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Rhodes CT, Asokumar D, Sohn M, Naskar S, Elisha L, Stevenson P, Lee DR, Zhang Y, Rocha PP, Dale RK, Lee S, Petros TJ. Loss of Ezh2 in the medial ganglionic eminence alters interneuron fate, cell morphology and gene expression profiles. Front Cell Neurosci 2024; 18:1334244. [PMID: 38419656 PMCID: PMC10899338 DOI: 10.3389/fncel.2024.1334244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/31/2024] [Indexed: 03/02/2024] Open
Abstract
Introduction Enhancer of zeste homolog 2 (Ezh2) is responsible for trimethylation of histone 3 at lysine 27 (H3K27me3), resulting in repression of gene expression. Here, we explore the role of Ezh2 in forebrain GABAergic interneuron development. Methods We removed Ezh2 in the MGE by generating Nkx2-1Cre;Ezh2 conditional knockout mice. We then characterized changes in MGE-derived interneuron fate and electrophysiological properties in juvenile mice, as well as alterations in gene expression, chromatin accessibility and histone modifications in the MGE. Results Loss of Ezh2 increases somatostatin-expressing (SST+) and decreases parvalbumin-expressing (PV+) interneurons in the forebrain. We observe fewer MGE-derived interneurons in the first postnatal week, indicating reduced interneuron production. Intrinsic electrophysiological properties in SST+ and PV+ interneurons are normal, but PV+ interneurons display increased axonal complexity in Ezh2 mutant mice. Single nuclei multiome analysis revealed differential gene expression patterns in the embryonic MGE that are predictive of these cell fate changes. Lastly, CUT&Tag analysis revealed that some genomic loci are particularly resistant or susceptible to shifts in H3K27me3 levels in the absence of Ezh2, indicating differential selectivity to epigenetic perturbation. Discussion Thus, loss of Ezh2 in the MGE alters interneuron fate, morphology, and gene expression and regulation. These findings have important implications for both normal development and potentially in disease etiologies.
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Affiliation(s)
- Christopher T Rhodes
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Dhanya Asokumar
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
- Unit on Genome Structure and Regulation, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Mira Sohn
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Shovan Naskar
- Unit on Functional Neural Circuits, National Institute of Mental Health (NIMH), NIH, Bethesda, MD, United States
| | - Lielle Elisha
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Parker Stevenson
- Unit on Functional Neural Circuits, National Institute of Mental Health (NIMH), NIH, Bethesda, MD, United States
| | - Dongjin R Lee
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Yajun Zhang
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Pedro P Rocha
- Unit on Genome Structure and Regulation, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
- National Cancer Institute (NCI), NIH, Bethesda, MD, United States
| | - Ryan K Dale
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
| | - Soohyun Lee
- Unit on Functional Neural Circuits, National Institute of Mental Health (NIMH), NIH, Bethesda, MD, United States
| | - Timothy J Petros
- Unit on Cellular and Molecular Neurodevelopment, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, MD, United States
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Hijazi S, Smit AB, van Kesteren RE. Fast-spiking parvalbumin-positive interneurons in brain physiology and Alzheimer's disease. Mol Psychiatry 2023; 28:4954-4967. [PMID: 37419975 PMCID: PMC11041664 DOI: 10.1038/s41380-023-02168-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/26/2023] [Accepted: 06/26/2023] [Indexed: 07/09/2023]
Abstract
Fast-spiking parvalbumin (PV) interneurons are inhibitory interneurons with unique morphological and functional properties that allow them to precisely control local circuitry, brain networks and memory processing. Since the discovery in 1987 that PV is expressed in a subset of fast-spiking GABAergic inhibitory neurons, our knowledge of the complex molecular and physiological properties of these cells has been expanding. In this review, we highlight the specific properties of PV neurons that allow them to fire at high frequency and with high reliability, enabling them to control network oscillations and shape the encoding, consolidation and retrieval of memories. We next discuss multiple studies reporting PV neuron impairment as a critical step in neuronal network dysfunction and cognitive decline in mouse models of Alzheimer's disease (AD). Finally, we propose potential mechanisms underlying PV neuron dysfunction in AD and we argue that early changes in PV neuron activity could be a causal step in AD-associated network and memory impairment and a significant contributor to disease pathogenesis.
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Affiliation(s)
- Sara Hijazi
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Ronald E van Kesteren
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands.
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Gonda S, Riedel C, Reiner A, Köhler I, Wahle P. Axons of cortical basket cells originating from dendrites develop higher local complexity than axons emerging from basket cell somata. Development 2023; 150:dev202305. [PMID: 37902086 PMCID: PMC10690106 DOI: 10.1242/dev.202305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/24/2023] [Indexed: 10/31/2023]
Abstract
Neuronal differentiation is regulated by neuronal activity. Here, we analyzed dendritic and axonal growth of Basket cells (BCs) and non-Basket cells (non-BCs) using sparse transfection of channelrhodopsin-YFP and repetitive optogenetic stimulation in slice cultures of rat visual cortex. Neocortical interneurons often display axon-carrying dendrites (AcDs). We found that the AcDs of BCs and non-BCs were, on average, the most complex dendrites. Further, the AcD configuration had an influence on BC axonal development. Axons originating from an AcD formed denser arborizations with more terminal endings within the dendritic field of the parent cell. Intriguingly, this occurred already in unstimulated BCs, and complexity was not increased further by optogenetic stimulation. However, optogenetic stimulation exerted a growth-promoting effect on axons emerging from BC somata. The axons of non-BCs neither responded to the AcD configuration nor to the optogenetic stimulation. The results suggest that the formation of locally dense BC plexuses is regulated by spontaneous activity. Moreover, in the AcD configuration, the AcD and the axon it carries mutually support each other's growth.
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Affiliation(s)
- Steffen Gonda
- Developmental Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Christian Riedel
- Developmental Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Andreas Reiner
- Cellular Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Ina Köhler
- Developmental Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Petra Wahle
- Developmental Neurobiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany
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Druga R, Salaj M, Al-Redouan A. Parvalbumin - Positive Neurons in the Neocortex: A Review. Physiol Res 2023; 72:S173-S191. [PMID: 37565421 PMCID: PMC10660579 DOI: 10.33549/physiolres.935005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/02/2023] [Indexed: 12/01/2023] Open
Abstract
The calcium binding protein parvalbumin (PV) in the mammalian neocortex is expressed in a subpopulation of cortical GABAergic inhibitory interneurons. PV - producing interneurons represent the largest subpopulation of neocortical inhibitory cells, exhibit mutual chemical and electrical synaptic contacts and are well known to generate gamma oscillation. This review summarizes basic data of the distribution, afferent and efferent connections and physiological properties of parvalbumin expressing neurons in the neocortex. Basic data about participation of PV-positive neurons in cortical microcircuits are presented. Autaptic connections, metabolism and perineuronal nets (PNN) of PV positive neurons are also discussed.
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Affiliation(s)
- R Druga
- Department of Anatomy, 2nd Medical Faculty, Charles University Prague, Czech Republic.
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Tian D, Izumi SI. Different effects of I-wave periodicity repetitive TMS on motor cortex interhemispheric interaction. Front Neurosci 2023; 17:1079432. [PMID: 37457007 PMCID: PMC10349661 DOI: 10.3389/fnins.2023.1079432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Background Activity of the neural circuits in the human motor cortex can be probed using transcranial magnetic stimulation (TMS). Changing TMS-induced current direction recruits different cortical neural circuits. I-wave periodicity repetitive TMS (iTMS) substantially modulates motor cortex excitability through neural plasticity, yet its effect on interhemispheric interaction remains unclear. Objective To explore the modulation of interhemispheric interaction by iTMS applied in different current directions. Materials and Methods Twenty right-handed healthy young volunteers (aged 27.5 ± 5.0 years) participated in this study with three visits. On each visit, iTMS in posterior-anterior/anterior-posterior direction (PA-/AP-iTMS) or sham-iTMS was applied to the right hemisphere, with corticospinal excitability and intracortical facilitation of the non-stimulated left hemisphere evaluated at four timepoints. Ipsilateral silent period was also measured at each timepoint probing interhemispheric inhibition (IHI). Results PA- and AP-iTMS potentiated cortical excitability concurrently in the stimulated right hemisphere. Corticospinal excitability of the non-stimulated left hemisphere increased 10 min after both PA- and AP-iTMS intervention, with a decrease in short-interval intracortical facilitation (SICF) observed in AP-iTMS only. Immediately after the intervention, PA-iTMS tilted the IHI balance toward inhibiting the non-stimulated hemisphere, while AP-iTMS shifted the balance toward the opposite direction. Conclusions Our findings provide systematic evidence on the plastic modulation of interhemispheric interaction by PA- and AP-iTMS. We show that iTMS induces an interhemispheric facilitatory effect, and that PA- and AP-iTMS differs in modulating interhemispheric inhibition.
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Affiliation(s)
- Dongting Tian
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shin-Ichi Izumi
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
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Sobierajski E, Lauer G, Czubay K, Grabietz H, Beemelmans C, Beemelmans C, Meyer G, Wahle P. Development of myelin in fetal and postnatal neocortex of the pig, the European wild boar Sus scrofa. Brain Struct Funct 2023; 228:947-966. [PMID: 37000250 PMCID: PMC10147765 DOI: 10.1007/s00429-023-02633-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/15/2023] [Indexed: 04/01/2023]
Abstract
Myelination of the neocortex of altricial species is mostly a postnatal event, and the appearance of myelin has been associated with the end of the critical period for ocular dominance plasticity in rodent visual cortex. Due to their precocality, ungulates may tell a different story. Here, we analyzed the development of PDGFRα positive oligodendrocyte precursor cells and expression of myelin proteins in the laminar compartments of fetal and postnatal porcine cortex from E45 onwards. Precursor cell density initially increased and then decreased but remained present at P90. MAG and MBP staining were detectable at E70 in subventricular zone and deep white matter, ascending into gyral white matter at E85, and into the gray matter and marginal zone at E100 (birth in pig at E114). Protein blots confirmed the declining expression of PDGFRα from E65 onwards, and the increase of MBP and MAG expression from E80 onwards. Somatosensory input elicited by spontaneous activity is considered important for the formation of the body representation. Indeed, PDGFRα, MBP and MAG expression started earlier in somatosensory than in visual cortex. Taken together, myelination proceeded in white and gray matter and marginal zone of pig cortex before birth with an areal-specific time course, and an almost mature pattern was present at P5 in visual cortex.
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Affiliation(s)
- Eric Sobierajski
- Faculty of Biology and Biotechnology, Developmental Neurobiology, Ruhr University Bochum, 44870, Bochum, Germany
| | - German Lauer
- Faculty of Biology and Biotechnology, Developmental Neurobiology, Ruhr University Bochum, 44870, Bochum, Germany
| | - Katrin Czubay
- Faculty of Biology and Biotechnology, Developmental Neurobiology, Ruhr University Bochum, 44870, Bochum, Germany
| | - Hannah Grabietz
- Faculty of Biology and Biotechnology, Developmental Neurobiology, Ruhr University Bochum, 44870, Bochum, Germany
| | - Christa Beemelmans
- Regionalverband Ruhr Grün, Forsthof Üfter Mark, Forsthausweg 306, 46514, Schermbeck, Germany
| | - Christoph Beemelmans
- Regionalverband Ruhr Grün, Forsthof Üfter Mark, Forsthausweg 306, 46514, Schermbeck, Germany
| | - Gundela Meyer
- Department of Basic Medical Science, Faculty of Medicine, University of La Laguna, 38200, Santa Cruz de Tenerife, Tenerife, Spain
| | - Petra Wahle
- Faculty of Biology and Biotechnology, Developmental Neurobiology, Ruhr University Bochum, 44870, Bochum, Germany.
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ARRAY TOMOGRAPHY: 15 YEARS OF SYNAPTIC ANALYSIS. Neuronal Signal 2022; 6:NS20220013. [PMID: 36187224 PMCID: PMC9512143 DOI: 10.1042/ns20220013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/31/2022] [Accepted: 09/06/2022] [Indexed: 11/25/2022] Open
Abstract
Synapses are minuscule, intricate structures crucial for the correct communication between neurons. In the 125 years since the term synapse was first coined, we have advanced a long way when it comes to our understanding of how they work and what they do. Most of the fundamental discoveries have been invariably linked to advances in technology. However, due to their size, delicate structural integrity and their sheer number, our knowledge of synaptic biology has remained somewhat elusive and their role in neurodegenerative diseases still remains largely unknown. Here, we briefly discuss some of the imaging technologies used to study synapses and focus on the utility of the high-resolution imaging technique array tomography (AT). We introduce the AT technique and highlight some of the ways it is utilised with a particular focus on its power for analysing synaptic composition and pathology in human post-mortem tissue. We also discuss some of the benefits and drawbacks of techniques for imaging synapses and highlight some recent advances in the study of form and function by combining physiology and high-resolution synaptic imaging.
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Rah JC, Choi JH. Finding Needles in a Haystack with Light: Resolving the Microcircuitry of the Brain with Fluorescence Microscopy. Mol Cells 2022; 45:84-92. [PMID: 35236783 PMCID: PMC8907002 DOI: 10.14348/molcells.2022.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 12/20/2021] [Indexed: 11/30/2022] Open
Abstract
To understand the microcircuitry of the brain, the anatomical and functional connectivity among neurons must be resolved. One of the technical hurdles to achieving this goal is that the anatomical connections, or synapses, are often smaller than the diffraction limit of light and thus are difficult to resolve by conventional microscopy, while the microcircuitry of the brain is on the scale of 1 mm or larger. To date, the gold standard method for microcircuit reconstruction has been electron microscopy (EM). However, despite its rapid development, EM has clear shortcomings as a method for microcircuit reconstruction. The greatest weakness of this method is arguably its incompatibility with functional and molecular analysis. Fluorescence microscopy, on the other hand, is readily compatible with numerous physiological and molecular analyses. We believe that recent advances in various fluorescence microscopy techniques offer a new possibility for reliable synapse detection in large volumes of neural circuits. In this minireview, we summarize recent advances in fluorescence-based microcircuit reconstruction. In the same vein as these studies, we introduce our recent efforts to analyze the long-range connectivity among brain areas and the subcellular distribution of synapses of interest in relatively large volumes of cortical tissue with array tomography and superresolution microscopy.
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Affiliation(s)
- Jong-Cheol Rah
- Laboratory of Neurophysiology, Korea Brain Research Institute, Daegu 41062, Korea
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology, Daegu 42988, Korea
| | - Joon Ho Choi
- Laboratory of Neurophysiology, Korea Brain Research Institute, Daegu 41062, Korea
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