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Espino CM, Nagaraja C, Ortiz S, Dayton JR, Murali AR, Ma Y, Mann EL, Garlapalli S, Wohlgemuth RP, Brashear SE, Smith LR, Wilkinson KA, Griffith TN. Differential encoding of mammalian proprioception by voltage-gated sodium channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609982. [PMID: 39253497 PMCID: PMC11383322 DOI: 10.1101/2024.08.27.609982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
Animals that require purposeful movement for survival are endowed with mechanosensory neurons called proprioceptors that provide essential sensory feedback from muscles and joints to spinal cord circuits, which modulates motor output. Despite the essential nature of proprioceptive signaling in daily life, the mechanisms governing proprioceptor activity are poorly understood. Here, we have identified distinct and nonredundant roles for two voltage-gated sodium channels (NaVs), NaV1.1 and NaV1.6, in mammalian proprioception. Deletion of NaV1.6 in somatosensory neurons (NaV1.6cKO mice) causes severe motor deficits accompanied by complete loss of proprioceptive transmission, which contrasts with our previous findings using similar mouse models to target NaV1.1 (NaV1.1cKO). In NaV1.6cKO animals, loss of proprioceptive feedback caused non-cell-autonomous impairments in proprioceptor end-organs and skeletal muscle that were absent in NaV1.1cKO mice. We attribute the differential contribution of NaV1.1 and NaV1.6 in proprioceptor function to distinct cellular localization patterns. Collectively, these data provide the first evidence that NaV subtypes uniquely shape neurotransmission within a somatosensory modality.
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Affiliation(s)
- Cyrrus M Espino
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
| | - Chetan Nagaraja
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
| | - Serena Ortiz
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Jacquelyn R Dayton
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
| | - Akash R Murali
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
- Undergraduate Program in Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Yanki Ma
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
- Undergraduate Program in Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA, USA
| | - Emari L Mann
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
- Postbaccalaureate Research Education Program at UC Davis, University of California, Davis, Davis, CA, USA
| | - Snigdha Garlapalli
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
- Undergraduate Program in Psychology, University of California, Davis, Davis, CA, USA
| | - Ross P Wohlgemuth
- Department of Physiology, Neurobiology, and Behavior, University of California, Davis, Davis, CA, USA
| | - Sarah E Brashear
- Department of Physiology, Neurobiology, and Behavior, University of California, Davis, Davis, CA, USA
| | - Lucas R Smith
- Department of Physiology, Neurobiology, and Behavior, University of California, Davis, Davis, CA, USA
| | | | - Theanne N Griffith
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, USA
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Lee SYJ, Dallmann CJ, Cook AP, Tuthill JC, Agrawal S. Divergent neural circuits for proprioceptive and exteroceptive sensing of the Drosophila leg. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.23.590808. [PMID: 38712128 PMCID: PMC11071415 DOI: 10.1101/2024.04.23.590808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Somatosensory neurons provide the nervous system with information about mechanical forces originating inside and outside the body. Here, we use connectomics to reconstruct and analyze neural circuits downstream of the largest somatosensory organ in the Drosophila leg, the femoral chordotonal organ (FeCO). The FeCO has been proposed to support both proprioceptive sensing of the fly's femur-tibia joint and exteroceptive sensing of substrate vibrations, but it remains unknown which sensory neurons and central circuits contribute to each of these functions. We found that different subtypes of FeCO sensory neurons feed into distinct proprioceptive and exteroceptive pathways. Position- and movement-encoding FeCO neurons connect to local leg motor control circuits in the ventral nerve cord (VNC), indicating a proprioceptive function. In contrast, signals from the vibration-encoding FeCO neurons are integrated across legs and transmitted to auditory regions in the brain, indicating an exteroceptive function. Overall, our analyses reveal the structure of specialized circuits for processing proprioceptive and exteroceptive signals from the fly leg. They also demonstrate how analyzing patterns of synaptic connectivity can distill organizing principles from complex sensorimotor circuits.
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3
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Carmona LM, Thomas ED, Smith K, Tasic B, Costa RM, Nelson A. Topographical and cell type-specific connectivity of rostral and caudal forelimb corticospinal neuron populations. Cell Rep 2024; 43:113993. [PMID: 38551963 PMCID: PMC11100358 DOI: 10.1016/j.celrep.2024.113993] [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: 12/01/2023] [Revised: 02/07/2024] [Accepted: 03/07/2024] [Indexed: 04/09/2024] Open
Abstract
Corticospinal neurons (CSNs) synapse directly on spinal neurons, a diverse assortment of cells with unique structural and functional properties necessary for body movements. CSNs modulating forelimb behavior fractionate into caudal forelimb area (CFA) and rostral forelimb area (RFA) motor cortical populations. Despite their prominence, the full diversity of spinal neurons targeted by CFA and RFA CSNs is uncharted. Here, we use anatomical and RNA sequencing methods to show that CSNs synapse onto a remarkably selective group of spinal cell types, favoring inhibitory populations that regulate motoneuron activity and gate sensory feedback. CFA and RFA CSNs target similar spinal neuron types, with notable exceptions that suggest that these populations differ in how they influence behavior. Finally, axon collaterals of CFA and RFA CSNs target similar brain regions yet receive highly divergent inputs. These results detail the rules of CSN connectivity throughout the brain and spinal cord for two regions critical for forelimb behavior.
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Affiliation(s)
- Lina Marcela Carmona
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Eric D Thomas
- Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Kimberly Smith
- Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Bosiljka Tasic
- Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Rui M Costa
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Allen Institute for Brain Science, Allen Institute, Seattle, WA, USA
| | - Anders Nelson
- Center for Neural Science, New York University, New York, NY 10003, USA.
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4
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Gradwell MA, Ozeri-Engelhard N, Eisdorfer JT, Laflamme OD, Gonzalez M, Upadhyay A, Medlock L, Shrier T, Patel KR, Aoki A, Gandhi M, Abbas-Zadeh G, Oputa O, Thackray JK, Ricci M, George A, Yusuf N, Keating J, Imtiaz Z, Alomary SA, Bohic M, Haas M, Hernandez Y, Prescott SA, Akay T, Abraira VE. Multimodal sensory control of motor performance by glycinergic interneurons of the mouse spinal cord deep dorsal horn. Neuron 2024; 112:1302-1327.e13. [PMID: 38452762 DOI: 10.1016/j.neuron.2024.01.027] [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: 06/13/2023] [Revised: 10/31/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024]
Abstract
Sensory feedback is integral for contextually appropriate motor output, yet the neural circuits responsible remain elusive. Here, we pinpoint the medial deep dorsal horn of the mouse spinal cord as a convergence point for proprioceptive and cutaneous input. Within this region, we identify a population of tonically active glycinergic inhibitory neurons expressing parvalbumin. Using anatomy and electrophysiology, we demonstrate that deep dorsal horn parvalbumin-expressing interneuron (dPV) activity is shaped by convergent proprioceptive, cutaneous, and descending input. Selectively targeting spinal dPVs, we reveal their widespread ipsilateral inhibition onto pre-motor and motor networks and demonstrate their role in gating sensory-evoked muscle activity using electromyography (EMG) recordings. dPV ablation altered limb kinematics and step-cycle timing during treadmill locomotion and reduced the transitions between sub-movements during spontaneous behavior. These findings reveal a circuit basis by which sensory convergence onto dorsal horn inhibitory neurons modulates motor output to facilitate smooth movement and context-appropriate transitions.
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Affiliation(s)
- Mark A Gradwell
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Nofar Ozeri-Engelhard
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Neuroscience PhD program, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Jaclyn T Eisdorfer
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Olivier D Laflamme
- Dalhousie PhD program, Dalhousie University, Halifax, NS, Canada; Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, NS, Canada
| | - Melissa Gonzalez
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Biomedical Engineering, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Aman Upadhyay
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Neuroscience PhD program, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Laura Medlock
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Tara Shrier
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Komal R Patel
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Adin Aoki
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Melissa Gandhi
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Gloria Abbas-Zadeh
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Olisemaka Oputa
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Joshua K Thackray
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Human Genetics Institute of New Jersey, Rutgers University, The State University of New Jersey, Piscataway, NJ, USA; Tourette International Collaborative Genetics Study (TIC Genetics)
| | - Matthew Ricci
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Arlene George
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Nusrath Yusuf
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Neuroscience PhD program, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Jessica Keating
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Zarghona Imtiaz
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Simona A Alomary
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Manon Bohic
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Michael Haas
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Yurdiana Hernandez
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Steven A Prescott
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Turgay Akay
- Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, NS, Canada
| | - Victoria E Abraira
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA.
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Tasnim A, Alkislar I, Hakim R, Turecek J, Abdelaziz A, Orefice LL, Ginty DD. The developmental timing of spinal touch processing alterations predicts behavioral changes in genetic mouse models of autism spectrum disorders. Nat Neurosci 2024; 27:484-496. [PMID: 38233682 PMCID: PMC10917678 DOI: 10.1038/s41593-023-01552-9] [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: 05/04/2023] [Accepted: 12/12/2023] [Indexed: 01/19/2024]
Abstract
Altered somatosensory reactivity is frequently observed among individuals with autism spectrum disorders (ASDs). Here, we report that although multiple mouse models of ASD exhibit aberrant somatosensory behaviors in adulthood, some models exhibit altered tactile reactivity as early as embryonic development, whereas in others, altered reactivity emerges later in life. Additionally, tactile overreactivity during neonatal development is associated with anxiety-like behaviors and social behavior deficits in adulthood, whereas tactile overreactivity that emerges later in life is not. The locus of circuit disruption dictates the timing of aberrant tactile behaviors, as altered feedback or presynaptic inhibition of peripheral mechanosensory neurons leads to abnormal tactile reactivity during neonatal development, whereas disruptions in feedforward inhibition in the spinal cord lead to touch reactivity alterations that manifest later in life. Thus, the developmental timing of aberrant touch processing can predict the manifestation of ASD-associated behaviors in mouse models, and differential timing of sensory disturbance onset may contribute to phenotypic diversity across individuals with ASD.
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Affiliation(s)
- Aniqa Tasnim
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Ilayda Alkislar
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Richard Hakim
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Josef Turecek
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Amira Abdelaziz
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Lauren L Orefice
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
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6
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Rankin G, Chirila AM, Emanuel AJ, Zhang Z, Woolf CJ, Drugowitsch J, Ginty DD. Nerve injury disrupts temporal processing in the spinal cord dorsal horn through alterations in PV + interneurons. Cell Rep 2024; 43:113718. [PMID: 38294904 PMCID: PMC11101906 DOI: 10.1016/j.celrep.2024.113718] [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: 03/15/2023] [Revised: 11/13/2023] [Accepted: 01/11/2024] [Indexed: 02/02/2024] Open
Abstract
How mechanical allodynia following nerve injury is encoded in patterns of neural activity in the spinal cord dorsal horn (DH) remains incompletely understood. We address this in mice using the spared nerve injury model of neuropathic pain and in vivo electrophysiological recordings. Surprisingly, despite dramatic behavioral over-reactivity to mechanical stimuli following nerve injury, an overall increase in sensitivity or reactivity of DH neurons is not observed. We do, however, observe a marked decrease in correlated neural firing patterns, including the synchrony of mechanical stimulus-evoked firing, across the DH. Alterations in DH temporal firing patterns are recapitulated by silencing DH parvalbumin+ (PV+) interneurons, previously implicated in mechanical allodynia, as are allodynic pain-like behaviors. These findings reveal decorrelated DH network activity, driven by alterations in PV+ interneurons, as a prominent feature of neuropathic pain and suggest restoration of proper temporal activity as a potential therapeutic strategy to treat chronic neuropathic pain.
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Affiliation(s)
- Genelle Rankin
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Anda M Chirila
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Alan J Emanuel
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Zihe Zhang
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Clifford J Woolf
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Jan Drugowitsch
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - David D Ginty
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
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de Nooij JC, Zampieri N. The making of a proprioceptor: a tale of two identities. Trends Neurosci 2023; 46:1083-1094. [PMID: 37858440 DOI: 10.1016/j.tins.2023.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/21/2023]
Abstract
Proprioception, the sense of body position in space, has a critical role in the control of posture and movement. Aside from skin and joint receptors, the main sources of proprioceptive information in tetrapods are mechanoreceptive end organs in skeletal muscle: muscle spindles (MSs) and Golgi tendon organs (GTOs). The sensory neurons that innervate these receptors are divided into subtypes that detect discrete aspects of sensory information from muscles with different biomechanical functions. Despite the importance of proprioceptive neurons in motor control, the developmental mechanisms that control the acquisition of their distinct functional properties and positional identity are not yet clear. In this review, we discuss recent findings on the development of mouse proprioceptor subtypes and challenges in defining them at the molecular and functional level.
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Affiliation(s)
- Joriene C de Nooij
- Department of Neurology, Division of Translational Neurobiology, Vagelos College of Physicians and Surgeons, 650 West 168th Street, New York, NY 10032, USA; Columbia University Motor Neuron Center, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA.
| | - Niccolò Zampieri
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany.
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8
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Carmona LM, Thomas ET, Smith K, Tasic B, Costa RM, Nelson A. Topographical and cell type-specific connectivity of rostral and caudal forelimb corticospinal neuron populations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567623. [PMID: 38014164 PMCID: PMC10680840 DOI: 10.1101/2023.11.17.567623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Corticospinal neurons (CSNs) synapse directly on spinal neurons, a diverse group of neurons with unique structural and functional properties necessary for body movements. CSNs modulating forelimb behavior fractionate into caudal forelimb area (CFA) and rostral forelimb area (RFA) motor cortical populations. Despite their prominence, no studies have mapped the diversity of spinal cell types targeted by CSNs, let alone compare CFA and RFA populations. Here we use anatomical and RNA-sequencing methods to show that CSNs synapse onto a remarkably selective group of spinal cell types, favoring inhibitory populations that regulate motoneuron activity and gate sensory feedback. CFA and RFA CSNs target similar spinal cell types, with notable exceptions that suggest these populations differ in how they influence behavior. Finally, axon collaterals of CFA and RFA CSNs target similar brain regions yet receive surprisingly divergent inputs. These results detail the rules of CSN connectivity throughout the brain and spinal cord for two regions critical for forelimb behavior.
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9
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Zheng X, Liu Z, He Z, Xu J, Wang Y, Gong C, Zhang R, Zhang SC, Chen H, Wang W. Preclinical long-term safety of intraspinal transplantation of human dorsal spinal GABA neural progenitor cells. iScience 2023; 26:108306. [PMID: 38026209 PMCID: PMC10661464 DOI: 10.1016/j.isci.2023.108306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/28/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Human pluripotent stem cell (hPSC)-derived neurons have shown promise in treating spinal cord injury (SCI). We previously showed that hPSC-derived dorsal spinal γ-aminobutyric acid (GABA) neurons can alleviate spasticity and promote locomotion in rats with SCI, but their long-term safety remains elusive. Here, we characterized the long-term fate and safety of human dorsal spinal GABA neural progenitor cells (NPCs) in naive rats over one year. All grafted NPCs had undergone differentiation, yielding mainly neurons and astrocytes. Fully mature human neurons grew many axons and formed numerous synapses with rat neural circuits, together with mature human astrocytes that structurally integrated into the rat spinal cord. The sensorimotor function of rats was not impaired by intraspinal transplantation, even when human neurons were activated or inhibited by designer receptors exclusively activated by designer drugs (DREADDs). These findings represent a significant step toward the clinical translation of human spinal neuron transplantation for treating SCI.
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Affiliation(s)
- Xiaolong Zheng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhixian Liu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ziyu He
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jia Xu
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- Stem Cell Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - YaNan Wang
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - ChenZi Gong
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ruoying Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Su-Chun Zhang
- Waisman Center, Department of Neuroscience and Department of Neurology, University of Wisconsin, Madison, WI, USA
- Program in Neuroscience & Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- Stem Cell Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- Hubei Key Laboratory of Neural Injury and Functional Reconstruction, Huazhong University of Science and Technology, Wuhan 430030, China
- Key Laboratory of Neurological Diseases of Chinese Ministry of Education, the School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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10
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Kuehn N, Schwarz A, Beretta CA, Schwarte Y, Schmitt F, Motsch M, Weidner N, Puttagunta R. Intermediate gray matter interneurons in the lumbar spinal cord play a critical and necessary role in coordinated locomotion. PLoS One 2023; 18:e0291740. [PMID: 37906544 PMCID: PMC10617729 DOI: 10.1371/journal.pone.0291740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 09/05/2023] [Indexed: 11/02/2023] Open
Abstract
Locomotion is a complex task involving excitatory and inhibitory circuitry in spinal gray matter. While genetic knockouts examine the function of individual spinal interneuron (SpIN) subtypes, the phenotype of combined SpIN loss remains to be explored. We modified a kainic acid lesion to damage intermediate gray matter (laminae V-VIII) in the lumbar spinal enlargement (spinal L2-L4) in female rats. A thorough, tailored behavioral evaluation revealed deficits in gross hindlimb function, skilled walking, coordination, balance and gait two weeks post-injury. Using a Random Forest algorithm, we combined these behavioral assessments into a highly predictive binary classification system that strongly correlated with structural deficits in the rostro-caudal axis. Machine-learning quantification confirmed interneuronal damage to laminae V-VIII in spinal L2-L4 correlates with hindlimb dysfunction. White matter alterations and lower motoneuron loss were not observed with this KA lesion. Animals did not regain lost sensorimotor function three months after injury, indicating that natural recovery mechanisms of the spinal cord cannot compensate for loss of laminae V-VIII neurons. As gray matter damage accounts for neurological/walking dysfunction in instances of spinal cord injury affecting the cervical or lumbar enlargement, this research lays the groundwork for new neuroregenerative therapies to replace these lost neuronal pools vital to sensorimotor function.
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Affiliation(s)
- Naëmi Kuehn
- Laboratory for Experimental Neuroregeneration, Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Andreas Schwarz
- Laboratory for Experimental Neurorehabilitation, Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Carlo Antonio Beretta
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Yvonne Schwarte
- Laboratory for Experimental Neuroregeneration, Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Francesca Schmitt
- Laboratory for Experimental Neuroregeneration, Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Melanie Motsch
- Laboratory for Experimental Neuroregeneration, Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Norbert Weidner
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Radhika Puttagunta
- Laboratory for Experimental Neuroregeneration, Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
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11
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Tomatsu S, Kim G, Kubota S, Seki K. Presynaptic gating of monkey proprioceptive signals for proper motor action. Nat Commun 2023; 14:6537. [PMID: 37880215 PMCID: PMC10600222 DOI: 10.1038/s41467-023-42077-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 09/28/2023] [Indexed: 10/27/2023] Open
Abstract
Our rich behavioural repertoire is supported by complicated synaptic connectivity in the central nervous system, which must be modulated to prevent behavioural control from being overwhelmed. For this modulation, presynaptic inhibition is an efficient mechanism because it can gate specific synaptic input without interfering with main circuit operations. Previously, we reported the task-dependent presynaptic inhibition of the cutaneous afferent input to the spinal cord in behaving monkeys. Here, we report presynaptic inhibition of the proprioceptive afferent input. We found that the input from shortened muscles is transiently facilitated, whereas that from lengthened muscles is persistently reduced. This presynaptic inhibition could be generated by cortical signals because it started before movement onset, and its size was correlated with the performance of stable motor output. Our findings demonstrate that presynaptic inhibition acts as a dynamic filter of proprioceptive signals, enabling the integration of task-relevant signals into spinal circuits.
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Affiliation(s)
- Saeka Tomatsu
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
- Division of Behavioral Development, Department of System Neuroscience, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa, Japan
| | - GeeHee Kim
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
- Division of Behavioral Development, Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo, Japan
| | - Shinji Kubota
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Kazuhiko Seki
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
- Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa, Japan.
- Division of Behavioral Development, Department of Developmental Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, Japan.
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12
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Lin S, Hari K, Black S, Khatmi A, Fouad K, Gorassini MA, Li Y, Lucas-Osma AM, Fenrich KK, Bennett DJ. Locomotor-related propriospinal V3 neurons produce primary afferent depolarization and modulate sensory transmission to motoneurons. J Neurophysiol 2023; 130:799-823. [PMID: 37609680 PMCID: PMC10650670 DOI: 10.1152/jn.00482.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 08/24/2023] Open
Abstract
When a muscle is stretched, sensory feedback not only causes reflexes but also leads to a depolarization of sensory afferents throughout the spinal cord (primary afferent depolarization, PAD), readying the whole limb for further disturbances. This sensory-evoked PAD is thought to be mediated by a trisynaptic circuit, where sensory input activates first-order excitatory neurons that activate GABAergic neurons that in turn activate GABAA receptors on afferents to cause PAD, though the identity of these first-order neurons is unclear. Here, we show that these first-order neurons include propriospinal V3 neurons, as they receive extensive sensory input and in turn innervate GABAergic neurons that cause PAD, because optogenetic activation or inhibition of V3 neurons in mice mimics or inhibits sensory-evoked PAD, respectively. Furthermore, persistent inward sodium currents intrinsic to V3 neurons prolong their activity, explaining the prolonged duration of PAD. Also, local optogenetic activation of V3 neurons at one segment causes PAD in other segments, due to the long propriospinal tracts of these neurons, helping to explain the radiating nature of PAD. This in turn facilitates monosynaptic reflex transmission to motoneurons across the spinal cord. In addition, V3 neurons directly innervate proprioceptive afferents (including Ia), causing a glutamate receptor-mediated PAD (glutamate PAD). Finally, increasing the spinal cord excitability with either GABAA receptor blockers or chronic spinal cord injury causes an increase in the glutamate PAD. Overall, we show the V3 neuron has a prominent role in modulating sensory transmission, in addition to its previously described role in locomotion.NEW & NOTEWORTHY Locomotor-related propriospinal neurons depolarize sensory axons throughout the spinal cord by either direct glutamatergic axoaxonic contacts or indirect innervation of GABAergic neurons that themselves form axoaxonic contacts on sensory axons. This depolarization (PAD) increases sensory transmission to motoneurons throughout the spinal cord, readying the sensorimotor system for external disturbances. The glutamate-mediated PAD is particularly adaptable, increasing with either an acute block of GABA receptors or chronic spinal cord injury, suggesting a role in motor recovery.
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Affiliation(s)
- Shihao Lin
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Krishnapriya Hari
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Sophie Black
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Aysan Khatmi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Karim Fouad
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Monica A Gorassini
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yaqing Li
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Ana M Lucas-Osma
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Keith K Fenrich
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - David J Bennett
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
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13
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Dallmann CJ, Dickerson BH, Simpson JH, Wyart C, Jayaram K. Mechanosensory Control of Locomotion in Animals and Robots: Moving Forward. Integr Comp Biol 2023; 63:450-463. [PMID: 37279901 PMCID: PMC10445419 DOI: 10.1093/icb/icad057] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/10/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023] Open
Abstract
While animals swim, crawl, walk, and fly with apparent ease, building robots capable of robust locomotion remains a significant challenge. In this review, we draw attention to mechanosensation-the sensing of mechanical forces generated within and outside the body-as a key sense that enables robust locomotion in animals. We discuss differences between mechanosensation in animals and current robots with respect to (1) the encoding properties and distribution of mechanosensors and (2) the integration and regulation of mechanosensory feedback. We argue that robotics would benefit greatly from a detailed understanding of these aspects in animals. To that end, we highlight promising experimental and engineering approaches to study mechanosensation, emphasizing the mutual benefits for biologists and engineers that emerge from moving forward together.
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Affiliation(s)
- Chris J Dallmann
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Bradley H Dickerson
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Julie H Simpson
- Department of Molecular, Cellular, and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Claire Wyart
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, Paris 75005, France
| | - Kaushik Jayaram
- Paul M Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
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14
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Murray GC, Bubier JA, Zinder OJ, Harris B, Clark J, Christopher MC, Hanley C, Tjong H, Li M, Ngan CY, Reinholdt L, Burgess RW, Tadenev ALD. An allelic series of spontaneous Rorb mutant mice exhibit a gait phenotype, changes in retina morphology and behavior, and gene expression signatures associated with the unfolded protein response. G3 (BETHESDA, MD.) 2023; 13:jkad131. [PMID: 37300435 PMCID: PMC10411600 DOI: 10.1093/g3journal/jkad131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
The Retinoid-related orphan receptor beta (RORβ) gene encodes a developmental transcription factor and has 2 predominant isoforms created through alternative first exon usage; one specific to the retina and another present more broadly in the central nervous system, particularly regions involved in sensory processing. RORβ belongs to the nuclear receptor family and plays important roles in cell fate specification in the retina and cortical layer formation. In mice, loss of RORβ causes disorganized retina layers, postnatal degeneration, and production of immature cone photoreceptors. Hyperflexion or "high-stepping" of rear limbs caused by reduced presynaptic inhibition by Rorb-expressing inhibitory interneurons of the spinal cord is evident in RORβ-deficient mice. RORβ variants in patients are associated with susceptibility to various neurodevelopmental conditions, primarily generalized epilepsies, but including intellectual disability, bipolar, and autism spectrum disorders. The mechanisms by which RORβ variants confer susceptibility to these neurodevelopmental disorders are unknown but may involve aberrant neural circuit formation and hyperexcitability during development. Here we report an allelic series in 5 strains of spontaneous Rorb mutant mice with a high-stepping gait phenotype. We show retinal abnormalities in a subset of these mutants and demonstrate significant differences in various behavioral phenotypes related to cognition. Gene expression analyses in all 5 mutants reveal a shared over-representation of the unfolded protein response and pathways related to endoplasmic reticulum stress, suggesting a possible mechanism of susceptibility relevant to patients.
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Affiliation(s)
- George C Murray
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | | | | | | | - James Clark
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | | | | | - Harianto Tjong
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Meihong Li
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Chew Yee Ngan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | | | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
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15
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Bohic M, Upadhyay A, Eisdorfer JT, Keating J, Simon RC, Briones BA, Azadegan C, Nacht HD, Oputa O, Martinez AM, Bethell BN, Gradwell MA, Romanienko P, Ramer MS, Stuber GD, Abraira VE. A new Hoxb8FlpO mouse line for intersectional approaches to dissect developmentally defined adult sensorimotor circuits. Front Mol Neurosci 2023; 16:1176823. [PMID: 37603775 PMCID: PMC10437123 DOI: 10.3389/fnmol.2023.1176823] [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: 02/28/2023] [Accepted: 07/04/2023] [Indexed: 08/23/2023] Open
Abstract
Improvements in the speed and cost of expression profiling of neuronal tissues offer an unprecedented opportunity to define ever finer subgroups of neurons for functional studies. In the spinal cord, single cell RNA sequencing studies support decades of work on spinal cord lineage studies, offering a unique opportunity to probe adult function based on developmental lineage. While Cre/Flp recombinase intersectional strategies remain a powerful tool to manipulate spinal neurons, the field lacks genetic tools and strategies to restrict manipulations to the adult mouse spinal cord at the speed at which new tools develop. This study establishes a new workflow for intersectional mouse-viral strategies to dissect adult spinal function based on developmental lineages in a modular fashion. To restrict manipulations to the spinal cord, we generate a brain-sparing Hoxb8FlpO mouse line restricting Flp recombinase expression to caudal tissue. Recapitulating endogenous Hoxb8 gene expression, Flp-dependent reporter expression is present in the caudal embryo starting day 9.5. This expression restricts Flp activity in the adult to the caudal brainstem and below. Hoxb8FlpO heterozygous and homozygous mice do not develop any of the sensory or locomotor phenotypes evident in Hoxb8 heterozygous or mutant animals, suggesting normal developmental function of the Hoxb8 gene and protein in Hoxb8FlpO mice. Compared to the variability of brain recombination in available caudal Cre and Flp lines, Hoxb8FlpO activity is not present in the brain above the caudal brainstem, independent of mouse genetic background. Lastly, we combine the Hoxb8FlpO mouse line with dorsal horn developmental lineage Cre mouse lines to express GFP in developmentally determined dorsal horn populations. Using GFP-dependent Cre recombinase viruses and Cre recombinase-dependent inhibitory chemogenetics, we target developmentally defined lineages in the adult. We show how developmental knock-out versus transient adult silencing of the same ROR𝛃 lineage neurons affects adult sensorimotor behavior. In summary, this new mouse line and viral approach provides a blueprint to dissect adult somatosensory circuit function using Cre/Flp genetic tools to target spinal cord interneurons based on genetic lineage.
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Affiliation(s)
- Manon Bohic
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Aman Upadhyay
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- Neuroscience PhD Program at Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States
| | - Jaclyn T. Eisdorfer
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Jessica Keating
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- School of Medicine, Oregon Health and Science University, Portland, OR, United States
- M.D./PhD Program in Neuroscience, School of Medicine, Oregon Health and Science University, Portland, OR, United States
| | - Rhiana C. Simon
- Center for the Neurobiology of Addiction, Pain, and Emotion, Department of Anesthesiology and Pain Medicine, Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Brandy A. Briones
- Center for the Neurobiology of Addiction, Pain, and Emotion, Department of Anesthesiology and Pain Medicine, Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Chloe Azadegan
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Hannah D. Nacht
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Olisemeka Oputa
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Alana M. Martinez
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Bridget N. Bethell
- International Collaboration on Repair Discoveries and Department of Zoology, The University of British Columbia, Vancouver, BC, Canada
| | - Mark A. Gradwell
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
| | - Peter Romanienko
- Genome Editing Shared Resource, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, United States
| | - Matt S. Ramer
- International Collaboration on Repair Discoveries and Department of Zoology, The University of British Columbia, Vancouver, BC, Canada
| | - Garret D. Stuber
- Center for the Neurobiology of Addiction, Pain, and Emotion, Department of Anesthesiology and Pain Medicine, Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Victoria E. Abraira
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, Piscataway, NJ, United States
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16
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Davis OC, Dickie AC, Mustapa MB, Boyle KA, Browne TJ, Gradwell MA, Smith KM, Polgár E, Bell AM, Kókai É, Watanabe M, Wildner H, Zeilhofer HU, Ginty DD, Callister RJ, Graham BA, Todd AJ, Hughes DI. Calretinin-expressing islet cells are a source of pre- and post-synaptic inhibition of non-peptidergic nociceptor input to the mouse spinal cord. Sci Rep 2023; 13:11561. [PMID: 37464016 PMCID: PMC10354228 DOI: 10.1038/s41598-023-38605-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/11/2023] [Indexed: 07/20/2023] Open
Abstract
Unmyelinated non-peptidergic nociceptors (NP afferents) arborise in lamina II of the spinal cord and receive GABAergic axoaxonic synapses, which mediate presynaptic inhibition. However, until now the source of this axoaxonic synaptic input was not known. Here we provide evidence that it originates from a population of inhibitory calretinin-expressing interneurons (iCRs), which correspond to lamina II islet cells. The NP afferents can be assigned to 3 functionally distinct classes (NP1-3). NP1 afferents have been implicated in pathological pain states, while NP2 and NP3 afferents also function as pruritoceptors. Our findings suggest that all 3 of these afferent types innervate iCRs and receive axoaxonic synapses from them, providing feedback inhibition of NP input. The iCRs also form axodendritic synapses, and their targets include cells that are themselves innervated by the NP afferents, thus allowing for feedforward inhibition. The iCRs are therefore ideally placed to control the input from non-peptidergic nociceptors and pruritoceptors to other dorsal horn neurons, and thus represent a potential therapeutic target for the treatment of chronic pain and itch.
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Affiliation(s)
- Olivia C Davis
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Allen C Dickie
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Marami B Mustapa
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
- Faculty of Medicine and Defence Health, National Defence University of Malaysia, 57000, Kuala Lumpur, Malaysia
| | - Kieran A Boyle
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Tyler J Browne
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Mark A Gradwell
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Kelly M Smith
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Erika Polgár
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andrew M Bell
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Éva Kókai
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, 060-8638, Japan
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zürich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zürich, Switzerland
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA, 02115, USA
| | - Robert J Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Brett A Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.
| | - Andrew J Todd
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - David I Hughes
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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17
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Davis OC, Dickie AC, Mustapa MB, Boyle KA, Browne TJ, Gradwell MA, Smith KM, Polgár E, Bell AM, Kókai É, Watanabe M, Wildner H, Zeilhofer HU, Ginty DD, Callister RJ, Graham BA, Todd AJ, Hughes DI. Calretinin-expressing islet cells: a source of pre- and post-synaptic inhibition of non-peptidergic nociceptor input to the mouse spinal cord. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.01.543241. [PMID: 37333120 PMCID: PMC10274676 DOI: 10.1101/2023.06.01.543241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Unmyelinated non-peptidergic nociceptors (NP afferents) arborise in lamina II of the spinal cord and receive GABAergic axoaxonic synapses, which mediate presynaptic inhibition. However, until now the source of this axoaxonic synaptic input was not known. Here we provide evidence that it originates from a population of inhibitory calretinin-expressing interneurons (iCRs), which correspond to lamina II islet cells. The NP afferents can be assigned to 3 functionally distinct classes (NP1-3). NP1 afferents have been implicated in pathological pain states, while NP2 and NP3 afferents also function as pruritoceptors. Our findings suggest that all 3 of these afferent types innervate iCRs and receive axoaxonic synapses from them, providing feedback inhibition of NP input. The iCRs also form axodendritic synapses, and their targets include cells that are themselves innervated by the NP afferents, thus allowing for feedforward inhibition. The iCRs are therefore ideally placed to control the input from non-peptidergic nociceptors and pruritoceptors to other dorsal horn neurons, and thus represent a potential therapeutic target for the treatment of chronic pain and itch.
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Affiliation(s)
- Olivia C. Davis
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Allen C. Dickie
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Marami B. Mustapa
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
- Present address: Faculty of Medicine and Defence Health, National Defence University of Malaysia, 57000, Kuala Lumpur, Malaysia
| | - Kieran A. Boyle
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Tyler J. Browne
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Mark A. Gradwell
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Kelly M. Smith
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Erika Polgár
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andrew M. Bell
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Éva Kókai
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
| | - David D. Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Robert J. Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Brett A. Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Andrew J. Todd
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - David I. Hughes
- School of Psychology and Neuroscience, Sir James Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
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18
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Tasnim A, Alkislar I, Hakim R, Turecek J, Abdelaziz A, Orefice LL, Ginty DD. The developmental timing of spinal touch processing alterations and its relation to ASD-associated behaviors in mouse models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.539589. [PMID: 37214862 PMCID: PMC10197556 DOI: 10.1101/2023.05.09.539589] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Altered somatosensory reactivity is frequently observed among individuals with autism spectrum disorders (ASDs). Here, we report that while multiple mouse models of ASD exhibit aberrant somatosensory behaviors in adulthood, some models exhibit altered tactile reactivity as early as embryonic development, while in others, altered reactivity emerges later in life. Additionally, tactile over-reactivity during neonatal development is associated with anxiety-like behaviors and social interaction deficits in adulthood, whereas tactile over-reactivity that emerges later in life is not. The locus of circuit disruption dictates the timing of aberrant tactile behaviors: altered feedback or presynaptic inhibition of peripheral mechanosensory neurons leads to abnormal tactile reactivity during neonatal development, while disruptions in feedforward inhibition in the spinal cord lead to touch reactivity alterations that manifest later in life. Thus, the developmental timing of aberrant touch processing can predict the manifestation of ASD-associated behaviors in mouse models, and differential timing of sensory disturbance onset may contribute to phenotypic diversity across individuals with ASD.
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19
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Wilson AC, Sweeney LB. Spinal cords: Symphonies of interneurons across species. Front Neural Circuits 2023; 17:1146449. [PMID: 37180760 PMCID: PMC10169611 DOI: 10.3389/fncir.2023.1146449] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/23/2023] [Indexed: 05/16/2023] Open
Abstract
Vertebrate movement is orchestrated by spinal inter- and motor neurons that, together with sensory and cognitive input, produce dynamic motor behaviors. These behaviors vary from the simple undulatory swimming of fish and larval aquatic species to the highly coordinated running, reaching and grasping of mice, humans and other mammals. This variation raises the fundamental question of how spinal circuits have changed in register with motor behavior. In simple, undulatory fish, exemplified by the lamprey, two broad classes of interneurons shape motor neuron output: ipsilateral-projecting excitatory neurons, and commissural-projecting inhibitory neurons. An additional class of ipsilateral inhibitory neurons is required to generate escape swim behavior in larval zebrafish and tadpoles. In limbed vertebrates, a more complex spinal neuron composition is observed. In this review, we provide evidence that movement elaboration correlates with an increase and specialization of these three basic interneuron types into molecularly, anatomically, and functionally distinct subpopulations. We summarize recent work linking neuron types to movement-pattern generation across fish, amphibians, reptiles, birds and mammals.
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Affiliation(s)
| | - Lora B. Sweeney
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Lower Austria, Austria
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20
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Worley A, Kirby A, Luks S, Samardzic T, Ellison B, Broom L, Latremoliere A, VanderHorst VG. Contrasting walking styles map to discrete neural substrates in the mouse brainstem. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537568. [PMID: 37131768 PMCID: PMC10153272 DOI: 10.1101/2023.04.19.537568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Walking is a slow gait which is particularly adaptable to meet internal or external needs and is prone to maladaptive alterations that lead to gait disorders. Alterations can affect speed, but also style (the way one walks). While slowed speed may signify the presence of a problem, style represents the hallmark essential for clinical classification of gait disorders. However, it has been challenging to objectively capture key stylistic features while uncovering neural substrates driving these features. Here we revealed brainstem hotspots that drive strikingly different walking styles by employing an unbiased mapping assay that combines quantitative walking signatures with focal, cell type specific activation. We found that activation of inhibitory neurons that mapped to the ventromedial caudal pons induced slow motion-like style. Activation of excitatory neurons that mapped to the ventromedial upper medulla induced shuffle-like style. Contrasting shifts in walking signatures distinguished these styles. Activation of inhibitory and excitatory neurons outside these territories or of serotonergic neurons modulated walking speed, but without walking signature shifts. Consistent with their contrasting modulatory actions, hotspots for slow-motion and shuffle-like gaits preferentially innervated different substrates. These findings lay the basis for new avenues to study mechanisms underlying (mal)adaptive walking styles and gait disorders. Graphical abstract
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21
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Rankin G, Chirila AM, Emanuel AJ, Zhang Z, Woolf CJ, Drugowitsch J, Ginty DD. Nerve injury disrupts temporal processing in the spinal cord dorsal horn through alterations in PV + interneurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.20.533541. [PMID: 36993199 PMCID: PMC10055222 DOI: 10.1101/2023.03.20.533541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
How mechanical allodynia following nerve injury is encoded in patterns of neural activity in the spinal cord dorsal horn (DH) is not known. We addressed this using the spared nerve injury model of neuropathic pain and in vivo electrophysiological recordings. Surprisingly, despite dramatic behavioral over-reactivity to mechanical stimuli following nerve injury, an overall increase in sensitivity or reactivity of DH neurons was not observed. We did, however, observe a marked decrease in correlated neural firing patterns, including the synchrony of mechanical stimulus-evoked firing, across the DH. Alterations in DH temporal firing patterns were recapitulated by silencing DH parvalbumin + (PV + ) inhibitory interneurons, previously implicated in mechanical allodynia, as were allodynic pain-like behaviors in mice. These findings reveal decorrelated DH network activity, driven by alterations in PV + interneurons, as a prominent feature of neuropathic pain, and suggest that restoration of proper temporal activity is a potential treatment for chronic neuropathic pain.
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22
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Human spinal GABA neurons survive and mature in the injured nonhuman primate spinal cord. Stem Cell Reports 2023; 18:439-448. [PMID: 36669493 PMCID: PMC9969075 DOI: 10.1016/j.stemcr.2022.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/18/2022] [Accepted: 12/20/2022] [Indexed: 01/20/2023] Open
Abstract
Spinal cord injury (SCI) leads to permanent neural dysfunction without effective therapies. We previously showed that human pluripotent stem cell (hPSC)-derived spinal GABA neurons can alleviate spasticity and promote locomotion in rats after SCI, but whether this strategy can be translated into the clinic remains elusive. Here, a nonhuman primate (NHP) model of SCI was established in rhesus macaques (Macaca mulatta) in which the T10 spinal cord was hemisected, resulting in neural conduction failure and neural dysfunction, including locomotion deficits, pain, and spasms. Grafted human spinal GABA neurons survived for up to 7.5 months in the injured monkey spinal cord and retained their intrinsic properties, becoming mature and growing axons and forming synapses. Importantly, they are functionally alive, as evidenced by designer receptors exclusively activated by designer drug (DREADD) activation. These findings represent a significant step toward the clinical translation of human spinal neuron transplantation for treating SCI.
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23
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Banerjee T, Pati S, Tiwari P, Vaidya VA. Chronic hM3Dq-DREADD-mediated chemogenetic activation of parvalbumin-positive inhibitory interneurons in postnatal life alters anxiety and despair-like behavior in adulthood in a task- and sex-dependent manner. J Biosci 2022. [DOI: 10.1007/s12038-022-00308-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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24
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Chirila AM, Rankin G, Tseng SY, Emanuel AJ, Chavez-Martinez CL, Zhang D, Harvey CD, Ginty DD. Mechanoreceptor signal convergence and transformation in the dorsal horn flexibly shape a diversity of outputs to the brain. Cell 2022; 185:4541-4559.e23. [PMID: 36334588 PMCID: PMC9691598 DOI: 10.1016/j.cell.2022.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/22/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022]
Abstract
The encoding of touch in the spinal cord dorsal horn (DH) and its influence on tactile representations in the brain are poorly understood. Using a range of mechanical stimuli applied to the skin, large-scale in vivo electrophysiological recordings, and genetic manipulations, here we show that neurons in the mouse spinal cord DH receive convergent inputs from both low- and high-threshold mechanoreceptor subtypes and exhibit one of six functionally distinct mechanical response profiles. Genetic disruption of DH feedforward or feedback inhibitory motifs, comprised of interneurons with distinct mechanical response profiles, revealed an extensively interconnected DH network that enables dynamic, flexible tuning of postsynaptic dorsal column (PSDC) output neurons and dictates how neurons in the primary somatosensory cortex respond to touch. Thus, mechanoreceptor subtype convergence and non-linear transformations at the earliest stage of the somatosensory hierarchy shape how touch of the skin is represented in the brain.
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Affiliation(s)
- Anda M Chirila
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Genelle Rankin
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Shih-Yi Tseng
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Alan J Emanuel
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Carmine L Chavez-Martinez
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Dawei Zhang
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Christopher D Harvey
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - David D Ginty
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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25
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Spinal Cord Circuits: Models and Reality. NEUROPHYSIOLOGY+ 2022. [DOI: 10.1007/s11062-022-09927-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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26
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Gebehart C, Hooper SL, Büschges A. Non-linear multimodal integration in a distributed premotor network controls proprioceptive reflex gain in the insect leg. Curr Biol 2022; 32:3847-3854.e3. [PMID: 35896118 DOI: 10.1016/j.cub.2022.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/30/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022]
Abstract
Producing context-appropriate motor acts requires integrating multiple sensory modalities. Presynaptic inhibition of proprioceptive afferent neurons1-4 and afferents of different modalities targeting the same motor neurons (MNs)5-7 underlies some of this integration. However, in most systems, an interneuronal network is interposed between sensory afferents and MNs. How these networks contribute to this integration, particularly at single-neuron resolution, is little understood. Context-specific integration of load and movement sensory inputs occurs in the stick insect locomotory system,6,8-12 and both inputs feed into a network of premotor nonspiking interneurons (NSIs).8 We analyzed how load altered movement signal processing in the stick insect femur-tibia (FTi) joint control system by tracing the interaction of FTi movement13-15 (femoral chordotonal organ [fCO]) and load13,15,16 (tibial campaniform sensilla [CS]) signals through the NSI network to the slow extensor tibiae (SETi) MN, the extensor MN primarily active in non-walking animals.17-19 On the afferent level, load reduced movement signal gain by presynaptic inhibition. In the NSI network, graded responses to movement and load inputs summed nonlinearly, increasing the gain of NSIs opposing movement-induced reflexes and thus decreasing the SETi and extensor tibiae muscle movement reflex responses. Gain modulation was movement-parameter specific and required presynaptic inhibition. These data suggest that gain changes in distributed premotor networks, specifically the relative weighting of antagonistic pathways, could be a general mechanism by which multiple sensory modalities are integrated to generate context-appropriate motor activity.
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Affiliation(s)
- Corinna Gebehart
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Strasse 47b, 50674 Cologne, Germany.
| | - Scott L Hooper
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Strasse 47b, 50674 Cologne, Germany; Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Ansgar Büschges
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, Zülpicher Strasse 47b, 50674 Cologne, Germany
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27
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Kasatkina LA, Verkhusha VV. Transgenic mice encoding modern imaging probes: Properties and applications. Cell Rep 2022; 39:110845. [PMID: 35613592 PMCID: PMC9183799 DOI: 10.1016/j.celrep.2022.110845] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/31/2022] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
Modern biology is increasingly reliant on optical technologies, including visualization and longitudinal monitoring of cellular processes. The major limitation here is the availability of animal models to track the molecules and cells in their natural environment in vivo. Owing to the integrity of the studied tissue and the high stability of transgene expression throughout life, transgenic mice encoding fluorescent proteins and biosensors represent unique tools for in vivo studies in norm and pathology. We review the strategies for targeting probe expression in specific tissues, cell subtypes, or cellular compartments. We describe the application of transgenic mice expressing fluorescent proteins for tracking protein expression patterns, apoptotic events, tissue differentiation and regeneration, neurogenesis, tumorigenesis, and cell fate mapping. We overview the possibilities of functional imaging of secondary messengers, neurotransmitters, and ion fluxes. Finally, we provide the rationale and perspectives for the use of transgenic imaging probes in translational research and drug discovery.
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Affiliation(s)
- Ludmila A Kasatkina
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Vladislav V Verkhusha
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Medicum, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland.
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28
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Parallel locomotor control strategies in mice and flies. Curr Opin Neurobiol 2022; 73:102516. [DOI: 10.1016/j.conb.2022.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/23/2021] [Accepted: 01/06/2022] [Indexed: 12/26/2022]
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29
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Cook JR, Li H, Nguyen B, Huang HH, Mahdavian P, Kirchgessner MA, Strassmann P, Engelhardt M, Callaway EM, Jin X. Secondary auditory cortex mediates a sensorimotor mechanism for action timing. Nat Neurosci 2022; 25:330-344. [PMID: 35260862 DOI: 10.1038/s41593-022-01025-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 01/26/2022] [Indexed: 01/08/2023]
Abstract
The ability to accurately determine when to perform an action is a fundamental brain function and vital to adaptive behavior. The behavioral mechanism and neural circuit for action timing, however, remain largely unknown. Using a new, self-paced action timing task in mice, we found that deprivation of auditory, but not somatosensory or visual input, disrupts learned action timing. The hearing effect was dependent on the auditory feedback derived from the animal's own actions, rather than passive environmental cues. Neuronal activity in the secondary auditory cortex was found to be both correlated with and necessary for the proper execution of learned action timing. Closed-loop, action-dependent optogenetic stimulation of the specific task-related neuronal population within the secondary auditory cortex rescued the key features of learned action timing under auditory deprivation. These results unveil a previously underappreciated sensorimotor mechanism in which the secondary auditory cortex transduces self-generated audiomotor feedback to control action timing.
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Affiliation(s)
- Jonathan R Cook
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA.,Champalimaud Centre for the Unknown, Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Hao Li
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Bella Nguyen
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Hsiang-Hsuan Huang
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Payaam Mahdavian
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Megan A Kirchgessner
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA.,Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | - Patrick Strassmann
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.,Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Max Engelhardt
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Edward M Callaway
- Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Xin Jin
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA. .,Center for Motor Control and Disease, Key Laboratory of Brain Functional Genomics, East China Normal University, Shanghai, China. .,NYU-ECNU Institute of Brain and Cognitive Science, New York University Shanghai, Shanghai, China.
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30
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Laliberte AM, Farah C, Steiner KR, Tariq O, Bui TV. Changes in Sensorimotor Connectivity to dI3 Interneurons in Relation to the Postnatal Maturation of Grasping. Front Neural Circuits 2022; 15:768235. [PMID: 35153680 PMCID: PMC8828486 DOI: 10.3389/fncir.2021.768235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/31/2021] [Indexed: 11/23/2022] Open
Abstract
Primitive reflexes are evident shortly after birth. Many of these reflexes disappear during postnatal development as part of the maturation of motor control. This study investigates the changes of connectivity related to sensory integration by spinal dI3 interneurons during the time in which the palmar grasp reflex gradually disappears in postnatal mice pups. Our results reveal an increase in GAD65/67-labeled terminals to perisomatic Vglut1-labeled sensory inputs contacting cervical and lumbar dI3 interneurons between postnatal day 3 and day 25. In contrast, there were no changes in the number of perisomatic Vglut1-labeled sensory inputs to lumbar and cervical dI3 interneurons other than a decrease between postnatal day 15 and day 25. Changes in postsynaptic GAD65/67-labeled inputs to dI3 interneurons were inconsistent with a role in the sustained loss of the grasp reflex. These results suggest a possible link between the maturation of hand grasp during postnatal development and increased presynaptic inhibition of sensory inputs to dI3 interneurons.
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Affiliation(s)
- Alex M. Laliberte
- Brain and Mind Research Institute, Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Carl Farah
- Brain and Mind Research Institute, Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kyra R. Steiner
- Brain and Mind Research Institute, Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Omar Tariq
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Tuan V. Bui
- Brain and Mind Research Institute, Department of Biology, University of Ottawa, Ottawa, ON, Canada
- *Correspondence: Tuan V. Bui
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31
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Dasen JS. Establishing the Molecular and Functional Diversity of Spinal Motoneurons. ADVANCES IN NEUROBIOLOGY 2022; 28:3-44. [PMID: 36066819 DOI: 10.1007/978-3-031-07167-6_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Spinal motoneurons are a remarkably diverse class of neurons responsible for facilitating a broad range of motor behaviors and autonomic functions. Studies of motoneuron differentiation have provided fundamental insights into the developmental mechanisms of neuronal diversification, and have illuminated principles of neural fate specification that operate throughout the central nervous system. Because of their relative anatomical simplicity and accessibility, motoneurons have provided a tractable model system to address multiple facets of neural development, including early patterning, neuronal migration, axon guidance, and synaptic specificity. Beyond their roles in providing direct communication between central circuits and muscle, recent studies have revealed that motoneuron subtype-specific programs also play important roles in determining the central connectivity and function of motor circuits. Cross-species comparative analyses have provided novel insights into how evolutionary changes in subtype specification programs may have contributed to adaptive changes in locomotor behaviors. This chapter focusses on the gene regulatory networks governing spinal motoneuron specification, and how studies of spinal motoneurons have informed our understanding of the basic mechanisms of neuronal specification and spinal circuit assembly.
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Affiliation(s)
- Jeremy S Dasen
- NYU Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA.
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32
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Nicola FDC, Hua I, Levine AJ. Intersectional genetic tools to study skilled reaching in mice. Exp Neurol 2021; 347:113879. [PMID: 34597682 DOI: 10.1016/j.expneurol.2021.113879] [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] [Received: 08/02/2021] [Revised: 09/10/2021] [Accepted: 09/24/2021] [Indexed: 11/25/2022]
Abstract
Reaching to grasp is an evolutionarily conserved behavior and a crucial part of the motor repertoire in mammals. As it is studied in the laboratory, reaching has become the prototypical example of dexterous forelimb movements, illuminating key principles of motor control throughout the spinal cord, brain, and peripheral nervous system. Here, we (1) review the motor elements or phases that comprise the reach, grasp, and retract movements of reaching behavior, (2) highlight the role of intersectional genetic tools in linking these movements to their neuronal substrates, (3) describe spinal cord cell types and their roles in skilled reaching, and (4) how descending pathways from the brain and the sensory systems contribute to skilled reaching. We emphasize that genetic perturbation experiments can pin-point the neuronal substrates of specific phases of reaching behavior.
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Affiliation(s)
- Fabricio do Couto Nicola
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Isabelle Hua
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States of America
| | - Ariel J Levine
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States of America.
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33
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Russ DE, Cross RBP, Li L, Koch SC, Matson KJE, Yadav A, Alkaslasi MR, Lee DI, Le Pichon CE, Menon V, Levine AJ. A harmonized atlas of mouse spinal cord cell types and their spatial organization. Nat Commun 2021; 12:5722. [PMID: 34588430 PMCID: PMC8481483 DOI: 10.1038/s41467-021-25125-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 07/21/2021] [Indexed: 12/12/2022] Open
Abstract
Single-cell RNA sequencing data can unveil the molecular diversity of cell types. Cell type atlases of the mouse spinal cord have been published in recent years but have not been integrated together. Here, we generate an atlas of spinal cell types based on single-cell transcriptomic data, unifying the available datasets into a common reference framework. We report a hierarchical structure of postnatal cell type relationships, with location providing the highest level of organization, then neurotransmitter status, family, and finally, dozens of refined populations. We validate a combinatorial marker code for each neuronal cell type and map their spatial distributions in the adult spinal cord. We also show complex lineage relationships among postnatal cell types. Additionally, we develop an open-source cell type classifier, SeqSeek, to facilitate the standardization of cell type identification. This work provides an integrated view of spinal cell types, their gene expression signatures, and their molecular organization.
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Affiliation(s)
- Daniel E Russ
- Division of Cancer Epidemiology and Genetics, Data Science Research Group, National Cancer Institute, NIH, Rockville, MD, USA
| | - Ryan B Patterson Cross
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Li Li
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Stephanie C Koch
- Department of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London, UK
| | - Kaya J E Matson
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Archana Yadav
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Columbia University, New York, NY, USA
| | - Mor R Alkaslasi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA.,Department of Neuroscience, Brown University, Providence, RI, USA
| | - Dylan I Lee
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Columbia University, New York, NY, USA
| | - Claire E Le Pichon
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Vilas Menon
- Department of Neurology, Center for Translational and Computational Neuroimmunology, Columbia University, New York, NY, USA
| | - Ariel J Levine
- Spinal Circuits and Plasticity Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA.
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34
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Karashchuk P, Rupp KL, Dickinson ES, Walling-Bell S, Sanders E, Azim E, Brunton BW, Tuthill JC. Anipose: A toolkit for robust markerless 3D pose estimation. Cell Rep 2021; 36:109730. [PMID: 34592148 PMCID: PMC8498918 DOI: 10.1016/j.celrep.2021.109730] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 06/15/2021] [Accepted: 08/27/2021] [Indexed: 01/12/2023] Open
Abstract
Quantifying movement is critical for understanding animal behavior. Advances in computer vision now enable markerless tracking from 2D video, but most animals move in 3D. Here, we introduce Anipose, an open-source toolkit for robust markerless 3D pose estimation. Anipose is built on the 2D tracking method DeepLabCut, so users can expand their existing experimental setups to obtain accurate 3D tracking. It consists of four components: (1) a 3D calibration module, (2) filters to resolve 2D tracking errors, (3) a triangulation module that integrates temporal and spatial regularization, and (4) a pipeline to structure processing of large numbers of videos. We evaluate Anipose on a calibration board as well as mice, flies, and humans. By analyzing 3D leg kinematics tracked with Anipose, we identify a key role for joint rotation in motor control of fly walking. To help users get started with 3D tracking, we provide tutorials and documentation at http://anipose.org/.
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Affiliation(s)
- Pierre Karashchuk
- Neuroscience Graduate Program, University of Washington, Seattle, WA, USA
| | - Katie L. Rupp
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Evyn S. Dickinson
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Sarah Walling-Bell
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Elischa Sanders
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Bingni W. Brunton
- Department of Biology, University of Washington, Seattle, WA, USA,Senior author,Correspondence: (B.W.B.), (J.C.T.)
| | - John C. Tuthill
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA,Senior author,Lead contact,Correspondence: (B.W.B.), (J.C.T.)
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35
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Walker JR, Detloff MR. Plasticity in Cervical Motor Circuits following Spinal Cord Injury and Rehabilitation. BIOLOGY 2021; 10:biology10100976. [PMID: 34681075 PMCID: PMC8533179 DOI: 10.3390/biology10100976] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/17/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Spinal cord injury results in a decreased quality of life and impacts hundreds of thousands of people in the US alone. This review discusses the underlying cellular mechanisms of injury and the concurrent therapeutic hurdles that impede recovery. It then describes the phenomena of neural plasticity—the nervous system’s ability to change. The primary focus of the review is on the impact of cervical spinal cord injury on control of the upper limbs. The neural plasticity that occurs without intervention is discussed, which shows new connections growing around the injury site and the involvement of compensatory movements. Rehabilitation-driven neural plasticity is shown to have the ability to guide connections to create more normal functions. Various novel stimulation and recording technologies are outlined for their role in further improving rehabilitative outcomes and gains in independence. Finally, the importance of sensory input, an often-overlooked aspect of motor control, is shown in driving neural plasticity. Overall, this review seeks to delineate the historical and contemporary research into neural plasticity following injury and rehabilitation to guide future studies. Abstract Neuroplasticity is a robust mechanism by which the central nervous system attempts to adapt to a structural or chemical disruption of functional connections between neurons. Mechanical damage from spinal cord injury potentiates via neuroinflammation and can cause aberrant changes in neural circuitry known as maladaptive plasticity. Together, these alterations greatly diminish function and quality of life. This review discusses contemporary efforts to harness neuroplasticity through rehabilitation and neuromodulation to restore function with a focus on motor recovery following cervical spinal cord injury. Background information on the general mechanisms of plasticity and long-term potentiation of the nervous system, most well studied in the learning and memory fields, will be reviewed. Spontaneous plasticity of the nervous system, both maladaptive and during natural recovery following spinal cord injury is outlined to provide a baseline from which rehabilitation builds. Previous research has focused on the impact of descending motor commands in driving spinal plasticity. However, this review focuses on the influence of physical therapy and primary afferent input and interneuron modulation in driving plasticity within the spinal cord. Finally, future directions into previously untargeted primary afferent populations are presented.
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Miranda CO, Hegedüs K, Wildner H, Zeilhofer HU, Antal M. Morphological and neurochemical characterization of glycinergic neurons in laminae I-IV of the mouse spinal dorsal horn. J Comp Neurol 2021; 530:607-626. [PMID: 34382691 DOI: 10.1002/cne.25232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 08/04/2021] [Accepted: 08/09/2021] [Indexed: 12/18/2022]
Abstract
A growing body of experimental evidence shows that glycinergic inhibition plays vital roles in spinal pain processing. In spite of this, however, our knowledge about the morphology, neurochemical characteristics, and synaptic relations of glycinergic neurons in the spinal dorsal horn is very limited. The lack of this knowledge makes our understanding about the specific contribution of glycinergic neurons to spinal pain processing quite vague. Here we investigated the morphology and neurochemical characteristics of glycinergic neurons in laminae I-IV of the spinal dorsal horn using a GlyT2::CreERT2-tdTomato transgenic mouse line. Confirming previous reports, we show that glycinergic neurons are sparsely distributed in laminae I-II, but their densities are much higher in lamina III and especially in lamina IV. First in the literature, we provide experimental evidence indicating that in addition to neurons in which glycine colocalizes with GABA, there are glycinergic neurons in laminae I-II that do not express GABA and can thus be referred to as glycine-only neurons. According to the shape and size of cell bodies and dendritic morphology, we divided the tdTomato-labeled glycinergic neurons into three and six morphological groups in laminae I-II and laminae III-IV, respectively. We also demonstrate that most of the glycinergic neurons co-express neuronal nitric oxide synthase, parvalbumin, the receptor tyrosine kinase RET, and the retinoic acid-related orphan nuclear receptor β (RORβ), but there might be others that need further neurochemical characterization. The present findings may foster our understanding about the contribution of glycinergic inhibition to spinal pain processing.
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Affiliation(s)
- Camila Oliveira Miranda
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztina Hegedüs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Miklós Antal
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Computational Modeling of Spinal Locomotor Circuitry in the Age of Molecular Genetics. Int J Mol Sci 2021; 22:ijms22136835. [PMID: 34202085 PMCID: PMC8267724 DOI: 10.3390/ijms22136835] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/13/2022] Open
Abstract
Neuronal circuits in the spinal cord are essential for the control of locomotion. They integrate supraspinal commands and afferent feedback signals to produce coordinated rhythmic muscle activations necessary for stable locomotion. For several decades, computational modeling has complemented experimental studies by providing a mechanistic rationale for experimental observations and by deriving experimentally testable predictions. This symbiotic relationship between experimental and computational approaches has resulted in numerous fundamental insights. With recent advances in molecular and genetic methods, it has become possible to manipulate specific constituent elements of the spinal circuitry and relate them to locomotor behavior. This has led to computational modeling studies investigating mechanisms at the level of genetically defined neuronal populations and their interactions. We review literature on the spinal locomotor circuitry from a computational perspective. By reviewing examples leading up to and in the age of molecular genetics, we demonstrate the importance of computational modeling and its interactions with experiments. Moving forward, neuromechanical models with neuronal circuitry modeled at the level of genetically defined neuronal populations will be required to further unravel the mechanisms by which neuronal interactions lead to locomotor behavior.
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38
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Carneiro M, Vieillard J, Andrade P, Boucher S, Afonso S, Blanco-Aguiar JA, Santos N, Branco J, Esteves PJ, Ferrand N, Kullander K, Andersson L. A loss-of-function mutation in RORB disrupts saltatorial locomotion in rabbits. PLoS Genet 2021; 17:e1009429. [PMID: 33764968 PMCID: PMC7993613 DOI: 10.1371/journal.pgen.1009429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/17/2021] [Indexed: 11/18/2022] Open
Abstract
Saltatorial locomotion is a type of hopping gait that in mammals can be found in rabbits, hares, kangaroos, and some species of rodents. The molecular mechanisms that control and fine-tune the formation of this type of gait are unknown. Here, we take advantage of one strain of domesticated rabbits, the sauteur d'Alfort, that exhibits an abnormal locomotion behavior defined by the loss of the typical jumping that characterizes wild-type rabbits. Strikingly, individuals from this strain frequently adopt a bipedal gait using their front legs. Using a combination of experimental crosses and whole genome sequencing, we show that a single locus containing the RAR related orphan receptor B gene (RORB) explains the atypical gait of these rabbits. We found that a splice-site mutation in an evolutionary conserved site of RORB results in several aberrant transcript isoforms incorporating intronic sequence. This mutation leads to a drastic reduction of RORB-positive neurons in the spinal cord, as well as defects in differentiation of populations of spinal cord interneurons. Our results show that RORB function is required for the performance of saltatorial locomotion in rabbits.
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Affiliation(s)
- Miguel Carneiro
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
- * E-mail: (MC); (LA)
| | | | - Pedro Andrade
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Samuel Boucher
- Labovet Conseil (Réseau Cristal), Les Herbiers Cedex, France
| | - Sandra Afonso
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - José A. Blanco-Aguiar
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Nuno Santos
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - João Branco
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Pedro J. Esteves
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Nuno Ferrand
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
- Department of Zoology, Faculty of Sciences, University of Johannesburg, Auckland, South Africa
| | - Klas Kullander
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Leif Andersson
- Science for Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
- * E-mail: (MC); (LA)
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Spinal Inhibitory Interneurons: Gatekeepers of Sensorimotor Pathways. Int J Mol Sci 2021; 22:ijms22052667. [PMID: 33800863 PMCID: PMC7961554 DOI: 10.3390/ijms22052667] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/26/2021] [Accepted: 03/04/2021] [Indexed: 12/20/2022] Open
Abstract
The ability to sense and move within an environment are complex functions necessary for the survival of nearly all species. The spinal cord is both the initial entry site for peripheral information and the final output site for motor response, placing spinal circuits as paramount in mediating sensory responses and coordinating movement. This is partly accomplished through the activation of complex spinal microcircuits that gate afferent signals to filter extraneous stimuli from various sensory modalities and determine which signals are transmitted to higher order structures in the CNS and to spinal motor pathways. A mechanistic understanding of how inhibitory interneurons are organized and employed within the spinal cord will provide potential access points for therapeutics targeting inhibitory deficits underlying various pathologies including sensory and movement disorders. Recent studies using transgenic manipulations, neurochemical profiling, and single-cell transcriptomics have identified distinct populations of inhibitory interneurons which express an array of genetic and/or neurochemical markers that constitute functional microcircuits. In this review, we provide an overview of identified neural components that make up inhibitory microcircuits within the dorsal and ventral spinal cord and highlight the importance of inhibitory control of sensorimotor pathways at the spinal level.
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40
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Shadrach JL, Gomez-Frittelli J, Kaltschmidt JA. Proprioception revisited: where do we stand? CURRENT OPINION IN PHYSIOLOGY 2021; 21:23-28. [PMID: 34222735 DOI: 10.1016/j.cophys.2021.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Originally referred to as 'muscle sense', the notion that skeletal muscle held a peripheral sensory function was first described early in the 19th century. Foundational experiments by Sherrington in the early 20th century definitively demonstrated that proprioceptors contained within skeletal muscle, tendons, and joints are innervated by sensory neurons and play an important role in the control of movement. In this review, we will highlight several recent advances in the ongoing effort to further define the molecular diversity underlying the proprioceptive sensorimotor system. Together, the work summarized here represents our current understanding of sensorimotor circuit formation during development and the mechanisms that regulate the integration of proprioceptive feedback into the spinal circuits that control locomotion in both normal and diseased states.
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Affiliation(s)
- Jennifer L Shadrach
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
| | - Julieta Gomez-Frittelli
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA.,Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Julia A Kaltschmidt
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
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41
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Lalonde NR, Bui TV. Do spinal circuits still require gating of sensory information by presynaptic inhibition after spinal cord injury? CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2020.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Sensational developments in somatosensory development? Curr Opin Neurobiol 2021; 66:212-223. [PMID: 33454646 DOI: 10.1016/j.conb.2020.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/10/2020] [Accepted: 12/12/2020] [Indexed: 12/25/2022]
Abstract
This is an overview of the most recent advances pertaining to the development of the cardinal components of the somatosensory system: the peripheral sensory neurons that perceive somatosensory stimuli, the first line central nervous system circuits that modulate them, and the higher structures such as the somatosensory cortex that eventually compute a motor response to them. Here, I also review the most recent findings concerning the role of neuronal activity in somatosensory development, formation of somatotopic maps, insights into human somatosensory development and the link between aberrant somatosensation and neurodevelopmental disorders.
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43
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Gatto G, Bourane S, Ren X, Di Costanzo S, Fenton PK, Halder P, Seal RP, Goulding MD. A Functional Topographic Map for Spinal Sensorimotor Reflexes. Neuron 2021; 109:91-104.e5. [PMID: 33181065 PMCID: PMC7790959 DOI: 10.1016/j.neuron.2020.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/17/2020] [Accepted: 09/30/2020] [Indexed: 01/02/2023]
Abstract
Cutaneous somatosensory modalities play pivotal roles in generating a wide range of sensorimotor behaviors, including protective and corrective reflexes that dynamically adapt ongoing movement and posture. How interneurons (INs) in the dorsal horn encode these modalities and transform them into stimulus-appropriate motor behaviors is not known. Here, we use an intersectional genetic approach to functionally assess the contribution that eight classes of dorsal excitatory INs make to sensorimotor reflex responses. We demonstrate that the dorsal horn is organized into spatially restricted excitatory modules composed of molecularly heterogeneous cell types. Laminae I/II INs drive chemical itch-induced scratching, laminae II/III INs generate paw withdrawal movements, and laminae III/IV INs modulate dynamic corrective reflexes. These data reveal a key principle in spinal somatosensory processing, namely, sensorimotor reflexes are driven by the differential spatial recruitment of excitatory neurons.
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Affiliation(s)
- Graziana Gatto
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Steeve Bourane
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Université de la Réunion, DéTROI, UMR 1188 INSERM, Sainte Clotilde, La Réunion 97490, France
| | - Xiangyu Ren
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Biology Graduate Program, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stefania Di Costanzo
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Biology Graduate Program, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Peter K Fenton
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Priyabrata Halder
- Departments of Neurobiology and Otolaryngology, Center for Neural Basis of Cognition, and Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Rebecca P Seal
- Departments of Neurobiology and Otolaryngology, Center for Neural Basis of Cognition, and Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Martyn D Goulding
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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44
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Wu D, Jin Y, Shapiro TM, Hinduja A, Baas PW, Tom VJ. Chronic neuronal activation increases dynamic microtubules to enhance functional axon regeneration after dorsal root crush injury. Nat Commun 2020; 11:6131. [PMID: 33257677 PMCID: PMC7705672 DOI: 10.1038/s41467-020-19914-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 11/05/2020] [Indexed: 12/26/2022] Open
Abstract
After a dorsal root crush injury, centrally-projecting sensory axons fail to regenerate across the dorsal root entry zone (DREZ) to extend into the spinal cord. We find that chemogenetic activation of adult dorsal root ganglion (DRG) neurons improves axon growth on an in vitro model of the inhibitory environment after injury. Moreover, repeated bouts of daily chemogenetic activation of adult DRG neurons for 12 weeks post-crush in vivo enhances axon regeneration across a chondroitinase-digested DREZ into spinal gray matter, where the regenerating axons form functional synapses and mediate behavioral recovery in a sensorimotor task. Neuronal activation-mediated axon extension is dependent upon changes in the status of tubulin post-translational modifications indicative of highly dynamic microtubules (as opposed to stable microtubules) within the distal axon, illuminating a novel mechanism underlying stimulation-mediated axon growth. We have identified an effective combinatory strategy to promote functionally-relevant axon regeneration of adult neurons into the CNS after injury.
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Affiliation(s)
- Di Wu
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Ying Jin
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Tatiana M Shapiro
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Abhishek Hinduja
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA.
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45
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Ryczko D, Simon A, Ijspeert AJ. Walking with Salamanders: From Molecules to Biorobotics. Trends Neurosci 2020; 43:916-930. [PMID: 33010947 DOI: 10.1016/j.tins.2020.08.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/12/2020] [Accepted: 08/27/2020] [Indexed: 12/13/2022]
Abstract
How do four-legged animals adapt their locomotion to the environment? How do central and peripheral mechanisms interact within the spinal cord to produce adaptive locomotion and how is locomotion recovered when spinal circuits are perturbed? Salamanders are the only tetrapods that regenerate voluntary locomotion after full spinal transection. Given their evolutionary position, they provide a unique opportunity to bridge discoveries made in fish and mammalian models. Genetic dissection of salamander neural circuits is becoming feasible with new methods for precise manipulation, elimination, and visualisation of cells. These approaches can be combined with classical tools in neuroscience and with modelling and a robotic environment. We propose that salamanders provide a blueprint of the function, evolution, and regeneration of tetrapod locomotor circuits.
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Affiliation(s)
- Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada; Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada.
| | - András Simon
- Karolinska Institute, Department of Cell and Molecular Biology, Biomedicum, Solnavägen 9, 17163 Stockholm, Sweden
| | - Auke Jan Ijspeert
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
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46
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Clark EA, Rutlin M, Capano LS, Aviles S, Saadon JR, Taneja P, Zhang Q, Bullis JB, Lauer T, Myers E, Schulmann A, Forrest D, Nelson SB. Cortical RORβ is required for layer 4 transcriptional identity and barrel integrity. eLife 2020; 9:e52370. [PMID: 32851975 PMCID: PMC7492084 DOI: 10.7554/elife.52370] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 08/26/2020] [Indexed: 02/01/2023] Open
Abstract
Retinoic acid-related orphan receptor beta (RORβ) is a transcription factor (TF) and marker of layer 4 (L4) neurons, which are distinctive both in transcriptional identity and the ability to form aggregates such as barrels in rodent somatosensory cortex. However, the relationship between transcriptional identity and L4 cytoarchitecture is largely unknown. We find RORβ is required in the cortex for L4 aggregation into barrels and thalamocortical afferent (TCA) segregation. Interestingly, barrel organization also degrades with age in wildtype mice. Loss of RORβ delays excitatory input and disrupts gene expression and chromatin accessibility, with down-regulation of L4 and up-regulation of L5 genes, suggesting a disruption in cellular specification. Expression and binding site accessibility change for many other TFs, including closure of neurodevelopmental TF binding sites and increased expression and binding capacity of activity-regulated TFs. Lastly, a putative target of RORβ, Thsd7a, is down-regulated without RORβ, and Thsd7a knock-out alone disrupts TCA organization in adult barrels.
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MESH Headings
- Animals
- Antigens, Surface/chemistry
- Antigens, Surface/genetics
- Antigens, Surface/metabolism
- Female
- Male
- Membrane Proteins/chemistry
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Knockout
- Neurons/chemistry
- Neurons/cytology
- Neurons/metabolism
- Nuclear Receptor Subfamily 1, Group F, Member 2/chemistry
- Nuclear Receptor Subfamily 1, Group F, Member 2/genetics
- Nuclear Receptor Subfamily 1, Group F, Member 2/metabolism
- Somatosensory Cortex/chemistry
- Somatosensory Cortex/cytology
- Somatosensory Cortex/metabolism
- Somatosensory Cortex/physiology
- Thalamus/chemistry
- Thalamus/metabolism
- Transcription Factors/chemistry
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcriptome/genetics
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Affiliation(s)
- Erin A Clark
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Michael Rutlin
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Lucia S Capano
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Samuel Aviles
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Jordan R Saadon
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Praveen Taneja
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Qiyu Zhang
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - James B Bullis
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Timothy Lauer
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Emma Myers
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | | | - Douglas Forrest
- Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, NIDDKBethesdaUnited States
| | - Sacha B Nelson
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
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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: 5.3] [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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Caron G, Bilchak JN, Côté MP. Direct evidence for decreased presynaptic inhibition evoked by PBSt group I muscle afferents after chronic SCI and recovery with step-training in rats. J Physiol 2020; 598:4621-4642. [PMID: 32721039 DOI: 10.1113/jp280070] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/27/2020] [Indexed: 01/11/2023] Open
Abstract
KEY POINTS Presynaptic inhibition is modulated by supraspinal centres and primary afferents in order to filter sensory information, adjust spinal reflex excitability, and ensure smooth movement. After spinal cord injury (SCI), the supraspinal control of primary afferent depolarization (PAD) interneurons is disengaged, suggesting an increased role for sensory afferents. While increased H-reflex excitability in spastic individuals indicates a possible decrease in presynaptic inhibition, it remains unclear whether a decrease in sensory-evoked PAD contributes to this effect. We investigated whether the PAD evoked by hindlimb afferents contributes to the change in presynaptic inhibition of the H-reflex in a decerebrated rat preparation. We found that chronic SCI decreases presynaptic inhibition of the plantar H-reflex through a reduction in PAD evoked by posterior biceps-semitendinosus (PBSt) muscle group I afferents. We further found that step-training restored presynaptic inhibition of the plantar H-reflex evoked by PBSt, suggesting the presence of activity-dependent plasticity of PAD pathways activated by flexor muscle group I afferents. ABSTRACT Spinal cord injury (SCI) results in the disruption of supraspinal control of spinal networks and an increase in the relative influence of afferent feedback to sublesional neural networks, both of which contribute to enhancing spinal reflex excitability. Hyperreflexia occurs in ∼75% of individuals with a chronic SCI and critically hinders functional recovery and quality of life. It is suggested that it results from an increase in motoneuronal excitability and a decrease in presynaptic and postsynaptic inhibitory mechanisms. In contrast, locomotor training decreases hyperreflexia by restoring presynaptic inhibition. Primary afferent depolarization (PAD) is a powerful presynaptic inhibitory mechanism that selectively gates primary afferent transmission to spinal neurons to adjust reflex excitability and ensure smooth movement. However, the effect of chronic SCI and step-training on the reorganization of presynaptic inhibition evoked by hindlimb afferents, and the contribution of PAD has never been demonstrated. The objective of this study is to directly measure changes in presynaptic inhibition through dorsal root potentials (DRPs) and its association with plantar H-reflex inhibition. We provide direct evidence that H-reflex hyperexcitability is associated with a decrease in transmission of PAD pathways activated by posterior biceps-semitendinosus (PBSt) afferents after chronic SCI. More precisely, we illustrate that the pattern of inhibition evoked by PBSt group I muscle afferents onto both L4-DRPs and plantar H-reflexes evoked by the distal tibial nerve is impaired after chronic SCI. These changes are not observed in step-trained animals, suggesting a role for activity-dependent plasticity to regulate PAD pathways activated by flexor muscle group I afferents.
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Affiliation(s)
- Guillaume Caron
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19129
| | - Jadwiga N Bilchak
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19129
| | - Marie-Pascale Côté
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University, Philadelphia, PA, 19129
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Peirs C, Dallel R, Todd AJ. Recent advances in our understanding of the organization of dorsal horn neuron populations and their contribution to cutaneous mechanical allodynia. J Neural Transm (Vienna) 2020; 127:505-525. [PMID: 32239353 PMCID: PMC7148279 DOI: 10.1007/s00702-020-02159-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/10/2020] [Indexed: 02/07/2023]
Abstract
The dorsal horns of the spinal cord and the trigeminal nuclei in the brainstem contain neuron populations that are critical to process sensory information. Neurons in these areas are highly heterogeneous in their morphology, molecular phenotype and intrinsic properties, making it difficult to identify functionally distinct cell populations, and to determine how these are engaged in pathophysiological conditions. There is a growing consensus concerning the classification of neuron populations, based on transcriptomic and transductomic analyses of the dorsal horn. These approaches have led to the discovery of several molecularly defined cell types that have been implicated in cutaneous mechanical allodynia, a highly prevalent and difficult-to-treat symptom of chronic pain, in which touch becomes painful. The main objective of this review is to provide a contemporary view of dorsal horn neuronal populations, and describe recent advances in our understanding of on how they participate in cutaneous mechanical allodynia.
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Affiliation(s)
- Cedric Peirs
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, Clermont-Ferrand, F-63000, France.
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Radhouane Dallel
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, Clermont-Ferrand, F-63000, France
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
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Genome-wide association study: Understanding the genetic basis of the gait type in Brazilian Mangalarga Marchador horses, a preliminary study. Livest Sci 2020. [DOI: 10.1016/j.livsci.2019.103867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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