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McEwan F, Glazier JD, Hager R. The impact of maternal immune activation on embryonic brain development. Front Neurosci 2023; 17:1146710. [PMID: 36950133 PMCID: PMC10025352 DOI: 10.3389/fnins.2023.1146710] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/15/2023] [Indexed: 03/08/2023] Open
Abstract
The adult brain is a complex structure with distinct functional sub-regions, which are generated from an initial pool of neural epithelial cells within the embryo. This transition requires a number of highly coordinated processes, including neurogenesis, i.e., the generation of neurons, and neuronal migration. These take place during a critical period of development, during which the brain is particularly susceptible to environmental insults. Neurogenesis defects have been associated with the pathogenesis of neurodevelopmental disorders (NDDs), such as autism spectrum disorder and schizophrenia. However, these disorders have highly complex multifactorial etiologies, and hence the underlying mechanisms leading to aberrant neurogenesis continue to be the focus of a significant research effort and have yet to be established. Evidence from epidemiological studies suggests that exposure to maternal infection in utero is a critical risk factor for NDDs. To establish the biological mechanisms linking maternal immune activation (MIA) and altered neurodevelopment, animal models have been developed that allow experimental manipulation and investigation of different developmental stages of brain development following exposure to MIA. Here, we review the changes to embryonic brain development focusing on neurogenesis, neuronal migration and cortical lamination, following MIA. Across published studies, we found evidence for an acute proliferation defect in the embryonic MIA brain, which, in most cases, is linked to an acceleration in neurogenesis, demonstrated by an increased proportion of neurogenic to proliferative divisions. This is accompanied by disrupted cortical lamination, particularly in the density of deep layer neurons, which may be a consequence of the premature neurogenic shift. Although many aspects of the underlying pathways remain unclear, an altered epigenome and mitochondrial dysfunction are likely mechanisms underpinning disrupted neurogenesis in the MIA model. Further research is necessary to delineate the causative pathways responsible for the variation in neurogenesis phenotype following MIA, which are likely due to differences in timing of MIA induction as well as sex-dependent variation. This will help to better understand the underlying pathogenesis of NDDs, and establish therapeutic targets.
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Galindo-Riera N, Newbold SA, Sledziowska M, Llinares-Benadero C, Griffiths J, Mire E, Martinez-Garay I. Cellular and Behavioral Characterization of Pcdh19 Mutant Mice: subtle Molecular Changes, Increased Exploratory Behavior and an Impact of Social Environment. eNeuro 2021; 8:ENEURO. [PMID: 34272258 DOI: 10.1523/ENEURO.0510-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 05/15/2021] [Accepted: 06/24/2021] [Indexed: 01/01/2023] Open
Abstract
Mutations in the X-linked cell adhesion protein PCDH19 lead to seizures, cognitive impairment, and other behavioral comorbidities when present in a mosaic pattern. Neither the molecular mechanisms underpinning this disorder nor the function of PCDH19 itself are well understood. By combining RNA in situ hybridization with immunohistochemistry and analyzing single-cell RNA sequencing datasets, we reveal Pcdh19 expression in cortical interneurons and provide a first account of the subtypes of neurons expressing Pcdh19/PCDH19, both in the mouse and the human cortex. Our quantitative analysis of the Pcdh19 mutant mouse exposes subtle changes in cortical layer composition, with no major alterations of the main axonal tracts. In addition, Pcdh19 mutant animals, particularly females, display preweaning behavioral changes, including reduced anxiety and increased exploratory behavior. Importantly, our experiments also reveal an effect of the social environment on the behavior of wild-type littermates of Pcdh19 mutant mice, which show alterations when compared with wild-type animals not housed with mutants.
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3
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Sokpor G, Kerimoglu C, Nguyen H, Pham L, Rosenbusch J, Wagener R, Nguyen HP, Fischer A, Staiger JF, Tuoc T. Loss of BAF Complex in Developing Cortex Perturbs Radial Neuronal Migration in a WNT Signaling-Dependent Manner. Front Mol Neurosci 2021; 14:687581. [PMID: 34220450 PMCID: PMC8243374 DOI: 10.3389/fnmol.2021.687581] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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] [Received: 03/29/2021] [Accepted: 05/20/2021] [Indexed: 12/22/2022] Open
Abstract
Radial neuronal migration is a key neurodevelopmental event indispensable for proper cortical laminar organization. Cortical neurons mainly use glial fiber guides, cell adhesion dynamics, and cytoskeletal remodeling, among other discrete processes, to radially trek from their birthplace to final layer positions. Dysregulated radial migration can engender cortical mis-lamination, leading to neurodevelopmental disorders. Epigenetic factors, including chromatin remodelers have emerged as formidable regulators of corticogenesis. Notably, the chromatin remodeler BAF complex has been shown to regulate several aspects of cortical histogenesis. Nonetheless, our understanding of how BAF complex regulates neuronal migration is limited. Here, we report that BAF complex is required for neuron migration during cortical development. Ablation of BAF complex in the developing mouse cortex caused alteration in the cortical gene expression program, leading to loss of radial migration-related factors critical for proper cortical layer formation. Of note, BAF complex inactivation in cortex caused defective neuronal polarization resulting in diminished multipolar-to-bipolar transition and eventual disruption of radial migration of cortical neurons. The abnormal radial migration and cortical mis-lamination can be partly rescued by downregulating WNT signaling hyperactivity in the BAF complex mutant cortex. By implication, the BAF complex modulates WNT signaling to establish the gene expression program required for glial fiber-dependent neuronal migration, and cortical lamination. Overall, BAF complex has been identified to be crucial for cortical morphogenesis through instructing multiple aspects of radial neuronal migration in a WNT signaling-dependent manner.
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Affiliation(s)
- Godwin Sokpor
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
| | - Cemil Kerimoglu
- German Center for Neurodegenerative Diseases, Göttingen, Germany
| | - Huong Nguyen
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Faculty of Biotechnology, Thai Nguyen University of Sciences, Thai Nguyen, Vietnam
| | - Linh Pham
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
| | - Joachim Rosenbusch
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany
| | - Robin Wagener
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Neurology, University Medical Center Heidelberg, Heidelberg, Germany.,Neurooncology Clinical Cooperation Unit, German Cancer Research Center, Heidelberg, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
| | - Andre Fischer
- German Center for Neurodegenerative Diseases, Göttingen, Germany.,Department for Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Jochen F Staiger
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany
| | - Tran Tuoc
- Institute for Neuroanatomy, University Medical Center Goettingen, Göttingen, Germany.,Department of Human Genetics, Ruhr University of Bochum, Bochum, Germany
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4
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Liu Y, Bergmann T, Mori Y, Peralvo Vidal JM, Pihl M, Vasistha NA, Thomsen PD, Seemann SE, Gorodkin J, Hyttel P, Khodosevich K, Witter MP, Hall VJ. Development of the Entorhinal Cortex Occurs via Parallel Lamination During Neurogenesis. Front Neuroanat 2021; 15:663667. [PMID: 34025365 PMCID: PMC8139189 DOI: 10.3389/fnana.2021.663667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 02/03/2021] [Accepted: 04/08/2021] [Indexed: 11/13/2022] Open
Abstract
The entorhinal cortex (EC) is the spatial processing center of the brain and structurally is an interface between the three layered paleocortex and six layered neocortex, known as the periarchicortex. Limited studies indicate peculiarities in the formation of the EC such as early emergence of cells in layers (L) II and late deposition of LIII, as well as divergence in the timing of maturation of cell types in the superficial layers. In this study, we examine developmental events in the entorhinal cortex using an understudied model in neuroanatomy and development, the pig and supplement the research with BrdU labeling in the developing mouse EC. We determine the pig serves as an excellent anatomical model for studying human neurogenesis, given its long gestational length, presence of a moderate sized outer subventricular zone and early cessation of neurogenesis during gestation. Immunohistochemistry identified prominent clusters of OLIG2+ oligoprogenitor-like cells in the superficial layers of the lateral EC (LEC) that are sparser in the medial EC (MEC). These are first detected in the subplate during the early second trimester. MRI analyses reveal an acceleration of EC growth at the end of the second trimester. BrdU labeling of the developing MEC, shows the deeper layers form first and prior to the superficial layers, but the LV/VI emerges in parallel and the LII/III emerges later, but also in parallel. We coin this lamination pattern parallel lamination. The early born Reln+ stellate cells in the superficial layers express the classic LV marker, Bcl11b (Ctip2) and arise from a common progenitor that forms the late deep layer LV neurons. In summary, we characterize the developing EC in a novel animal model and outline in detail the formation of the EC. We further provide insight into how the periarchicortex forms in the brain, which differs remarkably to the inside-out lamination of the neocortex.
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Affiliation(s)
- Yong Liu
- Group of Brain Development and Disease, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tobias Bergmann
- Group of Brain Development and Disease, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yuki Mori
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Juan Miguel Peralvo Vidal
- Group of Brain Development and Disease, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria Pihl
- Disease Stem Cell Models and Embryology, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Navneet A. Vasistha
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Preben Dybdahl Thomsen
- Disease Stem Cell Models and Embryology, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stefan E. Seemann
- Center for non-coding RNA in Technology and Health, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jan Gorodkin
- Center for non-coding RNA in Technology and Health, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Poul Hyttel
- Disease Stem Cell Models and Embryology, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Konstantin Khodosevich
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Menno P. Witter
- Kavli Institute for Systems Neuroscience, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Vanessa Jane Hall
- Group of Brain Development and Disease, Section Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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5
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Geisler SM, Benedetti A, Schöpf CL, Schwarzer C, Stefanova N, Schwartz A, Obermair GJ. Phenotypic Characterization and Brain Structure Analysis of Calcium Channel Subunit α 2δ-2 Mutant (Ducky) and α 2δ Double Knockout Mice. Front Synaptic Neurosci 2021; 13:634412. [PMID: 33679366 PMCID: PMC7933509 DOI: 10.3389/fnsyn.2021.634412] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/11/2021] [Indexed: 01/19/2023] Open
Abstract
Auxiliary α2δ subunits of voltage-gated calcium channels modulate channel trafficking, current properties, and synapse formation. Three of the four isoforms (α2δ-1, α2δ-2, and α2δ-3) are abundantly expressed in the brain; however, of the available knockout models, only α2δ-2 knockout or mutant mice display an obvious abnormal neurological phenotype. Thus, we hypothesize that the neuronal α2δ isoforms may have partially specific as well as redundant functions. To address this, we generated three distinct α2δ double knockout mouse models by crossbreeding single knockout (α2δ-1 and -3) or mutant (α2δ-2/ducky) mice. Here, we provide a first phenotypic description and brain structure analysis. We found that genotypic distribution of neonatal litters in distinct α2δ-1/-2, α2δ-1/-3, and α2δ-2/-3 breeding combinations did not conform to Mendel's law, suggesting premature lethality of single and double knockout mice. Notably, high occurrences of infant mortality correlated with the absence of specific α2δ isoforms (α2Δ-2 > α2δ-1 > α2δ-3), and was particularly observed in cages with behaviorally abnormal parenting animals of α2δ-2/-3 cross-breedings. Juvenile α2δ-1/-2 and α2δ-2/-3 double knockout mice displayed a waddling gate similar to ducky mice. However, in contrast to ducky and α2δ-1/-3 double knockout animals, α2δ-1/-2 and α2δ-2/-3 double knockout mice showed a more severe disease progression and highly impaired development. The observed phenotypes within the individual mouse lines may be linked to differences in the volume of specific brain regions. Reduced cortical volume in ducky mice, for example, was associated with a progressively decreased space between neurons, suggesting a reduction of total synaptic connections. Taken together, our findings show that α2δ subunits differentially regulate premature survival, postnatal growth, brain development, and behavior, suggesting specific neuronal functions in health and disease.
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Affiliation(s)
- Stefanie M. Geisler
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Ariane Benedetti
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Clemens L. Schöpf
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Nadia Stefanova
- Division of Neurobiology, Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Arnold Schwartz
- Department of Pharmacology and Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Gerald J. Obermair
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria
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6
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Wu S, Wei T, Fan W, Wang Y, Li C, Deng J. Cell cycle during neuronal migration and neo cortical lamination. Int J Dev Neurosci 2021; 81:209-219. [PMID: 33448039 DOI: 10.1002/jdn.10091] [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: 11/20/2020] [Revised: 12/30/2020] [Accepted: 01/06/2021] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVES In order to understand the relationships between neocortical lamination and cell cycle, various cells, such as neural stem cell, migrating postmitotic neuron, Cajal-Retzius (CR) cell, and mature pyramidal cell in various cell phases were investigated in mouse cortices. METHODS With mouse neocortex and hippocampus, the immunofluorescent labeling, BrdU assay, and DiI tracing technique were implemented in the study. RESULTS (1) During mouse development, the neocortex expressed different proteins, such as FOXP2, CDP, and Nestin, which could be used as the markers for cortical lamination. (2) The neural stem cells were mainly located in the subventricular zone, with the expressions of Nestin, Cyclin A2, Cyclin E1, and CDT1, suggesting that they were in the repeated cell cycle. Furthermore, the migrating neurons in the neocortex were Cyclin D1- (G1 phase-specific marker) positive, suggesting that they were in the G1 phase. However, Pyramidal cells that developed from postmitotic migrating neurons and settled in the cortical plate were Cyclin D1- negative, suggesting that they were in the G0 phase. (3) Reelin positive CR cells appeared in the molecular layer of the neocortex in early embryonic day (E10), which could express Cyclin A2, Cyclin E1, and CDT1 as pyramidal cells, but not Cyclin D1, suggesting that they may have exited the cell cycle and entered the G0 phase. CONCLUSION The neural migration, neural proliferation, and cell cycle alterations play an important role during cortical lamination. During the cortical development and lamination, the neural stem cells and migrating postmitotic neurons are in different cell cycle phases, but pyramidal cells and CR cells have exited the cell cycle.
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Affiliation(s)
- Shanshan Wu
- National Health Commission, Key Laboratory of Birth Defect Prevention, Henan Scientific and Technical Institute of Reproductive Health, Zhengzhou, China.,School of Nursing and Health, Henan University, Kaifeng, China
| | - Tingting Wei
- National Health Commission, Key Laboratory of Birth Defect Prevention, Henan Scientific and Technical Institute of Reproductive Health, Zhengzhou, China
| | - Wenjuan Fan
- Laboratory of molecular medicine, Luohe Medical College, Luohe, China
| | - Yanli Wang
- National Health Commission, Key Laboratory of Birth Defect Prevention, Henan Scientific and Technical Institute of Reproductive Health, Zhengzhou, China
| | - Chaojie Li
- National Health Commission, Key Laboratory of Birth Defect Prevention, Henan Scientific and Technical Institute of Reproductive Health, Zhengzhou, China
| | - Jinbo Deng
- National Health Commission, Key Laboratory of Birth Defect Prevention, Henan Scientific and Technical Institute of Reproductive Health, Zhengzhou, China
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7
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Shu P, Wu C, Ruan X, Liu W, Hou L, Fu H, Wang M, Liu C, Zeng Y, Chen P, Yin B, Yuan J, Qiang B, Peng X, Zhong W. Opposing Gradients of MicroRNA Expression Temporally Pattern Layer Formation in the Developing Neocortex. Dev Cell 2019; 49:764-785.e4. [PMID: 31080058 DOI: 10.1016/j.devcel.2019.04.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 11/08/2018] [Accepted: 04/07/2019] [Indexed: 12/24/2022]
Abstract
The precisely timed generation of different neuronal types is a hallmark of development from invertebrates to vertebrates. In the developing mammalian neocortex, neural stem cells change competence over time to sequentially produce six layers of functionally distinct neurons. Here, we report that microRNAs (miRNAs) are dispensable for stem-cell self-renewal and neuron production but essential for timing neocortical layer formation and specifying laminar fates. Specifically, as neurogenesis progresses, stem cells reduce miR-128 expression and miR-9 activity but steadily increase let-7 expression, whereas neurons initially maintain the differences in miRNA expression present at birth. Moreover, miR-128, miR-9, and let-7 are functionally distinct; capable of specifying neurons for layer VI and layer V and layers IV, III, and II, respectively; and transiently altering their relative levels of expression can modulate stem-cell competence in a neurogenic-stage-specific manner to shift neuron production between earlier-born and later-born fates, partly by temporally regulating a neurogenesis program involving Hmga2.
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Affiliation(s)
- Pengcheng Shu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Chao Wu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Xiangbin Ruan
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Wei Liu
- Department of Anatomy and Histology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Lin Hou
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Hongye Fu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Ming Wang
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Chang Liu
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Yi Zeng
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Pan Chen
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Bin Yin
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Jiangang Yuan
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Boqin Qiang
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Xiaozhong Peng
- The State Key Laboratory of Medical Molecular Biology, Neuroscience Center, Medical Primates Research Center and Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China; Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
| | - Weimin Zhong
- Department of Molecular, Cellular, and Developmental Biology, Yale University, P.O. Box 208103, New Haven, CT 06520, USA.
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8
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Westerberg JA, Cox MA, Dougherty K, Maier A. V1 microcircuit dynamics: altered signal propagation suggests intracortical origins for adaptation in response to visual repetition. J Neurophysiol 2019; 121:1938-1952. [PMID: 30917065 PMCID: PMC6589708 DOI: 10.1152/jn.00113.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [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] [Received: 02/19/2019] [Revised: 03/25/2019] [Accepted: 03/25/2019] [Indexed: 11/22/2022] Open
Abstract
Repetitive visual stimulation profoundly changes sensory processing in the primary visual cortex (V1). We show how the associated adaptive changes are linked to an altered flow of synaptic activation across the V1 laminar microcircuit. Using repeated visual stimulation, we recorded layer-specific responses in V1 of two fixating monkeys. We found that repetition-related spiking suppression was most pronounced outside granular V1 layers that receive the main retinogeniculate input. This repetition-related response suppression was robust to alternating stimuli between the eyes, in line with the notion that repetition-related adaptation is predominantly of cortical origin. Most importantly, current source density (CSD) analysis, which provides an estimate of local net depolarization, revealed that synaptic processing during repeated stimulation was most profoundly affected within supragranular layers, which harbor the bulk of cortico-cortical connections. Direct comparison of the temporal evolution of laminar CSD and spiking activity showed that stimulus repetition first affected supragranular synaptic currents, which translated into a reduction of stimulus-evoked spiking across layers. Together, these results suggest that repetition induces an altered state of intracortical processing that underpins visual adaptation. NEW & NOTEWORTHY Our survival depends on our brains rapidly adapting to ever changing environments. A well-studied form of adaptation occurs whenever we encounter the same or similar stimuli repeatedly. We show that this repetition-related adaptation is supported by systematic changes in the flow of sensory activation across the laminar cortical microcircuitry of primary visual cortex. These results demonstrate how adaptation impacts neuronal interactions across cortical circuits.
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Affiliation(s)
- Jacob A Westerberg
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, and Vanderbilt Vision Research Center, Vanderbilt University , Nashville, Tennessee
| | - Michele A Cox
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, and Vanderbilt Vision Research Center, Vanderbilt University , Nashville, Tennessee
| | - Kacie Dougherty
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, and Vanderbilt Vision Research Center, Vanderbilt University , Nashville, Tennessee
| | - Alexander Maier
- Department of Psychology, Center for Integrative and Cognitive Neuroscience, and Vanderbilt Vision Research Center, Vanderbilt University , Nashville, Tennessee
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9
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Abstract
The development of the cerebral cortex requires complex sequential processes that have to be precisely orchestrated. The localization and timing of neuronal progenitor proliferation and of neuronal migration define the identity, laminar positioning, and specific connectivity of each single cortical neuron. Alterations at any step of this organized series of events—due to genetic mutations or environmental factors—lead to defined brain pathologies collectively known as malformations of cortical development (MCDs), which are now recognized as a leading cause of drug-resistant epilepsy and intellectual disability. In this heterogeneous group of disorders, macroscopic alterations of brain structure (eg, heterotopic nodules, small or absent gyri, double cortex) can be recognized and probably subtend a general reorganization of neuronal circuits. In this review, we provide an overview of the molecular mechanisms that are implicated in the generation of genetic MCDs associated with aberrations at various steps of neurogenesis and cortical development.
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Affiliation(s)
| | | | - Antonio Falace
- Aix-Marseille University, INSERM U1249, INMED, Marseille 13009, France
| | - Carlos Cardoso
- Aix-Marseille University, INSERM U1249, INMED, Marseille 13009, France
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10
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Charvet CJ, Reep RL, Finlay BL. Evolution of cytoarchitectural landscapes in the mammalian isocortex: Sirenians (Trichechus manatus) in comparison with other mammals. J Comp Neurol 2015. [PMID: 26223206 DOI: 10.1002/cne.23864] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [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: 12/15/2022]
Abstract
The isocortex of several primates and rodents shows a systematic increase in the number of neurons per unit of cortical surface area from its rostrolateral to caudomedial border. The steepness of the gradient in neuronal number and density is positively correlated with cortical volume. The relative duration of neurogenesis along the same rostrocaudal gradient predicts a substantial fraction of this variation in neuron number and laminar position, which is produced principally from layers II-IV neurons. However, virtually all of our quantitative knowledge about total and laminar variation in cortical neuron numbers and neurogenesis comes from rodents and primates, leaving whole taxonomic groups and many intermediate-sized brains unexplored. Thus, the ubiquity in mammals of the covariation of longer cortical neurogenesis and increased cortical neuron number deriving from cortical layers II-IV is undetermined. To begin to address this gap, we examined the isocortex of the manatee using the optical disector method in sectioned tissue, and also assembled partial data from published reports of the domestic cat brain. The manatee isocortex has relatively fewer neurons per total volume, and fewer II-IV neurons than primates with equivalently sized brains. The gradient in number of neurons from the rostral to the caudal pole is intermediate between primates and rodents, and, like those species, is observed only in the upper cortical layers. The cat isocortex (Felis domesticus) shows a similar structure. Key species for further tests of the origin, ubiquity, and significance of this organizational feature are discussed.
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Affiliation(s)
- Christine J Charvet
- Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, 20052
| | - Roger L Reep
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, 32610
| | - Barbara L Finlay
- Behavioral and Evolutionary Neuroscience Group, Department of Psychology, Cornell University, Ithaca, NY, 14853
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Manuel MN, Mi D, Mason JO, Price DJ. Regulation of cerebral cortical neurogenesis by the Pax6 transcription factor. Front Cell Neurosci 2015; 9:70. [PMID: 25805971 PMCID: PMC4354436 DOI: 10.3389/fncel.2015.00070] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [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: 11/21/2014] [Accepted: 02/18/2015] [Indexed: 12/19/2022] Open
Abstract
Understanding brain development remains a major challenge at the heart of understanding what makes us human. The neocortex, in evolutionary terms the newest part of the cerebral cortex, is the seat of higher cognitive functions. Its normal development requires the production, positioning, and appropriate interconnection of very large numbers of both excitatory and inhibitory neurons. Pax6 is one of a relatively small group of transcription factors that exert high-level control of cortical development, and whose mutation or deletion from developing embryos causes major brain defects and a wide range of neurodevelopmental disorders. Pax6 is very highly conserved between primate and non-primate species, is expressed in a gradient throughout the developing cortex and is essential for normal corticogenesis. Our understanding of Pax6’s functions and the cellular processes that it regulates during mammalian cortical development has significantly advanced in the last decade, owing to the combined application of genetic and biochemical analyses. Here, we review the functional importance of Pax6 in regulating cortical progenitor proliferation, neurogenesis, and formation of cortical layers and highlight important differences between rodents and primates. We also review the pathological effects of PAX6 mutations in human neurodevelopmental disorders. We discuss some aspects of Pax6’s molecular actions including its own complex transcriptional regulation, the distinct molecular functions of its splice variants and some of Pax6’s known direct targets which mediate its actions during cortical development.
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Affiliation(s)
- Martine N Manuel
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
| | - Da Mi
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
| | - John O Mason
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
| | - David J Price
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
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Abstract
Most neurons migrate with an elongated, “bipolar” morphology, extending a long leading process that explores the environment. However, when immature projection neurons enter the intermediate zone (IZ) of the neocortex they become “multipolar”. Multipolar cells extend and retract cytoplasmic processes in different directions and move erratically—sideways, up and down. Multipolar cells extend axons while they are in the lower half of the IZ. Remarkably, the cells then resume radial migration: they reorient their centrosome and Golgi apparatus towards the pia, transform back to bipolar morphology, and commence locomotion along radial glia (RG) fibers. This reorientation implies the existence of directional signals in the IZ that are ignored during the multipolar stage but sensed after axonogenesis. In vivo genetic manipulation has implicated a variety of candidate directional signals, cell surface receptors, and signaling pathways, that may be involved in polarizing multipolar cells and stabilizing a pia-directed leading process for radial migration. Other signals are implicated in starting multipolar migration and triggering axon outgrowth. Here we review the molecules and mechanisms that regulate multipolar migration, and also discuss how multipolar migration affects the orderly arrangement of neurons in layers and columns in the developing neocortex.
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Affiliation(s)
- Jonathan A Cooper
- Fred Hutchinson Cancer Research Center, Division of Basic Sciences Seattle, Washington, USA
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13
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Abstract
Formation of a 6-layered cortical plate and axon tract patterning are key features of cerebral cortex development. Abnormalities of these processes may be the underlying cause for a range of functional disabilities seen in human neurodevelopmental disorders. To identify mouse mutants with defects in cortical lamination or corticofugal axon guidance, N-ethyl-N-nitrosourea (ENU) mutagenesis was performed using mice expressing LacZ reporter genes in layers II/III and V of the cortex (Rgs4-lacZ) or in corticofugal axons (TAG1-tau-lacZ). Four lines with abnormal cortical lamination have been identified. One of these was a splice site mutation in reelin (Reln) that results in a premature stop codon and the truncation of the C-terminal region (CTR) domain of reelin. Interestingly, this novel allele of Reln did not display cerebellar malformation or ataxia, and this is the first report of a Reln mutant without a cerebellar defect. Four lines with abnormal cortical axon development were also identified, one of which was found by whole-genome resequencing to carry a mutation in Lrp2. These findings demonstrated that the application of ENU mutagenesis to mice carrying transgenic reporters marking cortical anatomy is a sensitive and specific method to identify mutations that disrupt patterning of the developing brain.
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Affiliation(s)
- Seungshin Ha
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Rolf W Stottmann
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Divisions of Human Genetics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA and
| | - Andrew J Furley
- Department of Biomedical Science, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David R Beier
- Genetics Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA
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14
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Favero CB, Henshaw RN, Grimsley-Myers CM, Shrestha A, Beier DR, Dwyer ND. Mutation of the BiP/GRP78 gene causes axon outgrowth and fasciculation defects in the thalamocortical connections of the mammalian forebrain. J Comp Neurol 2013; 521:677-96. [PMID: 22821687 PMCID: PMC3515720 DOI: 10.1002/cne.23199] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [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] [Received: 09/15/2011] [Revised: 05/13/2012] [Accepted: 07/13/2012] [Indexed: 02/05/2023]
Abstract
Proper development of axonal connections is essential for brain function. A forward genetic screen for mice with defects in thalamocortical development previously isolated a mutant called baffled. Here we describe the axonal defects of baffled in further detail and identify a point mutation in the Hspa5 gene, encoding the endoplasmic reticulum chaperone BiP/GRP78. This hypomorphic mutation of BiP disrupts proper development of the thalamocortical axon projection and other forebrain axon tracts, as well as cortical lamination. In baffled mutant brains, a reduced number of thalamic axons innervate the cortex by the time of birth. Thalamocortical and corticothalamic axons are delayed, overfasciculated, and disorganized along their pathway through the ventral telencephalon. Furthermore, dissociated mutant neurons show reduced axon extension in vitro. Together, these findings demonstrate a sensitive requirement for the endoplasmic reticulum chaperone BiP/GRP78 during axon outgrowth and pathfinding in the developing mammalian brain.
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Affiliation(s)
- Carlita B. Favero
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Rasha N. Henshaw
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | | | - Ayushma Shrestha
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
| | - David R. Beier
- Division of Genetics, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Noelle D. Dwyer
- Department of Cell Biology, University of Virginia, Charlottesville, VA, 22908, USA
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Alvarez-Dolado M, Ruiz M, Del Río JA, Alcántara S, Burgaya F, Sheldon M, Nakajima K, Bernal J, Howell BW, Curran T, Soriano E, Muñoz A. Thyroid hormone regulates reelin and dab1 expression during brain development. J Neurosci 1999; 19:6979-93. [PMID: 10436054 PMCID: PMC6782883] [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] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/1999] [Revised: 05/11/1999] [Accepted: 05/21/1999] [Indexed: 02/13/2023] Open
Abstract
The reelin and dab1 genes are necessary for appropriate neuronal migration and lamination during brain development. Since these processes are controlled by thyroid hormone, we studied the effect of thyroid hormone deprivation and administration on the expression of reelin and dab1. As shown by Northern analysis, in situ hybridization, and immunohistochemistry studies, hypothyroid rats expressed decreased levels of reelin RNA and protein during the perinatal period [embryonic day 18 (E18) and postnatal day 0 (P0)]. The effect was evident in Cajal-Retzius cells of cortex layer I, as well as in layers V/VI, hippocampus, and granular neurons of the cerebellum. At later ages, however, Reelin was more abundant in the cortex, hippocampus, cerebellum, and olfactory bulb of hypothyroid rats (P5), and no differences were detected at P15. Conversely, Dab1 levels were higher at P0, and lower at P5 in hypothyroid animals. In line with these results, reelin RNA and protein levels were higher in cultured hippocampal slices from P0 control rats compared to those from hypothyroid animals. Significantly, thyroid-dependent regulation of reelin and dab1 was confirmed in vivo and in vitro by hormone treatment of hypothyroid rats and organotypic cultures, respectively. In both cases, thyroid hormone led to an increase in reelin expression. Our data suggest that the effects of thyroid hormone on neuronal migration may be in part mediated through the control of reelin and dab1 expression during brain ontogenesis.
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Affiliation(s)
- M Alvarez-Dolado
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28029 Madrid, Spain
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