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Hooi YT, Fu TL, Tan SH, Ong KC, Tan CY, Wong KT. Neuroinvasion via Peripheral Nerves in Epidemic Viral Encephalitis Caused by Enterovirus, Orthoflavivirus and SARS-Coronavirus. Neuropathol Appl Neurobiol 2025; 51:e70005. [PMID: 39989030 DOI: 10.1111/nan.70005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Revised: 01/14/2025] [Accepted: 02/12/2025] [Indexed: 02/25/2025]
Abstract
Pathogens invade the central nervous system (CNS) and cause infections either through the haematogenous route or via peripheral nerves. Neuroinvasion via peripheral nerves, involving spinal or cranial somatic nerves, is well-established for certain viral encephalitides such as rabies, herpes simplex encephalitis, and poliomyelitis. Advances in understanding emerging and re-emerging viruses that cause epidemic CNS infections have highlighted the growing importance of peripheral nerve pathways in viral neuroinvasion. This review focuses on epidemic viral encephalitides caused by three groups of RNA viruses, viz., enteroviruses (enterovirus A71 and enterovirus D68), orthoflaviviruses (West Nile virus and Japanese encephalitis virus), and severe acute respiratory syndrome coronaviruses (mainly severe acute respiratory coronavirus-2). We examine evidence supporting the hypothesis that peripheral nerve viral transmission may play an increasingly significant if not more critical role than the haematogenous route in neuroinvasion.
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Affiliation(s)
- Yuan Teng Hooi
- Infection and Immunity Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
| | - Tzeh Long Fu
- Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Soon Hao Tan
- Department of Biomedical Sciences, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kien Chai Ong
- Department of Biomedical Sciences, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chee Yang Tan
- MBBS Class of 2017/2022, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kum Thong Wong
- Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia
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2
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Lipshutz A, Saltz V, Anderson KR, Manganaro A, Dumitriu D. A localized tracing technique to explore intra-amygdala functional and structural correlates of individual variability in behavioral response. Front Mol Neurosci 2025; 18:1347539. [PMID: 39916773 PMCID: PMC11794228 DOI: 10.3389/fnmol.2025.1347539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/08/2025] [Indexed: 02/09/2025] Open
Abstract
Introduction The neurobiological basis for individual variability in behavioral responses to stimuli remains poorly understood. Probing the neural substrates that underlie individual variability in stress responses may open the door for preventive approaches that use biological markers to identify at-risk populations. New developments of viral neuronal tracing tools have led to a recent increase in studies on long range circuits and their functional role in stress responses and social behavior. While these studies are necessary to untangle largescale connectivity, most social behaviors are mediated and fine-tuned by local subregional circuitry. Methods In order to probe this local, interregional connectivity, we present a new combination of a neuronal tracing system with immediate early gene immunohistochemistry for examining structural and functional connectivity within the same animal. Specifically, we combine a retrograde transsynaptic rabies tracing system with cFos colocalization immediately after an acute stressor to elucidate local structural and stress-activated connectivity within the amygdala complex in female and male mice. Results and discussion We show how specific structural and functional connections can predict individual variability along a spectrum of social approach/avoidance following acute social defeat stress. We demonstrate how our robust method can be used to elucidate structural and functional differences in local connectivity that mediate individual variability in behavioral response.
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Affiliation(s)
- Allie Lipshutz
- Division of Developmental Neuroscience, Department of Psychiatry, Columbia University, New York, NY, United States
- Division for Child and Adolescent Health, Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, United States
| | - Victoria Saltz
- Division of Developmental Neuroscience, Department of Psychiatry, Columbia University, New York, NY, United States
- Division for Child and Adolescent Health, Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, United States
- Zuckerman Institute, Columbia University, New York, NY, United States
| | - Kristin R. Anderson
- Division of Developmental Neuroscience, Department of Psychiatry, Columbia University, New York, NY, United States
- Division for Child and Adolescent Health, Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, United States
| | - Alessia Manganaro
- Division of Developmental Neuroscience, Department of Psychiatry, Columbia University, New York, NY, United States
- Division for Child and Adolescent Health, Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, United States
| | - Dani Dumitriu
- Division of Developmental Neuroscience, Department of Psychiatry, Columbia University, New York, NY, United States
- Division for Child and Adolescent Health, Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, United States
- Zuckerman Institute, Columbia University, New York, NY, United States
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3
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Kembou-Ringert JE, Hotio FN, Steinhagen D, Thompson KD, Surachetpong W, Rakus K, Daly JM, Goonawardane N, Adamek M. Knowns and unknowns of TiLV-associated neuronal disease. Virulence 2024; 15:2329568. [PMID: 38555518 PMCID: PMC10984141 DOI: 10.1080/21505594.2024.2329568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/07/2024] [Indexed: 04/02/2024] Open
Abstract
Tilapia Lake Virus (TiLV) is associated with pathological changes in the brain of infected fish, but the mechanisms driving the virus's neuropathogenesis remain poorly characterized. TiLV establishes a persistent infection in the brain of infected fish even when the virus is no longer detectable in the peripheral organs, rendering therapeutic interventions and disease management challenging. Moreover, the persistence of the virus in the brain may pose a risk for viral reinfection and spread and contribute to ongoing tissue damage and neuroinflammatory processes. In this review, we explore TiLV-associated neurological disease. We discuss the possible mechanism(s) used by TiLV to enter the central nervous system (CNS) and examine TiLV-induced neuroinflammation and brain immune responses. Lastly, we discuss future research questions and knowledge gaps to be addressed to significantly advance this field.
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Affiliation(s)
- Japhette E. Kembou-Ringert
- Department of infection, immunity and Inflammation, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Fortune N. Hotio
- Department of Animal Biology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Dieter Steinhagen
- Fish Disease Research Unit, Institute for parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Kim D. Thompson
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, UK
| | - Win Surachetpong
- Department of Veterinary Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Krzysztof Rakus
- Department of Evolutionary Immunology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, Poland
| | - Janet M. Daly
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
| | - Niluka Goonawardane
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Mikolaj Adamek
- Fish Disease Research Unit, Institute for parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
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4
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Worthy AE, Anderson JT, Lane AR, Gomez-Perez LJ, Wang AA, Griffith RW, Rivard AF, Bikoff JB, Alvarez FJ. Spinal V1 inhibitory interneuron clades differ in birthdate, projections to motoneurons, and heterogeneity. eLife 2024; 13:RP95172. [PMID: 39607843 PMCID: PMC11604222 DOI: 10.7554/elife.95172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2024] Open
Abstract
Spinal cord interneurons play critical roles shaping motor output, but their precise identity and connectivity remain unclear. Focusing on the V1 interneuron cardinal class we defined four major V1 subsets in the mouse according to neurogenesis, genetic lineage-tracing, synaptic output to motoneurons, and synaptic inputs from muscle afferents. Sequential neurogenesis delineates different V1 subsets: two early born (Renshaw and Pou6f2) and two late born (Foxp2 and Sp8). Early born Renshaw cells and late born Foxp2-V1 interneurons are tightly coupled to motoneurons, while early born Pou6f2-V1 and late born Sp8-V1 interneurons are not, indicating that timing of neurogenesis does not correlate with motoneuron targeting. V1 clades also differ in cell numbers and diversity. Lineage labeling shows that the Foxp2-V1 clade contains over half of all V1 interneurons, provides the largest inhibitory input to motoneuron cell bodies, and includes subgroups that differ in birthdate, location, and proprioceptive input. Notably, one Foxp2-V1 subgroup, defined by postnatal Otp expression, is positioned near the LMC and receives substantial input from proprioceptors, consistent with an involvement in reciprocal inhibitory pathways. Combined tracing of ankle flexor sensory afferents and interneurons monosynaptically connected to ankle extensors confirmed placement of Foxp2-V1 interneurons in reciprocal inhibitory pathways. Our results validate previously proposed V1 clades as unique functional subtypes that differ in circuit placement, with Foxp2-V1 cells forming the most heterogeneous subgroup. We discuss how V1 organizational diversity enables understanding of their roles in motor control, with implications for their diverse ontogenetic and phylogenetic origins.
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Affiliation(s)
- Andrew E Worthy
- Department of Physiology, Emory University School of MedicineAtlantaUnited States
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Joanna T Anderson
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Alicia R Lane
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Laura J Gomez-Perez
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Anthony A Wang
- Department of Physiology, Emory University School of MedicineAtlantaUnited States
| | - Ronald W Griffith
- Department of Physiology, Emory University School of MedicineAtlantaUnited States
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Andre F Rivard
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
| | - Jay B Bikoff
- Department of Developmental Neurobiology, St Jude Children’s Research HospitalMemphisUnited States
| | - Francisco J Alvarez
- Department of Physiology, Emory University School of MedicineAtlantaUnited States
- Department of Cell Biology, Emory University School of MedicineAtlantaUnited States
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5
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Worthy AE, Anderson JT, Lane AR, Gomez-Perez L, Wang AA, Griffith RW, Rivard AF, Bikoff JB, Alvarez FJ. Spinal V1 inhibitory interneuron clades differ in birthdate, projections to motoneurons, and heterogeneity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.29.569270. [PMID: 38076820 PMCID: PMC10705425 DOI: 10.1101/2023.11.29.569270] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Spinal cord interneurons play critical roles shaping motor output, but their precise identity and connectivity remain unclear. Focusing on the V1 interneuron cardinal class we defined four major V1 subsets according to neurogenesis timing, genetic lineage-tracing, synaptic output to motoneurons, and synaptic inputs from muscle afferents. Birthdate delineates two early born (Renshaw and Pou6f2) and two late born (Foxp2 and Sp8) V1 clades, showing that sequential neurogenesis produces different V1 subsets. Early born Renshaw cells and late born Foxp2-V1 interneurons are tightly coupled to motoneurons, while early born Pou6f2-V1 and late born Sp8-V1 interneurons are not, indicating that timing of neurogenesis does not correlate with motoneuron targeting. V1 clades also differ in cell numbers and diversity. Lineage labeling shows that the Foxp2-V1 clade contains over half of all V1 interneurons, provides the largest inhibitory input to motoneuron cell bodies and includes subgroups that differ in birthdate, location, and proprioceptive input. Notably, one Foxp2-V1 subgroup, defined by postnatal Otp expression is positioned near the lateral motor column and receives substantial input from proprioceptors, consistent with an involvement in reciprocal inhibitory pathways. Combined tracing of ankle flexor sensory afferents and interneurons monosynaptically connected to ankle extensors confirmed placement of Foxp2-V1 interneurons in reciprocal inhibitory pathways. Our results validate previously proposed V1 clades as unique functional subtypes that differ in circuit placement, with Foxp2-V1 cells forming the most heterogeneous subgroup. We discuss how V1 organizational diversity enables understanding of their roles in motor control, with implications for their diverse ontogenetic and phylogenetic origins. SIGNIFICANCE STATEMENT The complexity of spinal interneuron diversity and circuit organization represents a challenge to understand neural control of movement in normal adults as well as during motor development and in disease. Inhibitory interneurons are a core element of these spinal circuits. V1 interneurons comprise the largest group of inhibitory interneurons in the ventral horn, and their organization remains unclear. Here we present a comprehensive examination of V1 subtypes according to neurogenesis, placement in spinal motor circuits, and motoneuron synaptic targeting. V1 diversity increases during evolution from axial-swimming fishes to limb-based mammalian terrestrial locomotion. This increased diversity is reflected in the size and heterogeneity of the Foxp2-V1 clade, a group closely associated with limb motor pools. We show that Foxp2-V1 interneurons establish the densest direct inhibitory input to motoneurons, especially on cell bodies. These findings are particularly significant because recent studies have shown that motor neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) affect inhibitory V1 synapses on motoneuron cell bodies and Foxp2-V1 interneurons themselves in the earliest stages of pathology.
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Huang J, Wang P, Wang W, Wei J, Yang L, Liu Z, Li G. Using Electrical Muscle Stimulation to Enhance Electrophysiological Performance of Agonist-Antagonist Myoneural Interface. Bioengineering (Basel) 2024; 11:904. [PMID: 39329646 PMCID: PMC11444137 DOI: 10.3390/bioengineering11090904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 09/02/2024] [Accepted: 09/04/2024] [Indexed: 09/28/2024] Open
Abstract
The agonist-antagonist myoneural interface (AMI), a surgical method to reinnervate physiologically-relevant proprioceptive feedback for control of limb prostheses, has demonstrated the ability to provide natural afferent sensations for limb amputees when actuating their prostheses. Following AMI surgery, one potential challenge is atrophy of the disused muscles, which would weaken the reinnervation efficacy of AMI. It is well known that electrical muscle stimulus (EMS) can reduce muscle atrophy. In this study, we conducted an animal investigation to explore whether the EMS can significantly improve the electrophysiological performance of AMI. AMI surgery was performed in 14 rats, in which the distal tendons of bilateral solei donors were connected and positioned on the surface of the left biceps femoris. Subsequently, the left tibial nerve and the common peroneus nerve were sutured onto the ends of the connected donor solei. Two stimulation electrodes were affixed onto the ends of the donor solei for EMS delivery. The AMI rats were randomly divided into two groups. One group received the EMS treatment (designated as EMS_on) regularly for eight weeks and another received no EMS (designated as EMS_off). Two physiological parameters, nerve conduction velocity (NCV) and motor unit number, were derived from the electrically evoked compound action potential (CAP) signals to assess the electrophysiological performance of AMI. Our experimental results demonstrated that the reinnervated muscles of the EMS_on group generated higher CAP signals in comparison to the EMS_off group. Both NCV and motor unit number were significantly elevated in the EMS_on group. Moreover, the EMS_on group displayed statistically higher CAP signals on the indirectly activated proprioceptive afferents than the EMS_off group. These findings suggested that EMS treatment would be promising in enhancing the electrophysiological performance and facilitating the reinnervation process of AMI.
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Affiliation(s)
- Jianping Huang
- Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences, Shenzhen 518055, China; (J.H.); (W.W.); (J.W.); (L.Y.)
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100864, China
| | - Ping Wang
- Biomedical Sensing Engineering and Technology Research Center, Shandong University, Jinan 250000, China;
| | - Wei Wang
- Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences, Shenzhen 518055, China; (J.H.); (W.W.); (J.W.); (L.Y.)
| | - Jingjing Wei
- Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences, Shenzhen 518055, China; (J.H.); (W.W.); (J.W.); (L.Y.)
| | - Lin Yang
- Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences, Shenzhen 518055, China; (J.H.); (W.W.); (J.W.); (L.Y.)
| | - Zhiyuan Liu
- Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences, Shenzhen 518055, China; (J.H.); (W.W.); (J.W.); (L.Y.)
- Biomedical Sensing Engineering and Technology Research Center, Shandong University, Jinan 250000, China;
| | - Guanglin Li
- Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences, Shenzhen 518055, China; (J.H.); (W.W.); (J.W.); (L.Y.)
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100864, China
- The SIAT Branch, Shenzhen Institute of Artificial Intelligence and Robotics for Society, Shenzhen 518055, China
- Shandong Zhongke Advanced Technology Co., Ltd., Jinan 250000, China
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7
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Espinosa F, Pop IV, Lai HC. Electrophysiological Properties of Proprioception-Related Neurons in the Intermediate Thoracolumbar Spinal Cord. eNeuro 2024; 11:ENEURO.0331-23.2024. [PMID: 38627062 PMCID: PMC11055654 DOI: 10.1523/eneuro.0331-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 04/03/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Proprioception, the sense of limb and body position, is required to produce accurate and precise movements. Proprioceptive sensory neurons transmit muscle length and tension information to the spinal cord. The function of excitatory neurons in the intermediate spinal cord, which receive this proprioceptive information, remains poorly understood. Using genetic labeling strategies and patch-clamp techniques in acute spinal cord preparations in mice, we set out to uncover how two sets of spinal neurons, Clarke's column (CC) and Atoh1-lineage neurons, respond to electrical activity and how their inputs are organized. Both sets of neurons are located in close proximity in laminae V-VII of the thoracolumbar spinal cord and have been described to receive proprioceptive signals. We find that a majority of CC neurons have a tonic-firing type and express a distinctive hyperpolarization-activated current (Ih). Atoh1-lineage neurons, which cluster into two spatially distinct populations, are mostly a fading-firing type and display similar electrophysiological properties to each other, possibly due to their common developmental lineage. Finally, we find that CC neurons respond to stimulation of lumbar dorsal roots, consistent with prior knowledge that CC neurons receive hindlimb proprioceptive information. In contrast, using a combination of electrical stimulation, optogenetic stimulation, and transsynaptic rabies virus tracing, we find that Atoh1-lineage neurons receive heterogeneous, predominantly local thoracic inputs that include parvalbumin-lineage sensory afferents and local interneuron presynaptic inputs. Altogether, we find that CC and Atoh1-lineage neurons have distinct membrane properties and sensory input organization, representing different subcircuit modes of proprioceptive information processing.
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Affiliation(s)
- Felipe Espinosa
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas 75390
| | - Iliodora V Pop
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas 75390
| | - Helen C Lai
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas 75390
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8
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Velica A, Kullander K. A flowchart for adequate controls in virus-based monosynaptic tracing experiments identified Cre-independent leakage of the TVA receptor in RΦGT mice. BMC Neurosci 2024; 25:9. [PMID: 38383317 PMCID: PMC10882902 DOI: 10.1186/s12868-024-00848-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/29/2024] [Indexed: 02/23/2024] Open
Abstract
BACKGROUND A pseudotyped modified rabies virus lacking the rabies glycoprotein (G-protein), which is crucial for transsynaptic spread, can be used for monosynaptic retrograde tracing. By coupling the pseudotyped virus with transgene expression of the G-protein and the avian leukosis and sarcoma virus subgroup A receptor (TVA), which is necessary for cell entry of the virus, researchers can investigate specific neuronal populations. Responder mouse lines, like the RΦGT mouse line, carry the genes encoding the G-protein and TVA under Cre-dependent expression. These mouse lines are valuable tools because they reduce the number of viral injections needed compared to when using helper viruses. Since RΦGT mice do not express Cre themselves, introducing the pseudotyped rabies virus into their brain should not result in viral cell entry or spread. RESULTS We present a straightforward flowchart for adequate controls in tracing experiments, which we employed to demonstrate Cre-independent expression of TVA in RΦGT mice. CONCLUSIONS Our observations revealed TVA leakage, indicating that RΦGT mice should be used with caution for transgene expression of TVA. Inaccurate tracing outcomes may occur if TVA is expressed in the absence of Cre since background leakage leads to nonspecific cell entry. Moreover, conducting appropriate control experiments can identify the source of potential caveats in virus-based neuronal tracing experiments.
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Affiliation(s)
- Anna Velica
- Department of Immunology, Genetics and Pathology, Uppsala University, 815, Husargatan 3, Uppsala, 751 08, Sweden.
| | - Klas Kullander
- Department of Immunology, Genetics and Pathology, Uppsala University, 815, Husargatan 3, Uppsala, 751 08, Sweden
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Jin L, Sullivan HA, Zhu M, Lavin TK, Matsuyama M, Fu X, Lea NE, Xu R, Hou Y, Rutigliani L, Pruner M, Babcock KR, Ip JPK, Hu M, Daigle TL, Zeng H, Sur M, Feng G, Wickersham IR. Long-term labeling and imaging of synaptically connected neuronal networks in vivo using double-deletion-mutant rabies viruses. Nat Neurosci 2024; 27:373-383. [PMID: 38212587 PMCID: PMC10849964 DOI: 10.1038/s41593-023-01545-8] [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: 12/16/2021] [Accepted: 12/05/2023] [Indexed: 01/13/2024]
Abstract
Rabies-virus-based monosynaptic tracing is a widely used technique for mapping neural circuitry, but its cytotoxicity has confined it primarily to anatomical applications. Here we present a second-generation system for labeling direct inputs to targeted neuronal populations with minimal toxicity, using double-deletion-mutant rabies viruses. Viral spread requires expression of both deleted viral genes in trans in postsynaptic source cells. Suppressing this expression with doxycycline following an initial period of viral replication reduces toxicity to postsynaptic cells. Longitudinal two-photon imaging in vivo indicated that over 90% of both presynaptic and source cells survived for the full 12-week course of imaging. Ex vivo whole-cell recordings at 5 weeks postinfection showed that the second-generation system perturbs input and source cells much less than the first-generation system. Finally, two-photon calcium imaging of labeled networks of visual cortex neurons showed that their visual response properties appeared normal for 10 weeks, the longest we followed them.
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Affiliation(s)
- Lei Jin
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Lingang Laboratory, Shanghai, China
| | - Heather A Sullivan
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mulangma Zhu
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Thomas K Lavin
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Makoto Matsuyama
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xin Fu
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nicholas E Lea
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ran Xu
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - YuanYuan Hou
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Luca Rutigliani
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Maxwell Pruner
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kelsey R Babcock
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jacque Pak Kan Ip
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ming Hu
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | | | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Guoping Feng
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ian R Wickersham
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
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10
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Eleftheriadis PE, Pothakos K, Sharples SA, Apostolou PE, Mina M, Tetringa E, Tsape E, Miles GB, Zagoraiou L. Peptidergic modulation of motor neuron output via CART signaling at C bouton synapses. Proc Natl Acad Sci U S A 2023; 120:e2300348120. [PMID: 37733738 PMCID: PMC10523464 DOI: 10.1073/pnas.2300348120] [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: 01/17/2023] [Accepted: 07/17/2023] [Indexed: 09/23/2023] Open
Abstract
The intensity of muscle contraction, and therefore movement vigor, needs to be adaptable to enable complex motor behaviors. This can be achieved by adjusting the properties of motor neurons, which form the final common pathway for all motor output from the central nervous system. Here, we identify roles for a neuropeptide, cocaine- and amphetamine-regulated transcript (CART), in the control of movement vigor. We reveal distinct but parallel mechanisms by which CART and acetylcholine, both released at C bouton synapses on motor neurons, selectively amplify the output of subtypes of motor neurons that are recruited during intense movement. We find that mice with broad genetic deletion of CART or selective elimination of acetylcholine from C boutons exhibit deficits in behavioral tasks that require higher levels of motor output. Overall, these data uncover spinal modulatory mechanisms that control movement vigor to support movements that require a high degree of muscle force.
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Affiliation(s)
| | - Konstantinos Pothakos
- Center of Basic Research, Biomedical Research Foundation Academy of Athens, Athens11527, Greece
| | - Simon A. Sharples
- School of Psychology and Neuroscience, University of St. Andrews, St. AndrewsKY16 9JP, United Kingdom
| | - Panagiota E. Apostolou
- Center of Basic Research, Biomedical Research Foundation Academy of Athens, Athens11527, Greece
| | - Maria Mina
- Center of Basic Research, Biomedical Research Foundation Academy of Athens, Athens11527, Greece
| | - Efstathia Tetringa
- Center of Basic Research, Biomedical Research Foundation Academy of Athens, Athens11527, Greece
| | - Eirini Tsape
- Center of Basic Research, Biomedical Research Foundation Academy of Athens, Athens11527, Greece
| | - Gareth B. Miles
- School of Psychology and Neuroscience, University of St. Andrews, St. AndrewsKY16 9JP, United Kingdom
| | - Laskaro Zagoraiou
- Center of Basic Research, Biomedical Research Foundation Academy of Athens, Athens11527, Greece
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11
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Maurer L, Brown M, Saggi T, Cardiges A, Kolarcik CL. Hindlimb muscle representations in mouse motor cortex defined by viral tracing. Front Neuroanat 2023; 17:965318. [PMID: 37303816 PMCID: PMC10248224 DOI: 10.3389/fnana.2023.965318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Introduction Descending pathways from the cortex to the spinal cord are involved in the control of natural movement. Although mice are widely used to study the neurobiology of movement and as models of neurodegenerative disease, an understanding of motor cortical organization is lacking, particularly for hindlimb muscles. Methods In this study, we used the retrograde transneuronal transport of rabies virus to compare the organization of descending cortical projections to fast- and slow-twitch hindlimb muscles surrounding the ankle joint in mice. Results Although the initial stage of virus transport from the soleus muscle (predominantly slow-twitch) appeared to be more rapid than that associated with the tibialis anterior muscle (predominantly fast-twitch), the rate of further transport of virus to cortical projection neurons in layer V was equivalent for the two injected muscles. After appropriate survival times, dense concentrations of layer V projection neurons were identified in three cortical areas: the primary motor cortex (M1), secondary motor cortex (M2), and primary somatosensory cortex (S1). Discussion The origin of the cortical projections to each of the two injected muscles overlapped almost entirely within these cortical areas. This organization suggests that cortical projection neurons maintain a high degree of specificity; that is, even when cortical projection neurons are closely located, each neuron could have a distinct functional role (controlling fast- versus slow-twitch and/or extensor versus flexor muscles). Our results represent an important addition to the understanding of the mouse motor system and lay the foundation for future studies investigating the mechanisms underlying motor system dysfunction and degeneration in diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy.
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Affiliation(s)
- Lauren Maurer
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Maia Brown
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Tamandeep Saggi
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Alexia Cardiges
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Christi L. Kolarcik
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
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12
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Vieillard J, Franck MCM, Hartung S, Jakobsson JET, Ceder MM, Welsh RE, Lagerström MC, Kullander K. Adult spinal Dmrt3 neurons receive direct somatosensory inputs from ipsi- and contralateral primary afferents and from brainstem motor nuclei. J Comp Neurol 2023; 531:5-24. [PMID: 36214727 PMCID: PMC9828095 DOI: 10.1002/cne.25405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 01/12/2023]
Abstract
In the spinal cord, sensory-motor circuits controlling motor activity are situated in the dorso-ventral interface. The neurons identified by the expression of the transcription factor Doublesex and mab-3 related transcription factor 3 (Dmrt3) have previously been associated with the coordination of locomotion in horses (Equus caballus, Linnaeus, 1758), mice (Mus musculus, Linnaeus, 1758), and zebrafish (Danio rerio, F. Hamilton, 1822). Based on earlier studies, we hypothesized that, in mice, these neurons may be positioned to receive sensory and central inputs to relay processed commands to motor neurons. Thus, we investigated the presynaptic inputs to spinal Dmrt3 neurons using monosynaptic retrograde replication-deficient rabies tracing. The analysis showed that lumbar Dmrt3 neurons receive inputs from intrasegmental neurons, and intersegmental neurons from the cervical, thoracic, and sacral segments. Some of these neurons belong to the excitatory V2a interneurons and to plausible Renshaw cells, defined by the expression of Chx10 and calbindin, respectively. We also found that proprioceptive primary sensory neurons of type Ia2, Ia3, and Ib, defined by the expression of calbindin, calretinin, and Brn3c, respectively, provide presynaptic inputs to spinal Dmrt3 neurons. In addition, we demonstrated that Dmrt3 neurons receive inputs from brain areas involved in motor regulation, including the red nucleus, primary sensory-motor cortex, and pontine nuclei. In conclusion, adult spinal Dmrt3 neurons receive inputs from motor-related brain areas as well as proprioceptive primary sensory neurons and have been shown to connect directly to motor neurons. Dmrt3 neurons are thus positioned to provide sensory-motor control and their connectivity is suggestive of the classical reflex pathways present in the spinal cord.
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Affiliation(s)
- Jennifer Vieillard
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Marina C. M. Franck
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden,Present address: Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Sunniva Hartung
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Jon E. T. Jakobsson
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Mikaela M. Ceder
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Robert E. Welsh
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Malin C. Lagerström
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | - Klas Kullander
- Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
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13
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Berki B, Sacher F, Fages A, Tschopp P, Luxey M. A method to investigate muscle target-specific transcriptional signatures of single motor neurons. Dev Dyn 2023; 252:208-219. [PMID: 35705847 PMCID: PMC10084336 DOI: 10.1002/dvdy.507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Motor neurons in the vertebrate spinal cord have long served as a paradigm to study the transcriptional logic of cell type specification and differentiation. At limb levels, pool-specific transcriptional signatures first restrict innervation to only one particular muscle in the periphery, and get refined, once muscle connection has been established. Accordingly, to study the transcriptional dynamics and specificity of the system, a method for establishing muscle target-specific motor neuron transcriptomes would be required. RESULTS To investigate target-specific transcriptional signatures of single motor neurons, here we combine ex-ovo retrograde axonal labeling in mid-gestation chicken embryos with manual isolation of individual fluorescent cells and Smart-seq2 single-cell RNA-sequencing. We validate our method by injecting the dorsal extensor metacarpi radialis and ventral flexor digiti quarti wing muscles and harvesting a total of 50 fluorescently labeled cells, in which we detect up to 12,000 transcribed genes. Additionally, we present visual cues and cDNA metrics predictive of sequencing success. CONCLUSIONS Our method provides a unique approach to study muscle target-specific motor neuron transcriptomes at a single-cell resolution. We anticipate that our method will provide key insights into the transcriptional logic underlying motor neuron pool specialization and proper neuromuscular circuit assembly and refinement.
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Affiliation(s)
- Bianka Berki
- DUW Zoology, University of Basel, Basel, Switzerland
| | - Fabio Sacher
- DUW Zoology, University of Basel, Basel, Switzerland
| | - Antoine Fages
- DUW Zoology, University of Basel, Basel, Switzerland
| | | | - Maëva Luxey
- DUW Zoology, University of Basel, Basel, Switzerland
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14
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Ronzano R, Skarlatou S, Barriga BK, Bannatyne BA, Bhumbra GS, Foster JD, Moore JD, Lancelin C, Pocratsky AM, Özyurt MG, Smith CC, Todd AJ, Maxwell DJ, Murray AJ, Pfaff SL, Brownstone RM, Zampieri N, Beato M. Spinal premotor interneurons controlling antagonistic muscles are spatially intermingled. eLife 2022; 11:e81976. [PMID: 36512397 PMCID: PMC9844990 DOI: 10.7554/elife.81976] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 12/11/2022] [Indexed: 12/15/2022] Open
Abstract
Elaborate behaviours are produced by tightly controlled flexor-extensor motor neuron activation patterns. Motor neurons are regulated by a network of interneurons within the spinal cord, but the computational processes involved in motor control are not fully understood. The neuroanatomical arrangement of motor and premotor neurons into topographic patterns related to their controlled muscles is thought to facilitate how information is processed by spinal circuits. Rabies retrograde monosynaptic tracing has been used to label premotor interneurons innervating specific motor neuron pools, with previous studies reporting topographic mediolateral positional biases in flexor and extensor premotor interneurons. To more precisely define how premotor interneurons contacting specific motor pools are organized, we used multiple complementary viral-tracing approaches in mice to minimize systematic biases associated with each method. Contrary to expectations, we found that premotor interneurons contacting motor pools controlling flexion and extension of the ankle are highly intermingled rather than segregated into specific domains like motor neurons. Thus, premotor spinal neurons controlling different muscles process motor instructions in the absence of clear spatial patterns among the flexor-extensor circuit components.
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Affiliation(s)
- Remi Ronzano
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | | | - Bianca K Barriga
- Gene Expression Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
- Biological Sciences Graduate Program, University of California, San DiegoSan DiegoUnited States
| | - B Anne Bannatyne
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUnited Kingdom
| | - Gardave Singh Bhumbra
- Department of Neuroscience Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Joshua D Foster
- Department of Neuroscience Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Jeffrey D Moore
- Howard Hughes Medical Institute and Department of Molecular and Cellular Biology, Center for Brain Science, Harvard UniversityCambridgeUnited States
| | - Camille Lancelin
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | - Amanda M Pocratsky
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | | | - Calvin Chad Smith
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUnited Kingdom
| | - David J Maxwell
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUnited Kingdom
| | - Andrew J Murray
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College LondonLondonUnited Kingdom
| | - Samuel L Pfaff
- Gene Expression Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
| | - Robert M Brownstone
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | | | - Marco Beato
- Department of Neuroscience Physiology and Pharmacology, University College LondonLondonUnited Kingdom
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15
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Jankowska E. Basic principles of processing of afferent information by spinal interneurons. J Neurophysiol 2022; 128:689-695. [PMID: 36043802 DOI: 10.1152/jn.00344.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Integrative functions of spinal interneurons are well recognized but the relative role of different interneuronal populations in this process continues to be investigated. It therefore appeared useful to review the principles of integration of afferent information by the interneurons analyzed so far as these principles should apply also to those remaining to be analyzed. Considering the results of both functional and morphological studies of spinal interneurons and of the morphology and immunochemistry of afferent fibres that provide input to them, the following five basic principles of processing of afferent information by them will be outlined; (i) afferent information of any origin is forwarded to several neuronal populations, (ii) information from any sources of input is distributed unevenly, (iii) input from several sources is integrated by individual neurons as well as by their populations, (iv) specific combinations of input are integrated by different neuronal populations and (v) afferent input to spinal interneurons is only one of the features distinguishing their functional populations. As the spinal neuronal organization and properties of neurons and afferent fibres in the so far investigated species (cat, rodents, primates) have been found to resemble, future studies utilizing molecular techniques in the mouse should allow the new data to integrate with those of the preceding studies and the principles outlined above as well as any new ones should apply also in humans.
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Affiliation(s)
- Elzbieta Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
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16
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Sumser A, Joesch M, Jonas P, Ben-Simon Y. Fast, high-throughput production of improved rabies viral vectors for specific, efficient and versatile transsynaptic retrograde labeling. eLife 2022; 11:e79848. [PMID: 36040301 PMCID: PMC9477495 DOI: 10.7554/elife.79848] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
To understand the function of neuronal circuits, it is crucial to disentangle the connectivity patterns within the network. However, most tools currently used to explore connectivity have low throughput, low selectivity, or limited accessibility. Here, we report the development of an improved packaging system for the production of the highly neurotropic RVdGenvA-CVS-N2c rabies viral vectors, yielding titers orders of magnitude higher with no background contamination, at a fraction of the production time, while preserving the efficiency of transsynaptic labeling. Along with the production pipeline, we developed suites of 'starter' AAV and bicistronic RVdG-CVS-N2c vectors, enabling retrograde labeling from a wide range of neuronal populations, tailored for diverse experimental requirements. We demonstrate the power and flexibility of the new system by uncovering hidden local and distal inhibitory connections in the mouse hippocampal formation and by imaging the functional properties of a cortical microcircuit across weeks. Our novel production pipeline provides a convenient approach to generate new rabies vectors, while our toolkit flexibly and efficiently expands the current capacity to label, manipulate and image the neuronal activity of interconnected neuronal circuits in vitro and in vivo.
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Affiliation(s)
- Anton Sumser
- Institute of Science and Technology Austria (ISTA)KlosterneuburgAustria
| | - Maximilian Joesch
- Institute of Science and Technology Austria (ISTA)KlosterneuburgAustria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA)KlosterneuburgAustria
| | - Yoav Ben-Simon
- Institute of Science and Technology Austria (ISTA)KlosterneuburgAustria
- Department of Neurophysiology and Neuropharmacology, Vienna Medical UniversityViennaAustria
- Allen Institute for Brain ScienceSeattle, WAUnited States
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17
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Gerstmann K, Jurčić N, Blasco E, Kunz S, de Almeida Sassi F, Wanaverbecq N, Zampieri N. The role of intraspinal sensory neurons in the control of quadrupedal locomotion. Curr Biol 2022; 32:2442-2453.e4. [PMID: 35512696 DOI: 10.1016/j.cub.2022.04.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 03/04/2022] [Accepted: 04/08/2022] [Indexed: 01/09/2023]
Abstract
From swimming to walking and flying, animals have evolved specific locomotor strategies to thrive in different habitats. All types of locomotion depend on the integration of motor commands and sensory information to generate precisely coordinated movements. Cerebrospinal-fluid-contacting neurons (CSF-cN) constitute a vertebrate sensory system that monitors CSF composition and flow. In fish, CSF-cN modulate swimming activity in response to changes in pH and bending of the spinal cord; however, their role in mammals remains unknown. We used mouse genetics to study their function in quadrupedal locomotion. We found that CSF-cN are directly integrated into spinal motor circuits. The perturbation of CSF-cN function does not affect general motor activity nor the generation of locomotor rhythm and pattern but results in specific defects in skilled movements. These results identify a role for mouse CSF-cN in adaptive motor control and indicate that this sensory system evolved a novel function to accommodate the biomechanical requirements of limb-based locomotion.
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Affiliation(s)
- Katrin Gerstmann
- Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Nina Jurčić
- Institut de Neurosciences de la Timone, Aix-Marseille Université (AMU) & CNRS, UMR7289, Timone Campus, 27 Boulevard Jean Moulin, 13005 Marseille, France
| | - Edith Blasco
- Institut de Neurosciences de la Timone, Aix-Marseille Université (AMU) & CNRS, UMR7289, Timone Campus, 27 Boulevard Jean Moulin, 13005 Marseille, France
| | - Severine Kunz
- Technology Platform for Electron Microscopy, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | | | - Nicolas Wanaverbecq
- Institut de Neurosciences de la Timone, Aix-Marseille Université (AMU) & CNRS, UMR7289, Timone Campus, 27 Boulevard Jean Moulin, 13005 Marseille, France
| | - Niccolò Zampieri
- Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany.
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18
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Diversified physiological sensory input connectivity questions the existence of distinct classes of spinal interneurons. iScience 2022; 25:104083. [PMID: 35372805 PMCID: PMC8971951 DOI: 10.1016/j.isci.2022.104083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 02/14/2022] [Accepted: 03/14/2022] [Indexed: 12/21/2022] Open
Abstract
The spinal cord is engaged in all forms of motor performance but its functions are far from understood. Because network connectivity defines function, we explored the connectivity of muscular, tendon, and tactile sensory inputs among a wide population of spinal interneurons in the lower cervical segments. Using low noise intracellular whole cell recordings in the decerebrated, non-anesthetized cat in vivo, we could define mono-, di-, and trisynaptic inputs as well as the weights of each input. Whereas each neuron had a highly specific input, and each indirect input could moreover be explained by inputs in other recorded neurons, we unexpectedly also found the input connectivity of the spinal interneuron population to form a continuum. Our data hence contrasts with the currently widespread notion of distinct classes of interneurons. We argue that this suggested diversified physiological connectivity, which likely requires a major component of circuitry learning, implies a more flexible functionality.
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19
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Rabies anterograde monosynaptic tracing allows identification of postsynaptic circuits receiving distinct somatosensory input. Neuroscience 2022; 491:75-86. [DOI: 10.1016/j.neuroscience.2022.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 01/13/2023]
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20
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Hongo Y, Matsui T, Nakata T, Furukawa H, Ono T, Kaida K, Suzuki K, Miyahira Y, Kobayashi Y. Morphological characterization of cholinergic partition cells: A transmitter-specific tracing study by Cre/lox-dependent viral gene expression. Ann Anat 2021; 240:151857. [PMID: 34785323 DOI: 10.1016/j.aanat.2021.151857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Partition cells are cholinergic interneurons located in lamina VII of the spinal cord. Some partition cells are the source of the cholinergic boutons, known as C-terminals or C-boutons, that modulate the activity of spinal motor neurons. Therefore, partition cells might play an important role in motor control. Previous studies categorized partition cells into three groups (medial, intermediate, and lateral partition cells) according to their distance from the central canal. However, the morphological characteristics of the three groups remain obscure. METHODS To analyze the morphology of partition cells, we developed an efficient technique for visualization of specific neurons at single-cell level in particular positions using adenovirus vectors and Cre/lox mediated recombination. Cre/lox conditional vectors were injected into the spinal cord of choline acetyltransferase-Cre transgenic mice, and partition cells labeled by green fluorescent protein were reconstructed from histological serial sections at the single-cell level. RESULTS This technique allowed for the visualization of partition cells at high resolution and revealed that partition cells had various patterns of dendrite orientations and fields. Most of the visualized partition cells had more than 60% of their dendrites located in lamina VII of the spinal cord. Partition cells had dendrites extending into various Rexed's laminae (V, VI, VII, VIII, IX, and X), but none of the cells had dendrites extending dorsal to lamina IV. The dendrites of partition cells terminated both ipsilaterally and bilaterally. We also found that C-terminals on motor neurons may be derived from the middle/outer group of partition cells. CONCLUSIONS Our results indicated that partition cells have various morphological features of the dendritic pattern and may receive differential inputs. Our results suggested that C-terminals originate not only from medial but also from intermediate/lateral cholinergic partition cells. The present study suggests that intermediate/lateral partition cells modulate activities of motor neurons through C-terminal synapses.
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Affiliation(s)
- Yu Hongo
- Department of Anatomy and Neurobiology, National Defense Medical College, Tokorozawa, Saitama, Japan; Department of Neurology, National Defense Medical College, Tokorozawa, Saitama, Japan
| | - Toshiyasu Matsui
- Department of Anatomy and Neurobiology, National Defense Medical College, Tokorozawa, Saitama, Japan; Laboratory of Veterinary Anatomy, Faculty of Veterinary Medicine, Okayama University of Science, Imabari, Ehime, Japan
| | - Takahiro Nakata
- Department of Molecular and Cellular Anatomy, Faculty of Health Promotional Sciences, Tokoha University, Shizuoka, Japan; Department of Health Science, Ishikawa Prefectural Nursing University, Ishikawa, Japan.
| | - Hiroyo Furukawa
- Department of Health Science, Ishikawa Prefectural Nursing University, Ishikawa, Japan; Department of Clinical Nutrition, Ageo Central General Hospital, Saitama, Japan
| | - Takeshi Ono
- Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan
| | - Kenichi Kaida
- Department of Neurology, National Defense Medical College, Tokorozawa, Saitama, Japan; Department of Neurology, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan
| | - Kazushi Suzuki
- Department of Neurology, National Defense Medical College, Tokorozawa, Saitama, Japan
| | - Yasushi Miyahira
- Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan
| | - Yasushi Kobayashi
- Department of Anatomy and Neurobiology, National Defense Medical College, Tokorozawa, Saitama, Japan.
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21
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Sharma P, Shah PK. In vivo electrophysiological mechanisms underlying cervical epidural stimulation in adult rats. J Physiol 2021; 599:3121-3150. [PMID: 33894695 DOI: 10.1113/jp281146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/15/2021] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS To electrophysiologically determine the predominant neural structures activated with cervical epidural stimulation (ES), well-established electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were delivered at rest, during motor activity and under anaesthesia in adult rats. Cervical ES resulted in spinal evoked motor responses with three different waveforms - early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. In contrast, MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. ERs are consequential to the direct activation of motor efferents; MRs are secondary to type-I sensory afferent activation and LRs result from the engagement of wider spinal interneuronal circuitry with potential influence from supraspinal pathways. Evidence from this work is fundamental in enhancing our understanding of cervical ES, and critical in refining the design of neuromodulation-based rehabilitative strategies and in the construction of neuroprosthetics. ABSTRACT Epidural stimulation (ES) of the lumbar spinal cord has demonstrated significant improvements in various physiological functions after a traumatic spinal cord injury in humans. Electrophysiological evidence from rodent, human and computational studies collectively suggest that the functional recovery following lumbar ES is mediated via direct activation of sensory afferent fibres. However, the mechanisms underlying cervical ES have not been comprehensively studied, which greatly limits our understanding of its effectiveness in restoring upper limb function. In this work, we determined the predominant neural structures that are activated with cervical ES using in vivo cervical spinal evoked motor responses (SEMRs). Standard electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were implemented in 11 awake and anaesthetized rats in four experimental stages. Three distinct types of cervical SEMRs were identified based on latency of their appearance: early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. Except for LRs being completely abolished under urethane, ketamine or urethane anaesthesia did not affect the appearance of cervical SEMRs. Our data, backed by literature, suggest that ERs are secondary to the direct activation of motor efferents, MRs are elicited by activation of type-I sensory afferents and LRs result from the engagement of interneuronal circuitry with potential influence from supraspinal pathways. The gathered information paves the way to designing motor rehabilitation strategies that can utilize cervical ES to recover upper limb function following neurological deficits.
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Affiliation(s)
- Pawan Sharma
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
| | - Prithvi K Shah
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
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22
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Akay T, Murray AJ. Relative Contribution of Proprioceptive and Vestibular Sensory Systems to Locomotion: Opportunities for Discovery in the Age of Molecular Science. Int J Mol Sci 2021; 22:1467. [PMID: 33540567 PMCID: PMC7867206 DOI: 10.3390/ijms22031467] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/20/2021] [Accepted: 01/26/2021] [Indexed: 12/29/2022] Open
Abstract
Locomotion is a fundamental animal behavior required for survival and has been the subject of neuroscience research for centuries. In terrestrial mammals, the rhythmic and coordinated leg movements during locomotion are controlled by a combination of interconnected neurons in the spinal cord, referred as to the central pattern generator, and sensory feedback from the segmental somatosensory system and supraspinal centers such as the vestibular system. How segmental somatosensory and the vestibular systems work in parallel to enable terrestrial mammals to locomote in a natural environment is still relatively obscure. In this review, we first briefly describe what is known about how the two sensory systems control locomotion and use this information to formulate a hypothesis that the weight of the role of segmental feedback is less important at slower speeds but increases at higher speeds, whereas the weight of the role of vestibular system has the opposite relation. The new avenues presented by the latest developments in molecular sciences using the mouse as the model system allow the direct testing of the hypothesis.
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Affiliation(s)
- Turgay Akay
- Atlantic Mobility Action Project, Brain Repair Centre, Department of Medical Neuroscience, Life Science Research Institute, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Andrew J. Murray
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, London W1T 4JG, UK
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23
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Zampieri N, de Nooij JC. Regulating muscle spindle and Golgi tendon organ proprioceptor phenotypes. CURRENT OPINION IN PHYSIOLOGY 2021; 19:204-210. [PMID: 33381667 PMCID: PMC7769215 DOI: 10.1016/j.cophys.2020.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Proprioception is an essential part of motor control. The main sensory subclasses that underlie this feedback control system - muscle spindle and Golgi tendon organ afferents - have been extensively characterized at a morphological and physiological level. More recent studies are beginning to reveal the molecular foundation for distinct proprioceptor subtypes, offering new insights into their developmental ontogeny and phenotypic diversity. This review intends to highlight some of these new findings.
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Affiliation(s)
- Niccolò Zampieri
- Max-Delbrück-Center for Molecular Medicine Berlin-Buch, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Joriene C. de Nooij
- Dept. of Neurology, Vagelos College of Physicians and Surgeons, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032.,Columbia University Motor Neuron Center, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032.,Corresponding author:
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24
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Katiyar N, Raju G, Madhusudanan P, Gopalakrishnan-Prema V, Shankarappa SA. Neuronal delivery of nanoparticles via nerve fibres in the skin. Sci Rep 2021; 11:2566. [PMID: 33510229 PMCID: PMC7844288 DOI: 10.1038/s41598-021-81995-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022] Open
Abstract
Accessing the peripheral nervous system (PNS) by topically applied nanoparticles is a simple and novel approach with clinical applications in several PNS disorders. Skin is richly innervated by long peripheral axons that arise from cell bodies located distally within ganglia. In this study we attempt to target dorsal root ganglia (DRG) neurons, via their axons by topical application of lectin-functionalized gold nanoparticles (IB4-AuNP). In vitro, 140.2 ± 1.9 nm IB4-AuNP were found to bind both axons and cell bodies of DRG neurons, and AuNP applied at the axonal terminals were found to translocate to the cell bodies. Topical application of IB4-AuNP on rat hind-paw resulted in accumulation of three to fourfold higher AuNP in lumbar DRG than in contralateral control DRGs. Results from this study clearly suggest that topically applied nanoparticles with neurotropic targeting ligands can be utilized for delivering nanoparticles to neuronal cell bodies via axonal transport mechanisms.
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Affiliation(s)
- Neeraj Katiyar
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, Kochi, 682041, Kerala, India
| | - Gayathri Raju
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, Kochi, 682041, Kerala, India
| | - Pallavi Madhusudanan
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, Kochi, 682041, Kerala, India
| | - Vignesh Gopalakrishnan-Prema
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, Kochi, 682041, Kerala, India
| | - Sahadev A Shankarappa
- Center for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Center, Amrita Vishwa Vidyapeetham University, Kochi, 682041, Kerala, India.
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25
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Ronzano R, Lancelin C, Bhumbra GS, Brownstone RM, Beato M. Proximal and distal spinal neurons innervating multiple synergist and antagonist motor pools. eLife 2021; 10:70858. [PMID: 34727018 PMCID: PMC8631798 DOI: 10.7554/elife.70858] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
Motoneurons (MNs) control muscle contractions, and their recruitment by premotor circuits is tuned to produce accurate motor behaviours. To understand how these circuits coordinate movement across and between joints, it is necessary to understand whether spinal neurons pre-synaptic to motor pools have divergent projections to more than one MN population. Here, we used modified rabies virus tracing in mice to investigate premotor interneurons projecting to synergist flexor or extensor MNs, as well as those projecting to antagonist pairs of muscles controlling the ankle joint. We show that similar proportions of premotor neurons diverge to synergist and antagonist motor pools. Divergent premotor neurons were seen throughout the spinal cord, with decreasing numbers but increasing proportion with distance from the hindlimb enlargement. In the cervical cord, divergent long descending propriospinal neurons were found in contralateral lamina VIII, had large somata, were neither glycinergic, nor cholinergic, and projected to both lumbar and cervical MNs. We conclude that distributed spinal premotor neurons coordinate activity across multiple motor pools and that there are spinal neurons mediating co-contraction of antagonist muscles.
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Affiliation(s)
- Remi Ronzano
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | - Camille Lancelin
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | - Gardave Singh Bhumbra
- Department of Neuroscience Physiology and Pharmacology, University College LondonLondonUnited Kingdom
| | - Robert M Brownstone
- Department of Neuromuscular Diseases, University College LondonLondonUnited Kingdom
| | - Marco Beato
- Neuroscience, Physiology and Pharmacology, University College LondonLondonUnited Kingdom
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26
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Systemic α-synuclein injection triggers selective neuronal pathology as seen in patients with Parkinson's disease. Mol Psychiatry 2021; 26:556-567. [PMID: 31758091 PMCID: PMC7850975 DOI: 10.1038/s41380-019-0608-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 11/07/2019] [Accepted: 11/13/2019] [Indexed: 12/25/2022]
Abstract
Parkinson's disease (PD) is an α-synucleinopathy characterized by the progressive loss of specific neuronal populations. Here, we develop a novel approach to transvascularly deliver proteins of complex quaternary structures, including α-synuclein preformed fibrils (pff). We show that a single systemic administration of α-synuclein pff triggers pathological transformation of endogenous α-synuclein in non-transgenic rats, which leads to neurodegeneration in discrete brain regions. Specifically, pff-exposed animals displayed a progressive deterioration in gastrointestinal and olfactory functions, which corresponded with the presence of cellular pathology in the central and enteric nervous systems. The α-synuclein pathology generated was both time dependent and region specific. Interestingly, the most significant neuropathological changes were observed in those brain regions affected in the early stages of PD. Our data therefore demonstrate for the first time that a single, transvascular administration of α-synuclein pff can lead to selective regional neuropathology resembling the premotor stage of idiopathic PD. Furthermore, this novel delivery approach could also be used to deliver a range of other pathogenic, as well as therapeutic, protein cargos transvascularly to the brain.
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27
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Crabé R, Aimond F, Gosset P, Scamps F, Raoul C. How Degeneration of Cells Surrounding Motoneurons Contributes to Amyotrophic Lateral Sclerosis. Cells 2020; 9:cells9122550. [PMID: 33260927 PMCID: PMC7760029 DOI: 10.3390/cells9122550] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/19/2020] [Accepted: 11/24/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by the progressive degeneration of upper and lower motoneurons. Despite motoneuron death being recognized as the cardinal event of the disease, the loss of glial cells and interneurons in the brain and spinal cord accompanies and even precedes motoneuron elimination. In this review, we provide striking evidence that the degeneration of astrocytes and oligodendrocytes, in addition to inhibitory and modulatory interneurons, disrupt the functionally coherent environment of motoneurons. We discuss the extent to which the degeneration of glial cells and interneurons also contributes to the decline of the motor system. This pathogenic cellular network therefore represents a novel strategic field of therapeutic investigation.
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Affiliation(s)
- Roxane Crabé
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Franck Aimond
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Philippe Gosset
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Frédérique Scamps
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
| | - Cédric Raoul
- The Neuroscience Institute of Montpellier, INSERM, UMR1051, University of Montpellier, 34091 Montpellier, France; (R.C.); (F.A.); (P.G.); (F.S.)
- Laboratory of Neurobiology, Kazan Federal University, 420008 Kazan, Russia
- Correspondence:
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Potratz M, Zaeck LM, Weigel C, Klein A, Freuling CM, Müller T, Finke S. Neuroglia infection by rabies virus after anterograde virus spread in peripheral neurons. Acta Neuropathol Commun 2020; 8:199. [PMID: 33228789 PMCID: PMC7684951 DOI: 10.1186/s40478-020-01074-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 11/07/2020] [Indexed: 12/17/2022] Open
Abstract
The highly neurotropic rabies virus (RABV) enters peripheral neurons at axon termini and requires long distance axonal transport and trans-synaptic spread between neurons for the infection of the central nervous system (CNS). Recent 3D imaging of field RABV-infected brains revealed a remarkably high proportion of infected astroglia, indicating that highly virulent field viruses are able to suppress astrocyte-mediated innate immune responses and virus elimination pathways. While fundamental for CNS invasion, in vivo field RABV spread and tropism in peripheral tissues is understudied. Here, we used three-dimensional light sheet and confocal laser scanning microscopy to investigate the in vivo distribution patterns of a field RABV clone in cleared high-volume tissue samples after infection via a natural (intramuscular; hind leg) and an artificial (intracranial) inoculation route. Immunostaining of virus and host markers provided a comprehensive overview of RABV infection in the CNS and peripheral nerves after centripetal and centrifugal virus spread. Importantly, we identified non-neuronal, axon-ensheathing neuroglia (Schwann cells, SCs) in peripheral nerves of the hind leg and facial regions as a target cell population of field RABV. This suggests that virus release from axons and infected SCs is part of the RABV in vivo cycle and may affect RABV-related demyelination of peripheral neurons and local innate immune responses. Detection of RABV in axon-surrounding myelinating SCs after i.c. infection further provided evidence for anterograde spread of RABV, highlighting that RABV axonal transport and spread of infectious virus in peripheral nerves is not exclusively retrograde. Our data support a new model in which, comparable to CNS neuroglia, SC infection in peripheral nerves suppresses glia-mediated innate immunity and delays antiviral host responses required for successful transport from the peripheral infection sites to the brain.
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29
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Rogers A, Beier KT. Can transsynaptic viral strategies be used to reveal functional aspects of neural circuitry? J Neurosci Methods 2020; 348:109005. [PMID: 33227339 DOI: 10.1016/j.jneumeth.2020.109005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 01/19/2023]
Abstract
Viruses have proved instrumental to elucidating neuronal connectivity relationships in a variety of organisms. Recent advances in genetic technologies have facilitated analysis of neurons directly connected to a defined starter population. These advances have also made viral transneuronal mapping available to the broader neuroscience community, where one-step rabies virus mapping has become routine. This method is commonly used to identify inputs onto defined cell populations, to demonstrate the quantitative proportion of inputs coming from specific brain regions, or to compare input patterns between two or more cell populations. Furthermore, the number of inputs labeled is often assumed to reflect the number of synaptic connections, and these viruses are commonly believed to label strong synapses more efficiently than weak synapses. While these maps are often interpreted to provide a quantitative estimate of the synaptic landscape onto starter cell populations, in fact very little is known about how transneuronal transmission takes place. We do not know how these viruses transmit between neurons, if they display biases in the cell types labeled, or even if transmission is synapse-specific. In this review, we discuss the experimental evidence against or in support of key concepts in viral tracing, focusing mostly on the use of one-step rabies input mapping and related methods. Does spread of these viruses occur specifically through synaptic connections, preferentially through synapses, or non-specifically? How efficient is viral transneuronal transmission, and is this efficiency equal in all cell types? And lastly, to what extent does viral labeling reflect functional connectivity?
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Affiliation(s)
- Alexandra Rogers
- Department of Pharmaceutical Sciences, Irvine, Irvine, CA, 92617, United States
| | - Kevin T Beier
- Department of Physiology and Biophysics, Irvine, Irvine, CA, 92617, United States; Department of Pharmaceutical Sciences, Irvine, Irvine, CA, 92617, United States; Department of Biomedical Engineering, Irvine, Irvine, CA, 92617, United States; Department of Neurobiology and Behavior, Irvine, Irvine CA, 92617, United States; Center for the Neurobiology of Learning and Memory, Irvine, Irvine, CA, 92617, United States; UCI Mind, University of California, Irvine, Irvine, CA, 92617, United States.
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30
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Henderson KW, Roche A, Menelaou E, Hale ME. Hindbrain and Spinal Cord Contributions to the Cutaneous Sensory Innervation of the Larval Zebrafish Pectoral Fin. Front Neuroanat 2020; 14:581821. [PMID: 33192344 PMCID: PMC7607007 DOI: 10.3389/fnana.2020.581821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/15/2020] [Indexed: 11/13/2022] Open
Abstract
Vertebrate forelimbs contain arrays of sensory neuron fibers that transmit signals from the skin to the nervous system. We used the genetic toolkit and optical clarity of the larval zebrafish to conduct a live imaging study of the sensory neurons innervating the pectoral fin skin. Sensory neurons in both the hindbrain and the spinal cord innervate the fin, with most cells located in the hindbrain. The hindbrain somas are located in rhombomere seven/eight, laterally and dorsally displaced from the pectoral fin motor pool. The spinal cord somas are located in the most anterior part of the cord, aligned with myomere four. Single cell reconstructions were used to map afferent processes and compare the distributions of processes to soma locations. Reconstructions indicate that this sensory system breaks from the canonical somatotopic organization of sensory systems by lacking a clear organization with reference to fin region. Arborizations from a single cell branch widely over the skin, innervating the axial skin, lateral fin surface, and medial fin surface. The extensive branching over the fin and the surrounding axial surface suggests that these fin sensory neurons report on general conditions of the fin area rather than providing fine location specificity, as has been demonstrated in other vertebrate limbs. With neuron reconstructions that span the full primary afferent arborization from the soma to the peripheral cutaneous innervation, this neuroanatomical study describes a system of primary sensory neurons and lays the groundwork for future functional studies.
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Affiliation(s)
- Katharine W Henderson
- Department of Organismal Biology and Anatomy, College of the University of Chicago, Chicago, IL, United States
| | - Alexander Roche
- Department of Organismal Biology and Anatomy, College of the University of Chicago, Chicago, IL, United States
| | - Evdokia Menelaou
- Department of Organismal Biology and Anatomy, College of the University of Chicago, Chicago, IL, United States
| | - Melina E Hale
- Department of Organismal Biology and Anatomy, College of the University of Chicago, Chicago, IL, United States
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31
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Viruses in connectomics: Viral transneuronal tracers and genetically modified recombinants as neuroscience research tools. J Neurosci Methods 2020; 346:108917. [PMID: 32835704 DOI: 10.1016/j.jneumeth.2020.108917] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/12/2020] [Accepted: 08/14/2020] [Indexed: 12/25/2022]
Abstract
Connectomic studies have become 'viral', as viral pathogens have been turned into irreplaceable neuroscience research tools. Highly sensitive viral transneuronal tracing technologies are available, based on the use of alpha-herpesviruses and a rhabdovirus (rabies virus), which function as self-amplifying markers by replicating in recipient neurons. These viruses highly differ with regard to host range, cellular receptors, peripheral uptake, replication, transport direction and specificity. Their characteristics, that make them useful for different purposes, will be highlighted and contrasted. Only transneuronal tracing with rabies virus is entirely specific. The neuroscientist toolbox currently include wild-type alpha-herpesviruses and rabies virus strains enabling polysynaptic tracing of neuronal networks across multiple synapses, as well as genetically modified viral tracers for dual transneuronal tracing, and complementary viral tools including defective and chimeric recombinants that function as single step or monosynaptically restricted tracers, or serve for monitoring and manipulating neuronal activity and gene expression. Methodological issues that are crucial for appropriate use of these technologies will be summarized. Among wild-type and genetically engineered viral tools, rabies virus and chimeric recombinants based on rabies virus as virus backbone are the most powerful, because of the ability of rabies virus to propagate exclusively among connected neurons unidirectionally (retrogradely), without affecting neuronal function. Understanding in depth viral properties is essential for neuroscientists who intend to exploit alpha-herpesviruses, rhabdoviruses or derived recombinants as research tools. Key knowledge will be summarized regarding their cellular receptors, intracellular trafficking and strategies to contrast host defense that explain their different pathophysiology and properties as research tools.
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32
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Staiger JF, Petersen CCH. Neuronal Circuits in Barrel Cortex for Whisker Sensory Perception. Physiol Rev 2020; 101:353-415. [PMID: 32816652 DOI: 10.1152/physrev.00019.2019] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The array of whiskers on the snout provides rodents with tactile sensory information relating to the size, shape and texture of objects in their immediate environment. Rodents can use their whiskers to detect stimuli, distinguish textures, locate objects and navigate. Important aspects of whisker sensation are thought to result from neuronal computations in the whisker somatosensory cortex (wS1). Each whisker is individually represented in the somatotopic map of wS1 by an anatomical unit named a 'barrel' (hence also called barrel cortex). This allows precise investigation of sensory processing in the context of a well-defined map. Here, we first review the signaling pathways from the whiskers to wS1, and then discuss current understanding of the various types of excitatory and inhibitory neurons present within wS1. Different classes of cells can be defined according to anatomical, electrophysiological and molecular features. The synaptic connectivity of neurons within local wS1 microcircuits, as well as their long-range interactions and the impact of neuromodulators, are beginning to be understood. Recent technological progress has allowed cell-type-specific connectivity to be related to cell-type-specific activity during whisker-related behaviors. An important goal for future research is to obtain a causal and mechanistic understanding of how selected aspects of tactile sensory information are processed by specific types of neurons in the synaptically connected neuronal networks of wS1 and signaled to downstream brain areas, thus contributing to sensory-guided decision-making.
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Affiliation(s)
- Jochen F Staiger
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Carl C H Petersen
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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33
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Shin MM, Catela C, Dasen J. Intrinsic control of neuronal diversity and synaptic specificity in a proprioceptive circuit. eLife 2020; 9:56374. [PMID: 32808924 PMCID: PMC7467731 DOI: 10.7554/elife.56374] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
Abstract
Relay of muscle-derived sensory information to the CNS is essential for the execution of motor behavior, but how proprioceptive sensory neurons (pSNs) establish functionally appropriate connections is poorly understood. A prevailing model of sensory-motor circuit assembly is that peripheral, target-derived, cues instruct pSN identities and patterns of intraspinal connectivity. To date no known intrinsic determinants of muscle-specific pSN fates have been described in vertebrates. We show that expression of Hox transcription factors defines pSN subtypes, and these profiles are established independently of limb muscle. The Hoxc8 gene is expressed by pSNs and motor neurons (MNs) targeting distal forelimb muscles, and sensory-specific depletion of Hoxc8 in mice disrupts sensory-motor synaptic matching, without affecting pSN survival or muscle targeting. These results indicate that the diversity and central specificity of pSNs and MNs are regulated by a common set of determinants, thus linking early rostrocaudal patterning to the assembly of limb control circuits.
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Affiliation(s)
- Maggie M Shin
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, United States
| | - Catarina Catela
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Jeremy Dasen
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, United States
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34
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Cain MD, Salimi H, Diamond MS, Klein RS. Mechanisms of Pathogen Invasion into the Central Nervous System. Neuron 2020; 103:771-783. [PMID: 31487528 DOI: 10.1016/j.neuron.2019.07.015] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/09/2019] [Accepted: 07/12/2019] [Indexed: 12/16/2022]
Abstract
CNS infections continue to rise in incidence in conjunction with increases in immunocompromised populations or conditions that contribute to the emergence of pathogens, such as global travel, climate change, and human encroachment on animal territories. The severity and complexity of these diseases is impacted by the diversity of etiologic agents and their routes of neuroinvasion. In this review, we present historical, clinical, and molecular concepts regarding the mechanisms of pathogen invasion of the CNS. We also discuss the structural components of CNS compartments that influence pathogen entry and recent discoveries of the pathways exploited by pathogens to facilitate CNS infections. Advances in our understanding of the CNS invasion mechanisms of different neurotropic pathogens may enable the development of strategies to control their entry and deliver drugs to mitigate established infections.
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Affiliation(s)
- Matthew D Cain
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hamid Salimi
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA; The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
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35
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Lavin TK, Jin L, Lea NE, Wickersham IR. Monosynaptic Tracing Success Depends Critically on Helper Virus Concentrations. Front Synaptic Neurosci 2020; 12:6. [PMID: 32116642 PMCID: PMC7033752 DOI: 10.3389/fnsyn.2020.00006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/23/2020] [Indexed: 11/13/2022] Open
Abstract
Monosynaptically-restricted transsynaptic tracing using deletion-mutant rabies virus (RV) has become a widely used technique in neuroscience, allowing identification, imaging, and manipulation of neurons directly presynaptic to a starting neuronal population. Its most common implementation is to use Cre mouse lines in combination with Cre-dependent "helper" adeno-associated viral vectors (AAVs) to supply the required genes to the targeted population before subsequent injection of a first-generation (ΔG) rabies viral vector. Here we show that the efficiency of transsynaptic spread and the degree of nonspecific labeling in wild-type control animals depend strongly on the concentrations of these helper AAVs. Our results suggest practical guidelines for achieving good results.
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Affiliation(s)
| | | | | | - Ian R. Wickersham
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States
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36
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Suzuki T, Morimoto N, Akaike A, Osakada F. Multiplex Neural Circuit Tracing With G-Deleted Rabies Viral Vectors. Front Neural Circuits 2020; 13:77. [PMID: 31998081 PMCID: PMC6967742 DOI: 10.3389/fncir.2019.00077] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/14/2019] [Indexed: 12/26/2022] Open
Abstract
Neural circuits interconnect to organize large-scale networks that generate perception, cognition, memory, and behavior. Information in the nervous system is processed both through parallel, independent circuits and through intermixing circuits. Analyzing the interaction between circuits is particularly indispensable for elucidating how the brain functions. Monosynaptic circuit tracing with glycoprotein (G) gene-deleted rabies viral vectors (RVΔG) comprises a powerful approach for studying the structure and function of neural circuits. Pseudotyping of RVΔG with the foreign envelope EnvA permits expression of transgenes such as fluorescent proteins, genetically-encoded sensors, or optogenetic tools in cells expressing TVA, a cognate receptor for EnvA. Trans-complementation with rabies virus glycoproteins (RV-G) enables trans-synaptic labeling of input neurons directly connected to the starter neurons expressing both TVA and RV-G. However, it remains challenging to simultaneously map neuronal connections from multiple cell populations and their interactions between intermixing circuits solely with the EnvA/TVA-mediated RV tracing system in a single animal. To overcome this limitation, here, we multiplexed RVΔG circuit tracing by optimizing distinct viral envelopes (oEnvX) and their corresponding receptors (oTVX). Based on the EnvB/TVB and EnvE/DR46-TVB systems derived from the avian sarcoma leukosis virus (ASLV), we developed optimized TVB receptors with lower or higher affinity (oTVB-L or oTVB-H) and the chimeric envelope oEnvB, as well as an optimized TVE receptor with higher affinity (oTVE-H) and its chimeric envelope oEnvE. We demonstrated independence of RVΔG infection between the oEnvA/oTVA, oEnvB/oTVB, and oEnvE/oTVE systems and in vivo proof-of-concept for multiplex circuit tracing from two distinct classes of layer 5 neurons targeting either other cortical or subcortical areas. We also successfully labeled common input of the lateral geniculate nucleus to both cortico-cortical layer 5 neurons and inhibitory neurons of the mouse V1 with multiplex RVΔG tracing. These oEnvA/oTVA, oEnvB/oTVB, and oEnvE/oTVE systems allow for differential labeling of distinct circuits to uncover the mechanisms underlying parallel processing through independent circuits and integrated processing through interaction between circuits in the brain.
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Affiliation(s)
- Toshiaki Suzuki
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Nao Morimoto
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan.,Laboratory of Neural Information Processing, Institute for Advanced Research, Nagoya University, Nagoya, Japan
| | - Akinori Akaike
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Fumitaka Osakada
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan.,Laboratory of Neural Information Processing, Institute for Advanced Research, Nagoya University, Nagoya, Japan.,Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, Japan.,PRESTO/CREST, Japan Science and Technology Agency, Saitama, Japan
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A customizable microfluidic platform for medium-throughput modeling of neuromuscular circuits. Biomaterials 2019; 225:119537. [PMID: 31614290 PMCID: PMC7294901 DOI: 10.1016/j.biomaterials.2019.119537] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 10/02/2019] [Accepted: 10/07/2019] [Indexed: 01/27/2023]
Abstract
Neuromuscular circuits (NMCs) are vital for voluntary movement, and effective models of NMCs are needed to understand the pathogenesis of, as well as to identify effective treatments for, multiple diseases, including Duchenne’s muscular dystrophy and amyotrophic lateral sclerosis. Microfluidics are ideal for recapitulating the central and peripheral compartments of NMCs, but myotubes often detach before functional NMCs are formed. In addition, microfluidic systems are often limited to a single experimental unit, which significantly limits their application in disease modeling and drug discovery. Here, we developed a microfluidic platform (MFP) containing over 100 experimental units, making it suitable for medium-throughput applications. To overcome detachment, we incorporated a reactive polymer surface allowing customization of the environment to culture different cell types. Using this approach, we identified conditions that enable long-term co-culture of human motor neurons and myotubes differentiated from human induced pluripotent stem cells inside our MFP. Optogenetics demonstrated the formation of functional NMCs. Furthermore, we developed a novel application of the rabies tracing assay to efficiently identify NMCs in our MFP. Therefore, our MFP enables large-scale generation and quantification of functional NMCs for disease modeling and pharmacological drug targeting.
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Beier KT. Hitchhiking on the neuronal highway: Mechanisms of transsynaptic specificity. J Chem Neuroanat 2019; 99:9-17. [PMID: 31075318 PMCID: PMC6701464 DOI: 10.1016/j.jchemneu.2019.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/20/2019] [Accepted: 05/06/2019] [Indexed: 01/28/2023]
Abstract
Transsynaptic viral tracers are an invaluable neuroanatomical tool to define neuronal circuit connectivity across single or multiple synapses. There are variants that label either inputs or outputs of defined starter populations, most of which are based on the herpes and rabies viruses. However, we still have an incomplete understanding of the factors influencing specificity of neuron-neuron transmission and labeling of inputs vs. outputs. This article will touch on three topics: First, how specific are the directional transmission patterns of these viruses? Second, what are the properties that confer synaptic specificity of viral transmission? Lastly, what can we learn from this specificity, and can we use it to devise better transsynaptic tracers?
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Affiliation(s)
- Kevin T Beier
- Department of Physiology and Biophysics, Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, 92697, United States.
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39
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Murray AJ, Croce K, Belton T, Akay T, Jessell TM. Balance Control Mediated by Vestibular Circuits Directing Limb Extension or Antagonist Muscle Co-activation. Cell Rep 2019; 22:1325-1338. [PMID: 29386118 DOI: 10.1016/j.celrep.2018.01.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 11/29/2017] [Accepted: 01/03/2018] [Indexed: 11/28/2022] Open
Abstract
Maintaining balance after an external perturbation requires modification of ongoing motor plans and the selection of contextually appropriate muscle activation patterns that respect body and limb position. We have used the vestibular system to generate sensory-evoked transitions in motor programming. In the face of a rapid balance perturbation, the lateral vestibular nucleus (LVN) generates exclusive extensor muscle activation and selective early extension of the hindlimb, followed by the co-activation of extensor and flexor muscle groups. The temporal separation in EMG response to balance perturbation reflects two distinct cell types within the LVN that generate different phases of this motor program. Initially, an LVNextensor population directs an extension movement that reflects connections with extensor, but not flexor, motor neurons. A distinct LVNco-activation population initiates muscle co-activation via the pontine reticular nucleus. Thus, distinct circuits within the LVN generate different elements of a motor program involved in the maintenance of balance.
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Affiliation(s)
- Andrew J Murray
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA; Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College London, London, UK.
| | - Katherine Croce
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Timothy Belton
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA
| | - Turgay Akay
- Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Thomas M Jessell
- Zuckerman Mind Brain Behavior Institute, Kavli Institute of Brain Science, Department of Neuroscience, Department of Biochemistry and Molecular Biophysics, and Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
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40
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Balaskas N, Abbott LF, Jessell TM, Ng D. Positional Strategies for Connection Specificity and Synaptic Organization in Spinal Sensory-Motor Circuits. Neuron 2019; 102:1143-1156.e4. [PMID: 31076274 DOI: 10.1016/j.neuron.2019.04.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/04/2019] [Accepted: 03/29/2019] [Indexed: 11/17/2022]
Abstract
Proprioceptive sensory axons in the spinal cord form selective connections with motor neuron partners, but the strategies that confer such selectivity remain uncertain. We show that muscle-specific sensory axons project to motor neurons along topographically organized angular trajectories and that motor pools exhibit diverse dendritic arbors. On the basis of spatial constraints on axo-dendritic interactions, we propose positional strategies that can account for sensory-motor connectivity and synaptic organization. These strategies rely on two patterning principles. First, the degree of axo-dendritic overlap reduces the number of potential post-synaptic partners. Second, a close correlation between the small angle of axo-dendritic approach and the formation of synaptic clusters imposes specificity of connections when sensory axons intersect multiple motor pools with overlapping dendritic arbors. Our study identifies positional strategies with prominent roles in the organization of spinal sensory-motor circuits.
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Affiliation(s)
- Nikolaos Balaskas
- The Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
| | - L F Abbott
- The Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Thomas M Jessell
- Departments of Neuroscience, and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - David Ng
- The Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
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41
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Mahadi KM, Lall VK, Deuchars SA, Deuchars J. Cardiovascular autonomic effects of transcutaneous auricular nerve stimulation via the tragus in the rat involve spinal cervical sensory afferent pathways. Brain Stimul 2019; 12:1151-1158. [PMID: 31129152 DOI: 10.1016/j.brs.2019.05.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 04/17/2019] [Accepted: 05/02/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Electrical stimulation on select areas of the external auricular dermatome influences the autonomic nervous system. It has been postulated that activation of the Auricular Branch of the Vagus Nerve (ABVN) mediates such autonomic changes. However, the underlying neural pathways mediating these effects are unknown and, further, our understanding of the anatomical distribution of the ABVN in the auricle has now been questioned. OBJECTIVE To investigate the effects of electrical stimulation of the tragus on autonomic outputs in the rat and probe the underlying neural pathways. METHODS Central neuronal projections from nerves innervating the external auricle were investigated by injections of the transganglionic tracer cholera toxin B chain (CTB) into the right tragus of Wistar rats. Physiological recordings of heart rate, perfusion pressure, respiratory rate and sympathetic nerve activity were made in an anaesthetic free Working Heart Brainstem Preparation (WHBP) of the rat and changes in response to electrical stimulation of the tragus analysed. RESULTS Neuronal tracing from the tragus revealed that the densest CTB labelling was within laminae III-IV of the dorsal horn of the upper cervical spinal cord, ipsilateral to the injection sites. In the medulla oblongata, CTB labelled afferents were observed in the paratrigeminal nucleus, spinal trigeminal tract and cuneate nucleus. Surprisingly, only sparse labelling was observed in the vagal afferent termination site, the nucleus tractus solitarius. Recordings made from rats at night time revealed more robust sympathetic activity in comparison to day time rats, thus subsequent experiments were conducted in rats at night time. Electrical stimulation was delivered across the tragus for 5 min. Direct recording from the sympathetic chain revealed a central sympathoinhibition by up to 36% following tragus stimulation. Sympathoinhibition remained following sectioning of the cervical vagus nerve ipsilateral to the stimulation site, but was attenuated by sectioning of the upper cervical afferent nerve roots. CONCLUSIONS Inhibition of the sympathetic nervous system activity upon electrical stimulation of the tragus in the rat is mediated at least in part through sensory afferent projections to the upper cervical spinal cord. This challenges the notion that tragal stimulation is mediated by the auricular branch of the vagus nerve and suggests that alternative mechanisms may be involved.
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Affiliation(s)
- K M Mahadi
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, United Kingdom; Drug and Herbal Research Centre, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - V K Lall
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, United Kingdom
| | - S A Deuchars
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, United Kingdom.
| | - J Deuchars
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, United Kingdom.
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42
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Guo Y, Duan M, Wang X, Gao J, Guan Z, Zhang M. Early events in rabies virus infection—Attachment, entry, and intracellular trafficking. Virus Res 2019; 263:217-225. [DOI: 10.1016/j.virusres.2019.02.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/28/2019] [Accepted: 02/13/2019] [Indexed: 12/20/2022]
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43
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Henderson KW, Menelaou E, Hale ME. Sensory neurons in the spinal cord of zebrafish and their local connectivity. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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44
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Bokiniec P, Zampieri N, Lewin GR, Poulet JF. The neural circuits of thermal perception. Curr Opin Neurobiol 2018; 52:98-106. [PMID: 29734030 PMCID: PMC6191924 DOI: 10.1016/j.conb.2018.04.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/13/2018] [Accepted: 04/07/2018] [Indexed: 01/01/2023]
Abstract
Thermal information about skin surface temperature is a key sense for the perception of object identity and valence. The identification of ion channels involved in the transduction of thermal changes has provided a genetic access point to the thermal system. However, from sensory specific 'labeled-lines' to multimodal interactive pathways, the functional organization and identity of the neural circuits mediating innocuous thermal perception have been debated for over 100 years. Here we highlight points in the system that require further attention and review recent advances using in vivo electrophysiology, cellular resolution calcium imaging, optogenetics and thermal perceptual tasks in behaving mice that have begun to uncover the anatomical principles and neural processing mechanisms underlying innocuous thermal perception.
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Affiliation(s)
- Phillip Bokiniec
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Germany; Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin, Berlin, Germany
| | - Niccolò Zampieri
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Germany; Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin, Berlin, Germany
| | - Gary R Lewin
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Germany; Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin, Berlin, Germany
| | - James Fa Poulet
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Germany; Neuroscience Research Center and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin, Berlin, Germany.
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Neuroanatomical evidence of the transport of the rabies virus through the propriospinal tract in the spinal cord of mice. BIOMEDICA 2018; 38:209-215. [PMID: 30184349 DOI: 10.7705/biomedica.v38i0.3711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 08/03/2017] [Indexed: 11/21/2022]
Abstract
Introduction: Information about the neuroanatomical details of the ascendant transport of the rabies virus through the spinal cord is scarce.
Objective: To identify the neuroanatomical route of dissemination of the rabies virus at each of the levels of the spinal cord of mice after being inoculated intramuscularly.
Materials and methods: Mice were inoculated with the rabies virus in the hamstrings. After 24 hours post-inoculation, every eight hours, five animals were sacrificed by perfusion with paraformaldehyde. Then, the spinal cord was removed, and transverse cuts were made at the lumbosacral, thoracic, and cervical levels. These were processed by immunohistochemistry for the detection of viral antigens.
Results: The first antigens of rabies were observed as aggregated particles in the lumbar spinal cord at 24 hours post-inoculation, within the ventral horn in the same side of the inoculated limb. At 32 hours post inoculation the first motoneurons immunoreactive to the virus became visible. At 40 hours postinoculation the first immunoreactive neurons were revealed in the thoracic level, located on lamina 8 and at 48 hours post-inoculation in the cervical cord, also on lamina 8. At 56 hours post-inoculation the virus had spread throughout the spinal cord, but the animals still did not show signs of the disease.
Conclusion: In the mouse model we used, the rabies virus entered the spinal cord through the motoneurons and probably used the descending propriospinal pathway for its retrograde axonal transport to the encephalus.
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46
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Overexpression of MAP2 and NF-H Associated with Dendritic Pathology in the Spinal Cord of Mice Infected with Rabies Virus. Viruses 2018; 10:v10030112. [PMID: 29509660 PMCID: PMC5869505 DOI: 10.3390/v10030112] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 12/13/2022] Open
Abstract
Rabies is a viral infection that targets the nervous system, specifically neurons. The clinical manifestations of the disease are dramatic and their outcome fatal; paradoxically, conventional histopathological descriptions reveal only subtle changes in the affected nervous tissue. Some researchers have considered that the pathophysiology of rabies is based more on biochemical changes than on structural alterations, as is the case with some psychiatric diseases. However, we believe that it has been necessary to resort to other methods that allow us to analyze the effect of the infection on neurons. The Golgi technique is the gold standard for studying the morphology of all the components of a neuron and the cytoskeletal proteins are the structural support of dendrites and axons. We have previously shown, in the mouse cerebral cortex and now with this work in spinal cord, that rabies virus generates remarkable alterations in the morphological pattern of the neurons and that this effect is associated with the increase in the expression of two cytoskeletal proteins (MAP2 and NF-H). It is necessary to deepen the investigation of the pathogenesis of rabies in order to find therapeutic alternatives to a disease to which the World Health Organization classifies as a neglected disease.
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47
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Imai F, Yoshida Y. Molecular mechanisms underlying monosynaptic sensory-motor circuit development in the spinal cord. Dev Dyn 2018; 247:581-587. [PMID: 29226492 DOI: 10.1002/dvdy.24611] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 12/07/2017] [Accepted: 12/07/2017] [Indexed: 02/06/2023] Open
Abstract
Motor behaviors are precisely controlled by the integration of sensory and motor systems in the central nervous system (CNS). Proprioceptive sensory neurons, key components of the sensory system, are located in the dorsal root ganglia and project axons both centrally to the spinal cord and peripherally to muscles and tendons, communicating peripheral information about the body to the CNS. Changes in muscle length detected by muscle spindles, and tension variations in tendons conveyed by Golgi tendon organs, are communicated to the CNS through group Ia /II, and Ib proprioceptive sensory afferents, respectively. Group Ib proprioceptive sensory neurons connect with motor neurons indirectly through spinal interneurons, whereas group Ia/II axons form both direct (monosynaptic) and indirect connections with motor neurons. Although monosynaptic sensory-motor circuits between spindle proprioceptive sensory neurons and motor neurons have been extensively studied since 1950s, the molecular mechanisms underlying their formation and upkeep have only recently begun to be understood. We will discuss our current understanding of the molecular foundation of monosynaptic circuit development and maintenance involving proprioceptive sensory neurons and motor neurons in the mammalian spinal cord. Developmental Dynamics 247:581-587, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Fumiyasu Imai
- Divisions of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Yutaka Yoshida
- Divisions of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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48
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Boosting of Thalamic D2 Dopaminergic Transmission: A Potential Strategy for Drug-Seeking Attenuation. eNeuro 2017; 4:eN-COM-0378-17. [PMID: 29279859 PMCID: PMC5738865 DOI: 10.1523/eneuro.0378-17.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 11/27/2017] [Accepted: 11/30/2017] [Indexed: 01/30/2023] Open
Abstract
This commentary focuses on novel findings by Clark et al. (2017) published in eNeuro, which show that dopamine D2 receptors (D2Rs) in the paraventricular nucleus of the thalamus (PVT) are involved in cocaine sensitization. We extend the discussion on how their findings contribute to our understanding of the role of the PVT in drug seeking by providing new insight on the role of the PVT in the regulation of food-seeking and fear responses. We also consider the significance of the neuroanatomical findings reported by Clark et al., that the PVT is reciprocally connected with areas of the brain involved in addiction and discuss the implications associated with the source and type of dopaminergic fibers innervating this area of the thalamus.
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49
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Fooks AR, Cliquet F, Finke S, Freuling C, Hemachudha T, Mani RS, Müller T, Nadin-Davis S, Picard-Meyer E, Wilde H, Banyard AC. Rabies. Nat Rev Dis Primers 2017; 3:17091. [PMID: 29188797 DOI: 10.1038/nrdp.2017.91] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Rabies is a life-threatening neglected tropical disease: tens of thousands of cases are reported annually in endemic countries (mainly in Africa and Asia), although the actual numbers are most likely underestimated. Rabies is a zoonotic disease that is caused by infection with viruses of the Lyssavirus genus, which are transmitted via the saliva of an infected animal. Dogs are the most important reservoir for rabies viruses, and dog bites account for >99% of human cases. The virus first infects peripheral motor neurons, and symptoms occur after the virus reaches the central nervous system. Once clinical disease develops, it is almost certainly fatal. Primary prevention involves dog vaccination campaigns to reduce the virus reservoir. If exposure occurs, timely post-exposure prophylaxis can prevent the progression to clinical disease and involves appropriate wound care, the administration of rabies immunoglobulin and vaccination. A multifaceted approach for human rabies eradication that involves government support, disease awareness, vaccination of at-risk human populations and, most importantly, dog rabies control is necessary to achieve the WHO goal of reducing the number of cases of dog-mediated human rabies to zero by 2030.
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Affiliation(s)
- Anthony R Fooks
- Animal and Plant Health Agency (APHA), Wildlife Zoonoses and Vector Borne Diseases Research Group, (WHO Collaborating Centre for the Characterisation of Rabies and Rabies-Related Viruses, World Organisation for Animal Health (OIE) Reference Laboratory for Rabies), Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.,Institute of Infection &Global Health, University of Liverpool, Liverpool, UK.,Institute for Infection and Immunity, St. George's Hospital Medical School, University of London, London, UK
| | - Florence Cliquet
- French Agency for Food, Environmental and Occupational Health &Safety (ANSES)-Nancy Laboratory for Rabies and Wildlife (European Union Reference Laboratory for Rabies, WHO Collaborating Centre for Research and Management in Zoonoses Control, OIE Reference Laboratory for Rabies, European Union Reference Institute for Rabies Serology), Technopôle Agricole et Vétérinaire de Pixérécourt, Malzéville, France
| | - Stefan Finke
- Institute of Molecular Virology and Cell Biology (WHO Collaborating Centre for Rabies Surveillance and Research, OIE Reference Laboratory for Rabies), Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Conrad Freuling
- Institute of Molecular Virology and Cell Biology (WHO Collaborating Centre for Rabies Surveillance and Research, OIE Reference Laboratory for Rabies), Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Thiravat Hemachudha
- Department of Medicine (Neurology) and (WHO Collaborating Centre for Research and Training on Viral Zoonoses), Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Thai Red Cross Emerging Infectious Disease-Health Science Centre, Thai Red Cross Society, Bangkok, Thailand
| | - Reeta S Mani
- Department of Neurovirology (WHO Collaborating Centre for Reference and Research in Rabies), National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Thomas Müller
- Institute of Molecular Virology and Cell Biology (WHO Collaborating Centre for Rabies Surveillance and Research, OIE Reference Laboratory for Rabies), Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Susan Nadin-Davis
- Ottawa Laboratory Fallowfield, Canadian Food Inspection Agency (WHO Collaborating Centre for Control, Pathogenesis and Epidemiology of Rabies in Carnivores), Ottawa, Ontario, Canada
| | - Evelyne Picard-Meyer
- French Agency for Food, Environmental and Occupational Health &Safety (ANSES)-Nancy Laboratory for Rabies and Wildlife (European Union Reference Laboratory for Rabies, WHO Collaborating Centre for Research and Management in Zoonoses Control, OIE Reference Laboratory for Rabies, European Union Reference Institute for Rabies Serology), Technopôle Agricole et Vétérinaire de Pixérécourt, Malzéville, France
| | - Henry Wilde
- Department of Medicine (Neurology) and (WHO Collaborating Centre for Research and Training on Viral Zoonoses), Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Ashley C Banyard
- Animal and Plant Health Agency (APHA), Wildlife Zoonoses and Vector Borne Diseases Research Group, (WHO Collaborating Centre for the Characterisation of Rabies and Rabies-Related Viruses, World Organisation for Animal Health (OIE) Reference Laboratory for Rabies), Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK
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50
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Lin SD, Tang T, Zhao TB, Liu SJ. Central projections and connections of lumbar primary afferent fibers in adult rats: effectively revealed using Texas red-dextran amine tracing. Neural Regen Res 2017; 12:1695-1702. [PMID: 29171435 PMCID: PMC5696851 DOI: 10.4103/1673-5374.217371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Signals from lumbar primary afferent fibers are important for modulating locomotion of the hind-limbs. However, silver impregnation techniques, autoradiography, wheat germ agglutinin-horseradish peroxidase and cholera toxin B subunit-horseradish peroxidase cannot image the central projections and connections of the dorsal root in detail. Thus, we injected 3-kDa Texas red-dextran amine into the proximal trunks of L4 dorsal roots in adult rats. Confocal microscopy results revealed that numerous labeled arborizations and varicosities extended to the dorsal horn from T12–S4, to Clarke's column from T10–L2, and to the ventral horn from L1–5. The labeled varicosities at the L4 cord level were very dense, particularly in laminae I–III, and the density decreased gradually in more rostral and caudal segments. In addition, they were predominately distributed in laminae I–IV, moderately in laminae V–VII and sparsely in laminae VIII–X. Furthermore, direct contacts of lumbar afferent fibers with propriospinal neurons were widespread in gray matter. In conclusion, the projection and connection patterns of L4 afferents were illustrated in detail by Texas red-dextran amine-dorsal root tracing.
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Affiliation(s)
- Shi-de Lin
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing; Department of Spinal Cord Injury, the General Hospital of Jinan Military Command, Jinan, Shandong Province, China
| | - Tao Tang
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Ting-Bao Zhao
- Department of Spinal Cord Injury, the General Hospital of Jinan Military Command, Jinan, Shandong Province, China
| | - Shao-Jun Liu
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
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