1
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Martínez San Segundo P, Pérez González APL, Velasco CD, Llobet A. Protocol to correlate electron microscopy with electrophysiology in single-cell autaptic microcultures. STAR Protoc 2024; 5:103003. [PMID: 38735041 PMCID: PMC11101974 DOI: 10.1016/j.xpro.2024.103003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/26/2024] [Accepted: 03/22/2024] [Indexed: 05/14/2024] Open
Abstract
Single-cell microcultures (SCMs) form a monosynaptic circuit that allows stimulation and recording of postsynaptic responses using a single electrode. Here, we present a protocol to establish autaptic cultures from rat superior cervical ganglion neurons. We describe the steps for preparing SCMs, recording synaptic currents, and identifying and processing the recorded neurons for electron microscopy. We then detail procedures for visualizing synapses. This protocol is illustrated by correlating evoked and spontaneous neurotransmitter release with the ultrastructural features of synapses recorded. For complete details on the use and execution of this protocol, please refer to Velasco et al.1.
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Affiliation(s)
- Pablo Martínez San Segundo
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain; Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Anna Priscil la Pérez González
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Cecilia D Velasco
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain; Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain; Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
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2
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Ji Q, Zhu H, Qin Y, Zhang R, Wang L, Zhang E, Zhou X, Meng R. GP60 and SPARC as albumin receptors: key targeted sites for the delivery of antitumor drugs. Front Pharmacol 2024; 15:1329636. [PMID: 38323081 PMCID: PMC10844528 DOI: 10.3389/fphar.2024.1329636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/08/2024] [Indexed: 02/08/2024] Open
Abstract
Albumin is derived from human or animal blood, and its ability to bind to a large number of endogenous or exogenous biomolecules makes it an ideal drug carrier. As a result, albumin-based drug delivery systems are increasingly being studied. With these in mind, detailed studies of the transport mechanism of albumin-based drug carriers are particularly important. As albumin receptors, glycoprotein 60 (GP60) and secreted protein acidic and rich in cysteine (SPARC) play a crucial role in the delivery of albumin-based drug carriers. GP60 is expressed on vascular endothelial cells and enables albumin to cross the vascular endothelial cell layer, and SPARC is overexpressed in many types of tumor cells, while it is minimally expressed in normal tissue cells. Thus, this review supplements existing articles by detailing the research history and specific biological functions of GP60 or SPARC and research advances in the delivery of antitumor drugs using albumin as a carrier. Meanwhile, the deficiencies and future perspectives in the study of the interaction of albumin with GP60 and SPARC are also pointed out.
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Affiliation(s)
- Qingzhi Ji
- School of Pharmacy, Yancheng Teachers University, Yancheng, China
| | - Huimin Zhu
- Sheyang County Comprehensive Inspection and Testing Center, Yancheng, China
| | - Yuting Qin
- School of Pharmacy, Yancheng Teachers University, Yancheng, China
| | - Ruiya Zhang
- Department of Immunology, Medical School, Nantong University, Nantong, China
| | - Lei Wang
- Department of Immunology, Medical School, Nantong University, Nantong, China
| | - Erhao Zhang
- Department of Immunology, Medical School, Nantong University, Nantong, China
| | - Xiaorong Zhou
- Department of Immunology, Medical School, Nantong University, Nantong, China
| | - Run Meng
- Department of Immunology, Medical School, Nantong University, Nantong, China
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3
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Yang X, Tohda C. Diosgenin restores memory function via SPARC-driven axonal growth from the hippocampus to the PFC in Alzheimer's disease model mice. Mol Psychiatry 2023; 28:2398-2411. [PMID: 37085711 PMCID: PMC10611574 DOI: 10.1038/s41380-023-02052-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 04/23/2023]
Abstract
Central nervous system axons have minimal capacity to regenerate in adult brains, hindering memory recovery in Alzheimer's disease (AD). Although recent studies have shown that damaged axons sprouted in adult and AD mouse brains, long-distance axonal re-innervation to their targets has not been achieved. We selectively visualized axon-growing neurons in the neural circuit for memory formation, from the hippocampus to the prefrontal cortex, and showed that damaged axons successfully extended to their native projecting area in mouse models of AD (5XFAD) by administration of an axonal regenerative agent, diosgenin. In vivo transcriptome analysis detected the expression profile of axon-growing neurons directly isolated from the hippocampus of 5XFAD mice. Secreted protein acidic and rich in cysteine (SPARC) was the most expressed gene in axon-growing neurons. Neuron-specific overexpression of SPARC via adeno-associated virus serotype 9 delivery in the hippocampus recovered memory deficits and axonal projection to the prefrontal cortex in 5XFAD mice. DREADDs (Designer receptors exclusively activated by designer drugs) analyses revealed that SPARC overexpression-induced axonal growth in the 5XFAD mouse brain directly contributes to memory recovery. Elevated levels of SPARC on axonal membranes interact with extracellular rail-like collagen type I to promote axonal remodeling along their original tracings in primary cultured hippocampal neurons. These findings suggest that SPARC-driven axonal growth in the brain may be a promising therapeutic strategy for AD and other neurodegenerative diseases.
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Affiliation(s)
- Ximeng Yang
- Section of Neuromedical Science, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Chihiro Tohda
- Section of Neuromedical Science, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
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4
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Astrocytes regulate neuronal network activity by mediating synapse remodeling. Neurosci Res 2023; 187:3-13. [PMID: 36170922 DOI: 10.1016/j.neures.2022.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 11/22/2022]
Abstract
Based on experience during our life, neuronal connectivity continuously changes through structural remodeling of synapses. Recent studies have shown that the complex interaction between astrocytes and synapses regulates structural synapse remodeling by inducing the formation and elimination of synapses, as well as their functional maturation. Defects in this astrocyte-mediated synapse remodeling cause problems in not only neuronal network activities but also animal behaviors. Moreover, in various neurological disorders, astrocytes have been shown to play central roles in the initiation and progression of synaptic pathophysiology through impaired interactions with synapses. In this review, we will discuss recent studies identifying the novel roles of astrocytes in neuronal circuit remodeling, focusing on synapse formation and elimination. We will also discuss the potential implication of defective astrocytic function in evoking various brain disorders.
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5
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Extracellular matrix and synapse formation. Biosci Rep 2023; 43:232259. [PMID: 36503961 PMCID: PMC9829651 DOI: 10.1042/bsr20212411] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 11/08/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022] Open
Abstract
The extracellular matrix (ECM) is a complex molecular network distributed throughout the extracellular space of different tissues as well as the neuronal system. Previous studies have identified various ECM components that play important roles in neuronal maturation and signal transduction. ECM components are reported to be involved in neurogenesis, neuronal migration, and axonal growth by interacting or binding to specific receptors. In addition, the ECM is found to regulate synapse formation, the stability of the synaptic structure, and synaptic plasticity. Here, we mainly reviewed the effects of various ECM components on synapse formation and briefly described the related diseases caused by the abnormality of several ECM components.
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6
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Cohen LD, Ziv T, Ziv NE. Synapse integrity and function: Dependence on protein synthesis and identification of potential failure points. Front Mol Neurosci 2022; 15:1038614. [PMID: 36583084 PMCID: PMC9792512 DOI: 10.3389/fnmol.2022.1038614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/07/2022] [Indexed: 12/14/2022] Open
Abstract
Synaptic integrity and function depend on myriad proteins - labile molecules with finite lifetimes that need to be continually replaced with freshly synthesized copies. Here we describe experiments designed to expose synaptic (and neuronal) properties and functions that are particularly sensitive to disruptions in protein supply, identify proteins lost early upon such disruptions, and uncover potential, yet currently underappreciated failure points. We report here that acute suppressions of protein synthesis are followed within hours by reductions in spontaneous network activity levels, impaired oxidative phosphorylation and mitochondrial function, and, importantly, destabilization and loss of both excitatory and inhibitory postsynaptic specializations. Conversely, gross impairments in presynaptic vesicle recycling occur over longer time scales (days), as does overt cell death. Proteomic analysis identified groups of potentially essential 'early-lost' proteins including regulators of synapse stability, proteins related to bioenergetics, fatty acid and lipid metabolism, and, unexpectedly, numerous proteins involved in Alzheimer's disease pathology and amyloid beta processing. Collectively, these findings point to neuronal excitability, energy supply and synaptic stability as early-occurring failure points under conditions of compromised supply of newly synthesized protein copies.
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Affiliation(s)
- Laurie D. Cohen
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Haifa, Israel
| | - Tamar Ziv
- Smoler Proteomics Center, Lokey Interdisciplinary Center for Life Sciences & Engineering, Technion, Haifa, Israel
| | - Noam E. Ziv
- Technion Faculty of Medicine, Rappaport Institute and Network Biology Research Laboratories, Haifa, Israel,*Correspondence: Noam E. Ziv,
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7
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Heras-Romero Y, Morales-Guadarrama A, Santana-Martínez R, Ponce I, Rincón-Heredia R, Poot-Hernández AC, Martínez-Moreno A, Urrieta E, Bernal-Vicente BN, Campero-Romero AN, Moreno-Castilla P, Greig NH, Escobar ML, Concha L, Tovar-Y-Romo LB. Improved post-stroke spontaneous recovery by astrocytic extracellular vesicles. Mol Ther 2022; 30:798-815. [PMID: 34563674 PMCID: PMC8821969 DOI: 10.1016/j.ymthe.2021.09.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 09/08/2021] [Accepted: 09/20/2021] [Indexed: 02/04/2023] Open
Abstract
Spontaneous recovery after a stroke accounts for a significant part of the neurological recovery in patients. However limited, the spontaneous recovery is mechanistically driven by axonal restorative processes for which several molecular cues have been previously described. We report the acceleration of spontaneous recovery in a preclinical model of ischemia/reperfusion in rats via a single intracerebroventricular administration of extracellular vesicles released from primary cortical astrocytes. We used magnetic resonance imaging and confocal and multiphoton microscopy to correlate the structural remodeling of the corpus callosum and striatocortical circuits with neurological performance during 21 days. We also evaluated the functionality of the corpus callosum by repetitive recordings of compound action potentials to show that the recovery facilitated by astrocytic extracellular vesicles was both anatomical and functional. Our data provide compelling evidence that astrocytes can hasten the basal recovery that naturally occurs post-stroke through the release of cellular mediators contained in extracellular vesicles.
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Affiliation(s)
- Yessica Heras-Romero
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Axayacatl Morales-Guadarrama
- Departmento de Ingeniería Eléctrica, Universidad Autónoma Metropolitana Iztapalapa, Mexico City, Mexico; National Center for Medical Imaging and Instrumentation Research, Mexico City, Mexico
| | - Ricardo Santana-Martínez
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Isaac Ponce
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Ruth Rincón-Heredia
- Microscopy Core Unit, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Augusto César Poot-Hernández
- Bioinformatics Core Unit, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Araceli Martínez-Moreno
- Divisíon de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Esteban Urrieta
- Divisíon de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Berenice N Bernal-Vicente
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Aura N Campero-Romero
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Perla Moreno-Castilla
- Laboratory of Neurocognitive Aging, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Nigel H Greig
- Drug Design & Development Section, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Martha L Escobar
- Divisíon de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis Concha
- Department of Behavioral and Cognitive Neurobiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, Mexico
| | - Luis B Tovar-Y-Romo
- Department of Molecular Neuropathology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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8
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Milbocker KA, Campbell TS, Collins N, Kim S, Smith IF, Roth TL, Klintsova AY. Glia-Driven Brain Circuit Refinement Is Altered by Early-Life Adversity: Behavioral Outcomes. Front Behav Neurosci 2021; 15:786234. [PMID: 34924972 PMCID: PMC8678604 DOI: 10.3389/fnbeh.2021.786234] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022] Open
Abstract
Early-life adversity (ELA), often clinically referred to as "adverse childhood experiences (ACE)," is the exposure to stress-inducing events in childhood that can result in poor health outcomes. ELA negatively affects neurodevelopment in children and adolescents resulting in several behavioral deficits and increasing the risk of developing a myriad of neuropsychiatric disorders later in life. The neurobiological mechanisms by which ELA alters neurodevelopment in childhood have been the focus of numerous reviews. However, a comprehensive review of the mechanisms affecting adolescent neurodevelopment (i.e., synaptic pruning and myelination) is lacking. Synaptic pruning and myelination are glia-driven processes that are imperative for brain circuit refinement during the transition from adolescence to adulthood. Failure to optimize brain circuitry between key brain structures involved in learning and memory, such as the hippocampus and prefrontal cortex, leads to the emergence of maladaptive behaviors including increased anxiety or reduced executive function. As such, we review preclinical and clinical literature to explore the immediate and lasting effects of ELA on brain circuit development and refinement. Finally, we describe a number of therapeutic interventions best-suited to support adolescent neurodevelopment in children with a history of ELA.
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Affiliation(s)
| | | | | | | | | | | | - Anna Y. Klintsova
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
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9
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Terni B, Llobet A. Axon terminals control endolysosome diffusion to support synaptic remodelling. Life Sci Alliance 2021; 4:4/8/e202101105. [PMID: 34226200 PMCID: PMC8321675 DOI: 10.26508/lsa.202101105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 11/27/2022] Open
Abstract
Endolysosomes present in the presynaptic terminal move by diffusion constrained by F-actin and increase their mobility during the remodelling of synaptic connectivity to support a local degradative activity. Endolysosomes are acidic organelles formed by the fusion of endosomes with lysosomes. In the presynaptic compartment they contribute to protein homeostasis, the maintenance of vesicle pools and synaptic stability. Here, we evaluated the mobility of endolysosomes found in axon terminals of olfactory sensory neurons of Xenopus tropicalis tadpoles. F-actin restricts the motion of these presynaptic acidic organelles which is characterized by a diffusion coefficient of 6.7 × 10−3 μm2·s−1. Local injection of secreted protein acidic and rich in cysteine (SPARC) in the glomerular layer of the olfactory bulb disrupts the structure of synaptic F-actin patches and increases the presence and mobility of endolysosomal organelles found in axon terminals. The increased motion of endolysosomes is localized to the presynaptic compartment and does not promote their access to axonal regions for retrograde transportation to the cell body. Local activation of synaptic degradation mechanisms mediated by SPARC coincides with a loss of the ability of tadpoles to detect waterborne odorants. Together, these observations show that the diffusion of presynaptic endolysosomes increases during conditions of synaptic remodelling to support their local degradative activity.
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Affiliation(s)
- Beatrice Terni
- Department of Pathology and Experimental Therapy, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain .,Laboratory of Neurobiology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Artur Llobet
- Department of Pathology and Experimental Therapy, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain .,Laboratory of Neurobiology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
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10
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Shan L, Zhang T, Fan K, Cai W, Liu H. Astrocyte-Neuron Signaling in Synaptogenesis. Front Cell Dev Biol 2021; 9:680301. [PMID: 34277621 PMCID: PMC8284252 DOI: 10.3389/fcell.2021.680301] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 06/14/2021] [Indexed: 01/10/2023] Open
Abstract
Astrocytes are the key component of the central nervous system (CNS), serving as pivotal regulators of neuronal synapse formation and maturation through their ability to dynamically and bidirectionally communicate with synapses throughout life. In the past 20 years, numerous astrocyte-derived molecules promoting synaptogenesis have been discovered. However, our understanding of the cell biological basis underlying intra-neuron processes and astrocyte-mediated synaptogenesis is still in its infancy. Here, we provide a comprehensive overview of the various ways astrocytes talk to neurons, and highlight astrocytes’ heterogeneity that allow them to displays regional-specific capabilities in boosting synaptogenesis. Finally, we conclude with promises and future directions on how organoids generated from human induced pluripotent stem cells (hiPSCs) effectively address the signaling pathways astrocytes employ in synaptic development.
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Affiliation(s)
- Lili Shan
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Tongran Zhang
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Kevin Fan
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Weibo Cai
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States
| | - Huisheng Liu
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
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11
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Rodrigues-Amorim D, Rivera-Baltanás T, Fernández-Palleiro P, Iglesias-Martínez-Almeida M, Freiría-Martínez L, Jarmardo-Rodriguez C, Del Carmen Vallejo-Curto M, Álvarez-Ariza M, López-García M, de Las Heras E, García-Caballero A, Olivares JM, Spuch C. Changes in the Brain Extracellular Matrix Composition in schizophrenia: A Pathophysiological Dysregulation and a Potential Therapeutic Target. Cell Mol Neurobiol 2021; 42:1921-1932. [PMID: 33712885 DOI: 10.1007/s10571-021-01073-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/01/2021] [Indexed: 11/28/2022]
Abstract
The brain extracellular matrix (ECM) is involved in crucial processes of neural support, neuronal and synaptic plasticity, extrasynaptic transmission, and neurotransmission. ECM is a tridimensional fibrillary meshwork composed of macromolecules that determine its bioactivity and give it unique characteristics. The characterization of the brain ECM is critical to understand its dynamic in SZ. Thus, a comparative study was developed with 71 patients with schizophrenia (SZ) and 70 healthy controls. Plasma of participants was analysed by label-free liquid chromatography-tandem mass spectrometry, and the results were validated using the classical western blot method. Lastly, immunostaining of post-mortem human brain tissue was performed to analyse the distribution of the brain ECM proteins by confocal microscopy. The analysis identified four proteins: fibronectin, lumican, nidogen-1, and secreted protein acidic and rich in cysteine (SPARC) as components of the brain ECM. Statistical significance was found for fibronectin (P = 0.0166), SPARC (P = 0.0003), lumican (P = 0.0012), and nidogen-1 (P < 0.0001) that were decreased in the SZ group. Fluorescence imaging of prefrontal cortex (PFC) sections revealed a lower expression of ECM proteins in SZ. Our study proposes a pathophysiological dysregulation of proteins of the brain ECM, whose abnormal composition leads to a progressive neuronal impairment and consequently to neurodegenerative processes due to lack of neurophysiological support and dysregulation of neuronal homeostasis. Moreover, the brain ECM and its components are potential pharmacological targets to develop new therapeutic approaches to treat SZ.
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Affiliation(s)
- Daniela Rodrigues-Amorim
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Tania Rivera-Baltanás
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Patricia Fernández-Palleiro
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Marta Iglesias-Martínez-Almeida
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Luis Freiría-Martínez
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Cynthia Jarmardo-Rodriguez
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - María Del Carmen Vallejo-Curto
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - María Álvarez-Ariza
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Marta López-García
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Elena de Las Heras
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - Alejandro García-Caballero
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain
| | - José Manuel Olivares
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain.
- Head of Department of Psychiatry, Galicia Sur Health Research Institute - IISGS, Hospital Álvaro Cunqueiro, Estrada Clara Campoamor, 341, Vigo, Spain.
| | - Carlos Spuch
- Translational Neuroscience Research Group, Galicia Sur Health Research Institute, University of Vigo, CIBERSAM, Hospital Álvaro Cunqueiro, Bloque Técnico, Planta 2, Sala de Investigación, Estrada Clara Campoamor, 341, 36212, Vigo, Spain.
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12
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Interplay between hevin, SPARC, and MDGAs: Modulators of neurexin-neuroligin transsynaptic bridges. Structure 2021; 29:664-678.e6. [PMID: 33535026 DOI: 10.1016/j.str.2021.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/20/2020] [Accepted: 01/08/2021] [Indexed: 12/18/2022]
Abstract
Hevin is secreted by astrocytes and its synaptogenic effects are antagonized by the related protein, SPARC. Hevin stabilizes neurexin-neuroligin transsynaptic bridges in vivo. A third protein, membrane-tethered MDGA, blocks these bridges. Here, we reveal the molecular underpinnings of a regulatory network formed by this trio of proteins. The hevin FS-EC structure differs from SPARC, in that the EC domain appears rearranged around a conserved core. The FS domain is structurally conserved and it houses nanomolar affinity binding sites for neurexin and neuroligin. SPARC also binds neurexin and neuroligin, competing with hevin, so its antagonist action is rooted in its shortened N-terminal region. Strikingly, the hevin FS domain competes with MDGA for an overlapping binding site on neuroligin, while the hevin EC domain binds the extracellular matrix protein collagen (like SPARC), so that this trio of proteins can regulate neurexin-neuroligin transsynaptic bridges and also extracellular matrix interactions, impacting synapse formation and ultimately neural circuits.
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13
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Mazaré N, Oudart M, Cohen-Salmon M. Local translation in perisynaptic and perivascular astrocytic processes - a means to ensure astrocyte molecular and functional polarity? J Cell Sci 2021; 134:237323. [PMID: 33483366 DOI: 10.1242/jcs.251629] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Together with the compartmentalization of mRNAs in distal regions of the cytoplasm, local translation constitutes a prominent and evolutionarily conserved mechanism mediating cellular polarization and the regulation of protein delivery in space and time. The translational regulation of gene expression enables a rapid response to stimuli or to a change in the environment, since the use of pre-existing mRNAs can bypass time-consuming nuclear control mechanisms. In the brain, the translation of distally localized mRNAs has been mainly studied in neurons, whose cytoplasmic protrusions may be more than 1000 times longer than the diameter of the cell body. Importantly, alterations in local translation in neurons have been implicated in several neurological diseases. Astrocytes, the most abundant glial cells in the brain, are voluminous, highly ramified cells that project long processes to neurons and brain vessels, and dynamically regulate distal synaptic and vascular functions. Recent research has demonstrated the presence of local translation at these astrocytic interfaces that might regulate the functional compartmentalization of astrocytes. In this Review, we summarize our current knowledge about the localization and local translation of mRNAs in the distal perisynaptic and perivascular processes of astrocytes, and discuss their possible contribution to the molecular and functional polarity of astrocytes.
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Affiliation(s)
- Noémie Mazaré
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, F-75005 Paris, France.,École doctorale Cerveau Cognition Comportement 'ED3C' No. 158, Pierre and Marie Curie University, F-75005 Paris, France
| | - Marc Oudart
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, F-75005 Paris, France.,École doctorale Cerveau Cognition Comportement 'ED3C' No. 158, Pierre and Marie Curie University, F-75005 Paris, France
| | - Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, F-75005 Paris, France .,École doctorale Cerveau Cognition Comportement 'ED3C' No. 158, Pierre and Marie Curie University, F-75005 Paris, France
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14
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Brayman VL, Taetzsch T, Miko M, Dahal S, Risher WC, Valdez G. Roles of the synaptic molecules Hevin and SPARC in mouse neuromuscular junction development and repair. Neurosci Lett 2021; 746:135663. [PMID: 33493647 DOI: 10.1016/j.neulet.2021.135663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 01/07/2023]
Abstract
Hevin and secreted protein acidic and rich in cysteine (SPARC) are highly homologous matricellular proteins that function in concert to guide the formation of brain synapses. Here, we investigated the role of these glycoproteins in neuromuscular junction (NMJ) maturation, stability, and repair following injury. Hevin and SPARC mRNA levels in developing (postnatal day 9), adult (postnatal days 90 and 120), and injured (fibular nerve crush) skeletal muscles were assessed with qPCR. Muscle fiber size was analyzed in developing (P9) mice lacking SPARC, Hevin, and both SPARC and Hevin. NMJ morphology was assessed in developing (P9), adult (P90) and injured (fibular nerve crush) mice lacking SPARC, Hevin, and both SPARC and Hevin skeletal muscle. Hevin and SPARC are expressed in skeletal muscles and are upregulated following nerve injury. Hevin-/- mice exhibited delayed NMJ and muscle fiber development but displayed normal NMJ morphology in adulthood and accelerated NMJ reinnervation following nerve injury. Mice lacking SPARC displayed normal NMJ and muscle fiber development but exhibited smaller NMJs with fewer acetylcholine receptor islands in adulthood. Further, SPARC deletion did not result in overt changes in NMJ reformation following nerve injury. The combined deletion of Hevin and SPARC had little effect on NMJ phenotypes observed in single knockouts, however deletion of SPARC in combination with Hevin reversed deficiencies in muscle fiber maturation observed in Hevin-/- muscle. These results identify SPARC and Hevin as extracellular matrix proteins with roles in NMJ development and repair.
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Affiliation(s)
- Vanessa L Brayman
- Fralin Biomedical Research Institute, Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA, 24016, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, 1 Riverside Circle, Roanoke, VA, 24016, USA
| | - Thomas Taetzsch
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - MacKenzie Miko
- Fralin Biomedical Research Institute, Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - Shreyaska Dahal
- Fralin Biomedical Research Institute, Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - W Christopher Risher
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine at Marshall University, 1 John Marshall Drive, Huntington, WV, 25755, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA; Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, United States; Department of Neurology, Warren Alpert Medical School of Brown University, Providence, United States.
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15
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Abstract
Astrocytes are the most abundant glial cells in the mammalian brain and directly participate in the proper functioning of the nervous system by regulating ion homeostasis, controlling glutamate reuptake, and maintaining the blood-brain barrier. In the last two decades, a growing body of work also identified critical roles for astrocytes in regulating synaptic connectivity. Stemming from the observation that functional and morphological development of astrocytes occur concurrently with synapse formation and maturation, these studies revealed that both developmental processes are directly linked. In fact, astrocytes both physically contact numerous synaptic structures and actively instruct many aspects of synaptic development and function via a plethora of secreted and adhesion-based molecular signals. The complex astrocyte-to-neuron signaling modalities control different stages of synaptic development such as regulating the initial formation of structural synapses as well as their functional maturation. Furthermore, the synapse-modulating functions of astrocytes are evolutionarily conserved and contribute to the development and plasticity of diverse classes of synapses and circuits throughout the central nervous system. Importantly, because impaired synapse formation and function is a hallmark of many neurodevelopmental disorders, deficits in astrocytes are likely to be major contributors to disease pathogenesis. In this chapter, we review our current understanding of the cellular and molecular mechanisms by which astrocytes contribute to synapse development and discuss the bidirectional secretion-based and contact-mediated mechanisms responsible for these essential developmental processes.
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Affiliation(s)
- Christabel X Tan
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - Caley J Burrus Lane
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC, United States
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC, United States; Duke Institute for Brain Sciences, Durham, NC, United States; Regeneration Next Initiative, Duke University, Durham, NC, United States.
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16
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Perez-Catalan NA, Doe CQ, Ackerman SD. The role of astrocyte-mediated plasticity in neural circuit development and function. Neural Dev 2021; 16:1. [PMID: 33413602 PMCID: PMC7789420 DOI: 10.1186/s13064-020-00151-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/26/2020] [Indexed: 02/03/2023] Open
Abstract
Neuronal networks are capable of undergoing rapid structural and functional changes called plasticity, which are essential for shaping circuit function during nervous system development. These changes range from short-term modifications on the order of milliseconds, to long-term rearrangement of neural architecture that could last for the lifetime of the organism. Neural plasticity is most prominent during development, yet also plays a critical role during memory formation, behavior, and disease. Therefore, it is essential to define and characterize the mechanisms underlying the onset, duration, and form of plasticity. Astrocytes, the most numerous glial cell type in the human nervous system, are integral elements of synapses and are components of a glial network that can coordinate neural activity at a circuit-wide level. Moreover, their arrival to the CNS during late embryogenesis correlates to the onset of sensory-evoked activity, making them an interesting target for circuit plasticity studies. Technological advancements in the last decade have uncovered astrocytes as prominent regulators of circuit assembly and function. Here, we provide a brief historical perspective on our understanding of astrocytes in the nervous system, and review the latest advances on the role of astroglia in regulating circuit plasticity and function during nervous system development and homeostasis.
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Affiliation(s)
- Nelson A Perez-Catalan
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR, USA
- Kennedy Center, Department of Pediatrics, The University of Chicago, Chicago, IL, USA
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR, USA
| | - Sarah D Ackerman
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR, USA.
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17
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Fossati G, Matteoli M, Menna E. Astrocytic Factors Controlling Synaptogenesis: A Team Play. Cells 2020; 9:E2173. [PMID: 32993090 PMCID: PMC7600026 DOI: 10.3390/cells9102173] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022] Open
Abstract
Astrocytes are essential players in brain circuit development and homeostasis, controlling many aspects of synapse formation, function, plasticity and elimination both during development and adulthood. Accordingly, alterations in astrocyte morphogenesis and physiology may severely affect proper brain development, causing neurological or neuropsychiatric conditions. Recent findings revealed a huge astrocyte heterogeneity among different brain areas, which is likely at the foundation of the different synaptogenic potential of these cells in selected brain regions. This review highlights recent findings on novel mechanisms that regulate astrocyte-mediated synaptogenesis during development, and the control of synapse number in the critical period or upon synaptic plasticity.
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Affiliation(s)
- Giuliana Fossati
- Humanitas Clinical and Research Center—IRCCS—NeuroCenter, via Manzoni 56, 20089 Rozzano, Milan, Italy; (G.F.); (M.M.)
| | - Michela Matteoli
- Humanitas Clinical and Research Center—IRCCS—NeuroCenter, via Manzoni 56, 20089 Rozzano, Milan, Italy; (G.F.); (M.M.)
- CNR, Department of Biomedical Sciences, Institute of Neuroscience—URT Humanitas, via Manzoni 56, 20089 Rozzano, Italy
| | - Elisabetta Menna
- Humanitas Clinical and Research Center—IRCCS—NeuroCenter, via Manzoni 56, 20089 Rozzano, Milan, Italy; (G.F.); (M.M.)
- CNR, Department of Biomedical Sciences, Institute of Neuroscience—URT Humanitas, via Manzoni 56, 20089 Rozzano, Italy
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18
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Synapse elimination activates a coordinated homeostatic presynaptic response in an autaptic circuit. Commun Biol 2020; 3:260. [PMID: 32444808 PMCID: PMC7244710 DOI: 10.1038/s42003-020-0963-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/21/2020] [Indexed: 01/27/2023] Open
Abstract
The number of synapses present in a neuronal circuit is not fixed. Neurons must compensate for changes in connectivity caused by synaptic pruning, learning processes or pathological conditions through the constant adjustment of the baseline level of neurotransmission. Here, we show that cholinergic neurons grown in an autaptic circuit in the absence of glia sense the loss of half of their synaptic contacts triggered by exposure to peptide p4.2, a C-terminal fragment of SPARC. Synaptic elimination is driven by a reorganization of the periodic F-actin cytoskeleton present along neurites, and occurs without altering the density of postsynaptic receptors. Neurons recover baseline neurotransmission through a homeostatic presynaptic response that consists of the coordinated activation of rapid synapse formation and an overall potentiation of presynaptic calcium influx. These results demonstrate that neurons establishing autaptic connections continuously sense and adjust their synaptic output by tweaking the number of functional contacts and neurotransmitter release probability. Cecilia Velasco and Artur Llobet study how autapses respond to synapse elimination. They employ microisland cultures free of glial cells, treat with a SPARC-derived peptide and show that neurons forming autaptic circuits continuously sense and regulate the number of contacts and neurotransmitter release.
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19
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Duncan S, Delage S, Chioran A, Sirbu O, Brown TJ, Ringuette MJ. The predicted collagen-binding domains of Drosophila SPARC are essential for survival and for collagen IV distribution and assembly into basement membranes. Dev Biol 2020; 461:197-209. [PMID: 32087195 DOI: 10.1016/j.ydbio.2020.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 01/29/2020] [Accepted: 02/15/2020] [Indexed: 11/17/2022]
Abstract
The assembly of basement membranes (BMs) into tissue-specific morphoregulatory structures requires non-core BM components. Work in Drosophila indicates a principal role of collagen-binding matricellular glycoprotein SPARC (Secreted Protein, Acidic, Rich in Cysteine) in larval fat body BM assembly. We report that SPARC and collagen IV (Col(IV)) first colocalize in the trans-Golgi of hemocyte-like cell lines. Mutating the collagen-binding domains of Drosophila SPARC led to the loss of colocalization with Col(IV), a fibrotic-like BM, and 2nd instar larval lethality, indicating that SPARC binding to Col(IV) is essential for survival. Analysis of this mutant at 2nd instar reveals increased Col(IV) puncta within adipocytes, reflecting a disruption in the intracellular chaperone-like activity of SPARC. Removal of the disulfide bridge in the C-terminal EF-hand2 of SPARC, which is known to enhance Col(IV) binding, did not lead to larval lethality; however, a less intense fat body phenotype was observed. Additionally, both SPARC mutants exhibited altered fat body BM pore topography. Wing imaginal disc-derived SPARC did not localize within Col(IV)-rich matrices. This raises the possibility that SPARC interaction with Col(IV) requires initial intracellular interaction to colocalize at the BM or that wing-derived SPARC undergoes differential post-translational modifications that impacts its function. Collectively, these data provide evidence that the chaperone-like activity of SPARC on Col(IV) begins just prior to their co-secretion and demonstrate for the first time that the Col(IV) chaperone-like activity of SPARC is necessary for Drosophila development beyond the 2nd instar.
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Affiliation(s)
- Sebastian Duncan
- Department of Cells and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Samuel Delage
- Department of Cells and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Alexa Chioran
- Department of Cells and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Olga Sirbu
- Department of Cells and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Theodore J Brown
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Ontario, Canada; Lunenfeld-Tanenbaum, Research Institute at Sinai Health Systems, Toronto, Ontario, Canada
| | - Maurice J Ringuette
- Department of Cells and Systems Biology, University of Toronto, Toronto, Ontario, Canada.
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20
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Martínez San Segundo P, Terni B, Burgueño J, Monroy X, Dordal A, Merlos M, Llobet A. Outside-in regulation of the readily releasable pool of synaptic vesicles by α2δ-1. FASEB J 2019; 34:1362-1377. [PMID: 31914622 DOI: 10.1096/fj.201901551r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/09/2019] [Accepted: 10/23/2019] [Indexed: 12/17/2022]
Abstract
The readily releasable pool (RRP) of synaptic vesicles is a key determinant of phasic neurotransmission. Although the size of the RRP is tightly regulated by intracellular factors, there is little evidence for its modification by extracellular signals. By studying the homogeneous population of synapses present in autaptic microcultures, we show that pregabalin, a prototypical gabapentinoid, decreases the effective RRP size. Simultaneous imaging of presynaptic calcium influx and recording of postsynaptic responses shows that the effect is not related to a reduction of calcium entry. The main cause is the impairment of the functional coupling among N-type calcium channels and the RRP, resembling an increase of intracellular mobile calcium buffers. The ectodomain of neurexin-1α shows a similar action to pregabalin, acting as an endogenous ligand of α2δ-1 that reduces the RRP size without affecting presynaptic calcium influx. The regulatory actions described for pregabalin and the ectodomain of neurexin-1α are mutually exclusive. The overexpression of α2δ-1 enhances the effect of pregabalin and the ectodomain of neurexin-1α on neurotransmission by decreasing their effective concentration. In contrast, knockdown of α2δ-1 causes a profound inhibition of synaptic transmission. These observations prompt to consider α2δ-1 as an outside-in signaling platform that binds exogenous and endogenous cues for regulating the coupling of voltage-gated calcium channels to synaptic vesicles.
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Affiliation(s)
- Pablo Martínez San Segundo
- Laboratory of Neurobiology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Department of Pathology and Experimental Therapeutics, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Beatrice Terni
- Laboratory of Neurobiology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Department of Pathology and Experimental Therapeutics, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Javier Burgueño
- Department of Pharmacology, Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | - Xavier Monroy
- Department of Pharmacology, Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | - Albert Dordal
- Department of Pharmacology, Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | - Manuel Merlos
- Department of Pharmacology, Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Department of Pathology and Experimental Therapeutics, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
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21
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Dallérac G, Zapata J, Rouach N. Versatile control of synaptic circuits by astrocytes: where, when and how? Nat Rev Neurosci 2019; 19:729-743. [PMID: 30401802 DOI: 10.1038/s41583-018-0080-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Close structural and functional interactions of astrocytes with synapses play an important role in brain function. The repertoire of ways in which astrocytes can regulate synaptic transmission is complex so that they can both promote and dampen synaptic efficacy. Such contrasting effects raise questions regarding the determinants of these divergent astroglial functions. Recent findings provide insights into where, when and how astroglial regulation of synapses takes place by revealing major molecular and functional intrinsic heterogeneity as well as switches in astrocytes occurring during development or specific patterns of neuronal activity. Astrocytes may therefore be seen as boosters or gatekeepers of synaptic circuits depending on their intrinsic and transformative properties throughout life.
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Affiliation(s)
- Glenn Dallérac
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Jonathan Zapata
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.
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22
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Erickson EK, Blednov YA, Harris RA, Mayfield RD. Glial gene networks associated with alcohol dependence. Sci Rep 2019; 9:10949. [PMID: 31358844 PMCID: PMC6662804 DOI: 10.1038/s41598-019-47454-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/17/2019] [Indexed: 02/07/2023] Open
Abstract
Chronic alcohol abuse alters the molecular structure and function of brain cells. Recent work suggests adaptations made by glial cells, such as astrocytes and microglia, regulate physiological and behavioral changes associated with addiction. Defining how alcohol dependence alters the transcriptome of different cell types is critical for developing the mechanistic hypotheses necessary for a nuanced understanding of cellular signaling in the alcohol-dependent brain. We performed RNA-sequencing on total homogenate and glial cell populations isolated from mouse prefrontal cortex (PFC) following chronic intermittent ethanol vapor exposure (CIE). Compared with total homogenate, we observed unique and robust gene expression changes in astrocytes and microglia in response to CIE. Gene co-expression network analysis revealed biological pathways and hub genes associated with CIE in astrocytes and microglia that may regulate alcohol-dependent phenotypes. Astrocyte identity and synaptic calcium signaling genes were enriched in alcohol-associated astrocyte networks, while TGF-β signaling and inflammatory response genes were disrupted by CIE treatment in microglia gene networks. Genes related to innate immune signaling, specifically interferon pathways, were consistently up-regulated across CIE-exposed astrocytes, microglia, and total homogenate PFC tissue. This study illuminates the cell-specific effects of chronic alcohol exposure and provides novel molecular targets for studying alcohol dependence.
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Affiliation(s)
- Emma K Erickson
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA.
| | - Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA
| | - R Dayne Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712-01095, USA
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23
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Abstract
Maturation of neuronal circuits requires selective elimination of synaptic connections. Although neuron-intrinsic mechanisms are important in this process, it is increasingly recognized that glial cells also play a critical role. Without proper functioning of these cells, the number, morphology, and function of synaptic contacts are profoundly altered, resulting in abnormal connectivity and behavioral abnormalities. In addition to their role in synaptic refinement, glial cells have also been implicated in pathological synapse loss and dysfunction following injury or nervous system degeneration in adults. Although mechanisms regulating glia-mediated synaptic elimination are still being uncovered, it is clear this complex process involves many cues that promote and inhibit the removal of specific synaptic connections. Gaining a greater understanding of these signals and the contribution of different cell types will not only provide insight into this critical biological event but also be instrumental in advancing knowledge of brain development and neural disease.
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Affiliation(s)
- Daniel K. Wilton
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Lasse Dissing-Olesen
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Beth Stevens
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center, Broad Institute, Cambridge, Massachusetts 02142, USA
- Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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24
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Interaction of Nerve Growth Factor β with Adiponectin and SPARC Oppositely Modulates its Biological Activity. Int J Mol Sci 2019; 20:ijms20071541. [PMID: 30934765 PMCID: PMC6479836 DOI: 10.3390/ijms20071541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 12/31/2022] Open
Abstract
Both adiponectin and secreted protein, acidic and rich in cysteine (SPARC) inhibit platelet-derived growth factor-BB (PDGF-BB)-induced and basic fibroblast growth factor (FGF2)-induced angiogenic activities through direct and indirect interactions. Although SPARC enhances nerve growth factor (NGF)-dependent neurogenesis, the physical interaction of NGFβ with adiponectin and SPARC remains obscure. Therefore, we first examined their intermolecular interaction by surface plasmon resonance method. NGFβ bound to immobilized SPARC with the binding constant of 59.4 nM, comparable with that of PDGF-BB (24.5 nM) but far less than that of FGF2 (14.4 µM). NGFβ bound to immobilized full length adiponectin with the binding constant of 103 nM, slightly higher than those of PDGF-BB (24.3 nM) and FGF2 (80.2 nM), respectively. Treatment of PC12 cells with SPARC did not cause mitogen-activated protein kinase (MAPK) activation and neurite outgrowth. However, simultaneous addition of SPARC with NGFβ enhanced NGFβ-induced MAPK phosphorylation and neurite outgrowth. Treatment of the cells with adiponectin increased AMP-activated protein kinase (AMPK) phosphorylation but failed to induce neurite outgrowth. Simultaneous treatment with NGFβ and adiponectin significantly reduced cell size and the number of cells with neurite, even after silencing the adiponectin receptors by their siRNA. These results indicate that NGFβ directly interacts with adiponectin and SPARC, whereas these interactions oppositely regulate NGFβ functions.
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25
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Darville LNF, Sokolowski BHA. Label-free quantitative mass spectrometry analysis of differential protein expression in the developing cochlear sensory epithelium. Proteome Sci 2018; 16:15. [PMID: 30127667 PMCID: PMC6091194 DOI: 10.1186/s12953-018-0144-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 07/26/2018] [Indexed: 12/27/2022] Open
Abstract
Background The sensory epithelium of the inner ear converts the mechanical energy of sound to electro-chemical energy recognized by the central nervous system. This process is mediated by receptor cells known as hair cells that express proteins in a timely fashion with the onset of hearing. Methods The proteomes of 3, 14, and 30 day-old mice cochlear sensory epithelia were revealed, using label-free quantitative mass spectrometry (LTQ-Orbitrap). Statistical analysis using a one-way ANOVA followed by Bonferroni’s post-hoc test was used to show significant differences in protein expression. Ingenuity Pathway Analysis was used to observe networks of differentially expressed proteins, their biological processes, and associated diseases, while Cytoscape software was used to determine putative interactions with select biomarker proteins. These candidate biomarkers were further verified using Western blotting, while coimmunoprecipitation was used to verify putative partners determined using bioinformatics. Results We show that a comparison across all three proteomes shows that there are 447 differentially expressed proteins, with 387 differentially expressed between postnatal day 3 and 30. Ingenuity Pathway Analysis revealed ~ 62% of postnatal day 3 downregulated proteins are involved in neurological diseases. Several proteins are expressed exclusively on P3, including Parvin α, Drebrin1 (Drb1), Secreted protein acidic and cysteine rich (SPARC), Transmembrane emp24 domain-containing protein 10 (Tmed10). Coimmunoprecipitations showed that Parvin and SPARC interact with integrin-linked protein kinase and the large conductance calcium-activated potassium channel, respectively. Conclusions Quantitative mass spectrometry revealed the identification of numerous differentially regulated proteins over three days of postnatal development. These data provide insights into functional pathways regulating normal sensory and supporting cell development in the cochlea that include potential biomarkers. Interacting partners of two of these markers suggest the importance of these complexes in regulating cellular structure and synapse development. Electronic supplementary material The online version of this article (10.1186/s12953-018-0144-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lancia N F Darville
- Morsani College of Medicine, Department of Otolaryngology-HNS, University of South Florida, 12901 Bruce B. Downs Blvd, Tampa, FL 33612 USA
| | - Bernd H A Sokolowski
- Morsani College of Medicine, Department of Otolaryngology-HNS, University of South Florida, 12901 Bruce B. Downs Blvd, Tampa, FL 33612 USA
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26
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Jung YJ, Chung WS. Phagocytic Roles of Glial Cells in Healthy and Diseased Brains. Biomol Ther (Seoul) 2018; 26:350-357. [PMID: 29316776 PMCID: PMC6029679 DOI: 10.4062/biomolther.2017.133] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/12/2017] [Accepted: 09/26/2017] [Indexed: 11/10/2022] Open
Abstract
Glial cells are receiving much attention since they have been recognized as important regulators of many aspects of brain function and disease. Recent evidence has revealed that two different glial cells, astrocytes and microglia, control synapse elimination under normal and pathological conditions via phagocytosis. Astrocytes use the MEGF10 and MERTK phagocytic pathways, and microglia use the classical complement pathway to recognize and eliminate unwanted synapses. Notably, glial phagocytosis also contributes to the clearance of disease-specific protein aggregates, such as β-amyloid, huntingtin, and α-synuclein. Here we reivew recent findings showing that glial cells are active regulators in brain functions through phagocytosis and that changes in glial phagocytosis contribute to the pathogenesis of various neurodegenerative diseases. A better understanding of the cellular and molecular mechanisms of glial phagocytosis in healthy and diseased brains will greatly improve our current approach in treating these diseases.
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Affiliation(s)
- Yeon-Joo Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Won-Suk Chung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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Sidlauskaite E, Gibson JW, Megson IL, Whitfield PD, Tovmasyan A, Batinic-Haberle I, Murphy MP, Moult PR, Cobley JN. Mitochondrial ROS cause motor deficits induced by synaptic inactivity: Implications for synapse pruning. Redox Biol 2018; 16:344-351. [PMID: 29587245 PMCID: PMC5953219 DOI: 10.1016/j.redox.2018.03.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/15/2018] [Accepted: 03/17/2018] [Indexed: 01/05/2023] Open
Abstract
Developmental synapse pruning refines burgeoning connectomes. The basic mechanisms of mitochondrial reactive oxygen species (ROS) production suggest they select inactive synapses for pruning: whether they do so is unknown. To begin to unravel whether mitochondrial ROS regulate pruning, we made the local consequences of neuromuscular junction (NMJ) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing Xenopus laevis tadpoles. We resolved whether: (1) synaptic inactivity increases mitochondrial ROS; and (2) chemically heterogeneous antioxidants rescue synaptic inactivity induced motor deficits. Regardless of whether it was achieved with muscle (α-bungarotoxin), nerve (α-latrotoxin) targeted neurotoxins or an endogenous pruning cue (SPARC), synaptic inactivity increased mitochondrial ROS in vivo. The manganese porphyrins MnTE-2-PyP5+ and/or MnTnBuOE-2-PyP5+ blocked mitochondrial ROS to significantly reduce neurotoxin and endogenous pruning cue induced motor deficits. Selectively inducing mitochondrial ROS-using mitochondria-targeted Paraquat (MitoPQ)-recapitulated synaptic inactivity induced motor deficits; which were significantly reduced by blocking mitochondrial ROS with MnTnBuOE-2-PyP5+. We unveil mitochondrial ROS as synaptic activity sentinels that regulate the phenotypical consequences of forced synaptic inactivity at the NMJ. Our novel results are relevant to pruning because synaptic inactivity is one of its defining features.
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Affiliation(s)
- Eva Sidlauskaite
- School of Science Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
| | - Jack W Gibson
- School of Science Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
| | - Ian L Megson
- Institute of Health Science, University of Highlands and Islands, Inverness IV2 3JH, UK
| | - Philip D Whitfield
- Institute of Health Science, University of Highlands and Islands, Inverness IV2 3JH, UK
| | - Artak Tovmasyan
- Department of Radiation Oncology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, CB2 0XY, UK
| | - Peter R Moult
- School of Science Engineering and Technology, Abertay University, Dundee DD1 1HG, UK
| | - James N Cobley
- Institute of Health Science, University of Highlands and Islands, Inverness IV2 3JH, UK.
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28
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Ferrer-Ferrer M, Dityatev A. Shaping Synapses by the Neural Extracellular Matrix. Front Neuroanat 2018; 12:40. [PMID: 29867379 PMCID: PMC5962695 DOI: 10.3389/fnana.2018.00040] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/25/2018] [Indexed: 11/13/2022] Open
Abstract
Accumulating data support the importance of interactions between pre- and postsynaptic neuronal elements with astroglial processes and extracellular matrix (ECM) for formation and plasticity of chemical synapses, and thus validate the concept of a tetrapartite synapse. Here we outline the major mechanisms driving: (i) synaptogenesis by secreted extracellular scaffolding molecules, like thrombospondins (TSPs), neuronal pentraxins (NPs) and cerebellins, which respectively promote presynaptic, postsynaptic differentiation or both; (ii) maturation of synapses via reelin and integrin ligands-mediated signaling; and (iii) regulation of synaptic plasticity by ECM-dependent control of induction and consolidation of new synaptic configurations. Particularly, we focused on potential importance of activity-dependent concerted activation of multiple extracellular proteases, such as ADAMTS4/5/15, MMP9 and neurotrypsin, for permissive and instructive events in synaptic remodeling through localized degradation of perisynaptic ECM and generation of proteolytic fragments as inducers of synaptic plasticity.
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Affiliation(s)
- Maura Ferrer-Ferrer
- Molecular Neuroplasticity German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.,Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
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29
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Abstract
The extracellular matrix (ECM) has central roles in tissue integrity and remodeling throughout the life span of animals. While collagens are the most abundant structural components of ECM in most tissues, tissue-specific molecular complexity is contributed by ECM glycoproteins. The matricellular glycoproteins are categorized primarily according to functional criteria and represented predominantly by the thrombospondin, tenascin, SPARC/osteonectin, and CCN families. These proteins do not self-assemble into ECM fibrils; nevertheless, they shape ECM properties through interactions with structural ECM proteins, growth factors, and cells. Matricellular proteins also promote cell migration or morphological changes through adhesion-modulating or counter-adhesive actions on cell-ECM adhesions, intracellular signaling, and the actin cytoskeleton. Typically, matricellular proteins are most highly expressed during embryonic development. In adult tissues, expression is more limited unless activated by cues for dynamic tissue remodeling and cell motility, such as occur during inflammatory response and wound repair. Many insights in the complex roles of matricellular proteins have been obtained from studies of gene knockout mice. However, with the exception of chordate-specific tenascins, these are highly conserved proteins that are encoded in many animal phyla. This review will consider the increasing body of research on matricellular proteins in nonmammalian animal models. These models provide better access to the very earliest stages of embryonic development and opportunities to study biological processes such as limb and organ regeneration. In aggregate, this research is expanding concepts of the functions and mechanisms of action of matricellular proteins.
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Affiliation(s)
- Josephine C Adams
- School of Biochemistry, University of Bristol, Bristol, United Kingdom.
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30
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Hillen AEJ, Burbach JPH, Hol EM. Cell adhesion and matricellular support by astrocytes of the tripartite synapse. Prog Neurobiol 2018; 165-167:66-86. [PMID: 29444459 DOI: 10.1016/j.pneurobio.2018.02.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/25/2017] [Accepted: 02/07/2018] [Indexed: 12/18/2022]
Abstract
Astrocytes contribute to the formation, function, and plasticity of synapses. Their processes enwrap the neuronal components of the tripartite synapse, and due to this close interaction they are perfectly positioned to modulate neuronal communication. The interaction between astrocytes and synapses is facilitated by cell adhesion molecules and matricellular proteins, which have been implicated in the formation and functioning of tripartite synapses. The importance of such neuron-astrocyte integration at the synapse is underscored by the emerging role of astrocyte dysfunction in synaptic pathologies such as autism and schizophrenia. Here we review astrocyte-expressed cell adhesion molecules and matricellular molecules that play a role in integration of neurons and astrocytes within the tripartite synapse.
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Affiliation(s)
- Anne E J Hillen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Department of Pediatrics/Child Neurology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - J Peter H Burbach
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands; Department of Neuroimmunology, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands.
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31
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Single-cell transcriptomics of the developing lateral geniculate nucleus reveals insights into circuit assembly and refinement. Proc Natl Acad Sci U S A 2018; 115:E1051-E1060. [PMID: 29343640 PMCID: PMC5798372 DOI: 10.1073/pnas.1717871115] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Neurons and nonneuronal cells in the developing brain dynamically regulate gene expression as neural connectivity is established. However, the specific gene programs activated in distinct cell populations during the assembly and refinement of many intact neuronal circuits have not been thoroughly characterized. In this study, we take advantage of recent advances in transcriptomic profiling techniques to characterize gene expression in the postnatal developing lateral geniculate nucleus (LGN) at single-cell resolution. Our data reveal that genes involved in brain development are dynamically regulated in all major cell types of the LGN, suggesting that the establishment of neural connectivity depends upon functional collaboration between multiple neuronal and nonneuronal cell types in this brain region. Coordinated changes in gene expression underlie the early patterning and cell-type specification of the central nervous system. However, much less is known about how such changes contribute to later stages of circuit assembly and refinement. In this study, we employ single-cell RNA sequencing to develop a detailed, whole-transcriptome resource of gene expression across four time points in the developing dorsal lateral geniculate nucleus (LGN), a visual structure in the brain that undergoes a well-characterized program of postnatal circuit development. This approach identifies markers defining the major LGN cell types, including excitatory relay neurons, oligodendrocytes, astrocytes, microglia, and endothelial cells. Most cell types exhibit significant transcriptional changes across development, dynamically expressing genes involved in distinct processes including retinotopic mapping, synaptogenesis, myelination, and synaptic refinement. Our data suggest that genes associated with synapse and circuit development are expressed in a larger proportion of nonneuronal cell types than previously appreciated. Furthermore, we used this single-cell expression atlas to identify the Prkcd-Cre mouse line as a tool for selective manipulation of relay neurons during a late stage of sensory-driven synaptic refinement. This transcriptomic resource provides a cellular map of gene expression across several cell types of the LGN, and offers insight into the molecular mechanisms of circuit development in the postnatal brain.
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32
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Cell Biology of Astrocyte-Synapse Interactions. Neuron 2017; 96:697-708. [PMID: 29096081 DOI: 10.1016/j.neuron.2017.09.056] [Citation(s) in RCA: 575] [Impact Index Per Article: 82.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 09/24/2017] [Accepted: 09/28/2017] [Indexed: 12/25/2022]
Abstract
Astrocytes, the most abundant glial cells in the mammalian brain, are critical regulators of brain development and physiology through dynamic and often bidirectional interactions with neuronal synapses. Despite the clear importance of astrocytes for the establishment and maintenance of proper synaptic connectivity, our understanding of their role in brain function is still in its infancy. We propose that this is at least in part due to large gaps in our knowledge of the cell biology of astrocytes and the mechanisms they use to interact with synapses. In this review, we summarize some of the seminal findings that yield important insight into the cellular and molecular basis of astrocyte-neuron communication, focusing on the role of astrocytes in the development and remodeling of synapses. Furthermore, we pose some pressing questions that need to be addressed to advance our mechanistic understanding of the role of astrocytes in regulating synaptic development.
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33
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Bosworth AP, Allen NJ. The diverse actions of astrocytes during synaptic development. Curr Opin Neurobiol 2017; 47:38-43. [PMID: 28938161 DOI: 10.1016/j.conb.2017.08.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/31/2017] [Indexed: 02/07/2023]
Abstract
In the developing brain, cortical circuits are established through a complex process of synaptogenesis, maturation, and synaptic pruning. Astrocytes carry out diverse functions during each of these stages to facilitate the formation of complex networks. Recent work has begun to demonstrate that these heterogeneous roles during excitatory synaptic development are determined by the astrocyte population, brain region, and neuron type. This review will focus on current findings which highlight cell type specific mechanisms of excitatory synaptogenesis, as well as multiple mechanisms engaged by astrocytes to facilitate synaptic maturation and pruning.
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Affiliation(s)
- Alexandra P Bosworth
- Salk Institute for Biological Studies, Molecular Neuroscience Laboratory, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA; Neurosciences Graduate Program, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neuroscience Laboratory, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA.
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34
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Baldwin KT, Eroglu C. Molecular mechanisms of astrocyte-induced synaptogenesis. Curr Opin Neurobiol 2017; 45:113-120. [PMID: 28570864 PMCID: PMC5573249 DOI: 10.1016/j.conb.2017.05.006] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/10/2017] [Indexed: 12/20/2022]
Abstract
Astrocytes are morphologically complex cells that perform a wide variety of critical functions in the brain. As a structurally and functionally integrated component of the synapse, astrocytes secrete proteins, lipids, and small molecules that bind neuronal receptors to promote synaptogenesis and regulate synaptic connectivity. Additionally, astrocytes are key players in circuit formation, instructing the formation of synapses between distinct classes of neurons. This review highlights recent publications on the topic of astrocyte-mediated synaptogenesis, with a focus on the molecular mechanisms through which astrocytes orchestrate the formation of synaptic circuits.
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Affiliation(s)
- Katherine T Baldwin
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States.
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Duke Institute for Brain Sciences (DIBS), Durham, NC 27710, United States.
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35
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Su JR, Kuai JH, Li YQ. Smoc2 potentiates proliferation of hepatocellular carcinoma cells via promotion of cell cycle progression. World J Gastroenterol 2016; 22:10053-10063. [PMID: 28018113 PMCID: PMC5143752 DOI: 10.3748/wjg.v22.i45.10053] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/07/2016] [Accepted: 10/26/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To determine the influence of Smoc2 on hepatocellular carcinoma (HCC) cell proliferation and to find a possible new therapeutic target for preventing HCC progression. METHODS We detected expression of Smoc2 in HCC tissues and corresponding non-tumor liver (CNL) tissues using PCR, western blot, and immunohistochemistry methods. Subsequently, we down-regulated and up-regulated Smoc2 expression using siRNA and lentivirus transfection assay, respectively. Then, we identified the effect of Smoc2 on cell proliferation and cell cycle using CCK-8 and flow cytometry, respectively. The common cell growth signaling influenced by Smoc2 was detected by western blot assay. RESULTS The expression of Smoc2 was significantly higher in HCC tissues compared with CNL tissues. Overexpression of Smoc2 promoted HCC cell proliferation and cell cycle progression. Down-regulation of Smoc2 led to inhibition of cell proliferation and cell cycle progression. Smoc2 had positive effect on ERK and AKT signaling. CONCLUSION Smoc2 promotes the proliferation of HCC cells through accelerating cell cycle progression and might act as an anti-cancer therapeutic target in the future.
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36
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Terni B, López-Murcia FJ, Llobet A. Role of neuron-glia interactions in developmental synapse elimination. Brain Res Bull 2016; 129:74-81. [PMID: 27601093 DOI: 10.1016/j.brainresbull.2016.08.017] [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: 06/02/2016] [Revised: 08/19/2016] [Accepted: 08/31/2016] [Indexed: 11/16/2022]
Abstract
During the embryonic development of the nervous system there is a massive formation of synapses. However, the exuberant connectivity present after birth must be pruned during postnatal growth to optimize the function of neuronal circuits. Whilst glial cells play a fundamental role in the formation of early synaptic contacts, their contribution to developmental modifications of established synapses is not well understood. The present review aims to highlight the various roles of glia in the developmental refinement of embryonic synaptic connectivity. We summarize recent evidences linking secretory abilities of glial cells to the disassembly of synaptic contacts that are complementary of a well-established phagocytic role. Considering a theoretical framework, it is discussed how release of glial molecules could be relevant to the developmental refinement of synaptic connectivity. Finally, we propose a three-stage model of synapse elimination in which neurons and glia are functionally associated to timely eliminate synapses.
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Affiliation(s)
- Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Francisco José López-Murcia
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Institute of Neurosciences, University of Barcelona and Bellvitge Biomedical Research Institute (IDIBELL), 08907 L'Hospitalet de Llobregat, Barcelona, Spain.
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37
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Alkabie S, Basivireddy J, Zhou L, Roskams J, Rieckmann P, Quandt JA. SPARC expression by cerebral microvascular endothelial cells in vitro and its influence on blood-brain barrier properties. J Neuroinflammation 2016; 13:225. [PMID: 27581191 PMCID: PMC5007716 DOI: 10.1186/s12974-016-0657-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/12/2016] [Indexed: 11/16/2022] Open
Abstract
Background SPARC (secreted protein acidic and rich in cysteine) is a nonstructural, cell-matrix modulating protein involved in angiogenesis and endothelial barrier function, yet its potential role in cerebrovascular development, inflammation, and repair in the central nervous system (CNS) remains undetermined. Methods This study examines SPARC expression in cultured human cerebral microvascular endothelial cells (hCMEC/D3)—an in vitro model of the blood-brain barrier (BBB)—as they transition between proliferative and barrier phenotypes and encounter pro-inflammatory stimuli. SPARC protein levels were quantified by Western blotting and immunocytochemistry and messenger RNA (mRNA) by RT-PCR. Results Constitutive SPARC expression by proliferating hCMEC/D3s is reduced as cells mature and establish a confluent monolayer. SPARC expression positively correlated with the proliferation marker Ki-67 suggesting a role for SPARC in cerebrovascular development. The pro-inflammatory molecules tumor necrosis factor-α (TNF-α) and endotoxin lipopolysaccharide (LPS) increased SPARC expression in cerebral endothelia. Interferon gamma (IFN-γ) abrogated SPARC induction observed with TNF-α alone. Barrier function assays show recombinant human (rh)-SPARC increased paracellular permeability and decreased transendothelial electrical resistance (TEER). This was paralleled by reduced zonula occludens-1 (ZO-1) and occludin expression in hCMEC/D3s exposed to rh-SPARC (1–10 μg/ml) compared with cells in media containing a physiological dose of SPARC. Conclusions Together, these findings define a role for SPARC in influencing cerebral microvascular properties and function during development and inflammation at the BBB such that it may mediate processes of CNS inflammation and repair. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0657-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samir Alkabie
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jayasree Basivireddy
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Lixin Zhou
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Jane Roskams
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Peter Rieckmann
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC, Canada.,Sozialstiftung Bamberg, Klinikum am Bruderwald, Neurologische Klinik, Buger Str. 80, Bamberg, 96049, Germany
| | - Jacqueline A Quandt
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
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