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Rault N, Bergmans T, Delfstra N, Kleijnen BJ, Zeldenrust F, Celikel T. Where Top-Down Meets Bottom-Up: Cell-Type Specific Connectivity Map of the Whisker System. Neuroinformatics 2024:10.1007/s12021-024-09658-6. [PMID: 38767789 DOI: 10.1007/s12021-024-09658-6] [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] [Accepted: 03/07/2024] [Indexed: 05/22/2024]
Abstract
Sensorimotor computation integrates bottom-up world state information with top-down knowledge and task goals to form action plans. In the rodent whisker system, a prime model of active sensing, evidence shows neuromodulatory neurotransmitters shape whisker control, affecting whisking frequency and amplitude. Since neuromodulatory neurotransmitters are mostly released from subcortical nuclei and have long-range projections that reach the rest of the central nervous system, mapping the circuits of top-down neuromodulatory control of sensorimotor nuclei will help to systematically address the mechanisms of active sensing. Therefore, we developed a neuroinformatic target discovery pipeline to mine the Allen Institute's Mouse Brain Connectivity Atlas. Using network connectivity analysis, we identified new putative connections along the whisker system and anatomically confirmed the existence of 42 previously unknown monosynaptic connections. Using this data, we updated the sensorimotor connectivity map of the mouse whisker system and developed the first cell-type-specific map of the network. The map includes 157 projections across 18 principal nuclei of the whisker system and neuromodulatory neurotransmitter-releasing. Performing a graph network analysis of this connectome, we identified cell-type specific hubs, sources, and sinks, provided anatomical evidence for monosynaptic inhibitory projections into all stages of the ascending pathway, and showed that neuromodulatory projections improve network-wide connectivity. These results argue that beyond the modulatory chemical contributions to information processing and transfer in the whisker system, the circuit connectivity features of the neuromodulatory networks position them as nodes of sensory and motor integration.
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Affiliation(s)
- Nicolas Rault
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.
| | - Tido Bergmans
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Natasja Delfstra
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | | | - Fleur Zeldenrust
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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Zhao B, Zhang H, Liu Y, Zu G, Zhang Y, Hu J, Liu S, You L. Forebrain excitatory neuron-specific loss of Brpf1 attenuates excitatory synaptic transmission and impairs spatial and fear memory. Neural Regen Res 2024; 19:1133-1141. [PMID: 37862219 PMCID: PMC10749587 DOI: 10.4103/1673-5374.385307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/10/2023] [Accepted: 07/19/2023] [Indexed: 10/22/2023] Open
Abstract
Bromodomain and plant homeodomain (PHD) finger containing protein 1 (Brpf1) is an activator and scaffold protein of a multiunit complex that includes other components involving lysine acetyltransferase (KAT) 6A/6B/7. Brpf1, KAT6A, and KAT6B mutations were identified as the causal genes of neurodevelopmental disorders leading to intellectual disability. Our previous work revealed strong and specific expression of Brpf1 in both the postnatal and adult forebrain, especially the hippocampus, which has essential roles in learning and memory. Here, we hypothesized that Brpf1 plays critical roles in the function of forebrain excitatory neurons, and that its deficiency leads to learning and memory deficits. To test this, we knocked out Brpf1 in forebrain excitatory neurons using CaMKIIa-Cre. We found that Brpf1 deficiency reduced the frequency of miniature excitatory postsynaptic currents and downregulated the expression of genes Pcdhgb1, Slc16a7, Robo3, and Rho, which are related to neural development, synapse function, and memory, thereby damaging spatial and fear memory in mice. These findings help explain the mechanisms of intellectual impairment in patients with BRPF1 mutation.
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Affiliation(s)
- Baicheng Zhao
- Department of Human Anatomy & Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Hang Zhang
- Department of Human Anatomy & Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Ying Liu
- Department of Human Anatomy & Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Gaoyu Zu
- Department of Human Anatomy & Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yuxiao Zhang
- Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Affiliated Mental Health Center (ECNU), School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
- Shanghai Changning Mental Health Center, Shanghai, China
- NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai, Shanghai, China
| | - Jiayi Hu
- Department of Human Anatomy & Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Shuai Liu
- Shanghai Key Laboratory of Brain Functional Genomics (Ministry of Education), Affiliated Mental Health Center (ECNU), School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
- Shanghai Changning Mental Health Center, Shanghai, China
- NYU-ECNU Institute of Brain and Cognitive Science at NYU Shanghai, Shanghai, China
| | - Linya You
- Department of Human Anatomy & Histoembryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, China
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Akter M, Cui H, Hosain MA, Liu J, Duan Y, Ding B. RANBP17 Overexpression Restores Nucleocytoplasmic Transport and Ameliorates Neurodevelopment in Induced DYT1 Dystonia Motor Neurons. J Neurosci 2024; 44:e1728232024. [PMID: 38438257 PMCID: PMC11007476 DOI: 10.1523/jneurosci.1728-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/06/2024] Open
Abstract
DYT1 dystonia is a debilitating neurological movement disorder, and it represents the most frequent and severe form of hereditary primary dystonia. There is currently no cure for this disease due to its unclear pathogenesis. In our previous study utilizing patient-specific motor neurons (MNs), we identified distinct cellular deficits associated with the disease, including a deformed nucleus, disrupted neurodevelopment, and compromised nucleocytoplasmic transport (NCT) functions. However, the precise molecular mechanisms underlying these cellular impairments have remained elusive. In this study, we revealed the genome-wide changes in gene expression in DYT1 MNs through transcriptomic analysis. We found that those dysregulated genes are intricately involved in neurodevelopment and various biological processes. Interestingly, we identified that the expression level of RANBP17, a RAN-binding protein crucial for NCT regulation, exhibited a significant reduction in DYT1 MNs. By manipulating RANBP17 expression, we further demonstrated that RANBP17 plays an important role in facilitating the nuclear transport of both protein and transcript cargos in induced human neurons. Excitingly, the overexpression of RANBP17 emerged as a substantial mitigating factor, effectively restoring impaired NCT activity and rescuing neurodevelopmental deficits observed in DYT1 MNs. These findings shed light on the intricate molecular underpinnings of impaired NCT in DYT1 neurons and provide novel insights into the pathophysiology of DYT1 dystonia, potentially leading to the development of innovative treatment strategies.
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Affiliation(s)
- Masuma Akter
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, Louisiana 71130-3932
| | - Haochen Cui
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, Louisiana 71130-3932
| | - Md Abir Hosain
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, Louisiana 71130-3932
| | - Jinmei Liu
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, Louisiana 71130-3932
| | - Yuntian Duan
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, Louisiana 71130-3932
| | - Baojin Ding
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, Louisiana 71130-3932
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Kebschull JM, Casoni F, Consalez GG, Goldowitz D, Hawkes R, Ruigrok TJH, Schilling K, Wingate R, Wu J, Yeung J, Uusisaari MY. Cerebellum Lecture: the Cerebellar Nuclei-Core of the Cerebellum. CEREBELLUM (LONDON, ENGLAND) 2024; 23:620-677. [PMID: 36781689 PMCID: PMC10951048 DOI: 10.1007/s12311-022-01506-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/10/2022] [Indexed: 02/15/2023]
Abstract
The cerebellum is a key player in many brain functions and a major topic of neuroscience research. However, the cerebellar nuclei (CN), the main output structures of the cerebellum, are often overlooked. This neglect is because research on the cerebellum typically focuses on the cortex and tends to treat the CN as relatively simple output nuclei conveying an inverted signal from the cerebellar cortex to the rest of the brain. In this review, by adopting a nucleocentric perspective we aim to rectify this impression. First, we describe CN anatomy and modularity and comprehensively integrate CN architecture with its highly organized but complex afferent and efferent connectivity. This is followed by a novel classification of the specific neuronal classes the CN comprise and speculate on the implications of CN structure and physiology for our understanding of adult cerebellar function. Based on this thorough review of the adult literature we provide a comprehensive overview of CN embryonic development and, by comparing cerebellar structures in various chordate clades, propose an interpretation of CN evolution. Despite their critical importance in cerebellar function, from a clinical perspective intriguingly few, if any, neurological disorders appear to primarily affect the CN. To highlight this curious anomaly, and encourage future nucleocentric interpretations, we build on our review to provide a brief overview of the various syndromes in which the CN are currently implicated. Finally, we summarize the specific perspectives that a nucleocentric view of the cerebellum brings, move major outstanding issues in CN biology to the limelight, and provide a roadmap to the key questions that need to be answered in order to create a comprehensive integrated model of CN structure, function, development, and evolution.
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Affiliation(s)
- Justus M Kebschull
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21205, USA.
| | - Filippo Casoni
- Division of Neuroscience, San Raffaele Scientific Institute, and San Raffaele University, Milan, Italy
| | - G Giacomo Consalez
- Division of Neuroscience, San Raffaele Scientific Institute, and San Raffaele University, Milan, Italy
| | - Daniel Goldowitz
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Richard Hawkes
- Department of Cell Biology & Anatomy and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Tom J H Ruigrok
- Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
| | - Karl Schilling
- Department of Anatomy, Anatomy & Cell Biology, Rheinische Friedrich-Wilhelms-Universität, 53115, Bonn, Federal Republic of Germany
| | - Richard Wingate
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Joshua Wu
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Joanna Yeung
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Marylka Yoe Uusisaari
- Neuronal Rhythms in Movement Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-Son, Kunigami-Gun, Okinawa, 904-0495, Japan.
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5
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Hand AR, Abramson CXG, Dressler KA. Tlx1 regulates acinar and duct development in mouse salivary glands. J Anat 2024; 244:343-357. [PMID: 37837237 PMCID: PMC10780161 DOI: 10.1111/joa.13964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023] Open
Abstract
Tlx1 encodes a transcription factor expressed in several craniofacial structures of developing mice. The role of Tlx1 in salivary gland development was examined using morphological and immunohistochemical analyses of Tlx1 null mice. Tlx1 is expressed in submandibular and sublingual glands but not parotid glands of neonatal and adult male and female C57Bl/6J (Tlx1+/+ ) mice. TLX1 protein was localized to the nuclei of terminal tubule cells, developing duct cells and mesenchymal cells in neonatal submandibular and sublingual glands, and to nuclei of duct cells and connective tissue cells in adult glands. Occasionally, TLX1 was observed in nuclei of epithelial cells in or adjacent to the acini. Submandibular glands were smaller and sublingual glands were larger in size in mutant mice (Tlx1-/- ) compared to wild-type mice. Differentiation of terminal tubule and proacinar cells of neonatal Tlx1-/- submandibular glands was abnormal; expression of their characteristic products, submandibular gland protein C and parotid secretory protein, respectively, was reduced. At 3 weeks postnatally, terminal tubule cells at the acinar-intercalated duct junction were poorly developed or absent in Tlx1-/- mice. Granular convoluted ducts in adult mutant mice were decreased, and epidermal growth factor and nerve growth factor expression were reduced. Along with normal acinar cell proteins, adult acinar cells of Tlx1-/- mice continued to express neonatal proteins and expressed parotid proteins not normally present in submandibular glands. Sublingual gland mucous acinar and serous demilune cell differentiation were altered. Tlx1 is necessary for proper differentiation of submandibular and sublingual gland acinar cells, and granular convoluted ducts. The mechanism(s) underlying Tlx1 regulation of salivary gland development and differentiation remains unknown.
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Affiliation(s)
- Arthur R Hand
- Department of Craniofacial Sciences, University of Connecticut School of Dental Medicine, Farmington, Connecticut, USA
| | - Cailyn X G Abramson
- Department of Craniofacial Sciences, University of Connecticut School of Dental Medicine, Farmington, Connecticut, USA
| | - Keith A Dressler
- Department of Craniofacial Sciences, University of Connecticut School of Dental Medicine, Farmington, Connecticut, USA
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Bryce-Smith S, Brown AL, Mehta PR, Mattedi F, Mikheenko A, Barattucci S, Zanovello M, Dattilo D, Yome M, Hill SE, Qi YA, Wilkins OG, Sun K, Ryadnov E, Wan Y, Vargas JNS, Birsa N, Raj T, Humphrey J, Keuss M, Ward M, Secrier M, Fratta P. TDP-43 loss induces extensive cryptic polyadenylation in ALS/FTD. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.22.576625. [PMID: 38313254 PMCID: PMC10836071 DOI: 10.1101/2024.01.22.576625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Nuclear depletion and cytoplasmic aggregation of the RNA-binding protein TDP-43 is the hallmark of ALS, occurring in over 97% of cases. A key consequence of TDP-43 nuclear loss is the de-repression of cryptic exons. Whilst TDP-43 regulated cryptic splicing is increasingly well catalogued, cryptic alternative polyadenylation (APA) events, which define the 3' end of last exons, have been largely overlooked, especially when not associated with novel upstream splice junctions. We developed a novel bioinformatic approach to reliably identify distinct APA event types: alternative last exons (ALE), 3'UTR extensions (3'Ext) and intronic polyadenylation (IPA) events. We identified novel neuronal cryptic APA sites induced by TDP-43 loss of function by systematically applying our pipeline to a compendium of publicly available and in house datasets. We find that TDP-43 binding sites and target motifs are enriched at these cryptic events and that TDP-43 can have both repressive and enhancing action on APA. Importantly, all categories of cryptic APA can also be identified in ALS and FTD post mortem brain regions with TDP-43 proteinopathy underlining their potential disease relevance. RNA-seq and Ribo-seq analyses indicate that distinct cryptic APA categories have different downstream effects on transcript and translation. Intriguingly, cryptic 3'Exts occur in multiple transcription factors, such as ELK1, SIX3, and TLX1, and lead to an increase in wild-type protein levels and function. Finally, we show that an increase in RNA stability leading to a higher cytoplasmic localisation underlies these observations. In summary, we demonstrate that TDP-43 nuclear depletion induces a novel category of cryptic RNA processing events and we expand the palette of TDP-43 loss consequences by showing this can also lead to an increase in normal protein translation.
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Affiliation(s)
- Sam Bryce-Smith
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Anna-Leigh Brown
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Puja R. Mehta
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Francesca Mattedi
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Alla Mikheenko
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Simone Barattucci
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Matteo Zanovello
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Dario Dattilo
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Matthew Yome
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Sarah E. Hill
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Yue A. Qi
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Oscar G. Wilkins
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
- The Francis Crick Institute, London, UK
| | - Kai Sun
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Eugeni Ryadnov
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Yixuan Wan
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | | | - Jose Norberto S. Vargas
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Nicol Birsa
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Towfique Raj
- Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Genetics and Genomic Sciences & Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jack Humphrey
- Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Genetics and Genomic Sciences & Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Estelle and Daniel Maggin Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Matthew Keuss
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Michael Ward
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Maria Secrier
- UCL Genetics Institute, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Pietro Fratta
- UCL Queen Square Motor Neuron Disease Centre, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
- The Francis Crick Institute, London, UK
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England SJ, Rusnock AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular analyses of zebrafish V0v spinal interneurons and identification of transcriptional regulators downstream of Evx1 and Evx2 in these cells. Neural Dev 2023; 18:8. [PMID: 38017520 PMCID: PMC10683209 DOI: 10.1186/s13064-023-00176-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/12/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. METHODS To identify candidate members of V0v gene regulatory networks, we FAC-sorted wild-type and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. RESULTS Our data reveal two molecularly distinct subtypes of zebrafish V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuron expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. CONCLUSIONS This study identifies two molecularly distinct subsets of zebrafish V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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Affiliation(s)
| | | | - Amra Mujcic
- Biology Department, Syracuse University, Syracuse, NY, USA
| | | | - Sarah de Jager
- Physiology, Development and Neuroscience Department, Cambridge University, Cambridge, UK
| | | | - José L Juárez-Morales
- Biology Department, Syracuse University, Syracuse, NY, USA
- Programa de IxM-CONAHCYT, Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), La Paz, Baja California Sur, México
| | | | - Ginny Grieb
- Biology Department, Syracuse University, Syracuse, NY, USA
| | - Santanu Banerjee
- Biological Sciences Department, SUNY-Cortland, Cortland, NY, USA
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8
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England SJ, Woodard AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular Analyses of V0v Spinal Interneurons and Identification of Transcriptional Regulators Downstream of Evx1 and Evx2 in these Cells. RESEARCH SQUARE 2023:rs.3.rs-3290462. [PMID: 37693471 PMCID: PMC10491344 DOI: 10.21203/rs.3.rs-3290462/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Background V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. Methods To identify candidate members of V0v gene regulatory networks, we FAC-sorted WT and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. Results Our data reveal two molecularly distinct subtypes of V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuronal expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. Conclusions This study identifies two molecularly distinct subsets of V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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9
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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: 2] [Impact Index Per Article: 2.0] [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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10
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Chen J, Huang L, Yang Y, Xu W, Qin Q, Qin R, Liang X, Lai X, Huang X, Xie M, Chen L. Somatic Cell Reprogramming for Nervous System Diseases: Techniques, Mechanisms, Potential Applications, and Challenges. Brain Sci 2023; 13:brainsci13030524. [PMID: 36979334 PMCID: PMC10046178 DOI: 10.3390/brainsci13030524] [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: 02/04/2023] [Revised: 03/14/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Nervous system diseases present significant challenges to the neuroscience community due to ethical and practical constraints that limit access to appropriate research materials. Somatic cell reprogramming has been proposed as a novel way to obtain neurons. Various emerging techniques have been used to reprogram mature and differentiated cells into neurons. This review provides an overview of somatic cell reprogramming for neurological research and therapy, focusing on neural reprogramming and generating different neural cell types. We examine the mechanisms involved in reprogramming and the challenges that arise. We herein summarize cell reprogramming strategies to generate neurons, including transcription factors, small molecules, and microRNAs, with a focus on different types of cells.. While reprogramming somatic cells into neurons holds the potential for understanding neurological diseases and developing therapeutic applications, its limitations and risks must be carefully considered. Here, we highlight the potential benefits of somatic cell reprogramming for neurological disease research and therapy. This review contributes to the field by providing a comprehensive overview of the various techniques used to generate neurons by cellular reprogramming and discussing their potential applications.
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Affiliation(s)
- Jiafeng Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Lijuan Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Yue Yang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Wei Xu
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Qingchun Qin
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Rongxing Qin
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Xiaojun Liang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Xinyu Lai
- Key Laboratory of Longevity and Aging-Related Diseases of Chinese Ministry of Education, Nanning 530021, China
| | - Xiaoying Huang
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Minshan Xie
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Li Chen
- Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
- Key Laboratory of Longevity and Aging-Related Diseases of Chinese Ministry of Education, Nanning 530021, China
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11
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Haws W, England S, Grieb G, Susana G, Hernandez S, Mirer H, Lewis K. Analyses of binding partners and functional domains for the developmentally essential protein Hmx3a/HMX3. Sci Rep 2023; 13:1151. [PMID: 36670152 PMCID: PMC9859826 DOI: 10.1038/s41598-023-27878-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023] Open
Abstract
HMX3 is a homeodomain protein with essential roles in CNS and ear development. Homeodomains are DNA-binding domains and hence homeodomain-containing proteins are usually assumed to be transcription factors. However, intriguingly, our recent data suggest that zebrafish Hmx3a may not require its homeodomain to function, raising the important question of what molecular interactions mediate its effects. To investigate this, we performed a yeast two-hybrid screen and identified 539 potential binding partners of mouse HMX3. Using co-immunoprecipitation, we tested whether a prioritized subset of these interactions are conserved in zebrafish and found that Tle3b, Azin1b, Prmt2, Hmgb1a, and Hmgn3 bind Hmx3a. Next, we tested whether these proteins bind the products of four distinct hmx3a mutant alleles that all lack the homeodomain. Embryos homozygous for two of these alleles develop abnormally and die, whereas zebrafish homozygous for the other two alleles are viable. We found that all four mutations abrogate binding to Prmt2 and Tle3b, whereas Azin1b binding was preserved in all cases. Interestingly, Hmgb1a and Hmgn3 had more affinity for products of the viable mutant alleles. These data shed light on how HMX3/Hmx3a might function at a molecular level and identify new targets for future study in these vital developmental processes.
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Affiliation(s)
- William Haws
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Samantha England
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Ginny Grieb
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Gabriela Susana
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Sophie Hernandez
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Hunter Mirer
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Katharine Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
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12
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Grpr expression defines a population of superficial dorsal horn vertical cells that have a role in both itch and pain. Pain 2023; 164:149-170. [PMID: 35543635 PMCID: PMC9756441 DOI: 10.1097/j.pain.0000000000002677] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/06/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Neurons in the superficial dorsal horn that express the gastrin-releasing peptide receptor (GRPR) are strongly implicated in spinal itch pathways. However, a recent study reported that many of these correspond to vertical cells, a population of interneurons that are believed to transmit nociceptive information. In this study, we have used a GRPR CreERT2 mouse line to identify and target cells that possess Grpr mRNA. We find that the GRPR cells are highly concentrated in lamina I and the outer part of lamina II, that they are all glutamatergic, and that they account for ∼15% of the excitatory neurons in the superficial dorsal horn. We had previously identified 6 neurochemically distinct excitatory interneuron populations in this region based on neuropeptide expression and the GRPR cells are largely separate from these, although they show some overlap with cells that express substance P. Anatomical analysis revealed that the GRPR neurons are indeed vertical cells, and that their axons target each other, as well as arborising in regions that contain projection neurons: lamina I, the lateral spinal nucleus, and the lateral part of lamina V. Surprisingly, given the proposed role of GRPR cells in itch, we found that most of the cells received monosynaptic input from Trpv1-expressing (nociceptive) afferents, that the majority responded to noxious and pruritic stimuli, and that chemogenetically activating them resulted in pain-related and itch-related behaviours. Together, these findings suggest that the GRPR cells are involved in spinal cord circuits that underlie both pain and itch.
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13
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Xia Y, Cui K, Alonso A, Lowenstein ED, Hernandez-Miranda LR. Transcription factors regulating the specification of brainstem respiratory neurons. Front Mol Neurosci 2022; 15:1072475. [PMID: 36523603 PMCID: PMC9745097 DOI: 10.3389/fnmol.2022.1072475] [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: 10/17/2022] [Accepted: 11/14/2022] [Indexed: 11/12/2023] Open
Abstract
Breathing (or respiration) is an unconscious and complex motor behavior which neuronal drive emerges from the brainstem. In simplistic terms, respiratory motor activity comprises two phases, inspiration (uptake of oxygen, O2) and expiration (release of carbon dioxide, CO2). Breathing is not rigid, but instead highly adaptable to external and internal physiological demands of the organism. The neurons that generate, monitor, and adjust breathing patterns locate to two major brainstem structures, the pons and medulla oblongata. Extensive research over the last three decades has begun to identify the developmental origins of most brainstem neurons that control different aspects of breathing. This research has also elucidated the transcriptional control that secures the specification of brainstem respiratory neurons. In this review, we aim to summarize our current knowledge on the transcriptional regulation that operates during the specification of respiratory neurons, and we will highlight the cell lineages that contribute to the central respiratory circuit. Lastly, we will discuss on genetic disturbances altering transcription factor regulation and their impact in hypoventilation disorders in humans.
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Affiliation(s)
- Yiling Xia
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ke Cui
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Antonia Alonso
- Functional Genoarchitecture and Neurobiology Groups, Biomedical Research Institute of Murcia (IMIB-Arrixaca), Murcia, Spain
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain
| | - Elijah D. Lowenstein
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Luis R. Hernandez-Miranda
- The Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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14
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Shively SB, Edwards NA, MacDonald TJ, Johnson KR, Diaz-Rodriguez NM, Merrill MJ, Vortmeyer AO. Developmentally Arrested Basket/Stellate Cells in Postnatal Human Brain as Potential Tumor Cells of Origin for Cerebellar Hemangioblastoma in von Hippel-Lindau Patients. J Neuropathol Exp Neurol 2022; 81:885-899. [PMID: 35980299 PMCID: PMC9803908 DOI: 10.1093/jnen/nlac073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary cancer disorder caused by a germline mutation in the VHL tumor suppressor gene. Loss of the wild-type allele results in VHL deficiency and the potential formation of cerebellar hemangioblastomas, which resemble embryonic hemangioblast proliferation and differentiation processes. Multiple, microscopic, VHL-deficient precursors, termed developmentally arrested structural elements (DASEs), consistently involve the cerebellar molecular layer in VHL patients, indicating the tumor site of origin. Unlike hemangioblastomas, however, cerebellar DASEs do not express brachyury, a mesodermal marker for hemangioblasts. In this study, neuronal progenitors occupying the molecular layer were investigated as tumor cells of origin. By immunohistochemistry, cerebellar DASEs and hemangioblastomas lacked immunoreactivity with antibody ZIC1 (Zic family member 1), a granule cell progenitor marker with concordance from oligonucleotide RNA expression array analyses. Rather, cerebellar DASEs and hemangioblastomas were immunoreactive with antibody PAX2 (paired box 2), a marker of basket/stellate cell progenitors. VHL cerebellar cortices also revealed PAX2-positive cells in Purkinje and molecular layers, resembling the histological and molecular development of basket/stellate cells in postnatal non-VHL mouse and human cerebella. These data suggest that VHL deficiency can result in the developmental arrest of basket/stellate cells in the human cerebellum and that these PAX2-positive, initiated cells await another insult or signal to form DASEs and eventually, tumors.
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Affiliation(s)
- Sharon Baughman Shively
- From the Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA,Department of Molecular Medicine, Institute for Biomedical Sciences, The George Washington University, Washington, District of Columbia, USA
| | - Nancy A Edwards
- From the Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Kory R Johnson
- Bioinformatics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | | | | | - Alexander O Vortmeyer
- Send correspondence to: Alexander O. Vortmeyer, MD, PhD, Division of Neuropathology, Department of Pathology and Laboratory Medicine, Indiana University-Purdue University Indianapolis, 350 W. 11th Street, Suite 4034, Indianapolis, IN 46202, USA; E-mail:
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15
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Gupta S, Kawaguchi R, Heinrichs E, Gallardo S, Castellanos S, Mandric I, Novitch BG, Butler SJ. In vitro atlas of dorsal spinal interneurons reveals Wnt signaling as a critical regulator of progenitor expansion. Cell Rep 2022; 40:111119. [PMID: 35858555 PMCID: PMC9414195 DOI: 10.1016/j.celrep.2022.111119] [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: 11/08/2021] [Revised: 04/12/2022] [Accepted: 06/28/2022] [Indexed: 11/03/2022] Open
Abstract
Restoring sensation after injury or disease requires a reproducible method for generating large quantities of bona fide somatosensory interneurons. Toward this goal, we assess the mechanisms by which dorsal spinal interneurons (dIs; dI1-dI6) can be derived from mouse embryonic stem cells (mESCs). Using two developmentally relevant growth factors, retinoic acid (RA) and bone morphogenetic protein (BMP) 4, we recapitulate the complete in vivo program of dI differentiation through a neuromesodermal intermediate. Transcriptional profiling reveals that mESC-derived dIs strikingly resemble endogenous dIs, with the correct molecular and functional signatures. We further demonstrate that RA specifies dI4-dI6 fates through a default multipotential state, while the addition of BMP4 induces dI1-dI3 fates and activates Wnt signaling to enhance progenitor proliferation. Constitutively activating Wnt signaling permits the dramatic expansion of neural progenitor cultures. These cultures retain the capacity to differentiate into diverse populations of dIs, thereby providing a method of increasing neuronal yield.
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Affiliation(s)
- Sandeep Gupta
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Riki Kawaguchi
- Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Eric Heinrichs
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Genetics and Genomics Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Salena Gallardo
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Stephanie Castellanos
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA; CIRM Bridges to Research Program, California State University, Northridge, Los Angeles, CA, USA
| | - Igor Mandric
- Department of Computer Science, Samueli School of Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Bennett G Novitch
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA; Intellectual & Developmental Disabilities Research Center, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Samantha J Butler
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA; Intellectual & Developmental Disabilities Research Center, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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16
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Neurotransmitter phenotype switching by spinal excitatory interneurons regulates locomotor recovery after spinal cord injury. Nat Neurosci 2022; 25:617-629. [PMID: 35524138 PMCID: PMC9076533 DOI: 10.1038/s41593-022-01067-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 03/29/2022] [Indexed: 11/08/2022]
Abstract
Severe spinal cord injury in adults leads to irreversible paralysis below the lesion. However, adult rodents that received a complete thoracic lesion just after birth demonstrate proficient hindlimb locomotion without input from the brain. How the spinal cord achieves such striking plasticity remains unknown. In this study, we found that adult spinal cord injury prompts neurotransmitter switching of spatially defined excitatory interneurons to an inhibitory phenotype, promoting inhibition at synapses contacting motor neurons. In contrast, neonatal spinal cord injury maintains the excitatory phenotype of glutamatergic interneurons and causes synaptic sprouting to facilitate excitation. Furthermore, genetic manipulation to mimic the inhibitory phenotype observed in excitatory interneurons after adult spinal cord injury abrogates autonomous locomotor functionality in neonatally injured mice. In comparison, attenuating this inhibitory phenotype improves locomotor capacity after adult injury. Together, these data demonstrate that neurotransmitter phenotype of defined excitatory interneurons steers locomotor recovery after spinal cord injury.
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17
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Yaghmaeian Salmani B, Balderson B, Bauer S, Ekman H, Starkenberg A, Perlmann T, Piper M, Bodén M, Thor S. Selective requirement for polycomb repressor complex 2 in the generation of specific hypothalamic neuronal subtypes. Development 2022; 149:274592. [PMID: 35245348 PMCID: PMC8959139 DOI: 10.1242/dev.200076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 01/18/2022] [Indexed: 11/20/2022]
Abstract
The hypothalamus displays staggering cellular diversity, chiefly established during embryogenesis by the interplay of several signalling pathways and a battery of transcription factors. However, the contribution of epigenetic cues to hypothalamus development remains unclear. We mutated the polycomb repressor complex 2 gene Eed in the developing mouse hypothalamus, which resulted in the loss of H3K27me3, a fundamental epigenetic repressor mark. This triggered ectopic expression of posteriorly expressed regulators (e.g. Hox homeotic genes), upregulation of cell cycle inhibitors and reduced proliferation. Surprisingly, despite these effects, single cell transcriptomic analysis revealed that most neuronal subtypes were still generated in Eed mutants. However, we observed an increase in glutamatergic/GABAergic double-positive cells, as well as loss/reduction of dopamine, hypocretin and Tac2-Pax6 neurons. These findings indicate that many aspects of the hypothalamic gene regulatory flow can proceed without the key H3K27me3 epigenetic repressor mark, but points to a unique sensitivity of particular neuronal subtypes to a disrupted epigenomic landscape. Summary: Polycomb repressor complex 2 inactivation results in selective effects on mouse hypothalamic development, increasing glutamatergic/GABA cells, while reducing dopamine, Hcrt and Tac2-Pax6 cells.
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Affiliation(s)
- Behzad Yaghmaeian Salmani
- Department of Clinical and Experimental Medicine, Linkoping University, SE-58185 Linkoping, Sweden
- Department of Cell and Molecular Biology, Karolinska Institute, SE-17177 Stockholm, Sweden
| | - Brad Balderson
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Susanne Bauer
- Department of Clinical and Experimental Medicine, Linkoping University, SE-58185 Linkoping, Sweden
| | - Helen Ekman
- Department of Clinical and Experimental Medicine, Linkoping University, SE-58185 Linkoping, Sweden
| | - Annika Starkenberg
- Department of Clinical and Experimental Medicine, Linkoping University, SE-58185 Linkoping, Sweden
| | - Thomas Perlmann
- Department of Cell and Molecular Biology, Karolinska Institute, SE-17177 Stockholm, Sweden
| | - Michael Piper
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Mikael Bodén
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Stefan Thor
- Department of Clinical and Experimental Medicine, Linkoping University, SE-58185 Linkoping, Sweden
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD 4072, Australia
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18
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Hirsch D, Kohl A, Wang Y, Sela-Donenfeld D. Axonal Projection Patterns of the Dorsal Interneuron Populations in the Embryonic Hindbrain. Front Neuroanat 2022; 15:793161. [PMID: 35002640 PMCID: PMC8738170 DOI: 10.3389/fnana.2021.793161] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Unraveling the inner workings of neural circuits entails understanding the cellular origin and axonal pathfinding of various neuronal groups during development. In the embryonic hindbrain, different subtypes of dorsal interneurons (dINs) evolve along the dorsal-ventral (DV) axis of rhombomeres and are imperative for the assembly of central brainstem circuits. dINs are divided into two classes, class A and class B, each containing four neuronal subgroups (dA1-4 and dB1-4) that are born in well-defined DV positions. While all interneurons belonging to class A express the transcription factor Olig3 and become excitatory, all class B interneurons express the transcription factor Lbx1 but are diverse in their excitatory or inhibitory fate. Moreover, within every class, each interneuron subtype displays its own specification genes and axonal projection patterns which are required to govern the stage-by-stage assembly of their connectivity toward their target sites. Remarkably, despite the similar genetic landmark of each dINs subgroup along the anterior-posterior (AP) axis of the hindbrain, genetic fate maps of some dA/dB neuronal subtypes uncovered their contribution to different nuclei centers in relation to their rhombomeric origin. Thus, DV and AP positional information has to be orchestrated in each dA/dB subpopulation to form distinct neuronal circuits in the hindbrain. Over the span of several decades, different axonal routes have been well-documented to dynamically emerge and grow throughout the hindbrain DV and AP positions. Yet, the genetic link between these distinct axonal bundles and their neuronal origin is not fully clear. In this study, we reviewed the available data regarding the association between the specification of early-born dorsal interneuron subpopulations in the hindbrain and their axonal circuitry development and fate, as well as the present existing knowledge on molecular effectors underlying the process of axonal growth.
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Affiliation(s)
- Dana Hirsch
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.,Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Ayelet Kohl
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuan Wang
- Department of Biomedical Sciences, Program in Neuroscience, College of Medicine, Florida State University, Tallahassee, FL, United States
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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19
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Abstract
Breathing (or respiration) is a complex motor behavior that originates in the brainstem. In minimalistic terms, breathing can be divided into two phases: inspiration (uptake of oxygen, O2) and expiration (release of carbon dioxide, CO2). The neurons that discharge in synchrony with these phases are arranged in three major groups along the brainstem: (i) pontine, (ii) dorsal medullary, and (iii) ventral medullary. These groups are formed by diverse neuron types that coalesce into heterogeneous nuclei or complexes, among which the preBötzinger complex in the ventral medullary group contains cells that generate the respiratory rhythm (Chapter 1). The respiratory rhythm is not rigid, but instead highly adaptable to the physic demands of the organism. In order to generate the appropriate respiratory rhythm, the preBötzinger complex receives direct and indirect chemosensory information from other brainstem respiratory nuclei (Chapter 2) and peripheral organs (Chapter 3). Even though breathing is a hard-wired unconscious behavior, it can be temporarily altered at will by other higher-order brain structures (Chapter 6), and by emotional states (Chapter 7). In this chapter, we focus on the development of brainstem respiratory groups and highlight the cell lineages that contribute to central and peripheral chemoreflexes.
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Affiliation(s)
- Eser Göksu Isik
- Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Luis R Hernandez-Miranda
- Brainstem Group, Institute for Cell Biology and Neurobiology, Charité Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
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20
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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: 96] [Impact Index Per Article: 32.0] [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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21
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Shen Y, Liu F, Duan J, Wang W, Yang H, Wang Z, Wang T, Kong Y, Ma B, Hao M, Zhao H, Liu H. Biomaterial Cues Regulated Differentiation of Neural Stem Cells into GABAergic Neurons through Ca 2+/c-Jun/TLX3 Signaling Promoted by Hydroxyapatite Nanorods. NANO LETTERS 2021; 21:7371-7378. [PMID: 34423634 DOI: 10.1021/acs.nanolett.1c02708] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Directed differentiation enables the production of a specific cell type by manipulating signals in development. However, there is a lack of effective means to accelerate the regeneration of neurons of particular subtypes for pathogenesis and clinical therapy. In this study, we find that hydroxyapatite (HAp) nanorods promote neural differentiation of neural stem cells due to their chemical compositions. Lysosome-mediated degradation of HAp nanorods elevates intracellular calcium concentrations and accelerates GABAergic neurogenesis. As a mechanism, the enhanced activity of a Ca2+ peak initiated by HAp nanorods leads to the activation of c-Jun and thus suppresses the expression of GABAergic/glutamatergic selection gene TLX3. We demonstrate the capability of HAp nanorods in promoting the differentiation into GABAergic neurons at both molecular and cellular function levels. Given that GABAergic neurons are responsible for various physiological and pathological processes, our findings open up enormous opportunities in efficient and precise stem cell therapy of neurodegenerative diseases.
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Affiliation(s)
- Yinan Shen
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Feng Liu
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Jiazhi Duan
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Wenhan Wang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Hongru Yang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Zizhao Wang
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Tailin Wang
- Key Laboratory of Processing and Testing Technology of Glass & Functional Ceramics of Shandong Province, School of Materials, Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250353, China
| | - Ying Kong
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Baojin Ma
- Department of Periodontology, School and Hospital of Stomatology, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, Shandong 250012, China
| | - Min Hao
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Hang Zhao
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Hong Liu
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
- Institute for Advanced Interdisciplinary Research (IAIR), University of Jinan, Jinan, Shandong 250022, China
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22
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Haimson B, Hadas Y, Bernat N, Kania A, Daley MA, Cinnamon Y, Lev-Tov A, Klar A. Spinal lumbar dI2 interneurons contribute to stability of bipedal stepping. eLife 2021; 10:62001. [PMID: 34396953 PMCID: PMC8448531 DOI: 10.7554/elife.62001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 08/11/2021] [Indexed: 11/13/2022] Open
Abstract
Peripheral and intraspinal feedback is required to shape and update the output of spinal networks that execute motor behavior. We report that lumbar dI2 spinal interneurons in chicks receive synaptic input from afferents and premotor neurons. These interneurons innervate contralateral premotor networks in the lumbar and brachial spinal cord, and their ascending projections innervate the cerebellum. These findings suggest that dI2 neurons function as interneurons in local lumbar circuits, are involved in lumbo-brachial coupling, and that part of them deliver peripheral and intraspinal feedback to the cerebellum. Silencing of dI2 neurons leads to destabilized stepping in P8 hatchlings, with occasional collapses, variable step profiles and a wide-base walking gait, suggesting that dI2 neurons may contribute to the stabilization of the bipedal gait.
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Affiliation(s)
- Baruch Haimson
- Department of Medical Neurobiology,, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel, jerusalem, Israel
| | - Yoav Hadas
- Department of Medical Neurobiology,, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel, Jerusalem, Israel
| | - Nimrod Bernat
- Department of Medical Neurobiology,, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel, jerusalem, Israel
| | - Artur Kania
- Anatomy and Cell Biology, Institut de recherches cliniques de Montréal (IRCM), Montreal, Canada
| | - Monica A Daley
- Ecology and Evolutionary Biology, University of California, Irvine, Irvine, United States
| | - Yuval Cinnamon
- Institute of Animal Science Poultry and Aquaculture Sci. Dept, Institute of Animal Science Poultry and Aquaculture Sci. Dept. Agricultural Research Organization, The Volcani Center, Israel, Rehovot, Israel
| | - Aharon Lev-Tov
- Department of Medical Neurobiology,, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, 91120, Israel, Jerisalem, Israel
| | - Avihu Klar
- Medical Neurobiology, Hebrew University, Jerusalem, Israel
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23
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Kurashina M, Wang J, Lin J, Lee KK, Johal A, Mizumoto K. Sustained expression of unc-4 homeobox gene and unc-37/Groucho in postmitotic neurons specifies the spatial organization of the cholinergic synapses in C. elegans. eLife 2021; 10:66011. [PMID: 34388088 PMCID: PMC8363302 DOI: 10.7554/elife.66011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 08/07/2021] [Indexed: 11/13/2022] Open
Abstract
Neuronal cell fate determinants establish the identities of neurons by controlling gene expression to regulate neuronal morphology and synaptic connectivity. However, it is not understood if neuronal cell fate determinants have postmitotic functions in synapse pattern formation. Here we identify a novel role for UNC-4 homeobox protein and its corepressor UNC-37/Groucho, in tiled synaptic patterning of the cholinergic motor neurons in Caenorhabditis elegans. We show that unc-4 is not required during neurogenesis but is required in the postmitotic neurons for proper synapse patterning. In contrast, unc-37 is required in both developing and postmitotic neurons. The synaptic tiling defects of unc-4 mutants are suppressed by bar-1/β-catenin mutation, which positively regulates the expression of ceh-12/HB9. Ectopic ceh-12 expression partly underlies the synaptic tiling defects of unc-4 and unc-37 mutants. Our results reveal a novel postmitotic role of neuronal cell fate determinants in synapse pattern formation through inhibiting the canonical Wnt signaling pathway.
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Affiliation(s)
- Mizuki Kurashina
- Department of Zoology, University of British Columbia, Vancouver, Canada.,Graduate Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada
| | - Jane Wang
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Jeffrey Lin
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Kathy Kyungeun Lee
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Arpun Johal
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Kota Mizumoto
- Department of Zoology, University of British Columbia, Vancouver, Canada.,Graduate Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada.,Life Sciences Institute, University of British Columbia, Vancouver, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
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24
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Gucy2d selectively marks inhibitory dynorphin neurons in the spinal dorsal horn but is dispensable for pain and itch sensitivity. Pain Rep 2021; 6:e947. [PMID: 34296052 PMCID: PMC8291471 DOI: 10.1097/pr9.0000000000000947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/08/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction Inhibitory neurons in the spinal dorsal horn can be classified based on expression of neurochemical marker genes. However, these marker genes are often expressed throughout the central nervous system, which poses challenges for manipulating genetically identified spinal neurons without undesired off-target effects. Objectives We investigated whether Gucy2d, previously identified as a highly selective marker of dynorphin-lineage neurons in the dorsal horn, is expressed in other locations within the adult mouse spinal cord, dorsal root ganglia (DRG), or brain. In addition, we sought to molecularly characterize Gucy2d-expressing dorsal horn neurons and investigate whether the disruption of Gucy2d gene expression affects sensitivity to itch or pain. Methods In situ hybridization experiments assessed Gucy2d mRNA expression in the adult mouse spinal cord, DRG, and brain, and its colocalization with Pax2, Bhlhb5, and Pde2a in dorsal horn neurons. Knockout mice lacking Gucy2d expression were compared with littermate controls to assess sensitivity to chloroquine-induced itch and dry skin-mediated chronic itch, as well as heat, cold, or mechanical stimuli. Results Gucy2d is selectively expressed in dynorphin-lineage neurons in lamina I-III of the adult mouse spinal cord but not in the brain or DRG. Spinal Gucy2d-expressing neurons are inhibitory neurons that also express the transcription factor Bhlhb5 and the cGMP-dependent phosphodiesterase Pde2a. Gucy2d knockout mice did not exhibit altered responses to itch or pain. Conclusions The selective expression of Gucy2d within a subpopulation of inhibitory dorsal horn neurons may yield a means to selectively manipulate inhibitory signaling at the level of the spinal cord without effects on the brain.
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25
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Monteiro FA, Miranda RM, Samina MC, Dias AF, Raposo AASF, Oliveira P, Reguenga C, Castro DS, Lima D. Tlx3 Exerts Direct Control in Specifying Excitatory Over Inhibitory Neurons in the Dorsal Spinal Cord. Front Cell Dev Biol 2021; 9:642697. [PMID: 33996801 PMCID: PMC8117147 DOI: 10.3389/fcell.2021.642697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/30/2021] [Indexed: 11/28/2022] Open
Abstract
The spinal cord dorsal horn is a major station for integration and relay of somatosensory information and comprises both excitatory and inhibitory neuronal populations. The homeobox gene Tlx3 acts as a selector gene to control the development of late-born excitatory (dILB) neurons by specifying glutamatergic transmitter fate in dorsal spinal cord. However, since Tlx3 direct transcriptional targets remain largely unknown, it remains to be uncovered how Tlx3 functions to promote excitatory cell fate. Here we combined a genomics approach based on chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq) and expression profiling, with validation experiments in Tlx3 null embryos, to characterize the transcriptional program of Tlx3 in mouse embryonic dorsal spinal cord. We found most dILB neuron specific genes previously identified to be directly activated by Tlx3. Surprisingly, we found Tlx3 also directly represses many genes associated with the alternative inhibitory dILA neuronal fate. In both cases, direct targets include transcription factors and terminal differentiation genes, showing that Tlx3 directly controls cell identity at distinct levels. Our findings provide a molecular frame for the master regulatory role of Tlx3 in developing glutamatergic dILB neurons. In addition, they suggest a novel function for Tlx3 as direct repressor of GABAergic dILA identity, pointing to how generation of the two alternative cell fates being tightly coupled.
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Affiliation(s)
- Filipe A Monteiro
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Rafael M Miranda
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Marta C Samina
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Ana F Dias
- Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Alexandre A S F Raposo
- Molecular Neurobiology Group, Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Patrícia Oliveira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Diagnostics, Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal
| | - Carlos Reguenga
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Diogo S Castro
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Molecular Neurobiology Group, Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Stem Cells & Neurogenesis Group, Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Deolinda Lima
- Unidade de Biologia Experimental, Departamento de Biomedicina, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,Pain Research Group, Instituto de Biologia Molecular e Celular, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
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26
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Abstract
Inhibitory interneurons in the adult spinal dorsal horn (DH) can be neurochemically classified into subpopulations that regulate distinct somatosensory modalities. Although inhibitory networks in the rodent DH undergo dramatic remodeling over the first weeks of life, little is known about the maturation of identified classes of GABAergic interneurons, or whether their role in somatosensation shifts during development. We investigated age-dependent changes in the connectivity and function of prodynorphin (DYN)-lineage neurons in the mouse DH that suppress mechanosensation and itch during adulthood. In vitro patch clamp recordings revealed a developmental increase in primary afferent drive to DYN interneurons and a transition from exclusive C-fiber monosynaptic input to mixed A-fiber and C-fiber innervation. Although most adult DYN interneurons exhibited tonic firing as expected from their inhibitory phenotype, neonatal and adolescent DYN cells were predominantly classified as phasic or single-spiking. Importantly, we also found that most of the inhibitory presynaptic terminals contacting lamina I spinoparabrachial projection neurons (PNs) originate from DYN neurons. Furthermore, inhibitory synaptic input from DYN interneurons onto PNs was weaker during the neonatal period, likely reflecting a lower number of GABAergic terminals and a reduced probability of GABA release compared to adults. Finally, spinal DYN interneurons attenuated mechanical sensitivity throughout development, but this population dampened acute nonhistaminergic itch only during adulthood. Collectively, these findings suggest that the spinal "gates" controlling sensory transmission to the brain may emerge in a modality-selective manner during early life due to the postnatal tuning of inhibitory synaptic circuits within the DH.
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27
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Motojima Y, Ueta Y, Sakai A. Analysis of the proportion and neuronal activity of excitatory and inhibitory neurons in the rat dorsal spinal cord after peripheral nerve injury. Neurosci Lett 2021; 749:135707. [PMID: 33600905 DOI: 10.1016/j.neulet.2021.135707] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/06/2021] [Accepted: 01/29/2021] [Indexed: 12/12/2022]
Abstract
The dorsal spinal cord contains projection neurons that transmit somatosensory information to the brain and interneurons which then modulate neuronal activity of these projection neurons and/or other interneurons. Interneurons can be subdivided into two groups: excitatory and inhibitory neurons. While inhibitory interneurons are thought to play a crucial role in analgesia, it is unclear whether they are involved in neuropathic pain. In the present study, we aimed to assess the proportion and neuronal activity of excitatory/inhibitory neurons in the dorsal spinal cord using a neuropathic pain model in rats. Following partial sciatic nerve ligation (PSNL), rats showed significant mechanical hyperalgesia, and subsequent immunohistochemical studies were conducted in laminae I-III of the dorsal spinal cord. We found that the number of FosB-immunoreactive cells was significantly higher; there was no change in the percentage of Pax2 positive/negative neurons in NeuN positive neurons; Pax2 negative neurons, but not Pax2 positive neurons, were predominantly activated in PSNL rats; and the immunofluorescence intensity of the calcium channel α2δ1 subunit was significantly higher. These results indicate that while peripheral nerve injury might not affect the proportion of excitatory and inhibitory neurons, it predominantly activates excitatory neurons in laminae I-III of the rat dorsal spinal cord.
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Affiliation(s)
- Yasuhito Motojima
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan.
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
| | - Akinori Sakai
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, 807-8555, Japan
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28
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Liu F, Zhang Y, Chen F, Yuan J, Li S, Han S, Lu D, Geng J, Rao Z, Sun L, Xu J, Shi Y, Wang X, Liu Y. Neurog2 directly converts astrocytes into functional neurons in midbrain and spinal cord. Cell Death Dis 2021; 12:225. [PMID: 33649354 PMCID: PMC7921562 DOI: 10.1038/s41419-021-03498-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 01/03/2021] [Accepted: 01/08/2021] [Indexed: 12/16/2022]
Abstract
Conversion of astrocytes into neurons in vivo offers an alternative therapeutic approach for neuronal loss after injury or disease. However, not only the efficiency of the conversion of astrocytes into functional neurons by single Neurog2, but also the conundrum that whether Neurog2-induced neuronal cells (Neurog2-iNs) are further functionally integrated into existing matured neural circuits remains unknown. Here, we adopted the AAV(2/8) delivery system to overexpress single factor Neurog2 into astrocytes and found that the majority of astrocytes were successfully converted into neuronal cells in multiple brain regions, including the midbrain and spinal cord. In the midbrain, Neurog2-induced neuronal cells (Neurog2-iNs) exhibit neuronal morphology, mature electrophysiological properties, glutamatergic identity (about 60%), and synapse-like configuration local circuits. In the spinal cord, astrocytes from both the intact and lesioned sources could be converted into functional neurons with ectopic expression of Neurog2 alone. Notably, further evidence from our study also proves that Neurog2-iNs in the intact spinal cord are capable of responding to diverse afferent inputs from dorsal root ganglion (DRG). Together, this study does not merely demonstrate the feasibility of Neurog2 for efficient in vivo reprogramming, it gives an indication for the Neurog2-iNs as a functional and potential factor in cell-replacement therapy.
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Affiliation(s)
- Fei Liu
- Anhui Clinical and Preclinical Key Laboratory of Respiratory Disease; Molecular Diagnosis Center, Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, 233000, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yijie Zhang
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fuliang Chen
- Department of Immunology, School of Laboratory Medicine, Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu, Anhui, 233030, China
| | - Jiacheng Yuan
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sanlan Li
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sue Han
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dengyu Lu
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Junlan Geng
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhiping Rao
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li Sun
- Department of Radiation Oncology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, 233004, China
| | - Jianhua Xu
- Department of Neurology, Jiading District Central Hospital Affiliated to Shanghai University of Medicine & Health Sciences, Shanghai, 201800, China
| | - Yuhan Shi
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xiaojing Wang
- Anhui Clinical and Preclinical Key Laboratory of Respiratory Disease; Molecular Diagnosis Center, Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, 233000, China.
| | - Yueguang Liu
- Department of Neurology, Jiading District Central Hospital Affiliated to Shanghai University of Medicine & Health Sciences, Shanghai, 201800, China.
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29
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Spinal Excitatory Dynorphinergic Interneurons Contribute to Burn Injury-Induced Nociception Mediated by Phosphorylated Histone 3 at Serine 10 in Rodents. Int J Mol Sci 2021; 22:ijms22052297. [PMID: 33669046 PMCID: PMC7956488 DOI: 10.3390/ijms22052297] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/20/2021] [Accepted: 02/21/2021] [Indexed: 12/18/2022] Open
Abstract
The phosphorylation of serine 10 in histone 3 (p-S10H3) has recently been demonstrated to participate in spinal nociceptive processing. However, superficial dorsal horn (SDH) neurons involved in p-S10H3-mediated nociception have not been fully characterized. In the present work, we combined immunohistochemistry, in situ hybridization with the retrograde labeling of projection neurons to reveal the subset of dorsal horn neurons presenting an elevated level of p-S10H3 in response to noxious heat (60 °C), causing burn injury. Projection neurons only represented a small percentage (5%) of p-S10H3-positive cells, while the greater part of them belonged to excitatory SDH interneurons. The combined immunolabeling of p-S10H3 with markers of already established interneuronal classes of the SDH revealed that the largest subset of neurons with burn injury-induced p-S10H3 expression was dynorphin immunopositive in mice. Furthermore, the majority of p-S10H3-expressing dynorphinergic neurons proved to be excitatory, as they lacked Pax-2 and showed Lmx1b-immunopositivity. Thus, we showed that neurochemically heterogeneous SDH neurons exhibit the upregulation of p-S10H3 shortly after noxious heat-induced burn injury and consequential tissue damage, and that a dedicated subset of excitatory dynorphinergic neurons is likely a key player in the development of central sensitization via the p-S10H3 mediated pathway.
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30
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Ma T, Wong SZH, Lee B, Ming GL, Song H. Decoding neuronal composition and ontogeny of individual hypothalamic nuclei. Neuron 2021; 109:1150-1167.e6. [PMID: 33600763 DOI: 10.1016/j.neuron.2021.01.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 10/10/2020] [Accepted: 01/26/2021] [Indexed: 01/30/2023]
Abstract
The hypothalamus plays crucial roles in regulating endocrine, autonomic, and behavioral functions via its diverse nuclei and neuronal subtypes. The developmental mechanisms underlying ontogenetic establishment of different hypothalamic nuclei and generation of neuronal diversity remain largely unknown. Here, we show that combinatorial T-box 3 (TBX3), orthopedia homeobox (OTP), and distal-less homeobox (DLX) expression delineates all arcuate nucleus (Arc) neurons and defines four distinct subpopulations, whereas combinatorial NKX2.1/SF1 and OTP/DLX expression identifies ventromedial hypothalamus (VMH) and tuberal nucleus (TuN) neuronal subpopulations, respectively. Developmental analysis indicates that all four Arc subpopulations are mosaically and simultaneously generated from embryonic Arc progenitors, whereas glutamatergic VMH neurons and GABAergic TuN neurons are sequentially generated from common embryonic VMH progenitors. Moreover, clonal lineage-tracing analysis reveals that diverse lineages from multipotent radial glia progenitors orchestrate Arc and VMH-TuN establishment. Together, our study reveals cellular mechanisms underlying generation and organization of diverse neuronal subtypes and ontogenetic establishment of individual nuclei in the mammalian hypothalamus.
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Affiliation(s)
- Tong Ma
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Samuel Zheng Hao Wong
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; The Cellular and Molecular Medicine Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bora Lee
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Guo-Li Ming
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongjun Song
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; The Epigenetic Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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31
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England SJ, Cerda GA, Kowalchuk A, Sorice T, Grieb G, Lewis KE. Hmx3a Has Essential Functions in Zebrafish Spinal Cord, Ear and Lateral Line Development. Genetics 2020; 216:1153-1185. [PMID: 33077489 PMCID: PMC7768253 DOI: 10.1534/genetics.120.303748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/14/2020] [Indexed: 11/30/2022] Open
Abstract
Transcription factors that contain a homeodomain DNA-binding domain have crucial functions in most aspects of cellular function and embryonic development in both animals and plants. Hmx proteins are a subfamily of NK homeodomain-containing proteins that have fundamental roles in development of sensory structures such as the eye and the ear. However, Hmx functions in spinal cord development have not been analyzed. Here, we show that zebrafish (Danio rerio) hmx2 and hmx3a are coexpressed in spinal dI2 and V1 interneurons, whereas hmx3b, hmx1, and hmx4 are not expressed in spinal cord. Using mutational analyses, we demonstrate that, in addition to its previously reported role in ear development, hmx3a is required for correct specification of a subset of spinal interneuron neurotransmitter phenotypes, as well as correct lateral line progression and survival to adulthood. Surprisingly, despite similar expression patterns of hmx2 and hmx3a during embryonic development, zebrafish hmx2 mutants are viable and have no obviously abnormal phenotypes in sensory structures or neurons that require hmx3a In addition, embryos homozygous for deletions of both hmx2 and hmx3a have identical phenotypes to severe hmx3a single mutants. However, mutating hmx2 in hypomorphic hmx3a mutants that usually develop normally, results in abnormal ear and lateral line phenotypes. This suggests that while hmx2 cannot compensate for loss of hmx3a, it does function in these developmental processes, although to a much lesser extent than hmx3a More surprisingly, our mutational analyses suggest that Hmx3a may not require its homeodomain DNA-binding domain for its roles in viability or embryonic development.
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Affiliation(s)
| | - Gustavo A Cerda
- Department of Physiology, Development and Neuroscience, University of Cambridge, CB2 3DY, UK
| | | | - Taylor Sorice
- Department of Biology, Syracuse University, New York 13244
| | - Ginny Grieb
- Department of Biology, Syracuse University, New York 13244
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Spinal Inhibitory Ptf1a-Derived Neurons Prevent Self-Generated Itch. Cell Rep 2020; 33:108422. [PMID: 33238109 DOI: 10.1016/j.celrep.2020.108422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/27/2020] [Accepted: 11/02/2020] [Indexed: 01/13/2023] Open
Abstract
Chronic itch represents an incapacitating burden on patients suffering from a spectrum of diseases. Despite recent advances in our understanding of the cells and circuits implicated in the processing of itch information, chronic itch often presents itself without an apparent cause. Here, we identify a spinal subpopulation of inhibitory neurons defined by the expression of Ptf1a, involved in gating mechanosensory information self-generated during movement. These neurons receive tactile and motor input and establish presynaptic inhibitory contacts on mechanosensory afferents. Loss of Ptf1a neurons leads to increased hairy skin sensitivity and chronic itch, partially mediated by the classic itch pathway involving gastrin-releasing peptide receptor (GRPR) spinal neurons. Conversely, chemogenetic activation of GRPR neurons elicits itch, which is suppressed by concomitant activation of Ptf1a neurons. These findings shed light on the circuit mechanisms implicated in chronic itch and open novel targets for therapy developments.
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A spinal neural circuitry for converting touch to itch sensation. Nat Commun 2020; 11:5074. [PMID: 33033265 PMCID: PMC7545208 DOI: 10.1038/s41467-020-18895-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/17/2020] [Indexed: 12/14/2022] Open
Abstract
Touch and itch sensations are crucial for evoking defensive and emotional responses, and light tactile touch may induce unpleasant itch sensations (mechanical itch or alloknesis). The neural substrate for touch-to-itch conversion in the spinal cord remains elusive. We report that spinal interneurons expressing Tachykinin 2-Cre (Tac2Cre) receive direct Aβ low threshold mechanoreceptor (LTMR) input and form monosynaptic connections with GRPR neurons. Ablation or inhibition markedly reduces mechanical but not acute chemical itch nor noxious touch information. Chemogenetic inhibition of Tac2Cre neurons also displays pronounced deficit in chronic dry skin itch, a type of chemical itch in mice. Consistently, ablation of gastrin-releasing peptide receptor (GRPR) neurons, which are essential for transmitting chemical itch, also abolishes mechanical itch. Together, these results suggest that innocuous touch and chemical itch information converge on GRPR neurons and thus map an exquisite spinal circuitry hard-wired for converting innocuous touch to irritating itch.
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Yvone GM, Chavez-Martinez CL, Nguyen AR, Wang DJ, Phelps PE. Reelin dorsal horn neurons co-express Lmx1b and are mispositioned in disabled-1 mutant mice. Eur J Neurosci 2020; 52:3322-3338. [PMID: 32492253 PMCID: PMC9451954 DOI: 10.1111/ejn.14847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 11/30/2022]
Abstract
Mice missing either Reelin or Disabled-1 (Dab1) exhibit dorsal horn neuronal positioning errors and display heat hypersensitivity and mechanical insensitivity. Reelin binds its receptors, apolipoprotein E receptor 2 and very low-density lipoprotein receptor, leading to the recruitment and phosphorylation of Dab1 and activation of downstream pathways that regulate neuronal migration. Previously, we reported that 70% of Dab1 laminae I-II neurons co-expressed LIM-homeobox transcription factor 1-beta (Lmx1b). Here, we asked whether Reelin-expressing dorsal horn neurons co-express Lmx1b, are mispositioned in dab1 mutants, and contribute to nociceptive abnormalities. About 90% of Reelin-labeled neurons are Lmx1b-positive in laminae I-II, confirming that most Reelin and Dab1 neurons are glutamatergic. We determined that Reelin-Lmx1b and Dab1-Lmx1b dorsal horn neurons are separate populations, and together, comprise 37% of Lmx1b-positive cells within and above the Isolectin B4 (IB4) layer in wild-type mice. Compared to wild-type mice, dab1 mutants have a reduced area of laminae I-II outer (above the IB4 layer), more Reelin-Lmx1b neurons within the IB4 layer, and fewer Reelin-Lmx1b neurons within the lateral reticulated area of lamina V and lateral spinal nucleus. Interestingly, both Reelin- and Dab1-labeled dorsal horn neurons sustain similar positioning errors in mutant mice. After noxious thermal and mechanical stimulation, Reelin, Lmx1b, and Reelin-Lmx1b neurons expressed Fos in laminae I-II and the lateral reticulated area in wild-type mice and, therefore, participate in nociceptive circuits. Together, our data suggest that disruption of the Reelin-signaling pathway results in neuroanatomical abnormalities that contribute to the nociceptive changes that characterize these mutant mice.
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Affiliation(s)
- Griselda M Yvone
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA, USA
| | | | - Amanda R Nguyen
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA, USA
| | - Deborah J Wang
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA, USA
| | - Patricia E Phelps
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA, USA
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Transcriptional profile of spinal dynorphin-lineage interneurons in the developing mouse. Pain 2020; 160:2380-2397. [PMID: 31166300 DOI: 10.1097/j.pain.0000000000001636] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mounting evidence suggests that the spinal dorsal horn (SDH) contains multiple subpopulations of inhibitory interneurons that play distinct roles in somatosensory processing, as exemplified by the importance of spinal dynorphin-expressing neurons for the suppression of mechanical pain and chemical itch. Although it is clear that GABAergic transmission in the SDH undergoes significant alterations during early postnatal development, little is known about the maturation of discrete inhibitory "microcircuits" within the region. As a result, the goal of this study was to elucidate the gene expression profile of spinal dynorphin (pDyn)-lineage neurons throughout life. We isolated nuclear RNA specifically from pDyn-lineage SDH interneurons at postnatal days 7, 21, and 80 using the Isolation of Nuclei Tagged in Specific Cell Types (INTACT) technique, followed by RNA-seq analysis. Over 650 genes were ≥2-fold enriched in adult pDyn nuclei compared with non-pDyn spinal cord nuclei, including targets with known relevance to pain such as galanin (Gal), prepronociceptin (Pnoc), and nitric oxide synthase 1 (Nos1). In addition, the gene encoding a membrane-bound guanylate cyclase, Gucy2d, was identified as a novel and highly selective marker of the pDyn population within the SDH. Differential gene expression analysis comparing pDyn nuclei across the 3 ages revealed sets of genes that were significantly upregulated (such as Cartpt, encoding cocaine- and amphetamine-regulated transcript peptide) or downregulated (including Npbwr1, encoding the receptor for neuropeptides B/W) during postnatal development. Collectively, these results provide new insight into the potential molecular mechanisms underlying the known age-dependent changes in spinal nociceptive processing and pain sensitivity.
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Hughes DI, Todd AJ. Central Nervous System Targets: Inhibitory Interneurons in the Spinal Cord. Neurotherapeutics 2020; 17:874-885. [PMID: 33029722 PMCID: PMC7641291 DOI: 10.1007/s13311-020-00936-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 12/15/2022] Open
Abstract
Pain is a percept of critical importance to our daily survival. In most cases, it serves both an adaptive function by helping us respond appropriately in a potentially hostile environment and also a protective role by alerting us to tissue damage. Normally, it is evoked by the activation of peripheral nociceptive nerve endings and the subsequent relay of information to distinct cortical and sub-cortical regions, but under pathological conditions that result in chronic pain, it can become spontaneous. Given that one in three chronic pain patients do not respond to the treatments currently available, the need for more effective analgesics is evident. Two principal obstacles to the development of novel analgesic therapies are our limited understanding of how neuronal circuits that comprise these pain pathways transmit and modulate sensory information under normal circumstances and how these circuits change under pathological conditions leading to chronic pain states. In this review, we focus on the role of inhibitory interneurons in setting pain thresholds and, in particular, how disinhibition in the spinal dorsal horn can lead to aberrant sensory processing associated with chronic pain states.
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Affiliation(s)
- David I Hughes
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland.
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland
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Tran M, Braz JM, Hamel K, Kuhn J, Todd AJ, Basbaum AI. Ablation of spinal cord estrogen receptor α-expressing interneurons reduces chemically induced modalities of pain and itch. J Comp Neurol 2020; 528:1629-1643. [PMID: 31872868 PMCID: PMC7317200 DOI: 10.1002/cne.24847] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/13/2019] [Accepted: 12/16/2019] [Indexed: 11/13/2022]
Abstract
Estrogens are presumed to underlie, at least in part, the greater pain sensitivity and chronic pain prevalence that women experience compared to men. Although previous studies revealed populations of estrogen receptor-expressing neurons in primary afferents and in superficial dorsal horn neurons, there is little to no information as to the contribution of these neurons to the generation of acute and chronic pain. Here we molecularly characterized neurons in the mouse superficial spinal cord dorsal horn that express estrogen receptor α (ERα) and explored the behavioral consequences of their ablation. We found that spinal ERα-positive neurons are largely excitatory interneurons and many coexpress substance P, a marker for a discrete subset of nociceptive, excitatory interneurons. After viral, caspase-mediated ablation of spinal ERα-expressing cells, we observed a significant decrease in the first phase of the formalin test, but in male mice only. ERα-expressing neuron-ablation also reduced pruritogen-induced scratching in both male and female mice. There were no ablation-related changes in mechanical or heat withdrawal thresholds or in capsaicin-induced nocifensive behavior. In chronic pain models, we found no change in Complete Freund's adjuvant-induced thermal or mechanical hypersensitivity, or in partial sciatic nerve injury-induced mechanical allodynia. We conclude that ERα labels a subpopulation of excitatory interneurons that are specifically involved in chemically evoked persistent pain and pruritogen-induced itch.
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Affiliation(s)
- May Tran
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Joao Manuel Braz
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Katherine Hamel
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Julia Kuhn
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Andrew J. Todd
- Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Allan I. Basbaum
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
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Estacio-Gómez A, Hassan A, Walmsley E, Le LW, Southall TD. Dynamic neurotransmitter specific transcription factor expression profiles during Drosophila development. Biol Open 2020; 9:9/5/bio052928. [PMID: 32493733 PMCID: PMC7286294 DOI: 10.1242/bio.052928] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The remarkable diversity of neurons in the nervous system is generated during development, when properties such as cell morphology, receptor profiles and neurotransmitter identities are specified. In order to gain a greater understanding of neurotransmitter specification we profiled the transcription state of cholinergic, GABAergic and glutamatergic neurons in vivo at three developmental time points. We identified 86 differentially expressed transcription factors that are uniquely enriched, or uniquely depleted, in a specific neurotransmitter type. Some transcription factors show a similar profile across development, others only show enrichment or depletion at specific developmental stages. Profiling of Acj6 (cholinergic enriched) and Ets65A (cholinergic depleted) binding sites in vivo reveals that they both directly bind the ChAT locus, in addition to a wide spectrum of other key neuronal differentiation genes. We also show that cholinergic enriched transcription factors are expressed in mostly non-overlapping populations in the adult brain, implying the absence of combinatorial regulation of neurotransmitter fate in this context. Furthermore, our data underlines that, similar to Caenorhabditis elegans, there are no simple transcription factor codes for neurotransmitter type specification. This article has an associated First Person interview with the first author of the paper. Summary: Transcriptome profiling of cholinergic, GABAergic and glutamatergic neurons in Drosophila identified multiple transcription factors as potential regulators of neurotransmitter fate.
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Affiliation(s)
- Alicia Estacio-Gómez
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Amira Hassan
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Emma Walmsley
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Lily Wong Le
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
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Gray de Cristoforis A, Ferrari F, Clotman F, Vogel T. Differentiation and localization of interneurons in the developing spinal cord depends on DOT1L expression. Mol Brain 2020; 13:85. [PMID: 32471461 PMCID: PMC7260853 DOI: 10.1186/s13041-020-00623-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/18/2020] [Indexed: 11/12/2022] Open
Abstract
Genetic and epigenetic factors contribute to the development of the spinal cord. Failure in correct exertion of the developmental programs, including neurulation, neural tube closure and neurogenesis of the diverse spinal cord neuronal subtypes results in defects of variable severity. We here report on the histone methyltransferase Disruptor of Telomeric 1 Like (DOT1L), which mediates histone H3 lysine 79 (H3K79) methylation. Conditional inactivation of DOT1L using Wnt1-cre as driver (Dot1l-cKO) showed that DOT1L expression is essential for spinal cord neurogenesis and localization of diverse neuronal subtypes, similar to its function in the development of the cerebral cortex and cerebellum. Transcriptome analysis revealed that DOT1L deficiency favored differentiation over progenitor proliferation. Dot1l-cKO mainly decreased the numbers of dI1 interneurons expressing Lhx2. In contrast, Lhx9 expressing dI1 interneurons did not change in numbers but localized differently upon Dot1l-cKO. Similarly, loss of DOT1L affected localization but not generation of dI2, dI3, dI5, V0 and V1 interneurons. The resulting derailed interneuron patterns might be responsible for increased cell death, occurrence of which was restricted to the late developmental stage E18.5. Together our data indicate that DOT1L is essential for subtype-specific neurogenesis, migration and localization of dorsal and ventral interneurons in the developing spinal cord, in part by regulating transcriptional activation of Lhx2.
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Affiliation(s)
- Angelica Gray de Cristoforis
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Francesco Ferrari
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Frédéric Clotman
- Laboratory of Neural Differentiation, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Tanja Vogel
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.
- Centre for Basics in Neuromodulation (Neuromodul Basics), Freiburg, Germany.
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Non-coding RNAs in neuropathic pain. Neuronal Signal 2020; 4:NS20190099. [PMID: 32587755 PMCID: PMC7306520 DOI: 10.1042/ns20190099] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 02/07/2023] Open
Abstract
Neuro-immune alterations in the peripheral and central nervous system play a role in the pathophysiology of chronic pain in general, and members of the non-coding RNA (ncRNA) family, specifically the short, 22 nucleotide microRNAs (miRNAs) and the long non-coding RNAs (lncRNAs) act as master switches orchestrating both immune as well as neuronal processes. Several chronic disorders reveal unique ncRNA expression signatures, which recently generated big hopes for new perspectives for the development of diagnostic applications. lncRNAs may offer perspectives as candidates indicative of neuropathic pain in liquid biopsies. Numerous studies have provided novel mechanistic insight into the role of miRNAs in the molecular sequelae involved in the pathogenesis of neuropathic pain along the entire pain pathway. Specific processes within neurons, immune cells, and glia as the cellular components of the neuropathic pain triad and the communication paths between them are controlled by specific miRNAs. Therefore, nucleotide sequences mimicking or antagonizing miRNA actions can provide novel therapeutic strategies for pain treatment, provided their human homologues serve the same or similar functions. Increasing evidence also sheds light on the function of lncRNAs, which converge so far mainly on purinergic signalling pathways both in neurons and glia, and possibly even other ncRNA species that have not been explored so far.
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Kumamaru H, Lu P, Rosenzweig ES, Kadoya K, Tuszynski MH. Regenerating Corticospinal Axons Innervate Phenotypically Appropriate Neurons within Neural Stem Cell Grafts. Cell Rep 2020; 26:2329-2339.e4. [PMID: 30811984 PMCID: PMC6487864 DOI: 10.1016/j.celrep.2019.01.099] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/01/2018] [Accepted: 01/28/2019] [Indexed: 01/13/2023] Open
Abstract
Neural progenitor cell grafts form new relays across sites of spinal cord injury (SCI). Using a panel of neuronal markers, we demonstrate that spinal neural progenitor grafts to sites of rodent SCI adopt diverse spinal motor and sensory interneuronal fates, representing most neuronal subtypes of the intact spinal cord, and spontaneously segregate into domains of distinct cell clusters. Host corticospinal motor axons regenerating into neural progenitor grafts innervate appropriate pre-motor interneurons, based on trans-synaptic tracing with herpes simplex virus. A human spinal neural progenitor cell graft to a non-human primate also received topographically appropriate corticospinal axon regeneration. Thus, grafted spinal neural progenitor cells give rise to a variety of neuronal progeny that are typical of the normal spinal cord; remarkably, regenerating injured adult corticospinal motor axons spontaneously locate appropriate motor domains in the heterogeneous, developing graft environment, without a need for additional exogenous guidance. Kumamaru et al. demonstrate that spinal cord neural progenitor cell grafts spontaneously segregate into motor and sensory domains when implanted into sites of spinal cord injury in rats and primates. Host corticospinal axons regenerating into grafts preferentially regenerate and synapse onto motor interneuron-rich domains, avoiding inappropriate sensory domains.
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Affiliation(s)
- Hiromi Kumamaru
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Department of Orthopaedic Surgery, Kyushu University Beppu Hospital, Oita, Japan
| | - Paul Lu
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Veterans Administration San Diego Healthcare System, San Diego, CA, USA
| | - Ephron S Rosenzweig
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Ken Kadoya
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Department of Orthopaedic Surgery, Hokkaido University, Sapporo, Japan
| | - Mark H Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Veterans Administration San Diego Healthcare System, San Diego, CA, USA.
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Neonatal Injury Evokes Persistent Deficits in Dynorphin Inhibitory Circuits within the Adult Mouse Superficial Dorsal Horn. J Neurosci 2020; 40:3882-3895. [PMID: 32291327 DOI: 10.1523/jneurosci.0029-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/18/2020] [Accepted: 04/04/2020] [Indexed: 12/22/2022] Open
Abstract
Neonatal tissue damage induces long-term deficits in inhibitory synaptic transmission within the spinal superficial dorsal horn (SDH) that include a reduction in primary afferent-evoked, feedforward inhibition onto adult projection neurons. However, the subpopulations of mature GABAergic interneurons which are compromised by early-life injury have yet to be identified. The present research illuminates the persistent effects of neonatal surgical injury on the function of inhibitory SDH interneurons derived from the prodynorphin (DYN) lineage, a population that synapses directly onto lamina I spinoparabrachial neurons and is known to suppress mechanical pain and itch in adults. The results demonstrate that hindpaw incision at postnatal day 3 (P3) significantly decreased the strength of primary afferent-evoked glutamatergic drive onto DYN neurons within the adult mouse SDH while increasing the appearance of afferent-evoked inhibition onto the same population. Neonatal injury also dampened the intrinsic membrane excitability of mature DYN neurons, and reduced their action potential discharge in response to sensory input, compared with naive littermate controls. Furthermore, P3 incision decreased the efficacy of inhibitory DYN synapses onto adult spinoparabrachial neurons, which reflected a prolonged reduction in the probability of GABA release. Collectively, the data suggest that early-life tissue damage may persistently constrain the ability of spinal DYN interneurons to limit ascending nociceptive transmission to the adult brain. This is predicted to contribute to the loss of feedforward inhibition onto mature projection neurons, and the "priming" of nociceptive circuits in the developing spinal cord, following injuries during the neonatal period.SIGNIFICANCE STATEMENT Neonatal injury has lasting effects on pain processing in the adult CNS, including a reduction in feedforward inhibition onto ascending projection neurons in the spinal dorsal horn. While it is clear that spinal GABAergic interneurons are comprised of multiple subpopulations that play distinct roles in somatosensation, the identity of those interneurons which are compromised by tissue damage during early life remains unknown. Here we document persistent deficits in spinal inhibitory circuits involving dynorphin-lineage interneurons previously implicated in gating mechanical pain and itch. Notably, neonatal injury reduced the strength of dynorphin-lineage inhibitory synapses onto mature lamina I spinoparabrachial neurons, a major output of the spinal nociceptive network, which could contribute to the priming of pain pathways by early tissue damage.
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Mona B, Villarreal J, Savage TK, Kollipara RK, Boisvert BE, Johnson JE. Positive autofeedback regulation of Ptf1a transcription generates the levels of PTF1A required to generate itch circuit neurons. Genes Dev 2020; 34:621-636. [PMID: 32241803 PMCID: PMC7197352 DOI: 10.1101/gad.332577.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 03/13/2020] [Indexed: 11/24/2022]
Abstract
In this study, Mona et al. set out to investigate the role of Ptf1a in specifying a subset of dorsal spinal cord inhibitory neurons in mice in vivo. The authors used CRISPR to target multiple noncoding sequences with putative cis-regulatory activity controlling Ptf1a and demonstrate a requirement for positive transcriptional autoregulatory feedback to attain the levels of PTF1A necessary for generating correctly balanced neuronal circuits. Peripheral somatosensory input is modulated in the dorsal spinal cord by a network of excitatory and inhibitory interneurons. PTF1A is a transcription factor essential in dorsal neural tube progenitors for specification of these inhibitory neurons. Thus, mechanisms regulating Ptf1a expression are key for generating neuronal circuits underlying somatosensory behaviors. Mutations targeted to distinct cis-regulatory elements for Ptf1a in mice, tested the in vivo contribution of each element individually and in combination. Mutations in an autoregulatory enhancer resulted in reduced levels of PTF1A, and reduced numbers of specific dorsal spinal cord inhibitory neurons, particularly those expressing Pdyn and Gal. Although these mutants survive postnatally, at ∼3–5 wk they elicit a severe scratching phenotype. Behaviorally, the mutants have increased sensitivity to itch, but acute sensitivity to other sensory stimuli such as mechanical or thermal pain is unaffected. We demonstrate a requirement for positive transcriptional autoregulatory feedback to attain the level of the neuronal specification factor PTF1A necessary for generating correctly balanced neuronal circuits.
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Affiliation(s)
- Bishakha Mona
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Juan Villarreal
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Trisha K Savage
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Rahul K Kollipara
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Brooke E Boisvert
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Jane E Johnson
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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Gbx1 and Gbx2 Are Essential for Normal Patterning and Development of Interneurons and Motor Neurons in the Embryonic Spinal Cord. J Dev Biol 2020; 8:jdb8020009. [PMID: 32244588 PMCID: PMC7345146 DOI: 10.3390/jdb8020009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/01/2020] [Accepted: 03/26/2020] [Indexed: 12/17/2022] Open
Abstract
The molecular mechanisms regulating neurogenesis involve the control of gene expression by transcription factors. Gbx1 and Gbx2, two members of the Gbx family of homeodomain-containing transcription factors, are known for their essential roles in central nervous system development. The expression domains of mouse Gbx1 and Gbx2 include regions of the forebrain, anterior hindbrain, and spinal cord. In the spinal cord, Gbx1 and Gbx2 are expressed in PAX2+ interneurons of the dorsal horn and ventral motor neuron progenitors. Based on their shared domains of expression and instances of overlap, we investigated the functional relationship between Gbx family members in the developing spinal cord using Gbx1−/−, Gbx2−/−, and Gbx1−/−/Gbx2−/− embryos. In situ hybridization analyses of embryonic spinal cords show upregulation of Gbx2 expression in Gbx1−/− embryos and upregulation of Gbx1 expression in Gbx2−/− embryos. Additionally, our data demonstrate that Gbx genes regulate development of a subset of PAX2+ dorsal inhibitory interneurons. While we observe no difference in overall proliferative status of the developing ependymal layer, expansion of proliferative cells into the anatomically defined mantle zone occurs in Gbx mutants. Lastly, our data shows a marked increase in apoptotic cell death in the ventral spinal cord of Gbx mutants during mid-embryonic stages. While our studies reveal that both members of the Gbx gene family are involved in development of subsets of PAX2+ dorsal interneurons and survival of ventral motor neurons, Gbx1 and Gbx2 are not sufficient to genetically compensate for the loss of one another. Thus, our studies provide novel insight to the relationship harbored between Gbx1 and Gbx2 in spinal cord development.
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45
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Feng W, Li Y, Dao P, Aburas J, Islam P, Elbaz B, Kolarzyk A, Brown AE, Kratsios P. A terminal selector prevents a Hox transcriptional switch to safeguard motor neuron identity throughout life. eLife 2020; 9:50065. [PMID: 31902393 PMCID: PMC6944445 DOI: 10.7554/elife.50065] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/08/2019] [Indexed: 01/01/2023] Open
Abstract
To become and remain functional, individual neuron types must select during development and maintain throughout life their distinct terminal identity features, such as expression of specific neurotransmitter receptors, ion channels and neuropeptides. Here, we report a molecular mechanism that enables cholinergic motor neurons (MNs) in the C. elegans ventral nerve cord to select and maintain their unique terminal identity. This mechanism relies on the dual function of the conserved terminal selector UNC-3 (Collier/Ebf). UNC-3 synergizes with LIN-39 (Scr/Dfd/Hox4-5) to directly co-activate multiple terminal identity traits specific to cholinergic MNs, but also antagonizes LIN-39’s ability to activate terminal features of alternative neuronal identities. Loss of unc-3 causes a switch in the transcriptional targets of LIN-39, thereby alternative, not cholinergic MN-specific, terminal features become activated and locomotion defects occur. The strategy of a terminal selector preventing a transcriptional switch may constitute a general principle for safeguarding neuronal identity throughout life.
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Affiliation(s)
- Weidong Feng
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States
| | - Yinan Li
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States
| | - Pauline Dao
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Jihad Aburas
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Priota Islam
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Benayahu Elbaz
- Department of Neurology, Center for Peripheral Neuropathy, University of Chicago, Chicago, United States
| | - Anna Kolarzyk
- Department of Neurology, Center for Peripheral Neuropathy, University of Chicago, Chicago, United States
| | - André Ex Brown
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States.,The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, United States
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46
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Identification of Spinal Neurons Contributing to the Dorsal Column Projection Mediating Fine Touch and Corrective Motor Movements. Neuron 2019; 104:749-764.e6. [PMID: 31586516 DOI: 10.1016/j.neuron.2019.08.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 07/22/2019] [Accepted: 08/16/2019] [Indexed: 12/22/2022]
Abstract
Tactile stimuli are integrated and processed by neuronal circuits in the deep dorsal horn of the spinal cord. Several spinal interneuron populations have been implicated in tactile information processing. However, dorsal horn projection neurons that contribute to the postsynaptic dorsal column (PSDC) pathway transmitting tactile information to the brain are poorly characterized. Here, we show that spinal neurons marked by the expression of Zic2creER mediate light touch sensitivity and textural discrimination. A subset of Zic2creER neurons are PSDC neurons that project to brainstem dorsal column nuclei, and chemogenetic activation of Zic2 PSDC neurons increases sensitivity to light touch stimuli. Zic2 neurons receive direct input from the cortex and brainstem motor nuclei and are required for corrective motor movements. These results suggest that Zic2 neurons integrate sensory input from cutaneous afferents with descending signals from the brain to promote corrective movements and transmit processed touch information back to the brain. VIDEO ABSTRACT.
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Gutierrez-Mecinas M, Bell A, Polgár E, Watanabe M, Todd AJ. Expression of Neuropeptide FF Defines a Population of Excitatory Interneurons in the Superficial Dorsal Horn of the Mouse Spinal Cord that Respond to Noxious and Pruritic Stimuli. Neuroscience 2019; 416:281-293. [PMID: 31421202 PMCID: PMC6839401 DOI: 10.1016/j.neuroscience.2019.08.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 07/15/2019] [Accepted: 08/06/2019] [Indexed: 12/16/2022]
Abstract
The great majority of neurons in the superficial dorsal horn of the spinal cord are excitatory interneurons, and these are required for the normal perception of pain and itch. We have previously identified 5 largely non-overlapping populations among these cells, based on the expression of four different neuropeptides (cholecystokinin, neurotensin, neurokinin B and substance P) and of green fluorescent protein driven by the promoter for gastrin-releasing peptide (GRP) in a transgenic mouse line. Another peptide (neuropeptide FF, NPFF) has been identified among the excitatory neurons, and here we have used an antibody against the NPFF precursor (pro-NPFF) and a probe that recognises Npff mRNA to identify and characterise these cells. We show that they are all excitatory interneurons, and are separate from the five populations listed above, accounting for ~ 6% of the excitatory neurons in laminae I-II. By examining phosphorylation of extracellular signal-regulated kinases, we show that the NPFF cells can respond to different types of noxious and pruritic stimulus. Ablation of somatostatin-expressing dorsal horn neurons has been shown to result in a dramatic reduction in mechanical pain sensitivity, while somatostatin released from these neurons is thought to contribute to itch. Since the great majority of the NPFF cells co-expressed somatostatin, these cells may play a role in the perception of pain and itch. NPFF is expressed by around 6% of the excitatory interneurons in the superficial dorsal horn of the mouse spinal cord. NPFF cells differ from those that express substance P, cholecystokinin, neurotensin or neurokinin B. Although some NPFF cells express gastrin-releasing peptide (GRP), they do not express GFP in a GRP-GFP mouse line. Some NPFF cells are activated by noxious or pruritic stimuli.
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Affiliation(s)
- Maria Gutierrez-Mecinas
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andrew Bell
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Erika Polgár
- Institute of Neuroscience and Psychology, 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
| | - 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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48
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Petitjean H, Bourojeni FB, Tsao D, Davidova A, Sotocinal SG, Mogil JS, Kania A, Sharif-Naeini R. Recruitment of Spinoparabrachial Neurons by Dorsal Horn Calretinin Neurons. Cell Rep 2019; 28:1429-1438.e4. [DOI: 10.1016/j.celrep.2019.07.048] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 06/13/2019] [Accepted: 07/15/2019] [Indexed: 01/11/2023] Open
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49
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Wang X, Yvone GM, Cilluffo M, Kim AS, Basbaum AI, Phelps PE. Mispositioned Neurokinin-1 Receptor-Expressing Neurons Underlie Heat Hyperalgesia in Disabled-1 Mutant Mice. eNeuro 2019; 6:ENEURO.0131-19.2019. [PMID: 31122949 PMCID: PMC6584071 DOI: 10.1523/eneuro.0131-19.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/11/2019] [Accepted: 05/15/2019] [Indexed: 11/30/2022] Open
Abstract
Reelin (Reln) and Disabled-1 (Dab1) participate in the Reln-signaling pathway and when either is deleted, mutant mice have the same spinally mediated behavioral abnormalities, increased sensitivity to noxious heat and a profound loss in mechanical sensitivity. Both Reln and Dab1 are highly expressed in dorsal horn areas that receive and convey nociceptive information, Laminae I-II, lateral Lamina V, and the lateral spinal nucleus (LSN). Lamina I contains both projection neurons and interneurons that express Neurokinin-1 receptors (NK1Rs) and they transmit information about noxious heat both within the dorsal horn and to the brain. Here, we ask whether the increased heat nociception in Reln and dab1 mutants is due to incorrectly positioned dorsal horn neurons that express NK1Rs. We found more NK1R-expressing neurons in Reln-/- and dab1-/- Laminae I-II than in their respective wild-type mice, and some NK1R neurons co-expressed Dab1 and the transcription factor Lmx1b, confirming their excitatory phenotype. Importantly, heat stimulation in dab1-/- mice induced Fos in incorrectly positioned NK1R neurons in Laminae I-II. Next, we asked whether these ectopically placed and noxious-heat responsive NK1R neurons participated in pain behavior. Ablation of the superficial NK1Rs with an intrathecal injection of a substance P analog conjugated to the toxin saporin (SSP-SAP) eliminated the thermal hypersensitivity of dab1-/- mice, without altering their mechanical insensitivity. These results suggest that ectopically positioned NK1R-expressing neurons underlie the heat hyperalgesia of Reelin-signaling pathway mutants, but do not contribute to their profound mechanical insensitivity.
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Affiliation(s)
- Xidao Wang
- Departments of Anatomy and Physiology and W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA 94158
| | - Griselda M Yvone
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Marianne Cilluffo
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Ashley S Kim
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Allan I Basbaum
- Departments of Anatomy and Physiology and W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA 94158
| | - Patricia E Phelps
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
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50
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Tulloch AJ, Teo S, Carvajal BV, Tessier-Lavigne M, Jaworski A. Diverse spinal commissural neuron populations revealed by fate mapping and molecular profiling using a novel Robo3 Cre mouse. J Comp Neurol 2019; 527:2948-2972. [PMID: 31152445 DOI: 10.1002/cne.24720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/22/2019] [Accepted: 05/21/2019] [Indexed: 12/19/2022]
Abstract
The two sides of the nervous system coordinate and integrate information via commissural neurons, which project axons across the midline. Commissural neurons in the spinal cord are a highly heterogeneous population of cells with respect to their birthplace, final cell body position, axonal trajectory, and neurotransmitter phenotype. Although commissural axon guidance during development has been studied in great detail, neither the developmental origins nor the mature phenotypes of commissural neurons have been characterized comprehensively, largely due to lack of selective genetic access to these neurons. Here, we generated mice expressing Cre recombinase from the Robo3 locus specifically in commissural neurons. We used Robo3 Cre mice to characterize the transcriptome and various origins of developing commissural neurons, revealing new details about their extensive heterogeneity in molecular makeup and developmental lineage. Further, we followed the fate of commissural neurons into adulthood, thereby elucidating their settling positions and molecular diversity and providing evidence for possible functions in various spinal cord circuits. Our studies establish an important genetic entry point for further analyses of commissural neuron development, connectivity, and function.
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Affiliation(s)
- Alastair J Tulloch
- Department of Neuroscience, Brown University, Providence, Rhode Island.,Robert J. and Nancy D. Carney Institute for Brain Science, Providence, Rhode Island
| | - Shaun Teo
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, New York
| | | | - Marc Tessier-Lavigne
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, New York.,Department of Biology, Stanford University, Stanford, California
| | - Alexander Jaworski
- Department of Neuroscience, Brown University, Providence, Rhode Island.,Robert J. and Nancy D. Carney Institute for Brain Science, Providence, Rhode Island
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