1
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Ordway AJ, Helt RN, Johnston RJ. Transcriptional priming and chromatin regulation during stochastic cell fate specification. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230046. [PMID: 38432315 PMCID: PMC10909510 DOI: 10.1098/rstb.2023.0046] [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: 08/21/2023] [Accepted: 01/19/2024] [Indexed: 03/05/2024] Open
Abstract
Stochastic cell fate specification, in which a cell chooses between two or more fates with a set probability, diversifies cell subtypes in development. Although this is a vital process across species, a common mechanism for these cell fate decisions remains elusive. This review examines two well-characterized stochastic cell fate decisions to identify commonalities between their developmental programmes. In the fly eye, two subtypes of R7 photoreceptors are specified by the stochastic ON/OFF expression of a transcription factor, spineless. In the mouse olfactory system, olfactory sensory neurons (OSNs) randomly select to express one copy of an olfactory receptor (OR) gene out of a pool of 2800 alleles. Despite the differences in these sensory systems, both stochastic fate choices rely on the dynamic interplay between transcriptional priming, chromatin regulation and terminal gene expression. The coupling of transcription and chromatin modifications primes gene loci in undifferentiated neurons, enabling later expression during terminal differentiation. Here, we compare these mechanisms, examine broader implications for gene regulation during development and posit key challenges moving forward. This article is part of a discussion meeting issue 'Causes and consequences of stochastic processes in development and disease'.
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Affiliation(s)
- Alison J. Ordway
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Rina N. Helt
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Robert J. Johnston
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
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2
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Yusuf N, Monahan K. Epigenetic programming of stochastic olfactory receptor choice. Genesis 2024; 62:e23593. [PMID: 38562011 PMCID: PMC11003729 DOI: 10.1002/dvg.23593] [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: 11/27/2023] [Revised: 03/01/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
The mammalian sense of smell relies upon a vast array of receptor proteins to detect odorant compounds present in the environment. The proper deployment of these receptor proteins in olfactory sensory neurons is orchestrated by a suite of epigenetic processes that remodel the olfactory genes in differentiating neuronal progenitors. The goal of this review is to elucidate the central role of gene regulatory processes acting in neuronal progenitors of olfactory sensory neurons that lead to a singular expression of an odorant receptor in mature olfactory sensory neurons. We begin by describing the principal features of odorant receptor gene expression in mature olfactory sensory neurons. Next, we delineate our current understanding of how these features emerge from multiple gene regulatory mechanisms acting in neuronal progenitors. Finally, we close by discussing the key gaps in our understanding of how these regulatory mechanisms work and how they interact with each other over the course of differentiation.
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Affiliation(s)
- Nusrath Yusuf
- Division of Life Sciences-Molecular Biology and Biochemistry Department, Rutgers University-New Brunswick, New Brunswick, New Jersey, USA
| | - Kevin Monahan
- Division of Life Sciences-Molecular Biology and Biochemistry Department, Rutgers University-New Brunswick, New Brunswick, New Jersey, USA
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3
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Raja R, Dumontier E, Phen A, Cloutier JF. Insertion of a neomycin selection cassette in the Amigo1 locus alters gene expression in the olfactory epithelium leading to region-specific defects in olfactory receptor neuron development. Genesis 2024; 62:e23594. [PMID: 38590146 DOI: 10.1002/dvg.23594] [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: 12/04/2023] [Revised: 03/08/2024] [Accepted: 03/18/2024] [Indexed: 04/10/2024]
Abstract
During development of the nervous system, neurons connect to one another in a precisely organized manner. Sensory systems provide a good example of this organization, whereby the composition of the outside world is represented in the brain by neuronal maps. Establishing correct patterns of neural circuitry is crucial, as inaccurate map formation can lead to severe disruptions in sensory processing. In rodents, olfactory stimuli modulate a wide variety of behaviors essential for survival. The formation of the olfactory glomerular map is dependent on molecular cues that guide olfactory receptor neuron axons to broad regions of the olfactory bulb and on cell adhesion molecules that promote axonal sorting into specific synaptic units in this structure. Here, we demonstrate that the cell adhesion molecule Amigo1 is expressed in a subpopulation of olfactory receptor neurons, and we investigate its role in the precise targeting of olfactory receptor neuron axons to the olfactory bulb using a genetic loss-of-function approach in mice. While ablation of Amigo1 did not lead to alterations in olfactory sensory neuron axonal targeting, our experiments revealed that the presence of a neomycin resistance selection cassette in the Amigo1 locus can lead to off-target effects that are not due to loss of Amigo1 expression, including unexpected altered gene expression in olfactory receptor neurons and reduced glomerular size in the ventral region of the olfactory bulb. Our results demonstrate that insertion of a neomycin selection cassette into the mouse genome can have specific deleterious effects on the development of the olfactory system and highlight the importance of removing antibiotic resistance cassettes from genetic loss-of-function mouse models when studying olfactory system development.
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Affiliation(s)
- Reesha Raja
- The Neuro (Montreal Neurological Institute-Hospital), Montréal, Québec, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
| | - Emilie Dumontier
- The Neuro (Montreal Neurological Institute-Hospital), Montréal, Québec, Canada
| | - Alina Phen
- The Neuro (Montreal Neurological Institute-Hospital), Montréal, Québec, Canada
| | - Jean-François Cloutier
- The Neuro (Montreal Neurological Institute-Hospital), Montréal, Québec, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada
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4
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Hirota J. Molecular mechanisms of differentiation and class choice of olfactory sensory neurons. Genesis 2024; 62:e23587. [PMID: 38454646 DOI: 10.1002/dvg.23587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/10/2024] [Accepted: 01/29/2024] [Indexed: 03/09/2024]
Abstract
The sense of smell is intricately linked to essential animal behaviors necessary for individual survival and species preservation. During vertebrate evolution, odorant receptors (ORs), responsible for detecting odor molecules, have evolved to adapt to changing environments, transitioning from aquatic to terrestrial habitats and accommodating increasing complex chemical environments. These evolutionary pressures have given rise to the largest gene family in vertebrate genomes. Vertebrate ORs are phylogenetically divided into two major classes; class I and class II. Class I OR genes, initially identified in fish and frog, have persisted across vertebrate species. On the other hand, class II OR genes are unique to terrestrial animals, accounting for ~90% of mammalian OR genes. In mice, each olfactory sensory neuron (OSN) expresses a single functional allele of a single OR gene from either the class I or class II OR repertoire. This one neuron-one receptor rule is established through two sequential steps: specification of OR class and subsequent exclusive OR expression from the corresponding OR class. Consequently, OSNs acquire diverse neuronal identities during the process of OSN differentiation, enabling animals to detect a wide array of odor molecules. This review provides an overview of the OSN differentiation process through which OSN diversity is achieved, primarily using the mouse as a model animal.
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Affiliation(s)
- Junji Hirota
- Department of Life Science and Technology, Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Center for Integrative Biosciences, Tokyo Institute of Technology, Yokohama, Japan
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5
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Fang A, Yu CR. Activity-dependent formation of the topographic map and the critical period in the development of mammalian olfactory system. Genesis 2024; 62:e23586. [PMID: 38593162 PMCID: PMC11003738 DOI: 10.1002/dvg.23586] [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: 12/05/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 04/11/2024]
Abstract
Neural activity influences every aspect of nervous system development. In olfactory systems, sensory neurons expressing the same odorant receptor project their axons to stereotypically positioned glomeruli, forming a spatial map of odorant receptors in the olfactory bulb. As individual odors activate unique combinations of glomeruli, this map forms the basis for encoding olfactory information. The establishment of this stereotypical olfactory map requires coordinated regulation of axon guidance molecules instructed by spontaneous activity. Recent studies show that sensory experiences also modify innervation patterns in the olfactory bulb, especially during a critical period of the olfactory system development. This review examines evidence in the field to suggest potential mechanisms by which various aspects of neural activity regulate axon targeting. We also discuss the precise functions served by neural plasticity during the critical period.
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Affiliation(s)
- Ai Fang
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - C. Ron Yu
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Cell Biology and Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
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6
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Park SJ, Greer PL, Lee N. From odor to oncology: non-canonical odorant receptors in cancer. Oncogene 2024; 43:304-318. [PMID: 38087050 DOI: 10.1038/s41388-023-02908-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/16/2023] [Accepted: 11/23/2023] [Indexed: 01/31/2024]
Abstract
Odorant receptors, traditionally associated with olfaction as chemoreceptors, have been increasingly recognized for their presence and diverse functions in various non-nasal tissues throughout the body. Beyond their roles in sensory perception, emerging evidence suggests a compelling interplay between odorant receptors and cancer progression as well. Alongside the canonical GPCR odorant receptors, dysregulation of non-canonical odorant receptors such as trace amine-associated receptors (TAARs), formyl peptide receptors (FPRs), and membrane-spanning 4A family (MS4As) has been observed in various cancer types, suggesting their contributions to cancer progression. The roles of these non-canonical chemoreceptors in cancer are complex, with some receptors promoting tumorigenesis and others acting as tumor-suppressing factors upon activation, depending on the cancer type. These findings shed light on the potential of non-canonical odorant receptors as therapeutic targets and prognostic markers in cancer, inviting further exploration to unravel their precise mechanisms of action and implications in cancer biology. In this review, we provide a comprehensive overview of the intricate relationships between these chemoreceptors and various types of cancer, potentially paving the way for innovative odor-based therapeutics. Ultimately, this review discusses the potential development of novel therapeutic strategies targeting these non-canonical chemoreceptors.
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Affiliation(s)
- Sung Jin Park
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Paul L Greer
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Namgyu Lee
- Department of Biomedical Science and Engineering, Dankook University, Cheonan, 31116, Republic of Korea.
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7
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Bashkirova EV, Klimpert N, Monahan K, Campbell CE, Osinski J, Tan L, Schieren I, Pourmorady A, Stecky B, Barnea G, Xie XS, Abdus-Saboor I, Shykind BM, Marlin BJ, Gronostajski RM, Fleischmann A, Lomvardas S. Opposing, spatially-determined epigenetic forces impose restrictions on stochastic olfactory receptor choice. eLife 2023; 12:RP87445. [PMID: 38108811 PMCID: PMC10727497 DOI: 10.7554/elife.87445] [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] [Indexed: 12/19/2023] Open
Abstract
Olfactory receptor (OR) choice represents an example of genetically hardwired stochasticity, where every olfactory neuron expresses one out of ~2000 OR alleles in the mouse genome in a probabilistic, yet stereotypic fashion. Here, we propose that topographic restrictions in OR expression are established in neuronal progenitors by two opposing forces: polygenic transcription and genomic silencing, both of which are influenced by dorsoventral gradients of transcription factors NFIA, B, and X. Polygenic transcription of OR genes may define spatially constrained OR repertoires, among which one OR allele is selected for singular expression later in development. Heterochromatin assembly and genomic compartmentalization of OR alleles also vary across the axes of the olfactory epithelium and may preferentially eliminate ectopically expressed ORs with more dorsal expression destinations from this 'privileged' repertoire. Our experiments identify early transcription as a potential 'epigenetic' contributor to future developmental patterning and reveal how two spatially responsive probabilistic processes may act in concert to establish deterministic, precise, and reproducible territories of stochastic gene expression.
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Affiliation(s)
- Elizaveta V Bashkirova
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, Columbia UniversityNew YorkUnited States
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Nell Klimpert
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown UniversityProvidenceUnited States
| | - Kevin Monahan
- Department of Biochemistry and Molecular Biology, Rutgers UniversityNewarkUnited States
| | - Christine E Campbell
- Department of Biochemistry, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life SciencesBuffaloUnited States
- Genetics, Genomics, and Bioinformatics Graduate Program, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life SciencesBuffaloUnited States
| | - Jason Osinski
- Department of Biochemistry, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life SciencesBuffaloUnited States
- Genetics, Genomics, and Bioinformatics Graduate Program, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life SciencesBuffaloUnited States
| | - Longzhi Tan
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Ira Schieren
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Ariel Pourmorady
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, Columbia UniversityNew YorkUnited States
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Beka Stecky
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Gilad Barnea
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown UniversityProvidenceUnited States
| | - Xiaoliang Sunney Xie
- Beijing Innovation Center for Genomics, Peking UniversityBeijingChina
- Biomedical Pioneering Innovation Center, Peking UniversityBeijingChina
| | - Ishmail Abdus-Saboor
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Benjamin M Shykind
- Prevail Therapeutics- a wholly-owned subsidiary of Eli Lilly and CompanyNew YorkUnited States
| | - Bianca J Marlin
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Richard M Gronostajski
- Department of Biochemistry, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life SciencesBuffaloUnited States
- Genetics, Genomics, and Bioinformatics Graduate Program, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life SciencesBuffaloUnited States
| | - Alexander Fleischmann
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown UniversityProvidenceUnited States
| | - Stavros Lomvardas
- Zuckerman Mind, Brain, and Behavior Institute, Columbia UniversityNew YorkUnited States
- Department of Biochemistry and Molecular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, Columbia UniversityNew YorkUnited States
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8
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Brewer AA, Barton B. Cortical field maps across human sensory cortex. Front Comput Neurosci 2023; 17:1232005. [PMID: 38164408 PMCID: PMC10758003 DOI: 10.3389/fncom.2023.1232005] [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] [Received: 06/03/2023] [Accepted: 11/07/2023] [Indexed: 01/03/2024] Open
Abstract
Cortical processing pathways for sensory information in the mammalian brain tend to be organized into topographical representations that encode various fundamental sensory dimensions. Numerous laboratories have now shown how these representations are organized into numerous cortical field maps (CMFs) across visual and auditory cortex, with each CFM supporting a specialized computation or set of computations that underlie the associated perceptual behaviors. An individual CFM is defined by two orthogonal topographical gradients that reflect two essential aspects of feature space for that sense. Multiple adjacent CFMs are then organized across visual and auditory cortex into macrostructural patterns termed cloverleaf clusters. CFMs within cloverleaf clusters are thought to share properties such as receptive field distribution, cortical magnification, and processing specialization. Recent measurements point to the likely existence of CFMs in the other senses, as well, with topographical representations of at least one sensory dimension demonstrated in somatosensory, gustatory, and possibly olfactory cortical pathways. Here we discuss the evidence for CFM and cloverleaf cluster organization across human sensory cortex as well as approaches used to identify such organizational patterns. Knowledge of how these topographical representations are organized across cortex provides us with insight into how our conscious perceptions are created from our basic sensory inputs. In addition, studying how these representations change during development, trauma, and disease serves as an important tool for developing improvements in clinical therapies and rehabilitation for sensory deficits.
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Affiliation(s)
- Alyssa A. Brewer
- mindSPACE Laboratory, Departments of Cognitive Sciences and Language Science (by Courtesy), Center for Hearing Research, University of California, Irvine, Irvine, CA, United States
| | - Brian Barton
- mindSPACE Laboratory, Department of Cognitive Sciences, University of California, Irvine, Irvine, CA, United States
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9
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Bashkirova EV, Klimpert N, Monahan K, Campbell CE, Osinski JM, Tan L, Schieren I, Pourmorady A, Stecky B, Barnea G, Xie XS, Abdus-Saboor I, Shykind B, Jones-Marlin B, Gronostajski RM, Fleischmann A, Lomvardas S. Opposing, spatially-determined epigenetic forces impose restrictions on stochastic olfactory receptor choice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532726. [PMID: 36993168 PMCID: PMC10055043 DOI: 10.1101/2023.03.15.532726] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Olfactory receptor (OR) choice represents an example of genetically hardwired stochasticity, where every olfactory neuron expresses one out of ~2000 OR alleles in a probabilistic, yet stereotypic fashion. Here, we propose that topographic restrictions in OR expression are established in neuronal progenitors by two opposing forces: polygenic transcription and genomic silencing, both of which are influenced by dorsoventral gradients of transcription factors NFIA, B, and X. Polygenic transcription of OR genes may define spatially constrained OR repertoires, among which one OR allele is selected for singular expression later in development. Heterochromatin assembly and genomic compartmentalization of OR alleles also vary across the axes of the olfactory epithelium and may preferentially eliminate ectopically expressed ORs with more dorsal expression destinations from this "privileged" repertoire. Our experiments identify early transcription as a potential "epigenetic" contributor to future developmental patterning and reveal how two spatially responsive probabilistic processes may act in concert to establish deterministic, precise, and reproducible territories of stochastic gene expression.
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Affiliation(s)
- Elizaveta V Bashkirova
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, Columbia University, New York, NY, 10032, USA
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
| | - Nell Klimpert
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, USA
| | - Kevin Monahan
- Department of Biochemistry and Molecular Biology, Rutgers University, NJ, USA
| | - Christine E Campbell
- Department of Biochemistry, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
- Genetics, Genomics, and Bioinformatics Graduate Program, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
| | - Jason M Osinski
- Department of Biochemistry, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
- Genetics, Genomics, and Bioinformatics Graduate Program, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
| | - Longzhi Tan
- Department of Bioengineering, Stanford University, CA, USA
| | - Ira Schieren
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
| | - Ariel Pourmorady
- Integrated Program in Cellular, Molecular and Biomedical Studies, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, Columbia University, New York, NY, 10032, USA
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
| | - Beka Stecky
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
| | - Gilad Barnea
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, USA
| | - X Sunnie Xie
- Beijing Innovation Center for Genomics, Peking University, Beijing, China
- Biomedical Pioneering Innovation Center, Peking University, Beijing, China
| | - Ishmail Abdus-Saboor
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
| | - Benjamin Shykind
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, USA
| | - Bianca Jones-Marlin
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
| | - Richard M Gronostajski
- Department of Biochemistry, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
- Genetics, Genomics, and Bioinformatics Graduate Program, University at Buffalo and New York State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY, USA
| | - Alexander Fleischmann
- Department of Neuroscience, Division of Biology and Medicine and Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, USA
| | - Stavros Lomvardas
- Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY, 10027, USA
- Department of Biochemistry and Molecular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, Columbia University, New York, NY, 10032, USA
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10
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Zhu KW, Matsunami H. Target-Captured mRNA from Murine Olfactory Bulb. Methods Mol Biol 2023; 2710:149-170. [PMID: 37688731 DOI: 10.1007/978-1-0716-3425-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2023]
Abstract
The external world is perceived via sensory receptors arranged in highly organized systems according to functional strategies, which in turn reflect features of critical importance to both the sense and the animal. Thus describing the receptor organization and functional strategies of olfaction, the sense of smell, is crucial for a concrete understanding of the fundamental principles of the system's architecture. Sensory processing in olfactory systems is organized across olfactory bulb (OB) glomeruli, wherein axons of peripheral sensory neurons expressing the same olfactory receptor (OR) co-terminate to transmit receptor-specific activity to mitral/tufted cells, projection neurons in the olfactory bulb. Understanding how receptors map to glomeruli is therefore critical to understanding olfaction.Here we describe a method to enrich low-abundant OR mRNAs from the mouse OB for spatial transcriptomics to generate high-throughput mapping of receptors to glomeruli [2]. Our method combines sequential sectioning along the anteroposterior, dorsoventral, and mediolateral axes with target capture enrichment sequencing to overcome low-abundance target expression. This strategy spatially mapped 86% of olfactory receptors across the olfactory bulb and uncovered a relationship between olfactory receptor sequence and glomerular position.
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Affiliation(s)
- Kevin W Zhu
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
- Department of Neurobiology, Duke Institute for Brain Sciences, Durham, NC, USA
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11
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Moussa EA, Makhlouf M, Mathew LS, Saraiva LR. Genome-Wide RNA Tomography in the Mouse Whole Olfactory Mucosa. Methods Mol Biol 2023; 2710:19-30. [PMID: 37688721 DOI: 10.1007/978-1-0716-3425-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2023]
Abstract
Spatial transcriptomics allows for the genome-wide profiling of topographic gene expression patterns within a tissue of interest. Here, we describe our methodology to generate high-quality RNA-seq libraries from cryosections from fresh frozen mouse whole olfactory mucosae. This methodology can be extended to virtually any vertebrate organ or tissue sample.
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Affiliation(s)
| | | | | | - Luis R Saraiva
- Sidra Medicine, Doha, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- Monell Chemical Senses Center, Philadelphia, PA, USA
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12
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Dang P, Barnes DT, Cheng RP, Xu A, Moon YJ, Kodukula SS, Raper JA. Netrins and Netrin Receptors are Essential for Normal Targeting of Sensory Axons in the Zebrafish Olfactory Bulb. Neuroscience 2023; 508:19-29. [PMID: 35940453 PMCID: PMC9839495 DOI: 10.1016/j.neuroscience.2022.08.004] [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: 04/28/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 01/17/2023]
Abstract
Olfactory sensory neurons that express related odorant receptors specifically target large identifiable neuropils called protoglomeruli when they first reach the olfactory bulb in the zebrafish. This crude odorant receptor-related mapping is further refined as odorant receptor-specific glomeruli segregate from protoglomeruli later in development. Netrins are a prominent class of axon guidance molecules whose contribution to olfactory circuit formation is poorly studied. Morpholino knock down experiments have suggested that Netrin/Dcc signaling is involved in normal protoglomerular targeting. Here we extend these findings with more detailed characterization and modeling of netrin expression, and by examining protoglomerular targeting in mutant lines fornetrin1a (ntn1a), netrin1b (ntn1b), and their receptorsunc5b,dcc, andneo1a. We confirm thatntn1a,ntn1b, anddccare required for normal protoglomerular guidance of a subset of olfactory sensory neurons that are labeled with the Tg(or111-7:IRES:Gal4) transgene. We also observe errors in the targeting of these axons inunc5bmutants, but not inneo1a mutants. Our findings are consistent with ntn1a andntn1bacting primarily as attractants for olfactory sensory neurons targeting the central zone protoglomerulus.
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Affiliation(s)
- Puneet Dang
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Daniel T Barnes
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ryan P Cheng
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Alison Xu
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Yoon Ji Moon
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Sai Sripad Kodukula
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Jonathan A Raper
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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13
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Hussainy M, Korsching SI, Tresch A. Pseudotime analysis reveals novel regulatory factors for multigenic onset and monogenic transition of odorant receptor expression. Sci Rep 2022; 12:16183. [PMID: 36171231 PMCID: PMC9519747 DOI: 10.1038/s41598-022-20106-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 09/08/2022] [Indexed: 12/02/2022] Open
Abstract
During their maturation from horizontal basal stem cells, olfactory sensory neurons (OSNs) are known to select exactly one out of hundreds of olfactory receptors (ORs) and express it on their surface, a process called monogenic selection. Monogenic expression is preceded by a multigenic phase during which several OR genes are expressed in a single OSN. Here, we perform pseudotime analysis of a single cell RNA-Seq dataset of murine olfactory epithelium to precisely align the multigenic and monogenic expression phases with the cell types occurring during OSN differentiation. In combination with motif analysis of OR gene cluster-associated enhancer regions, we identify known and novel transcription (co-)factors (Ebf1, Lhx2, Ldb1, Fos and Ssbp2) and chromatin remodelers (Kdm1a, Eed and Zmynd8) associated with OR expression. The inferred temporal order of their activity suggests novel mechanisms contributing to multigenic OR expression and monogenic selection.
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Affiliation(s)
- Mohammad Hussainy
- Institute of Medical Statistics and Computational Biology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Institute of Genetics, Faculty of Mathematics and Natural Sciences, University of Cologne, Cologne, Germany
| | - Sigrun I Korsching
- Institute of Genetics, Faculty of Mathematics and Natural Sciences, University of Cologne, Cologne, Germany
| | - Achim Tresch
- Institute of Medical Statistics and Computational Biology, Faculty of Medicine, University of Cologne, Cologne, Germany. .,Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany. .,Center for Data and Simulation Science, University of Cologne, Cologne, Germany.
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14
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Kurihara S, Tei M, Hata J, Mori E, Fujioka M, Matsuwaki Y, Otori N, Kojima H, Okano HJ. MRI tractography reveals the human olfactory nerve map connecting the olfactory epithelium and olfactory bulb. Commun Biol 2022; 5:843. [PMID: 36068329 PMCID: PMC9448749 DOI: 10.1038/s42003-022-03794-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
The olfactory nerve map describes the topographical neural connections between the olfactory epithelium in the nasal cavity and the olfactory bulb. Previous studies have constructed the olfactory nerve maps of rodents using histological analyses or transgenic animal models to investigate olfactory nerve pathways. However, the human olfactory nerve map remains unknown. Here, we demonstrate that high-field magnetic resonance imaging and diffusion tensor tractography can be used to visualize olfactory sensory neurons while maintaining their three-dimensional structures. This technique allowed us to evaluate the olfactory sensory neuron projections from the nasal cavities to the olfactory bulbs and visualize the olfactory nerve maps of humans, marmosets and mice. The olfactory nerve maps revealed that the dorsal-ventral and medial-lateral axes were preserved between the olfactory epithelium and olfactory bulb in all three species. Further development of this technique might allow it to be used clinically to facilitate the diagnosis of olfactory dysfunction. Combined high-field MRI and DTI analyses in post-mortem mouse, marmoset, and human samples provide insight into the neural connections between nasal cavities and olfactory bulbs.
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Affiliation(s)
- Sho Kurihara
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan.
| | - Masayoshi Tei
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Junichi Hata
- Division of Regenerative Medicine, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan.,Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10 Higashi-Ogu Arakawa-ku, Tokyo, 116-8551, Japan
| | - Eri Mori
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Masato Fujioka
- Department of Molecular Genetics, Kitasato University School of Medicine, 1-15-1 Kitasato Minami-ku Sagamihara-shi, Kanagawa, 252-0373, Japan.,Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Yoshinori Matsuwaki
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Nobuyoshi Otori
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Hiromi Kojima
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Hirotaka James Okano
- Division of Regenerative Medicine, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan.
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15
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Zhu KW, Burton SD, Nagai MH, Silverman JD, de March CA, Wachowiak M, Matsunami H. Decoding the olfactory map through targeted transcriptomics links murine olfactory receptors to glomeruli. Nat Commun 2022; 13:5137. [PMID: 36050313 PMCID: PMC9437035 DOI: 10.1038/s41467-022-32267-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 07/21/2022] [Indexed: 12/12/2022] Open
Abstract
Sensory processing in olfactory systems is organized across olfactory bulb glomeruli, wherein axons of peripheral sensory neurons expressing the same olfactory receptor co-terminate to transmit receptor-specific activity to central neurons. Understanding how receptors map to glomeruli is therefore critical to understanding olfaction. High-throughput spatial transcriptomics is a rapidly advancing field, but low-abundance olfactory receptor expression within glomeruli has previously precluded high-throughput mapping of receptors to glomeruli in the mouse. Here we combined sequential sectioning along the anteroposterior, dorsoventral, and mediolateral axes with target capture enrichment sequencing to overcome low-abundance target expression. This strategy allowed us to spatially map 86% of olfactory receptors across the olfactory bulb and uncover a relationship between OR sequence and glomerular position.
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Affiliation(s)
- Kevin W Zhu
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Shawn D Burton
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT, 84112, USA
| | - Maira H Nagai
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Justin D Silverman
- College of Information Science and Technology, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Statistics, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Medicine, Pennsylvania State University, Hershey, PA, 17033, USA
- Institute for Computational and Data Science, Pennsylvania State University, University Park, PA, 16802, USA
| | - Claire A de March
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Matt Wachowiak
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT, 84112, USA.
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, 27710, USA.
- Duke Institute for Brain Sciences, Duke University, Durham, NC, 27710, USA.
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16
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Kowatschew D, Bozorg Nia S, Hassan S, Ustinova J, Weth F, Korsching SI. Spatial organization of olfactory receptor gene choice in the complete V1R-related ORA family of zebrafish. Sci Rep 2022; 12:14816. [PMID: 36045218 PMCID: PMC9433392 DOI: 10.1038/s41598-022-17900-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/02/2022] [Indexed: 11/12/2022] Open
Abstract
The vertebrate sense of smell employs four main receptor families for detection of odors, among them the V1R/ORA family, which is unusually small and highly conserved in teleost fish. Zebrafish possess just seven ORA receptors, enabling a comprehensive analysis of the expression patterns of the entire family. The olfactory organ of zebrafish is representative for teleosts, cup-shaped, with lamella covered with sensory epithelium protruding into the cup from a median raphe. We have performed quantitative in situ hybridization on complete series of horizontal cryostat sections of adult zebrafish olfactory organ, and have analysed the location of ora-expressing cells in three dimensions, radial diameter, laminar height, and height-within-the-organ. We report broadly overlapping, but distinctly different distributions for all ora genes, even for ora3a and ora3b, the most recent gene duplication. Preferred positions in different dimensions are independent of each other. This spatial logic is very similar to previous reports for the much larger families of odorant receptor (or) and V2R-related olfC genes in zebrafish. Preferred positions for ora genes tend to be more central and more apical than those we observed for these other two families, consistent with expression in non-canonical sensory neuron types.
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Affiliation(s)
- Daniel Kowatschew
- Institute of Genetics, Mathematical-Natural Sciences Faculty of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany
| | - Shahrzad Bozorg Nia
- Institute of Genetics, Mathematical-Natural Sciences Faculty of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany
| | - Shahzaib Hassan
- Institute of Genetics, Mathematical-Natural Sciences Faculty of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany
| | - Jana Ustinova
- Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, 76131, Karlsruhe, Germany
| | - Franco Weth
- Zoological Institute, Department of Cell- and Neurobiology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, 76131, Karlsruhe, Germany
| | - Sigrun I Korsching
- Institute of Genetics, Mathematical-Natural Sciences Faculty of the University at Cologne, Zülpicher Str. 47A, 50674, Cologne, Germany.
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17
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Voortman L, Anderson C, Urban E, Yuan L, Tran S, Neuhaus-Follini A, Derrick J, Gregor T, Johnston RJ. Temporally dynamic antagonism between transcription and chromatin compaction controls stochastic photoreceptor specification in flies. Dev Cell 2022; 57:1817-1832.e5. [PMID: 35835116 PMCID: PMC9378680 DOI: 10.1016/j.devcel.2022.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 05/09/2022] [Accepted: 06/20/2022] [Indexed: 01/12/2023]
Abstract
Stochastic mechanisms diversify cell fates during development. How cells randomly choose between two or more fates remains poorly understood. In the Drosophila eye, the random mosaic of two R7 photoreceptor subtypes is determined by expression of the transcription factor Spineless (Ss). We investigated how cis-regulatory elements and trans factors regulate nascent transcriptional activity and chromatin compaction at the ss gene locus during R7 development. The ss locus is in a compact state in undifferentiated cells. An early enhancer drives transcription in all R7 precursors, and the locus opens. In differentiating cells, transcription ceases and the ss locus stochastically remains open or compacts. In SsON R7s, ss is open and competent for activation by a late enhancer, whereas in SsOFF R7s, ss is compact, and repression prevents expression. Our results suggest that a temporally dynamic antagonism, in which transcription drives large-scale decompaction and then compaction represses transcription, controls stochastic fate specification.
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Affiliation(s)
- Lukas Voortman
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Caitlin Anderson
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Elizabeth Urban
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Luorongxin Yuan
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sang Tran
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | | | - Josh Derrick
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Thomas Gregor
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA; Joseph Henry Laboratories of Physics, the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Developmental and Stem Cell Biology, UMR3738, Institut Pasteur, 75015 Paris, France
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
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18
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Gaun V, Martens JR, Schwob JE. Lifespan of mature olfactory sensory neurons varies with location in the mouse olfactory epithelium and age of the animal. J Comp Neurol 2022; 530:2238-2251. [PMID: 35434783 PMCID: PMC9233066 DOI: 10.1002/cne.25330] [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: 11/03/2021] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 08/03/2023]
Abstract
The olfactory sensory neurons (OSNs) of the olfactory epithelium (OE) exhibit a remarkable regenerative capability, which protects the population against environmental insult and enables adjustment to new odors. The lifespan of OSNs is still open to question, with estimates ranging from 1 month to at least 1 year. However, the estimates come with some caveats, including low labeling efficiency and a focus solely on newborn neurons. We revisited the issue via the use of OMP-tTA; TetO-Cre; Rosa26-fl(stop)-Tdtomato (OMP-tTA;TdT) mice, which allowed us to selectively label ∼95% of the OMP(+) OSN population that reach maturity by a given time and, by switching to doxycycline chow, to "chase" this preexisting OSN population. Two loading protocols were used: conception to 2 months old and conception to 4.5 months old. Surviving OSNs were common up to 6 months chase time in both groups, but more neurons survived when loading for 4.5 months as compared with 2 months. A spatial difference was evident: higher percentages of OSNs survived in the dorsomedial OE as compared with ventrolateral and in posterior versus anterior OE regions. Finally, proliferation rates anticorrelated with the spatial differences in OSN survival; higher proliferation rates were observed ventrally. Together, these results demonstrate spatial and temporal differences in OSN survival, highlighting it as a dynamic system that can be studied for factors affecting neuronal survival.
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Affiliation(s)
- Vera Gaun
- Program in Cellular, Molecular and Developmental Biology, Graduate School of Biomedical Sciences and Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA
| | - Jeffrey R. Martens
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine and Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL
| | - James E. Schwob
- Program in Cellular, Molecular and Developmental Biology, Graduate School of Biomedical Sciences and Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA
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19
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Dorrego-Rivas A, Grubb MS. Developing and maintaining a nose-to-brain map of odorant identity. Open Biol 2022; 12:220053. [PMID: 35765817 PMCID: PMC9240688 DOI: 10.1098/rsob.220053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Olfactory sensory neurons (OSNs) in the olfactory epithelium of the nose transduce chemical odorant stimuli into electrical signals. These signals are then sent to the OSNs' target structure in the brain, the main olfactory bulb (OB), which performs the initial stages of sensory processing in olfaction. The projection of OSNs to the OB is highly organized in a chemospatial map, whereby axon terminals from OSNs expressing the same odorant receptor (OR) coalesce into individual spherical structures known as glomeruli. This nose-to-brain map of odorant identity is built from late embryonic development to early postnatal life, through a complex combination of genetically encoded, OR-dependent and activity-dependent mechanisms. It must then be actively maintained throughout adulthood as OSNs experience turnover due to external insult and ongoing neurogenesis. Our review describes and discusses these two distinct and crucial processes in olfaction, focusing on the known mechanisms that first establish and then maintain chemospatial order in the mammalian OSN-to-OB projection.
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Affiliation(s)
- Ana Dorrego-Rivas
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Matthew S. Grubb
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
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20
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Ruiz Tejada Segura ML, Abou Moussa E, Garabello E, Nakahara TS, Makhlouf M, Mathew LS, Wang L, Valle F, Huang SSY, Mainland JD, Caselle M, Osella M, Lorenz S, Reisert J, Logan DW, Malnic B, Scialdone A, Saraiva LR. A 3D transcriptomics atlas of the mouse nose sheds light on the anatomical logic of smell. Cell Rep 2022; 38:110547. [PMID: 35320714 PMCID: PMC8995392 DOI: 10.1016/j.celrep.2022.110547] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/26/2022] [Accepted: 03/01/2022] [Indexed: 12/26/2022] Open
Abstract
The sense of smell helps us navigate the environment, but its molecular architecture and underlying logic remain understudied. The spatial location of odorant receptor genes (Olfrs) in the nose is thought to be independent of the structural diversity of the odorants they detect. Using spatial transcriptomics, we create a genome-wide 3D atlas of the mouse olfactory mucosa (OM). Topographic maps of genes differentially expressed in space reveal that both Olfrs and non-Olfrs are distributed in a continuous and overlapping fashion over at least five broad zones in the OM. The spatial locations of Olfrs correlate with the mucus solubility of the odorants they recognize, providing direct evidence for the chromatographic theory of olfaction. This resource resolves the molecular architecture of the mouse OM and will inform future studies on mechanisms underlying Olfr gene choice, axonal pathfinding, patterning of the nervous system, and basic logic for the peripheral representation of smell.
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Affiliation(s)
- Mayra L Ruiz Tejada Segura
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany; Institute of Functional Epigenetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany; Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | | | - Elisa Garabello
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany; Physics Department, University of Turin and INFN, Via P. Giuria 1, 10125 Turin, Italy; Department of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Thiago S Nakahara
- Department of Biochemistry, University of São Paulo, São Paulo, Brazil
| | | | | | - Li Wang
- Sidra Medicine, P.O. Box 26999, Doha, Qatar
| | - Filippo Valle
- Physics Department, University of Turin and INFN, Via P. Giuria 1, 10125 Turin, Italy
| | | | - Joel D Mainland
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA; Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michele Caselle
- Physics Department, University of Turin and INFN, Via P. Giuria 1, 10125 Turin, Italy
| | - Matteo Osella
- Physics Department, University of Turin and INFN, Via P. Giuria 1, 10125 Turin, Italy
| | - Stephan Lorenz
- Sidra Medicine, P.O. Box 26999, Doha, Qatar; Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Johannes Reisert
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Darren W Logan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Bettina Malnic
- Department of Biochemistry, University of São Paulo, São Paulo, Brazil
| | - Antonio Scialdone
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany; Institute of Functional Epigenetics, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany; Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
| | - Luis R Saraiva
- Sidra Medicine, P.O. Box 26999, Doha, Qatar; Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA; College of Health and Life Sciences, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar.
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21
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Coppola DM. The sorption/chromatography hypothesis of olfactory discrimination: The rise, fall, and rebirth of a Phoenix. Bioessays 2022; 44:e2100263. [PMID: 34984707 DOI: 10.1002/bies.202100263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/09/2022]
Abstract
Herein, I discuss the enduring mystery of the receptor layout in the vertebrate olfactory system. Since the awarding of the 2004 Nobel Prize to Axel and Buck for their discovery of the gene family that encodes olfactory receptors, our field has enjoyed a golden era. Despite this Renaissance, an answer to one of the most fundamental questions for any sensory system-what is the anatomical logic of its receptor array?-eludes us, still, for olfaction! Indeed, the only widely debated hypothesis, finding its origins in the musing of another Nobel laureate Sir Edgar Adrian, has it that the vertebrate nose organizes its receptors according to the "sorptive" properties of their ligands. This idea, known as the "sorption" or "chromatography" hypothesis, enjoys considerable support despite being controversial. Here, I review the history of the hypothesis-its rises and falls-and discuss the latest data and future prospects for this perennial idea whose history I liken to the mythical Phoenix.
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Affiliation(s)
- David M Coppola
- Department of Biology, Randolph-Macon College, Ashland, Virginia, 23005, USA
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22
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Voortman L, Johnston RJ. Transcriptional repression in stochastic gene expression, patterning, and cell fate specification. Dev Biol 2022; 481:129-138. [PMID: 34688689 PMCID: PMC8665150 DOI: 10.1016/j.ydbio.2021.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 10/04/2021] [Accepted: 10/09/2021] [Indexed: 01/03/2023]
Abstract
Development is often driven by signaling and lineage-specific cues, yielding highly uniform and reproducible outcomes. Development also involves mechanisms that generate noise in gene expression and random patterns across tissues. Cells sometimes randomly choose between two or more cell fates in a mechanism called stochastic cell fate specification. This process diversifies cell types in otherwise homogenous tissues. Stochastic mechanisms have been extensively studied in prokaryotes where noisy gene activation plays a pivotal role in controlling cell fates. In eukaryotes, transcriptional repression stochastically limits gene expression to generate random patterns and specify cell fates. Here, we review our current understanding of repressive mechanisms that produce random patterns of gene expression and cell fates in flies, plants, mice, and humans.
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Affiliation(s)
- Lukas Voortman
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA
| | - Robert J Johnston
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA.
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23
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24
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Tsukahara T, Brann DH, Pashkovski SL, Guitchounts G, Bozza T, Datta SR. A transcriptional rheostat couples past activity to future sensory responses. Cell 2021; 184:6326-6343.e32. [PMID: 34879231 PMCID: PMC8758202 DOI: 10.1016/j.cell.2021.11.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 10/07/2021] [Accepted: 11/11/2021] [Indexed: 10/19/2022]
Abstract
Animals traversing different environments encounter both stable background stimuli and novel cues, which are thought to be detected by primary sensory neurons and then distinguished by downstream brain circuits. Here, we show that each of the ∼1,000 olfactory sensory neuron (OSN) subtypes in the mouse harbors a distinct transcriptome whose content is precisely determined by interactions between its odorant receptor and the environment. This transcriptional variation is systematically organized to support sensory adaptation: expression levels of more than 70 genes relevant to transforming odors into spikes continuously vary across OSN subtypes, dynamically adjust to new environments over hours, and accurately predict acute OSN-specific odor responses. The sensory periphery therefore separates salient signals from predictable background via a transcriptional rheostat whose moment-to-moment state reflects the past and constrains the future; these findings suggest a general model in which structured transcriptional variation within a cell type reflects individual experience.
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Affiliation(s)
- Tatsuya Tsukahara
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - David H Brann
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stan L Pashkovski
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Thomas Bozza
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
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25
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Olfactory receptor choice: a case study for gene regulation in a multi-enhancer system. Curr Opin Genet Dev 2021; 72:101-109. [PMID: 34896807 DOI: 10.1016/j.gde.2021.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 12/14/2022]
Abstract
The mammalian genome possesses >2000 olfactory receptor (OR) alleles regulated by 63 known OR-Enhancer elements, yet each olfactory sensory neuron (OSN) expresses only a single OR allele. Choreographed changes to OSN nuclear architecture are evidently necessary for OR expression. Additionally, the insulated organization of OR-enhancers around an OR allele is a hallmark of the chosen OR. However, the biology guiding OR choice itself is unclear. Innovations in single-cell and biophysics-based analysis of nuclear architecture are revising previous models of the nucleus to include its dynamic and probabilistic nature. In this review, we ground current knowledge of OR gene regulation in these emerging theories to speculate on mechanisms that may give rise to diverse and singular OR expression.
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26
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Olfactory Stimulation Regulates the Birth of Neurons That Express Specific Odorant Receptors. Cell Rep 2021; 33:108210. [PMID: 33027656 PMCID: PMC7569022 DOI: 10.1016/j.celrep.2020.108210] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 07/03/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022] Open
Abstract
In mammals, olfactory sensory neurons (OSNs) are born throughout life, ostensibly solely to replace damaged OSNs. During differentiation, each OSN precursor “chooses,” out of hundreds of possibilities, a single odorant receptor (OR) gene, which defines the identity of the mature OSN. The relative neurogenesis rates of the hundreds of distinct OSN “subtypes” are thought to be constant, as they are determined by a stochastic process in which each OR is chosen with a fixed probability. Here, using histological, single-cell, and targeted affinity purification approaches, we show that closing one nostril in mice selectively reduces the number of newly generated OSNs of specific subtypes. Moreover, these reductions depend on an animal’s age and/or environment. Stimulation-dependent changes in the number of new OSNs are not attributable to altered rates of cell survival but rather production. Our findings indicate that the relative birth rates of distinct OSN subtypes depend on olfactory experience. In mammals, the odorant receptor identities of newly generated olfactory sensory neurons are thought to be determined by each progenitor cell’s random choice of a single receptor. Here, van der Linden et al. show that, in mice, the birth rates of neurons expressing a subset of receptors depend on olfactory stimulation.
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Francia S, Lodovichi C. The role of the odorant receptors in the formation of the sensory map. BMC Biol 2021; 19:174. [PMID: 34452614 PMCID: PMC8394594 DOI: 10.1186/s12915-021-01116-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 08/02/2021] [Indexed: 11/10/2022] Open
Abstract
In the olfactory system, odorant receptors (ORs) expressed at the cell membrane of olfactory sensory neurons detect odorants and direct sensory axons toward precise target locations in the brain, reflected in the presence of olfactory sensory maps. This dual role of ORs is corroborated by their subcellular expression both in cilia, where they bind odorants, and at axon terminals, a location suitable for axon guidance cues. Here, we provide an overview and discuss previous work on the role of ORs in establishing the topographic organization of the olfactory system and recent findings on the mechanisms of activation and function of axonal ORs.
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Affiliation(s)
- Simona Francia
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,Veneto Institute of Molecular Medicine, Padua, Italy
| | - Claudia Lodovichi
- Veneto Institute of Molecular Medicine, Padua, Italy. .,Neuroscience Institute CNR, Via Orus 2, 35129, Padua, Italy. .,Department of Biomedical Sciences, University of Padua, Padua, Italy. .,Padova Neuroscience Center, Padua, Italy.
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Manzini I, Schild D, Di Natale C. Principles of odor coding in vertebrates and artificial chemosensory systems. Physiol Rev 2021; 102:61-154. [PMID: 34254835 DOI: 10.1152/physrev.00036.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The biological olfactory system is the sensory system responsible for the detection of the chemical composition of the environment. Several attempts to mimic biological olfactory systems have led to various artificial olfactory systems using different technical approaches. Here we provide a parallel description of biological olfactory systems and their technical counterparts. We start with a presentation of the input to the systems, the stimuli, and treat the interface between the external world and the environment where receptor neurons or artificial chemosensors reside. We then delineate the functions of receptor neurons and chemosensors as well as their overall I-O relationships. Up to this point, our account of the systems goes along similar lines. The next processing steps differ considerably: while in biology the processing step following the receptor neurons is the "integration" and "processing" of receptor neuron outputs in the olfactory bulb, this step has various realizations in electronic noses. For a long period of time, the signal processing stages beyond the olfactory bulb, i.e., the higher olfactory centers were little studied. Only recently there has been a marked growth of studies tackling the information processing in these centers. In electronic noses, a third stage of processing has virtually never been considered. In this review, we provide an up-to-date overview of the current knowledge of both fields and, for the first time, attempt to tie them together. We hope it will be a breeding ground for better information, communication, and data exchange between very related but so far little connected fields.
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Affiliation(s)
- Ivan Manzini
- Animal Physiology and Molecular Biomedicine, Justus-Liebig-University Gießen, Gießen, Germany
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University Medical Center, University of Göttingen, Göttingen, Germany
| | - Corrado Di Natale
- Department of Electronic Engineering, University of Rome Tor Vergata, Rome, Italy
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Son G, Jahanshahi A, Yoo SJ, Boonstra JT, Hopkins DA, Steinbusch HWM, Moon C. Olfactory neuropathology in Alzheimer's disease: a sign of ongoing neurodegeneration. BMB Rep 2021. [PMID: 34162463 PMCID: PMC8249876 DOI: 10.5483/bmbrep.2021.54.6.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Gowoon Son
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Department of Neurosurgery, MUMC+, Maastricht 6202 AZ, the Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - Ali Jahanshahi
- Department of Neurosurgery, MUMC+, Maastricht 6202 AZ, the Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - Seung-Jun Yoo
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Korea
| | - Jackson T. Boonstra
- Department of Neurosurgery, MUMC+, Maastricht 6202 AZ, the Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - David A. Hopkins
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax B3H 4R2, Canada
| | - Harry W. M. Steinbusch
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - Cheil Moon
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Korea
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30
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Shah A, Ratkowski M, Rosa A, Feinstein P, Bozza T. Olfactory expression of trace amine-associated receptors requires cooperative cis-acting enhancers. Nat Commun 2021; 12:3797. [PMID: 34145232 PMCID: PMC8213819 DOI: 10.1038/s41467-021-23824-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 05/18/2021] [Indexed: 11/28/2022] Open
Abstract
Olfactory sensory neurons express a large family of odorant receptors (ORs) and a small family of trace amine-associated receptors (TAARs). While both families are subject to so-called singular expression (expression of one allele of one gene), the mechanisms underlying TAAR gene choice remain obscure. Here, we report the identification of two conserved sequence elements in the mouse TAAR cluster (T-elements) that are required for TAAR gene expression. We observed that cell-type-specific expression of a TAAR-derived transgene required either T-element. Moreover, deleting either element reduced or abolished expression of a subset of TAAR genes, while deleting both elements abolished olfactory expression of all TAARs in cis with the mutation. The T-elements exhibit several features of known OR enhancers but also contain highly conserved, unique sequence motifs. Our data demonstrate that TAAR gene expression requires two cooperative cis-acting enhancers and suggest that ORs and TAARs share similar mechanisms of singular expression.
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Affiliation(s)
- Ami Shah
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Madison Ratkowski
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Alessandro Rosa
- The Graduate Center Programs in Biochemistry, Biology and CUNY Neuroscience Collaborative, New York, NY, USA
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY, USA
| | - Paul Feinstein
- The Graduate Center Programs in Biochemistry, Biology and CUNY Neuroscience Collaborative, New York, NY, USA
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY, USA
| | - Thomas Bozza
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA.
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Son G, Jahanshahi A, Yoo SJ, Boonstra JT, Hopkins DA, Steinbusch HWM, Moon C. Olfactory neuropathology in Alzheimer's disease: a sign of ongoing neurodegeneration. BMB Rep 2021; 54:295-304. [PMID: 34162463 PMCID: PMC8249876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/06/2021] [Accepted: 05/06/2021] [Indexed: 11/08/2023] Open
Abstract
Olfactory neuropathology is a cause of olfactory loss in Alzheimer's disease (AD). Olfactory dysfunction is also associated with memory and cognitive dysfunction and is an incidental finding of AD dementia. Here we review neuropathological research on the olfactory system in AD, considering both structural and functional evidence. Experimental and clinical findings identify olfactory dysfunction as an early indicator of AD. In keeping with this, amyloid-β production and neuroinflammation are related to underlying causes of impaired olfaction. Notably, physiological features of the spatial map in the olfactory system suggest the evidence of ongoing neurodegeneration. Our aim in this review is to examine olfactory pathology findings essential to identifying mechanisms of olfactory dysfunction in the development of AD in hopes of supporting investigations leading towards revealing potential diagnostic methods and causes of early pathogenesis in the olfactory system. [BMB Reports 2021; 54(6): 295-304].
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Affiliation(s)
- Gowoon Son
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Department of Neurosurgery, MUMC+, Maastricht 6202 AZ, Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - Ali Jahanshahi
- Department of Neurosurgery, MUMC+, Maastricht 6202 AZ, Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - Seung-Jun Yoo
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Korea
| | - Jackson T. Boonstra
- Department of Neurosurgery, MUMC+, Maastricht 6202 AZ, Netherlands
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - David A. Hopkins
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax B3H 4R2, Canada
| | - Harry W. M. Steinbusch
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- School for Mental Health and Neuroscience, Maastricht University, Maastricht 6200 MD, the Netherlands
| | - Cheil Moon
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu 42988, Korea
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32
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Zapiec B, Mombaerts P. The Zonal Organization of Odorant Receptor Gene Choice in the Main Olfactory Epithelium of the Mouse. Cell Rep 2021; 30:4220-4234.e5. [PMID: 32209480 DOI: 10.1016/j.celrep.2020.02.110] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/16/2020] [Accepted: 02/27/2020] [Indexed: 12/15/2022] Open
Abstract
A mature olfactory sensory neuron (OSN) of the main olfactory epithelium (MOE) typically expresses one allele of one odorant receptor (OR) gene. It is widely thought that the great majority of the 1,141 intact mouse OR genes are expressed in one of four MOE zones (or bands or stripes), which are largely non-overlapping. Here, we develop a multiplex method to map, in 3D and MOE-wide, the expression areas of multiple OR genes in individual, non-genetically modified mice by three-color fluorescence in situ hybridization, semi-automated image segmentation, and 3D reconstruction. We classify the expression areas of 68 OR genes into 9 zones. These zones are highly overlapping and strikingly complex when viewed in 3D reconstructions. There could well be more zones. We propose that zones reflect distinct OSN types that are each restricted in their choice to a subset of the OR gene repertoire.
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Affiliation(s)
- Bolek Zapiec
- Max Planck Research Unit for Neurogenetics, Max-von-Laue-Strasse 4, 60438 Frankfurt, Germany
| | - Peter Mombaerts
- Max Planck Research Unit for Neurogenetics, Max-von-Laue-Strasse 4, 60438 Frankfurt, Germany.
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33
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Redolfi N, Lodovichi C. Spontaneous Afferent Activity Carves Olfactory Circuits. Front Cell Neurosci 2021; 15:637536. [PMID: 33767612 PMCID: PMC7985084 DOI: 10.3389/fncel.2021.637536] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/08/2021] [Indexed: 12/11/2022] Open
Abstract
Electrical activity has a key role in shaping neuronal circuits during development. In most sensory modalities, early in development, internally generated spontaneous activity sculpts the initial layout of neuronal wiring. With the maturation of the sense organs, the system relies more on sensory-evoked electrical activity. Stimuli-driven neuronal discharge is required for the transformation of immature circuits in the specific patterns of neuronal connectivity that subserve normal brain function. The olfactory system (OS) differs from this organizational plan. Despite the important role of odorant receptors (ORs) in shaping olfactory topography, odor-evoked activity does not have a prominent role in refining neuronal wiring. On the contrary, afferent spontaneous discharge is required to achieve and maintain the specific diagram of connectivity that defines the topography of the olfactory bulb (OB). Here, we provide an overview of the development of olfactory topography, with a focus on the role of afferent spontaneous discharge in the formation and maintenance of the specific synaptic contacts that result in the topographic organization of the OB.
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Affiliation(s)
- Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Claudia Lodovichi
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Neuroscience Institute CNR, Padua, Italy.,Veneto Institute of Molecular Medicine, Padua, Italy.,Padova Neuroscience Center, University of Padua, Padua, Italy
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34
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Keller LA, Merkel O, Popp A. Intranasal drug delivery: opportunities and toxicologic challenges during drug development. Drug Deliv Transl Res 2021; 12:735-757. [PMID: 33491126 PMCID: PMC7829061 DOI: 10.1007/s13346-020-00891-5] [Citation(s) in RCA: 150] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2020] [Indexed: 02/06/2023]
Abstract
Over the past 10 years, the interest in intranasal drug delivery in pharmaceutical R&D has increased. This review article summarises information on intranasal administration for local and systemic delivery, as well as for CNS indications. Nasal delivery offers many advantages over standard systemic delivery systems, such as its non-invasive character, a fast onset of action and in many cases reduced side effects due to a more targeted delivery. There are still formulation limitations and toxicological aspects to be optimised. Intranasal drug delivery in the field of drug development is an interesting delivery route for the treatment of neurological disorders. Systemic approaches often fail to efficiently supply the CNS with drugs. This review paper describes the anatomical, histological and physiological basis and summarises currently approved drugs for administration via intranasal delivery. Further, the review focuses on toxicological considerations of intranasally applied compounds and discusses formulation aspects that need to be considered for drug development.
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Affiliation(s)
- Lea-Adriana Keller
- Preclinical Safety, AbbVie Deutschland GmbH & Co. KG, Knollstrasse, 67061 Ludwigshafen, Germany
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians-University, Butenandtstraße 5-13, 81337 Munich, Germany
| | - Olivia Merkel
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians-University, Butenandtstraße 5-13, 81337 Munich, Germany
| | - Andreas Popp
- Preclinical Safety, AbbVie Deutschland GmbH & Co. KG, Knollstrasse, 67061 Ludwigshafen, Germany
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35
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Lodovichi C. Topographic organization in the olfactory bulb. Cell Tissue Res 2021; 383:457-472. [PMID: 33404841 PMCID: PMC7873094 DOI: 10.1007/s00441-020-03348-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/10/2020] [Indexed: 11/30/2022]
Abstract
The ability of the olfactory system to detect and discriminate a broad spectrum of odor molecules with extraordinary sensitivity relies on a wide range of odorant receptors and on the distinct architecture of neuronal circuits in olfactory brain areas. More than 1000 odorant receptors, distributed almost randomly in the olfactory epithelium, are plotted out in two mirror-symmetric maps of glomeruli in the olfactory bulb, the first relay station of the olfactory system. How does such a precise spatial arrangement of glomeruli emerge from a random distribution of receptor neurons? Remarkably, the identity of odorant receptors defines not only the molecular receptive range of sensory neurons but also their glomerular target. Despite their key role, odorant receptors are not the only determinant, since the specificity of neuronal connections emerges from a complex interplay between several molecular cues and electrical activity. This review provides an overview of the mechanisms underlying olfactory circuit formation. In particular, recent findings on the role of odorant receptors in regulating axon targeting and of spontaneous activity in the development and maintenance of synaptic connections are discussed.
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Affiliation(s)
- Claudia Lodovichi
- Neuroscience Institute CNR, Department of Biomedical Science, Veneto Institute of Molecular Medicine, Padova Neuroscience Center, Padova, Italy.
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36
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Son G, Yoo SJ, Kang S, Rasheed A, Jung DH, Park H, Cho B, Steinbusch HWM, Chang KA, Suh YH, Moon C. Region-specific amyloid-β accumulation in the olfactory system influences olfactory sensory neuronal dysfunction in 5xFAD mice. ALZHEIMERS RESEARCH & THERAPY 2021; 13:4. [PMID: 33397474 PMCID: PMC7784287 DOI: 10.1186/s13195-020-00730-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 11/23/2020] [Indexed: 01/10/2023]
Abstract
Background Hyposmia in Alzheimer’s disease (AD) is a typical early symptom according to numerous previous clinical studies. Although amyloid-β (Aβ), which is one of the toxic factors upregulated early in AD, has been identified in many studies, even in the peripheral areas of the olfactory system, the pathology involving olfactory sensory neurons (OSNs) remains poorly understood. Methods Here, we focused on peripheral olfactory sensory neurons (OSNs) and delved deeper into the direct relationship between pathophysiological and behavioral results using odorants. We also confirmed histologically the pathological changes in 3-month-old 5xFAD mouse models, which recapitulates AD pathology. We introduced a numeric scale histologically to compare physiological phenomenon and local tissue lesions regardless of the anatomical plane. Results We observed the odorant group that the 5xFAD mice showed reduced responses to odorants. These also did not physiologically activate OSNs that propagate their axons to the ventral olfactory bulb. Interestingly, the amount of accumulated amyloid-β (Aβ) was high in the OSNs located in the olfactory epithelial ectoturbinate and the ventral olfactory bulb glomeruli. We also observed irreversible damage to the ectoturbinate of the olfactory epithelium by measuring the impaired neuronal turnover ratio from the basal cells to the matured OSNs. Conclusions Our results showed that partial and asymmetrical accumulation of Aβ coincided with physiologically and structurally damaged areas in the peripheral olfactory system, which evoked hyporeactivity to some odorants. Taken together, partial olfactory dysfunction closely associated with peripheral OSN’s loss could be a leading cause of AD-related hyposmia, a characteristic of early AD. Supplementary Information The online version contains supplementary material available at 10.1186/s13195-020-00730-2.
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Affiliation(s)
- Gowoon Son
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.,School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Seung-Jun Yoo
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.,Convergence Research Advanced Centre for Olfaction, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.,Max Planck Research Unit for Neurogenetics, Frankfurt, Germany
| | - Shinwoo Kang
- Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Ameer Rasheed
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Da Hae Jung
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Hyunjun Park
- Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Bongki Cho
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.,Convergence Research Advanced Centre for Olfaction, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Harry W M Steinbusch
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.,School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Keun-A Chang
- Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Yoo-Hun Suh
- Department of Pharmacology, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Cheil Moon
- Department of Brain & Cognitive Sciences, Graduate School, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea. .,Convergence Research Advanced Centre for Olfaction, Daegu Gyeungbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea. .,Korea Brain Research Institute, Daegu, Republic of Korea.
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37
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Kurian SM, Naressi RG, Manoel D, Barwich AS, Malnic B, Saraiva LR. Odor coding in the mammalian olfactory epithelium. Cell Tissue Res 2021; 383:445-456. [PMID: 33409650 PMCID: PMC7873010 DOI: 10.1007/s00441-020-03327-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/27/2020] [Indexed: 12/31/2022]
Abstract
Noses are extremely sophisticated chemical detectors allowing animals to use scents to interpret and navigate their environments. Odor detection starts with the activation of odorant receptors (ORs), expressed in mature olfactory sensory neurons (OSNs) populating the olfactory mucosa. Different odorants, or different concentrations of the same odorant, activate unique ensembles of ORs. This mechanism of combinatorial receptor coding provided a possible explanation as to why different odorants are perceived as having distinct odors. Aided by new technologies, several recent studies have found that antagonist interactions also play an important role in the formation of the combinatorial receptor code. These findings mark the start of a new era in the study of odorant-receptor interactions and add a new level of complexity to odor coding in mammals.
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Affiliation(s)
| | | | | | | | - Bettina Malnic
- Department of Biochemistry, University of São Paulo, São Paulo, Brazil.
| | - Luis R Saraiva
- Sidra Medicine, Doha, Qatar.
- Monell Chemical Senses Center, Philadelphia, USA.
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
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38
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Diving into the streams and waves of constitutive and regenerative olfactory neurogenesis: insights from zebrafish. Cell Tissue Res 2020; 383:227-253. [PMID: 33245413 DOI: 10.1007/s00441-020-03334-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/02/2020] [Indexed: 02/06/2023]
Abstract
The olfactory system is renowned for its functional and structural plasticity, with both peripheral and central structures displaying persistent neurogenesis throughout life and exhibiting remarkable capacity for regenerative neurogenesis after damage. In general, fish are known for their extensive neurogenic ability, and the zebrafish in particular presents an attractive model to study plasticity and adult neurogenesis in the olfactory system because of its conserved structure, relative simplicity, rapid cell turnover, and preponderance of neurogenic niches. In this review, we present an overview of the anatomy of zebrafish olfactory structures, with a focus on the neurogenic niches in the olfactory epithelium, olfactory bulb, and ventral telencephalon. Constitutive and regenerative neurogenesis in both the peripheral olfactory organ and central olfactory bulb of zebrafish is reviewed in detail, and a summary of current knowledge about the cellular origin and molecular signals involved in regulating these processes is presented. While some features of physiologic and injury-induced neurogenic responses are similar, there are differences that indicate that regeneration is not simply a reiteration of the constitutive proliferation process. We provide comparisons to mammalian neurogenesis that reveal similarities and differences between species. Finally, we present a number of open questions that remain to be answered.
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39
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Abstract
In mammals, odor information detected by olfactory sensory neurons is converted to a topographic map of activated glomeruli in the olfactory bulb. Mitral cells and tufted cells transmit signals sequentially to the olfactory cortex for behavioral outputs. To elicit innate behavioral responses, odor signals are directly transmitted by distinct subsets of mitral cells from particular functional domains in the olfactory bulb to specific amygdala nuclei. As for the learned decisions, input signals are conveyed by tufted cells as well as by mitral cells to the olfactory cortex. Behavioral scene cells link the odor information to the valence cells in the amygdala to elicit memory-based behavioral responses. Olfactory decision and perception take place in relation to the respiratory cycle. How is the sensory quality imposed on the olfactory inputs for behavioral outputs? How are the two types of odor signals, innate and learned, processed during respiration? Here, we review recent progress on the study of neural circuits involved in decision making in the mouse olfactory system.
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Affiliation(s)
- Kensaku Mori
- RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan;
| | - Hitoshi Sakano
- Department of Brain Function, School of Medical Sciences, University of Fukui, Matsuoka, Fukui 910-1197, Japan;
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40
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Axonal Odorant Receptors Mediate Axon Targeting. Cell Rep 2020; 29:4334-4348.e7. [PMID: 31875544 PMCID: PMC6941231 DOI: 10.1016/j.celrep.2019.11.099] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 08/26/2019] [Accepted: 11/21/2019] [Indexed: 12/05/2022] Open
Abstract
In mammals, odorant receptors not only detect odors but also define the target in the olfactory bulb, where sensory neurons project to give rise to the sensory map. The odorant receptor is expressed at the cilia, where it binds odorants, and at the axon terminal. The mechanism of activation and function of the odorant receptor at the axon terminal is, however, still unknown. Here, we identify phosphatidylethanolamine-binding protein 1 as a putative ligand that activates the odorant receptor at the axon terminal and affects the turning behavior of sensory axons. Genetic ablation of phosphatidylethanolamine-binding protein 1 in mice results in a strongly disturbed olfactory sensory map. Our data suggest that the odorant receptor at the axon terminal of olfactory neurons acts as an axon guidance cue that responds to molecules originating in the olfactory bulb. The dual function of the odorant receptor links specificity of odor perception and axon targeting. Axonal odorant receptors respond to cues elaborated in the olfactory bulb PEBP1, expressed in the olfactory bulb, is a putative ligand of axonal receptors Genetic ablation of PEBP1 results in disrupted olfactory map in vivo Axonal odorant receptors modulate axon targeting in the sensory map formation
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Tan K, Jones SH, Lake BB, Chousal JN, Shum EY, Zhang L, Chen S, Sohni A, Pandya S, Gallo RL, Zhang K, Cook-Andersen H, Wilkinson MF. The role of the NMD factor UPF3B in olfactory sensory neurons. eLife 2020; 9:e57525. [PMID: 32773035 PMCID: PMC7452722 DOI: 10.7554/elife.57525] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/09/2020] [Indexed: 12/13/2022] Open
Abstract
The UPF3B-dependent branch of the nonsense-mediated RNA decay (NMD) pathway is critical for human cognition. Here, we examined the role of UPF3B in the olfactory system. Single-cell RNA-sequencing (scRNA-seq) analysis demonstrated considerable heterogeneity of olfactory sensory neuron (OSN) cell populations in wild-type (WT) mice, and revealed that UPF3B loss influences specific subsets of these cell populations. UPF3B also regulates the expression of a large cadre of antimicrobial genes in OSNs, and promotes the selection of specific olfactory receptor (Olfr) genes for expression in mature OSNs (mOSNs). RNA-seq and Ribotag analyses identified classes of mRNAs expressed and translated at different levels in WT and Upf3b-null mOSNs. Integrating multiple computational approaches, UPF3B-dependent NMD target transcripts that are candidates to mediate the functions of NMD in mOSNs were identified in vivo. Together, our data provides a valuable resource for the olfactory field and insights into the roles of NMD in vivo.
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Affiliation(s)
- Kun Tan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Samantha H Jones
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Blue B Lake
- Department of Bioengineering, University of California, San DiegoSan DiegoUnited States
| | - Jennifer N Chousal
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Eleen Y Shum
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Lingjuan Zhang
- Department of Dermatology, University of California, San DiegoSan DiegoUnited States
| | - Song Chen
- Department of Bioengineering, University of California, San DiegoSan DiegoUnited States
| | - Abhishek Sohni
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Shivam Pandya
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
| | - Richard L Gallo
- Department of Dermatology, University of California, San DiegoSan DiegoUnited States
| | - Kun Zhang
- Department of Bioengineering, University of California, San DiegoSan DiegoUnited States
| | - Heidi Cook-Andersen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
- Division of Biological Sciences, University of California, San DiegoSan DiegoUnited States
| | - Miles F Wilkinson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, School of Medicine University of California, San DiegoSan DiegoUnited States
- Institute of Genomic Medicine, University of California, San DiegoSan DiegoUnited States
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Cooper KW, Brann DH, Farruggia MC, Bhutani S, Pellegrino R, Tsukahara T, Weinreb C, Joseph PV, Larson ED, Parma V, Albers MW, Barlow LA, Datta SR, Di Pizio A. COVID-19 and the Chemical Senses: Supporting Players Take Center Stage. Neuron 2020; 107:219-233. [PMID: 32640192 PMCID: PMC7328585 DOI: 10.1016/j.neuron.2020.06.032] [Citation(s) in RCA: 212] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 12/11/2022]
Abstract
The main neurological manifestation of COVID-19 is loss of smell or taste. The high incidence of smell loss without significant rhinorrhea or nasal congestion suggests that SARS-CoV-2 targets the chemical senses through mechanisms distinct from those used by endemic coronaviruses or other common cold-causing agents. Here we review recently developed hypotheses about how SARS-CoV-2 might alter the cells and circuits involved in chemosensory processing and thereby change perception. Given our limited understanding of SARS-CoV-2 pathogenesis, we propose future experiments to elucidate disease mechanisms and highlight the relevance of this ongoing work to understanding how the virus might alter brain function more broadly.
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Affiliation(s)
- Keiland W Cooper
- Interdepartmental Neuroscience Program, University of California Irvine, Irvine, CA, USA
| | - David H Brann
- Harvard Medical School Department of Neurobiology, Boston, MA, USA
| | | | - Surabhi Bhutani
- School of Exercise and Nutritional Sciences, San Diego State University, San Diego, CA, USA
| | - Robert Pellegrino
- Department of Food Science, Institute of Agriculture, University of Tennessee, Knoxville, TN, USA; Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | | | - Caleb Weinreb
- Harvard Medical School Department of Neurobiology, Boston, MA, USA
| | - Paule V Joseph
- Division of Intramural Research, National Institute of Nursing Research (NINR) National Institutes of Health, Bethesda, MD, USA; National Institute on Alcohol Abuse and Alcoholism (NIAAA) National Institutes of Health, Bethesda, MD, USA
| | - Eric D Larson
- Department of Otolaryngology, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA and the Rocky Mountain Taste and Smell Center, Aurora, CO, USA
| | - Valentina Parma
- Department of Psychology, Temple University, Philadelphia, PA, USA
| | - Mark W Albers
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Linda A Barlow
- Department of Cell and Developmental Biology, Graduate Program in Cell Biology, Stem Cells and Development and the Rocky Mountain Taste and Smell Center, University of Colorado, School Medicine, Anschutz Medical Campus, Aurora, CO, USA.
| | | | - Antonella Di Pizio
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany.
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Lodovichi C. Role of Axonal Odorant Receptors in Olfactory Topography. Neurosci Insights 2020; 15:2633105520923411. [PMID: 32529185 PMCID: PMC7262975 DOI: 10.1177/2633105520923411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 04/10/2020] [Indexed: 11/17/2022] Open
Abstract
A unique feature in the organization of the olfactory system is the dual role of the odorant receptors: they detect odors in the nasal epithelium and they play an instructive role in the convergence of olfactory sensory neuron axons in specific loci, ie, glomeruli, in the olfactory bulb. The dual role is corroborated by the expression of the odorant receptors in 2 specific locations of the olfactory sensory neurons: the cilia that protrude in the nostril, where the odorant receptors interact with odors, and the axon terminal, a suitable location for a potential axon guidance molecule. The mechanism of activation and function of the odorant receptors expressed at the axon terminal remained unknown for almost 20 years. A recent study identified the first putative ligand of the axonal odorant receptors, phosphatidylethanolamine-binding protein1, a molecule expressed in the olfactory bulb. The distinctive mechanisms of activation of the odorant receptors expressed at the opposite locations in sensory neurons, by odors, at the cilia, and by molecules expressed in the olfactory bulb, at the axon terminal, explain the dual role of the odorant receptors and link the specificity of odor perception with its internal representation, in the topographic map.
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Affiliation(s)
- Claudia Lodovichi
- Neuroscience Institute CNR, Department of Biomedical Science, Padova, Italy.,PNC, Padova Neuroscience Center, Padova, Italy.,VIMM, Veneto Institute of Molecular Medicine, Padova, Italy
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Hu XS, Ikegami K, Vihani A, Zhu KW, Zapata M, de March CA, Do M, Vaidya N, Kucera G, Bock C, Jiang Y, Yohda M, Matsunami H. Concentration-Dependent Recruitment of Mammalian Odorant Receptors. eNeuro 2020; 7:ENEURO.0103-19.2019. [PMID: 32015097 PMCID: PMC7189481 DOI: 10.1523/eneuro.0103-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 12/20/2022] Open
Abstract
A fundamental challenge in studying principles of organization used by the olfactory system to encode odor concentration information has been identifying comprehensive sets of activated odorant receptors (ORs) across a broad concentration range inside freely behaving animals. In mammals, this has recently become feasible with high-throughput sequencing-based methods that identify populations of activated ORs in vivo In this study, we characterized the mouse OR repertoires activated by the two odorants, acetophenone (ACT) and 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), from 0.01% to 100% (v/v) as starting concentrations using phosphorylated ribosomal protein S6 capture followed by RNA-Seq. We found Olfr923 to be one of the most sensitive ORs that is enriched by ACT. Using a mouse line that genetically labels Olfr923-positive axons, we provided evidence that ACT activates the Olfr923 glomeruli in the olfactory bulb. Through molecular dynamics stimulations, we identified amino acid residues in the Olfr923 binding cavity that facilitate ACT binding. This study sheds light on the active process by which unique OR repertoires may collectively facilitate the discrimination of odorant concentrations.
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Affiliation(s)
- Xiaoyang Serene Hu
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
| | - Kentaro Ikegami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
- Tokyo University of Agriculture and Technology, Tokyo 183-8538, Japan
| | - Aashutosh Vihani
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
- Department of Neurobiology, Duke Institute for Brain Sciences, Duke University, Durham, NC 27710
| | - Kevin W Zhu
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
| | - Marcelo Zapata
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
| | - Claire A de March
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
| | - Matthew Do
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
| | - Natasha Vaidya
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
- North Carolina School of Science and Mathematics, Durham, NC 27705
| | - Gary Kucera
- DCI Rodent Cancer Models Shared Resource, Duke University Medical Center, Durham, NC 27710
| | - Cheryl Bock
- DCI Rodent Cancer Models Shared Resource, Duke University Medical Center, Durham, NC 27710
| | - Yue Jiang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
| | - Masafumi Yohda
- Tokyo University of Agriculture and Technology, Tokyo 183-8538, Japan
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
- Department of Neurobiology, Duke Institute for Brain Sciences, Duke University, Durham, NC 27710
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Direct Comparison of Odor Responses of Homologous Glomeruli in the Medial and Lateral Maps of the Mouse Olfactory Bulb. eNeuro 2020; 7:ENEURO.0449-19.2020. [PMID: 31974110 PMCID: PMC7073388 DOI: 10.1523/eneuro.0449-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/31/2019] [Accepted: 01/10/2020] [Indexed: 11/29/2022] Open
Abstract
Olfactory sensory neurons (OSNs) expressing same-type odorant receptors typically project to a pair of glomeruli in the medial and lateral sides of the olfactory bulbs (OBs) in rodents. This multiple glomerular representation of homologous inputs is considered to have more important functional roles for odor information processing than the redundant backup system. However, a consensus idea is lacking and this hinders interpretation of the phenomenon. In addition, the shared and unique odorant response properties of the homologous glomeruli remain unclear because the majority of medial glomeruli are hidden in the septal OB, and thus it is difficult to directly compare them. OSNs, which express trace amine-associated odorant receptors (TAARs), were recently identified that project to a pair of glomeruli uniquely located in the dorsal OB. In this study, we measured the odorant-induced calcium responses of homologous pairs of TAAR glomeruli simultaneously in anesthetized mice and directly compared their response patterns. We found that they exhibited similar temporal response patterns and could not find differences in onset latency, rise time, decay time, or response amplitude. However, the medial glomeruli had significantly larger respiration-locked calcium fluctuations than the lateral glomeruli. This trend was observed with/without odorant stimulation in postsynaptic neurons of GABAergic, dopaminergic, and mitral/tufted cells, but not in presynaptic olfactory sensory axon terminals. This indicates that, at least in these TAAR glomeruli, the medial rather than the lateral OB map enhances the respiration-locked rhythm and transfers this information to higher brain centers.
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Sakano H. Developmental regulation of olfactory circuit formation in mice. Dev Growth Differ 2020; 62:199-213. [PMID: 32112394 PMCID: PMC7318115 DOI: 10.1111/dgd.12657] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 12/11/2022]
Abstract
In mammals, odorants induce various behavioral responses that are critical to the survival of the individual and species. Binding signals of odorants to odorant receptors (ORs) expressed in the olfactory epithelia are converted to an odor map, a pattern of activated glomeruli, in the olfactory bulb (OB). This topographic map is used to identify odorants for memory‐based learned decisions. In the embryo, a coarse olfactory map is generated in the OB by a combination of dorsal‐ventral and anterior‐posterior targeting of olfactory sensory neurons (OSNs), using specific sets of axon‐guidance molecules. During the process of OSN projection, odor signals are sorted into distinct odor qualities in separate functional domains in the OB. Odor information is then conveyed by the projection neurons, mitral/tufted cells, to various regions in the olfactory cortex, particularly to the amygdala for innate olfactory decisions. Although the basic architecture of hard‐wired circuits is generated by a genetic program, innate olfactory responses are modified by neonatal odor experience in an activity‐dependent manner. Stimulus‐driven OR activity promotes post‐synaptic events and dendrite selection in the responding glomeruli making them larger. As a result, enhanced odor inputs in neonates establish imprinted olfactory memory that induces attractive responses in adults, even when the odor quality is innately aversive. In this paper, I will provide an overview of the recent progress made in the olfactory circuit formation in mice.
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Affiliation(s)
- Hitoshi Sakano
- Department of Brain Function, School of Medical Sciences, University of Fukui, Fukui, Japan
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Koyama S, Heinbockel T. The Effects of Essential Oils and Terpenes in Relation to Their Routes of Intake and Application. Int J Mol Sci 2020; 21:E1558. [PMID: 32106479 PMCID: PMC7084246 DOI: 10.3390/ijms21051558] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 12/18/2022] Open
Abstract
Essential oils have been used in multiple ways, i.e., inhaling, topically applying on the skin, and drinking. Thus, there are three major routes of intake or application involved: the olfactory system, the skin, and the gastro-intestinal system. Understanding these routes is important for clarifying the mechanisms of action of essential oils. Here we summarize the three systems involved, and the effects of essential oils and their constituents at the cellular and systems level. Many factors affect the rate of uptake of each chemical constituent included in essential oils. It is important to determine how much of each constituent is included in an essential oil and to use single chemical compounds to precisely test their effects. Studies have shown synergistic influences of the constituents, which affect the mechanisms of action of the essential oil constituents. For the skin and digestive system, the chemical components of essential oils can directly activate gamma aminobutyric acid (GABA) receptors and transient receptor potential channels (TRP) channels, whereas in the olfactory system, chemical components activate olfactory receptors. Here, GABA receptors and TRP channels could play a role, mostly when the signals are transferred to the olfactory bulb and the brain.
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Affiliation(s)
- Sachiko Koyama
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Thomas Heinbockel
- Department of Anatomy, College of Medicine, Howard University, Washington, DC 20059, USA
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A Group of Olfactory Receptor Alleles that Encode Full Length Proteins are Down-Regulated as Olfactory Sensory Neurons Mature. Sci Rep 2020; 10:1781. [PMID: 32020011 PMCID: PMC7000733 DOI: 10.1038/s41598-020-58779-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 01/21/2020] [Indexed: 11/08/2022] Open
Abstract
The family of olfactory receptors (ORs) subserves the sense of smell and includes both functional alleles and pseudogenes, the latter identified by mutations resulting in frame shift or premature truncation. During neuronal differentiation, nonfunctional ORs are expressed initially but then are switched out, and/or the olfactory sensory neurons (OSNs) expressing them die. We carried out a transcriptomic analysis of FACS-isolated cells from ΔSox2-eGFP, Neurog1-eGFP BAC and ΔOMP-eGFP strains of uninjured and olfactory bulbectomized transgenic mice that correspond to distinct stages in the progression from globose basal cell stem cells to fully mature OSNs. We analyzed the expression pattern of 1094 unique receptors across this progression and found that the vast majority were characterized by a typical and expected pattern of expression; i.e., levels of OR mRNA peaking in mature OSNs. However, 43 ORs, including several known pseudogenes, were different, such that mRNA expression declined in the mature OSNs relative to earlier stages. Protein and promoter sequence analysis of the atypical group did not uncover any obvious differences between them and more typical ORs. Nonetheless, the pattern of expression suggests that atypical ORs may be non-functional despite the lack of any obvious abnormality in the sequence analyses.
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Matsukawa M, Katsuyama N, Imada M, Aizawa S, Sato T. Simultaneous activities in both mirror-image glomerular maps in the olfactory bulb may have an important role in stress-related neuronal responses in mice. Brain Res 2020; 1732:146676. [PMID: 31981677 DOI: 10.1016/j.brainres.2020.146676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/09/2020] [Accepted: 01/18/2020] [Indexed: 10/25/2022]
Abstract
In the mouse olfactory bulb (OB), odor input from the olfactory epithelium innervates topographically to form odorant maps, which are mirror-image arrangements of glomerular clusters with domain organization. However, the functional role of the mirror-image representation in the OB remains unknown. Predator odors induce stress responses, and the dorsal domain of the dorsolateral wall of the olfactory bulb (dlOB) is known to be involved in this process. However, it remains unclear whether the activities in the medial wall of the OB (mOB), the other mirror half, are also involved in stress responses. Therefore, in this study, we investigated whether the mOB and dlOB are required for the induction of stress responses using lesioning or electrical stimulation. Although there were no significant differences in the number of activated neurons in the bed nucleus of the stria terminalis, posterior piriform cortex or amygdalo-piriform transition area, fewer activated neurons were observed in the anterior piriform cortex (APC) following lesion of both the mOB and dlOB combined. No changes were observed in the density of activated cells in any examined brain region following stimulation of either the mOB or dlOB alone. However, activated neurons in the APC were significantly more numerous following simultaneous stimulation of the mOB and dlOB. Collectively, our results suggest that simultaneous activation in both the mOB and dlOB is needed to induce APC neural activities that produce stress-like behavior. These findings provide insight into olfactory information processing, and may also help in the development of therapies for odor-induced stress behaviors.
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Affiliation(s)
- Mutsumi Matsukawa
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, 30-1 Oyaguchi-Kamicho, Itabashi, Tokyo 173-8610, Japan.
| | - Narumi Katsuyama
- Cognitive Neuroscience Section, Primate Research Institute, Kyoto University, 41-2, Kanrin, Inuyama, Aichi 484-8506, Japan
| | - Masato Imada
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, 30-1 Oyaguchi-Kamicho, Itabashi, Tokyo 173-8610, Japan
| | - Shin Aizawa
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, 30-1 Oyaguchi-Kamicho, Itabashi, Tokyo 173-8610, Japan
| | - Takaaki Sato
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
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50
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Soelter J, Schumacher J, Spors H, Schmuker M. Computational exploration of molecular receptive fields in the olfactory bulb reveals a glomerulus-centric chemical map. Sci Rep 2020; 10:77. [PMID: 31919393 PMCID: PMC6952415 DOI: 10.1038/s41598-019-56863-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 09/24/2019] [Indexed: 01/13/2023] Open
Abstract
Progress in olfactory research is currently hampered by incomplete knowledge about chemical receptive ranges of primary receptors. Moreover, the chemical logic underlying the arrangement of computational units in the olfactory bulb has still not been resolved. We undertook a large-scale approach at characterising molecular receptive ranges (MRRs) of glomeruli in the dorsal olfactory bulb (dOB) innervated by the MOR18-2 olfactory receptor, also known as Olfr78, with human ortholog OR51E2. Guided by an iterative approach that combined biological screening and machine learning, we selected 214 odorants to characterise the response of MOR18-2 and its neighbouring glomeruli. We found that a combination of conventional physico-chemical and vibrational molecular descriptors performed best in predicting glomerular responses using nonlinear Support-Vector Regression. We also discovered several previously unknown odorants activating MOR18-2 glomeruli, and obtained detailed MRRs of MOR18-2 glomeruli and their neighbours. Our results confirm earlier findings that demonstrated tunotopy, that is, glomeruli with similar tuning curves tend to be located in spatial proximity in the dOB. In addition, our results indicate chemotopy, that is, a preference for glomeruli with similar physico-chemical MRR descriptions being located in spatial proximity. Together, these findings suggest the existence of a partial chemical map underlying glomerular arrangement in the dOB. Our methodology that combines machine learning and physiological measurements lights the way towards future high-throughput studies to deorphanise and characterise structure-activity relationships in olfaction.
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Affiliation(s)
- Jan Soelter
- Neuroinformatics & Theoretical Neuroscience, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany
| | - Jan Schumacher
- Max-Planck-Institute for Biophysics, Max-von-Laue-Str. 3, 60438, Frankfurt/Main, Germany
| | - Hartwig Spors
- Max-Planck-Institute for Biophysics, Max-von-Laue-Str. 3, 60438, Frankfurt/Main, Germany
- Department of Neuropediatrics, Max-Liebig-University, Giessen, Germany
| | - Michael Schmuker
- Neuroinformatics & Theoretical Neuroscience, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany.
- Biocomputation Group, University of Hertfordshire, Hatfield, AL10 9AB, United Kingdom.
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