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Clowry GJ. Is there a consensus on the location and composition of the human subplate? J Comp Neurol 2024; 532:e25605. [PMID: 38454555 DOI: 10.1002/cne.25605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/16/2023] [Accepted: 02/27/2024] [Indexed: 03/09/2024]
Abstract
Cortical wall of human fetal cerebral cortex (early second trimester immunostained for a synaptic marker [red]) revealing the extent of the subplate, which is considerably wider than the cortical plate at this developmental stage.
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Affiliation(s)
- Gavin J Clowry
- Biosciences Institute and Centre for Transformative Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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2
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McLeod F, McDermott E, Mak S, Walsh D, Turnbull M, LeBeau FEN, Jackson A, Trevelyan AJ, Clowry GJ. AAV8 vector induced gliosis following neuronal transgene expression. Front Neurosci 2024; 18:1287228. [PMID: 38495109 PMCID: PMC10944330 DOI: 10.3389/fnins.2024.1287228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
Introduction Expression of light sensitive ion channels by selected neurons has been achieved by viral mediated transduction with gene constructs, but for this to have therapeutic uses, for instance in treating epilepsy, any adverse effects of viral infection on the cerebral cortex needs to be evaluated. Here, we assessed the impact of adeno-associated virus 8 (AAV8) carrying DNA code for a soma targeting light activated chloride channel/FusionRed (FR) construct under the CKIIa promoter. Methods Viral constructs were harvested from transfected HEK293 cells in vitro and purified. To test functionality of the opsin, cultured rodent neurons were transduced and the light response of transduced neurons was assayed using whole-cell patch-clamp recordings. In vivo expression was confirmed by immunofluorescence for FR. Unilateral intracranial injections of the viral construct were made into the mouse neocortex and non-invasive fluorescence imaging of FR expression made over 1-4 weeks post-injection using an IVIS Spectrum system. Sections were also prepared from injected mouse cortex for immunofluorescence staining of FR, alongside glial and neuronal marker proteins. Results In vitro, cortical neurons were successfully transduced, showing appropriate physiological responses to light stimulation. Following injections in vivo, transduction was progressively established around a focal injection site over a 4-week period with spread of transduction proportional to the concentration of virus introduced. Elevated GFAP immunoreactivity, a marker for reactive astrocytes, was detected near injection sites associated with, and proportional to, local FR expression. Similarly, we observed reactive microglia around FR expressing cells. However, we found that the numbers of NeuN+ neurons were conserved close to the injection site, indicating that there was little or no neuronal loss. In control mice, injected with saline only, astrocytosis and microgliosis was limited to the immediate vicinity of the injection site. Injections of opsin negative viral constructs resulted in comparable levels of astrocytic reaction as seen with opsin positive constructs. Discussion We conclude that introduction of an AAV8 vector transducing expression of a transgene under a neuron specific promotor evokes a mild inflammatory reaction in cortical tissue without causing extensive short-term neuronal loss. The expression of an opsin in addition to a fluorescent protein does not significantly increase neuroinflammation.
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Affiliation(s)
- Faye McLeod
- Centre for Transformative Neuroscience, Newcastle University Biosciences Institute, Newcastle upon Tyne, United Kingdom
| | | | | | | | | | | | | | | | - Gavin J. Clowry
- Centre for Transformative Neuroscience, Newcastle University Biosciences Institute, Newcastle upon Tyne, United Kingdom
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Alhesain M, Ronan H, LeBeau FEN, Clowry GJ. Expression of the schizophrenia associated gene FEZ1 in the early developing fetal human forebrain. Front Neurosci 2023; 17:1249973. [PMID: 37746155 PMCID: PMC10514365 DOI: 10.3389/fnins.2023.1249973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/15/2023] [Indexed: 09/26/2023] Open
Abstract
Introduction The protein fasciculation and elongation zeta-1 (FEZ1) is involved in axon outgrowth but potentially interacts with various proteins with roles ranging from intracellular transport to transcription regulation. Gene association and other studies have identified FEZ1 as being directly, or indirectly, implicated in schizophrenia susceptibility. To explore potential roles in normal early human forebrain neurodevelopment, we mapped FEZ1 expression by region and cell type. Methods All tissues were provided with maternal consent and ethical approval by the Human Developmental Biology Resource. RNAseq data were obtained from previously published sources. Thin paraffin sections from 8 to 21 post-conceptional weeks (PCW) samples were used for RNAScope in situ hybridization and immunohistochemistry against FEZ1 mRNA and protein, and other marker proteins. Results Tissue RNAseq revealed that FEZ1 is highly expressed in the human cerebral cortex between 7.5-17 PCW and single cell RNAseq at 17-18 PCW confirmed its expression in all neuroectoderm derived cells. The highest levels were found in more mature glutamatergic neurons, the lowest in GABAergic neurons and dividing progenitors. In the thalamus, single cell RNAseq similarly confirmed expression in multiple cell types. In cerebral cortex sections at 8-10 PCW, strong expression of mRNA and protein appeared confined to post-mitotic neurons, with low expression seen in progenitor zones. Protein expression was observed in some axon tracts by 16-19 PCW. However, in sub-cortical regions, FEZ1 was highly expressed in progenitor zones at early developmental stages, showing lower expression in post-mitotic cells. Discussion FEZ1 has different expression patterns and potentially diverse functions in discrete forebrain regions during prenatal human development.
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Affiliation(s)
| | | | | | - Gavin J. Clowry
- Centre for Transformative Research in Neuroscience, Newcastle University Biosciences Institute, Newcastle upon Tyne, United Kingdom
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Zaaimi B, Turnbull M, Hazra A, Wang Y, Gandara C, McLeod F, McDermott EE, Escobedo-Cousin E, Idil AS, Bailey RG, Tardio S, Patel A, Ponon N, Gausden J, Walsh D, Hutchings F, Kaiser M, Cunningham MO, Clowry GJ, LeBeau FEN, Constandinou TG, Baker SN, Donaldson N, Degenaar P, O'Neill A, Trevelyan AJ, Jackson A. Closed-loop optogenetic control of the dynamics of neural activity in non-human primates. Nat Biomed Eng 2023; 7:559-575. [PMID: 36266536 PMCID: PMC7614485 DOI: 10.1038/s41551-022-00945-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 08/14/2022] [Indexed: 11/08/2022]
Abstract
Electrical neurostimulation is effective in the treatment of neurological disorders, but associated recording artefacts generally limit its applications to open-loop stimuli. Real-time and continuous closed-loop control of brain activity can, however, be achieved by pairing concurrent electrical recordings and optogenetics. Here we show that closed-loop optogenetic stimulation with excitatory opsins enables the precise manipulation of neural dynamics in brain slices from transgenic mice and in anaesthetized non-human primates. The approach generates oscillations in quiescent tissue, enhances or suppresses endogenous patterns in active tissue and modulates seizure-like bursts elicited by the convulsant 4-aminopyridine. A nonlinear model of the phase-dependent effects of optical stimulation reproduced the modulation of cycles of local-field potentials associated with seizure oscillations, as evidenced by the systematic changes in the variability and entropy of the phase-space trajectories of seizures, which correlated with changes in their duration and intensity. We also show that closed-loop optogenetic neurostimulation could be delivered using intracortical optrodes incorporating light-emitting diodes. Closed-loop optogenetic approaches may be translatable to therapeutic applications in humans.
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Affiliation(s)
- B Zaaimi
- Biosciences Institute, Newcastle University, Newcastle, UK
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - M Turnbull
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - A Hazra
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Y Wang
- School of Computing, Newcastle University, Newcastle, UK
| | - C Gandara
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - F McLeod
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - E E McDermott
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - A Shah Idil
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - R G Bailey
- School of Engineering, Newcastle University, Newcastle, UK
| | - S Tardio
- School of Engineering, Newcastle University, Newcastle, UK
| | - A Patel
- School of Engineering, Newcastle University, Newcastle, UK
| | - N Ponon
- School of Engineering, Newcastle University, Newcastle, UK
| | - J Gausden
- School of Engineering, Newcastle University, Newcastle, UK
| | - D Walsh
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - F Hutchings
- School of Computing, Newcastle University, Newcastle, UK
| | - M Kaiser
- School of Computing, Newcastle University, Newcastle, UK
- NIHR, Nottingham Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - M O Cunningham
- School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - G J Clowry
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - F E N LeBeau
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - T G Constandinou
- Department of Electrical and Electronic Engineering, Imperial College, London, UK
| | - S N Baker
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - N Donaldson
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - P Degenaar
- School of Engineering, Newcastle University, Newcastle, UK
| | - A O'Neill
- School of Engineering, Newcastle University, Newcastle, UK
| | - A J Trevelyan
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - A Jackson
- Biosciences Institute, Newcastle University, Newcastle, UK.
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5
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McLeod F, Dimtsi A, Marshall AC, Lewis-Smith D, Thomas R, Clowry GJ, Trevelyan AJ. Altered synaptic connectivity in an in vitro human model of STXBP1 encephalopathy. Brain 2023; 146:850-857. [PMID: 36315647 PMCID: PMC9976961 DOI: 10.1093/brain/awac396] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 08/05/2022] [Accepted: 10/01/2022] [Indexed: 01/14/2023] Open
Abstract
Early infantile developmental and epileptic encephalopathies are devastating conditions, generally of genetic origin, but the pathological mechanisms often remain obscure. A major obstacle in this field of research is the difficulty of studying cortical brain development in humans, at the relevant time period in utero. To address this, we established an in vitro assay to study the impact of gene variants on the developing human brain by using living organotypic cultures of the human subplate and neighbouring cortical regions, prepared from ethically sourced, 14-17 post-conception week brain tissue (www.hdbr.org). We were able to maintain cultures for several months, during which time the gross anatomical structures of the cortical plate, subplate and marginal zone persisted, while neurons continued to develop morphologically and form new synaptic networks. This preparation thus permits the study of genetic manipulations and their downstream effects on an intact developing human cortical network. We focused on STXBP1 haploinsufficiency, which is among the most common genetic causes of developmental and epileptic encephalopathy. This was induced using shRNA interference, leading to impaired synaptic function and a reduced density of glutamatergic synapses. We thereby provide a critical proof-of-principle for how to study the impact of any gene of interest on the development of the human cortex.
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Affiliation(s)
- Faye McLeod
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Anna Dimtsi
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Amy C Marshall
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David Lewis-Smith
- Newcastle University Translational and Clinical Research Institute, Newcastle upon Tyne NE2 4HH, UK
- Department of Clinical Neurosciences, Royal Victoria Infirmary, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Rhys Thomas
- Newcastle University Translational and Clinical Research Institute, Newcastle upon Tyne NE2 4HH, UK
- Department of Clinical Neurosciences, Royal Victoria Infirmary, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew J Trevelyan
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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6
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Alzu'bi A, Sankar N, Crosier M, Kerwin J, Clowry GJ. Tyramide signal amplification coupled with multiple immunolabeling and RNAScope in situ hybridization in formaldehyde-fixed paraffin-embedded human fetal brain. J Anat 2022; 241:33-41. [PMID: 35224745 PMCID: PMC9178390 DOI: 10.1111/joa.13644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/28/2022] Open
Abstract
Several strategies have been recently introduced to improve the practicality of multiple immunolabeling and RNA in situ hybridization protocols. Tyramide signal amplification (TSA) is a powerful method used to improve the detection sensitivity of immunohistochemistry. RNAScope is a novel commercially available in situ hybridization assay for the detection of RNA expression. In this work, we describe the use of TSA and RNAScope in situ hybridization as extremely sensitive and specific methods for the evaluation of protein and RNA expression in formaldehyde-fixed paraffin-embedded human fetal brain sections. These two techniques, when properly optimized, were highly compatible with routine formaldehyde-fixed paraffin-embedded tissue that preserves the best morphological characteristics of delicate fetal brain samples, enabling an unparalleled ability to simultaneously visualize the expression of multiple protein and mRNA of genes that are sparsely expressed in the human fetal telencephalon.
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Affiliation(s)
- Ayman Alzu'bi
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.,Department of Basic Medical Sciences, Yarmouk University, Irbid, Jordan
| | - Niveditha Sankar
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Moira Crosier
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.,Human Developmental Biology Resource, Newcastle University, Newcastle upon Tyne, UK
| | - Janet Kerwin
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.,Human Developmental Biology Resource, Newcastle University, Newcastle upon Tyne, UK
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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7
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Alzu'bi A, Al Zoubi MS, Abdelhady GT, Al-Trad B, Omari S, Abualarjah MI, El-Huneidi W, Alzu'bi DR, Bani-Issa JM, Clowry GJ. Reduced placental size and increased apoptosis are associated with prenatal nicotine exposure in rats. Eur Rev Med Pharmacol Sci 2022; 26:1586-1593. [PMID: 35302204 DOI: 10.26355/eurrev_202203_28225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
OBJECTIVE Smoking during pregnancy has been linked to a variety of negative embryonic and neonatal consequences. Nicotine is the major constituent of tobacco smoke, which was associated with adverse impacts on histological and functional features of the placenta. This study aims to investigate the potential influence of nicotine exposure on the rat placenta and fetus. MATERIALS AND METHODS Nicotine was administrated through the drinking water of female pregnant rats. The placental size, as well as the fetal body weight and size, were measured at E20. The mRNA expression of the Bax gene (pro-apoptotic), the Bcl-2 gene (anti-apoptotic) and the angiogenic genes VEGF, Flt-1, and HIF1 were measured in placental tissue. Furthermore, Immunohistochemistry (IHC) using Bax, caspase 9 and VEGF antibodies were performed on placental sections. RESULTS The results of the current study showed a significant reduction in the size of the placenta along with fetal body weight in nicotine treated group compared to the control group. Apoptosis was observed to be boosted in the placentas of the nicotine-treated group. This was associated with upregulation of Bax expression combined with no change in the expression of Bcl-2 in the treated group. On the other hand, there was no difference in the expression of angiogenic factors VEGF, Flt-1, or HIF1 between tested groups. CONCLUSIONS In utero nicotine exposure in pregnant rats showed deleterious impacts on fetus growth and weight, as well as placental size. These were accompanied by increased apoptosis within the placenta, as revealed by Bax gene upregulation.
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Affiliation(s)
- A Alzu'bi
- Department of Basic Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, Jordan.
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8
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Bauer R, Clowry GJ, Kaiser M. Creative Destruction: A Basic Computational Model of Cortical Layer Formation. Cereb Cortex 2021; 31:3237-3253. [PMID: 33625496 PMCID: PMC8196252 DOI: 10.1093/cercor/bhab003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/13/2022] Open
Abstract
One of the most characteristic properties of many vertebrate neural systems is the layered organization of different cell types. This cytoarchitecture exists in the cortex, the retina, the hippocampus, and many other parts of the central nervous system. The developmental mechanisms of neural layer formation have been subject to substantial experimental efforts. Here, we provide a general computational model for cortical layer formation in 3D physical space. We show that this multiscale, agent-based model, comprising two distinct stages of apoptosis, can account for the wide range of neuronal numbers encountered in different cortical areas and species. Our results demonstrate the phenotypic richness of a basic state diagram structure. Importantly, apoptosis allows for changing the thickness of one layer without automatically affecting other layers. Therefore, apoptosis increases the flexibility for evolutionary change in layer architecture. Notably, slightly changed gene regulatory dynamics recapitulate the characteristic properties observed in neurodevelopmental diseases. Overall, we propose a novel computational model using gene-type rules, exhibiting many characteristics of normal and pathological cortical development.
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Affiliation(s)
- Roman Bauer
- Department of Computer Science, University of Surrey, Guildford, GU2 7XH, UK
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Marcus Kaiser
- School of Computing, Newcastle University, Newcastle upon Tyne NE4 5TG, UK
- Precision Imaging Beacon, School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
- Rui Jin Hospital, Shanghai Jiao Tong University, Shanghai 200025, China
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Hayman DJ, Modebadze T, Charlton S, Cheung K, Soul J, Lin H, Hao Y, Miles CG, Tsompani D, Jackson RM, Briggs MD, Piróg KA, Clark IM, Barter MJ, Clowry GJ, LeBeau FEN, Young DA. Increased hippocampal excitability in miR-324-null mice. Sci Rep 2021; 11:10452. [PMID: 34001919 PMCID: PMC8129095 DOI: 10.1038/s41598-021-89874-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 04/30/2021] [Indexed: 12/31/2022] Open
Abstract
MicroRNAs are non-coding RNAs that act to downregulate the expression of target genes by translational repression and degradation of messenger RNA molecules. Individual microRNAs have the ability to specifically target a wide array of gene transcripts, therefore allowing each microRNA to play key roles in multiple biological pathways. miR-324 is a microRNA predicted to target thousands of RNA transcripts and is expressed far more highly in the brain than in any other tissue, suggesting that it may play a role in one or multiple neurological pathways. Here we present data from the first global miR-324-null mice, in which increased excitability and interictal discharges were identified in vitro in the hippocampus. RNA sequencing was used to identify differentially expressed genes in miR-324-null mice which may contribute to this increased hippocampal excitability, and 3'UTR luciferase assays and western blotting revealed that two of these, Suox and Cd300lf, are novel direct targets of miR-324. Characterisation of microRNAs that produce an effect on neurological activity, such as miR-324, and identification of the pathways they regulate will allow a better understanding of the processes involved in normal neurological function and in turn may present novel pharmaceutical targets in treating neurological disease.
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Affiliation(s)
- Dan J Hayman
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Tamara Modebadze
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Sarah Charlton
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Kat Cheung
- Bioinformatics Support Unit, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Jamie Soul
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Hua Lin
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Yao Hao
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
- Orthopedics Department, First Hospital of Shanxi Medical University, Yingze District, Taiyuan, 030000, China
| | - Colin G Miles
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Dimitra Tsompani
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Robert M Jackson
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Michael D Briggs
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Katarzyna A Piróg
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Ian M Clark
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Matt J Barter
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Fiona E N LeBeau
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - David A Young
- Biosciences Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
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Tweedy C, Kindred N, Curry J, Williams C, Taylor JP, Atkinson P, Randall F, Erskine D, Morris CM, Reeve AK, Clowry GJ, LeBeau FEN. Hippocampal network hyperexcitability in young transgenic mice expressing human mutant alpha-synuclein. Neurobiol Dis 2020; 149:105226. [PMID: 33347975 PMCID: PMC7859835 DOI: 10.1016/j.nbd.2020.105226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 11/12/2020] [Accepted: 12/16/2020] [Indexed: 02/07/2023] Open
Abstract
Abnormal excitability in cortical networks has been reported in patients and animal models of Alzheimer's disease (AD), and other neurodegenerative conditions. Whether hyperexcitability is a core feature of alpha(α)-synucleinopathies, including dementia with Lewy bodies (DLB) is unclear. To assess this, we used two murine models of DLB that express either human mutant α-synuclein (α-syn) the hA30P, or human wild-type α-syn (hWT-α-syn) mice. We observed network hyperexcitability in vitro in young (2–5 months), pre-symptomatic transgenic α-syn mice. Interictal discharges (IIDs) were seen in the extracellular local field potential (LFP) in the hippocampus in hA30P and hWT-α-syn mice following kainate application, while only gamma frequency oscillations occurred in control mice. In addition, the concentration of the GABAA receptor antagonist (gabazine) needed to evoke IIDs was lower in slices from hA30P mice compared to control mice. hA30P mice also showed increased locomotor activity in the open field test compared to control mice. Intracellular recordings from CA3 pyramidal cells showed a more depolarised resting membrane potential in hA30P mice. Quadruple immunohistochemistry for human α-syn, and the mitochondrial markers, porin and the complex IV enzyme cytochrome c oxidase subunit 1 (COX1) in parvalbumin (PV+)-expressing interneurons showed that 25% of PV+ cells contained human α-syn in hA30P mice. While there was no change in PV expression, COX1 expression was significantly increased in PV+ cells in hA30P mice, perhaps reflecting a compensatory change to support PV+ interneuron activity. Our findings suggest that hippocampal network hyperexcitability may be an important early consequence of α-syn-mediated impairment of neuronal/synaptic function, which occurs without any overt loss of PV interneurons. The therapeutic benefit of targeting network excitability early in the disease stage should be explored with respect to α-synucleinopathies such as DLB. Young transgenic α-syn mice exhibit network hyperexcitability in the hippocampus in vitro. Young transgenic α-syn mice have increased locomotor activity in an open field test. Hippocampal pyramidal cells are more depolarised in young transgenic α-syn mice. Increased mitochondrial cytochrome c oxidase (complex IV) function in PV+ interneurons in young transgenic a-syn mice.
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Affiliation(s)
- Clare Tweedy
- Biosciences Institute, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Nathan Kindred
- Biosciences Institute, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Joshua Curry
- Biosciences Institute, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Christopher Williams
- Biosciences Institute, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - John-Paul Taylor
- Institute of Clinical and Translational Research, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Peter Atkinson
- Eisai Hatfield Research Laboratories, Eisai Ltd., European Knowledge Centre, Mosquito Way, Hatfield, Herts AL10 9SN, UK
| | - Fiona Randall
- Previously Eisai AiM Institute, Eisai Inc., 4 Corporate Drive, Andover, MA 01810, USA
| | - Daniel Erskine
- Institute of Clinical and Translational Research, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Christopheer M Morris
- Institute of Clinical and Translational Research, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Amy K Reeve
- Institute of Clinical and Translational Research, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Fiona E N LeBeau
- Biosciences Institute, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK.
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11
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Powell L, Barroso-Gil M, Clowry GJ, Devlin LA, Molinari E, Ramsbottom SA, Miles CG, Sayer JA. Expression patterns of ciliopathy genes ARL3 and CEP120 reveal roles in multisystem development. BMC Dev Biol 2020; 20:26. [PMID: 33297941 PMCID: PMC7727171 DOI: 10.1186/s12861-020-00231-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/11/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Joubert syndrome and related disorders (JSRD) and Jeune syndrome are multisystem ciliopathy disorders with overlapping phenotypes. There are a growing number of genetic causes for these rare syndromes, including the recently described genes ARL3 and CEP120. METHODS We sought to explore the developmental expression patterns of ARL3 and CEP120 in humans to gain additional understanding of these genetic conditions. We used an RNA in situ detection technique called RNAscope to characterise ARL3 and CEP120 expression patterns in human embryos and foetuses in collaboration with the MRC-Wellcome Trust Human Developmental Biology Resource. RESULTS Both ARL3 and CEP120 are expressed in early human brain development, including the cerebellum and in the developing retina and kidney, consistent with the clinical phenotypes seen with pathogenic variants in these genes. CONCLUSIONS This study provides insights into the potential pathogenesis of JSRD by uncovering the spatial expression of two JSRD-causative genes during normal human development.
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Affiliation(s)
- L Powell
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - M Barroso-Gil
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - G J Clowry
- Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - L A Devlin
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - E Molinari
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - S A Ramsbottom
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - C G Miles
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - J A Sayer
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
- The Newcastle Hospitals NHS Foundation Trust, Freeman Road, Newcastle upon Tyne, NE7 7DN, UK.
- National Institute for Health Research Newcastle Biomedical Research Centre, Newcastle upon Tyne, NE4 5PL, UK.
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12
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Alzu'bi A, Clowry GJ. Multiple Origins of Secretagogin Expressing Cortical GABAergic Neuron Precursors in the Early Human Fetal Telencephalon. Front Neuroanat 2020; 14:61. [PMID: 32982702 PMCID: PMC7492523 DOI: 10.3389/fnana.2020.00061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/10/2020] [Indexed: 01/31/2023] Open
Abstract
Secretagogin (SCGN) which acts as a calcium signaling sensor, has previously been shown to be expressed by a substantial population of cortical GABAergic neurons at mid-gestation in humans but not in mice. The present study traced SCGN expression in cortical GABAergic neurons in human fetal forebrain from earlier stages than previously studied. Multiple potential origins of SCGN-expressing neurons were identified in the caudal ganglionic eminence (CGE) lateral ganglionic eminence (LGE) septum and preoptic area; these cells largely co-expressed SP8 but not the medial ganglionic eminence marker LHX6. They followed various migration routes to reach their target regions in the neocortex, insular and olfactory cortex (OC) and olfactory bulbs. A robust increase in the number of SCGN-expressing GABAergic cortical neurons was observed in the midgestational period; 58% of DLX2+ neurons expressed SCGN in the cortical wall at 19 post-conceptional weeks (PCW), a higher proportion than expressed calretinin, a marker for GABAergic neurons of LGE/CGE origin. Furthermore, although most SCGN+ neurons co-expressed calretinin in the cortical plate (CP) and deeper layers, in the marginal zone (MZ) SCGN+ and calretinin+ cells formed separate populations. In the adult mouse, it has previously been shown that in the rostral migratory stream (RMS), SCGN, annexin V (ANXA5), and matrix metalloprotease 2 (MMP2) are co-expressed forming a functioning complex that exocytoses MMP2 in response to calcium. In the present study, ANXA5 showed widespread expression throughout the cortical wall, although MMP2 expression was very largely limited to the CP. We found co-expression of these proteins in some SCGN+ neurons in the subventricular zones (SVZ) suggesting a limited role for these cells in remodeling the extracellular matrix, perhaps during cell migration.
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Affiliation(s)
- Ayman Alzu'bi
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.,Department of Basic Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, Jordan
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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13
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Alzu'bi A, Middleham W, Shoaib M, Clowry GJ. Selective Expression of Nicotinic Receptor Sub-unit mRNA in Early Human Fetal Forebrain. Front Mol Neurosci 2020; 13:72. [PMID: 32670017 PMCID: PMC7326072 DOI: 10.3389/fnmol.2020.00072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/14/2020] [Indexed: 12/22/2022] Open
Abstract
Increasing evidence from animal and human studies indicate that exposure to nicotine during development, separated from the effects of smoking tobacco, can contribute to dysregulation of brain development including behavioral deficits. An RNAseq study of human fetal cerebral cortex demonstrated that 9 out of 16 genes for human nicotinic acetylcholine (ACh) receptor subunits are selectively expressed between 7.5 and 12 post-conceptional weeks (PCW). The most highly expressed subunit genes were CHNRA4 and CHNRB2, whose protein products combine to form the most ubiquitous functional receptor isoform expressed in the adult brain. They exhibited correlated expression in both RNAseq samples, and in tissue sections by in situ hybridization. Co-localization studies with other cortical markers suggest they are pre-dominantly expressed by post-mitotic glutamatergic neuron pre-cursors in both cortical plate and pre-subplate, rather than cortical progenitor cells or GABAergic interneuron pre-cursors. However, GABAergic interneuron progenitor cells in the ganglionic eminences do express these sub-units. CHNRA5 also showed moderate levels of expression and again favored post-mitotic neurons. Other subunits, e.g., CHRNA7, exhibited low but detectable levels of expression. CHRN genes found not to be expressed included genes for subunits usually considered muscle specific, e.g., CHNRA1, although some muscle specific gene expression was detected, for instance CHNRB1. Although there is little or no synthesis of acetylcholine by intrinsic cortical neurons, cholinergic fibers from basal forebrain innervate the cerebral cortex from 12 PCW at the latest. Acetylcholine may have a paracrine effect on radially migrating cortical neurons and GABAergic interneuron progenitors.
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Affiliation(s)
- Ayman Alzu'bi
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.,Department of Basic Medical Sciences, Yarmouk University, Irbid, Jordan
| | - William Middleham
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mohammed Shoaib
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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14
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Molnár Z, Clowry GJ, Šestan N, Alzu'bi A, Bakken T, Hevner RF, Hüppi PS, Kostović I, Rakic P, Anton ES, Edwards D, Garcez P, Hoerder‐Suabedissen A, Kriegstein A. New insights into the development of the human cerebral cortex. J Anat 2019; 235:432-451. [PMID: 31373394 PMCID: PMC6704245 DOI: 10.1111/joa.13055] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2019] [Indexed: 12/12/2022] Open
Abstract
The cerebral cortex constitutes more than half the volume of the human brain and is presumed to be responsible for the neuronal computations underlying complex phenomena, such as perception, thought, language, attention, episodic memory and voluntary movement. Rodent models are extremely valuable for the investigation of brain development, but cannot provide insight into aspects that are unique or highly derived in humans. Many human psychiatric and neurological conditions have developmental origins but cannot be studied adequately in animal models. The human cerebral cortex has some unique genetic, molecular, cellular and anatomical features, which need to be further explored. The Anatomical Society devoted its summer meeting to the topic of Human Brain Development in June 2018 to tackle these important issues. The meeting was organized by Gavin Clowry (Newcastle University) and Zoltán Molnár (University of Oxford), and held at St John's College, Oxford. The participants provided a broad overview of the structure of the human brain in the context of scaling relationships across the brains of mammals, conserved principles and recent changes in the human lineage. Speakers considered how neuronal progenitors diversified in human to generate an increasing variety of cortical neurons. The formation of the earliest cortical circuits of the earliest generated neurons in the subplate was discussed together with their involvement in neurodevelopmental pathologies. Gene expression networks and susceptibility genes associated to neurodevelopmental diseases were discussed and compared with the networks that can be identified in organoids developed from induced pluripotent stem cells that recapitulate some aspects of in vivo development. New views were discussed on the specification of glutamatergic pyramidal and γ-aminobutyric acid (GABA)ergic interneurons. With the advancement of various in vivo imaging methods, the histopathological observations can be now linked to in vivo normal conditions and to various diseases. Our review gives a general evaluation of the exciting new developments in these areas. The human cortex has a much enlarged association cortex with greater interconnectivity of cortical areas with each other and with an expanded thalamus. The human cortex has relative enlargement of the upper layers, enhanced diversity and function of inhibitory interneurons and a highly expanded transient subplate layer during development. Here we highlight recent studies that address how these differences emerge during development focusing on diverse facets of our evolution.
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Affiliation(s)
- Zoltán Molnár
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
| | - Gavin J. Clowry
- Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Nenad Šestan
- Department of Neuroscience, Yale University School of MedicineNew HavenCTUSA
| | - Ayman Alzu'bi
- Department of Basic Medical SciencesFaculty of MedicineYarmouk UniversityIrbidJordan
| | | | | | - Petra S. Hüppi
- Dept. de l'enfant et de l'adolescentHôpitaux Universitaires de GenèveGenèveSwitzerland
| | - Ivica Kostović
- Croatian Institute for Brain ResearchSchool of MedicineUniversity of ZagrebZagrebCroatia
| | - Pasko Rakic
- Department of Neuroscience, Yale University School of MedicineNew HavenCTUSA
| | - E. S. Anton
- UNC Neuroscience CenterDepartment of Cell and Molecular PhysiologyThe University of North Carolina School of MedicineChapel HillNCUSA
| | - David Edwards
- Centre for the Developing BrainBiomedical Engineering and Imaging Sciences,King's College LondonLondonUK
| | - Patricia Garcez
- Federal University of Rio de Janeiro, UFRJInstitute of Biomedical SciencesRio de JaneiroBrazil
| | | | - Arnold Kriegstein
- Department of NeurologyUniversity of California, San Francisco (UCSF)San FranciscoCAUSA
- The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUCSFSan FranciscoCAUSA
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15
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Alzu'bi A, Homman-Ludiye J, Bourne JA, Clowry GJ. Corrigendum: Thalamocortical Afferents Innervate the Cortical Subplate much Earlier in Development in Primate than in Rodent. Cereb Cortex 2019; 29:5316. [PMID: 31037284 PMCID: PMC6918923 DOI: 10.1093/cercor/bhz056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Indexed: 12/04/2022] Open
Affiliation(s)
- Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.,Department of Basic Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, 11263, Jordan
| | - Jihane Homman-Ludiye
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - James A Bourne
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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16
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Alzu’bi A, Homman-Ludiye J, Bourne JA, Clowry GJ. Thalamocortical Afferents Innervate the Cortical Subplate much Earlier in Development in Primate than in Rodent. Cereb Cortex 2019; 29:1706-1718. [PMID: 30668846 PMCID: PMC6418397 DOI: 10.1093/cercor/bhy327] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/16/2018] [Accepted: 11/29/2018] [Indexed: 12/21/2022] Open
Abstract
The current model, based on rodent data, proposes that thalamocortical afferents (TCA) innervate the subplate towards the end of cortical neurogenesis. This implies that the laminar identity of cortical neurons is specified by intrinsic instructions rather than information of thalamic origin. In order to determine whether this mechanism is conserved in the primates, we examined the growth of thalamocortical (TCA) and corticofugal afferents in early human and monkey fetal development. In the human, TCA, identified by secretagogin, calbindin, and ROBO1 immunoreactivity, were observed in the internal capsule of the ventral telencephalon as early as 7-7.5 PCW, crossing the pallial/subpallial boundary (PSB) by 8 PCW before the calretinin immunoreactive corticofugal fibers do. Furthermore, TCA were observed to be passing through the intermediate zone and innervating the presubplate of the dorsolateral cortex, and already by 10-12 PCW TCAs were occupying much of the cortex. Observations at equivalent stages in the marmoset confirmed that this pattern is conserved across primates. Therefore, our results demonstrate that in primates, TCAs innervate the cortical presubplate at earlier stages than previously demonstrated by acetylcholinesterase histochemistry, suggesting that pioneer thalamic afferents may contribute to early cortical circuitry that can participate in defining cortical neuron phenotypes.
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Affiliation(s)
- Ayman Alzu’bi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Department of Basic Medical Sciences, Faculty of Medicine, Yarmouk University, Irbid, Jordan
| | - Jihane Homman-Ludiye
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - James A Bourne
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
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17
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Alzu'bi A, Clowry GJ. Expression of ventral telencephalon transcription factors ASCL1 and DLX2 in the early fetal human cerebral cortex. J Anat 2019; 235:555-568. [PMID: 30861584 PMCID: PMC6704271 DOI: 10.1111/joa.12971] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2019] [Indexed: 01/21/2023] Open
Abstract
In rodent ventral telencephalon, diffusible morphogens induce expression of the proneural transcription factor ASCL1, which in turn induces expression of the transcription factor DLX2 that controls differentiation of cortical interneuron precursors and their tangential migration to the cerebral cortex. RNAseq analysis of human fetal samples of dorsal telencephalon revealed consistently high cortical expression of ASCL1 and increasing expression of DLX2 between 7.5 and 17 post‐conceptional weeks (PCW). We explored whether cortical expression of these genes represented a population of intracortically derived interneuron precursors. Immunohistochemistry revealed an ASCL1+/DLX2+ population of progenitor cells in the human ganglionic eminences between 6.5 and 12 PCW, but in the cortex there also existed a population of ASCL1+/DLX2– progenitors in the subventricular zone (SVZ) that largely co‐expressed cortical markers PAX6 or TBR2, although a few ASCL1+/PAX6– progenitors were observed in the ventricular zone (VZ) and ASCL1+ cells expressing the interneuron marker GAD67 were present in the SVZ. Although rare in the VZ, DLX2+ cells progressively increased in number between 8 and 12 PCW across the cortical wall and the majority co‐expressed LHX6 and originated either in the MGE, migrating to the lateral cortex, or from the septum, populating the medial wall. A minority co‐expressed COUP‐TFII, which identifies cells from the caudal ganglionic eminence (CGE). By 19 PCW, a significant increase in expression of DLX2 and ASCL1 was observed in the cortical VZ with a small proportion expressing both proteins. The DLX2+ cells did not co‐express a cell division marker, so were not progenitors. The majority of DLX2+ cells throughout the cortical plate expressed COUP‐TFII rather than LHX6+. As the VZ declined as a proliferative zone it appeared to be re‐defined as a migration pathway for COUP‐TFII+/DLX2+ interneurons from CGE to cortex. Therefore, in developing human cortex, ASCL1 expression predominantly marks a population of intermediate progenitors giving rise to glutamatergic neurons. DLX2 expression predominantly defines post‐mitotic interneuron precursors.
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Affiliation(s)
- Ayman Alzu'bi
- The institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,The Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,The Department of Basic Medical Sciences, Yarmouk University, Irbid, Jordan
| | - Gavin J Clowry
- The institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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18
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Harkin LF, Lindsay SJ, Xu Y, Alzu'bi A, Ferrera A, Gullon EA, James OG, Clowry GJ. Corrigendum: Neurexins 1-3 Each Have a Distinct Pattern of Expression in the Early Developing Human Cerebral Cortex. Cereb Cortex 2019; 29:1705. [PMID: 30753338 DOI: 10.1093/cercor/bhz012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Lauren F Harkin
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Susan J Lindsay
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Alexandra Ferrera
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Emily A Gullon
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Owen G James
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
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19
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Basuodan R, Basu AP, Clowry GJ. Human neural stem cells dispersed in artificial ECM form cerebral organoids when grafted in vivo. J Anat 2018; 233:155-166. [PMID: 29745426 DOI: 10.1111/joa.12827] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2018] [Indexed: 12/11/2022] Open
Abstract
Human neural stem cells (hNSC) derived from induced pluripotent stem cells can be differentiated into neurons that could be used for transplantation to repair brain injury. In this study we dispersed such hNSC in a three-dimensional artificial extracellular matrix (aECM) and compared their differentiation in vitro and following grafting into the sensorimotor cortex (SMC) of postnatal day (P)14 rat pups lesioned by localised injection of endothelin-1 at P12. After 10-43 days of in vitro differentiation, a few cells remained as PAX6+ neuroprogenitors but many more resembled post-mitotic neurons expressing doublecortin, β-tubulin and MAP2. These cells remained dispersed throughout the ECM, but with extended long processes for over 50 μm. In vivo, by 1 month post grafting, cells expressing human specific markers instead organised into cerebral organoids: columns of tightly packed PAX6 co-expressing progenitor cells arranged around small tubular lumen in rosettes, with a looser network of cells with processes around the outside co-expressing markers of immature neurons including doublecortin, and CTIP2 characteristic of corticofugal neurons. Host cells also invaded the graft including microglia, astrocytes and endothelial cells forming blood vessels. By 10 weeks post-grafting, the organoids had disappeared and the aECM had started to break down with fewer transplanted cells remaining. In vitro, cerebral organoids form in rotating incubators that force oxygen and nutrients to the centre of the structures. We have shown that cerebral organoids can form in vivo; intrinsic factors may direct their organisation including infiltration by host blood vessels.
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Affiliation(s)
- Reem Basuodan
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,Health and Rehabilitation Sciences, Princess Noura bint Abdulrhman University, Riyadh, Saudi Arabia
| | - Anna P Basu
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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20
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Robson E, Tweedy C, Manzanza N, Taylor JP, Atkinson P, Randall F, Reeve A, Clowry GJ, LeBeau FEN. Impaired Fast Network Oscillations and Mitochondrial Dysfunction in a Mouse Model of Alpha-synucleinopathy (A30P). Neuroscience 2018. [PMID: 29524634 DOI: 10.1016/j.neuroscience.2018.02.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Intracellular accumulation of alpha-synuclein (α-syn) is a key pathological process evident in Lewy body dementias (LBDs), including Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB). LBD results in marked cognitive impairments and changes in cortical networks. To assess the impact of abnormal α-syn expression on cortical network oscillations relevant to cognitive function, we studied changes in fast beta/gamma network oscillations in the hippocampus in a mouse line that over-expresses human mutant α-syn (A30P). We found an age-dependent reduction in the power of the gamma (20-80 Hz) frequency oscillations in slices taken from mice aged 9-16 months (9+A30P), that was not present in either young 2-6 months old (2+A30P) mice, or in control mice at either age. The mitochondrial blockers potassium cyanide and rotenone both reduced network oscillations in a concentration-dependent manner in aged A30P mice and aged control mice but slices from A30P mice showed a greater reduction in the oscillations. Histochemical analysis showed an age-dependent reduction in cytochrome c oxidase (COX) activity, suggesting a mitochondrial dysfunction in the 9+A30P group. A deficit in COX IV expression was confirmed by immunohistochemistry. Overall, our data demonstrate an age-dependent impairment in mitochondrial function and gamma frequency activity associated with the abnormal expression of α-syn. These findings provide mechanistic insights into the consequences of over-expression of α-syn which might contribute to cognitive decline.
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Affiliation(s)
- Emma Robson
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Clare Tweedy
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Nelson Manzanza
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - John-Paul Taylor
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Peter Atkinson
- Eisai Hatfield Research Laboratories, Eisai Ltd., European Knowledge Centre, Mosquito Way, Hatfield, Herts AL10 9SN, UK
| | - Fiona Randall
- Eisai AiM Institute, Eisai Inc., 4 Corporate Drive, Andover, MA 01810, USA
| | - Amy Reeve
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Fiona E N LeBeau
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK.
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21
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Ehrmann I, Gazzara MR, Pagliarini V, Dalgliesh C, Kheirollahi-Chadegani M, Xu Y, Cesari E, Danilenko M, Maclennan M, Lowdon K, Vogel T, Keskivali-Bond P, Wells S, Cater H, Fort P, Santibanez-Koref M, Middei S, Sette C, Clowry GJ, Barash Y, Cunningham MO, Elliott DJ. A SLM2 Feedback Pathway Controls Cortical Network Activity and Mouse Behavior. Cell Rep 2017; 17:3269-3280. [PMID: 28009295 PMCID: PMC5199341 DOI: 10.1016/j.celrep.2016.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 10/25/2016] [Accepted: 11/29/2016] [Indexed: 02/07/2023] Open
Abstract
The brain is made up of trillions of synaptic connections that together form neural networks needed for normal brain function and behavior. SLM2 is a member of a conserved family of RNA binding proteins, including Sam68 and SLM1, that control splicing of Neurexin1-3 pre-mRNAs. Whether SLM2 affects neural network activity is unknown. Here, we find that SLM2 levels are maintained by a homeostatic feedback control pathway that predates the divergence of SLM2 and Sam68. SLM2 also controls the splicing of Tomosyn2, LysoPLD/ATX, Dgkb, Kif21a, and Cask, each of which are important for synapse function. Cortical neural network activity dependent on synaptic connections between SLM2-expressing-pyramidal neurons and interneurons is decreased in Slm2-null mice. Additionally, these mice are anxious and have a decreased ability to recognize novel objects. Our data reveal a pathway of SLM2 homeostatic auto-regulation controlling brain network activity and behavior. SLM2 splicing targets are spatially controlled within the hippocampus RNA-seq reveals SLM2 feedback control and synaptic protein splicing targets Loss of SLM2 dampens patterns of hippocampal γ oscillations Loss of SLM2 changes mouse behavior that depends on these neural networks
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Affiliation(s)
- Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Matthew R Gazzara
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vittoria Pagliarini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome and Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | | | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Eleonora Cesari
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome and Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Marina Danilenko
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Marie Maclennan
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Kate Lowdon
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Tanja Vogel
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
| | | | - Sara Wells
- Mary Lyon Centre, MRC Harwell Institute, Oxfordshire OX11 ORD, UK
| | - Heather Cater
- Mary Lyon Centre, MRC Harwell Institute, Oxfordshire OX11 ORD, UK
| | - Philippe Fort
- Université Montpellier, UMR 5237, Centre de Recherche de Biologie cellulaire de Montpellier, CNRS, Montpellier 34293, France
| | | | - Silvia Middei
- Institute of Cell Biology and Neurobiology, Consiglio Nazionale delle Ricerche, Via E. Ramarini 32, 00015 Monterotondo Scalo-Roma, Italy
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome and Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
| | - Yoseph Barash
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Computer and Information Science, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Mark O Cunningham
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.
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22
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Alzu'bi A, Lindsay SJ, Harkin LF, McIntyre J, Lisgo SN, Clowry GJ. The Transcription Factors COUP-TFI and COUP-TFII have Distinct Roles in Arealisation and GABAergic Interneuron Specification in the Early Human Fetal Telencephalon. Cereb Cortex 2017; 27:4971-4987. [PMID: 28922831 PMCID: PMC5903418 DOI: 10.1093/cercor/bhx185] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/12/2017] [Accepted: 07/03/2017] [Indexed: 12/13/2022] Open
Abstract
In human telencephalon at 8-12 postconceptional weeks, ribonucleic acid quantitative sequencing and immunohistochemistry revealed cortical chicken ovalbumin upstream promotor-transcription factor 1 (COUP-TFI) expression in a high ventro-posterior to low anterior gradient except for raised immunoreactivity in the anterior ventral pallium. Unlike in mouse, COUP-TFI and SP8 were extensively co-expressed in dorsal sensory neocortex and dorsal hippocampus whereas COUPTFI/COUPTFII co-expression defined ventral temporal cortex and ventral hippocampus. In the ganglionic eminences (GEs) COUP-TFI immunoreactivity demarcated the proliferative zones of caudal GE (CGE), dorsal medial GE (MGE), MGE/lateral GE (LGE) boundary, and ventral LGE whereas COUP-TFII was limited to ventral CGE and the MGE/LGE boundary. Co-labeling with gamma amino butyric acidergic interneuron markers revealed that COUP-TFI was expressed in subpopulations of either MGE-derived (SOX6+) or CGE-derived (calretinin+/SP8+) interneurons. COUP-TFII was mainly confined to CGE-derived interneurons. Twice as many GAD67+ cortical cells co-labeled for COUP-TFI than for COUP-TFII. A fifth of COUP-TFI cells also co-expressed COUP-TFII, and cells expressing either transcription factor followed posterior or anterio-lateral pathways into the cortex, therefore, a segregation of migration pathways according to COUP-TF expression as proposed in mouse was not observed. In cultures differentiated from isolated human cortical progenitors, many cells expressed either COUP-TF and 30% also co-expressed GABA, however no cells expressed NKX2.1. This suggests interneurons could be generated intracortically from progenitors expressing either COUP-TF.
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Affiliation(s)
- Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Susan J Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Lauren F Harkin
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
- Present address: School of Healthcare Science, Manchester Metropolitan University, UK
| | - Jack McIntyre
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Steven N Lisgo
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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23
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Danilenko M, Dalgliesh C, Pagliarini V, Naro C, Ehrmann I, Feracci M, Kheirollahi-Chadegani M, Tyson-Capper A, Clowry GJ, Fort P, Dominguez C, Sette C, Elliott DJ. Binding site density enables paralog-specific activity of SLM2 and Sam68 proteins in Neurexin2 AS4 splicing control. Nucleic Acids Res 2017; 45:4120-4130. [PMID: 27994030 PMCID: PMC5397175 DOI: 10.1093/nar/gkw1277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 12/08/2016] [Indexed: 01/09/2023] Open
Abstract
SLM2 and Sam68 are splicing regulator paralogs that usually overlap in function, yet only SLM2 and not Sam68 controls the Neurexin2 AS4 exon important for brain function. Herein we find that SLM2 and Sam68 similarly bind to Neurexin2 pre-mRNA, both within the mouse cortex and in vitro. Protein domain-swap experiments identify a region including the STAR domain that differentiates SLM2 and Sam68 activity in splicing target selection, and confirm that this is not established via the variant amino acids involved in RNA contact. However, far fewer SLM2 and Sam68 RNA binding sites flank the Neurexin2 AS4 exon, compared with those flanking the Neurexin1 and Neurexin3 AS4 exons under joint control by both Sam68 and SLM2. Doubling binding site numbers switched paralog sensitivity, by placing the Neurexin2 AS4 exon under joint splicing control by both Sam68 and SLM2. Our data support a model where the density of shared RNA binding sites around a target exon, rather than different paralog-specific protein-RNA binding sites, controls functional target specificity between SLM2 and Sam68 on the Neurexin2 AS4 exon. Similar models might explain differential control by other splicing regulators within families of paralogs with indistinguishable RNA binding sites.
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Affiliation(s)
- Marina Danilenko
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Vittoria Pagliarini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Chiara Naro
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Mikael Feracci
- Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
| | | | - Alison Tyson-Capper
- Institute for Cellular Medicine, Newcastle University, Framlington Place, Newcastle NE2 4HH, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle, UK
| | - Philippe Fort
- Université Montpellier, UMR 5237, Centre de Recherche de Biologie cellulaire de Montpellier, CNRS, 34293 Montpellier, France
| | - Cyril Dominguez
- Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
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24
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Harkin LF, Lindsay SJ, Xu Y, Alzu'bi A, Ferrara A, Gullon EA, James OG, Clowry GJ. Neurexins 1-3 Each Have a Distinct Pattern of Expression in the Early Developing Human Cerebral Cortex. Cereb Cortex 2017; 27:216-232. [PMID: 28013231 PMCID: PMC5654756 DOI: 10.1093/cercor/bhw394] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/16/2016] [Accepted: 12/02/2016] [Indexed: 12/17/2022] Open
Abstract
Neurexins (NRXNs) are presynaptic terminal proteins and candidate neurodevelopmental disorder susceptibility genes; mutations presumably upset synaptic stabilization and function. However, analysis of human cortical tissue samples by RNAseq and quantitative real-time PCR at 8-12 postconceptional weeks, prior to extensive synapse formation, showed expression of all three NRXNs as well as several potential binding partners. However, the levels of expression were not identical; NRXN1 increased with age and NRXN2 levels were consistently higher than for NRXN3. Immunohistochemistry for each NRXN also revealed different expression patterns at this stage of development. NRXN1 and NRXN3 immunoreactivity was generally strongest in the cortical plate and increased in the ventricular zone with age, but was weak in the synaptogenic presubplate (pSP) and marginal zone. On the other hand, NRXN2 colocalized with synaptophysin in neurites of the pSP, but especially with GAP43 and CASK in growing axons of the intermediate zone. Alternative splicing modifies the role of NRXNs and we found evidence by RNAseq for exon skipping at splice site 4 and concomitant expression of KHDBRS proteins which control this splicing. NRXN2 may play a part in early cortical synaptogenesis, but NRXNs could have diverse roles in development including axon guidance, and intercellular communication between proliferating cells and/or migrating neurons.
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Affiliation(s)
- Lauren F Harkin
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
- Present address: School of Healthcare Science, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | - Susan J Lindsay
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
- Present address: Wellcome Trust, Sanger Institute, Cambridge, CB10 1SA, UK
| | - Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Alexandra Ferrara
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Emily A Gullon
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Owen G James
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
- Present address: MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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25
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Alzu'bi A, Lindsay S, Kerwin J, Looi SJ, Khalil F, Clowry GJ. Distinct cortical and sub-cortical neurogenic domains for GABAergic interneuron precursor transcription factors NKX2.1, OLIG2 and COUP-TFII in early fetal human telencephalon. Brain Struct Funct 2016; 222:2309-2328. [PMID: 27905023 PMCID: PMC5504260 DOI: 10.1007/s00429-016-1343-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 11/18/2016] [Indexed: 01/03/2023]
Abstract
The extent of similarities and differences between cortical GABAergic interneuron generation in rodent and primate telencephalon remains contentious. We examined expression of three interneuron precursor transcription factors, alongside other markers, using immunohistochemistry on 8–12 post-conceptional weeks (PCW) human telencephalon sections. NKX2.1, OLIG2, and COUP-TFII expression occupied distinct (although overlapping) neurogenic domains which extended into the cortex and revealed three CGE compartments: lateral, medial, and ventral. NKX2.1 expression was very largely confined to the MGE, medial CGE, and ventral septum confirming that, at this developmental stage, interneuron generation from NKX2.1+ precursors closely resembles the process observed in rodents. OLIG2 immunoreactivity was observed in GABAergic cells of the proliferative zones of the MGE and septum, but not necessarily co-expressed with NKX2.1, and OLIG2 expression was also extensively seen in the LGE, CGE, and cortex. At 8 PCW, OLIG2+ cells were only present in the medial and anterior cortical wall suggesting a migratory pathway for interneuron precursors via the septum into the medial cortex. By 12 PCW, OLIG2+ cells were present throughout the cortex and many were actively dividing but without co-expressing cortical progenitor markers. Dividing COUP-TFII+ progenitor cells were localized to ventral CGE as previously described but were also numerous in adjacent ventral cortex; in both the cases, COUP-TFII was co-expressed with PAX6 in proliferative zones and TBR1 or calretinin in post-mitotic cortical neurons. Thus COUP-TFII+ progenitors gave rise to pyramidal cells, but also interneurons which not only migrated posteriorly into the cortex from ventral CGE but also anteriorly via the LGE.
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Affiliation(s)
- Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, NE1 3BZ, UK.
| | - Janet Kerwin
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, NE1 3BZ, UK
| | - Shi Jie Looi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, NE1 3BZ, UK
| | - Fareha Khalil
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.,Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne, NE1 3BZ, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
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26
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Sohal HS, Clowry GJ, Jackson A, O’Neill A, Baker SN. Mechanical Flexibility Reduces the Foreign Body Response to Long-Term Implanted Microelectrodes in Rabbit Cortex. PLoS One 2016; 11:e0165606. [PMID: 27788240 PMCID: PMC5082854 DOI: 10.1371/journal.pone.0165606] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/15/2016] [Indexed: 02/04/2023] Open
Abstract
Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive microelectrodes. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We compared the glial response over a 26-96 week period following implantation in the rabbit cortex of microwires and a novel flexible electrode. Horizontal sections were used to obtain a depth profile of the radial distribution of microglia, astrocytes and neurofilament. We found that the flexible electrode was associated with decreased gliosis compared to the microwires over these long indwelling periods. This was in part due to a decrease in overall microgliosis and enhanced neuronal density around the flexible probe, especially at longer periods of implantation.
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Affiliation(s)
- Harbaljit S. Sohal
- Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhassett, NY, 11030, United States of America
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Gavin J. Clowry
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Andrew Jackson
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Anthony O’Neill
- School of Electrical and Electronic Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom
| | - Stuart N. Baker
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
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27
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Lindsay SJ, Xu Y, Lisgo SN, Harkin LF, Copp AJ, Gerrelli D, Clowry GJ, Talbot A, Keogh MJ, Coxhead J, Santibanez-Koref M, Chinnery PF. HDBR Expression: A Unique Resource for Global and Individual Gene Expression Studies during Early Human Brain Development. Front Neuroanat 2016; 10:86. [PMID: 27833533 PMCID: PMC5080337 DOI: 10.3389/fnana.2016.00086] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/12/2016] [Indexed: 12/21/2022] Open
Affiliation(s)
- Susan J Lindsay
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Steven N Lisgo
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Lauren F Harkin
- Institute of Genetic Medicine, Newcastle UniversityNewcastle upon Tyne, UK; Institute of Neuroscience, Newcastle UniversityNewcastle upon Tyne, UK
| | - Andrew J Copp
- Institute of Child Health, University College London London, UK
| | - Dianne Gerrelli
- Institute of Child Health, University College London London, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University Newcastle upon Tyne, UK
| | - Aysha Talbot
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Michael J Keogh
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
| | - Jonathan Coxhead
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
| | | | - Patrick F Chinnery
- Institute of Genetic Medicine, Newcastle University Newcastle upon Tyne, UK
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28
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Harkin LF, Gerrelli D, Gold Diaz DC, Santos C, Alzu'bi A, Austin CA, Clowry GJ. Distinct expression patterns for type II topoisomerases IIA and IIB in the early foetal human telencephalon. J Anat 2015; 228:452-63. [PMID: 26612825 PMCID: PMC4832326 DOI: 10.1111/joa.12416] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2015] [Indexed: 01/16/2023] Open
Abstract
TOP2A and TOP2B are type II topoisomerase enzymes that have important but distinct roles in DNA replication and RNA transcription. Recently, TOP2B has been implicated in the transcription of long genes in particular that play crucial roles in neural development and are susceptible to mutations contributing to neurodevelopmental conditions such as autism and schizophrenia. This study maps their expression in the early foetal human telencephalon between 9 and 12 post‐conceptional weeks. TOP2A immunoreactivity was restricted to cell nuclei of the proliferative layers of the cortex and ganglionic eminences (GE), including the ventricular zone and subventricular zone (SVZ) closely matching expression of the proliferation marker KI67. Comparison with sections immunolabelled for NKX2.1, a medial GE (MGE) marker, and PAX6, a cortical progenitor cell and lateral GE (LGE) marker, revealed that TOP2A‐expressing cells were more abundant in MGE than the LGE. In the cortex, TOP2B is expressed in cell nuclei in both proliferative (SVZ) and post‐mitotic compartments (intermediate zone and cortical plate) as revealed by comparison with immunostaining for PAX6 and the post‐mitotic neuron marker TBR1. However, co‐expression with KI67 was rare. In the GE, TOP2B was also expressed by proliferative and post‐mitotic compartments. In situ hybridisation studies confirmed these patterns of expression, except that TOP2A mRNA is restricted to cells in the G2/M phase of division. Thus, during early development, TOP2A is likely to have a role in cell proliferation, whereas TOP2B is expressed in post‐mitotic cells and may be important in controlling expression of long genes even at this early stage.
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Affiliation(s)
- Lauren F Harkin
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | | | | | - Chloe Santos
- HDBR Resource, UCL Institute of Child Health, London, UK
| | - Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Caroline A Austin
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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29
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Abstract
GABAergic interneurons are crucial to controlling the excitability and responsiveness of cortical circuitry. Their developmental origin may differ between rodents and human. We have demonstrated the expression of 12 GABAergic interneuron-associated genes in samples from human neocortex by quantitative rtPCR from 8 to 12 postconceptional weeks (PCW) and shown a significant anterior to posterior expression gradient, confirmed by in situ hybridization or immunohistochemistry for GAD1 and 2, DLX1, 2, and 5, ASCL1, OLIG2, and CALB2. Following cortical plate (CP) formation from 8 to 9 PCW, a proportion of cells were strongly stained for all these markers in the CP and presubplate. ASCL1 and DLX2 maintained high expression in the proliferative zones and showed extensive immunofluorescent double-labeling with the cell division marker Ki-67. CALB2-positive cells increased steadily in the SVZ/VZ from 10 PCW but were not double-labeled with Ki-67. Expression of GABAergic genes was generally higher in the dorsal pallium than in the ganglionic eminences, with lower expression in the intervening ventral pallium. It is widely accepted that the cortical proliferative zones may generate CALB2-positive interneurons from mid-gestation; we now show that the anterior neocortical proliferative layers especially may be a rich source of interneurons in the early neocortex.
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Affiliation(s)
- Nahidh Al-Jaberi
- Institute of Neuroscience Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Subrot Sarma
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Nadhim Bayatti
- Institute of Neuroscience Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK Current address: Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
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30
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Clowry GJ. An enhanced role and expanded developmental origins for gamma-aminobutyric acidergic interneurons in the human cerebral cortex. J Anat 2014; 227:384-93. [PMID: 24839870 DOI: 10.1111/joa.12198] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2014] [Indexed: 12/16/2022] Open
Abstract
Human beings have considerably expanded cognitive abilities compared with all other species and they also have a relatively larger cerebral cortex compared with their body size. But is a bigger brain the only reason for higher cognition or have other features evolved in parallel? Humans have more and different types of GABAergic interneurons, found in different places, than our model species. Studies are beginning to show differences in function. Is this expanded repertoire of functional types matched by an evolution of their developmental origins? Recent studies support the idea that generation of interneurons in the ventral telencephalon may be more complicated in primates, which have evolved a large and complex outer subventricular zone in the ganglionic eminences. In addition, proportionally more interneurons appear to be produced in the caudal ganglionic eminence, the majority of which populate the superficial layers of the cortex. Whether or not the cortical proliferative zones are a source of interneurogenesis, and to what extent and of what significance, is a contentious issue. As there is growing evidence that conditions such as autism, schizophrenia and congenital epilepsy may have developmental origins in the failure of interneuron production and migration, it is important we understand fully the similarities and differences between human development and our animal models.
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Affiliation(s)
- Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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31
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Sohal HS, Jackson A, Jackson R, Clowry GJ, Vassilevski K, O'Neill A, Baker SN. The sinusoidal probe: a new approach to improve electrode longevity. Front Neuroeng 2014; 7:10. [PMID: 24808859 PMCID: PMC4010751 DOI: 10.3389/fneng.2014.00010] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 04/07/2014] [Indexed: 11/13/2022]
Abstract
Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive brain-machine interfaces. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We have designed a sinusoidal probe in order to reduce movement of the recording tip relative to the surrounding neural tissue. The probe was microfabricated from flexible materials and incorporated a sinusoidal shaft to minimize tethering forces and a 3D spheroid tip to anchor the recording site within the brain. Compared to standard microwire electrodes, the signal-to-noise ratio and local field potential power of sinusoidal probe recordings from rabbits was more stable across recording periods up to 678 days. Histological quantification of microglia and astrocytes showed reduced neuronal tissue damage especially for the tip region between 6 and 24 months post-implantation. We suggest that the micromotion-reducing measures incorporated into our design, at least partially, decreased the magnitude of gliosis, resulting in enhanced longevity of recording.
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Affiliation(s)
- Harbaljit S Sohal
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK ; School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Andrew Jackson
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK
| | - Richard Jackson
- School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Gavin J Clowry
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK
| | - Konstantin Vassilevski
- School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Anthony O'Neill
- School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Stuart N Baker
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK
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Simon A, Traub RD, Vladimirov N, Jenkins A, Nicholson C, Whittaker RG, Schofield I, Clowry GJ, Cunningham MO, Whittington MA. Gap junction networks can generate both ripple-like and fast ripple-like oscillations. Eur J Neurosci 2013; 39:46-60. [PMID: 24118191 DOI: 10.1111/ejn.12386] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 09/03/2013] [Accepted: 09/10/2013] [Indexed: 11/30/2022]
Abstract
Fast ripples (FRs) are network oscillations, defined variously as having frequencies of > 150 to > 250 Hz, with a controversial mechanism. FRs appear to indicate a propensity of cortical tissue to originate seizures. Here, we demonstrate field oscillations, at up to 400 Hz, in spontaneously epileptic human cortical tissue in vitro, and present a network model that could explain FRs themselves, and their relation to 'ordinary' (slower) ripples. We performed network simulations with model pyramidal neurons, having axons electrically coupled. Ripples (< 250 Hz) were favored when conduction of action potentials, axon to axon, was reliable. Whereas ripple population activity was periodic, firing of individual axons varied in relative phase. A switch from ripples to FRs took place when an ectopic spike occurred in a cell coupled to another cell, itself multiply coupled to others. Propagation could then start in one direction only, a condition suitable for re-entry. The resulting oscillations were > 250 Hz, were sustained or interrupted, and had little jitter in the firing of individual axons. The form of model FR was similar to spontaneously occurring FRs in excised human epileptic tissue. In vitro, FRs were suppressed by a gap junction blocker. Our data suggest that a given network can produce ripples, FRs, or both, via gap junctions, and that FRs are favored by clusters of axonal gap junctions. If axonal gap junctions indeed occur in epileptic tissue, and are mediated by connexin 26 (recently shown to mediate coupling between immature neocortical pyramidal cells), then this prediction is testable.
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Affiliation(s)
- Anna Simon
- Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
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Ehrmann I, Dalgliesh C, Liu Y, Danilenko M, Crosier M, Overman L, Arthur HM, Lindsay S, Clowry GJ, Venables JP, Fort P, Elliott DJ. The tissue-specific RNA binding protein T-STAR controls regional splicing patterns of neurexin pre-mRNAs in the brain. PLoS Genet 2013; 9:e1003474. [PMID: 23637638 PMCID: PMC3636136 DOI: 10.1371/journal.pgen.1003474] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 03/07/2013] [Indexed: 11/18/2022] Open
Abstract
The RNA binding protein T-STAR was created following a gene triplication 520-610 million years ago, which also produced its two parologs Sam68 and SLM-1. Here we have created a T-STAR null mouse to identify the endogenous functions of this RNA binding protein. Mice null for T-STAR developed normally and were fertile, surprisingly, given the high expression of T-STAR in the testis and the brain, and the known infertility and pleiotropic defects of Sam68 null mice. Using a transcriptome-wide search for splicing targets in the adult brain, we identified T-STAR protein as a potent splicing repressor of the alternatively spliced segment 4 (AS4) exons from each of the Neurexin1-3 genes, and exon 23 of the Stxbp5l gene. T-STAR protein was most highly concentrated in forebrain-derived structures like the hippocampus, which also showed maximal Neurexin1-3 AS4 splicing repression. In the absence of endogenous T-STAR protein, Nrxn1-3 AS4 splicing repression dramatically decreased, despite physiological co-expression of Sam68. In transfected cells Neurexin3 AS4 alternative splicing was regulated by either T-STAR or Sam68 proteins. In contrast, Neurexin2 AS4 splicing was only regulated by T-STAR, through a UWAA-rich response element immediately downstream of the regulated exon conserved since the radiation of bony vertebrates. The AS4 exons in the Nrxn1 and Nrxn3 genes were also associated with distinct patterns of conserved UWAA repeats. Consistent with an ancient mechanism of splicing control, human T-STAR protein was able to repress splicing inclusion of the zebrafish Nrxn3 AS4 exon. Although Neurexin1-3 and Stxbp5l encode critical synaptic proteins, T-STAR null mice had no detectable spatial memory deficits, despite an almost complete absence of AS4 splicing repression in the hippocampus. Our work identifies T-STAR as an ancient and potent tissue-specific splicing regulator that uses a concentration-dependent mechanism to co-ordinately regulate regional splicing patterns of the Neurexin1-3 AS4 exons in the mouse brain.
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Affiliation(s)
- Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yilei Liu
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Marina Danilenko
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Moira Crosier
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lynn Overman
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Helen M. Arthur
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gavin J. Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Julian P. Venables
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Philippe Fort
- Universités Montpellier 2 et 1, UMR 5237, Centre de Recherche de Biochimie Macromoléculaire, CNRS, Montpellier, France
| | - David J. Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
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Ip BK, Bayatti N, Howard NJ, Lindsay S, Clowry GJ. The corticofugal neuron-associated genes ROBO1, SRGAP1, and CTIP2 exhibit an anterior to posterior gradient of expression in early fetal human neocortex development. Cereb Cortex 2011; 21:1395-407. [PMID: 21060114 PMCID: PMC3097990 DOI: 10.1093/cercor/bhq219] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Developing neocortical progenitors express transcription factors in gradients that induce programs of region-specific gene expression. Our previous work identified anteriorly upregulated expression gradients of a number of corticofugal neuron-associated gene probe sets along the anterior-posterior axis of the human neocortex (8-12 postconceptional weeks [PCW]). Here, we demonstrate by real-time polymerase chain reaction, in situ hybridization and immunohistochemistry that 3 such genes, ROBO1, SRGAP1, and CTIP2 are highly expressed anteriorly between 8-12 PCW, in comparison with other genes (FEZF2, SOX5) expressed by Layer V, VI, and subplate neurons. All 3 were prominently expressed by early postmitotic neurons in the subventricular zone, intermediate zone, and cortical plate (CP) from 8 to 10 PCW. Between 12 and 15 PCW expression patterns for ER81 and SATB2 (Layer V), TBR1 (Layer V/VI) and NURR1 (Layer VI) revealed Layer V forming. By 15 PCW, ROBO1 and SRGAP1 expression was confined to Layer V, whereas CTIP2 was expressed throughout the CP anteriorly. We observed ROBO1 and SRGAP1 immunoreactivity in medullary corticospinal axons from 11 PCW onward. Thus, we propose that the coexpression of these 3 markers in the anterior neocortex may mark the early location of the human motor cortex, including its corticospinal projection neurons, allowing further study of their early differentiation.
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Affiliation(s)
- Bui Kar Ip
- Institute of Human Genetics and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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Ip BK, Wappler I, Peters H, Lindsay S, Clowry GJ, Bayatti N. Investigating gradients of gene expression involved in early human cortical development. J Anat 2010; 217:300-11. [PMID: 20579172 PMCID: PMC2992409 DOI: 10.1111/j.1469-7580.2010.01259.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2010] [Indexed: 11/30/2022] Open
Abstract
The division of the neocortex into functional areas (the cortical map) differs little between individuals, although brain lesions in development can lead to substantial re-organization of regional identity. We are studying how the cortical map is established in the human brain as a first step towards understanding this plasticity. Previous work on rodent development has identified certain transcription factors (e.g. Pax6, Emx2) expressed in gradients across the neocortex that appear to control regional expression of cell adhesion molecules and organization of area-specific thalamocortical afferent projections. Although mechanisms may be shared, the human neocortex is composed of different and more complex local area identities. Using Affymetrix gene chips of human foetal brain tissue from 8 to 12.5 post-conceptional weeks [PCW, equivalent to Carnegie stage (CS) 23, to Foetal stage (F) 4], human material obtained from the MRC-Wellcome Trust Human Developmental Biology Resource (http://www.hdbr.org), we have identified a number of genes that exhibit gradients along the anterior-posterior axis of the neocortex. Gene probe sets that were found to be upregulated posteriorally compared to anteriorally, included EMX2, COUPTFI and FGF receptor 3, and those upregulated anteriorally included cell adhesion molecules such as cadherins and protocadherins, as well as potential motor cortex markers and frontal markers (e.g. CNTNAP2, PCDH17, ROBO1, and CTIP2). Confirmation of graded expression for a subset of these genes was carried out using real-time PCR. Furthermore, we have established a dissociation cell culture model utilizing tissue dissected from anteriorally or posteriorally derived developing human neocortex that exhibits similar gradients of expression of these genes for at least 72 h in culture.
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Affiliation(s)
- Bui K Ip
- Institute of Human Genetics, Newcastle UniversityNewcastle upon Tyne, UK
- Institute of Neuroscience, Newcastle UniversityNewcastle upon Tyne, UK
| | - Ilka Wappler
- Institute of Human Genetics, Newcastle UniversityNewcastle upon Tyne, UK
| | - Heiko Peters
- Institute of Human Genetics, Newcastle UniversityNewcastle upon Tyne, UK
| | - Susan Lindsay
- Institute of Human Genetics, Newcastle UniversityNewcastle upon Tyne, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle UniversityNewcastle upon Tyne, UK
| | - Nadhim Bayatti
- Institute of Human Genetics, Newcastle UniversityNewcastle upon Tyne, UK
- Institute of Neuroscience, Newcastle UniversityNewcastle upon Tyne, UK
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Wang WZ, Hoerder-Suabedissen A, Oeschger FM, Bayatti N, Ip BK, Lindsay S, Supramaniam V, Srinivasan L, Rutherford M, Møllgård K, Clowry GJ, Molnár Z. Subplate in the developing cortex of mouse and human. J Anat 2010; 217:368-80. [PMID: 20727056 PMCID: PMC2992414 DOI: 10.1111/j.1469-7580.2010.01274.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2010] [Indexed: 01/04/2023] Open
Abstract
The subplate is a largely transient zone containing precocious neurons involved in several key steps of cortical development. The majority of subplate neurons form a compact layer in mouse, but are dispersed throughout a much larger zone in the human. In rodent, subplate neurons are among the earliest born neocortical cells, whereas in primate, neurons are added to the subplate throughout cortical neurogenesis. Magnetic resonance imaging and histochemical studies show that the human subplate grows in size until the end of the second trimester. Previous microarray experiments in mice have shown several genes that are specifically expressed in the subplate layer of the rodent dorsal cortex. Here we examined the human subplate for some of these markers. In the human dorsal cortex, connective tissue growth factor-positive neurons can be seen in the ventricular zone at 15-22 postconceptional weeks (PCW) (most at 17 PCW) and are present in the subplate at 22 PCW. The nuclear receptor-related 1 protein is mostly expressed in the subplate in the dorsal cortex, but also in lower layer 6 in the lateral and perirhinal cortex, and can be detected from 12 PCW. Our results suggest that connective tissue growth factor- and nuclear receptor-related 1-positive cells are two distinct cell populations of the human subplate. Furthermore, our microarray analysis in rodent suggested that subplate neurons produce plasma proteins. Here we demonstrate that the human subplate also expresses α2zinc-binding globulin and Alpha-2-Heremans-Schmid glycoprotein/human fetuin. In addition, the established subplate neuron marker neuropeptide Y is expressed superficially, whereas potassium/chloride co-transporter (KCC2)-positive neurons are localized in the deep subplate at 16 PCW. These observations imply that the human subplate shares gene expression patterns with rodent, but is more compartmentalized into superficial and deep sublayers. This increased complexity of the human subplate may contribute to differential vulnerability in response to hypoxia/ischaemia across the depth of the cortex. Combining knowledge of cell-type specific subplate gene expression with modern imaging methods will enable a better understanding of neuropathologies involving the subplate.
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Affiliation(s)
- Wei Zhi Wang
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| | | | | | - Nadhim Bayatti
- Institute of Human Genetics and Institute of Neuroscience, Newcastle UniversityNewcastle, UK
| | - Bui Kar Ip
- Institute of Human Genetics and Institute of Neuroscience, Newcastle UniversityNewcastle, UK
| | - Susan Lindsay
- Institute of Human Genetics and Institute of Neuroscience, Newcastle UniversityNewcastle, UK
| | - Veena Supramaniam
- Perinatal Imaging, MRC Clinical Sciences Centre, Hammersmith HospitalLondon, UK
| | - Latha Srinivasan
- Perinatal Imaging, MRC Clinical Sciences Centre, Hammersmith HospitalLondon, UK
| | - Mary Rutherford
- Perinatal Imaging, MRC Clinical Sciences Centre, Hammersmith HospitalLondon, UK
| | - Kjeld Møllgård
- Institut for Cellular and Molecular Medicine, Panum Institute, University of CopenhagenBlegdamsvej Copenhagen N, Denmark
| | - Gavin J Clowry
- Institute of Human Genetics and Institute of Neuroscience, Newcastle UniversityNewcastle, UK
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
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Chen A, Siow B, Blamire AM, Lako M, Clowry GJ. Transplantation of magnetically labeled mesenchymal stem cells in a model of perinatal brain injury. Stem Cell Res 2010; 5:255-66. [PMID: 20875955 DOI: 10.1016/j.scr.2010.08.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 08/20/2010] [Accepted: 08/20/2010] [Indexed: 11/24/2022] Open
Abstract
Periventricular white matter injury (PVWMI) in preterm infants is a leading cause of cerebral palsy. Mesenchymal stem cell (MSC) transplantation in experimental models of adult demyelinating conditions is reported to reduce neurological deficits so we investigated their potential for treating developmental PVWMI. Neonatal rat MSCs, when cultured and labeled in vitro with fluorescent, micrometer-sized paramagnetic iron oxide particles (MPIO), retained their differentiation potential. Rats received bilateral intracerebral injections of ibotenic acid at postnatal day 5 causing PVWMI-like lesions with localized hypomyelination and sensorimotor deficits. MPIO-labeled MSCs were transplanted near the lesion in the right hemisphere 1 day postlesioning. Animals receiving cell transplants showed significantly increased antimyelin immunoreactivity in the corpus callosum, and improved reaching and retrieval skills, compared to animals receiving conditioned medium only. In separate experiments, in vivo MRI demonstrated that MPIO-labeled cells migrated away from the injection site toward lesioned areas in both hemispheres, confirmed by microscopy postmortem, but double-labeling studies found little evidence of differentiation into neural phenotypes. MSC transplantation led to significantly more forebrain cell proliferation, assayed by bromodeoxyuridine incorporation, than in controls. MSC transplants may have been neuroprotective and indirectly contributed to brain repair.
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Affiliation(s)
- Aiqing Chen
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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38
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Basu AP, Graziadio S, Smith M, Clowry GJ, Cioni G, Eyre JA. Response to Dr Papathanasiou. Ann Neurol 2010. [DOI: 10.1002/ana.22038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Basu A, Graziadio S, Smith M, Clowry GJ, Cioni G, Eyre JA. Developmental plasticity connects visual cortex to motoneurons after stroke. Ann Neurol 2010; 67:132-6. [PMID: 20186850 DOI: 10.1002/ana.21827] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We report motor cortical function in the left occipital cortex of a subject who suffered a left middle cerebral artery stroke early in development. Transcranial magnetic stimulation of the left occipital cortex evoked contraction of right hand muscles. Electroencephalogram recorded over the left occipital cortex showed: 1) coherence with electromyogram from a right hand muscle; 2) a typical sensorimotor Mu rhythm at rest that was suppressed during contraction of right hand muscles. This is the first evidence that cortical plasticity extends beyond reshaping of primary sensory cortical fields to respecification of the cortical origin of subcortically projecting pathways.
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Affiliation(s)
- Anna Basu
- Developmental Neuroscience, Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK
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40
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Fisher T, Clowry GJ. Elimination of muscle afferent boutons from the cuneate nucleus of the rat medulla during development. Neuroscience 2009; 161:787-93. [PMID: 19362134 DOI: 10.1016/j.neuroscience.2009.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 03/19/2009] [Accepted: 04/04/2009] [Indexed: 11/19/2022]
Abstract
There is developmental refinement of the proprioreceptive muscle afferent input to the rat ventral horn. This study explored the extent to which this occurs in the medulla. Muscle afferents were transganglionically labeled from the extensor digitorum communis forelimb muscle with cholera toxin B subunit. Tracer amounts and transport times were adjusted for animal size. Immunohistochemistry revealed tracer localization in the medulla and dorsal root ganglia. Labeled muscle afferent boutons were counted in the cuneate nucleus between postnatal days 7 and 42, during which time a large decrease in the density of labeled boutons was observed qualitatively. Localization of input to dorsolateral parts of the nucleus remained broadly the same at different ages, although disappearance of a marked innervation of ventromedial regions in more caudal sections was observed. Bouton counts were corrected for growth of the medulla with age, and any spread of tracer to adjacent muscles indicated by counts of labeled dorsal root ganglion neurons. There was a statistically significant, approximately 40% reduction in the number of muscle afferent boutons in the cuneate nucleus during this developmental period. Previous studies suggest that perturbations to the corticospinal input during a developmental critical period influence the eventual size of the muscle afferent input to the ventral horn. Corticocuneate fibers invade the nucleus during the same period and may influence reorganization of its muscle afferent input, making it another potential site for aberrant reflex development in cerebral palsy.
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Affiliation(s)
- T Fisher
- Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne, UK
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Bayatti N, Sarma S, Shaw C, Eyre JA, Vouyiouklis DA, Lindsay S, Clowry GJ. Progressive loss of PAX6, TBR2, NEUROD and TBR1 mRNA gradients correlates with translocation of EMX2 to the cortical plate during human cortical development. Eur J Neurosci 2009; 28:1449-56. [PMID: 18973570 PMCID: PMC2675014 DOI: 10.1111/j.1460-9568.2008.06475.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The transcription factors Emx2 and Pax6 are expressed in the proliferating zones of the developing rodent neocortex, and gradients of expression interact in specifying caudal and rostral identities. Pax6 is also involved in corticoneurogenesis, being expressed by radial glial progenitors that give rise to cells that also sequentially express Tbr2, NeuroD and Tbr1, genes temporally downstream of Pax6. In this study, using in situ hybridization, we analysed the expression of EMX2, PAX6, TBR2, NEUROD and TBR1 mRNA in the developing human cortex between 8 and 12 postconceptional weeks (PCW). EMX2 mRNA was expressed in the ventricular (VZ) and subventricular zones (SVZ), but also in the cortical plate, unlike in the rodent. However, gradients of expression were similar to that of the rodent at all ages studied. PAX6 mRNA expression was limited to the VZ and SVZ. At 8 PCW, PAX6 was highly expressed rostrally but less so caudally, as has been seen in the rodent, however this gradient disappeared early in corticogenesis, by 9 PCW. There was less restricted compartment-specific expression of TBR2, NEUROD and TBR1 mRNA than in the rodent, where the gradients of expression were similar to that of PAX6 prior to 9 PCW. The gradient disappeared for TBR2 by 10 PCW, and for NEUROD and TBR1 by 12 PCW. These data support recent reports that EMX2 but not PAX6 is more directly involved in arealization, highlighting that analysis of human development allows better spatio-temporal resolution than studies in rodents.
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Affiliation(s)
- Nadhim Bayatti
- Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, UK
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Eyre JA, Smith M, Dabydeen L, Clowry GJ, Petacchi E, Battini R, Guzzetta A, Cioni G. Is hemiplegic cerebral palsy equivalent to amblyopia of the corticospinal system? Ann Neurol 2007; 62:493-503. [PMID: 17444535 DOI: 10.1002/ana.21108] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Subjects with severe hemiplegic cerebral palsy have increased ipsilateral corticospinal projections from their noninfarcted cortex. We investigated whether their severe impairment might, in part, be caused by activity-dependent, competitive displacement of surviving contralateral corticospinal projections from the affected cortex by more active ipsilateral corticospinal projections from the nonaffected cortex, thereby compounding the impairment. METHODS Transcranial magnetic stimulation (TMS) characterized corticospinal tract development from each hemisphere over the first 2 years in 32 healthy children, 14 children with unilateral stroke, and 25 with bilateral lesions. Magnetic resonance imaging and anatomic studies compared corticospinal tract growth in 13 patients with perinatal stroke with 46 healthy subjects. RESULTS Infants with unilateral lesions initially had responses after TMS of the affected cortex, which became progressively more abnormal, and seven were eventually lost. There was associated hypertrophy of the ipsilateral corticospinal axons projecting from the noninfarcted cortex. Magnetic resonance imaging and anatomic studies demonstrated hypertrophy of the corticospinal tract from the noninfarcted hemisphere. TMS findings soon after the stroke did not predict impairment; subsequent loss of responses and hypertrophy of ipsilateral corticospinal axons from the noninfarcted cortex predicted severe impairment at 2 years. Infants with bilateral lesions maintained responses to TMS from both hemispheres with a normal pattern of development. INTERPRETATION Rather than representing "reparative plasticity," increased ipsilateral projections from the noninfarcted cortex compound disability by competitively displacing surviving contralateral corticospinal projections from the infarcted cortex. This may provide a pathophysiological explanation for why signs of hemiplegic cerebral palsy appear late and progress over the first 2 years of life.
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Affiliation(s)
- Janet A Eyre
- Department of Developmental Neuroscience, School of Clinical Medical Sciences, University of Newcastle, Newcastle upon Tyne, United Kingdom.
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Bayatti N, Moss JA, Sun L, Ambrose P, Ward JFH, Lindsay S, Clowry GJ. A molecular neuroanatomical study of the developing human neocortex from 8 to 17 postconceptional weeks revealing the early differentiation of the subplate and subventricular zone. Cereb Cortex 2007; 18:1536-48. [PMID: 17965125 PMCID: PMC2430151 DOI: 10.1093/cercor/bhm184] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have employed immunohistochemistry for multiple markers to investigate the structure and possible function of the different compartments of human cerebral wall from the formation of cortical plate at 8 postconceptional weeks (PCW) to the arrival of thalamocortical afferents at 17 PCW. New observations include the subplate emerging as a discrete differentiated layer by 10 PCW, characterized by synaptophysin and vesicular gamma-aminobutyric acid transporter expression also seen in the marginal zone, suggesting that these compartments may maintain a spontaneously active synaptic network even before the arrival of thalamocortical afferents. The subplate expanded from 13 to 17 PCW, becoming the largest compartment and differentiated further, with NPY neurons located in the outer subplate and KCC2 neurons in the inner subplate. Glutamate decarboxylase and calretinin-positive inhibitory neurons migrated tangentially and radially from 11.5 PCW, appearing in larger numbers toward the rostral pole. The proliferative zones, marked by Ki67 expression, developed a complicated structure by 12.5 PCW reflected in transcription factor expression patterns, including TBR2 confined to the inner subventricular and outer ventricular zones and TBR1 weakly expressed in the subventricular zone (SVZ). PAX6 was extensively expressed in the proliferative zones such that the human outer SVZ contained a large reservoir of PAX6-positive potential progenitor cells.
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Affiliation(s)
- Nadhim Bayatti
- School of Clinical Medical Sciences, Department of Child Health, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, UK
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Clowry GJ. The dependence of spinal cord development on corticospinal input and its significance in understanding and treating spastic cerebral palsy. Neurosci Biobehav Rev 2007; 31:1114-24. [PMID: 17544509 DOI: 10.1016/j.neubiorev.2007.04.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 04/24/2007] [Indexed: 11/18/2022]
Abstract
The final phase of spinal cord development follows the arrival of descending pathways which brings about a reorganisation that allows mature motor behaviours to emerge under the control of higher brain centres. Observations made during typical human development have shown that low threshold stretch reflexes, including excitatory reflexes between agonist and antagonist muscle pairs are a feature of the newborn. However, perinatal lesions of the corticospinal tract can lead to abnormal development of spinal reflexes that includes retention and reinforcement of developmental features that do not emerge in adult stroke victims, even though they also suffer from spasticity. This review describes investigations in animal models into how corticospinal input may drive segmental maturation. It compares their findings with observations made in humans and discusses how therapeutic interventions in cerebral palsy might aim to correct imbalances between descending and segmental inputs, bearing in mind that descending activity may play the crucial role in development.
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Affiliation(s)
- Gavin J Clowry
- Neural Development, Plasticity and Repair, School of Clinical Medical Sciences and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
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Clowry GJ, Walker L, Davies P. The effects of botulinum neurotoxin A induced muscle paresis during a critical period upon muscle and spinal cord development in the rat. Exp Neurol 2006; 202:456-69. [PMID: 16928374 DOI: 10.1016/j.expneurol.2006.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 07/11/2006] [Accepted: 07/12/2006] [Indexed: 11/29/2022]
Abstract
The second postnatal week is a critical period in rat motor development. The expansion of corticospinal innervation coincides with elimination of polyneuronal innervation of muscles, onset of quadrupedal locomotion and refinement of muscle afferent input to the ventral horn. Such developmental events are believed to be activity-dependent. In the present study, muscle afferent activity was temporarily reduced by injecting distal forelimb muscles with botulinum toxin A (BTX). Injections of toxin or saline were made unilaterally on postnatal day (P) 7 which in BTX-treated animals lead to a profound loss of movement in the affected limb over the next week before function returned. The neural tracer cholera toxin B (CTB) was injected into the extensor digitorum communis (EDC) at either P14 or P28. Allowing 3 days for tracer transport, the spinal cords were sectioned and immunostained for CTB and cJun. In separate experiments, behavioural testing of the forelimb was carried out between P35 and P49. Then, sections of EDC muscle were immunostained for slow myosin. An increased density of ventral horn muscle afferent boutons was observed at P17 in BTX-treated animals compared to controls, however, by P31, this difference was not significant. However, CTB labelling also revealed significantly increased motor axon terminals in the ventral Renshaw cell region in BTX-treated animals at P31, accompanied by raised expression of cJun in ipsilateral motoneurones. BTX-treated animals showed deficits in ladder walking, and their muscles contained a higher density and significantly more clustering of slow myosin expressing muscle fibres than controls. Temporary reduction in activity did not significantly alter muscle afferent development, but temporary blockade of neuromuscular junctions did affect both muscle and motor axon, in the longer term.
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Affiliation(s)
- Gavin J Clowry
- Neural Development, Plasticity and Repair, School of Clinical Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.
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Abstract
Sections from all spinal cord levels from 20 human fetuses, age range 7.5-17 gestational weeks (GW) were immunostained for non-phosphorylated neurofilaments (to reveal motoneurones, spinocerebellar neurones and other large neurones), the calcium-binding protein parvalbumin (large proprioreceptive afferents), growth-associated protein 43 kDa (growing axons), glial fibrillary acidic protein (radial glia), synaptophysin (synaptic terminals) the cell-cell recognition molecule ephrin A4 (EphA4) and the ETS transcription factor Er81 (subclasses of motoneurone and proprioreceptive neurone). Muscle afferents crossed the dorsal horn by 7.5 GW and innervated motoneurones by 9 GW. An alignment of glial fibres guided them from dorsal columns to ventral horn, at right angles to the radial glia. They continued to provide a dense innervation of motoneurone pools up to 17 GW. By 13 GW motoneurones were segregated into distinct columns, all of which expressed EphA4 although only certain lateral groups expressed Er81. However, Er81 expression was more widespread amongst dorsal root ganglion neurones. From 9 GW Clarke's column neurones were identified and by 14 GW were heavily innervated by parvalbumin-positive afferents whilst their efferent axons could be traced to the lateral funiculus. This investigation contributes towards a timetable for the functional development of human motor control and makes comparisons with well-studied rodent models.
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Affiliation(s)
- Gavin J Clowry
- Neural Development, Plasticity and Repair Group, School of Clinical Medical Sciences, University of Newcastle upon Tyne, UK.
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Clowry GJ, Davies BM, Upile NS, Gibson CL, Bradley PM. Spinal cord plasticity in response to unilateral inhibition of the rat motor cortex during development: changes to gene expression, muscle afferents and the ipsilateral corticospinal projection. Eur J Neurosci 2005; 20:2555-66. [PMID: 15548199 DOI: 10.1111/j.1460-9568.2004.03713.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In developing Wistar albino rats, ventral horn muscle afferent boutons are lost following corticospinal innervation. Motor cortex lesions rescue a proportion of these boutons and perturb activity dependent expression of cJun and parvalbumin (PV) in the spinal cord. Therefore, we tested whether activity-dependent competition between corticospinal and proprioreceptive afferents determines the balance of these inputs to motor output pathways by delivering the inhibitory GABA agonist muscimol unilaterally to the forelimb motor cortex using slow release polymer implants from postnatal day 7 (P7) coincident with corticospinal synaptogenesis. Controls received saline. Inhibition of immature cortical neurons by muscimol was confirmed with separate in vitro electrophysiological recordings. After P28, spinal cord sections were immunostained for PV, cJun and muscle afferents transganglionically labelled with cholera toxin-B (CTB). Unilateral inhibition reduced contralaterally the number of PV positive spinal cord neurons and muscle afferent boutons in the dorsolateral ventral horn, compared to controls, and significantly altered the distribution of motoneuronal cJun expression. Separately, descending tracts were retrogradely traced with CTB from the cervical hemicord contralateral to implants. Forelimb sensorimotor cortex sections were immunostained for either CTB or PV. In muscimol treated animals, significantly fewer neurons expressed PV in the inhibited hemicortex, but as many CTB labelled corticospinal neurons were present as in controls, along with an equally large corticospinal projection from contralateral to the implant, significantly greater than in controls. Unexpectedly, unilateral inhibition of the motor cortical input did not lead to an expanded muscle afferent input. Instead, this was reduced coincident with development of a bilateral corticospinal innervation.
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Affiliation(s)
- G J Clowry
- Neural Development, Plasticity and Repair Group, School of Clinical Medical Sciences, University of Newcastle, Newcastle upon Tyne, United Kingdom.
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Abstract
Degenerative motoneurone diseases, whether in humans, animals, or transgenic mouse models, do not affect all types of motoneurone to the same degree. Understanding the relative differences in vulnerability of certain motor pools may be the key to developing therapies. Expression of calbindin (CB) and parvalbumin (PV) immunoreactivity, which are potentially neuroprotective calcium-binding proteins, and NADPH-diaphorase (NADPH-d) histochemical reactivity, a marker for neurodegeneration, was studied in brainstem sections from mutant wobbler mice and their normal littermates during the motoneurone degeneration phase (3-8 weeks of age). The motor trigeminal and facial nuclei reacted in a manner previously observed in spinal somatic motoneurones in the wobbler. Many motoneurones expressed moderate NADPH-d reactivity, correlated with the appearance of vacuolated motoneurones in Nissl-stained sections. This was not observed in littermate controls. Motoneurone counts from Nissl-stained sections from 14-month-old wobblers and littermates revealed significantly fewer (approximately 27%) motoneurones in the trigeminal nucleus of wobblers. In contrast, the wobbler hypoglossal nucleus contained neither vacuolated nor NADPH-d reactive motoneurones. However, expression of CB immunoreactivity by the majority of wobbler hypoglossal motoneurones was observed but not in littermate controls or in any other motor nucleus. Counts in older animals showed a smaller but still significant difference in motoneurone number between wobblers and controls (approximately 9% reduction). Finally, the wobbler abducens nucleus displayed neither vacuolated neurones, nor NADPH-d reactivity nor CB immunoreactivity. Motor nuclei innervating extraocular muscles appear to be protected in many forms of motoneurone disease in man and other species. However, there were still markedly fewer abducens motoneurones in the old wobblers compared to controls (approximately 29% reduction). Sparing of oculomotor neurones in other diseases has been attributed to their relatively high PV expression, which we also observed in the abducens nucleus of both wobblers and littermates, and to a lesser extent in the other motor nuclei too. In conclusion, our results suggest that, in the wobbler mouse, motoneurone degeneration may occur without overt signs such as cell body vacuolation and NADPH-d expression. Induced CB expression may be neuroprotective but that constitutive expression of PV may not.
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Affiliation(s)
- G J Clowry
- Neural Development, Plasticity and Repair Group, School of Clinical Medical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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Gibson CL, Clowry GJ. The effect on motor cortical neuronal development of focal lesions to the sub-cortical white matter in the neonatal rat: a model for periventricular leukomalacia. Int J Dev Neurosci 2003; 21:171-82. [PMID: 12781784 DOI: 10.1016/s0736-5748(03)00041-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Periventricular leukomalacia (PVL) is either a diffuse or cystic lesion of the periventricular white matter that leaves the overlying cortical grey matter largely intact. It is believed to result from hypoxia occurring pre- or perinatally and is a major cause of cerebral palsy. We have modelled PVL in rats comparing the effects of discrete injections of 3-nitropropionic acid (3-NP), a mitochondrial toxin, ibotenic acid (IBA), a glutamate analogue, or saline into the sub-cortical white matter on postnatal day 7 (P7). Following recovery times ranging from 3 days to 4 weeks, forebrain sections were Nissl stained or immunostained for Bax, cJun, calbindin (CB), parvalbumin (PV) or non-phosphorylated neurofilaments (NPNF). Compared to saline injections, ibotenic acid caused large lesions of both grey and white matter not characteristic of periventricular leukomalacia. 3-Nitropropionic acid injections caused small focal lesions restricted to the sub-cortical white matter. 3-Nitropropionic acid treatment initially increased expression of the apoptosis promoting proteins Bax and cJun, as well as non-phosphorylated neurofilaments in cortical layer V overlying the injection site. Non-phosphorylated neurofilament expression distal to the lesion was decreased representing a loss of cortical axons, but persisted and even increased with time within the cortex, demonstrating persistence of the parent cell bodies and local sprouting of neurites. There were significantly fewer calbindin and parvalbumin positive neurones in the motor cortex (MC) side ipsilateral to the 3-nitropropionic acid injection compared to the contralateral side. These persistent differences in expression of activity sensitive calcium binding proteins suggest alterations in local cortical circuitry without substantial loss of grey matter as is characteristic of periventricular leukomalacia. Changes in expression of Bax, cJun and non-phosphorylated neurofilaments during normal development are also described.
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Affiliation(s)
- Claire L Gibson
- Brain Development, Plasticity and Repair Group, School of Clinical Medical Sciences (Child Health), University of Newcastle upon Tyne, UK
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Dobson CB, Villagra F, Clowry GJ, Smith M, Kenwrick S, Donnai D, Miller S, Eyre JA. Abnormal corticospinal function but normal axonal guidance in human L1CAM mutations. Brain 2001; 124:2393-406. [PMID: 11701594 DOI: 10.1093/brain/124.12.2393] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
L1 cell adhesion molecule (L1CAM) gene mutations are associated with X-linked 'recessive' neurological syndromes characterized by spasticity of the legs. L1CAM knock-out mice show hypoplasia of the corticospinal tract and failure of corticospinal axonal decussation and projection beyond the cervical spinal cord. The aim of this study was to determine if similar neuropathology underlies the spastic diplegia of males hemizygous for L1CAM mutations. Studies were performed on eight carrier females and 10 hemizygous males. Transcranial magnetic stimulation excited the corticospinal tract and responses were recorded in biceps brachii and quadriceps femoris. In contralateral biceps and quadriceps the responses had high thresholds and delayed onset compared with normal subjects. Ipsilateral responses in biceps were smaller, with higher thresholds and delayed onsets relative to contralateral responses. Subthreshold corticospinal conditioning of the stretch reflex of biceps and quadriceps was abnormal in both hemizygous males and carrier females suggesting there may also be a reduced projection to inhibitory interneurones. Histological examination of post-mortem material from a 2-week-old male with an L1CAM mutation revealed normal corticospinal decussation and axonal projections to lumbar spinal segments. These data support a role for L1CAM in corticospinal tract development in hemizygous males and 'carrier' females, but do not support a critical role for L1CAM in corticospinal axonal guidance.
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Affiliation(s)
- C B Dobson
- Developmental Neuroscience, Department of Child Health, University of Newcastle upon Tyne, UK
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