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Coronin 2B Regulates Neuronal Migration via Rac1-Dependent Multipolar-Bipolar Transition. J Neurosci 2023; 43:211-220. [PMID: 36639906 PMCID: PMC9838710 DOI: 10.1523/jneurosci.1087-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/24/2022] [Accepted: 11/19/2022] [Indexed: 12/12/2022] Open
Abstract
In the developing cortex, excitatory neurons migrate along the radial fibers to their final destinations and build up synaptic connection with each other to form functional circuitry. The shaping of neuronal morphologies by actin cytoskeleton dynamics is crucial for neuronal migration. However, it is largely unknown how the distribution and assembly of the F-actin cytoskeleton are coordinated. In the present study, we found that an actin regulatory protein, coronin 2B, is indispensable for the transition from a multipolar to bipolar morphology during neuronal migration in ICR mice of either sex. Loss of coronin 2B led to heterotopic accumulation of migrating neurons in the intermediate zone along with reduced dendritic complexity and aberrant neuronal activity in the cortical plate. This was accompanied by increased seizure susceptibility, suggesting the malfunction of cortical development in coronin 2B-deficient brains. Coronin 2B knockdown disrupted the distribution of the F-actin cytoskeleton at the leading processes, while the migration defect in coronin 2B-deficient neurons was partially rescued by overexpression of Rac1 and its downstream actin-severing protein, cofilin. Our results collectively reveal the physiological function of coronin 2B during neuronal migration whereby it maintains the proper distribution of activated Rac1 and the F-actin cytoskeleton.SIGNIFICANCE STATEMENT Deficits in neuronal migration during cortical development result in various neurodevelopmental disorders (e.g., focal cortical dysplasia, periventricular heterotopia, epilepsy, etc.). Most signaling pathways that control neuronal migration process converge to regulate actin cytoskeleton dynamics. Therefore, it is important to understand how actin dynamics is coordinated in the critical processes of neuronal migration. Herein, we report that coronin 2B is a key protein that regulates neuronal migration through its ability to control the distribution of the actin cytoskeleton and its regulatory signaling protein Rac1 during the multipolar-bipolar transition in the intermediate zone, providing insights into the molecular machinery that drives the migration process of newborn neurons.
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Stanton-Turcotte D, Hsu K, Moore SA, Yamada M, Fawcett JP, Iulianella A. Mllt11 Regulates Migration and Neurite Outgrowth of Cortical Projection Neurons during Development. J Neurosci 2022; 42:3931-3948. [PMID: 35379703 PMCID: PMC9097781 DOI: 10.1523/jneurosci.0124-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/13/2022] [Accepted: 03/30/2022] [Indexed: 11/22/2022] Open
Abstract
The formation of connections within the mammalian neocortex is highly regulated by both extracellular guidance mechanisms and intrinsic gene expression programs. There are two types of cortical projection neurons (CPNs): those that project locally and interhemispherically and those that project to subcerebral structures such as the thalamus, hindbrain, and spinal cord. The regulation of cortical projection morphologies is not yet fully understood at the molecular level. Here, we report a role for Mllt11 (Myeloid/lymphoid or mixed-lineage leukemia; translocated to chromosome 11/All1 Fused Gene From Chromosome 1q) in the migration and neurite outgrowth of callosal projection neurons during mouse brain formation. We show that Mllt11 expression is exclusive to developing neurons and is enriched in the developing cortical plate (CP) during the formation of the superficial cortical layers. In cultured primary cortical neurons, Mllt11 is detected in varicosities and growth cones as well as the soma. Using conditional loss-of-function and gain-of-function analysis we show that Mllt11 is required for neuritogenesis and proper migration of upper layer CPNs. Loss of Mllt11 in the superficial cortex of male and female neonates leads to a severe reduction in fibers crossing the corpus callosum (CC), a progressive loss in the maintenance of upper layer projection neuron gene expression, and reduced complexity of dendritic arborization. Proteomic analysis revealed that Mllt11 associates with stabilized microtubules, and Mllt11 loss affected microtubule staining in callosal axons. Taken together, our findings support a role for Mllt11 in promoting the formation of mature upper-layer neuron morphologies and connectivity in the cerebral cortex.SIGNIFICANCE STATEMENT The regulation of cortical projection neuron (CPN) morphologies is an area of active investigation since the time of Cajal. Yet the molecular mechanisms of how the complex dendritic and axonal morphologies of projection neurons are formed remains incompletely understood. Although conditional mutagenesis analysis in the mouse, coupled with overexpression assays in the developing fetal brain, we show that a novel protein called Mllt11 is sufficient and necessary to regulate the dendritic and axonal characteristics of callosal projection neurons in the developing mammalian neocortex. Furthermore, we show that Mllt11 interacts with microtubules, likely accounting for its role in neuritogenesis.
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Affiliation(s)
- Danielle Stanton-Turcotte
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Karolynn Hsu
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Samantha A Moore
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Makiko Yamada
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - James P Fawcett
- Departments of Phamacology, Surgery, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
| | - Angelo Iulianella
- Department of Medical Neuroscience, and Brain Repair Centre, Faculty of Medicine, Dalhousie University. Life Science Research Institute, Halifax, Nova Scotia B3H-4R2, Canada
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3
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Phosphorylation of Focal Adhesion Kinase at Y925: Role in Glia-Dependent and Independent Migration through Regulating Cofilin and N-Cadherin. Mol Neurobiol 2022; 59:3467-3484. [PMID: 35325397 DOI: 10.1007/s12035-022-02773-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 02/16/2022] [Indexed: 10/18/2022]
Abstract
The adult neocortex is a six-layered structure, consisting of nearly continuous layers of neurons that are generated in a temporally strictly coordinated order. During development, cortical neurons originating from the ventricular zone migrate toward the Reelin-containing marginal zone in an inside-out arrangement. Focal adhesion kinase (FAK), one tyrosine kinase localizing to focal adhesions, has been shown to be phosphorylated at tyrosine 925 (Y925) by Src, an important downstream molecule of Reelin signaling. Up to date, the precise molecular mechanisms of FAK and its phosphorylation at Y925 during neuronal migration are still unclear. Combining in utero electroporation with immunohistochemistry and live imaging, we examined the function of FAK in regulating neuronal migration. We show that phosphorylated FAK is colocalized with Reelin positive Cajal-Retzius cells in the developing neocortex and hippocampus. Phosphorylation of FAK at Y925 is significantly reduced in reeler mice. Overexpression and dephosphorylation of FAK impair locomotion and translocation, resulting in migration inhibition and dislocation of both late-born and early-born neurons. These migration defects are highly correlated to the function of FAK in regulating cofilin phosphorylation and N-Cadherin expression, both are involved in Reelin signaling pathway. Thus, fine-tuned phosphorylation of focal adhesion kinase at Y925 is crucial for both glia-dependent and independent neuronal migration.
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4
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New Strategies for the Treatment of Neuropsychiatric Disorders Based on Reelin Dysfunction. Int J Mol Sci 2022; 23:ijms23031829. [PMID: 35163751 PMCID: PMC8836358 DOI: 10.3390/ijms23031829] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/31/2022] [Accepted: 02/03/2022] [Indexed: 12/16/2022] Open
Abstract
Reelin is an extracellular matrix protein that is mainly produced in Cajal-Retzius cells and controls neuronal migration, which is important for the proper formation of cortical layers in the developmental stage of the brain. In the adult brain, Reelin plays a crucial role in the regulation of N-methyl-D-aspartate receptor-dependent synaptic function, and its expression decreases postnatally. Clinical studies showed reductions in Reelin protein and mRNA expression levels in patients with psychiatric disorders; however, the causal relationship remains unclear. Reelin-deficient mice exhibit an abnormal neuronal morphology and behavior, while Reelin supplementation ameliorates learning deficits, synaptic dysfunctions, and spine loss in animal models with Reelin deficiency. These findings suggest that the neuronal deficits and brain dysfunctions associated with the down-regulated expression of Reelin are attenuated by enhancements in its expression and functions in the brain. In this review, we summarize findings on the role of Reelin in neuropsychiatric disorders and discuss potential therapeutic approaches for neuropsychiatric disorders associated with Reelin dysfunctions.
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Orcinha C, Kilias A, Paschen E, Follo M, Haas CA. Reelin Is Required for Maintenance of Granule Cell Lamination in the Healthy and Epileptic Hippocampus. Front Mol Neurosci 2021; 14:730811. [PMID: 34483838 PMCID: PMC8414139 DOI: 10.3389/fnmol.2021.730811] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/26/2021] [Indexed: 11/21/2022] Open
Abstract
One characteristic feature of mesial temporal lobe epilepsy is granule cell dispersion (GCD), a pathological widening of the granule cell layer in the dentate gyrus. The loss of the extracellular matrix protein Reelin, an important positional cue for neurons, correlates with GCD formation in MTLE patients and in rodent epilepsy models. Here, we used organotypic hippocampal slice cultures (OHSC) from transgenic mice expressing enhanced green fluorescent protein (eGFP) in differentiated granule cells (GCs) to monitor GCD formation dynamically by live cell video microscopy and to investigate the role of Reelin in this process. We present evidence that following treatment with the glutamate receptor agonist kainate (KA), eGFP-positive GCs migrated mainly toward the hilar region. In the hilus, Reelin-producing neurons were rapidly lost following KA treatment as shown in a detailed time series. Addition of recombinant Reelin fragments to the medium effectively prevented the KA-triggered movement of eGFP-positive GCs. Placement of Reelin-coated beads into the hilus of KA-treated cultures stopped the migration of GCs in a distance-dependent manner. In addition, quantitative Western blot analysis revealed that KA treatment affects the Reelin signal transduction pathway by increasing intracellular adaptor protein Disabled-1 synthesis and reducing the phosphorylation of cofilin, a downstream target of the Reelin pathway. Both events were normalized by addition of recombinant Reelin fragments. Finally, following neutralization of Reelin in healthy OHSC by incubation with the function-blocking CR-50 Reelin antibody, GCs started to migrate without any direction preference. Together, our findings demonstrate that normotopic position of Reelin is essential for the maintenance of GC lamination in the dentate gyrus and that GCD is the result of a local Reelin deficiency.
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Affiliation(s)
- Catarina Orcinha
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Antje Kilias
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg im Breisgau, Germany
| | - Enya Paschen
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.,Faculty of Biology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Marie Follo
- Lighthouse Core Facility, Department of Internal Medicine I, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany.,Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
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6
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Wang S, Li X, Zhang Q, Chai X, Wang Y, Förster E, Zhu X, Zhao S. Nyap1 Regulates Multipolar-Bipolar Transition and Morphology of Migrating Neurons by Fyn Phosphorylation during Corticogenesis. Cereb Cortex 2021; 30:929-941. [PMID: 31609430 DOI: 10.1093/cercor/bhz137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 12/20/2022] Open
Abstract
The coordination of cytoskeletal regulation is a prerequisite for proper neuronal migration during mammalian corticogenesis. Neuronal tyrosine-phosphorylated adaptor for the phosphoinositide 3-kinase 1 (Nyap1) is a member of the Nyap family of phosphoproteins, which has been studied in neuronal morphogenesis and is involved in remodeling of the actin cytoskeleton. However, the precise role of Nyap1 in neuronal migration remains unknown. Here, overexpression and knockdown of Nyap1 in the embryonic neocortex of mouse by in utero electroporation-induced abnormal morphologies and multipolar-bipolar transitions of migrating neurons. The level of phosphorylated Nyap1 was crucial for neuronal migration and morphogenesis in neurons. Furthermore, Nyap1 regulated neuronal migration as a downstream target of Fyn, a nonreceptor protein-tyrosine kinase that is a member of the Src family of kinases. Importantly, Nyap1 mediated the role of Fyn in the multipolar-bipolar transition of migrating neurons. Taken together, these results suggest that cortical radial migration is regulated by a molecular hierarchy of Fyn via Nyap1.
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Affiliation(s)
- Shuzhong Wang
- College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi 712100, PR China
| | - Xuzhao Li
- College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi 712100, PR China
| | - Qianru Zhang
- College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi 712100, PR China
| | - Xuejun Chai
- College of Basic Medicine, Xi'An Medical University, Xi'An, 710021, PR China
| | - Yi Wang
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation) and Shenzhen Key Laboratory of Food Biological Safety Control, Shenzhen Research Institute of Hong Kong Polytechnic University, Shenzhen 518057, PR China
| | - Eckart Förster
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum 44801, Germany
| | - Xiaoyan Zhu
- College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi 712100, PR China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A & F University, Yangling, Shaanxi 712100, PR China
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Takeda H, Kameo Y, Adachi T. Continuum modeling for neuronal lamination during cerebral morphogenesis considering cell migration and tissue growth. Comput Methods Biomech Biomed Engin 2020; 24:1-7. [PMID: 33290089 DOI: 10.1080/10255842.2020.1852554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/09/2020] [Accepted: 11/15/2020] [Indexed: 10/22/2022]
Abstract
For neuronal lamination during cerebral morphogenesis, later-born neurons must migrate through already-accumulated neurons. This neuronal migration is biochemically regulated by signaling molecules and mechanically affected by tissue deformation. To understand the neuronal lamination mechanisms, we constructed a continuum model of neuronal migration in a growing deformable tissue. We performed numerical analyses considering the migration promoted by signaling molecules and the tissue growth induced by neuron accumulation. The results suggest that the promoted migration and the space ensured by tissue growth are essential for neuronal lamination. The proposed model can describe the coupling of mechanical and biochemical mechanisms for neuronal lamination.
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Affiliation(s)
- Hironori Takeda
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yoshitaka Kameo
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Taiji Adachi
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan
- Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Zhu X, Wu Y, Pan J, Li C, Huang J, Cui E, Chen Z, Zhou W, Chai X, Zhao S. Neuroinflammation Induction and Alteration of Hippocampal Neurogenesis in Mice Following Developmental Exposure to Gossypol. Int J Neuropsychopharmacol 2020; 24:419-433. [PMID: 33283869 PMCID: PMC8130202 DOI: 10.1093/ijnp/pyaa093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/12/2020] [Accepted: 12/03/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Neurogenesis in the neonatal period involves the proliferation and differentiation of neuronal stem/progenitor cells and the establishment of synaptic connections. This process plays a critical role in determining the normal development and maturation of the brain throughout life. Exposure to certain physical or chemical factors during the perinatal period can lead to many neuropathological defects that cause high cognitive dysfunction and are accompanied by abnormal hippocampal neurogenesis and plasticity. As an endocrine disruptor, gossypol is generally known to exert detrimental effects in animals exposed under experimental conditions. However, it is unclear whether gossypol affects neurogenesis in the hippocampal dentate gyrus during early developmental stages. METHODS Pregnant Institute of Cancer Research mice were treated with gossypol at a daily dose of 0, 20, and 50 mg/kg body weight from embryonic day 6.5 to postnatal day (P) 21. The changes of hippocampal neurogenesis as well as potential mechanisms were investigated by 5-bromo-2-deoxyuridine labeling, behavioral tests, immunofluorescence, quantitative reverse transcription-polymerase chain reaction, and western-blot analyses. RESULTS At P8, maternal gossypol exposure impaired neural stem cell proliferation in the dentate gyrus and decreased the number of newborn cells as a result of reduced proliferation of BLBP+ radial glial cells and Tbr2+ intermediate progenitor cells. At P21, the numbers of NeuN+ neurons and parvalbumin+ γ-aminobutyric acid-ergic interneurons were increased following 50 mg/kg gossypol exposure. In addition, gossypol induced hippocampal neuroinflammation, which may contribute to behavioral abnormalities and cognitive deficits and decrease synaptic plasticity. CONCLUSIONS Our findings suggest that developmental gossypol exposure affects hippocampal neurogenesis by targeting the proliferation and differentiation of neuronal stem/progenitor cells, cognitive functions, and neuroinflammation. The present data provide novel insights into the neurotoxic effects of gossypol on offspring.
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Affiliation(s)
- Xiaoyan Zhu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China,Correspondence: Xiaoyan Zhu, PhD, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China ()
| | - Yongji Wu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Jiarong Pan
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Cixia Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Jian Huang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Enhui Cui
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Ziluo Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Wentai Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Xuejun Chai
- College of Basic Medicine, Xi’An Medical University, Xi’An, PR China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, PR China
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Chai X, Zhang W, Li L, Wu Y, Zhu X, Zhao S. Profile of MIF in Developing Hippocampus: Association With Cell Proliferation and Neurite Outgrowth. Front Mol Neurosci 2020; 13:147. [PMID: 32903462 PMCID: PMC7434973 DOI: 10.3389/fnmol.2020.00147] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/15/2020] [Indexed: 11/13/2022] Open
Abstract
Proinflammatory cytokine macrophage migration inhibitory factor (MIF) is a multifunctional cytokine and has been found involved in many neurological diseases such as Alzheimer disease (AD), epilepsy, and multiple sclerosis. Previous studies have shown that MIF is expressed in neocortex, hippocampus, hypothalamus, cerebellum, and spinal cord in adult mice. It is expressed by astrocytes and activates microglias in neuroinflammation. Further studies have shown that MIF is detected in moss fibers of dentate granule cells and in apical dendrites of pyramidal neurons in adult hippocampus. Only NeuroD-positive immature granule neurons but not NeuN-positive mature neurons express MIF. These findings led us eager to know the exact role of MIF in the development of hippocampus. Therefore, we systematically checked the spatial and temporal expression pattern of MIF and characterized MIF-positive cells in hippocampus from mice aged from postnatal day 0 (P0) to 3 months. Our results showed that the lowest level of MIF protein occurred at P7 and mif mRNA increased from P0, reached a peak at P7, and stably expressed until P30 before declining dramatically at 3 months. MIF was localized in fibers of GFAP- and BLBP-positive radial glial precursor cells in dentate gyrus (DG). DCX-expressing newly generated neurons were MIF-negative. Inhibition of MIF by MIF antagonist S, R-3-(4-hydroxyphenyl)-4, 5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) reduced BrdU-positive cells. Interestingly, MIF was expressed by NeuN-positive GABAergic interneurons including parvalbumin-and Reelin-expressing cells in the DG. Neither NeuN-positive granule cells nor NeuN-positive pyramidal neurons expressed MIF. In transgenic mice, POMC-EGFP–positive immature dentate granule cells and Thy1-EGFP–positive mature granule cells were MIF-negative. Treatment of neuronal cultures with ISO-1 inhibited neurite outgrowth. Therefore, we conclude that MIF might be important for feature maintenance of neural stem cells and neurite outgrowth during hippocampal development.
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Affiliation(s)
- Xuejun Chai
- College of Basic Medicine, Xi'an Medical University, Xi'an, China
| | - Wei Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Lingling Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Yongji Wu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Xiaoyan Zhu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
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10
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Jossin Y. Reelin Functions, Mechanisms of Action and Signaling Pathways During Brain Development and Maturation. Biomolecules 2020; 10:biom10060964. [PMID: 32604886 PMCID: PMC7355739 DOI: 10.3390/biom10060964] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/24/2020] [Accepted: 06/24/2020] [Indexed: 12/14/2022] Open
Abstract
During embryonic development and adulthood, Reelin exerts several important functions in the brain including the regulation of neuronal migration, dendritic growth and branching, dendritic spine formation, synaptogenesis and synaptic plasticity. As a consequence, the Reelin signaling pathway has been associated with several human brain disorders such as lissencephaly, autism, schizophrenia, bipolar disorder, depression, mental retardation, Alzheimer’s disease and epilepsy. Several elements of the signaling pathway are known. Core components, such as the Reelin receptors very low-density lipoprotein receptor (VLDLR) and Apolipoprotein E receptor 2 (ApoER2), Src family kinases Src and Fyn, and the intracellular adaptor Disabled-1 (Dab1), are common to most but not all Reelin functions. Other downstream effectors are, on the other hand, more specific to defined tasks. Reelin is a large extracellular protein, and some aspects of the signal are regulated by its processing into smaller fragments. Rather than being inhibitory, the processing at two major sites seems to be fulfilling important physiological functions. In this review, I describe the various cellular events regulated by Reelin and attempt to explain the current knowledge on the mechanisms of action. After discussing the shared and distinct elements of the Reelin signaling pathway involved in neuronal migration, dendritic growth, spine development and synaptic plasticity, I briefly outline the data revealing the importance of Reelin in human brain disorders.
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Affiliation(s)
- Yves Jossin
- Laboratory of Mammalian Development & Cell Biology, Institute of Neuroscience, Université Catholique de Louvain, 1200 Brussels, Belgium
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11
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Jossin Y. Molecular mechanisms of cell polarity in a range of model systems and in migrating neurons. Mol Cell Neurosci 2020; 106:103503. [PMID: 32485296 DOI: 10.1016/j.mcn.2020.103503] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 05/23/2020] [Indexed: 01/09/2023] Open
Abstract
Cell polarity is defined as the asymmetric distribution of cellular components along an axis. Most cells, from the simplest single-cell organisms to highly specialized mammalian cells, are polarized and use similar mechanisms to generate and maintain polarity. Cell polarity is important for cells to migrate, form tissues, and coordinate activities. During development of the mammalian cerebral cortex, cell polarity is essential for neurogenesis and for the migration of newborn but as-yet undifferentiated neurons. These oriented migrations include both the radial migration of excitatory projection neurons and the tangential migration of inhibitory interneurons. In this review, I will first describe the development of the cerebral cortex, as revealed at the cellular level. I will then define the core molecular mechanisms - the Par/Crb/Scrib polarity complexes, small GTPases, the actin and microtubule cytoskeletons, and phosphoinositides/PI3K signaling - that are required for asymmetric cell division, apico-basal and front-rear polarity in model systems, including C elegans zygote, Drosophila embryos and cultured mammalian cells. As I go through each core mechanism I will explain what is known about its importance in radial and tangential migration in the developing mammalian cerebral cortex.
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Affiliation(s)
- Yves Jossin
- Laboratory of Mammalian Development & Cell Biology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium.
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12
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Zhu X, Wu Y, Li C, Yan W, Pan J, Wang S, Zhao S. Prenatal Exposure to Gossypol Impairs Corticogenesis of Mouse. Front Neurosci 2020; 14:318. [PMID: 32317927 PMCID: PMC7146080 DOI: 10.3389/fnins.2020.00318] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 03/18/2020] [Indexed: 12/16/2022] Open
Abstract
Gossypol is a yellow polyphenolic compounds extracted from roots, stems and seeds of cotton plants. Excessive intake of gossypol induces severe pathological signs of toxicity in livestock and wildlife. Currently, gossypol has received widespread attention for its toxic effects on the reproductive system. However, reports of the effects of gossypol during corticogenesis and the development of the mouse cerebral cortex are unavailable. In the present study, gossypol was orally administrated at a dose of 0, 20, and 50 mg/kg body weight/day to pregnant mice from embryonic day 6.5 to the time of sample collection. We used in utero electroporation and immunofluorescence to demonstrate that gossypol impaired cortical neuronal migration. Furthermore, labeling with 5-bromo-2-deoxyuridine and western blot analysis revealed that gossypol disturbed the balance between proliferation and differentiation of neural progenitors, inhibited neural progenitor cell proliferation, neuronal differentiation, and maturation. Additionally, cortical progenitor apoptotic cell death increased in the developing gossypol-treated cortex, which was associated with NF-κB and MAPK pathways. In conclusion, our findings indicate that gossypol exposure disrupted neurogenesis in the developing neocortex, suggesting the potentially harmful impact of gossypol on the cerebral cortex development of humans and livestock.
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Affiliation(s)
- Xiaoyan Zhu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Yongji Wu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Cixia Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Wenyong Yan
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Jiarong Pan
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Shuzhong Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
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13
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Mavrovic M, Uvarov P, Delpire E, Vutskits L, Kaila K, Puskarjov M. Loss of non-canonical KCC2 functions promotes developmental apoptosis of cortical projection neurons. EMBO Rep 2020; 21:e48880. [PMID: 32064760 DOI: 10.15252/embr.201948880] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 01/16/2020] [Accepted: 01/24/2020] [Indexed: 01/01/2023] Open
Abstract
KCC2, encoded in humans by the SLC12A5 gene, is a multifunctional neuron-specific protein initially identified as the chloride (Cl- ) extruder critical for hyperpolarizing GABAA receptor currents. Independently of its canonical function as a K-Cl cotransporter, KCC2 regulates the actin cytoskeleton via molecular interactions mediated through its large intracellular C-terminal domain (CTD). Contrary to the common assumption that embryonic neocortical projection neurons express KCC2 at non-significant levels, here we show that loss of KCC2 enhances apoptosis of late-born upper-layer cortical projection neurons in the embryonic brain. In utero electroporation of plasmids encoding truncated, transport-dead KCC2 constructs retaining the CTD was as efficient as of that encoding full-length KCC2 in preventing elimination of migrating projection neurons upon conditional deletion of KCC2. This was in contrast to the effect of a full-length KCC2 construct bearing a CTD missense mutation (KCC2R952H ), which disrupts cytoskeletal interactions and has been found in patients with neurological and psychiatric disorders, notably seizures and epilepsy. Together, our findings indicate ion transport-independent, CTD-mediated regulation of developmental apoptosis by KCC2 in migrating cortical projection neurons.
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Affiliation(s)
- Martina Mavrovic
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Pavel Uvarov
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University, Nashville, TN, USA
| | - Laszlo Vutskits
- Department of Basic Neurosciences, University of Geneva Medical School, Geneva 4, Switzerland.,Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva, Geneva 4, Switzerland
| | - Kai Kaila
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Martin Puskarjov
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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14
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Meka DP, Scharrenberg R, Zhao B, Kobler O, König T, Schaefer I, Schwanke B, Klykov S, Richter M, Eggert D, Windhorst S, Dotti CG, Kreutz MR, Mikhaylova M, Calderon de Anda F. Radial somatic F-actin organization affects growth cone dynamics during early neuronal development. EMBO Rep 2019; 20:e47743. [PMID: 31650708 PMCID: PMC6893363 DOI: 10.15252/embr.201947743] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 09/06/2019] [Accepted: 09/27/2019] [Indexed: 11/16/2022] Open
Abstract
The centrosome is thought to be the major neuronal microtubule‐organizing center (MTOC) in early neuronal development, producing microtubules with a radial organization. In addition, albeit in vitro, recent work showed that isolated centrosomes could serve as an actin‐organizing center, raising the possibility that neuronal development may, in addition, require a centrosome‐based actin radial organization. Here, we report, using super‐resolution microscopy and live‐cell imaging of cultured rodent neurons, F‐actin organization around the centrosome with dynamic F‐actin aster‐like structures with F‐actin fibers extending and retracting actively. Photoactivation/photoconversion experiments and molecular manipulations of F‐actin stability reveal a robust flux of somatic F‐actin toward the cell periphery. Finally, we show that somatic F‐actin intermingles with centrosomal PCM‐1 (pericentriolar material 1 protein) satellites. Knockdown of PCM‐1 and disruption of centrosomal activity not only affect F‐actin dynamics near the centrosome but also in distal growth cones. Collectively, the data show a radial F‐actin organization during early neuronal development, which might be a cellular mechanism for providing peripheral regions with a fast and continuous source of actin polymers, hence sustaining initial neuronal development.
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Affiliation(s)
- Durga Praveen Meka
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Robin Scharrenberg
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bing Zhao
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver Kobler
- Combinatorial Neuroimaging Core Facility (CNI), Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Theresa König
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Irina Schaefer
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Birgit Schwanke
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sergei Klykov
- Emmy-Noether Group "Neuronal Protein Transport", Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Melanie Richter
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dennis Eggert
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.,Heinrich Pette Institute-Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sabine Windhorst
- Department of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Carlos G Dotti
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, Madrid, Spain
| | - Michael R Kreutz
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Leibniz Guest Group "Dendritic Organelles and Synaptic Function", Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marina Mikhaylova
- Emmy-Noether Group "Neuronal Protein Transport", Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Froylan Calderon de Anda
- RG Neuronal Development, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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15
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Dlugosz P, Tresky R, Nimpf J. Differential Action of Reelin on Oligomerization of ApoER2 and VLDL Receptor in HEK293 Cells Assessed by Time-Resolved Anisotropy and Fluorescence Lifetime Imaging Microscopy. Front Mol Neurosci 2019; 12:53. [PMID: 30873003 PMCID: PMC6403468 DOI: 10.3389/fnmol.2019.00053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/12/2019] [Indexed: 01/12/2023] Open
Abstract
The canonical Reelin signaling cascade regulates correct neuronal layering during embryonic brain development. Details of this pathway are still not fully understood since the participating components are highly variable and create a complex mixture of interacting molecules. Reelin is proteolytically processed resulting in five different fragments some of which carrying the binding site for two different but highly homologous receptors, apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (VLDLR). The receptors are expressed in different variants in different areas of the developing brain. Binding of Reelin and its central fragment to the receptors results in phosphorylation of the intracellular adapter disabled-1 (Dab1) in neurons. Here, we studied the changes of the arrangement of the receptors upon Reelin binding and its central fragment at the molecular level in human embryonic kidney 293 (HEK293) cells by time-resolved anisotropy and fluorescence lifetime imaging microscopy (FLIM). In the off-state of the pathway ApoER2 and VLDLR form homo or hetero-di/oligomers. Upon binding of full length Reelin ApoER2 and VLDLR homo-oligomers are rearranged to higher order receptor clusters which leads to Dab1 phosphorylation. When the central fragment of Reelin binds to the receptors the cluster size of homo-oligomers is not affected and Dab1 is not phosphorylated. Hetero-oligomerization, however, can be induced, but does not lead to Dab1 phosphorylation. Cells expressing only ApoER2 or VLDLR change their shape when stimulated with the central fragment. Cells expressing ApoER2 produce filopodia/lamellipodia and cell size increases, whereas VLDLR-expressing cells decrease in size. These findings demonstrate that the primary event in the canonical Reelin pathway is the rearrangement of preformed receptor homo-oligomers to higher order clusters. In addition the possibility of yet another signaling mechanism which is mediated by the central Reelin fragment independent of Dab1 phosphorylation became apparent.
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Affiliation(s)
- Paula Dlugosz
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
| | - Roland Tresky
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
| | - Johannes Nimpf
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University Vienna, Vienna, Austria
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16
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Vaswani AR, Weykopf B, Hagemann C, Fried HU, Brüstle O, Blaess S. Correct setup of the substantia nigra requires Reelin-mediated fast, laterally-directed migration of dopaminergic neurons. eLife 2019; 8:41623. [PMID: 30689541 PMCID: PMC6349407 DOI: 10.7554/elife.41623] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/14/2019] [Indexed: 12/21/2022] Open
Abstract
Midbrain dopaminergic (mDA) neurons migrate to form the laterally-located substantia nigra pars compacta (SN) and medially-located ventral tegmental area (VTA), but little is known about the underlying cellular and molecular processes. Here we visualize the dynamic cell morphologies of tangentially migrating SN-mDA neurons in 3D and identify two distinct migration modes. Slow migration is the default mode in SN-mDA neurons, while fast, laterally-directed migration occurs infrequently and is strongly associated with bipolar cell morphology. Tangential migration of SN-mDA neurons is altered in absence of Reelin signaling, but it is unclear whether Reelin acts directly on migrating SN-mDA neurons and how it affects their cell morphology and migratory behavior. By specifically inactivating Reelin signaling in mDA neurons we demonstrate its direct role in SN-mDA tangential migration. Reelin promotes laterally-biased movements in mDA neurons during their slow migration mode, stabilizes leading process morphology and increases the probability of fast, laterally-directed migration.
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Affiliation(s)
- Ankita Ravi Vaswani
- Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Beatrice Weykopf
- Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Cathleen Hagemann
- Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Hans-Ulrich Fried
- Light Microscope Facility, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Sandra Blaess
- Neurodevelopmental Genetics, Institute of Reconstructive Neurobiology, University of Bonn School of Medicine & University Hospital Bonn, Bonn, Germany
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17
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Wang D, Enck J, Howell BW, Olson EC. Ethanol Exposure Transiently Elevates but Persistently Inhibits Tyrosine Kinase Activity and Impairs the Growth of the Nascent Apical Dendrite. Mol Neurobiol 2019; 56:5749-5762. [PMID: 30674037 DOI: 10.1007/s12035-019-1473-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022]
Abstract
Dendritogenesis can be impaired by exposure to alcohol, and aspects of this impairment share phenotypic similarities to dendritic defects observed after blockade of the Reelin-Dab1 tyrosine kinase signaling pathway. In this study, we find that 10 min of alcohol exposure (400 mg/dL ethanol) by itself causes an unexpected increase in tyrosine phosphorylation of many proteins including Src and Dab1 that are essential downstream effectors of Reelin signaling. This increase in phosphotyrosine is dose-dependent and blockable by selective inhibitors of Src Family Kinases (SFKs). However, the response is transient, and phosphotyrosine levels return to baseline after 30 min of continuous ethanol exposure, both in vitro and in vivo. During this latter period, Src is inactivated and Reelin application cannot stimulate Dab1 phosphorylation. This suggests that ethanol initially activates but then silences the Reelin-Dab1 signaling pathway by brief activation and then sustained inactivation of SFKs. Time-lapse analyses of dendritic growth dynamics show an overall decrease in growth and branching compared to controls after ethanol-exposure that is similar to that observed with Reelin-deficiency. However, unlike Reelin-signaling disruptions, the dendritic filopodial speeds are decreased after ethanol exposure, and this decrease is associated with sustained dephosphorylation and activation of cofilin, an F-actin severing protein. These findings suggest that persistent Src inactivation coupled to cofilin activation may contribute to the dendritic disruptions observed with fetal alcohol exposure.
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Affiliation(s)
- Dandan Wang
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Ave, Syracuse, NY, 13210, USA.,Developmental Exposure to Alcohol Research Center (DEARC), Binghamton University, Binghamton, NY, 13902, USA
| | - Joshua Enck
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Ave, Syracuse, NY, 13210, USA.,Developmental Exposure to Alcohol Research Center (DEARC), Binghamton University, Binghamton, NY, 13902, USA
| | - Brian W Howell
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Ave, Syracuse, NY, 13210, USA
| | - Eric C Olson
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Ave, Syracuse, NY, 13210, USA. .,Developmental Exposure to Alcohol Research Center (DEARC), Binghamton University, Binghamton, NY, 13902, USA.
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18
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Abstract
Neuronal connectivity in the cortex is determined by the laminar positioning of neurons. An important determinant of laminar positioning is likely to be the control of leading process behavior during migration, maintaining their tips directed toward the pia. In this study, we provide evidence that pial bone morphogenetic protein (Bmp) signaling regulates cortical neuronal migration during cortical layer formation. Specific disruption of pial Bmp ligands impaired the positioning of early-born neurons in the deep layer; further, cell-autonomous inhibition of Smad4, a core nuclear factor mediating Bmp signaling, in the cortical radial glial cells or postmitotic cortical neurons also produced neuronal migration defects that blurred the cortical layers. We found that leading processes were abnormal and that this was accompanied by excess dephosphorylated cofilin-1, an actin-severing protein, in Smad4 mutant neurons. This suggested that regulation of cofilin-1 might transduce Bmp signaling in the migrating neurons. Ectopic expression of a phosphorylation-defective form of cofilin-1 in the late-born wild-type neurons led them to stall in the deep layer, similar to the Smad4 mutant neurons. Expression of a phosphomimetic variant of cofilin-1 in the Smad4 mutant neurons rescued the migration defects. This suggests that cofilin-1 activity underlies Bmp-mediated cortical neuronal migration. This study shows that cofilin-1 mediates pial Bmp signaling during the positioning of cortical neurons and the formation of cortical layers.
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Affiliation(s)
- Youngshik Choe
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.,Korea Brain Research Institute, Dong-gu, Daegu, Korea
| | - Samuel J Pleasure
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.,Department of Neuroscience, University of California, San Francisco, San Francisco, CA, USA.,Department of Developmental Stem Cell Biology, University of California, San Francisco, San Francisco, CA, USA.,Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and University of California, San Francisco, San Francisco, CA, USA
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19
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Nicole O, Bell DM, Leste-Lasserre T, Doat H, Guillemot F, Pacary E. A novel role for CAMKIIβ in the regulation of cortical neuron migration: implications for neurodevelopmental disorders. Mol Psychiatry 2018; 23:2209-2226. [PMID: 29712998 PMCID: PMC6129389 DOI: 10.1038/s41380-018-0046-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/11/2018] [Accepted: 02/28/2018] [Indexed: 12/19/2022]
Abstract
Perturbation of CaMKIIβ expression has been associated with multiple neuropsychiatric diseases, highlighting CaMKIIβ as a gene of interest. Yet, in contrast to CaMKIIα, the specific functions of CaMKIIβ in the brain remain poorly explored. Here, we reveal a novel function for this CaMKII isoform in vivo during neuronal development. By using in utero electroporation, we show that CaMKIIβ is an important regulator of radial migration of projection neurons during cerebral cortex development. Knockdown of CaMKIIβ causes accelerated migration of nascent pyramidal neurons, whereas overexpression of CaMKIIβ inhibits migration, demonstrating that precise regulation of CaMKIIβ expression is required for correct neuronal migration. More precisely, CaMKIIβ controls the multipolar-bipolar transition in the intermediate zone and locomotion in the cortical plate through its actin-binding and -bundling activities. In addition, our data indicate that a fine-tuned balance between CaMKIIβ and cofilin activities is necessary to ensure proper migration of cortical neurons. Thus, our findings define a novel isoform-specific function for CaMKIIβ, demonstrating that CaMKIIβ has a major biological function in the developing brain.
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Affiliation(s)
- Olivier Nicole
- CNRS, UMR5293, Institut des Maladies Neurodégénératives, F-33000 Bordeaux, France,Université de Bordeaux, F-33000 Bordeaux, France
| | - Donald M. Bell
- Confocal and Image Analysis Facility, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Hélène Doat
- Transcriptome Facility, INSERM U1215, Neurocentre Magendie, F-33000 Bordeaux, France
| | | | - Emilie Pacary
- Université de Bordeaux, F-33000, Bordeaux, France. .,INSERM U1215, Neurocentre Magendie, F-33000, Bordeaux, France.
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20
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Prume M, Rollenhagen A, Lübke JHR. Structural and Synaptic Organization of the Adult Reeler Mouse Somatosensory Neocortex: A Comparative Fine-Scale Electron Microscopic Study of Reeler With Wild Type Mice. Front Neuroanat 2018; 12:80. [PMID: 30344480 PMCID: PMC6182073 DOI: 10.3389/fnana.2018.00080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/13/2018] [Indexed: 11/17/2022] Open
Abstract
The reeler mouse has been widely used to study various aspects of cortico- and synaptogenesis, but also as a model for several neurological and neurodegenerative disorders. In contrast to development, comparably little is known about the neuronal composition and synaptic organization of the adult reeler mouse neocortex, in particular at the fine-scale electron microscopic level, which was investigated here and compared with wild type (WT) mice. In this study, the “barrel field” of the adult reeler and WT mouse somatosensory neocortex is used as a model system. In reeler the characteristic six-layered structure is no longer existent, but replaced by a conglomerate of neurons organized in homologous clusters with maintained morphological identity and heterologous clusters between neurons and/or oligodendrocytes. These clusters are loosely scattered throughout the neocortical mass between the pial surface and the white matter. In contrast to WT, layer 1 (L1), if existent, seems to be diluted into the volume of the neocortical mass with no clear boundary. L1 also contains clusters of migrated or persistent neurons, oligodendro- and astrocytes. As in WT, myelinated and unmyelinated axons were found throughout the neocortical mass, but in reeler they were organized in massive fiber bundles with a high fiber packing density. A prominent and massive thalamocortical projection traverses through the neocortical mass, always accompanied by numerous “active” oligodendrocytes whereas in WT no such projections were found and “silent” oligodendrocytes were restricted to the white matter. In the adult reeler mouse neocortex, synaptic boutons terminate on somata, dendritic shafts, spines of different types and axon initial segments with no signs of structural distortion and/or degeneration, indicating a “normal” postsynaptic innervation pattern of neurons. In addition, synaptic complexes between boutons and their postsynaptic targets are tightly ensheathed by fine astrocytic processes, as in WT. In conclusion, the neuronal clusters may represent a possible alternative organization principle in adult reeler mice “replacing” layer formation. If so, these homologous clusters may represent individual “functional units” where neurons are highly interconnected and may function as the equivalent of neurons integrated in a cortical layer. The structural composition and postsynaptic innervation pattern of neurons by synaptic boutons provide the structural basis for the establishment of a functional although altered cortical network in the adult reeler mouse.
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Affiliation(s)
- Miriam Prume
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany
| | - Joachim H R Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH University Hospital Aachen, Aachen, Germany.,JARA Translational Brain Medicine, Jülich, Germany
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21
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Further studies about Coactosin-like protein-1 affecting the migration of mouse neocortical neurons. J Mol Histol 2018; 49:519-530. [PMID: 30128637 DOI: 10.1007/s10735-018-9790-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 07/27/2018] [Indexed: 12/18/2022]
Abstract
During the development of mammalian cortex, late neurons generated by neuronal progenitors bypass earlier-born neurons and migrate to reach upper layers of cortical plate in an inner-to-outer fashion. Filamentous-actin (F-actin) can regulate neuronal migration, whereas Coactosin-like protein 1 (Cotl1) modulates F-actin. Lys 75 and Arg 73 of Cotl1 play an important role in binding F-actin; when they are mutated to Glu, Cotl1 cannot bind F-actin, called as a non-actin-binding mutant (ABM). The Lys 131 site of Cotl1, the 5-Lipoxygenase (5LO) binding site, is spatially close to Lys 75, leading to impact the binding of Cotl1 to F-actin. When Lys 131 is mutated to Ala (K131A), Cotl1 cannot bind to 5LO. We have demonstrated that overexpression of Cotl1 inhibited neuronal migration and increased the length of neuronal leading processes. To further explore cellular and molecular mechanisms of Cotl1's effect on neuronal migration, we constructed two mutant vectors-Cotl1-ABM and Cotl1-K131A and studied using in utero electroporation and primary neuronal culture technique. Results indicated that in the Cotl1-ABM group, the neuronal migration and length of the leading process both recovered as control neurons at the postnatal day 1 (P1), while in the Cotl1-K131A group, numerous neurons remained in deeper layers of cortical plate or intermediate zone. However, at P7, most Cotl1-K131A transfected neurons reached their destination. Moreover, we found that overexpression of Cotl1 inhibited the proliferation and mitotic activity of NPs. Therefore, These results demonstrated that Cotl1 played an important role in mouse neocortical development.
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22
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Ducharme P, Zarruk JG, David S, Paquin J. The ferroxidase ceruloplasmin influences Reelin processing, cofilin phosphorylation and neuronal organization in the developing brain. Mol Cell Neurosci 2018; 92:104-113. [PMID: 30077770 DOI: 10.1016/j.mcn.2018.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/10/2018] [Accepted: 07/30/2018] [Indexed: 12/09/2022] Open
Abstract
Ceruloplasmin (Cp) is an important extracellular regulator of iron metabolism. We showed previously that it stimulates Reelin proteolytic processing and cell aggregation in cultures of developing neurons. Reelin is a secreted protein required for the correct positioning of neurons in the brain. It is cleaved in vivo into N-terminally-derived 300K and 180K fragments through incompletely known mechanisms. One of Reelin signaling targets is the actin-binding protein cofilin, the phosphorylation of which is diminished in Reelin-deficient mice. This work looked for in vivo evidence of a relationship between Cp, Reelin and neuronal organization during brain development by analyzing wild-type and Cp-null mice. Cp as well as the full-length, 300K and 180K Reelin species appeared together in wild-type brains at embryonic day (E) 12.5 by immunoblotting. In wild-type compared to Cp-null brains, there was more 300K Reelin from E12.5 to E17.5, a period characterized by extensive, radially directed neuronal migration in the cerebral cortex. Immunofluorescence labeling of tissue sections at E16.5 revealed the localization of Cp with radial glia and meningeal cells adjacent to Reelin-producing Cajal-Retzius neurons, underlining the proximity of Cp and Reelin. Cofilin phosphorylation was seen starting at E10.5-E12.5 and lasted longer until postnatal day 7 in wild-type than Cp-null mice. Finally, using CUX1 as a marker revealed defective accumulation of neurons in layers II/III in neonatal and adult Cp-null mice. These results combined with our earlier work point to a potentially new role of Cp in Reelin processing and signaling and neuronal organization in the cerebral cortex in vivo.
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Affiliation(s)
- Philippe Ducharme
- Département de Chimie and Centre BioMed, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montreal, Quebec H3C 3P8, Canada.
| | - Juan G Zarruk
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, 1650 Cedar Ave., Montreal, Quebec H3G 1A4, Canada.
| | - Samuel David
- Centre for Research in Neuroscience, The Research Institute of the McGill University Health Center, 1650 Cedar Ave., Montreal, Quebec H3G 1A4, Canada.
| | - Joanne Paquin
- Département de Chimie and Centre BioMed, Université du Québec à Montréal, C.P. 8888, Succ. Centre-ville, Montreal, Quebec H3C 3P8, Canada.
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23
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Li G, Yin Y, Chen J, Fan Y, Ma J, Huang Y, Chen C, Dai P, Chen S, Zhao S. Coactosin-like protein 1 inhibits neuronal migration during mouse corticogenesis. J Vet Sci 2018; 19:21-26. [PMID: 28385010 PMCID: PMC5799395 DOI: 10.4142/jvs.2018.19.1.21] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 12/19/2016] [Accepted: 02/07/2017] [Indexed: 11/20/2022] Open
Abstract
Coactosin-like protein 1 (Cotl1), a member of the actin-depolymerizing factor (ADF)/cofilin family, was first purified from a soluble fraction of Dictyostelium discoideum cells. Neuronal migration requires cytoskeletal remodeling and actin regulation. Although Cotl1 strongly binds to F-actin, the role of Cotl1 in neuronal migration remains undescribed. In this study, we revealed that Cotl1 overexpression impaired migrationof both early- and late-born neurons during mouse corticogenesis. Moreover, Cotl1 overexpression delayed, rather than blocked, neuronal migration in late-born neurons. Cotl1 expression disturbed the morphology of migrating neurons, lengthening the leading processes. This study is the first to investigate the function of Cotl1, and the results indicate that Cotl1 is involved in the regulation of neuronal migration and morphogenesis.
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Affiliation(s)
- Guohong Li
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Yupeng Yin
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Jiong Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Yanle Fan
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Juhong Ma
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Yingxue Huang
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Chen Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Pengxiu Dai
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Shulin Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
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Schlau M, Terheyden-Keighley D, Theis V, Mannherz HG, Theiss C. VEGF Triggers the Activation of Cofilin and the Arp2/3 Complex within the Growth Cone. Int J Mol Sci 2018; 19:ijms19020384. [PMID: 29382077 PMCID: PMC5855606 DOI: 10.3390/ijms19020384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/16/2018] [Accepted: 01/24/2018] [Indexed: 01/05/2023] Open
Abstract
A crucial neuronal structure for the development and regeneration of neuronal networks is the axonal growth cone. Affected by different guidance cues, it grows in a predetermined direction to reach its final destination. One of those cues is the vascular endothelial growth factor (VEGF), which was identified as a positive effector for growth cone movement. These positive effects are mainly mediated by a reorganization of the actin network. This study shows that VEGF triggers a tight colocalization of cofilin and the Arp2/3 complex to the actin cytoskeleton within chicken dorsal root ganglia (DRG). Live cell imaging after microinjection of GFP (green fluorescent protein)-cofilin and RFP (red fluorescent protein)-LifeAct revealed that both labeled proteins rapidly redistributed within growth cones, and showed a congruent distribution pattern after VEGF supplementation. Disruption of signaling upstream of cofilin via blocking LIM-kinase (LIMK) activity resulted in growth cones displaying regressive growth behavior. Microinjection of GFP-p16b (a subunit of the Arp2/3 complex) and RFP-LifeAct revealed that both proteins redistributed into lamellipodia of the growth cone within minutes after VEGF stimulation. Disruption of the signaling to the Arp2/3 complex in the presence of VEGF by inhibition of N-WASP (neuronal Wiskott–Aldrich–Scott protein) caused retraction of growth cones. Hence, cofilin and the Arp2/3 complex appear to be downstream effector proteins of VEGF signaling to the actin cytoskeleton of DRG growth cones. Our data suggest that VEGF simultaneously affects different pathways for signaling to the actin cytoskeleton, since activation of cofilin occurs via inhibition of LIMK, whereas activation of Arp2/3 is achieved by stimulation of N-WASP.
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Affiliation(s)
- Matthias Schlau
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
| | - Daniel Terheyden-Keighley
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
| | - Verena Theis
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
| | - Hans Georg Mannherz
- Research Group Molecular Cardiology, University Hospital Bergmannsheil and St. Josef Hospital, c/o Clinical Pharmacology, Ruhr-University, 44780 Bochum, Germany.
| | - Carsten Theiss
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
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25
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Trajectory Analysis Unveils Reelin's Role in the Directed Migration of Granule Cells in the Dentate Gyrus. J Neurosci 2017; 38:137-148. [PMID: 29138282 DOI: 10.1523/jneurosci.0988-17.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 11/01/2017] [Accepted: 11/03/2017] [Indexed: 11/21/2022] Open
Abstract
Reelin controls neuronal migration and layer formation. Previous studies in reeler mice deficient in Reelin focused on the result of the developmental process in fixed tissue sections. It has remained unclear whether Reelin affects the migratory process, migration directionality, or migrating neurons guided by the radial glial scaffold. Moreover, Reelin has been regarded as an attractive signal because newly generated neurons migrate toward the Reelin-containing marginal zone. Conversely, Reelin might be a stop signal because migrating neurons in reeler, but not in wild-type mice, invade the marginal zone. Here, we monitored the migration of newly generated proopiomelanocortin-EGFP-expressing dentate granule cells in slice cultures from reeler, reeler-like mutants and wild-type mice of either sex using real-time microscopy. We discovered that not the actual migratory process and migratory speed, but migration directionality of the granule cells is controlled by Reelin. While wild-type granule cells migrated toward the marginal zone of the dentate gyrus, neurons in cultures from reeler and reeler-like mutants migrated randomly in all directions as revealed by vector analyses of migratory trajectories. Moreover, live imaging of granule cells in reeler slices cocultured to wild-type dentate gyrus showed that the reeler neurons changed their directions and migrated toward the Reelin-containing marginal zone of the wild-type culture, thus forming a compact granule cell layer. In contrast, directed migration was not observed when Reelin was ubiquitously present in the medium of reeler slices. These results indicate that topographically administered Reelin controls the formation of a granule cell layer.SIGNIFICANCE STATEMENT Neuronal migration and the various factors controlling its onset, speed, directionality, and arrest are poorly understood. Slice cultures offer a unique model to study the migration of individual neurons in an almost natural environment. In the present study, we took advantage of the expression of proopiomelanocortin-EGFP by newly generated, migrating granule cells to analyze their migratory trajectories in hippocampal slice cultures from wild-type mice and mutants deficient in Reelin signaling. We show that the compartmentalized presence of Reelin is essential for the directionality, but not the actual migratory process or speed, of migrating granule cells leading to their characteristic lamination in the dentate gyrus.
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26
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Frotscher M, Zhao S, Wang S, Chai X. Reelin Signaling Inactivates Cofilin to Stabilize the Cytoskeleton of Migrating Cortical Neurons. Front Cell Neurosci 2017; 11:148. [PMID: 28588454 PMCID: PMC5440592 DOI: 10.3389/fncel.2017.00148] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/05/2017] [Indexed: 12/31/2022] Open
Abstract
Neurons are highly polarized cells. They give rise to several dendrites but only one axon. In addition, many neurons show a preferred orientation. For example, pyramidal neurons of the cerebral cortex extend their apical dendrites toward the cortical surface while their axons run in opposite direction toward the white matter. This characteristic orientation reflects the migratory trajectory of a pyramidal cell during cortical development: the leading process (the future apical dendrite) extends toward the marginal zone (MZ) and the trailing process (the future axon) toward the intermediate zone (IZ) while the cells migrate radially to reach their destination in the cortical plate (CP). In this review article, we summarize the function of Reelin, an extracellular matrix protein synthesized by Cajal-Retzius cells in the MZ, in the development of the characteristic orientation of the leading processes running perpendicular to the cortical surface. Reelin promotes migration toward the cortical surface since late-generated cortical neurons in the reeler mutant are unable to reach upper cortical layers. Likewise, Reelin is important for the orientation and maintenance of the leading processes of migrating neurons since they are misoriented in the developing reeler cortex, as are the apical dendrites of pyramidal cells in the mature mutant. Reelin-induced phosphorylation of cofilin, an actin-associated protein, is crucial since pyramidal neurons transfected by in utero electroporation (IUE) with a non-phosphorylatable form of cofilin (cofilinS3A) show severe migration defects reminiscent of those in the reeler mutant. Remarkably, migration of neurons in the cortex of reeler mice was partially rescued by transfecting them with LIM kinase 1 (LIMK1), the kinase that induces phosphorylation of cofilin at serine3, or with a pseudo-phosphorylated cofilin mutant (cofilinS3E). Together these results indicate that Reelin-induced phosphorylation of cofilin is an important component in the orientation and directed migration of cortical neurons and in their correct lamination.
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Affiliation(s)
- Michael Frotscher
- Center for Molecular Neurobiology Hamburg (ZMNH), Institute for Structural Neurobiology, University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F UniversityYangling, China
| | - Shaobo Wang
- Center for Molecular Neurobiology Hamburg (ZMNH), Institute for Structural Neurobiology, University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Xuejun Chai
- Center for Molecular Neurobiology Hamburg (ZMNH), Institute for Structural Neurobiology, University Medical Center Hamburg-EppendorfHamburg, Germany
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27
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Konietzny A, Bär J, Mikhaylova M. Dendritic Actin Cytoskeleton: Structure, Functions, and Regulations. Front Cell Neurosci 2017; 11:147. [PMID: 28572759 PMCID: PMC5435805 DOI: 10.3389/fncel.2017.00147] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/05/2017] [Indexed: 12/28/2022] Open
Abstract
Actin is a versatile and ubiquitous cytoskeletal protein that plays a major role in both the establishment and the maintenance of neuronal polarity. For a long time, the most prominent roles that were attributed to actin in neurons were the movement of growth cones, polarized cargo sorting at the axon initial segment, and the dynamic plasticity of dendritic spines, since those compartments contain large accumulations of actin filaments (F-actin) that can be readily visualized using electron- and fluorescence microscopy. With the development of super-resolution microscopy in the past few years, previously unknown structures of the actin cytoskeleton have been uncovered: a periodic lattice consisting of actin and spectrin seems to pervade not only the whole axon, but also dendrites and even the necks of dendritic spines. Apart from that striking feature, patches of F-actin and deep actin filament bundles have been described along the lengths of neurites. So far, research has been focused on the specific roles of actin in the axon, while it is becoming more and more apparent that in the dendrite, actin is not only confined to dendritic spines, but serves many additional and important functions. In this review, we focus on recent developments regarding the role of actin in dendrite morphology, the regulation of actin dynamics by internal and external factors, and the role of F-actin in dendritic protein trafficking.
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Affiliation(s)
- Anja Konietzny
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Julia Bär
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Marina Mikhaylova
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
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28
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Hirota Y, Nakajima K. Control of Neuronal Migration and Aggregation by Reelin Signaling in the Developing Cerebral Cortex. Front Cell Dev Biol 2017; 5:40. [PMID: 28507985 PMCID: PMC5410752 DOI: 10.3389/fcell.2017.00040] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/31/2017] [Indexed: 11/13/2022] Open
Abstract
The mammalian cerebral neocortex has a well-organized laminar structure, achieved by the highly coordinated control of neuronal migration. During cortical development, excitatory neurons born near the lateral ventricle migrate radially to reach their final positions to form the cortical plate. During this process, dynamic changes are observed in the morphologies and migration modes, including multipolar migration, locomotion, and terminal translocation, of the newborn neurons. Disruption of these migration processes can result in neuronal disorders such as lissencephaly and periventricular heterotopia. The extracellular protein, Reelin, mainly secreted by the Cajal-Retzius neurons in the marginal zone during development, plays a crucial role in the neuronal migration and neocortical lamination. Reelin signaling, which exerts essential roles in the formation of the layered neocortex, is triggered by the binding of Reelin to its receptors, ApoER2 and VLDLR, followed by phosphorylation of the Dab1 adaptor protein. Accumulating evidence suggests that Reelin signaling controls multiple steps of neuronal migration, including the transition from multipolar to bipolar neurons, terminal translocation, and termination of migration beneath the marginal zone. In addition, it has been shown that ectopically expressed Reelin can cause neuronal aggregation via an N-cadherin-mediated manner. This review attempts to summarize our knowledge of the roles played by Reelin in neuronal migration and the underlying mechanisms.
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Affiliation(s)
- Yuki Hirota
- Department of Anatomy, Keio University School of MedicineTokyo, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of MedicineTokyo, Japan
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29
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Xie J, Li X, Zhang W, Chai X, Huang Y, Li K, Cheng X, Zhao S. Aberrant expression of LIMK1 impairs neuronal migration during neocortex development. Histochem Cell Biol 2016; 147:471-479. [PMID: 27844143 DOI: 10.1007/s00418-016-1514-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2016] [Indexed: 12/25/2022]
Abstract
Neuronal migration is essential for the formation of cortical layers, and proper neuronal migration requires the coordination of cytoskeletal regulation. LIMK1 is a serine/threonine protein kinase that mediates actin dynamics by regulating actin depolymerization factor/cofilin. However, the role of LIMK1 in neuronal migration and its potential mechanism remains elusive. Here, we found that using the in utero electroporation to overexpress LIMK1 and its mutants, constitutively active LIMK1 (LIMK1-CA) and dominant-negative LIMK1 (LIMK1-DN), impaired neuronal migration in the embryonic mouse brain. In addition, the aberrant expression of LIMK1-WT and LIMK1-CA induced abnormal branching and increased the length of the leading process, while LIMK1-DN-transfected neurons gave rise to two leading processes. Furthermore, the co-transfection of LIMK1-CA and cofilin-S3A partially rescued the migration deficiency and fully rescued the morphological changes in migrating neurons induced by LIMK1-CA. Our results indicated that LIMK1 negatively regulated neuronal migration by affecting the neuronal cytoskeleton and that its effects were partly mediated by cofilin phosphorylation.
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Affiliation(s)
- Jiongfang Xie
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Xuzhao Li
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Wei Zhang
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Xuejun Chai
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Yingxue Huang
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Kaikai Li
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Xinran Cheng
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, No.22 Xinong Road, Yangling, 712100, Shaanxi, People's Republic of China.
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30
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Chai X, Frotscher M. How does Reelin signaling regulate the neuronal cytoskeleton during migration? NEUROGENESIS 2016; 3:e1242455. [PMID: 28265585 DOI: 10.1080/23262133.2016.1242455] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/15/2016] [Accepted: 09/25/2016] [Indexed: 01/17/2023]
Abstract
Neuronal migration is an essential step in the formation of laminated brain structures. In the developing cerebral cortex, pyramidal neurons migrate toward the Reelin-containing marginal zone. Reelin is an extracellular matrix protein synthesized by Cajal-Retzius cells. In this review, we summarize our recent results and hypotheses on how Reelin might regulate neuronal migration by acting on the actin and microtubule cytoskeleton. By binding to ApoER2 receptors on the migrating neurons, Reelin induces stabilization of the leading processes extending toward the marginal zone, which involves Dab1 phosphorylation, adhesion molecule expression, cofilin phosphorylation and inhibition of tau phosphorylation. By binding to VLDLR and integrin receptors, Reelin interacts with Lis1 and induces nuclear translocation, accompanied by the ubiquitination of phosphorylated Dab1. Eventually Reelin induces clustering of its receptors resulting in the endocytosis of a Reelin/receptor complex (particularly VLDLR). The resulting decrease in Reelin contributes to neuronal arrest at the marginal zone.
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Affiliation(s)
- Xuejun Chai
- Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH) , Hamburg, Germany
| | - Michael Frotscher
- Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH) , Hamburg, Germany
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31
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Bock HH, May P. Canonical and Non-canonical Reelin Signaling. Front Cell Neurosci 2016; 10:166. [PMID: 27445693 PMCID: PMC4928174 DOI: 10.3389/fncel.2016.00166] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/08/2016] [Indexed: 12/11/2022] Open
Abstract
Reelin is a large secreted glycoprotein that is essential for correct neuronal positioning during neurodevelopment and is important for synaptic plasticity in the mature brain. Moreover, Reelin is expressed in many extraneuronal tissues; yet the roles of peripheral Reelin are largely unknown. In the brain, many of Reelin's functions are mediated by a molecular signaling cascade that involves two lipoprotein receptors, apolipoprotein E receptor-2 (Apoer2) and very low density-lipoprotein receptor (Vldlr), the neuronal phosphoprotein Disabled-1 (Dab1), and members of the Src family of protein tyrosine kinases as crucial elements. This core signaling pathway in turn modulates the activity of adaptor proteins and downstream protein kinase cascades, many of which target the neuronal cytoskeleton. However, additional Reelin-binding receptors have been postulated or described, either as coreceptors that are essential for the activation of the "canonical" Reelin signaling cascade involving Apoer2/Vldlr and Dab1, or as receptors that activate alternative or additional signaling pathways. Here we will give an overview of canonical and alternative Reelin signaling pathways, molecular mechanisms involved, and their potential physiological roles in the context of different biological settings.
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Affiliation(s)
- Hans H Bock
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
| | - Petra May
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
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