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Nakashima A, Takeuchi H. Roles of odorant receptors during olfactory glomerular map formation. Genesis 2024; 62:e23610. [PMID: 38874301 DOI: 10.1002/dvg.23610] [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: 01/03/2024] [Revised: 04/11/2024] [Accepted: 05/13/2024] [Indexed: 06/15/2024]
Abstract
The organization of the olfactory glomerular map involves the convergence of olfactory sensory neurons (OSNs) expressing the same odorant receptor (OR) into glomeruli in the olfactory bulb (OB). A remarkable feature of the olfactory glomerular map formation is that the identity of OR instructs the topography of the bulb, resulting in thousands of discrete glomeruli in mice. Several lines of evidence indicate that ORs control the expression levels of various kinds of transmembrane proteins to form glomeruli at appropriate regions of the OB. In this review, we will discuss how the OR identity is decoded by OSNs into gene expression through intracellular regulatory mechanisms.
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Affiliation(s)
- Ai Nakashima
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Haruki Takeuchi
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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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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Mori K, Sakano H. Circuit formation and sensory perception in the mouse olfactory system. Front Neural Circuits 2024; 18:1342576. [PMID: 38434487 PMCID: PMC10904487 DOI: 10.3389/fncir.2024.1342576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/01/2024] [Indexed: 03/05/2024] Open
Abstract
In the mouse olfactory system, odor information is converted to a topographic map of activated glomeruli in the olfactory bulb (OB). Although the arrangement of glomeruli is genetically determined, the glomerular structure is plastic and can be modified by environmental stimuli. If the pups are exposed to a particular odorant, responding glomeruli become larger recruiting the dendrites of connecting projection neurons and interneurons. This imprinting not only increases the sensitivity to the exposed odor, but also imposes the positive quality on imprinted memory. External odor information represented as an odor map in the OB is transmitted to the olfactory cortex (OC) and amygdala for decision making to elicit emotional and behavioral outputs using two distinct neural pathways, innate and learned. Innate olfactory circuits start to work right after birth, whereas learned circuits become functional later on. In this paper, the recent progress will be summarized in the study of olfactory circuit formation and odor perception in mice. We will also propose new hypotheses on the timing and gating of olfactory circuit activity in relation to the respiration cycle.
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Affiliation(s)
| | - Hitoshi Sakano
- Department of Brain Function, School of Medical Sciences, University of Fukui, Matsuoka, Japan
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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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Sridhar PS, Vasquez V, Monteil-Rivera F, Allingham JS, Loewen MC. A peroxidase-derived ligand that induces Fusarium graminearum Ste2 receptor-dependent chemotropism. Front Cell Infect Microbiol 2024; 13:1287418. [PMID: 38239502 PMCID: PMC10794396 DOI: 10.3389/fcimb.2023.1287418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024] Open
Abstract
Introduction The fungal G protein-coupled receptors Ste2 and Ste3 are vital in mediating directional hyphal growth of the agricultural pathogen Fusarium graminearum towards wheat plants. This chemotropism is induced by a catalytic product of peroxidases secreted by the wheat. Currently, the identity of this product, and the substrate it is generated from, are not known. Methods and results We provide evidence that a peroxidase substrate is derived from F. graminearum conidia and report a simple method to extract and purify the FgSte2-activating ligand for analyses by mass spectrometry. The mass spectra arising from t he ligand extract are characteristic of a 400 Da carbohydrate moiety. Consistent with this type of molecule, glycosidase treatment of F. graminearum conidia prior to peroxidase treatment significantly reduced the amount of ligand extracted. Interestingly, availability of the peroxidase substrate appears to depend on the presence of both FgSte2 and FgSte3, as knockout of one or the other reduces the chemotropism-inducing effect of the extracts. Conclusions While further characterization is necessary, identification of the F. graminearum-derived peroxidase substrate and the FgSte2-activating ligand will unearth deeper insights into the intricate mechanisms that underlie fungal pathogenesis in cereal crops, unveiling novel avenues for inhibitory interventions.
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Affiliation(s)
- Pooja S. Sridhar
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
| | - Vinicio Vasquez
- National Research Council of Canada, Aquatic and Crop Resources Development, Montreal, QC, Canada
| | - Fanny Monteil-Rivera
- National Research Council of Canada, Aquatic and Crop Resources Development, Montreal, QC, Canada
| | - John S. Allingham
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
| | - Michele C. Loewen
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
- National Research Council of Canada, Aquatic and Crop Resources Development, Ottawa, ON, Canada
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Zhang W, Mackay CR, Gershwin ME. Immunomodulatory Effects of Microbiota-Derived Short-Chain Fatty Acids in Autoimmune Liver Diseases. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:1629-1639. [PMID: 37186939 PMCID: PMC10188201 DOI: 10.4049/jimmunol.2300016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/01/2023] [Indexed: 05/17/2023]
Abstract
Nonpathogenic commensal microbiota and their metabolites and components are essential to maintain a tolerogenic environment and promote beneficial health effects. The metabolic environment critically impacts the outcome of immune responses and likely impacts autoimmune and allergic responses. Short-chain fatty acids (SCFAs) are the main metabolites produced by microbial fermentation in the gut. Given the high concentration of SCFAs in the gut and portal vein and their broad immune regulatory functions, SCFAs significantly influence immune tolerance and gut-liver immunity. Alterations of SCFA-producing bacteria and SCFAs have been identified in a multitude of inflammatory diseases. These data have particular significance in primary biliary cholangitis, primary sclerosing cholangitis, and autoimmune hepatitis because of the close proximity of the liver to the gut. In this focused review, we provide an update on the immunologic consequences of SCFA-producing microbiota and in particular on three dominant SCFAs in autoimmune liver diseases.
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Affiliation(s)
- Weici Zhang
- Division of Rheumatology, Allergy, and Clinical Immunology, School of Medicine, University of California Davis, CA, USA
| | - Charles R. Mackay
- Department of Microbiology, Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, Melbourne, Australia
| | - M. Eric Gershwin
- Division of Rheumatology, Allergy, and Clinical Immunology, School of Medicine, University of California Davis, CA, USA
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Park HK, Nguyen LP, Nguyen TU, Cho M, Nguyen HT, Hurh S, Kim HR, Seong JY, Lee CS, Ham BJ, Hwang JI. The N-terminus of CXCR4 splice variants determines expression and functional properties. PLoS One 2023; 18:e0283015. [PMID: 37141381 PMCID: PMC10159351 DOI: 10.1371/journal.pone.0283015] [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: 12/02/2022] [Accepted: 02/28/2023] [Indexed: 05/06/2023] Open
Abstract
C-X-C motif chemokine ligand 12(CXCL12) is an essential chemokine for organ development and homeostasis in multiple tissues. Its receptor, C-X-C chemokine receptor type 4(CXCR4), is expressed on the surface of target cells. The chemokine and receptor are expressed almost ubiquitously in human tissues and cells throughout life, and abnormal expression of CXCL12 and CXCR4 is observed in pathological conditions, such as inflammation and cancer. CXCR4 is reportedly translated into five splicing variants of different lengths, which each have different amino acids in the N-terminus. As the N-terminus is the first recognition site for chemokines, CXCR4 variants may respond differently to CXCL12. Despite these differences, the molecular and functional properties of CXCR4 variants have not been thoroughly described or compared. Here, we explored the expression of CXCR4 variants in cell lines and analyzed their roles in cellular responses using biochemical approaches. RT-PCR revealed that most cell lines express more than one CXCR4 variant. When expressed in HEK293 cells, the CXCR4 variants differed in protein expression efficiency and cell surface localization. Although variant 2 demonstrated the strongest expression and cell surface localization, variants 1, 3, and 5 also mediated chemokine signaling and induced cellular responses. Our results demonstrate that the N-terminal sequences of each CXCR4 variant determine the expression of the receptor and affect ligand recognition. Functional analyses revealed that CXCR4 variants may also affect each other or interact during CXCL12-stimulated cellular responses. Altogether, our results suggest that CXCR4 variants may have distinct functional roles that warrant additional investigation and could contribute to future development of novel drug interventions.
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Affiliation(s)
- Hee-Kyung Park
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Lan Phuong Nguyen
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Thai Uy Nguyen
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Minyeong Cho
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Huong Thi Nguyen
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Sunghoon Hurh
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Hong-Rae Kim
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Jae Young Seong
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Cheol Soon Lee
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Byung-Joo Ham
- Department of Psychiatry, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Jong-Ik Hwang
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, Republic of Korea
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9
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Billesbølle CB, de March CA, van der Velden WJC, Ma N, Tewari J, Del Torrent CL, Li L, Faust B, Vaidehi N, Matsunami H, Manglik A. Structural basis of odorant recognition by a human odorant receptor. Nature 2023; 615:742-749. [PMID: 36922591 PMCID: PMC10580732 DOI: 10.1038/s41586-023-05798-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 02/06/2023] [Indexed: 03/17/2023]
Abstract
Our sense of smell enables us to navigate a vast space of chemically diverse odour molecules. This task is accomplished by the combinatorial activation of approximately 400 odorant G protein-coupled receptors encoded in the human genome1-3. How odorants are recognized by odorant receptors remains unclear. Here we provide mechanistic insight into how an odorant binds to a human odorant receptor. Using cryo-electron microscopy, we determined the structure of the active human odorant receptor OR51E2 bound to the fatty acid propionate. Propionate is bound within an occluded pocket in OR51E2 and makes specific contacts critical to receptor activation. Mutation of the odorant-binding pocket in OR51E2 alters the recognition spectrum for fatty acids of varying chain length, suggesting that odorant selectivity is controlled by tight packing interactions between an odorant and an odorant receptor. Molecular dynamics simulations demonstrate that propionate-induced conformational changes in extracellular loop 3 activate OR51E2. Together, our studies provide a high-resolution view of chemical recognition of an odorant by a vertebrate odorant receptor, providing insight into how this large family of G protein-coupled receptors enables our olfactory sense.
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Affiliation(s)
| | - Claire A de March
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Institut de Chimie des Substances Naturelles, UPR2301 CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Wijnand J C van der Velden
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Jeevan Tewari
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Claudia Llinas Del Torrent
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
- Laboratory of Computational Medicine, Biostatistics Unit, Faculty of Medicine, Universitat Autònoma Barcelona, Bellaterra, Barcelona, Spain
| | - Linus Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Bryan Faust
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA.
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA.
- Department of Neurobiology, Duke Institute for Brain Sciences, Duke University, Durham, NC, USA.
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA.
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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10
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Nojima Y, Toriyama M, Tago K, Mizuno N, Morishita K, Itoh H. GPR56 C-terminal fragment mediates signal received by N-terminal fragment of another adhesion GPCR Latrophilin1 in neurons. Genes Cells 2023; 28:83-96. [PMID: 36453010 DOI: 10.1111/gtc.12994] [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: 11/20/2022] [Accepted: 11/25/2022] [Indexed: 12/03/2022]
Abstract
Adhesion GPCRs (aGPCRs) are a subfamily of GPCRs that are involved in cell adhesion, cell proliferation, and cell migration in various tissues. G protein-coupled receptor proteolytic site (GPS) of aGPCR is required to cleave the extracellular domain autocatalytically, generating two fragments; a N-terminal fragment (NTF) and a C-terminal fragment (CTF) containing seven transmembrane structure. NTF can interact with CTF non-covalently after cleavage, however the physiological significance of the cleavage of aGPCR at GPS, and also the interaction between NTF and CTF have not been fully clarified yet. In this study, we first investigated the expression profiles of two aGPCRs, GPR56/ADGRG1, and LPHN1/ADGRL1 in mouse brain, and found that the NTF and CTF of GPR56 independently expressed in different brain region at different developmental stages. Immunoprecipitation of GPR56CTF co-immunoprecipitated LPHN1NTF from mouse brain and HEK293T cells expressing both fragments. Stimulation with LPHN1 ligand, α-Latrotoxin N4C (αLTXN4C), to cells expressing LPHN1NTF and GPR56CTF increased intracellular Ca2+ concentration ([Ca2+ ]i). We also demonstrated that GPR56KO mouse neurons attenuated their Ca2+ response to αLTXN4C. These results suggest the possibility of functional and chimeric complex containing LPHN1NTF and GPR56CTF in neuronal signal transduction.
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Affiliation(s)
- Yusuke Nojima
- Laboratory of Molecular Signal Transduction, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
| | - Manami Toriyama
- Laboratory of Molecular Signal Transduction, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
| | - Kenji Tago
- Division of Structural Biochemistry, Department of Biochemistry, Jichi Medical University, Tochigi, Japan
| | - Norikazu Mizuno
- Faculty of Pharmaceutical Sciences, Aomori University, Aomori, Japan
| | - Kazuhiro Morishita
- Project for Advanced Medical Research and Development, Project Research Division, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan
| | - Hiroshi Itoh
- Laboratory of Molecular Signal Transduction, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
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Shayya HJ, Kahiapo JK, Duffié R, Lehmann KS, Bashkirova L, Monahan K, Dalton RP, Gao J, Jiao S, Schieren I, Belluscio L, Lomvardas S. ER stress transforms random olfactory receptor choice into axon targeting precision. Cell 2022; 185:3896-3912.e22. [PMID: 36167070 PMCID: PMC9588687 DOI: 10.1016/j.cell.2022.08.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/02/2022] [Accepted: 08/25/2022] [Indexed: 01/26/2023]
Abstract
Olfactory sensory neurons (OSNs) convert the stochastic choice of one of >1,000 olfactory receptor (OR) genes into precise and stereotyped axon targeting of OR-specific glomeruli in the olfactory bulb. Here, we show that the PERK arm of the unfolded protein response (UPR) regulates both the glomerular coalescence of like axons and the specificity of their projections. Subtle differences in OR protein sequences lead to distinct patterns of endoplasmic reticulum (ER) stress during OSN development, converting OR identity into distinct gene expression signatures. We identify the transcription factor Ddit3 as a key effector of PERK signaling that maps OR-dependent ER stress patterns to the transcriptional regulation of axon guidance and cell-adhesion genes, instructing targeting precision. Our results extend the known functions of the UPR from a quality-control pathway that protects cells from misfolded proteins to a sensor of cellular identity that interprets physiological states to direct axon wiring.
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Affiliation(s)
- Hani J Shayya
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Medical Scientist Training Program, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Jerome K Kahiapo
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Rachel Duffié
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Katherine S Lehmann
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lisa Bashkirova
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Kevin Monahan
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Ryan P Dalton
- The Miller Institute for Basic Research in Science, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Joanna Gao
- Barnard College, New York, NY 10025, USA
| | - Song Jiao
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ira Schieren
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Leonardo Belluscio
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stavros Lomvardas
- Mortimer B. Zuckerman Mind, Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University Irving Medical Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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12
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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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13
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Mori K, Sakano H. Neural Circuitry for Stress Information of Environmental and Internal Odor Worlds. Front Behav Neurosci 2022; 16:943647. [PMID: 35783233 PMCID: PMC9245520 DOI: 10.3389/fnbeh.2022.943647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 05/27/2022] [Indexed: 11/16/2022] Open
Abstract
In mammals, odor information detected in the olfactory epithelium is converted to a topographic map of activated glomeruli in the olfactory bulb. Odor signals are then conveyed by projection neurons to the olfactory cortex for decision making. Odor information is processed by two distinct pathways, one is innate and the other is learned, which are separately activated during exhalation and inhalation, respectively. There are two types of odor signals, exteroceptive and interoceptive, which are also processed in different phases of respiration. Exteroceptive sensory information whether attractive/pleasant or aversive/stressful, is evaluated by the valence regions in the amygdala. Stress is an alert signal telling the body to take an action so that the normal condition can be recovered. When the odor quality is negative, the brain sets up a behavioral strategy to avoid the danger or to improve the situation. In this review article, we will describe the recent progress in the study of olfactory perception focusing on stress responses to external and internal odors.
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Affiliation(s)
- Kensaku Mori
- RIKEN Center for Brain Science, Wako, Japan
- *Correspondence: Kensaku Mori,
| | - Hitoshi Sakano
- Department of Brain Function, School of Medical Sciences, University of Fukui, Fukui, Japan
- Hitoshi Sakano,
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14
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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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15
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Transcriptional adaptation of olfactory sensory neurons to GPCR identity and activity. Nat Commun 2022; 13:2929. [PMID: 35614043 PMCID: PMC9132991 DOI: 10.1038/s41467-022-30511-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/04/2022] [Indexed: 01/02/2023] Open
Abstract
In mammals, chemoperception relies on a diverse set of neuronal sensors able to detect chemicals present in the environment, and to adapt to various levels of stimulation. The contribution of endogenous and external factors to these neuronal identities remains to be determined. Taking advantage of the parallel coding lines present in the olfactory system, we explored the potential variations of neuronal identities before and after olfactory experience. We found that at rest, the transcriptomic profiles of mouse olfactory sensory neuron populations are already divergent, specific to the olfactory receptor they express, and are associated with the sequence of these latter. These divergent profiles further evolve in response to the environment, as odorant exposure leads to reprogramming via the modulation of transcription. These findings highlight a broad range of sensory neuron identities that are present at rest and that adapt to the experience of the individual, thus adding to the complexity and flexibility of sensory coding.
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16
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Functional analysis of human olfactory receptors with a high basal activity using LNCaP cell line. PLoS One 2022; 17:e0267356. [PMID: 35446888 PMCID: PMC9022881 DOI: 10.1371/journal.pone.0267356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 04/06/2022] [Indexed: 11/19/2022] Open
Abstract
Humans use a family of more than 400 olfactory receptors (ORs) to detect odorants. However, deorphanization of ORs is a critical issue because the functional properties of more than 80% of ORs remain unknown, thus, hampering our understanding of the relationship between receptor function and perception. HEK293 cells are the most commonly used heterologous expression system to determine the function of a given OR; however, they cannot functionally express a majority of ORs probably due to a lack of factor(s) required in cells in which ORs function endogenously. Interestingly, ORs have been known to be expressed in a variety of cells outside the nose and play critical physiological roles. These findings prompted us to test the capacity of cells to functionally express a specific repertoire of ORs. In this study, we selected three cell lines that endogenously express functional ORs. We demonstrated that human prostate carcinoma (LNCaP) cell lines successfully identified novel ligands for ORs that were not recognized when expressed in HEK293 cells. Further experiments suggested that the LNCaP cell line was effective for functional expression of ORs, especially with a high basal activity, which impeded the sensitive detection of ligand-mediated activity of ORs. This report provides an efficient functional assay system for a specific repertoire of ORs that cannot be characterized in current cell systems.
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17
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Wang IH, Murray E, Andrews G, Jiang HC, Park SJ, Donnard E, Durán-Laforet V, Bear DM, Faust TE, Garber M, Baer CE, Schafer DP, Weng Z, Chen F, Macosko EZ, Greer PL. Spatial transcriptomic reconstruction of the mouse olfactory glomerular map suggests principles of odor processing. Nat Neurosci 2022; 25:484-492. [PMID: 35314823 PMCID: PMC9281876 DOI: 10.1038/s41593-022-01030-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 02/07/2022] [Indexed: 12/14/2022]
Abstract
The olfactory system's ability to detect and discriminate between the vast array of chemicals present in the environment is critical for an animal's survival. In mammals, the first step of this odor processing is executed by olfactory sensory neurons, which project their axons to a stereotyped location in the olfactory bulb (OB) to form glomeruli. The stereotyped positioning of glomeruli in the OB suggests an importance for this organization in odor perception. However, because the location of only a limited subset of glomeruli has been determined, it has been challenging to determine the relationship between glomerular location and odor discrimination. Using a combination of single-cell RNA sequencing, spatial transcriptomics and machine learning, we have generated a map of most glomerular positions in the mouse OB. These observations significantly extend earlier studies and suggest an overall organizational principle in the OB that may be used by the brain to assist in odor decoding.
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Affiliation(s)
- I-Hao Wang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Evan Murray
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Greg Andrews
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Hao-Ching Jiang
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sung Jin Park
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Elisa Donnard
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Violeta Durán-Laforet
- Department of Neurobiology and Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Daniel M Bear
- Department of Psychology, Stanford University, Palo Alto, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Palo Alto, CA, USA
| | - Travis E Faust
- Department of Neurobiology and Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Manuel Garber
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Christina E Baer
- Sanderson Center for Optical Imaging and Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dorothy P Schafer
- Department of Neurobiology and Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Fei Chen
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
| | - Evan Z Macosko
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA
| | - Paul L Greer
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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18
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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: 32] [Impact Index Per Article: 10.7] [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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19
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Denda M, Nakanishi S. Do epidermal keratinocytes have sensory and information processing systems? Exp Dermatol 2021; 31:459-474. [PMID: 34726302 DOI: 10.1111/exd.14494] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 10/26/2021] [Accepted: 10/30/2021] [Indexed: 01/22/2023]
Abstract
It was long considered that the role of epidermal keratinocytes is solely to construct a water-impermeable protective membrane, the stratum corneum, at the uppermost layer of the skin. However, in the last two decades, it has been found that keratinocytes contain multiple sensory systems that detect environmental changes, including mechanical stimuli, sound, visible radiation, electric fields, magnetic fields, temperature and chemical stimuli, and also a variety of receptor molecules associated with olfactory or taste sensation. Moreover, neurotransmitters and their receptors that play crucial roles in the brain are functionally expressed in keratinocytes. Recent studies have demonstrated that excitation of keratinocytes can induce sensory perception in the brain. Here, we review the sensory and information processing capabilities of keratinocytes. We discuss the possibility that epidermal keratinocytes might represent the earliest stage in the development of the brain during the evolution of vertebrates.
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Affiliation(s)
- Mitsuhiro Denda
- Institute for Advanced Study of Mathematical Sciences, Meiji University, Nakano-ku, Tokyo, 164-8525, Japan
| | - Shinobu Nakanishi
- Shiseido Global Innovation Center, Nishi-ku, Yokohama, 220-0011, Japan
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20
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Timsit Y, Grégoire SP. Towards the Idea of Molecular Brains. Int J Mol Sci 2021; 22:ijms222111868. [PMID: 34769300 PMCID: PMC8584932 DOI: 10.3390/ijms222111868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.
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Affiliation(s)
- Youri Timsit
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 3 rue Michel-Ange, 75016 Paris, France
- Correspondence:
| | - Sergeant-Perthuis Grégoire
- Institut de Mathématiques de Jussieu—Paris Rive Gauche (IMJ-PRG), UMR 7586, CNRS-Université Paris Diderot, 75013 Paris, France;
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21
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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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22
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Kotthoff M, Bauer J, Haag F, Krautwurst D. Conserved C-terminal motifs in odorant receptors instruct their cell surface expression and cAMP signaling. FASEB J 2021; 35:e21274. [PMID: 33464692 DOI: 10.1096/fj.202000182rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 10/30/2020] [Accepted: 11/30/2020] [Indexed: 11/11/2022]
Abstract
The highly individual plasma membrane expression and cAMP signaling of odorant receptors have hampered their ligand assignment and functional characterization in test cell systems. Chaperones have been identified to support the cell surface expression of only a portion of odorant receptors, with mechanisms remaining unclear. The presence of amino acid motifs that might be responsible for odorant receptors' individual intracellular retention or cell surface expression, and thus, for cAMP signaling, is under debate: so far, no such protein motifs have been suggested. Here, we demonstrate the existence of highly conserved C-terminal amino acid motifs, which discriminate at least between class-I and class-II odorant receptors, with their numbers of motifs increasing during evolution, by comparing C-terminal protein sequences from 4808 receptors across eight species. Truncation experiments and mutation analysis of C-terminal motifs, largely overlapping with helix 8, revealed single amino acids and their combinations to have differential impact on the cell surface expression and on stimulus-dependent cAMP signaling of odorant receptors in NxG 108CC15 cells. Our results demonstrate class-specific and individual C-terminal motif equipment of odorant receptors, which instruct their functional expression in a test cell system, and in situ may regulate their individual cell surface expression and intracellular cAMP signaling.
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Affiliation(s)
| | - Julia Bauer
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Franziska Haag
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Dietmar Krautwurst
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
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23
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Fei A, Wu W, Tan L, Tang C, Xu Z, Huo X, Bao H, Kong Y, Johnson M, Hartmann G, Talay M, Yang C, Riegler C, Herrera KJ, Engert F, Xie XS, Barnea G, Liberles SD, Yang H, Li Q. Coordination of two enhancers drives expression of olfactory trace amine-associated receptors. Nat Commun 2021; 12:3798. [PMID: 34145235 PMCID: PMC8213717 DOI: 10.1038/s41467-021-23823-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 05/18/2021] [Indexed: 02/05/2023] Open
Abstract
Olfactory sensory neurons (OSNs) are functionally defined by their expression of a unique odorant receptor (OR). Mechanisms underlying singular OR expression are well studied, and involve a massive cross-chromosomal enhancer interaction network. Trace amine-associated receptors (TAARs) form a distinct family of olfactory receptors, and here we find that mechanisms regulating Taar gene choice display many unique features. The epigenetic signature of Taar genes in TAAR OSNs is different from that in OR OSNs. We further identify that two TAAR enhancers conserved across placental mammals are absolutely required for expression of the entire Taar gene repertoire. Deletion of either enhancer dramatically decreases the expression probabilities of different Taar genes, while deletion of both enhancers completely eliminates the TAAR OSN populations. In addition, both of the enhancers are sufficient to drive transgene expression in the partially overlapped TAAR OSNs. We also show that the TAAR enhancers operate in cis to regulate Taar gene expression. Our findings reveal a coordinated control of Taar gene choice in OSNs by two remote enhancers, and provide an excellent model to study molecular mechanisms underlying formation of an olfactory subsystem.
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Affiliation(s)
- Aimei Fei
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wanqing Wu
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Longzhi Tan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Cheng Tang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brian-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhengrong Xu
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaona Huo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brian-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hongqiang Bao
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yalei Kong
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mark Johnson
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, USA
| | - Griffin Hartmann
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, USA
| | - Mustafa Talay
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, USA
| | - Cheng Yang
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Clemens Riegler
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Kristian J Herrera
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Florian Engert
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - X Sunney Xie
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Gilad Barnea
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI, USA
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Hui Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brian-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qian Li
- Center for Brain Science of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai, China.
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24
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Widespread Inhibition, Antagonism, and Synergy in Mouse Olfactory Sensory Neurons In Vivo. Cell Rep 2021; 31:107814. [PMID: 32610120 DOI: 10.1016/j.celrep.2020.107814] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 05/05/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
Sensory information is selectively or non-selectively enhanced and inhibited in the brain, but it remains unclear whether and how this occurs at the most peripheral level. Using in vivo calcium imaging of mouse olfactory bulb and olfactory epithelium in wild-type and mutant animals, we show that odors produce not only excitatory but also inhibitory responses in olfactory sensory neurons (OSNs). Heterologous assays indicate that odorants can act as agonists to some but inverse agonists to other odorant receptors. We also demonstrate that responses to odor mixtures are extensively suppressed or enhanced in OSNs. When high concentrations of odors are mixed, widespread antagonism suppresses the overall response amplitudes and density. In contrast, a mixture of low concentrations of odors often produces synergistic effects and boosts the faint odor inputs. Thus, odor responses are extensively tuned by inhibition, antagonism, and synergy at the most peripheral level, contributing to robust sensory representations.
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25
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Inoue N, Nishizumi H, Ooyama R, Mogi K, Nishimori K, Kikusui T, Sakano H. The olfactory critical period is determined by activity-dependent Sema7A/PlxnC1 signaling within glomeruli. eLife 2021; 10:65078. [PMID: 33780330 PMCID: PMC8007213 DOI: 10.7554/elife.65078] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/18/2021] [Indexed: 12/26/2022] Open
Abstract
In mice, early exposure to environmental odors affects social behaviors later in life. A signaling molecule, Semaphorin 7A (Sema7A), is induced in the odor-responding olfactory sensory neurons. Plexin C1 (PlxnC1), a receptor for Sema7A, is expressed in mitral/tufted cells, whose dendrite-localization is restricted to the first week after birth. Sema7A/PlxnC1 signaling promotes post-synaptic events and dendrite selection in mitral/tufted cells, resulting in glomerular enlargement that causes an increase in sensitivity to the experienced odor. Neonatal odor experience also induces positive responses to the imprinted odor. Knockout and rescue experiments indicate that oxytocin in neonates is responsible for imposing positive quality on imprinted memory. In the oxytocin knockout mice, the sensitivity to the imprinted odor increases, but positive responses cannot be promoted, indicating that Sema7A/PlxnC1 signaling and oxytocin separately function. These results give new insights into our understanding of olfactory imprinting during the neonatal critical period.
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Affiliation(s)
- Nobuko Inoue
- Department of Brain Function, School of Medical Sciences, University of Fukui, Matsuoka, Japan
| | - Hirofumi Nishizumi
- Department of Brain Function, School of Medical Sciences, University of Fukui, Matsuoka, Japan
| | - Rumi Ooyama
- Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University, Sagamihara, Japan
| | - Kazutaka Mogi
- Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University, Sagamihara, Japan
| | - Katsuhiko Nishimori
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Takefumi Kikusui
- Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University, Sagamihara, Japan
| | - Hitoshi Sakano
- Department of Brain Function, School of Medical Sciences, University of Fukui, Matsuoka, Japan
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26
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Qiu Q, Wu Y, Ma L, Xu W, Hills M, Ramalingam V, Yu CR. Acquisition of innate odor preference depends on spontaneous and experiential activities during critical period. eLife 2021; 10:e60546. [PMID: 33769278 PMCID: PMC8032394 DOI: 10.7554/elife.60546] [Citation(s) in RCA: 10] [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: 06/29/2020] [Accepted: 03/24/2021] [Indexed: 01/15/2023] Open
Abstract
Animals possess an inborn ability to recognize certain odors to avoid predators, seek food, and find mates. Innate odor preference is thought to be genetically hardwired. Here we report that acquisition of innate odor recognition requires spontaneous neural activity and is influenced by sensory experience during early postnatal development. Genetic silencing of mouse olfactory sensory neurons during the critical period has little impact on odor sensitivity, discrimination, and recognition later in life. However, it abolishes innate odor preference and alters the patterns of activation in brain centers. Exposure to innately recognized odors during the critical period abolishes the associated valence in adulthood in an odor-specific manner. The changes are associated with broadened projection of olfactory sensory neurons and expression of axon guidance molecules. Thus, a delicate balance of neural activity is needed during the critical period in establishing innate odor preference and convergent axon input is required to encode innate odor valence.
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Affiliation(s)
- Qiang Qiu
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Yunming Wu
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Limei Ma
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Wenjing Xu
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Max Hills
- Stowers Institute for Medical ResearchKansas CityUnited States
| | - Vivekanandan Ramalingam
- Stowers Institute for Medical ResearchKansas CityUnited States
- Interdisciplinary Graduate Program in Biomedical Sciences, University of Kansas Medical CenterKansas CityUnited States
| | - C Ron Yu
- Stowers Institute for Medical ResearchKansas CityUnited States
- Interdisciplinary Graduate Program in Biomedical Sciences, University of Kansas Medical CenterKansas CityUnited States
- Department of Anatomy and Cell Biology, University of Kansas Medical CenterKansas CityUnited States
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27
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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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28
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Chen Z, Traniello IM, Rana S, Cash-Ahmed AC, Sankey AL, Yang C, Robinson GE. Neurodevelopmental and transcriptomic effects of CRISPR/Cas9-induced somatic orco mutation in honey bees. J Neurogenet 2021; 35:320-332. [PMID: 33666542 DOI: 10.1080/01677063.2021.1887173] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In insects, odorant receptors facilitate olfactory communication and require the functionality of the highly conserved co-receptor gene orco. Genome editing studies in a few species of ants and moths have revealed that orco can also have a neurodevelopmental function, in addition to its canonical role in adult olfaction, discovered first in Drosophila melanogaster. To extend this analysis, we determined whether orco mutations also affect the development of the adult brain of the honey bee Apis mellifera, an important model system for social behavior and chemical communication. We used CRISPR/Cas9 to knock out orco and examined anatomical and molecular consequences. To increase efficiency, we coupled embryo microinjection with a laboratory egg collection and in vitro rearing system. This new workflow advances genomic engineering technologies in honey bees by overcoming restrictions associated with field studies. We used Sanger sequencing to quickly select individuals with complete orco knockout for neuroanatomical analyses and later validated and described the mutations with amplicon sequencing. Mutant bees had significantly fewer glomeruli, smaller total volume of all the glomeruli, and higher mean individual glomerulus volume in the antennal lobe compared to wild-type controls. RNA-Sequencing revealed that orco knockout also caused differential expression of hundreds of genes in the antenna, including genes related to neural development and genes encoding odorant receptors. The expression of other types of chemoreceptor genes was generally unaffected, reflecting specificity of CRISPR activity in this study. These results suggest that neurodevelopmental effects of orco are related to specific insect life histories.
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Affiliation(s)
- Zhenqing Chen
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Ian M Traniello
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Seema Rana
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Amy C Cash-Ahmed
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Alison L Sankey
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Che Yang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Biochemistry Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Gene E Robinson
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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29
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Boccaccio A, Menini A, Pifferi S. The cyclic AMP signaling pathway in the rodent main olfactory system. Cell Tissue Res 2021; 383:429-443. [PMID: 33447881 DOI: 10.1007/s00441-020-03391-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/10/2020] [Indexed: 01/15/2023]
Abstract
Odor perception begins with the detection of odorant molecules by the main olfactory epithelium located in the nasal cavity. Odorant molecules bind to and activate a large family of G-protein-coupled odorant receptors and trigger a cAMP-mediated transduction cascade that converts the chemical stimulus into an electrical signal transmitted to the brain. Morever, odorant receptors and cAMP signaling plays a relevant role in olfactory sensory neuron development and axonal targeting to the olfactory bulb. This review will first explore the physiological response of olfactory sensory neurons to odorants and then analyze the different components of cAMP signaling and their different roles in odorant detection and olfactory sensory neuron development.
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Affiliation(s)
- Anna Boccaccio
- Institute of Biophysics, National Research Council (CNR), Genova, Italy.
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.,Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
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30
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Dibattista M, Al Koborssy D, Genovese F, Reisert J. The functional relevance of olfactory marker protein in the vertebrate olfactory system: a never-ending story. Cell Tissue Res 2021; 383:409-427. [PMID: 33447880 DOI: 10.1007/s00441-020-03349-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022]
Abstract
Olfactory marker protein (OMP) was first described as a protein expressed in olfactory receptor neurons (ORNs) in the nasal cavity. In particular, OMP, a small cytoplasmic protein, marks mature ORNs and is also expressed in the neurons of other nasal chemosensory systems: the vomeronasal organ, the septal organ of Masera, and the Grueneberg ganglion. While its expression pattern was more easily established, OMP's function remained relatively vague. To date, most of the work to understand OMP's role has been done using mice lacking OMP. This mostly phenomenological work has shown that OMP is involved in sharpening the odorant response profile and in quickening odorant response kinetics of ORNs and that it contributes to targeting of ORN axons to the olfactory bulb to refine the glomerular response map. Increasing evidence shows that OMP acts at the early stages of olfactory transduction by modulating the kinetics of cAMP, the second messenger of olfactory transduction. However, how this occurs at a mechanistic level is not understood, and it might also not be the only mechanism underlying all the changes observed in mice lacking OMP. Recently, OMP has been detected outside the nose, including the brain and other organs. Although no obvious logic has become apparent regarding the underlying commonality between nasal and extranasal expression of OMP, a broader approach to diverse cellular systems might help unravel OMP's functions and mechanisms of action inside and outside the nose.
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Affiliation(s)
- Michele Dibattista
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari "A. Moro", Bari, Italy
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31
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Nakashima N, Nakashima K, Nakashima A, Takano M. Olfactory marker protein interacts with adenosine nucleotide derivatives. Biochem Biophys Rep 2021; 25:100887. [PMID: 33490644 PMCID: PMC7806522 DOI: 10.1016/j.bbrep.2020.100887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/27/2020] [Accepted: 12/18/2020] [Indexed: 11/13/2022] Open
Abstract
Olfactory marker protein (OMP) is a genetic signature for mature olfactory receptor neurons (ORNs). Recently, it has been proposed that OMP directly captures odour-induced cAMP to swiftly terminate the olfactory signal transduction to maintain neuronal sensitivity. In the present study, we show that OMP can also interact with other adenosine nucleotides as ATP, ADP and AMP with different affinities. We performed bioluminescent resonant energy transfer (BRET) assay to measure the binding actions of the adenosine nucleotide derivatives in competition to cAMP. Amongst all, ATP showed the bell-shape affinity to OMP in the presence of cAMP; ADP and AMP showed fewer affinities to OMP than ATP. In the absence of cAMP analogues, ATP alone bound to OMP in a dose dependent manner with a lower affinity than to cAMP. Thus, OMP possessed different affinities to ATP in the presence or absence of cAMP. OMP may interact differentially with ATP and cAMP depending on its supply and demand along the cAMP-associated signalling in the limited spaces of cilia of ORNs. Olfactory marker protein (OMP) contains cAMP-binding sites. The affinity of OMP towards adenosine nucleotide derivatives was studied. OMP showed sigmoid-shaped affinity towards ATP. OMP showed U-shaped affinity towards ATP in competition with cAMP. OMP dose-dependently and differentially captured ATP.
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Affiliation(s)
- Noriyuki Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Kie Nakashima
- Laboratory of Developmental Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshida Hon-machi, Kyoto, 606-8501, Japan
| | - Akiko Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
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32
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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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33
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Vihani A, Hu XS, Gundala S, Koyama S, Block E, Matsunami H. Semiochemical responsive olfactory sensory neurons are sexually dimorphic and plastic. eLife 2020; 9:e54501. [PMID: 33231170 PMCID: PMC7732343 DOI: 10.7554/elife.54501] [Citation(s) in RCA: 12] [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: 12/16/2019] [Accepted: 11/22/2020] [Indexed: 01/21/2023] Open
Abstract
Understanding how genes and experience work in concert to generate phenotypic variability will provide a better understanding of individuality. Here, we considered this in the main olfactory epithelium, a chemosensory structure with over a thousand distinct cell types in mice. We identified a subpopulation of olfactory sensory neurons, defined by receptor expression, whose abundances were sexually dimorphic. This subpopulation of olfactory sensory neurons was over-represented in sex-separated mice and robustly responsive to sex-specific semiochemicals. Sex-combined housing led to an attenuation of the dimorphic representations. Single-cell sequencing analysis revealed an axis of activity-dependent gene expression amongst a subset of the dimorphic OSN populations. Finally, the pro-apoptotic gene Baxwas necessary to generate the dimorphic representations. Altogether, our results suggest a role of experience and activity in influencing homeostatic mechanisms to generate a robust sexually dimorphic phenotype in the main olfactory epithelium.
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Affiliation(s)
- Aashutosh Vihani
- Department of Neurobiology, Neurobiology Graduate Program, Duke University Medical CenterDurhamUnited States
| | - Xiaoyang Serene Hu
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Sivaji Gundala
- Department of Chemistry, University at Albany, State University of New YorkAlbanyUnited States
| | - Sachiko Koyama
- School of Medicine, Medical Sciences, Indiana UniversityBloomingtonUnited States
| | - Eric Block
- Department of Chemistry, University at Albany, State University of New YorkAlbanyUnited States
| | - Hiroaki Matsunami
- Department of Neurobiology, Neurobiology Graduate Program, Duke University Medical CenterDurhamUnited States
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
- Duke Institute for Brain Sciences, Duke UniversityDurhamUnited States
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34
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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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35
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Nakashima A, Nakagawa T, Takano M, Nakashima N. Olfactory marker protein contributes to the evaluation of odour values by olfactory glomerular processing. Neurosci Lett 2020; 739:135445. [PMID: 33148443 DOI: 10.1016/j.neulet.2020.135445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/02/2020] [Accepted: 10/15/2020] [Indexed: 01/05/2023]
Abstract
Olfaction starts from olfactory receptor neurons (ORNs) that express olfactory marker protein (OMP). OMP deficit results in various behavioural phenotypes indicating olfactory dysfunction due to the impaired responses of ORNs. Recently, OMP was demonstrated to maintain strong olfaction by buffering olfactory cAMP signalling. However, the impact of OMP on olfaction behaviours, the assessment of which requires time to evaluate odour values, remains largely unexplained. Here, we examined the behaviour of heterozygous OMP+/GFP (HET) mice vs. homologous GFP-knock-in OMP-deficient OMP GFP/ GFP (KI) mice during the olfactory investigation of odours with different values. When a swab containing an organic odour was presented, both HET and KI mice swiftly approached and investigated the swab with gradual habituation over test sessions. However, when another similar odour was presented, KI mice investigated the new swab much less intensively than HET mice. Next, mice were placed in a chamber with an aversive odour source in one corner of a test chamber. KI mice more frequently approached the compartment containing the aversive odour source than HET mice. Finally, we trained mice to associate two odours with solutions by utilizing reward-penalty values. HET mice stayed close to the reward-associated odour, while KI mice initially approached the reward-associated odour, occasionally turned towards the penalty-associated odour source and eventually stayed in the reward-odour compartment. Histologically, c-Fos-expressing juxtaglomerular cells were fewer and more broadly distributed around glomeruli in KI mice than HET mice. In conclusion, OMP contributes to the evaluation of odour values by glomerular processing during an olfactory investigation task.
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Affiliation(s)
- Akiko Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Taku Nakagawa
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan; Department of Anaesthesiology, Graduate School of Medicine, Kyushu University, Fukuoka, 812-8582, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Noriyuki Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan.
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36
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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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Nakashima N, Nakashima K, Nakashima A, Takano M. Olfactory marker protein elevates basal cAMP concentration. Biochem Biophys Res Commun 2020; 531:203-208. [PMID: 32792198 DOI: 10.1016/j.bbrc.2020.07.087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/08/2020] [Accepted: 07/19/2020] [Indexed: 01/25/2023]
Abstract
Olfactory marker protein (OMP), which is expressed abundantly in mature olfactory receptor neurons, operates as a cAMP-binding protein. OMP captures phasic cAMP surges induced by sensory stimuli and punctuates the downstream signalling in the cilia. On the other hand, OMP is also abundant in the soma. At equilibrium, OMP should exhibit association/dissociation reactions with cAMP. To examine the steady-state function of OMP, we expressed OMP in an HEK293 heterologous expression system and measured the activity of cAMP-dependent protein kinase (PKA) using a cAMP response element/luciferase reporter assay. In the presence of OMP, the basal activity level of PKA was elevated to approximately twice as much as that in the absence of OMP. Upon tonic stimulation by membrane-permeable cAMP, the PKA activity increased in a dose-dependent manner and was greater in the presence of OMP at all doses until saturation. These results indicate that OMP, a cytosolic cAMP-binding protein, operates as a cAMP reservoir by increases the basal cAMP concentration and enhances tonic cAMP actions. Together with the previous finding that OMP acutely sequesters cAMP-related responses, these results indicate that OMP can buffer acute surges in cAMP and tonic production, which stabilizes the basal cAMP pool in the long run.
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Affiliation(s)
- Noriyuki Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan.
| | - Kie Nakashima
- Laboratory of Developmental Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshida Hon-machi, Kyoto, 606-8501, Japan
| | - Akiko Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
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38
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Trans-Axonal Signaling in Neural Circuit Wiring. Int J Mol Sci 2020; 21:ijms21145170. [PMID: 32708320 PMCID: PMC7404203 DOI: 10.3390/ijms21145170] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 12/24/2022] Open
Abstract
The development of neural circuits is a complex process that relies on the proper navigation of axons through their environment to their appropriate targets. While axon–environment and axon–target interactions have long been known as essential for circuit formation, communication between axons themselves has only more recently emerged as another crucial mechanism. Trans-axonal signaling governs many axonal behaviors, including fasciculation for proper guidance to targets, defasciculation for pathfinding at important choice points, repulsion along and within tracts for pre-target sorting and target selection, repulsion at the target for precise synaptic connectivity, and potentially selective degeneration for circuit refinement. This review outlines the recent advances in identifying the molecular mechanisms of trans-axonal signaling and discusses the role of axon–axon interactions during the different steps of neural circuit formation.
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39
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Cell type-specific patterned neural activity instructs neural map formation in the mouse olfactory system. Neurosci Res 2020; 170:1-5. [PMID: 32621834 DOI: 10.1016/j.neures.2020.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 11/21/2022]
Abstract
The development of precise neural circuits is initially directed by genetic programming and subsequently refined by neural activity. In the mouse olfactory system, axons from various olfactory sensory neurons expressing the same olfactory receptor converge onto a few spatially invariant glomeruli, generating the olfactory glomerular map in the olfactory bulbs. Using the glomerular map formation as a model, this review summarizes the current understanding of mechanisms underlying topographic map development in the mouse olfactory system and highlights how neural activity instructs the map refinement process.
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40
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Olfactory marker protein captures cAMP produced via Gαs-protein-coupled receptor activation. Biochem Biophys Res Commun 2020; 529:341-346. [PMID: 32703433 DOI: 10.1016/j.bbrc.2020.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 06/05/2020] [Indexed: 11/23/2022]
Abstract
Olfactory marker protein (OMP) labels the matured stage of olfactory receptor neurons (ORN) and has promoted the investigation on the physiology of olfaction. OMP regulates olfactory sensitivity and axonal projection of ORNs, both of which are under the control of the olfactory signaling mediator cAMP. Recently, it has been reported that OMP contains cAMP-binding sites. OMP directly captures the photo-uncaged cAMP in the cytosol and rapidly terminates the olfactory cyclic nucleotide-gated (CNG) channels activity to sharpen the olfactory responses. Here, we investigate the contribution of OMP to cAMP acutely produced via activation of Gαs-protein coupled receptors (GPCR). We expressed OMP and non-desensitizing CNGA2 channels in HEK293T cells together with β1-adrenergic receptors (ADRB1) or photo-sensitive β2-adrenergic receptors (opto-β2). Continuous puff of adrenergic agonist isoproterenol to HEK29T cells with ADRB1 induced the lasting CNGA2 currents in the absence of OMP, while OMP rapidly deactivated the CNGA2 channel activity with residual currents. Photo-activation of opto-β2 in the absence of OMP induced the CNGA2 currents with a prolonged increase, while OMP swiftly deactivated the CNGA2 channels after the initial surge. Therefore, cytosolic OMP rapidly uncouples CNGA2 channels and cAMP-signaling produced via GPCRs in the submembrane compartment.
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41
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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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42
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Zhang Z, Gao X, Zhang Q, Li W. Constitutive activity of a spermine receptor is maintained by a single site in the C-terminal. Biochem Biophys Res Commun 2020; 526:389-395. [PMID: 32222281 DOI: 10.1016/j.bbrc.2020.03.053] [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: 02/17/2020] [Accepted: 03/08/2020] [Indexed: 11/28/2022]
Abstract
Olfactory receptors are G-protein coupled receptors (GPCRs) that enable olfactory epithelia to detect odorants. These GPCRs may also show constitutive activity, which play important roles in the development and responses of odorant receptor neurons. However, little is known about the molecular characteristics that support the constitutive activities in olfactory receptors. Here, we characterize a pair of olfactory receptor orthologs that show similar ligand-dependent activity but different levels of constitutive activity, and elucidate the molecular characteristics that maintain the constitutive activity. Previously, PmTAAR348, a sea lamprey (Petromyzon marinus) olfactory receptor that is activated by the male sex pheromone spermine has been reported. In this study, we identified LmTAAR348 of Northeast Chinese lamprey (Lethenteron morii) as an ortholog of PmTAAR348. When expressed in HEK293T cell lines, both receptors showed similar levels of activation when exposed to spermine. However, the constitutive activity of LmTAAR348 was 100-fold higher than that of PmTAAR348. Using site-directed mutagenesis, we screened all 13 amino acid residues (aa) that differed between the two orthologs and found that a switch in position 340 reversed the constitutive activity levels between LmTAAR348 and PmTAAR348. Mutating the remaining 12 aa did not affect the ligand-dependent or constitutive activation. Moreover, both the ligand-dependent and constitutive activation of TAAR348 are Golf (G protein ⍺ subunit olfactory type) independent. We conclude that a single aa in the C-terminal maintains the constitutive activity in a spermine receptor.
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Affiliation(s)
- Zhe Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Xiang Gao
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Qinghua Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Weming Li
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, 48824, USA.
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43
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Dibattista M, Pifferi S, Menini A, Reisert J. Alzheimer's Disease: What Can We Learn From the Peripheral Olfactory System? Front Neurosci 2020; 14:440. [PMID: 32508565 PMCID: PMC7248389 DOI: 10.3389/fnins.2020.00440] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/09/2020] [Indexed: 01/01/2023] Open
Abstract
The sense of smell has been shown to deteriorate in patients with some neurodegenerative disorders. In Parkinson's disease (PD) and Alzheimer's disease (AD), decreased ability to smell is associated with early disease stages. Thus, olfactory neurons in the nose and olfactory bulb (OB) may provide a window into brain physiology and pathophysiology to address the pathogenesis of neurodegenerative diseases. Because nasal olfactory receptor neurons regenerate throughout life, the olfactory system offers a broad variety of cellular mechanisms that could be altered in AD, including odorant receptor expression, neurogenesis and neurodegeneration in the olfactory epithelium, axonal targeting to the OB, and synaptogenesis and neurogenesis in the OB. This review focuses on pathophysiological changes in the periphery of the olfactory system during the progression of AD in mice, highlighting how the olfactory epithelium and the OB are particularly sensitive to changes in proteins and enzymes involved in AD pathogenesis. Evidence reviewed here in the context of the emergence of other typical pathological changes in AD suggests that olfactory impairments could be used to understand the molecular mechanisms involved in the early phases of the pathology.
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Affiliation(s)
- Michele Dibattista
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari A. Moro, Bari, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
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44
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Nakashima N, Nakashima K, Taura A, Takaku-Nakashima A, Ohmori H, Takano M. Olfactory marker protein directly buffers cAMP to avoid depolarization-induced silencing of olfactory receptor neurons. Nat Commun 2020; 11:2188. [PMID: 32366818 PMCID: PMC7198493 DOI: 10.1038/s41467-020-15917-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/06/2020] [Indexed: 01/05/2023] Open
Abstract
Olfactory receptor neurons (ORNs) use odour-induced intracellular cAMP surge to gate cyclic nucleotide-gated nonselective cation (CNG) channels in cilia. Prolonged exposure to cAMP causes calmodulin-dependent feedback-adaptation of CNG channels and attenuates neural responses. On the other hand, the odour-source searching behaviour requires ORNs to be sensitive to odours when approaching targets. How ORNs accommodate these conflicting aspects of cAMP responses remains unknown. Here, we discover that olfactory marker protein (OMP) is a major cAMP buffer that maintains the sensitivity of ORNs. Upon the application of sensory stimuli, OMP directly captured and swiftly reduced freely available cAMP, which transiently uncoupled downstream CNG channel activity and prevented persistent depolarization. Under repetitive stimulation, OMP-/- ORNs were immediately silenced after burst firing due to sustained depolarization and inactivated firing machinery. Consequently, OMP-/- mice showed serious impairment in odour-source searching tasks. Therefore, cAMP buffering by OMP maintains the resilient firing of ORNs.
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Affiliation(s)
- Noriyuki Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan. .,Department of Physiology and Neurobiology, Faculty of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Kie Nakashima
- Department of Physiology and Neurobiology, Faculty of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, 606-8501, Japan.,Laboratory of Developmental Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshida Hon-machi, Kyoto, 606-8501, Japan
| | - Akiko Taura
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University Hospital, 54 Kawaracho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.,Department of Medical Engineering, Faculty of Health Science, Aino University, 4-5-4 Higashioda, Ibaraki, Osaka, 567-0012, Japan
| | - Akiko Takaku-Nakashima
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan.,Post Graduate Training Program, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Harunori Ohmori
- Department of Physiology and Neurobiology, Faculty of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, 606-8501, Japan.,Department of Physiology, School of Medicine, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa, 920-0293, Japan
| | - Makoto Takano
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
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45
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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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46
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Agonist-independent GPCR activity and receptor-instructed axonal projection in the mouse olfactory system. Future Med Chem 2019; 11:3091-3096. [PMID: 31838900 DOI: 10.4155/fmc-2019-0178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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47
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Qin S, Li Q, Tang C, Tu Y. Optimal compressed sensing strategies for an array of nonlinear olfactory receptor neurons with and without spontaneous activity. Proc Natl Acad Sci U S A 2019; 116:20286-20295. [PMID: 31548382 PMCID: PMC6789560 DOI: 10.1073/pnas.1906571116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
There are numerous different odorant molecules in nature but only a relatively small number of olfactory receptor neurons (ORNs) in brains. This "compressed sensing" challenge is compounded by the constraint that ORNs are nonlinear sensors with a finite dynamic range. Here, we investigate possible optimal olfactory coding strategies by maximizing mutual information between odor mixtures and ORNs' responses with respect to the bipartite odor-receptor interaction network (ORIN) characterized by sensitivities between all odorant-ORN pairs. For ORNs without spontaneous (basal) activity, we find that the optimal ORIN is sparse-a finite fraction of sensitives are zero, and the nonzero sensitivities follow a broad distribution that depends on the odor statistics. We show analytically that sparsity in the optimal ORIN originates from a trade-off between the broad tuning of ORNs and possible interference. Furthermore, we show that the optimal ORIN enhances performances of downstream learning tasks (reconstruction and classification). For ORNs with a finite basal activity, we find that having inhibitory odor-receptor interactions increases the coding capacity and the fraction of inhibitory interactions increases with the ORN basal activity. We argue that basal activities in sensory receptors in different organisms are due to the trade-off between the increase in coding capacity and the cost of maintaining the spontaneous basal activity. Our theoretical findings are consistent with existing experiments and predictions are made to further test our theory. The optimal coding model provides a unifying framework to understand the peripheral olfactory systems across different organisms.
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Affiliation(s)
- Shanshan Qin
- Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Qianyi Li
- Integrated Science Program, Yuanpei College, Peking University, Beijing 100871, China
| | - Chao Tang
- Center for Quantitative Biology, Peking University, Beijing 100871, China;
- School of Physics, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yuhai Tu
- Physical Sciences Department, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598
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48
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Vaddadi N, Iversen K, Raja R, Phen A, Brignall A, Dumontier E, Cloutier JF. Kirrel2 is differentially required in populations of olfactory sensory neurons for the targeting of axons in the olfactory bulb. Development 2019; 146:dev.173310. [PMID: 31142543 DOI: 10.1242/dev.173310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 05/15/2019] [Indexed: 01/25/2023]
Abstract
The formation of olfactory maps in the olfactory bulb (OB) is crucial for the control of innate and learned mouse behaviors. Olfactory sensory neurons (OSNs) expressing a specific odorant receptor project axons into spatially conserved glomeruli within the OB and synapse onto mitral cell dendrites. Combinatorial expression of members of the Kirrel family of cell adhesion molecules has been proposed to regulate OSN axonal coalescence; however, loss-of-function experiments have yet to establish their requirement in this process. We examined projections of several OSN populations in mice that lacked either Kirrel2 alone, or both Kirrel2 and Kirrel3. Our results show that Kirrel2 and Kirrel3 are dispensable for the coalescence of MOR1-3-expressing OSN axons to the most dorsal region (DI) of the OB. In contrast, loss of Kirrel2 caused MOR174-9- and M72-expressing OSN axons, projecting to the DII region, to target ectopic glomeruli. Our loss-of-function approach demonstrates that Kirrel2 is required for axonal coalescence in subsets of OSNs that project axons to the DII region and reveals that Kirrel2/3-independent mechanisms also control OSN axonal coalescence in certain regions of the OB.
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Affiliation(s)
- Neelima Vaddadi
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Katrine Iversen
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Reesha Raja
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada
| | - Alina Phen
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Alexandra Brignall
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Emilie Dumontier
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada
| | - Jean-François Cloutier
- Montreal Neurological Institute, Centre for Neuronal Survival, 3801 University, Montréal, Québec H3A 2B4, Canada .,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec H3A 2B4, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
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49
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Nakashima A, Ihara N, Shigeta M, Kiyonari H, Ikegaya Y, Takeuchi H. Structured spike series specify gene expression patterns for olfactory circuit formation. Science 2019; 365:science.aaw5030. [PMID: 31171707 DOI: 10.1126/science.aaw5030] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/23/2019] [Indexed: 12/21/2022]
Abstract
Neural circuits emerge through the interplay of genetic programming and activity-dependent processes. During the development of the mouse olfactory map, axons segregate into distinct glomeruli in an olfactory receptor (OR)-dependent manner. ORs generate a combinatorial code of axon-sorting molecules whose expression is regulated by neural activity. However, it remains unclear how neural activity induces OR-specific expression patterns of axon-sorting molecules. We found that the temporal patterns of spontaneous neuronal spikes were not spatially organized but were correlated with the OR types. Receptor substitution experiments demonstrated that ORs determine spontaneous activity patterns. Moreover, optogenetically differentiated patterns of neuronal activity induced specific expression of the corresponding axon-sorting molecules and regulated axonal segregation. Thus, OR-dependent temporal patterns of spontaneous activity play instructive roles in generating the combinatorial code of axon-sorting molecules during olfactory map formation.
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Affiliation(s)
- Ai Nakashima
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Naoki Ihara
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
| | - Mayo Shigeta
- Laboratory for Animal Resource Development, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0047, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resource Development, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0047, Japan.,Laboratory for Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima Minami-machi, Chuo-ku, Kobe 650-0047, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan.,Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka 565-0871, Japan
| | - Haruki Takeuchi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan. .,Social Cooperation Program of Evolutional Chemical Safety Assessment System, LECSAS, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
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50
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Contribution of individual olfactory receptors to odor-induced attractive or aversive behavior in mice. Nat Commun 2019; 10:209. [PMID: 30643144 PMCID: PMC6331590 DOI: 10.1038/s41467-018-07940-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 12/05/2018] [Indexed: 11/17/2022] Open
Abstract
Odorants are recognized by multiple olfactory receptors (ORs) and induce innate behaviors like attraction or aversion via olfactory system in mice. However, a role of an individual OR is unclear. Muscone is recognized by a few ORs including MOR215–1 and MOR214–3, and attracts male mice. Odor preference tests using MOR215–1 knockout mice revealed that MOR215–1 and other OR(s), possibly including MOR214–3, are involved in the attraction. (Z)-5-tetradecen-1-ol (Z5–14:OH) activates ~3 ORs, including Olfr288, and evokes attraction at low levels but aversion at higher levels. Olfr288 knockout mice show no attraction but aversion, suggesting Olfr288 is involved in preference for Z5–14:OH, whereas activation of other low-affinity Z5–14:OH receptors evokes aversion. Each OR appears to send a signal to a neural circuit that possesses distinct valence, leading to a certain behavior. The final output behavior with multiple ORs stimulation is determined by summation (addition or competition) of valences coded by activated ORs. Recent evidence suggests that some olfactory receptor types (OR) may be indispensable to elicit certain innate odor-evoked behaviors. Here, the authors report that eliminating a single OR from the odor-activated ensemble leads to significant changes in odor perception and the evoked behavioral response.
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