501
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Kim SY, Porter BE, Friedman A, Kaufer D. A potential role for glia-derived extracellular matrix remodeling in postinjury epilepsy. J Neurosci Res 2016; 94:794-803. [PMID: 27265805 DOI: 10.1002/jnr.23758] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 01/04/2023]
Abstract
Head trauma and vascular injuries are known risk factors for acquired epilepsy. The sequence of events that lead from the initial injury to the development of epilepsy involves complex plastic changes and circuit rewiring. In-depth, comprehensive understanding of the epileptogenic process is critical for the identification of disease-modifying targets. Here we review the complex interactions of cellular and extracellular components that may promote epileptogenesis, with an emphasis on the role of astrocytes. Emerging evidence demonstrates that astrocytes promptly respond to brain damage and play a critical role in the development of postinjury epilepsy. Astrocytes have been shown to regulate extracellular matrix (ECM) remodeling, which can affect plasticity and stability of synapses and, in turn, contribute to the epileptogenic process. From these separate lines of evidence, we present a hypothesis suggesting a possible role for astrocyte-regulated remodeling of ECM and perineuronal nets, a specialized ECM structure around fast-spiking inhibitory interneurons, in the development and progression of posttraumatic epilepsies. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Soo Young Kim
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California
| | - Brenda E Porter
- Department of Neurology, Stanford University School of Medicine, Palo Alto, California
| | - Alon Friedman
- Departments of Physiology and Cell Biology, Cognitive and Brain Sciences, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Daniela Kaufer
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California.,Canadian Institute for Advanced Research Program in Child and Brain Development, Toronto, Ontario, Canada
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502
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Abstract
Astrocytes abound in the human central nervous system (CNS) and play a multitude of indispensable roles in neuronal homeostasis and regulation of synaptic plasticity. While traditionally considered to be merely ancillary supportive cells, their complex yet fundamental relevance to brain physiology and pathology have only become apparent in recent times. Beyond their myriad canonical functions, previously unrecognised region-specific functional heterogeneity of astrocytes is emerging as an important attribute and challenges the traditional perspective of CNS-wide astrocyte homogeneity. Animal models have undeniably provided crucial insights into astrocyte biology, yet interspecies differences may limit the translational yield of such studies. Indeed, experimental systems aiming to understand the function of human astrocytes in health and disease have been hampered by accessibility to enriched cultures. Human induced pluripotent stem cells (hiPSCs) now offer an unparalleled model system to interrogate the role of astrocytes in neurodegenerative disorders. By virtue of their ability to convey mutations at pathophysiological levels in a human system, hiPSCs may serve as an ideal pre-clinical platform for both resolution of pathogenic mechanisms and drug discovery. Here, we review astrocyte specification from hiPSCs and discuss their role in modelling human neurological diseases.
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503
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Mayo L, Cunha APD, Madi A, Beynon V, Yang Z, Alvarez JI, Prat A, Sobel RA, Kobzik L, Lassmann H, Quintana FJ, Weiner HL. IL-10-dependent Tr1 cells attenuate astrocyte activation and ameliorate chronic central nervous system inflammation. Brain 2016; 139:1939-57. [PMID: 27246324 PMCID: PMC4939696 DOI: 10.1093/brain/aww113] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 03/21/2016] [Indexed: 01/09/2023] Open
Abstract
See Winger and Zamvil (doi:
10.1093/brain/aww121
) for a scientific commentary on this article.
The innate immune system plays a central role in the chronic central nervous system inflammation that drives neurological disability in progressive forms of multiple sclerosis, for which there are no effective treatments. The mucosal immune system is a unique tolerogenic organ that provides a physiological approach for the induction of regulatory T cells. Here we report that nasal administration of CD3-specific antibody ameliorates disease in a progressive animal model of multiple sclerosis. This effect is IL-10-dependent and is mediated by the induction of regulatory T cells that share a similar transcriptional profile to Tr1 regulatory cells and that suppress the astrocyte inflammatory transcriptional program. Treatment results in an attenuated inflammatory milieu in the central nervous system, decreased microglia activation, reduced recruitment of peripheral monocytes, stabilization of the blood–brain barrier and less neurodegeneration. These findings suggest a new therapeutic approach for the treatment of progressive forms of multiple sclerosis and potentially other types of chronic central nervous system inflammation.
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Affiliation(s)
- Lior Mayo
- 1 Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA 2 Cell Research and Immunology Department, Sagol School of Neuroscience, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 699788, Israel
| | - Andre Pires Da Cunha
- 1 Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Asaf Madi
- 3 Evergrande Center for Immunologic Diseases, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Vanessa Beynon
- 1 Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Zhiping Yang
- 4 Environmental Health Department, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA
| | - Jorge I Alvarez
- 5 Neuroimmunology Research Lab, CRCHUM, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada 6 Pathobiology Department, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexandre Prat
- 5 Neuroimmunology Research Lab, CRCHUM, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
| | | | - Lester Kobzik
- 4 Environmental Health Department, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA
| | - Hans Lassmann
- 8 Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Wien, Austria
| | - Francisco J Quintana
- 1 Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Howard L Weiner
- 1 Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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504
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Enteric nervous system assembly: Functional integration within the developing gut. Dev Biol 2016; 417:168-81. [PMID: 27235816 DOI: 10.1016/j.ydbio.2016.05.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/26/2016] [Accepted: 05/24/2016] [Indexed: 02/08/2023]
Abstract
Co-ordinated gastrointestinal function is the result of integrated communication between the enteric nervous system (ENS) and "effector" cells in the gastrointestinal tract. Unlike smooth muscle cells, interstitial cells, and the vast majority of cell types residing in the mucosa, enteric neurons and glia are not generated within the gut. Instead, they arise from neural crest cells that migrate into and colonise the developing gastrointestinal tract. Although they are "later" arrivals into the developing gut, enteric neural crest-derived cells (ENCCs) respond to many of the same secreted signalling molecules as the "resident" epithelial and mesenchymal cells, and several factors that control the development of smooth muscle cells, interstitial cells and epithelial cells also regulate ENCCs. Much progress has been made towards understanding the migration of ENCCs along the gastrointestinal tract and their differentiation into neurons and glia. However, our understanding of how enteric neurons begin to communicate with each other and extend their neurites out of the developing plexus layers to innervate the various cell types lining the concentric layers of the gastrointestinal tract is only beginning. It is critical for postpartum survival that the gastrointestinal tract and its enteric circuitry are sufficiently mature to cope with the influx of nutrients and their absorption that occurs shortly after birth. Subsequently, colonisation of the gut by immune cells and microbiota during postnatal development has an important impact that determines the ultimate outline of the intrinsic neural networks of the gut. In this review, we describe the integrated development of the ENS and its target cells.
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505
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Kähne T, Richter S, Kolodziej A, Smalla KH, Pielot R, Engler A, Ohl FW, Dieterich DC, Seidenbecher C, Tischmeyer W, Naumann M, Gundelfinger ED. Proteome rearrangements after auditory learning: high-resolution profiling of synapse-enriched protein fractions from mouse brain. J Neurochem 2016; 138:124-38. [PMID: 27062398 PMCID: PMC5089584 DOI: 10.1111/jnc.13636] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 03/23/2016] [Accepted: 04/01/2016] [Indexed: 01/09/2023]
Abstract
Learning and memory processes are accompanied by rearrangements of synaptic protein networks. While various studies have demonstrated the regulation of individual synaptic proteins during these processes, much less is known about the complex regulation of synaptic proteomes. Recently, we reported that auditory discrimination learning in mice is associated with a relative down-regulation of proteins involved in the structural organization of synapses in various brain regions. Aiming at the identification of biological processes and signaling pathways involved in auditory memory formation, here, a label-free quantification approach was utilized to identify regulated synaptic junctional proteins and phosphoproteins in the auditory cortex, frontal cortex, hippocampus, and striatum of mice 24 h after the learning experiment. Twenty proteins, including postsynaptic scaffolds, actin-remodeling proteins, and RNA-binding proteins, were regulated in at least three brain regions pointing to common, cross-regional mechanisms. Most of the detected synaptic proteome changes were, however, restricted to individual brain regions. For example, several members of the Septin family of cytoskeletal proteins were up-regulated only in the hippocampus, while Septin-9 was down-regulated in the hippocampus, the frontal cortex, and the striatum. Meta analyses utilizing several databases were employed to identify underlying cellular functions and biological pathways. Data are available via ProteomeExchange with identifier PXD003089. How does the protein composition of synapses change in different brain areas upon auditory learning? We unravel discrete proteome changes in mouse auditory cortex, frontal cortex, hippocampus, and striatum functionally implicated in the learning process. We identify not only common but also area-specific biological pathways and cellular processes modulated 24 h after training, indicating individual contributions of the regions to memory processing.
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Affiliation(s)
- Thilo Kähne
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Sandra Richter
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Angela Kolodziej
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Institute of Biology, Otto von Guericke University, Magdeburg, Germany
| | - Karl-Heinz Smalla
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Rainer Pielot
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | | | - Frank W Ohl
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Institute of Biology, Otto von Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Daniela C Dieterich
- Center for Behavioral Brain Sciences, Magdeburg, Germany.,Institute of Pharmacology and Toxicology, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Constanze Seidenbecher
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Wolfgang Tischmeyer
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Eckart D Gundelfinger
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Molecular Neuroscience, Medical School, Otto von Guericke University, Magdeburg, Germany.,German Center for Neurodegenerative Diseases, Magdeburg, Germany
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506
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Li J, Zhang L, Chu Y, Namaka M, Deng B, Kong J, Bi X. Astrocytes in Oligodendrocyte Lineage Development and White Matter Pathology. Front Cell Neurosci 2016; 10:119. [PMID: 27242432 PMCID: PMC4861901 DOI: 10.3389/fncel.2016.00119] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 04/25/2016] [Indexed: 01/14/2023] Open
Abstract
White matter is primarily composed of myelin and myelinated axons. Structural and functional completeness of myelin is critical for the reliable and efficient transmission of information. White matter injury has been associated with the development of many demyelinating diseases. Despite a variety of scientific advances aimed at promoting re-myelination, their benefit has proven at best to be marginal. Research suggests that the failure of the re-myelination process may be the result of an unfavorable microenvironment. Astrocytes, are the most ample and diverse type of glial cells in central nervous system (CNS) which display multiple functions for the cells of the oligodendrocytes lineage. As such, much attention has recently been drawn to astrocyte function in terms of white matter myelin repair. They are different in white matter from those in gray matter in specific regards to development, morphology, location, protein expression and other supportive functions. During the process of demyelination and re-myelination, the functions of astrocytes are dynamic in that they are able to change functions in accordance to different time points, triggers or reactive pathways resulting in vastly different biologic effects. They have pivotal effects on oligodendrocytes and other cell types in the oligodendrocyte lineage by serving as an energy supplier, a participant of immunological and inflammatory functions, a source of trophic factors and iron and a sustainer of homeostasis. Astrocytic impairment has been shown to be directly linked to the development of neuromyelities optica (NMO). In addition, astroctyes have also been implicated in other white matter conditions such as psychiatric disorders and neurodegenerative diseases such as Alzheimer’s disease (AD), multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Inhibiting specifically detrimental signaling pathways in astrocytes while preserving their beneficial functions may be a promising approach for remyelination strategies. As such, the ability to manipulate astrocyte function represents a novel therapeutic approach that can repair the damaged myelin that is known to occur in a variety of white matter-related disorders.
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Affiliation(s)
- Jiasi Li
- Department of Neurology, Shanghai Changhai Hospital Shanghai, China
| | - Lei Zhang
- Department of Vascular Surgery, Shanghai Changhai Hospital Shanghai, China
| | - Yongxin Chu
- Department of Vascular Surgery, Affiliated Huai'an Hospital of Xuzhou Medical College Huai'an, China
| | - Michael Namaka
- Faculty of Health Sciences, College of Pharmacy and Medicine, University of Manitoba Winnipeg, MB, Canada
| | - Benqiang Deng
- Department of Neurology, Shanghai Changhai Hospital Shanghai, China
| | - Jiming Kong
- Department of Human Anatomy and Cell Science, University of Manitoba Winnipeg, MB, Canada
| | - Xiaoying Bi
- Department of Neurology, Shanghai Changhai Hospital Shanghai, China
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507
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Astrocytes regulate heterogeneity of presynaptic strengths in hippocampal networks. Proc Natl Acad Sci U S A 2016; 113:E2685-94. [PMID: 27118849 DOI: 10.1073/pnas.1523717113] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Dendrites are neuronal structures specialized for receiving and processing information through their many synaptic inputs. How input strengths are modified across dendrites in ways that are crucial for synaptic integration and plasticity remains unclear. We examined in single hippocampal neurons the mechanism of heterosynaptic interactions and the heterogeneity of synaptic strengths of pyramidal cell inputs. Heterosynaptic presynaptic plasticity that counterbalances input strengths requires N-methyl-d-aspartate receptors (NMDARs) and astrocytes. Importantly, this mechanism is shared with the mechanism for maintaining highly heterogeneous basal presynaptic strengths, which requires astrocyte Ca(2+) signaling involving NMDAR activation, astrocyte membrane depolarization, and L-type Ca(2+) channels. Intracellular infusion of NMDARs or Ca(2+)-channel blockers into astrocytes, conditionally ablating the GluN1 NMDAR subunit, or optogenetically hyperpolarizing astrocytes with archaerhodopsin promotes homogenization of convergent presynaptic inputs. Our findings support the presence of an astrocyte-dependent cellular mechanism that enhances the heterogeneity of presynaptic strengths of convergent connections, which may help boost the computational power of dendrites.
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508
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Carron SF, Yan EB, Alwis DS, Rajan R. Differential susceptibility of cortical and subcortical inhibitory neurons and astrocytes in the long term following diffuse traumatic brain injury. J Comp Neurol 2016; 524:3530-3560. [PMID: 27072754 DOI: 10.1002/cne.24014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 02/02/2023]
Abstract
Long-term diffuse traumatic brain injury (dTBI) causes neuronal hyperexcitation in supragranular layers in sensory cortex, likely through reduced inhibition. Other forms of TBI affect inhibitory interneurons in subcortical areas but it is unknown if this occurs in cortex, or in any brain area in dTBI. We investigated dTBI effects on inhibitory neurons and astrocytes in somatosensory and motor cortex, and hippocampus, 8 weeks post-TBI. Brains were labeled with antibodies against calbindin (CB), parvalbumin (PV), calretinin (CR) and neuropeptide Y (NPY), and somatostatin (SOM) and glial fibrillary acidic protein (GFAP), a marker for astrogliosis during neurodegeneration. Despite persistent behavioral deficits in rotarod performance up to the time of brain extraction (TBI = 73.13 ± 5.23% mean ± SEM, Sham = 92.29 ± 5.56%, P < 0.01), motor cortex showed only a significant increase, in NPY neurons in supragranular layers (mean cells/mm2 ± SEM, Sham = 16 ± 0.971, TBI = 25 ± 1.51, P = 0.001). In somatosensory cortex, only CR+ neurons showed changes, being decreased in supragranular (TBI = 19 ± 1.18, Sham = 25 ± 1.10, P < 0.01) and increased in infragranular (TBI = 28 ± 1.35, Sham = 24 ± 1.07, P < 0.05) layers. Heterogeneous changes were seen in hippocampal staining: CB+ decreased in dentate gyrus (TBI = 2 ± 0.382, Sham = 4 ± 0.383, P < 0.01), PV+ increased in CA1 (TBI = 39 ± 1.26, Sham = 33 ± 1.69, P < 0.05) and CA2/3 (TBI = 26 ± 2.10, Sham = 20 ± 1.49, P < 0.05), and CR+ decreased in CA1 (TBI = 10 ± 1.02, Sham = 14 ± 1.14, P < 0.05). Astrogliosis significantly increased in corpus callosum (TBI = 6.7 ± 0.69, Sham = 2.5 ± 0.38; P = 0.007). While dTBI effects on inhibitory neurons appear region- and type-specific, a common feature in all cases of decrease was that changes occurred in dendrite targeting interneurons involved in neuronal integration. J. Comp. Neurol. 524:3530-3560, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Simone F Carron
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Edwin B Yan
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Dasuni S Alwis
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Ramesh Rajan
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
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509
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Molumby MJ, Keeler AB, Weiner JA. Homophilic Protocadherin Cell-Cell Interactions Promote Dendrite Complexity. Cell Rep 2016; 15:1037-1050. [PMID: 27117416 DOI: 10.1016/j.celrep.2016.03.093] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/16/2016] [Accepted: 03/27/2016] [Indexed: 01/04/2023] Open
Abstract
Growth of a properly complex dendrite arbor is a key step in neuronal differentiation and a prerequisite for neural circuit formation. Diverse cell surface molecules, such as the clustered protocadherins (Pcdhs), have long been proposed to regulate circuit formation through specific cell-cell interactions. Here, using transgenic and conditional knockout mice to manipulate γ-Pcdh repertoire in the cerebral cortex, we show that the complexity of a neuron's dendritic arbor is determined by homophilic interactions with other cells. Neurons expressing only one of the 22 γ-Pcdhs can exhibit either exuberant or minimal dendrite complexity, depending only on whether surrounding cells express the same isoform. Furthermore, loss of astrocytic γ-Pcdhs, or disruption of astrocyte-neuron homophilic matching, reduces dendrite complexity cell non-autonomously. Our data indicate that γ-Pcdhs act locally to promote dendrite arborization via homophilic matching, and they confirm that connectivity in vivo depends on molecular interactions between neurons and between neurons and astrocytes.
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Affiliation(s)
- Michael J Molumby
- Department of Biology, The University of Iowa, Iowa City, IA 52242, USA; Graduate Program in Genetics, The University of Iowa, Iowa City, IA 52242, USA
| | - Austin B Keeler
- Department of Biology, The University of Iowa, Iowa City, IA 52242, USA; Graduate Program in Neuroscience, The University of Iowa, Iowa City, IA 52242, USA
| | - Joshua A Weiner
- Department of Biology, The University of Iowa, Iowa City, IA 52242, USA; Graduate Program in Genetics, The University of Iowa, Iowa City, IA 52242, USA; Graduate Program in Neuroscience, The University of Iowa, Iowa City, IA 52242, USA; Department of Psychiatry, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA.
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510
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Cullen CL, Young KM. How Does Transcranial Magnetic Stimulation Influence Glial Cells in the Central Nervous System? Front Neural Circuits 2016; 10:26. [PMID: 27092058 PMCID: PMC4820444 DOI: 10.3389/fncir.2016.00026] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/23/2016] [Indexed: 12/13/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is widely used in the clinic, and while it has a direct effect on neuronal excitability, the beneficial effects experienced by patients are likely to include the indirect activation of other cell types. Research conducted over the past two decades has made it increasingly clear that a population of non-neuronal cells, collectively known as glia, respond to and facilitate neuronal signaling. Each glial cell type has the ability to respond to electrical activity directly or indirectly, making them likely cellular effectors of TMS. TMS has been shown to enhance adult neural stem and progenitor cell (NSPC) proliferation, but the effect on cell survival and differentiation is less certain. Furthermore there is limited information regarding the response of astrocytes and microglia to TMS, and a complete paucity of data relating to the response of oligodendrocyte-lineage cells to this treatment. However, due to the critical and yet multifaceted role of glial cells in the central nervous system (CNS), the influence that TMS has on glial cells is certainly an area that warrants careful examination.
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Affiliation(s)
- Carlie L. Cullen
- Menzies Institute for Medical Research, University of TasmaniaHobart, TAS, Australia
| | - Kaylene M. Young
- Menzies Institute for Medical Research, University of TasmaniaHobart, TAS, Australia
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511
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Song S, Miranda CJ, Braun L, Meyer K, Frakes AE, Ferraiuolo L, Likhite S, Bevan AK, Foust KD, McConnell MJ, Walker CM, Kaspar BK. Major histocompatibility complex class I molecules protect motor neurons from astrocyte-induced toxicity in amyotrophic lateral sclerosis. Nat Med 2016; 22:397-403. [PMID: 26928464 PMCID: PMC4823173 DOI: 10.1038/nm.4052] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 01/27/2016] [Indexed: 02/08/2023]
Abstract
Astrocytes isolated from individuals with amyotrophic lateral sclerosis (ALS) are toxic to motor neurons (MNs) and play a non-cell autonomous role in disease pathogenesis. The mechanisms underlying the susceptibility of MNs to cell death remain unclear. Here we report that astrocytes derived from either mice bearing mutations in genes associated with ALS or human subjects with ALS reduce the expression of major histocompatibility complex class I (MHCI) molecules on MNs; reduced MHCI expression makes these MNs susceptible to astrocyte-induced cell death. Increasing MHCI expression on MNs increases survival and motor performance in a mouse model of ALS and protects MNs against astrocyte toxicity. Overexpression of a single MHCI molecule, HLA-F, protects human MNs from ALS astrocyte-mediated toxicity, whereas knockdown of its receptor, the killer cell immunoglobulin-like receptor KIR3DL2, on human astrocytes results in enhanced MN death. Thus, our data indicate that, in ALS, loss of MHCI expression on MNs renders them more vulnerable to astrocyte-mediated toxicity.
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Affiliation(s)
- SungWon Song
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio, USA
| | - Carlos J. Miranda
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Lyndsey Braun
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Kathrin Meyer
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Ashley E. Frakes
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, USA
| | - Laura Ferraiuolo
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Shibi Likhite
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio, USA
| | - Adam K. Bevan
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, USA
| | - Kevin D. Foust
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
| | - Michael J. McConnell
- Dept. of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, USA
| | - Christopher M. Walker
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Pediatrics, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, USA
| | - Brian K. Kaspar
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio, USA
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, USA
- Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
- Department of Pediatrics, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio, USA
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512
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Zhao Z, Nelson AR, Betsholtz C, Zlokovic BV. Establishment and Dysfunction of the Blood-Brain Barrier. Cell 2016; 163:1064-1078. [PMID: 26590417 DOI: 10.1016/j.cell.2015.10.067] [Citation(s) in RCA: 1052] [Impact Index Per Article: 131.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 12/11/2022]
Abstract
Structural and functional brain connectivity, synaptic activity, and information processing require highly coordinated signal transduction between different cell types within the neurovascular unit and intact blood-brain barrier (BBB) functions. Here, we examine the mechanisms regulating the formation and maintenance of the BBB and functions of BBB-associated cell types. Furthermore, we discuss the growing evidence associating BBB breakdown with the pathogenesis of inherited monogenic neurological disorders and complex multifactorial diseases, including Alzheimer's disease.
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Affiliation(s)
- Zhen Zhao
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Amy R Nelson
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA
| | - Christer Betsholtz
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, 75185 Uppsala, Sweden
| | - Berislav V Zlokovic
- Department of Physiology and Biophysics and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90089, USA.
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513
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Hu X, Yuan Y, Wang D, Su Z. Heterogeneous astrocytes: Active players in CNS. Brain Res Bull 2016; 125:1-18. [PMID: 27021168 DOI: 10.1016/j.brainresbull.2016.03.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/22/2016] [Accepted: 03/24/2016] [Indexed: 12/12/2022]
Abstract
Astrocytes, the predominant cell type that are broadly distributed in the brain and spinal cord, play key roles in maintaining homeostasis of the central nerve system (CNS) in physiological and pathological conditions. Increasing evidence indicates that astrocytes are a complex colony with heterogeneity on morphology, gene expression, function and many other aspects depending on their spatio-temporal distribution and activation level. In pathological conditions, astrocytes differentially respond to all kinds of insults, including injury and disease, and participate in the neuropathological process. Based on current studies, we here give an overview of the roles of heterogeneous astrocytes in CNS, especially in neuropathologies, which focuses on biological and functional diversity of astrocytes. We propose that a precise understanding of the heterogeneous astrocytes is critical to unlocking the secrets about pathogenesis and treatment of the mazy CNS.
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Affiliation(s)
- Xin Hu
- Institute of Neuroscience and Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, China
| | - Yimin Yuan
- Institute of Neuroscience and Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, China
| | - Dan Wang
- Institute of Neuroscience and Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, China
| | - Zhida Su
- Institute of Neuroscience and Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, China.
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514
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Zhong S, Du Y, Kiyoshi CM, Ma B, Alford CC, Wang Q, Yang Y, Liu X, Zhou M. Electrophysiological behavior of neonatal astrocytes in hippocampal stratum radiatum. Mol Brain 2016; 9:34. [PMID: 27004553 PMCID: PMC4802662 DOI: 10.1186/s13041-016-0213-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/12/2016] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Neonatal astrocytes are diverse in origin, and undergo dramatic change in gene expression, morphological differentiation and syncytial networking throughout development. Neonatal astrocytes also play multifaceted roles in neuronal circuitry establishment. However, the extent to which neonatal astrocytes differ from their counterparts in the adult brain remains unknown. RESULTS Based on ALDH1L1-eGFP expression or sulforhodamine 101 staining, neonatal astrocytes at postnatal day 1-3 can be reliably identified in hippocampal stratum radiatum. They exhibit a more negative resting membrane potential (V M), -85 mV, than mature astrocytes, -80 mV and a variably rectifying whole-cell current profile due to complex expression of voltage-gated outward transient K(+) (IKa), delayed rectifying K(+) (IKd) and inward K(+) (IKin) conductances. Differing from NG2 glia, depolarization-induced inward Na(+) currents (INa) could not be detected in neonatal astrocytes. A quasi-physiological V M of -69 mV was retained when inwardly rectifying Kir4.1 was inhibited by 100 μM Ba(2+) in both wild type and TWIK-1/TREK-1 double gene knockout astrocytes, indicating expression of additional leak K(+) channels yet unknown. In dual patch recording, electrical coupling was detected in 74 % (14/19 pairs) of neonatal astrocytes with largely variable coupling coefficients. The increasing gap junction coupling progressively masked the rectifying K(+) conductances to account for an increasing number of linear voltage-to-current relationship passive astrocytes (PAs). Gap junction inhibition, by 100 μM meclofenamic acid, substantially reduced membrane conductance and converted all the neonatal PAs to variably rectifying astrocytes. The low density expression of leak K(+) conductance in neonatal astrocytes corresponded to a ~50 % less K(+) uptake capacity compared to adult astrocytes. CONCLUSIONS Neonatal astrocytes predominantly express a variety of rectifying K(+) conductances, form discrete cell-to-cell gap junction coupling and are deficient in K(+) homeostatic capacity.
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Affiliation(s)
- Shiying Zhong
- />Department of Neurology, Shanghai 10th Hospital of Tongji University, School of Medicine, 301 Yan Chang Zhong Road, Shanghai, 200072 China
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
| | - Yixing Du
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
| | - Conrad M. Kiyoshi
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
| | - Baofeng Ma
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
| | - Catherine C. Alford
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
| | - Qi Wang
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
| | - Yongjie Yang
- />Department of Neuroscience, Tufts University School of Medicine, Boston, MA USA
| | - Xueyuan Liu
- />Department of Neurology, Shanghai 10th Hospital of Tongji University, School of Medicine, 301 Yan Chang Zhong Road, Shanghai, 200072 China
| | - Min Zhou
- />Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH 43210 USA
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515
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Lu Z, Piechowicz M, Qiu S. A Simplified Method for Ultra-Low Density, Long-Term Primary Hippocampal Neuron Culture. J Vis Exp 2016. [PMID: 27022758 DOI: 10.3791/53797] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Culturing primary hippocampal neurons in vitro facilitates mechanistic interrogation of many aspects of neuronal development. Dissociated embryonic hippocampal neurons can often grow successfully on glass coverslips at high density under serum-free conditions, but low density cultures typically require a supply of trophic factors by co-culturing them with a glia feeder layer, preparation of which can be time-consuming and laborious. In addition, the presence of glia may confound interpretation of results and preclude studies on neuron-specific mechanisms. Here, a simplified method is presented for ultra-low density (~2,000 neurons/cm2), long-term (>3 months) primary hippocampal neuron culture that is under serum free conditions and without glia cell support. Low density neurons are grown on poly-D-lysine coated coverslips, and flipped on high density neurons grown in a 24-well plate. Instead of using paraffin dots to create a space between the two neuronal layers, the experimenters can simply etch the plastic bottom of the well, on which the high density neurons reside, to create a microspace conducive to low density neuron growth. The co-culture can be easily maintained for >3 months without significant loss of low density neurons, thus facilitating the morphological and physiological study of these neurons. To illustrate this successful culture condition, data are provided to show profuse synapse formation in low density cells after prolonged culture. This co-culture system also facilitates the survival of sparse individual neurons grown in islands of poly-D-lysine substrates and thus the formation of autaptic connections.
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Affiliation(s)
- Zhongming Lu
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix; Jiangsu Provincial Center for Disease Control and Prevention
| | - Mariel Piechowicz
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix
| | - Shenfeng Qiu
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix;
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516
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Abstract
Glia account for more than half of the cells in the mammalian nervous system, and the past few decades have witnessed a flood of studies that detail novel functions for glia in nervous system development, plasticity and disease. Here, and in the accompanying poster, we review the origins of glia and discuss their diverse roles during development, in the adult nervous system and in the context of disease.
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Affiliation(s)
- J Bradley Zuchero
- Department of Neurobiology, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University, School of Medicine, Stanford, CA 94305, USA
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517
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To WT, Hart J, De Ridder D, Vanneste S. Considering the influence of stimulation parameters on the effect of conventional and high-definition transcranial direct current stimulation. Expert Rev Med Devices 2016; 13:391-404. [DOI: 10.1586/17434440.2016.1153968] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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518
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Peco E, Davla S, Camp D, Stacey SM, Landgraf M, van Meyel DJ. Drosophila astrocytes cover specific territories of the CNS neuropil and are instructed to differentiate by Prospero, a key effector of Notch. Development 2016; 143:1170-81. [PMID: 26893340 DOI: 10.1242/dev.133165] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/08/2016] [Indexed: 01/13/2023]
Abstract
Astrocytes are crucial in the formation, fine-tuning, function and plasticity of neural circuits in the central nervous system. However, important questions remain about the mechanisms instructing astrocyte cell fate. We have studied astrogenesis in the ventral nerve cord of Drosophila larvae, where astrocytes exhibit remarkable morphological and molecular similarities to those in mammals. We reveal the births of larval astrocytes from a multipotent glial lineage, their allocation to reproducible positions, and their deployment of ramified arbors to cover specific neuropil territories to form a stereotyped astroglial map. Finally, we unraveled a molecular pathway for astrocyte differentiation in which the Ets protein Pointed and the Notch signaling pathway are required for astrogenesis; however, only Notch is sufficient to direct non-astrocytic progenitors toward astrocytic fate. We found that Prospero is a key effector of Notch in this process. Our data identify an instructive astrogenic program that acts as a binary switch to distinguish astrocytes from other glial cells.
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Affiliation(s)
- Emilie Peco
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H3G 1A4 Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada H3G 1A4
| | - Sejal Davla
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H3G 1A4 McGill Integrated Program in Neuroscience McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Darius Camp
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H3G 1A4 Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada H3A 1A3
| | - Stephanie M Stacey
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H3G 1A4 McGill Integrated Program in Neuroscience McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Matthias Landgraf
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Don J van Meyel
- Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H3G 1A4 Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada H3G 1A4
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519
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Zhu YB, Gao W, Zhang Y, Jia F, Zhang HL, Liu YZ, Sun XF, Yin Y, Yin DM. Astrocyte-derived phosphatidic acid promotes dendritic branching. Sci Rep 2016; 6:21096. [PMID: 26883475 PMCID: PMC4756377 DOI: 10.1038/srep21096] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 01/18/2016] [Indexed: 01/24/2023] Open
Abstract
Astrocytes play critical roles in neural circuit formation and function. Recent studies have revealed several secreted and contact-mediated signals from astrocytes which are essential for neurite outgrowth and synapse formation. However, the mechanisms underlying the regulation of dendritic branching by astrocytes remain elusive. Phospholipase D1 (PLD1), which catalyzes the hydrolysis of phosphatidylcholine (PC) to generate phosphatidic acid (PA) and choline, has been implicated in the regulation of neurite outgrowth. Here we showed that knockdown of PLD1 selectively in astrocytes reduced dendritic branching of neurons in neuron-glia mixed culture. Further studies from sandwich-like cocultures and astrocyte conditioned medium suggested that astrocyte PLD1 regulated dendritic branching through secreted signals. We later demonstrated that PA was the key mediator for astrocyte PLD1 to regulate dendritic branching. Moreover, PA itself was sufficient to promote dendritic branching of neurons. Lastly, we showed that PA could activate protein kinase A (PKA) in neurons and promote dendritic branching through PKA signaling. Taken together, our results demonstrate that astrocyte PLD1 and its lipid product PA are essential regulators of dendritic branching in neurons. These results may provide new insight into mechanisms underlying how astrocytes regulate dendrite growth of neurons.
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Affiliation(s)
- Yan-Bing Zhu
- Laboratories of Stem Cell Biology and Regenerative Medicine, Department of Neurology, Experimental Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Weizhen Gao
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yongbo Zhang
- Laboratories of Stem Cell Biology and Regenerative Medicine, Department of Neurology, Experimental Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Feng Jia
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hai-Long Zhang
- Key Laboratory of Brain Functional Genomics, Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics, School of Life Sciences, East China Normal University, Shanghai, China
| | - Ying-Zi Liu
- Key Laboratory of Brain Functional Genomics, Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics, School of Life Sciences, East China Normal University, Shanghai, China
| | - Xue-Fang Sun
- Key Laboratory of Brain Functional Genomics, Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics, School of Life Sciences, East China Normal University, Shanghai, China
| | - Yuhua Yin
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dong-Min Yin
- Key Laboratory of Brain Functional Genomics, Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics, School of Life Sciences, East China Normal University, Shanghai, China
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520
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Abstract
A cardinal feature of early stages of human brain development centers on the sensory, cognitive, and emotional experiences that shape neuronal-circuit formation and refinement. Consequently, alterations in these processes account for many psychiatric and neurodevelopmental disorders. Neurodevelopment disorders affect 3-4% of the world population. The impact of these disorders presents a major challenge to clinicians, geneticists, and neuroscientists. Mutations that cause neurodevelopmental disorders are commonly found in genes encoding proteins that regulate synaptic function. Investigation of the underlying mechanisms using gain or loss of function approaches has revealed alterations in dendritic spine structure, function, and plasticity, consequently modulating the neuronal circuit formation and thereby raising the possibility of neurodevelopmental disorders resulting from synaptopathies. One such gene, SYNGAP1 (Synaptic Ras-GTPase-activating protein) has been shown to cause Intellectual Disability (ID) with comorbid Autism Spectrum Disorder (ASD) and epilepsy in children. SYNGAP1 is a negative regulator of Ras, Rap and of AMPA receptor trafficking to the postsynaptic membrane, thereby regulating not only synaptic plasticity, but also neuronal homeostasis. Recent studies on the neurophysiology of SYNGAP1, using Syngap1 mouse models, have provided deeper insights into how downstream signaling proteins and synaptic plasticity are regulated by SYNGAP1. This knowledge has led to a better understanding of the function of SYNGAP1 and suggests a potential target during critical period of development when the brain is more susceptible to therapeutic intervention.
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Affiliation(s)
- Nallathambi Jeyabalan
- Narayana Nethralaya Post-Graduate Institute of Ophthalmology, Narayana Nethralaya Foundation, Narayana Health City Bangalore, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bangalore, India
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521
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Petrelli F, Pucci L, Bezzi P. Astrocytes and Microglia and Their Potential Link with Autism Spectrum Disorders. Front Cell Neurosci 2016; 10:21. [PMID: 26903806 PMCID: PMC4751265 DOI: 10.3389/fncel.2016.00021] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/19/2016] [Indexed: 01/09/2023] Open
Abstract
The cellular mechanism(s) underlying autism spectrum disorders (ASDs) are not fully understood although it has been shown that various genetic and environmental factors contribute to their etiology. As increasing evidence indicates that astrocytes and microglial cells play a major role in synapse maturation and function, and there is evidence of deficits in glial cell functions in ASDs, one current hypothesis is that glial dysfunctions directly contribute to their pathophysiology. The aim of this review is to summarize microglia and astrocyte functions in synapse development and their contributions to ASDs.
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Affiliation(s)
| | | | - Paola Bezzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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522
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Xing L, Li X, Snider WD. Neurodevelopment. "RASopathic" astrocytes constrain neural plasticity. Science 2016; 348:636-7. [PMID: 25953994 DOI: 10.1126/science.aab3738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Lei Xing
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Xiaoyan Li
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - William D Snider
- UNC Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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523
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Krencik R, Hokanson KC, Narayan AR, Dvornik J, Rooney GE, Rauen KA, Weiss LA, Rowitch DH, Ullian EM. Dysregulation of astrocyte extracellular signaling in Costello syndrome. Sci Transl Med 2016; 7:286ra66. [PMID: 25947161 DOI: 10.1126/scitranslmed.aaa5645] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Astrocytes produce an assortment of signals that promote neuronal maturation according to a precise developmental timeline. Is this orchestrated timing and signaling altered in human neurodevelopmental disorders? To address this question, the astroglial lineage was investigated in two model systems of a developmental disorder with intellectual disability caused by mutant Harvey rat sarcoma viral oncogene homolog (HRAS) termed Costello syndrome: mutant HRAS human induced pluripotent stem cells (iPSCs) and transgenic mice. Human iPSCs derived from patients with Costello syndrome differentiated to astroglia more rapidly in vitro than those derived from wild-type cell lines with normal HRAS, exhibited hyperplasia, and also generated an abundance of extracellular matrix remodeling factors and proteoglycans. Acute treatment with a farnesyl transferase inhibitor and knockdown of the transcription factor SNAI2 reduced expression of several proteoglycans in Costello syndrome iPSC-derived astrocytes. Similarly, mice in which mutant HRAS was expressed selectively in astrocytes exhibited experience-independent increased accumulation of perineuronal net proteoglycans in cortex, as well as increased parvalbumin expression in interneurons, when compared to wild-type mice. Our data indicate that astrocytes expressing mutant HRAS dysregulate cortical maturation during development as shown by abnormal extracellular matrix remodeling and implicate excessive astrocyte-to-neuron signaling as a possible drug target for treating mental impairment and enhancing neuroplasticity.
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Affiliation(s)
- Robert Krencik
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Kenton C Hokanson
- Neuroscience Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Aditi R Narayan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jill Dvornik
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Gemma E Rooney
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Katherine A Rauen
- Department of Pediatrics, University of California, Davis, Sacramento, CA 95817, USA
| | - Lauren A Weiss
- Department of Psychiatry and Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David H Rowitch
- Department of Pediatrics, Eli and Edythe Broad Institute for Regenerative Medicine and Stem Cell Research, and Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Erik M Ullian
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA. Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA.
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524
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Petrelli F, Bezzi P. Novel insights into gliotransmitters. Curr Opin Pharmacol 2016; 26:138-45. [DOI: 10.1016/j.coph.2015.11.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 11/20/2015] [Accepted: 11/23/2015] [Indexed: 12/13/2022]
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525
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Sudo G, Kagawa T, Kokubu Y, Inazawa J, Taga T. Increase in GFAP-positive astrocytes in histone demethylase GASC1/KDM4C/JMJD2C hypomorphic mutant mice. Genes Cells 2016; 21:218-25. [PMID: 26805559 DOI: 10.1111/gtc.12331] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 11/27/2015] [Indexed: 01/06/2023]
Abstract
GASC1, also known as KDM4C/JMJD2C, is a histone demethylase for histone H3 lysine 9 (H3K9) and H3K36. In this study, we observed an increase of GFAP-positive astrocytes in the brain of Gasc1 hypomorphic mutant mice at 2-3 months of age, but not at postnatal day 14 and day 30 by immunohistochemistry. Increases of GFAP-positive astrocytes were widely observed in the forebrain and prominent in such regions as cerebral cortex, caudate putamen, amygdala and diencephalon, but not obvious in hippocampus. Taken together with our observations to be published elsewhere that Gasc1 hypomorphic mutant mice exhibit abnormal behaviors including hyperactivity, persistence and many types of learning and memory deficits and abnormal synaptic functions such as prolonged long-term potentiation, the increase in GFAP-positive astrocytes may help understand their phenotypes, because astrocytes are known to affect synaptic plasticity.
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Affiliation(s)
- Genki Sudo
- Department of Stem Cell regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Tetsushi Kagawa
- Department of Stem Cell regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Yasuhiro Kokubu
- Department of Stem Cell regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Johji Inazawa
- Department of Molecular Cytogenetics, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Tetsuya Taga
- Department of Stem Cell regulation, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
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526
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Lee HR, Farhanullah, Lee J, Jajoo R, Kong SY, Shin JY, Kim JO, Lee J, Lee J, Kim HJ. Discovery of a Small Molecule that Enhances Astrocytogenesis by Activation of STAT3, SMAD1/5/8, and ERK1/2 via Induction of Cytokines in Neural Stem Cells. ACS Chem Neurosci 2016; 7:90-9. [PMID: 26505647 DOI: 10.1021/acschemneuro.5b00243] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Identification of small molecules that direct neural stem cells (NSCs) into specific cell types would be helpful to understand the molecular mechanisms involved in regulation of NSC fate, and facilitate the development of therapeutic applications. In the current study, we developed and screened small molecules that can modulate the fate of NSCs that are derived from rat fetal cortex. Among these compounds, compounds 5 and 6 successfully differentiated NSCs into astrocytes and neurons, respectively. Compound 5 induced astrocytogenesis by increasing expression of interleukin-6, bone morphogenetic protein 2 and leukemia inhibitory factor and through consequent phosphorylation of signal transducer and activator of transcription 3 and Sma- and Mad-related protein 1/5/8 in NSCs. In addition, compound 5 increased the expression of fibroblast growth factor (FGF) 2 and FGF8 which may regulate the branching and morphology of astrocytes. Taken together, our results suggest that these small molecules can serve as a useful tool to study cell fate determination in NSCs and be used as an inexpensive alternative to cytokines to study mechanisms of astrocytogenesis.
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Affiliation(s)
- Ha-Rim Lee
- College
of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Farhanullah
- GVK Bioscience Pvt
Ltd, Hyderabad-500076, India
| | - JiSoo Lee
- College
of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Rahul Jajoo
- GVK Bioscience Pvt
Ltd, Hyderabad-500076, India
| | - Sun-Young Kong
- College
of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Jae-Yeon Shin
- College
of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Jae-Ouk Kim
- Laboratory
Science Division, International Vaccine Institute, Seoul 151-919, Korea
| | - Jiyoun Lee
- Department
of Global Medical Science, Sungshin University, Seoul 142-732, Korea
| | - Jeewoo Lee
- College
of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Hyun-Jung Kim
- College
of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
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527
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Cherra SJ, Jin Y. A Two-Immunoglobulin-Domain Transmembrane Protein Mediates an Epidermal-Neuronal Interaction to Maintain Synapse Density. Neuron 2016; 89:325-36. [PMID: 26777275 PMCID: PMC4871750 DOI: 10.1016/j.neuron.2015.12.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 08/17/2015] [Accepted: 12/08/2015] [Indexed: 02/06/2023]
Abstract
Synaptic maintenance is essential for neural circuit function. In the C. elegans locomotor circuit, motor neurons are in direct contact with the epidermis. Here, we reveal a novel epidermal-neuronal interaction mediated by a two-immunoglobulin domain transmembrane protein, ZIG-10, that is necessary for maintaining cholinergic synapse density. ZIG-10 is localized at the cell surface of epidermis and cholinergic motor neurons, with high levels at areas adjacent to synapses. Loss of zig-10 increases the number of cholinergic excitatory synapses and exacerbates convulsion behavior in a seizure model. Mis-expression of zig-10 in GABAergic inhibitory neurons reduces GABAergic synapse number, dependent on the presence of ZIG-10 in the epidermis. Furthermore, ZIG-10 interacts with the tyrosine kinase SRC-2 to regulate the phagocytic activity of the epidermis to restrict cholinergic synapse number. Our studies demonstrate the highly specific roles of non-neuronal cells in modulating neural circuit function, through neuron-type-specific maintenance of synapse density.
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Affiliation(s)
- Salvatore J. Cherra
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yishi Jin
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
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528
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New Insights on Astrocyte Ion Channels: Critical for Homeostasis and Neuron-Glia Signaling. J Neurosci 2016; 35:13827-35. [PMID: 26468182 DOI: 10.1523/jneurosci.2603-15.2015] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Initial biophysical studies on glial cells nearly 50 years ago identified these cells as being electrically silent. These first studies also demonstrated a large K(+) conductance, which led to the notion that glia may regulate extracellular K(+) levels homeostatically. This view has now gained critical support from the study of multiple disease models discussed herein. Dysfunction of a major astrocyte K(+) channel, Kir4.1, appears as an early pathological event underlying neuronal phenotypes in several neurodevelopmental and neurodegenerative diseases. An expanding list of other astrocyte ion channels, including the calcium-activated ion channel BEST-1, hemichannels, and two-pore domain K(+) channels, all contribute to astrocyte biology and CNS function and underpin new forms of crosstalk between neurons and glia. Once considered merely the glue that holds the brain together, it is now increasingly recognized that astrocytes contribute in several fundamental ways to neuronal function. Emerging new insights and future perspectives of this active research area are highlighted within. SIGNIFICANCE STATEMENT The critical role of astrocyte potassium channels in CNS homeostasis has been reemphasized by recent studies conducted in animal disease models. Emerging evidence also supports the signaling role mediated by astrocyte ion channels such as BEST1, hemichannels, and two-pore channels, which enable astrocytes to interact with neurons and regulate synaptic transmission and plasticity. This minisymposium highlights recent developments and future perspectives of these research areas.
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529
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Beta-hydroxy-beta-methylbutyrate ameliorates aging effects in the dendritic tree of pyramidal neurons in the medial prefrontal cortex of both male and female rats. Neurobiol Aging 2016; 40:78-85. [PMID: 26973106 DOI: 10.1016/j.neurobiolaging.2016.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 01/08/2016] [Accepted: 01/09/2016] [Indexed: 11/22/2022]
Abstract
Beta-hydroxy-beta-methylbutyrate (HMB), a supplement commonly used to maintain muscle in elderly and clinical populations, has been unexplored in the aging brain. In both healthy aging humans and rat models, there are cognitive deficits associated with age-related dendritic shrinkage within the prefrontal cortex. The present study explores the effects of relatively short- and long-term (7 and 31 weeks) oral HMB supplementation starting at 12 months of age in male and female rats on the dendritic tree of layer 5 pyramidal neurons in the medial prefrontal cortex. Since female rats continue to secrete ovarian hormones after reaching reproductive senescence, middle-aged female rats were ovariectomized to model humans. As expected, there were fewer spines and a retraction of dendritic material in the apical and basilar trees in old age controls of both sexes compared with their middle-aged counterparts. However, these losses did not occur in the HMB-treated rats in either dendrites or the total number of dendritic spines. Thus, HMB forestalled the effects of aging on the dendritic tree of this population of neurons.
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530
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Grigorovsky V, Bardakjian BL. Balance of synaptic and electrotonic connections controls the excitability of networks in biophysical model of epilepsy. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:4709-12. [PMID: 26737345 DOI: 10.1109/embc.2015.7319445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent studies have implicated astrocytes in multiple active roles in neuronal networks. In particular they have been shown to be able to moderate and alter neural firing patterns both in normal and epileptic conditions. In addition, it has been proposed that one of the roles of gap junctions between astrocytes, as well as neurons is in increasing synchronization of neuronal firing and potential epileptogenic effect. In this study we build upon a model of a network that incorporates both pyramidal cells and interneurons as well as astrocytes with potassium clearance mechanisms and basic calcium dynamics. We include electrotonic connections between cells to be able to separate the effects of synaptic connections and gap junctions on neuronal hyperexcitability. Preliminary findings of this model show that under normal conditions, when gap junctions are blocked the network exists in an interictal-like state. When the system is put in a zero calcium environment (i.e. synaptic connections are disabled), the network enters spontaneous rhythmic bursting with very regular spiking. This suggests that electrotonic connections play a crucial role in the epileptogenesis within the neuronal network.
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Neuron-Glia Interactions in Neural Plasticity: Contributions of Neural Extracellular Matrix and Perineuronal Nets. Neural Plast 2016; 2016:5214961. [PMID: 26881114 PMCID: PMC4736403 DOI: 10.1155/2016/5214961] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/10/2015] [Indexed: 11/17/2022] Open
Abstract
Synapses are specialized structures that mediate rapid and efficient signal transmission between neurons and are surrounded by glial cells. Astrocytes develop an intimate association with synapses in the central nervous system (CNS) and contribute to the regulation of ion and neurotransmitter concentrations. Together with neurons, they shape intercellular space to provide a stable milieu for neuronal activity. Extracellular matrix (ECM) components are synthesized by both neurons and astrocytes and play an important role in the formation, maintenance, and function of synapses in the CNS. The components of the ECM have been detected near glial processes, which abut onto the CNS synaptic unit, where they are part of the specialized macromolecular assemblies, termed perineuronal nets (PNNs). PNNs have originally been discovered by Golgi and represent a molecular scaffold deposited in the interface between the astrocyte and subsets of neurons in the vicinity of the synapse. Recent reports strongly suggest that PNNs are tightly involved in the regulation of synaptic plasticity. Moreover, several studies have implicated PNNs and the neural ECM in neuropsychiatric diseases. Here, we highlight current concepts relating to neural ECM and PNNs and describe an in vitro approach that allows for the investigation of ECM functions for synaptogenesis.
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532
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Astrocyte Dysfunction in Developmental Neurometabolic Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 949:227-243. [PMID: 27714692 DOI: 10.1007/978-3-319-40764-7_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Astrocytes play crucial roles in maintaining brain homeostasis and in orchestrating neural development, all through tightly coordinated steps that cooperate to maintain the balance needed for normal development. Here, we review the alterations in astrocyte functions that contribute to a variety of developmental neurometabolic disorders and provide additional data on the predominant role of astrocyte dysfunction in the neurometabolic neurodegenerative disease glutaric acidemia type I. Finally, we describe some of the therapeutical approaches directed to neurometabolic diseases and discuss if astrocytes can be possible therapeutic targets for treating these disorders.
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533
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Yang L, Zhang Y, Guldner IH, Zhang S, Chen DZ. 3D Segmentation of Glial Cells Using Fully Convolutional Networks and k-Terminal Cut. MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION – MICCAI 2016 2016. [DOI: 10.1007/978-3-319-46723-8_76] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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534
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Astrocytes as Pharmacological Targets in the Treatment of Schizophrenia. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2016. [DOI: 10.1016/b978-0-12-800981-9.00025-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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535
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Verkhratsky A, Parpura V. Astrogliopathology in neurological, neurodevelopmental and psychiatric disorders. Neurobiol Dis 2016; 85:254-261. [PMID: 25843667 PMCID: PMC4592688 DOI: 10.1016/j.nbd.2015.03.025] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/20/2015] [Accepted: 03/26/2015] [Indexed: 12/17/2022] Open
Abstract
Astroglial cells represent a main element in the maintenance of homeostasis and providing defense to the brain. Consequently, their dysfunction underlies many, if not all, neurological, neurodevelopmental and neuropsychiatric disorders. General astrogliopathy is evident in diametrically opposing morpho-functional changes in astrocytes, i.e. their hypertrophy along with reactivity or atrophy with asthenia. Neurological disorders with astroglial participation can be genetic, of which Alexander disease is a primary sporadic astrogliopathy, environmentally caused, such as heavy metal encephalopathies, or neurodevelopmental in origin. Astroglia contribute to neurodegenerative processes seen in amyotrophic lateral sclerosis, Alzheimer's and Huntington's diseases. Furthermore, astroglia also play a role in major neuropsychiatric disorders, ranging from schizophrenia to depression, as well as in addictive disorders.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories, University of Alabama at Birmingham, 1719 6th Avenue South, CIRC 429, Birmingham, AL 35294-0021, USA; Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka, Croatia.
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536
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Stary C. Exploring and exploiting unique properties of the hippocampal dentate gyrus for post-stroke therapy: astrocytes link ischemic resistance with neurogenic potential. Neural Regen Res 2016; 11:1756-1757. [PMID: 28123412 PMCID: PMC5204224 DOI: 10.4103/1673-5374.194714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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537
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Verkhratsky A, Zorec R, Rodriguez JJ, Parpura V. PATHOBIOLOGY OF NEURODEGENERATION: THE ROLE FOR ASTROGLIA. OPERA MEDICA ET PHYSIOLOGICA 2016; 1:13-22. [PMID: 27308639 PMCID: PMC4905715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The common denominator of neurodegenerative diseases, which mainly affect humans, is the progressive death of neural cells resulting in neurological and cognitive deficits. Astroglial cells are the central elements of the homoeostasis, defence and regeneration of the central nervous system, and their malfunction or reactivity contribute to the pathophysiology of neurodegenerative diseases. Pathological remodelling of astroglia in neurodegenerative context is multifaceted. Both astroglial atrophy with a loss of function and astroglial reactivity have been identified in virtually all the forms of neurodegenerative disorders. Astroglia may represent a novel target for therapeutic strategies aimed at preventing and possibly curing neurodegenerative diseases.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK
- University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain & Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain
| | - Robert Zorec
- University of Ljubljana, Institute of Pathophysiology, Laboratory of Neuroendocrinology and Molecular Cell Physiology, Zaloska cesta 4; SI-1000, Ljubljana, Slovenia
- Celica, BIOMEDICAL, Technology Park 24, 1000 Ljubljana, Slovenia
| | - Jose J. Rodriguez
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain & Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories, 1719 6th Avenue South, CIRC 429, University of Alabama, Birmingham, AL 35294-0021, USA
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538
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Li Y, Li D, Raisman G. Astrocytic role in synapse formation after injury. Brain Res 2015; 1645:18-21. [PMID: 26746338 DOI: 10.1016/j.brainres.2015.12.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 12/19/2015] [Indexed: 01/24/2023]
Abstract
In 1969 a paper entitled Neuronal plasticity in the septal nuclei of the adult rat proposed that new synapses are formed in the adult brain after injury (Raisman, 1969). The quantitative electron microscopic study of the timed responses to selective partial denervation of the neuropil of the adult rat septal nuclei after distant transection of the hippocampal efferent axons in the fimbria showed that the new synapses arise by sprouting of surviving adjacent synapses which selectively take over the previously denervated sites and thus restore the number of synapses to normal. This article presents the evidence for the role of perisynaptic astrocytic processes in the removal and formation of synapses and considers its significance as one of the three major divisions of the astrocytic surface in terms of the axonal responses to injury and regeneration. This article is part of a Special Issue entitled SI:50th Anniversary Issue.
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Affiliation(s)
- Ying Li
- Spinal Repair Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom.
| | - Daqing Li
- Spinal Repair Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom.
| | - Geoffrey Raisman
- Spinal Repair Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom.
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539
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Reactive Transformation and Increased BDNF Signaling by Hippocampal Astrocytes in Response to MK-801. PLoS One 2015; 10:e0145651. [PMID: 26700309 PMCID: PMC4689377 DOI: 10.1371/journal.pone.0145651] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 12/07/2015] [Indexed: 11/26/2022] Open
Abstract
MK-801, also known as dizocilpine, is a noncompetitive N-methyl-D-aspartic acid (NMDA) receptor antagonist that induces schizophrenia-like symptoms. While astrocytes have been implicated in the pathophysiology of psychiatric disorders, including schizophrenia, astrocytic responses to MK-801 and their significance to schizotypic symptoms are unclear. Changes in the expression levels of glial fibrillary acid protein (GFAP), a marker of astrocyte activation in response to a variety of pathogenic stimuli, were examined in the hippocampus of rats treated with the repeated MK-801 injection (0.5 mg/10ml/kg body weight for 6 days) and in primary cultured hippocampal astrocytes incubated with MK-801 (5 or 20 μM for 24 h). Moreover, the expression levels of BDNF and its receptors TrkB and p75 were examined in MK-801-treated astrocyte cultures. MK-801 treatment enhanced GFAP expression in the rat hippocampus and also increased the levels of GFAP protein and mRNA in hippocampal astrocytes in vitro. Treatment of cultured hippocampal astrocytes with MK-801 enhanced protein and mRNA levels of BDNF, TrkB, and p75. Collectively, our results suggest that hippocampal astrocytes may contribute to the pathophysiology of schizophrenia symptoms associated with NMDA receptor hypofunction by reactive transformation and altered BDNF signaling.
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540
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Astrocytes Protect against Isoflurane Neurotoxicity by Buffering pro-brain-derived Neurotrophic Factor. Anesthesiology 2015; 123:810-9. [PMID: 26270940 DOI: 10.1097/aln.0000000000000824] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Isoflurane induces cell death in neurons undergoing synaptogenesis via increased production of pro-brain-derived neurotrophic factor (proBDNF) and activation of postsynaptic p75 neurotrophin receptor (p75). Astrocytes express p75, but their role in neuronal p75-mediated cell death remains unclear. The authors investigated whether astrocytes have the capacity to buffer increases in proBDNF and protect against isoflurane/p75 neurotoxicity. METHODS Cell death was assessed in day in vitro (DIV) 7 mouse primary neuronal cultures alone or in co-culture with age-matched or DIV 21 astrocytes with propidium iodide 24 h after 1 h exposure to 2% isoflurane or recombinant proBDNF. Astrocyte-targeted knockdown of p75 in co-culture was achieved with small-interfering RNA and astrocyte-specific transfection reagent and verified with immunofluorescence microscopy. proBDNF levels were assessed by enzyme-linked immunosorbent assay. Each experiment used six to eight replicate cultures/condition and was repeated at least three times. RESULTS Exposure to isoflurane significantly (P < 0.05) increased neuronal cell death in primary neuronal cultures (1.5 ± 0.7 fold, mean ± SD) but not in co-culture with DIV 7 (1.0 ± 0.5 fold) or DIV 21 astrocytes (1.2 ± 1.2 fold). Exogenous proBDNF dose dependently induced neuronal cell death in both primary neuronal and co-cultures, an effect enhanced by astrocyte p75 inhibition. Astrocyte-targeted p75 knockdown in co-cultures increased media proBDNF (1.2 ± 0.1 fold) and augmented isoflurane-induced neuronal cell death (3.8 ± 3.1 fold). CONCLUSIONS The presence of astrocytes provides protection to growing neurons by buffering increased levels of proBDNF induced by isoflurane. These findings may hold clinical significance for the neonatal and injured brain where increased levels of proBDNF impair neurogenesis.
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541
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Zhang Y, Sloan SA, Clarke LE, Caneda C, Plaza CA, Blumenthal PD, Vogel H, Steinberg GK, Edwards MSB, Li G, Duncan JA, Cheshier SH, Shuer LM, Chang EF, Grant GA, Gephart MGH, Barres BA. Purification and Characterization of Progenitor and Mature Human Astrocytes Reveals Transcriptional and Functional Differences with Mouse. Neuron 2015; 89:37-53. [PMID: 26687838 DOI: 10.1016/j.neuron.2015.11.013] [Citation(s) in RCA: 1464] [Impact Index Per Article: 162.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 10/05/2015] [Accepted: 11/04/2015] [Indexed: 12/11/2022]
Abstract
The functional and molecular similarities and distinctions between human and murine astrocytes are poorly understood. Here, we report the development of an immunopanning method to acutely purify astrocytes from fetal, juvenile, and adult human brains and to maintain these cells in serum-free cultures. We found that human astrocytes have abilities similar to those of murine astrocytes in promoting neuronal survival, inducing functional synapse formation, and engulfing synaptosomes. In contrast to existing observations in mice, we found that mature human astrocytes respond robustly to glutamate. Next, we performed RNA sequencing of healthy human astrocytes along with astrocytes from epileptic and tumor foci and compared these to human neurons, oligodendrocytes, microglia, and endothelial cells (available at http://www.brainrnaseq.org). With these profiles, we identified novel human-specific astrocyte genes and discovered a transcriptome-wide transformation between astrocyte precursor cells and mature post-mitotic astrocytes. These data represent some of the first cell-type-specific molecular profiles of the healthy and diseased human brain.
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Affiliation(s)
- Ye Zhang
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Steven A Sloan
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laura E Clarke
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Christine Caneda
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Colton A Plaza
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Paul D Blumenthal
- Department of Obstetrics and Gynecology, Stanford University Medical Center, Stanford, CA 94305, USA
| | - Hannes Vogel
- Department of Pathology, Stanford University Medical Center, Stanford, CA 94305, USA
| | - Gary K Steinberg
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - Michael S B Edwards
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - Gordon Li
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - John A Duncan
- Department of Pediatric Neurosciences, Kaiser Permanente Santa Clara Medical Center, Santa Clara, CA 95051, USA
| | - Samuel H Cheshier
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - Lawrence M Shuer
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - Edward F Chang
- UCSF Epilepsy Center, University of California, San Francisco, 400 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Gerald A Grant
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - Melanie G Hayden Gephart
- Department of Neurosurgery, Lucile Packard Children's Hospital and Stanford University Medical Center, Stanford, CA 94305, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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542
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Risher ML, Sexton HG, Risher WC, Wilson WA, Fleming RL, Madison RD, Moore SD, Eroglu C, Swartzwelder HS. Adolescent Intermittent Alcohol Exposure: Dysregulation of Thrombospondins and Synapse Formation are Associated with Decreased Neuronal Density in the Adult Hippocampus. Alcohol Clin Exp Res 2015; 39:2403-13. [PMID: 26537975 PMCID: PMC4712076 DOI: 10.1111/acer.12913] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/22/2015] [Indexed: 01/18/2023]
Abstract
BACKGROUND Adolescent intermittent alcohol exposure (AIE) has profound effects on neuronal function. We have previously shown that AIE causes aberrant hippocampal structure and function that persists into adulthood. However, the possible contributions of astrocytes and their signaling factors remain largely unexplored. We investigated the acute and enduring effects of AIE on astrocytic reactivity and signaling on synaptic expression in the hippocampus, including the impact of the thrombospondin (TSP) family of astrocyte-secreted synaptogenic factors and their neuronal receptor, alpha2delta-1 (α2δ-1). Our hypothesis is that some of the influences of AIE on neuronal function may be secondary to direct effects on astrocytes. METHODS We conducted Western blot analysis on TSPs 1 to 4 and α2δ-1 from whole hippocampal lysates 24 hours after the 4th and 10th doses of AIE, then 24 days after the last dose (in adulthood). We used immunohistochemistry to assess astrocyte reactivity (i.e., morphology) and synaptogenesis (i.e., colocalization of pre- and postsynaptic puncta). RESULTS Adolescent AIE reduced α2δ-1 expression, and colocalized pre- and postsynaptic puncta after the fourth ethanol (EtOH) dose. By the 10th dose, increased TSP2 levels were accompanied by an increase in colocalized pre- and postsynaptic puncta, while α2δ-1 returned to control levels. Twenty-four days after the last EtOH dose (i.e., adulthood), TSP2, TSP4, and α2δ-1 expression were all elevated. Astrocyte reactivity, indicated by increased astrocytic volume and area, was also observed at that time. CONCLUSIONS Repeated EtOH exposure during adolescence results in long-term changes in specific astrocyte signaling proteins and their neuronal synaptogenic receptor. Continued signaling by these traditionally developmental factors in adulthood may represent a compensatory mechanism whereby astrocytes reopen the synaptogenic window and repair lost connectivity, and consequently contribute to the enduring maladaptive structural and functional abnormalities previously observed in the hippocampus after AIE.
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Affiliation(s)
- Mary-Louise Risher
- Durham VA Medical Center, Duke University Medical Center, Durham, North Carolina
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Hannah G Sexton
- Durham VA Medical Center, Duke University Medical Center, Durham, North Carolina
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - W Christopher Risher
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
| | - Wilkie A Wilson
- Social Sciences Research Institute, Duke University Medical Center, Durham, North Carolina
| | - Rebekah L Fleming
- Durham VA Medical Center, Duke University Medical Center, Durham, North Carolina
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Roger D Madison
- Durham VA Medical Center, Duke University Medical Center, Durham, North Carolina
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina
| | - Scott D Moore
- Durham VA Medical Center, Duke University Medical Center, Durham, North Carolina
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
| | - H Scott Swartzwelder
- Durham VA Medical Center, Duke University Medical Center, Durham, North Carolina
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
- Department of Psychology and Neuroscience, Duke University Medical Center, Durham, North Carolina
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543
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Wiese S, Faissner A. The role of extracellular matrix in spinal cord development. Exp Neurol 2015; 274:90-9. [DOI: 10.1016/j.expneurol.2015.05.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/13/2015] [Accepted: 05/25/2015] [Indexed: 01/06/2023]
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544
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Bartol TM, Bromer C, Kinney J, Chirillo MA, Bourne JN, Harris KM, Sejnowski TJ. Nanoconnectomic upper bound on the variability of synaptic plasticity. eLife 2015; 4:e10778. [PMID: 26618907 PMCID: PMC4737657 DOI: 10.7554/elife.10778] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/29/2015] [Indexed: 12/15/2022] Open
Abstract
Information in a computer is quantified by the number of bits that can be stored and recovered. An important question about the brain is how much information can be stored at a synapse through synaptic plasticity, which depends on the history of probabilistic synaptic activity. The strong correlation between size and efficacy of a synapse allowed us to estimate the variability of synaptic plasticity. In an EM reconstruction of hippocampal neuropil we found single axons making two or more synaptic contacts onto the same dendrites, having shared histories of presynaptic and postsynaptic activity. The spine heads and neck diameters, but not neck lengths, of these pairs were nearly identical in size. We found that there is a minimum of 26 distinguishable synaptic strengths, corresponding to storing 4.7 bits of information at each synapse. Because of stochastic variability of synaptic activation the observed precision requires averaging activity over several minutes. DOI:http://dx.doi.org/10.7554/eLife.10778.001 What is the memory capacity of a human brain? The storage capacity in a computer memory is measured in bits, each of which can have a value of 0 or 1. In the brain, information is stored in the form of synaptic strength, a measure of how strongly activity in one neuron influences another neuron to which it is connected. The number of different strengths can be measured in bits. The total storage capacity of the brain therefore depends on both the number of synapses and the number of distinguishable synaptic strengths. Structurally, neurons consist of a cell body that influences other neurons through a cable-like axon. The cell body bears numerous short branches called dendrites, which are covered in tiny protrusions, or “spines”. Most excitatory synapses are formed between the axon of one neuron and a dendritic spine on another. When two neurons on either side of a synapse are active simultaneously, that synapse becomes stronger, a form of memory. The dendritic spine also becomes larger to accommodate the extra molecular machinery needed to support a stronger synapse. Some axons form two or more synapses with the same dendrite, but on different dendritic spines. These synapses should be the same strength because they will have experienced the same history of neural activity. Bartol et al. used a technique called serial section electron microscopy to create a 3D reconstruction of part of the brain that allowed the sizes of the dendritic spines these synapses form on to be compared. This revealed that the synaptic areas and volumes of the spine heads were nearly identical. This remarkable similarity can be used to estimate the number of bits of information that a single synapse can store, since the size of dendritic spines and their synapses can be used as proxies for synaptic strength. Measurements in a small cube of brain tissue revealed 26 different dendritic spine sizes, each associated with a distinct synaptic strength. This number translates into a storage capacity of roughly 4.7 bits of information per synapse. This estimate is markedly higher than previous suggestions. It implies that the total memory capacity of the brain – with its many trillions of synapses – may have been underestimated by an order of magnitude. Additional measurements in the same and other brain regions are needed to confirm this possibility. DOI:http://dx.doi.org/10.7554/eLife.10778.002
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Affiliation(s)
- Thomas M Bartol
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Cailey Bromer
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Justin Kinney
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, United States
| | - Michael A Chirillo
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, United States
| | - Jennifer N Bourne
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, United States
| | - Kristen M Harris
- Center for Learning and Memory, Department of Neuroscience, The University of Texas at Austin, Austin, United States
| | - Terrence J Sejnowski
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,Division of Biological Sciences, University of California, San Diego, San Diego, United States
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545
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Ibi D, Yamada K. Therapeutic Targets for Neurodevelopmental Disorders Emerging from Animal Models with Perinatal Immune Activation. Int J Mol Sci 2015; 16:28218-29. [PMID: 26633355 PMCID: PMC4691039 DOI: 10.3390/ijms161226092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 11/17/2015] [Accepted: 11/20/2015] [Indexed: 01/02/2023] Open
Abstract
Increasing epidemiological evidence indicates that perinatal infection with various viral pathogens enhances the risk for several psychiatric disorders. The pathophysiological significance of astrocyte interactions with neurons and/or gut microbiomes has been reported in neurodevelopmental disorders triggered by pre- and postnatal immune insults. Recent studies with the maternal immune activation or neonatal polyriboinosinic polyribocytidylic acid models of neurodevelopmental disorders have identified various candidate molecules that could be responsible for brain dysfunction. Here, we review the functions of several candidate molecules in neurodevelopment and brain function and discuss their potential as therapeutic targets for psychiatric disorders.
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Affiliation(s)
- Daisuke Ibi
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, 150 Yagotoyama, Tenpaku-ku, Nagoya 468-8503, Japan.
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya 466-8560, Japan.
| | - Kiyofumi Yamada
- Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya 466-8560, Japan.
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546
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Back and forth in time: Directing age in iPSC-derived lineages. Brain Res 2015; 1656:14-26. [PMID: 26592774 DOI: 10.1016/j.brainres.2015.11.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 10/19/2015] [Accepted: 11/10/2015] [Indexed: 02/07/2023]
Abstract
The advent of induced pluripotent stem cells (iPSC) has transformed the classic approach of studying human disease, providing in vitro access to disease-relevant cells from patients for the study of disease pathogenesis and for drug screening. However, in spite of the broad repertoire of iPSC-based disease models developed in recent years, increasing evidence suggests that this technology might not be fully suitable for the study of conditions of old age, such as neurodegeneration. The difficulty in recapitulating late-stage features of disease in cells of pluripotent origin is believed to be a discrepancy between the fetal-like nature of iPSC-progeny and the advanced age of onset of neurodegenerative syndromes. In parallel to the issue of functional immaturity known to affect derivatives of pluripotent cells, latest findings suggest that reprogramming also subjects cells to a process of "rejuvenation", giving rise to cells that are too "young" to manifest phenotypes of age-related diseases. Thus, following the significant progress in manipulating cellular fate, the stem cell field will now have to face the new challenge of controlling cellular age, in order to fully harness the potential of iPSC-technology to advance the research and cure of diseases of the aging brain. This article is part of a Special Issue entitled SI: Exploiting human neurons.
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547
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Loss of Local Astrocyte Support Disrupts Action Potential Propagation and Glutamate Release Synchrony from Unmyelinated Hippocampal Axon Terminals In Vitro. J Neurosci 2015; 35:11105-17. [PMID: 26245971 DOI: 10.1523/jneurosci.1289-15.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Neuron-astrocyte interactions are critical for proper CNS development and function. Astrocytes secrete factors that are pivotal for synaptic development and function, neuronal metabolism, and neuronal survival. Our understanding of this relationship, however, remains incomplete due to technical hurdles that have prevented the removal of astrocytes from neuronal circuits without changing other important conditions. Here we overcame this obstacle by growing solitary rat hippocampal neurons on microcultures that were comprised of either an astrocyte bed (+astrocyte) or a collagen bed (-astrocyte) within the same culture dish. -Astrocyte autaptic evoked EPSCs, but not IPSCs, displayed an altered temporal profile, which included increased synaptic delay, increased time to peak, and severe glutamate release asynchrony, distinct from previously described quantal asynchrony. Although we observed minimal alteration of the somatically recorded action potential waveform, action potential propagation was altered. We observed a longer latency between somatic initiation and arrival at distal locations, which likely explains asynchronous EPSC peaks, and we observed broadening of the axonal spike, which likely underlies changes to evoked EPSC onset. No apparent changes in axon structure were observed, suggesting altered axonal excitability. In conclusion, we propose that local astrocyte support has an unappreciated role in maintaining glutamate release synchrony by disturbing axonal signal propagation. SIGNIFICANCE STATEMENT Certain glial cell types (oligodendrocytes, Schwann cells) facilitate the propagation of neuronal electrical signals, but a role for astrocytes has not been identified despite many other functions of astrocytes in supporting and modulating neuronal signaling. Under identical global conditions, we cultured neurons with or without local astrocyte support. Without local astrocytes, glutamate transmission was desynchronized by an alteration of the waveform and arrival time of axonal action potentials to synaptic terminals. GABA transmission was not disrupted. The disruption did not involve detectable morphological changes to axons of glutamate neurons. Our work identifies a developmental role for astrocytes in the temporal precision of excitatory signals.
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548
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Chung WS, Welsh CA, Barres BA, Stevens B. Do glia drive synaptic and cognitive impairment in disease? Nat Neurosci 2015; 18:1539-1545. [PMID: 26505565 PMCID: PMC4739631 DOI: 10.1038/nn.4142] [Citation(s) in RCA: 267] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/05/2015] [Indexed: 02/06/2023]
Abstract
Synaptic dysfunction is a hallmark of many neurodegenerative and psychiatric brain disorders, yet we know little about the mechanisms that underlie synaptic vulnerability. Although neuroinflammation and reactive gliosis are prominent in virtually every CNS disease, glia are largely viewed as passive responders to neuronal damage rather than drivers of synaptic dysfunction. This perspective is changing with the growing realization that glia actively signal with neurons and influence synaptic development, transmission and plasticity through an array of secreted and contact-dependent signals. We propose that disruptions in neuron-glia signaling contribute to synaptic and cognitive impairment in disease. Illuminating the mechanisms by which glia influence synapse function may lead to the development of new therapies and biomarkers for synaptic dysfunction.
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Affiliation(s)
- Won-Suk Chung
- Department of Neurobiology, Stanford University School of Medicine, Palo Alto, California 94305, USA
| | - Christina A Welsh
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Palo Alto, California 94305, USA
| | - Beth Stevens
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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549
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A multiplier-less digital design of a bio-inspired stimulator to suppress synchronized regime in a large-scale, sparsely connected neural network. Neural Comput Appl 2015. [DOI: 10.1007/s00521-015-2071-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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550
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Fukushima K, Miura Y, Sawada K, Yamazaki K, Ito M. Establishment of a Human Neuronal Network Assessment System by Using a Human Neuron/Astrocyte Co-Culture Derived from Fetal Neural Stem/Progenitor Cells. ACTA ACUST UNITED AC 2015; 21:54-64. [PMID: 26482803 DOI: 10.1177/1087057115610055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/14/2015] [Indexed: 11/17/2022]
Abstract
Using human cell models mimicking the central nervous system (CNS) provides a better understanding of the human CNS, and it is a key strategy to improve success rates in CNS drug development. In the CNS, neurons function as networks in which astrocytes play important roles. Thus, an assessment system of neuronal network functions in a co-culture of human neurons and astrocytes has potential to accelerate CNS drug development. We previously demonstrated that human hippocampus-derived neural stem/progenitor cells (HIP-009 cells) were a novel tool to obtain human neurons and astrocytes in the same culture. In this study, we applied HIP-009 cells to a multielectrode array (MEA) system to detect neuronal signals as neuronal network functions. We observed spontaneous firings of HIP-009 neurons, and validated functional formation of neuronal networks pharmacologically. By using this assay system, we investigated effects of several reference compounds, including agonists and antagonists of glutamate and γ-aminobutyric acid receptors, and sodium, potassium, and calcium channels, on neuronal network functions using firing and burst numbers, and synchrony as readouts. These results indicate that the HIP-009/MEA assay system is applicable to the pharmacological assessment of drug candidates affecting synaptic functions for CNS drug development.
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Affiliation(s)
- Kazuyuki Fukushima
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Yuji Miura
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Kohei Sawada
- Biopharmaceutical Assessment CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Kazuto Yamazaki
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
| | - Masashi Ito
- Next Generation Systems CFU, Eisai Product Creation Systems, Eisai Co., Ltd., Tokodai, Tsukuba, Ibaraki, Japan
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