2017.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/02/2017] [Accepted: 02/05/2017] [Indexed: 11/20/2022] Open
Abstract
The Ca2+-activated monovalent cation channel Trpm5 is a key element in chemotransduction of taste receptor cells of the tongue, but the extent to which Trpm5 channels are expressed in olfactory sensory neurons (OSNs) of the main olfactory epithelium (MOE) of adult mice as part of a specific pheromonal detection system is debated. Here, we used a novel Trpm5-IRES-Cre knockin strain to drive Cre recombinase expression, employed previously validated Trpm5 antibodies, performed in situ hybridization experiments to localize Trpm5 RNA, and searched extensively for Trpm5 splice variants in genetically-labeled, Trpm5-expressing MOE cells. In contrast to previous reports, we find no evidence for the existence in adult mouse OSNs of the classical Trpm5 channel known from taste cells. We show that Trpm5-expressing adult OSNs express a novel Trpm5 splice variant, Trpm5-9, that is unlikely to form a functional cation channel by itself. We also demonstrate that Trpm5 is transiently expressed in a subpopulation of mature OSNs in the embryonic olfactory epithelium, indicating that Trpm5 channels could play a specific role in utero during a narrow developmental time window. Ca2+ imaging with GCaMP3 under the control of the Trpm5-IRES-Cre allele using a newly developed MOE wholemount preparation of the adult olfactory epithelium reveals that Trpm5-GCaMP3 OSNs comprise a heterogeneous group of sensory neurons many of which can detect general odorants. Together, these studies are essential for understanding the role of transient receptor potential channels in mammalian olfaction.
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Parrilla M, Chang I, Degl'Innocenti A, Omura M. Expression of homeobox genes in the mouse olfactory epithelium. J Comp Neurol 2016; 524:2713-39. [PMID: 27243442 DOI: 10.1002/cne.24051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 12/16/2015] [Accepted: 05/25/2016] [Indexed: 01/22/2023]
Abstract
Homeobox genes constitute a large family of genes widely studied because of their role in the establishment of the body pattern. However, they are also involved in many other events during development and adulthood. The main olfactory epithelium (MOE) is an excellent model to study neurogenesis in the adult nervous system. Analyses of homeobox genes during development show that some of these genes are involved in the formation and establishment of cell diversity in the MOE. Moreover, the mechanisms of expression of odorant receptors (ORs) constitute one of the biggest enigmas in the field. Analyses of OR promoters revealed the presence of homeodomain binding sites in their sequences. Here we characterize the expression patterns of a set of 49 homeobox genes in the MOE with in situ hybridization. We found that seven of them (Dlx3, Dlx5, Dlx6, Msx1, Meis1, Isl1, and Pitx1) are zonally expressed. The homeobox gene Emx1 is expressed in three guanylate cyclase(+) populations, two located in the MOE and the third one in an olfactory subsystem known as Grüneberg ganglion located at the entrance of the nasal cavity. The homeobox gene Tshz1 is expressed in a unique patchy pattern across the MOE. Our findings provide new insights to guide functional studies that aim to understand the complexity of transcription factor expression and gene regulation in the MOE. J. Comp. Neurol. 524:2713-2739, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marta Parrilla
- Max Planck Institut für Biophysik, Frankfurt am Main, Germany
| | - Isabelle Chang
- Max Planck Institut für Biophysik, Frankfurt am Main, Germany
| | - Andrea Degl'Innocenti
- Max Planck Institut für Biophysik, Frankfurt am Main, Germany.,Unità di Biologia Cellulare e dello Sviluppo, Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Masayo Omura
- Max Planck Institut für Biophysik, Frankfurt am Main, Germany
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Rolen SH, Salcedo E, Restrepo D, Finger TE. Differential localization of NT-3 and TrpM5 in glomeruli of the olfactory bulb of mice. J Comp Neurol 2014; 522:1929-40. [PMID: 24288162 DOI: 10.1002/cne.23512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/25/2013] [Accepted: 11/26/2013] [Indexed: 12/13/2022]
Abstract
Olfactory sensory neurons that express transient receptor potential channel M5 (TrpM5) or neurotrophin-3 (NT-3) project to defined clusters of glomeruli situated ventrally in the main olfactory bulb. Using genetically labeled mice, we investigated whether expression of NT-3-driven βgal and TrpM5-driven GFP marked overlapping sets of glomeruli and whether expression of these markers was coordinated. Our results indicate that these markers largely characterize independent sets of olfactory sensory neuron axons and glomeruli. Further, in glomeruli in which both TrpM5-GFP and NT-3-βgal labeled axons occur, they are expressed independently. The nature of staining for these two markers also differs within glomeruli. Within each labeled TrpM5-positive glomerulus, the level of TrpM5-GFP expression was similar throughout the glomerular neuropil. In contrast, NT-3-driven βgal expression levels are heterogeneous even within heavily labeled glomeruli. In addition, a population of very small TrpM5-GFP positive glomeruli is apparent while no similar populations of NT-3-βgal glomeruli are evident. Taken together, these data suggest that TrpM5 and NT-3 characterize two largely independent receptor populations both conveying odorant information to the ventral olfactory bulb.
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Affiliation(s)
- S H Rolen
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045
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Zhang E, Liao P. Brain transient receptor potential channels and stroke. J Neurosci Res 2014; 93:1165-83. [PMID: 25502473 DOI: 10.1002/jnr.23529] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/10/2014] [Accepted: 11/04/2014] [Indexed: 02/06/2023]
Abstract
Transient receptor potential (TRP) channels have been increasingly implicated in the pathological mechanisms of CNS disorders. TRP expression has been detected in neurons, astrocytes, oligodendrocytes, microglia, and ependymal cells as well as in the cerebral vascular endothelium and smooth muscle. In stroke, TRPC3/4/6, TRPM2/4/7, and TRPV1/3/4 channels have been found to participate in ischemia-induced cell death, whereas other TRP channels, in particular those expressed in nonneuronal cells, have been less well studied. This review summarizes the current knowledge on the expression and functions of the TRP channels in various cell types in the brain and our current understanding of TRP channels in stroke pathophysiology. In an aging society, the occurrence of stroke is expected to increase steadily, and there is an urgent requirement to improve the current stroke management strategy. Therefore, elucidating the roles of TRP channels in stroke could shed light on the development of novel therapeutic strategies and ultimately improve stroke outcome.
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Affiliation(s)
- Eric Zhang
- Calcium Signalling Laboratory, National Neuroscience Institute, Singapore
| | - Ping Liao
- Calcium Signalling Laboratory, National Neuroscience Institute, Singapore.,Duke-NUS Graduate Medical School Singapore, Singapore
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Transduction for pheromones in the main olfactory epithelium is mediated by the Ca2+ -activated channel TRPM5. J Neurosci 2014; 34:3268-78. [PMID: 24573286 DOI: 10.1523/jneurosci.4903-13.2014] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Growing evidence suggests that the main olfactory epithelium contains a subset of olfactory sensory neurons (OSNs) responding to pheromones. One candidate subpopulation expresses the calcium activated cation channel TRPM5 (transient receptor potential channel M5). Using GFP driven by the TRPM5 promoter in mice, we show that this subpopulation responds to putative pheromones, urine, and major histocompatibility complex peptides, but not to regular odors or a pheromone detected by other species. In addition, this subpopulation of TRPM5-GFP+ OSNs uses novel transduction. In regular OSNs, odorants elicit activation of the cyclic nucleotide-gated (CNG) channel, leading to Ca2+ gating of Cl- channels; in TRPM5-GFP+ OSNs, the Ca2+ -activated Cl- ANO2 (anoctamin 2) channel is not expressed, and pheromones elicit activation of the CNG channel leading to Ca2+ gating of TRPM5. In conclusion, we show that OSNs expressing TRPM5 respond to pheromones, but not to regular odors through the opening of CNG channels leading to Ca2+ gating of TRPM5.
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9
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Transduction for pheromones in the main olfactory epithelium is mediated by the Ca2+ -activated channel TRPM5. J Neurosci 2014. [PMID: 24573286 DOI: 10.1523/jneurosci.4903‐13.2014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Growing evidence suggests that the main olfactory epithelium contains a subset of olfactory sensory neurons (OSNs) responding to pheromones. One candidate subpopulation expresses the calcium activated cation channel TRPM5 (transient receptor potential channel M5). Using GFP driven by the TRPM5 promoter in mice, we show that this subpopulation responds to putative pheromones, urine, and major histocompatibility complex peptides, but not to regular odors or a pheromone detected by other species. In addition, this subpopulation of TRPM5-GFP+ OSNs uses novel transduction. In regular OSNs, odorants elicit activation of the cyclic nucleotide-gated (CNG) channel, leading to Ca2+ gating of Cl- channels; in TRPM5-GFP+ OSNs, the Ca2+ -activated Cl- ANO2 (anoctamin 2) channel is not expressed, and pheromones elicit activation of the CNG channel leading to Ca2+ gating of TRPM5. In conclusion, we show that OSNs expressing TRPM5 respond to pheromones, but not to regular odors through the opening of CNG channels leading to Ca2+ gating of TRPM5.
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Abstract
The mammalian olfactory system has become an excellent model system to understand the function of transient receptor potential (TRP) channels within their native cellular and circuit environment. The discovery that the canonical TRP channel TRPC2 is highly expressed in sensory neurons of the vomeronasal organ (VNO) has led to major advances in our understanding of the cellular and molecular processes underlying signal transduction of pheromones and other molecular cues that play an essential role in the control of instinctive decisions and innate social behaviors. TRPC2 knockout mice provide a striking example that the loss of function of a single gene can cause severe alterations in a variety of social interactions including the display of aggression, social dominance, and sexual behaviors. There is mounting evidence that TRPC2 is not the only TRP channel expressed in cells of the olfactory system but that other TRP channel subtypes such as TRPC1, TRPC4, TRPC6, TRPM4, and TRPM5 could also play important functional roles in mammalian olfaction. Here, I review such findings and discuss future areas for investigation.
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Affiliation(s)
- Frank Zufall
- Department of Physiology and Center for Integrative Physiology and Molecular Medicine, University of Saarland School of Medicine, 66424, Homburg, Germany,
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