51
|
Poppe L, Rué L, Timmers M, Lenaerts A, Storm A, Callaerts-Vegh Z, Courtand G, de Boer A, Smolders S, Van Damme P, Van Den Bosch L, D'Hooge R, De Strooper B, Robberecht W, Lemmens R. EphA4 loss improves social memory performance and alters dendritic spine morphology without changes in amyloid pathology in a mouse model of Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2019; 11:102. [PMID: 31831046 PMCID: PMC6909519 DOI: 10.1186/s13195-019-0554-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/08/2019] [Indexed: 12/24/2022]
Abstract
Background EphA4 is a receptor of the ephrin system regulating spine morphology and plasticity in the brain. These processes are pivotal in the pathophysiology of Alzheimer’s disease (AD), characterized by synapse dysfunction and loss, and the progressive loss of memory and other cognitive functions. Reduced EphA4 signaling has been shown to rescue beta-amyloid-induced dendritic spine loss and long-term potentiation (LTP) deficits in cultured hippocampal slices and primary hippocampal cultures. In this study, we investigated whether EphA4 ablation might preserve synapse function and ameliorate cognitive performance in the APPPS1 transgenic mouse model of AD. Methods A postnatal genetic ablation of EphA4 in the forebrain was established in the APPPS1 mouse model of AD, followed by a battery of cognitive tests at 9 months of age to investigate cognitive function upon EphA4 loss. A Golgi-Cox staining was used to explore alterations in dendritic spine density and morphology in the CA1 region of the hippocampus. Results Upon EphA4 loss in APPPS1 mice, we observed improved social memory in the preference for social novelty test without affecting other cognitive functions. Dendritic spine analysis revealed altered synapse morphology as characterized by increased dendritic spine length and head width. These modifications were independent of hippocampal plaque load and beta-amyloid peptide levels since these were similar in mice with normal versus reduced levels of EphA4. Conclusion Loss of EphA4 improved social memory in a mouse model of Alzheimer’s disease in association with alterations in spine morphology.
Collapse
Affiliation(s)
- Lindsay Poppe
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Laura Rué
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Mieke Timmers
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Annette Lenaerts
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Annet Storm
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Zsuzsanna Callaerts-Vegh
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leuven, Belgium.,mINT Animal Behavior Core Facility, Faculty of Psychology, KU Leuven, Leuven, Belgium
| | - Gilles Courtand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Unité Mixte de Recherche 5287, Centre National de la Recherche Scientifique, Université de Bordeaux, 33076, Bordeaux, France
| | - Antina de Boer
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Silke Smolders
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Philip Van Damme
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Rudi D'Hooge
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leuven, Belgium
| | - Bart De Strooper
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium.,UK Dementia Research Institute at University College London, London, UK
| | - Wim Robberecht
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium. .,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium. .,Department of Neurology, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium.
| |
Collapse
|
52
|
Li J, Ma N, Chen J, Yan D, Zhang Q, Shi J. EphA4 receptor regulates outwardly rectifying chloride channel in CA1 hippocampal neurons after ischemia-reperfusion. Neuroreport 2019; 30:980-984. [PMID: 31469726 PMCID: PMC6735946 DOI: 10.1097/wnr.0000000000001311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/17/2019] [Indexed: 12/18/2022]
Abstract
CA1 hippocampal neurons are sensitive to ischemia. The erythropoietin-producing hepatocellular carcinoma (Eph) receptors are a cell-cell contact signaling pathway for regulating neuron function and death. However, the mechanisms of EphA receptor in neuron death after ischemia remain unclear. In this study, we present evidence that outwardly rectifying chloride channels reside in CA1 hippocampal neurons. EphA4 receptor increased chloride channel currents. Moreover, the EphA4 receptor no longer had significant effects on enhanced channel currents following ischemia-reperfusion. Inhibition of EphA4 receptor with EphA4-Fc significantly decreased the channel currents after ischemia-reperfusion. These results suggest that the increased effect of the EphA4 receptor on the outwardly rectifying chloride channel activity in CA1 hippocampal neurons may provide better treatment for ischemic brain injury.
Collapse
Affiliation(s)
- Jianguo Li
- Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Na Ma
- Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Jing Chen
- Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Deping Yan
- Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Qian Zhang
- Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| | - Jinchao Shi
- Key Laboratory of Cellular Physiology, Ministry of Education, Department of Physiology, Shanxi Medical University, Taiyuan, China
| |
Collapse
|
53
|
Reducing EphA4 before disease onset does not affect survival in a mouse model of Amyotrophic Lateral Sclerosis. Sci Rep 2019; 9:14112. [PMID: 31575928 PMCID: PMC6773754 DOI: 10.1038/s41598-019-50615-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/16/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects motor neurons resulting in severe neurological symptoms. Previous findings of our lab suggested that the axonal guidance tyrosine-kinase receptor EphA4 is an ALS disease-modifying gene. Reduction of EphA4 from developmental stages onwards rescued a motor neuron phenotype in zebrafish, and heterozygous deletion before birth in the SOD1G93A mouse model of ALS resulted in improved survival. Here, we aimed to gain more insights in the cell-specific role of decreasing EphA4 expression in addition to timing and amount of EphA4 reduction. To evaluate the therapeutic potential of lowering EphA4 later in life, we ubiquitously reduced EphA4 levels to 50% in SOD1G93A mice at 60 days of age, which did not modify disease parameters. Even further lowering EphA4 levels ubiquitously or in neurons, did not improve disease onset or survival. These findings suggest that lowering EphA4 as target in ALS may suffer from a complex therapeutic time window. In addition, the complexity of the Eph-ephrin signalling system may also possibly limit the therapeutic potential of such an approach in ALS. We suggest here that a specific EphA4 knockdown in adulthood may have a limited therapeutic potential for ALS.
Collapse
|
54
|
Ephrin-A5 potentiates netrin-1 axon guidance by enhancing Neogenin availability. Sci Rep 2019; 9:12009. [PMID: 31427645 PMCID: PMC6700147 DOI: 10.1038/s41598-019-48519-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 08/07/2019] [Indexed: 01/22/2023] Open
Abstract
Axonal growth cones are guided by molecular cues in the extracellular environment. The mechanisms of combinatorial integration of guidance signals at the growth cone cell membrane are still being unravelled. Limb-innervating axons of vertebrate spinal lateral motor column (LMC) neurons are attracted to netrin-1 via its receptor, Neogenin, and are repelled from ephrin-A5 through its receptor EphA4. The presence of both cues elicits synergistic guidance of LMC axons, but the mechanism of this effect remains unknown. Using fluorescence immunohistochemistry, we show that ephrin-A5 increases LMC growth cone Neogenin protein levels and netrin-1 binding. This effect is enhanced by overexpressing EphA4 and is inhibited by blocking ephrin-A5-EphA4 binding. These effects have a functional consequence on LMC growth cone responses since bath addition of ephrin-A5 increases the responsiveness of LMC axons to netrin-1. Surprisingly, the overexpression of EphA4 lacking its cytoplasmic tail, also enhances Neogenin levels at the growth cone and potentiates LMC axon preference for growth on netrin-1. Since netrins and ephrins participate in a wide variety of biological processes, the enhancement of netrin-1 signalling by ephrins may have broad implications.
Collapse
|
55
|
CAMK2-Dependent Signaling in Neurons Is Essential for Survival. J Neurosci 2019; 39:5424-5439. [PMID: 31064859 DOI: 10.1523/jneurosci.1341-18.2019] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 01/09/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CAMK2) is a key player in synaptic plasticity and memory formation. Mutations in Camk2a or Camk2b cause intellectual disability in humans, and severe plasticity and learning deficits in mice, indicating unique functions for each isoform. However, considering the high homology between CAMK2A and CAMK2B, it is conceivable that for critical functions, one isoform compensates for the absence of the other, and that the full functional spectrum of neuronal CAMK2 remains to be revealed.Here we show that germline as well as adult deletion of both CAMK2 isoforms in male or female mice is lethal. Moreover, Ca2+-dependent activity as well as autonomous activity of CAMK2 is essential for survival. Loss of both CAMK2 isoforms abolished LTP, whereas synaptic transmission remained intact. The double-mutants showed no gross morphological changes of the brain, and in contrast to the long-considered role for CAMK2 in the structural organization of the postsynaptic density (PSD), deletion of both CAMK2 isoforms did not affect the biochemical composition of the PSD. Together, these results reveal an essential role for CAMK2 signaling in early postnatal development as well as the mature brain, and indicate that the full spectrum of CAMK2 requirements cannot be revealed in the single mutants because of partial overlapping functions of CAMK2A and CAMK2B.SIGNIFICANCE STATEMENT CAMK2A and CAMK2B have been studied for over 30 years for their role in neuronal functioning. However, most studies were performed using single knock-out mice. Because the two isoforms show high homology with respect to structure and function, it is likely that some redundancy exists between the two isoforms, meaning that for critical functions CAMK2B compensates for the absence of CAMK2A and vice versa, leaving these functions to uncover. In this study, we generated Camk2a/Camk2b double-mutant mice, and observed that loss of CAMK2, as well as the loss of Ca2+-dependent and Ca2+-independent activity of CAMK2 is lethal. These results indicate that despite 30 years of research the full spectrum of CAMK2 functioning in neurons remains to be unraveled.
Collapse
|
56
|
Romanos J, Benke D, Saab AS, Zeilhofer HU, Santello M. Differences in glutamate uptake between cortical regions impact neuronal NMDA receptor activation. Commun Biol 2019; 2:127. [PMID: 30963115 PMCID: PMC6451009 DOI: 10.1038/s42003-019-0367-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/05/2019] [Indexed: 01/06/2023] Open
Abstract
Removal of synaptically-released glutamate by astrocytes is necessary to spatially and temporally limit neuronal activation. Recent evidence suggests that astrocytes may have specialized functions in specific circuits, but the extent and significance of such specialization are unclear. By performing direct patch-clamp recordings and two-photon glutamate imaging, we report that in the somatosensory cortex, glutamate uptake by astrocytes is slower during sustained synaptic stimulation when compared to lower stimulation frequencies. Conversely, glutamate uptake capacity is increased in the frontal cortex during higher frequency synaptic stimulation, thereby limiting extracellular buildup of glutamate and NMDA receptor activation in layer 5 pyramidal neurons. This efficient glutamate clearance relies on Na+/K+-ATPase function and both GLT-1 and non-GLT-1 transporters. Thus, by enhancing their glutamate uptake capacity, astrocytes in the frontal cortex may prevent excessive neuronal excitation during intense synaptic activity. These results may explain why diseases associated with network hyperexcitability differentially affect individual brain areas.
Collapse
Affiliation(s)
- Jennifer Romanos
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
| | - Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
| | - Aiman S. Saab
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
- Institute of Pharmaceutical Sciences, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Mirko Santello
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
| |
Collapse
|
57
|
Astrocyte function from information processing to cognition and cognitive impairment. Nat Neurosci 2019; 22:154-166. [DOI: 10.1038/s41593-018-0325-8] [Citation(s) in RCA: 294] [Impact Index Per Article: 58.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 12/06/2018] [Indexed: 12/22/2022]
|
58
|
Abstract
In the mammalian brain, highly specialized astrocytes serve as neural stem cells (NSCs) that divide and give rise to new neurons, in a process called neurogenesis. During embryonic development NSCs generate almost all neurons of the brain. Soon after birth the neurogenic potential of NSCs is highly reduced, and neurogenesis occurs only in two specialized brain regions called the neurogenic niches. Niche cells are essential to stem cells as they provide structural and nutritional support, and control fundamental stem cell decisions. Astrocytes, major components of the adult neurogenic niches, are evolving as important regulators of neurogenesis, by controlling NSC proliferation, fate choice, and differentiation of the progeny. Therefore, astrocytes contribute to neurogenesis in two ways: as NSCs and as niche cells. This review highlights the role of astrocyte-like NSCs during development and adulthood, and summarizes how niche astrocytes control the process of adult neurogenesis.
Collapse
|
59
|
Spinal Cord Stimulation for Pain Treatment After Spinal Cord Injury. Neurosci Bull 2018; 35:527-539. [PMID: 30560438 DOI: 10.1007/s12264-018-0320-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 08/11/2018] [Indexed: 12/30/2022] Open
Abstract
In addition to restoration of bladder, bowel, and motor functions, alleviating the accompanying debilitating pain is equally important for improving the quality of life of patients with spinal cord injury (SCI). Currently, however, the treatment of chronic pain after SCI remains a largely unmet need. Electrical spinal cord stimulation (SCS) has been used to manage a variety of chronic pain conditions that are refractory to pharmacotherapy. Yet, its efficacy, benefit profiles, and mechanisms of action in SCI pain remain elusive, due to limited research, methodological weaknesses in previous clinical studies, and a lack of mechanistic exploration of SCS for SCI pain control. We aim to review recent studies and outline the therapeutic potential of different SCS paradigms for traumatic SCI pain. We begin with an overview of its manifestations, classification, potential underlying etiology, and current challenges for its treatment. The clinical evidence for using SCS in SCI pain is then reviewed. Finally, future perspectives of pre-clinical research and clinical study of SCS for SCI pain treatment are discussed.
Collapse
|
60
|
Chen Y, Fu AKY, Ip NY. Synaptic dysfunction in Alzheimer's disease: Mechanisms and therapeutic strategies. Pharmacol Ther 2018; 195:186-198. [PMID: 30439458 DOI: 10.1016/j.pharmthera.2018.11.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD), the most prevalent neurodegenerative disease in the elderly population, is characterized by progressive cognitive decline and pathological hallmarks of amyloid plaques and neurofibrillary tangles. However, its pathophysiological mechanisms are poorly understood, and diagnostic tools and interventions are limited. Here, we review recent research on the amyloid hypothesis and beta-amyloid-induced dysfunction of neuronal synapses through distinct cell surface receptors. We also review how tau protein leads to synaptotoxicity through pathological modification, localization, and propagation. Finally, we discuss experimental therapeutics for AD and propose potential applications of disease-modifying strategies targeting synaptic failure for improved treatment of AD.
Collapse
Affiliation(s)
- Yu Chen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, Guangdong, China.
| | - Amy K Y Fu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, Guangdong, China
| | - Nancy Y Ip
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen, Guangdong, China.
| |
Collapse
|
61
|
Wei HX, Yao PS, Chen PP, Guan JH, Zhuang JH, Zhu JB, Wu G, Yang JS. Neuronal EphA4 Regulates OGD/R-Induced Apoptosis by Promoting Alternative Activation of Microglia. Inflammation 2018; 42:572-585. [DOI: 10.1007/s10753-018-0914-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
62
|
Mansilla A, Jordán-Álvarez S, Santana E, Jarabo P, Casas-Tintó S, Ferrús A. Molecular mechanisms that change synapse number. J Neurogenet 2018; 32:155-170. [DOI: 10.1080/01677063.2018.1506781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
63
|
Schiweck J, Eickholt BJ, Murk K. Important Shapeshifter: Mechanisms Allowing Astrocytes to Respond to the Changing Nervous System During Development, Injury and Disease. Front Cell Neurosci 2018; 12:261. [PMID: 30186118 PMCID: PMC6111612 DOI: 10.3389/fncel.2018.00261] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/31/2018] [Indexed: 12/30/2022] Open
Abstract
Astrocytes are the most prevalent glial cells in the brain. Historically considered as “merely supporting” neurons, recent research has shown that astrocytes actively participate in a large variety of central nervous system (CNS) functions including synaptogenesis, neuronal transmission and synaptic plasticity. During disease and injury, astrocytes efficiently protect neurons by various means, notably by sealing them off from neurotoxic factors and repairing the blood-brain barrier. Their ramified morphology allows them to perform diverse tasks by interacting with synapses, blood vessels and other glial cells. In this review article, we provide an overview of how astrocytes acquire their complex morphology during development. We then move from the developing to the mature brain, and review current research on perisynaptic astrocytic processes, with a particular focus on how astrocytes engage synapses and modulate their formation and activity. Comprehensive changes have been reported in astrocyte cell shape in many CNS pathologies. Factors influencing these morphological changes are summarized in the context of brain pathologies, such as traumatic injury and degenerative conditions. We provide insight into the molecular, cellular and cytoskeletal machinery behind these shape changes which drive the dynamic remodeling in astrocyte morphology during injury and the development of pathologies.
Collapse
Affiliation(s)
- Juliane Schiweck
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Britta J Eickholt
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kai Murk
- Institute for Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
64
|
Besnier M, Gasparino S, Vono R, Sangalli E, Facoetti A, Bollati V, Cantone L, Zaccagnini G, Maimone B, Fuschi P, Da Silva D, Schiavulli M, Aday S, Caputo M, Madeddu P, Emanueli C, Martelli F, Spinetti G. miR-210 Enhances the Therapeutic Potential of Bone-Marrow-Derived Circulating Proangiogenic Cells in the Setting of Limb Ischemia. Mol Ther 2018; 26:1694-1705. [PMID: 29908843 DOI: 10.1016/j.ymthe.2018.06.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 06/05/2018] [Accepted: 06/05/2018] [Indexed: 12/28/2022] Open
Abstract
Therapies based on circulating proangiogenic cells (PACs) have shown promise in ischemic disease models but require further optimization to reach the bedside. Ischemia-associated hypoxia robustly increases microRNA-210 (miR-210) expression in several cell types, including endothelial cells (ECs). In ECs, miR-210 represses EphrinA3 (EFNA3), inducing proangiogenic responses. This study provides new mechanistic evidences for a role of miR-210 in PACs. PACs were obtained from either adult peripheral blood or cord blood. miR-210 expression was modulated with either an inhibitory complementary oligonucleotide (anti-miR-210) or a miRNA mimic (pre-miR-210). Scramble and absence of transfection served as controls. As expected, hypoxia increased miR-210 in PACs. In vivo, migration toward and adhesion to the ischemic endothelium facilitate the proangiogenic actions of transplanted PACs. In vitro, PAC migration toward SDF-1α/CXCL12 was impaired by anti-miR-210 and enhanced by pre-miR-210. Moreover, pre-miR-210 increased PAC adhesion to ECs and supported angiogenic responses in co-cultured ECs. These responses were not associated with changes in extracellular miR-210 and were abrogated by lentivirus-mediated EFNA3 overexpression. Finally, ex-vivo pre-miR-210 transfection predisposed PACs to induce post-ischemic therapeutic neovascularization and blood flow recovery in an immunodeficient mouse limb ischemia model. In conclusion, miR-210 modulates PAC functions and improves their therapeutic potential in limb ischemia.
Collapse
Affiliation(s)
- Marie Besnier
- Bristol Heart Institute, School of Clinical Science, University of Bristol, Bristol, UK
| | - Stefano Gasparino
- Laboratory of Cardiovascular Research, IRCCS MultiMedica, Milan, Italy
| | - Rosa Vono
- Laboratory of Cardiovascular Research, IRCCS MultiMedica, Milan, Italy
| | - Elena Sangalli
- Laboratory of Cardiovascular Research, IRCCS MultiMedica, Milan, Italy
| | - Amanda Facoetti
- Laboratory of Cardiovascular Research, IRCCS MultiMedica, Milan, Italy
| | - Valentina Bollati
- EPIGET Lab, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Laura Cantone
- EPIGET Lab, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Germana Zaccagnini
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, San Donato, Italy
| | - Biagina Maimone
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, San Donato, Italy
| | - Paola Fuschi
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, San Donato, Italy
| | - Daniel Da Silva
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, San Donato, Italy
| | - Michele Schiavulli
- AORN Santobono Pausilipon, Transfusion Medicine and Bone Marrow Transplantation Unit-Regional Reference Center for Coagulation Disorders, Napoli, Italy
| | - Sezin Aday
- Bristol Heart Institute, School of Clinical Science, University of Bristol, Bristol, UK
| | - Massimo Caputo
- Bristol Heart Institute, School of Clinical Science, University of Bristol, Bristol, UK
| | - Paolo Madeddu
- Bristol Heart Institute, School of Clinical Science, University of Bristol, Bristol, UK
| | - Costanza Emanueli
- Bristol Heart Institute, School of Clinical Science, University of Bristol, Bristol, UK; National Heart and Lung Institute, Imperial College London, London, UK
| | - Fabio Martelli
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, San Donato, Italy.
| | - Gaia Spinetti
- Laboratory of Cardiovascular Research, IRCCS MultiMedica, Milan, Italy.
| |
Collapse
|
65
|
Faw TD, Lerch JK, Thaxton TT, Deibert RJ, Fisher LC, Basso DM. Unique Sensory and Motor Behavior in Thy1-GFP-M Mice before and after Spinal Cord Injury. J Neurotrauma 2018; 35:2167-2182. [PMID: 29385890 DOI: 10.1089/neu.2017.5395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sensorimotor recovery after spinal cord injury (SCI) is of utmost importance to injured individuals and will rely on improved understanding of SCI pathology and recovery. Novel transgenic mouse lines facilitate discovery, but must be understood to be effective. The purpose of this study was to characterize the sensory and motor behavior of a common transgenic mouse line (Thy1-GFP-M) before and after SCI. Thy1-GFP-M positive (TG+) mice and their transgene negative littermates (TG-) were acquired from two sources (in-house colony, n = 32, Jackson Laboratories, n = 4). C57BL/6J wild-type (WT) mice (Jackson Laboratories, n = 10) were strain controls. Moderate-severe T9 contusion (SCI) or transection (TX) occurred in TG+ (SCI, n = 25, TX, n = 5), TG- (SCI, n = 5), and WT (SCI, n = 10) mice. To determine responsiveness to rehabilitation, a cohort of TG+ mice with SCI (n = 4) had flat treadmill (TM) training 42-49 days post-injury (dpi). To characterize recovery, we performed Basso Mouse Scale, Grid Walk, von Frey Hair, and Plantar Heat Testing before and out to day 42 post-SCI. Open field locomotion was significantly better in the Thy1 SCI groups (TG+ and TG-) compared with WT by 7 dpi (p < 0.01) and was maintained through 42 dpi (p < 0.01). These unexpected locomotor gains were not apparent during grid walking, indicating severe impairment of precise motor control. Thy1 derived mice were hypersensitive to mechanical stimuli at baseline (p < 0.05). After SCI, mechanical hyposensitivity emerged in Thy1 derived groups (p < 0.001), while thermal hyperalgesia occurred in all groups (p < 0.001). Importantly, consistent findings across TG+ and TG- groups suggest that the effects are mediated by the genetic background rather than transgene manipulation itself. Surprisingly, TM training restored mechanical and thermal sensation to baseline levels in TG+ mice with SCI. This behavioral profile and responsiveness to chronic training will be important to consider when choosing models to study the mechanisms underlying sensorimotor recovery after SCI.
Collapse
Affiliation(s)
- Timothy D Faw
- 1 Neuroscience Graduate Program, The Ohio State University , Columbus, Ohio.,2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - Jessica K Lerch
- 3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio.,4 Department of Neuroscience, The Ohio State University , Columbus, Ohio
| | - Tyler T Thaxton
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - Rochelle J Deibert
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - Lesley C Fisher
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| | - D Michele Basso
- 2 School of Health and Rehabilitation Sciences, The Ohio State University , Columbus, Ohio.,3 Center for Brain and Spinal Cord Repair, The Ohio State University , Columbus, Ohio
| |
Collapse
|
66
|
Functional Consequences of Synapse Remodeling Following Astrocyte-Specific Regulation of Ephrin-B1 in the Adult Hippocampus. J Neurosci 2018; 38:5710-5726. [PMID: 29793972 DOI: 10.1523/jneurosci.3618-17.2018] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/13/2018] [Accepted: 05/15/2018] [Indexed: 01/22/2023] Open
Abstract
Astrocyte-derived factors can control synapse formation and functions, making astrocytes an attractive target for regulating neuronal circuits and associated behaviors. Abnormal astrocyte-neuronal interactions are also implicated in neurodevelopmental disorders and neurodegenerative diseases associated with impaired learning and memory. However, little is known about astrocyte-mediated mechanisms that regulate learning and memory. Here, we propose astrocytic ephrin-B1 as a regulator of synaptogenesis in adult hippocampus and mouse learning behaviors. We found that astrocyte-specific ablation of ephrin-B1 in male mice triggers an increase in the density of immature dendritic spines and excitatory synaptic sites in the adult CA1 hippocampus. However, the prevalence of immature dendritic spines is associated with decreased evoked postsynaptic firing responses in CA1 pyramidal neurons, suggesting impaired maturation of these newly formed and potentially silent synapses or increased excitatory drive on the inhibitory neurons resulting in the overall decreased postsynaptic firing. Nevertheless, astrocyte-specific ephrin-B1 knock-out male mice exhibit normal acquisition of fear memory but enhanced contextual fear memory recall. In contrast, overexpression of astrocytic ephrin-B1 in the adult CA1 hippocampus leads to the loss of dendritic spines, reduced excitatory input, and impaired contextual memory retention. Our results suggest that astrocytic ephrin-B1 may compete with neuronal ephrin-B1 and mediate excitatory synapse elimination through its interactions with neuronal EphB receptors. Indeed, a deletion of neuronal EphB receptors impairs the ability of astrocytes expressing functional ephrin-B1 to engulf synaptosomes in vitro Our findings demonstrate that astrocytic ephrin-B1 regulates long-term contextual memory by restricting new synapse formation in the adult hippocampus.SIGNIFICANCE STATEMENT These studies address a gap in our knowledge of astrocyte-mediated regulation of learning and memory by unveiling a new role for ephrin-B1 in astrocytes and elucidating new mechanisms by which astrocytes regulate learning. Our studies explore the mechanisms underlying astrocyte regulation of hippocampal circuit remodeling during learning using new genetic tools that target ephrin-B signaling in astrocytes in vivo On a subcellular level, astrocytic ephrin-B1 may compete with neuronal ephrin-B1 and trigger astrocyte-mediated elimination of EphB receptor-containing synapses. Given the role EphB receptors play in neurodevelopmental disorders and neurodegenerative diseases, these findings establish a foundation for future studies of astrocyte-mediated synaptogenesis in clinically relevant conditions that can help to guide the development of clinical applications for a variety of neurological disorders.
Collapse
|
67
|
Yang JS, Wei HX, Chen PP, Wu G. Roles of Eph/ephrin bidirectional signaling in central nervous system injury and recovery. Exp Ther Med 2018. [PMID: 29456630 DOI: 10.3892/etm.2018.5702.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Multiple cellular components are involved in the complex pathological process following central nervous system (CNS) injury, including neurons, glial cells and endothelial cells. Previous studies and neurotherapeutic clinical trials have assessed the molecular mechanisms that underlie neuronal cell death following CNS injury. However, this approach has largely failed to reduce CNS damage or improve the functional recovery of patients. Erythropoietin-producing human hepatocellular (Eph) receptors and ephrin ligands have attracted considerable attention since their discovery, due to their extensive distribution and unique bidirectional signaling between astrocytes and neurons. Previous studies have investigated the roles of Eph/ephrin bidirectional signaling in the developing central nervous system. It was determined that Eph/ephrin bidirectional signaling is expressed in various CNS regions and cell types, and that it serves diverse roles in the adult CNS. In the present review, the roles of Eph/ephrin bidirectional signaling in CNS injuries are assessed.
Collapse
Affiliation(s)
- Jin-Shan Yang
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| | - Hui-Xing Wei
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| | - Ping-Ping Chen
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| | - Gang Wu
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| |
Collapse
|
68
|
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.
Collapse
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.
| |
Collapse
|
69
|
Yang JS, Wei HX, Chen PP, Wu G. Roles of Eph/ephrin bidirectional signaling in central nervous system injury and recovery. Exp Ther Med 2018; 15:2219-2227. [PMID: 29456630 PMCID: PMC5795627 DOI: 10.3892/etm.2018.5702] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 10/26/2017] [Indexed: 12/12/2022] Open
Abstract
Multiple cellular components are involved in the complex pathological process following central nervous system (CNS) injury, including neurons, glial cells and endothelial cells. Previous studies and neurotherapeutic clinical trials have assessed the molecular mechanisms that underlie neuronal cell death following CNS injury. However, this approach has largely failed to reduce CNS damage or improve the functional recovery of patients. Erythropoietin-producing human hepatocellular (Eph) receptors and ephrin ligands have attracted considerable attention since their discovery, due to their extensive distribution and unique bidirectional signaling between astrocytes and neurons. Previous studies have investigated the roles of Eph/ephrin bidirectional signaling in the developing central nervous system. It was determined that Eph/ephrin bidirectional signaling is expressed in various CNS regions and cell types, and that it serves diverse roles in the adult CNS. In the present review, the roles of Eph/ephrin bidirectional signaling in CNS injuries are assessed.
Collapse
Affiliation(s)
- Jin-Shan Yang
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| | - Hui-Xing Wei
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| | - Ping-Ping Chen
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| | - Gang Wu
- Department of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
| |
Collapse
|
70
|
Kim SY, Hsu JE, Husbands LC, Kleim JA, Jones TA. Coordinated Plasticity of Synapses and Astrocytes Underlies Practice-Driven Functional Vicariation in Peri-Infarct Motor Cortex. J Neurosci 2018; 38:93-107. [PMID: 29133435 PMCID: PMC5761439 DOI: 10.1523/jneurosci.1295-17.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 10/05/2017] [Accepted: 11/03/2017] [Indexed: 01/05/2023] Open
Abstract
Motor rehabilitative training after stroke can improve motor function and promote topographical reorganization of remaining motor cortical movement representations, but this reorganization follows behavioral improvements. A more detailed understanding of the neural bases of rehabilitation efficacy is needed to inform therapeutic efforts to improve it. Using a rat model of upper extremity impairments after ischemic stroke, we examined effects of motor rehabilitative training at the ultrastructural level in peri-infarct motor cortex. Extensive training in a skilled reaching task promoted improved performance and recovery of more normal movements. This was linked with greater axodendritic synapse density and ultrastructural characteristics of enhanced synaptic efficacy that were coordinated with changes in perisynaptic astrocytic processes in the border region between head and forelimb areas of peri-infarct motor cortex. Disrupting synapses and motor maps by infusions of anisomycin (ANI) into anatomically reorganized motor, but not posterior parietal, cortex eliminated behavioral gains from rehabilitative training. In contrast, ANI infusion in the equivalent cortical region of intact animals had no effect on reaching skills. These results suggest that rehabilitative training efficacy for improving manual skills is mediated by synaptic plasticity in a region of motor cortex that, before lesions, is not essential for manual skills, but becomes so as a result of the training. These findings support that experience-driven synaptic structural reorganization underlies functional vicariation in residual motor cortex after motor cortical infarcts.SIGNIFICANCE STATEMENT Stroke is a leading cause of long-term disability. Motor rehabilitation, the main treatment for physical disability, is of variable efficacy. A better understanding of neural mechanisms underlying effective motor rehabilitation would inform strategies for improving it. Here, we reveal synaptic underpinnings of effective motor rehabilitation. Rehabilitative training improved manual skill in the paretic forelimb and induced the formation of special synapse subtypes in coordination with structural changes in astrocytes, a glial cell that influences neural communication. These changes were found in a region that is nonessential for manual skill in intact animals, but came to mediate this skill due to training after stroke. Therefore, motor rehabilitation efficacy depends on synaptic changes that enable remaining brain regions to assume new functions.
Collapse
Affiliation(s)
- Soo Young Kim
- Department of Integrative Biology, University of California, Berkeley, California 94720,
| | - J Edward Hsu
- Department of Neurosurgery, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030
- Institute for Neuroscience
| | | | - Jeffrey A Kleim
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287
| | - Theresa A Jones
- Institute for Neuroscience
- Psychology Department, University of Texas, Austin, Texas 78712, and
| |
Collapse
|
71
|
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
Collapse
Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| |
Collapse
|
72
|
Yuferov V, Zhang Y, Liang Y, Zhao C, Randesi M, Kreek MJ. Oxycodone Self-Administration Induces Alterations in Expression of Integrin, Semaphorin and Ephrin Genes in the Mouse Striatum. Front Psychiatry 2018; 9:257. [PMID: 29946272 PMCID: PMC6005861 DOI: 10.3389/fpsyt.2018.00257] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 05/24/2018] [Indexed: 11/28/2022] Open
Abstract
Oxycodone is one a commonly used medication for pain, and is also a widely abused prescription opioid, like other short-acting MOPr agonists. Neurochemical and structural adaptations in brain following chronic MOPr-agonist administration are thought to underlie pathogenesis and persistence of opiate addiction. Many axon guidance molecules, such as integrins, semaphorins, and ephrins may contribute to oxycodone-induced neuroadaptations through alterations in axon-target connections and synaptogenesis, that may be implicated in the behaviors associated with opiate addiction. However, little is known about this important area. The aim of this study is to investigate alterations in expression of selected integrin, semaphorin, ephrins, netrin, and slit genes in the nucleus accumbens (NAc) and caudate putamen (CPu) of mice following extended 14-day oxycodone self-administration (SA), using RNAseq. Methods: Total RNA from the NAc and CPu were isolated from adult male C57BL/6J mice within 1 h after the last session of oxycodone in a 14-day self-administration paradigm (4h/day, 0.25 mg/kg/infusion, FR1) or from yoked saline controls. Gene expressions were examined using RNA sequencing (RNA-Seq) technology. RNA-Seq libraries were prepared using Illumina's TruSeq® Stranded Total RNA LT kit. The reads were aligned to the mouse reference genome (version mm10) using STAR. DESeq2 was applied to the counts of protein coding genes to estimate the fold change between the treatment groups. False Discovery Rate (FDR) q < 0.1 were used to select genes that have a significant expression change. For selection of a subset of genes related to axon guidance pathway, REACTOME was used. Results: Among 38 known genes of the integrin, semaphorin, and ephrin gene families, RNA-seq data revealed up-regulation of six genes in the NAc: heterodimer receptor, integrins Itgal, Itgb2, and Itgam, and its ligand semaphorin Sema7a, two semaphorin receptors, plexins Plxnd1 and Plxdc1. There was down-regulation of eight genes in this region: two integrin genes Itga3 and Itgb8, semaphorins Sema3c, Sema4g, Sema6a, Sema6d, semaphorin receptor neuropilin Nrp2, and ephrin receptor Epha3. In the CPu, there were five differentially expressed axon guidance genes: up-regulation of three integrin genes, Itgal, Itgb2, Itga1, and down-regulation of Itga9 and ephrin Efna3 were thus observed. No significant alterations in expression of Netrin-1 or Slit were observed. Conclusion: We provide evidence for alterations in the expression of selective axon guidance genes in adult mouse brain following chronic self-administration of oxycodone. Further examination of oxycodone-induced changes in the expression of these specific axon guidance molecules and integrin genes in relation to behavior may provide new insights into development of addiction to oxycodone.
Collapse
Affiliation(s)
- Vadim Yuferov
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, NY, United States
| | - Yong Zhang
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, NY, United States
| | - Yupu Liang
- Research Bioinformatics, Clinical and Translational Science Award, The Rockefeller University, New York, NY, United States
| | - Connie Zhao
- Genomic Resource Center, The Rockefeller University, New York, NY, United States
| | - Matthew Randesi
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, NY, United States
| | - Mary J Kreek
- Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, NY, United States
| |
Collapse
|
73
|
Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 899] [Impact Index Per Article: 149.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
Collapse
Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| |
Collapse
|
74
|
Liu X, Tian F, Wang S, Wang F, Xiong L. Astrocyte Autophagy Flux Protects Neurons Against Oxygen-Glucose Deprivation and Ischemic/Reperfusion Injury. Rejuvenation Res 2017; 21:405-415. [PMID: 29125039 DOI: 10.1089/rej.2017.1999] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The role of autophagy varies with the type of acute brain injury. In general, autophagy mediates a clear neuroprotective effect in intoxication caused by various psychoactive agents, subarachnoid hemorrhage and spinal cord injury. In contrast, autophagic cell death has also been reported to actively contribute to neuronal loss in neonatal hypoxic ischemic encephalopathy. However, it still remains to be determined whether autophagy pays a cytoprotective or a cytotoxic role in stroke. Previous studies focused primarily on the role of neurons rather than the role of astrocytes in brain injury. Thus, it is unknown whether modulating the autophagy flux of astrocytes contributes to improving neuronal survival after stroke. In the current study, we investigated the time course of autophagy flux in vitro using cocultured astrocytes and neurons exposed to oxygen-glucose deprivation/reoxygenation, which mimicked the process of ischemia/reperfusion. Autophagy flux of astrocytes was regulated by treatment with the autophagy inducer rapamycin, autophagy inhibitor 3-methyladenine, and the transduction of small interfering RNA against autophagy-related gene 5. In addition, AAV-GFAP-ATG7 was used to induce astrocyte autophagy flux in mice subjected to focal cerebral ischemia. We found that induction of autophagy flux of astrocytes in vitro enhanced the viability of neurons and decreased neuronal apoptosis. Furthermore, induction of astrocyte autophagy flux in mice improved neurological outcomes. In contrast, inhibition of autophagy flux in astrocytes decreased the viability of neurons and increased neuronal apoptosis. These results suggest that upregulation of autophagy flux in astrocytes may contribute to endogenous neuroprotective and neurorecovery mechanisms after stroke.
Collapse
Affiliation(s)
- Xue Liu
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University , Xi'an, China
| | - Fengfeng Tian
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University , Xi'an, China
| | - Shiquan Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University , Xi'an, China
| | - Feng Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University , Xi'an, China
| | - Lize Xiong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University , Xi'an, China
| |
Collapse
|
75
|
Ronzano R. [Astrocytes and microglia: active players in synaptic plasticity]. Med Sci (Paris) 2017; 33:1071-1078. [PMID: 29261495 DOI: 10.1051/medsci/20173312014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Synaptic plasticity consists in a change in structure and composition of presynaptic and postsynaptic compartments. For a long time, synaptic plasticity had been thought as a neuronal mechanism only under the control of neural network activity. However, recently, with the growing knowledge about glial physiology, plasticity has been reviewed as a mechanism influenced by the synaptic environment. Thus, it appears that astrocytes and microglia modulate these mechanisms modifying neural environment by clearance of neurotransmitters, releasing essential factors and modulating inflammation. Moreover, glia can change its own activity and the expression pattern of many factors that modulate synaptic plasticity according to the environment. Hence, these populations of "non-neuronal" cells in the central nervous system seem to be active players in synaptic plasticity. This review discusses how glia modulates synaptic plasticity focusing on long-term potentiation and depression, and questions the role of the signaling processes between astrocytes and microglia in these mechanisms.
Collapse
Affiliation(s)
- Rémi Ronzano
- École normale supérieure de Cachan, université Paris-Saclay, 61, avenue du Président Wilson, 94235 Cachan Cedex, France
| |
Collapse
|
76
|
Meyer LC, Paisley CE, Mohamed E, Bigbee JW, Kordula T, Richard H, Lutfy K, Sato-Bigbee C. Novel role of the nociceptin system as a regulator of glutamate transporter expression in developing astrocytes. Glia 2017; 65:2003-2023. [PMID: 28906039 PMCID: PMC5766282 DOI: 10.1002/glia.23210] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 07/03/2017] [Accepted: 08/04/2017] [Indexed: 12/30/2022]
Abstract
Our previous results showed that oligodendrocyte development is regulated by both nociceptin and its G-protein coupled receptor, the nociceptin/orphanin FQ receptor (NOR). The present in vitro and in vivo findings show that nociceptin plays a crucial conserved role regulating the levels of the glutamate/aspartate transporter GLAST/EAAT1 in both human and rodent brain astrocytes. This nociceptin-mediated response takes place during a critical developmental window that coincides with the early stages of astrocyte maturation. GLAST/EAAT1 upregulation by nociceptin is mediated by NOR and the downstream participation of a complex signaling cascade that involves the interaction of several kinase systems, including PI-3K/AKT, mTOR, and JAK. Because GLAST is the main glutamate transporter during brain maturation, these novel findings suggest that nociceptin plays a crucial role in regulating the function of early astrocytes and their capacity to support glutamate homeostasis in the developing brain.
Collapse
Affiliation(s)
- Logan C Meyer
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Caitlin E Paisley
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Esraa Mohamed
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - John W Bigbee
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Tomasz Kordula
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Hope Richard
- Department of Pathology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Kabirullah Lutfy
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California
| | - Carmen Sato-Bigbee
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| |
Collapse
|
77
|
Liao Z, Tao Y, Guo X, Cheng D, Wang F, Liu X, Ma L. Fear Conditioning Downregulates Rac1 Activity in the Basolateral Amygdala Astrocytes to Facilitate the Formation of Fear Memory. Front Mol Neurosci 2017; 10:396. [PMID: 29230165 PMCID: PMC5712045 DOI: 10.3389/fnmol.2017.00396] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/13/2017] [Indexed: 12/16/2022] Open
Abstract
Astrocytes are well known to scale synaptic structural and functional plasticity, while the role in learning and memory, such as conditioned fear memory, is poorly elucidated. Here, using pharmacological approach, we find that fluorocitrate (FC) significantly inhibits the acquisition of fear memory, suggesting that astrocyte activity is required for fear memory formation. We further demonstrate that fear conditioning downregulates astrocytic Rac1 activity in basolateral amygdala (BLA) in mice and promotes astrocyte structural plasticity. Ablation of astrocytic Rac1 in BLA promotes fear memory acquisition, while overexpression or constitutive activation of astrocytic Rac1 attenuates fear memory acquisition. Furthermore, temporal activation of Rac1 by photoactivatable Rac1 (Rac1-PA) induces structural alterations in astrocytes and in vivo activation of Rac1 in BLA astrocytes during fear conditioning attenuates the formation of fear memory. Taken together, our study demonstrates that fear conditioning-induced suppression of BLA astrocytic Rac1 activity, associated with astrocyte structural plasticity, is required for the formation of conditioned fear memory.
Collapse
Affiliation(s)
- Zhaohui Liao
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Yezheng Tao
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Xiaomu Guo
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Deqin Cheng
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Feifei Wang
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Xing Liu
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Lan Ma
- The State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, The Institutes of Brain Science, and The Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| |
Collapse
|
78
|
Huang TY, Zhao Y, Jiang LL, Li X, Liu Y, Sun Y, Piña-Crespo JC, Zhu B, Masliah E, Willnow TE, Pasquale EB, Xu H. SORLA attenuates EphA4 signaling and amyloid β-induced neurodegeneration. J Exp Med 2017; 214:3669-3685. [PMID: 29114064 PMCID: PMC5716044 DOI: 10.1084/jem.20171413] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/12/2017] [Accepted: 09/15/2017] [Indexed: 11/04/2022] Open
Abstract
Sortilin-related receptor with LDLR class A repeats (SORLA, SORL1, or LR11) is a genetic risk factor associated with Alzheimer's disease (AD). Although SORLA is known to regulate trafficking of the amyloid β (Aβ) precursor protein to decrease levels of proteotoxic Aβ oligomers, whether SORLA can counteract synaptic dysfunction induced by Aβ oligomers remains unclear. Here, we show that SORLA interacts with the EphA4 receptor tyrosine kinase and attenuates ephrinA1 ligand-induced EphA4 clustering and activation to limit downstream effects of EphA4 signaling in neurons. Consistent with these findings, SORLA transgenic mice, compared with WT mice, exhibit decreased EphA4 activation and redistribution to postsynaptic densities, with milder deficits in long-term potentiation and memory induced by Aβ oligomers. Importantly, we detected elevated levels of active EphA4 in human AD brains, where EphA4 activation is inversely correlated with SORLA/EphA4 association. These results demonstrate a novel role for SORLA as a physiological and pathological EphA4 modulator, which attenuates synaptotoxic EphA4 activation and cognitive impairment associated with Aβ-induced neurodegeneration in AD.
Collapse
Affiliation(s)
- Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Yingjun Zhao
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Lu-Lin Jiang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Xiaoguang Li
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Yan Liu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA.,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Yu Sun
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Juan C Piña-Crespo
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Bing Zhu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Eliezer Masliah
- Department of Pathology, University of California, San Diego, La Jolla, CA.,Department of Neuroscience, University of California, San Diego, La Jolla, CA
| | | | - Elena B Pasquale
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA.,Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA .,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| |
Collapse
|
79
|
Subcellular Distribution of HDAC1 in Neurotoxic Conditions Is Dependent on Serine Phosphorylation. J Neurosci 2017; 37:7547-7559. [PMID: 28663197 DOI: 10.1523/jneurosci.3000-16.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 05/25/2017] [Accepted: 06/18/2017] [Indexed: 11/21/2022] Open
Abstract
Calcium-dependent nuclear export of histone deacetylase 1 (HDAC1) was shown previously to precede axonal damage in culture, but the in vivo relevance of these findings and the potential posttranslational modifications of HDAC1 remained elusive. Using acute hippocampal slices from mice of either sex with genetic conditional ablation of Hdac1 in CA1 hippocampal neurons (i.e., Camk2a-cre;Hdac1fl/fl), we show significantly diminished axonal damage in response to neurotoxic stimuli. The protective effect of Hdac1 ablation was detected also in CA3 neurons in Grik4-cre;Hdac1fl/f mice, which were more resistant to the excitotoxic damage induced by intraventricular injection of kainic acid. The amino acid residues modulating HDAC1 subcellular localization were identified by site-directed mutagenesis, which identified serine residues 421 and 423 as critical for its nuclear localization. The physiological phosphorylation of HDAC1 was decreased by neurotoxic stimuli, which stimulated the phosphatase enzymatic activity of calcineurin. Treatment of neurons with the calcineurin inhibitors FK506 or cyclosporin A resulted in nuclear accumulation of phospho-HDAC1 and was neuroprotective. Together, our data identify HDAC1 and the phosphorylation of specific serine residues in the molecule as potential targets for neuroprotection.SIGNIFICANCE STATEMENT The importance of histone deacetylation in normal brain functions and pathological conditions is unquestionable, yet the molecular mechanisms responsible for the neurotoxic potential of histone deacetylase 1 (HDAC1) and its subcellular localization are not fully understood. Here, we use transgenic lines to define the in vivo relevance of HDAC1 and identify calcineurin-dependent serine dephosphorylation as the signal modulating the neurotoxic role of HDAC1 in response to neurotoxic stimuli.
Collapse
|
80
|
Neural Activity-Dependent Regulation of Radial Glial Filopodial Motility Is Mediated by Glial cGMP-Dependent Protein Kinase 1 and Contributes to Synapse Maturation in the Developing Visual System. J Neurosci 2017; 36:5279-88. [PMID: 27170125 DOI: 10.1523/jneurosci.3787-15.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/30/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Radial glia in the developing optic tectum extend highly dynamic filopodial protrusions within the tectal neuropil, the motility of which has previously been shown to be sensitive to neural activity and nitric oxide (NO) release. Using in vivo two-photon microscopy, we performed time-lapse imaging of radial glial cells and measured filopodial motility in the intact albino Xenopus laevis tadpole. Application of MK801 to block neuronal NMDA receptor (NMDAR) currents confirmed a significant reduction in radial glial filopodial motility. This reduction did not occur in glial cells expressing a dominant-negative form of cGMP-dependent protein kinase 1 (PKG1), and was prevented by elevation of cGMP levels with the phosphodiesterase type 5 inhibitor sildenafil. These results suggest that neuronal NMDAR activation results in the release of NO, which in turn modulates PKG1 activation in glial cells to control filopodial motility. We further showed that interfering with the function of the small GTPases Rac1 or RhoA, known to be regulated by PKG1 phosphorylation, decreased motility or eliminated filopodial processes respectively. These manipulations led to profound defects in excitatory synaptic development and maturation of neighboring neurons. SIGNIFICANCE STATEMENT Radial glia in the developing brain extend motile filopodia from their primary stalk. Neuronal NMDA receptor activity controls glial motility through intercellular activation of cGMP-dependent protein kinase 1 (PKG1) signaling in glial cells. Manipulating PKG1, Rac1, or RhoA signaling in radial glia in vivo to eliminate glial filopodia or impair glial motility profoundly impacted synaptogenesis and circuit maturation.
Collapse
|
81
|
Freyburger M, Poirier G, Carrier J, Mongrain V. Shorter duration of non-rapid eye movement sleep slow waves in EphA4 knockout mice. J Sleep Res 2017; 26:539-546. [PMID: 28488395 DOI: 10.1111/jsr.12532] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 02/24/2017] [Indexed: 11/27/2022]
Abstract
Slow waves occurring during non-rapid eye movement sleep have been associated with neurobehavioural performance and memory. In addition, the duration of previous wakefulness and sleep impacts characteristics of these slow waves. However, molecular mechanisms regulating the dynamics of slow-wave characteristics remain poorly understood. The EphA4 receptor regulates glutamatergic transmission and synaptic plasticity, which have both been linked to sleep slow waves. To investigate if EphA4 regulates slow-wave characteristics during non-rapid eye movement sleep, we compared individual parameters of slow waves between EphA4 knockout mice and wild-type littermates under baseline conditions and after a 6-h sleep deprivation. We observed that, compared with wild-type mice, knockout mice display a shorter duration of positive and negative phases of slow waves under baseline conditions and after sleep deprivation. However, the mutation did not change slow-wave density, amplitude and slope, and did not affect the sleep deprivation-dependent changes in slow-wave characteristics, suggesting that EphA4 is not involved in the response to elevated sleep pressure. Our present findings suggest a role for EphA4 in shaping cortical oscillations during sleep that is independent from sleep need.
Collapse
Affiliation(s)
- Marlène Freyburger
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| | - Gaétan Poirier
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada
| | - Julie Carrier
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Psychology, Université de Montréal, Montreal, QC, Canada
| | - Valérie Mongrain
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada.,Department of Neuroscience, Université de Montréal, Montreal, QC, Canada
| |
Collapse
|
82
|
Kebir O, Chaumette B, Rivollier F, Miozzo F, Lemieux Perreault LP, Barhdadi A, Provost S, Plaze M, Bourgin J, Gaillard R, Mezger V, Dubé MP, Krebs MO. Methylomic changes during conversion to psychosis. Mol Psychiatry 2017; 22:512-518. [PMID: 27113994 PMCID: PMC5378806 DOI: 10.1038/mp.2016.53] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 02/28/2016] [Accepted: 03/02/2016] [Indexed: 12/12/2022]
Abstract
The onset of psychosis is the consequence of complex interactions between genetic vulnerability to psychosis and response to environmental and/or maturational changes. Epigenetics is hypothesized to mediate the interplay between genes and environment leading to the onset of psychosis. We believe we performed the first longitudinal prospective study of genomic DNA methylation during psychotic transition in help-seeking young individuals referred to a specialized outpatient unit for early detection of psychosis and enrolled in a 1-year follow-up. We used Infinium HumanMethylation450 BeadChip array after bisulfite conversion and analyzed longitudinal variations in methylation at 411 947 cytosine-phosphate-guanine (CpG) sites. Conversion to psychosis was associated with specific methylation changes. Changes in DNA methylation were significantly different between converters and non-converters in two regions: one located in 1q21.1 and a cluster of six CpG located in GSTM5 gene promoter. Methylation data were confirmed by pyrosequencing in the same population. The 100 top CpGs associated with conversion to psychosis were subjected to exploratory analyses regarding the related gene networks and their capacity to distinguish between converters and non-converters. Cluster analysis showed that the top CpG sites correctly distinguished between converters and non-converters. In this first study of methylation during conversion to psychosis, we found that alterations preferentially occurred in gene promoters and pathways relevant for psychosis, including oxidative stress regulation, axon guidance and inflammatory pathways. Although independent replications are warranted to reach definitive conclusions, these results already support that longitudinal variations in DNA methylation may reflect the biological mechanisms that precipitate some prodromal individuals into full-blown psychosis, under the influence of environmental factors and maturational processes at adolescence.
Collapse
Affiliation(s)
- O Kebir
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - B Chaumette
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - F Rivollier
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - F Miozzo
- CNRS, UMR7216 Épigénétique et Destin Cellulaire, Paris, France,Université Paris Diderot, Sorbonne Paris Cité, Paris, France,Département Hospitalo-Universitaire DHU PROTECT, Paris, France
| | - L P Lemieux Perreault
- Université de Montréal, Beaulieu-Saucier Pharmacogenomics Center, Montréal Heart Institute, Montréal, QC, Canada
| | - A Barhdadi
- Université de Montréal, Beaulieu-Saucier Pharmacogenomics Center, Montréal Heart Institute, Montréal, QC, Canada
| | - S Provost
- Université de Montréal, Beaulieu-Saucier Pharmacogenomics Center, Montréal Heart Institute, Montréal, QC, Canada
| | - M Plaze
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - J Bourgin
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | | | - R Gaillard
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France
| | - V Mezger
- CNRS, UMR7216 Épigénétique et Destin Cellulaire, Paris, France,Université Paris Diderot, Sorbonne Paris Cité, Paris, France,Département Hospitalo-Universitaire DHU PROTECT, Paris, France
| | - M-P Dubé
- Université de Montréal, Beaulieu-Saucier Pharmacogenomics Center, Montréal Heart Institute, Montréal, QC, Canada
| | - M-O Krebs
- Université Paris Descartes, PRES Université Paris Sorbonne Paris Cité, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,INSERM, Laboratoire de Physiopathologie des Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, UMR S 894, Paris, France,CNRS, GDR3557-Institut de Psychiatrie, Paris, France,Faculté de Médecine Paris Descartes, Centre Hospitalier Sainte-Anne, Service Hospitalo-Universitaire, Paris, France,Laboratoire de Physiopathologie de Maladies Psychiatriques, Centre de Psychiatrie et Neurosciences, Service Hospitalo-Universitaire, INSERM U894—Université Paris Descartes, 2 ter rue d'Alesia, Paris 75014, France. E-mail:
| |
Collapse
|
83
|
Ephrins in astrocytes: synaptic erasers on stage. Oncotarget 2017; 8:5676-5677. [PMID: 28031541 PMCID: PMC5351576 DOI: 10.18632/oncotarget.14237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
84
|
Abstract
Aquaporins (AQPs ) mediate water flux between the four distinct water compartments in the central nervous system (CNS). In the present chapter, we mainly focus on the expression and function of the 9 AQPs expressed in the CNS, which include five members of aquaporin subfamily: AQP1, AQP4, AQP5, AQP6, and AQP8; three members of aquaglyceroporin subfamily: AQP3, AQP7, and AQP9; and one member of superaquaporin subfamily: AQP11. In addition, AQP1, AQP2 and AQP4 expressed in the peripheral nervous system (PNS) are also reviewed. AQP4, the predominant water channel in the CNS, is involved both in the astrocyte swelling of cytotoxic edema and the resolution of vasogenic edema, and is of pivotal importance in the pathology of brain disorders such as neuromyelitis optica , brain tumors and Alzheimer's disease. Other AQPs are also involved in a variety of important physiological and pathological process in the brain. It has been suggested that AQPs could represent an important target in treatment of brain disorders like cerebral edema. Future investigations are necessary to elucidate the pathological significance of AQPs in the CNS.
Collapse
|
85
|
Rose CR, Ziemens D, Untiet V, Fahlke C. Molecular and cellular physiology of sodium-dependent glutamate transporters. Brain Res Bull 2016; 136:3-16. [PMID: 28040508 DOI: 10.1016/j.brainresbull.2016.12.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 02/04/2023]
Abstract
Glutamate is the major excitatory transmitter in the vertebrate brain. After its release from presynaptic nerve terminals, it is rapidly taken up by high-affinity sodium-dependent plasma membrane transporters. While both neurons and glial cells express these excitatory amino acid transporters (EAATs), the majority of glutamate uptake is accomplished by astrocytes, which convert synaptically-released glutamate to glutamine or feed it into their own metabolism. Glutamate uptake by astrocytes not only shapes synaptic transmission by regulating the availability of glutamate to postsynaptic neuronal receptors, but also protects neurons from hyper-excitability and subsequent excitotoxic damage. In the present review, we provide an overview of the molecular and cellular characteristics of sodium-dependent glutamate transporters and their associated anion permeation pathways, with a focus on astrocytic glutamate transport. We summarize their functional properties and roles within tripartite synapses under physiological and pathophysiological conditions, exemplifying the intricate interactions and interrelationships between neurons and glial cells in the brain.
Collapse
Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany.
| | - Daniel Ziemens
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Verena Untiet
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| | - Christoph Fahlke
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| |
Collapse
|
86
|
Ambrogini P, Betti M, Galati C, Di Palma M, Lattanzi D, Savelli D, Galli F, Cuppini R, Minelli A. α-Tocopherol and Hippocampal Neural Plasticity in Physiological and Pathological Conditions. Int J Mol Sci 2016; 17:E2107. [PMID: 27983697 PMCID: PMC5187907 DOI: 10.3390/ijms17122107] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/01/2016] [Accepted: 12/09/2016] [Indexed: 12/25/2022] Open
Abstract
Neuroplasticity is an "umbrella term" referring to the complex, multifaceted physiological processes that mediate the ongoing structural and functional modifications occurring, at various time- and size-scales, in the ever-changing immature and adult brain, and that represent the basis for fundamental neurocognitive behavioral functions; in addition, maladaptive neuroplasticity plays a role in the pathophysiology of neuropsychiatric dysfunctions. Experiential cues and several endogenous and exogenous factors can regulate neuroplasticity; among these, vitamin E, and in particular α-tocopherol (α-T), the isoform with highest bioactivity, exerts potent effects on many plasticity-related events in both the physiological and pathological brain. In this review, the role of vitamin E/α-T in regulating diverse aspects of neuroplasticity is analyzed and discussed, focusing on the hippocampus, a brain structure that remains highly plastic throughout the lifespan and is involved in cognitive functions. Vitamin E-mediated influences on hippocampal synaptic plasticity and related cognitive behavior, on post-natal development and adult hippocampal neurogenesis, as well as on cellular and molecular disruptions in kainate-induced temporal seizures are described. Besides underscoring the relevance of its antioxidant properties, non-antioxidant functions of vitamin E/α-T, mainly involving regulation of cell signaling molecules and their target proteins, have been highlighted to help interpret the possible mechanisms underlying the effects on neuroplasticity.
Collapse
Affiliation(s)
- Patrizia Ambrogini
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Michele Betti
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Claudia Galati
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Michael Di Palma
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Davide Lattanzi
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - David Savelli
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Francesco Galli
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy.
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Andrea Minelli
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| |
Collapse
|
87
|
Feng L, Shu Y, Wu Q, Liu T, Long H, Yang H, Li Y, Xiao B. EphA4 may contribute to microvessel remodeling in the hippocampal CA1 and CA3 areas in a mouse model of temporal lobe epilepsy. Mol Med Rep 2016; 15:37-46. [PMID: 27959424 PMCID: PMC5355650 DOI: 10.3892/mmr.2016.6017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 09/10/2016] [Indexed: 12/26/2022] Open
Abstract
Unclustered and pre-clustered ephrin-A5-Fc have identical anti-epileptic effects in the dentate gyrus of hippocampus in a mouse model of temporal lobe epilepsy (TLE), and act through alleviating ephrin receptor A4 (EphA4)-mediated neurogenesis and angiogenesis. However, the effects of ephrin-A5-Fcs on EphA4 and angiogenesis in Cornu Ammonis (CA)1 and CA3 areas remain unclear. In the present study, male C57BL/6 mice underwent pilocarpine-induced TLE. The expression of EphA4 and ephrin-A5 proteins was analyzed by immunohistochemistry, and the mean density and diameter of platelet endothelial cell adhesion molecule-1-labeled microvessels in CA1 and CA3 were calculated in the absence or presence of two types of ephrin-A5-Fc intrahippocampal infusion. Microvessels perpendicular to the pyramidal cell layer decreased; however, microvessels that traversed the layer increased, and became distorted and fragmented. The mean densities and diameters of microvessels gradually increased and remained greater than those in the control group at 56 days post-status epilepticus (SE). The upregulation of EphA4 and ephrin-A5 proteins began at 7 days and was maintained until 28 days, subsequently decreasing slightly at 56 days post-SE. Blockade of EphA4 by unclustered-ephrin-A5-Fc effected a reduction in the mean density and mean diameter of microvessels in the CA1 and CA3 areas; conversely, activation of EphA4 by clustered-ephrin-A5-Fc induced an increase in these values. Ephrin-A5 ligand binding to EphA4 receptor may contribute to angiogenesis during epileptogenesis in the hippocampal CA1 and CA3 areas.
Collapse
Affiliation(s)
- Li Feng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yi Shu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - Qian Wu
- Department of Neurology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
| | - Tiantian Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Hongyu Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yi Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| |
Collapse
|
88
|
Broad KD, Hassell J, Fleiss B, Kawano G, Ezzati M, Rocha-Ferreira E, Hristova M, Bennett K, Fierens I, Burnett R, Chaban B, Alonso-Alconada D, Oliver-Taylor A, Tachsidis I, Rostami J, Gressens P, Sanders RD, Robertson NJ. Isoflurane Exposure Induces Cell Death, Microglial Activation and Modifies the Expression of Genes Supporting Neurodevelopment and Cognitive Function in the Male Newborn Piglet Brain. PLoS One 2016; 11:e0166784. [PMID: 27898690 PMCID: PMC5127656 DOI: 10.1371/journal.pone.0166784] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/03/2016] [Indexed: 12/02/2022] Open
Abstract
Exposure of the brain to general anesthesia during early infancy may adversely affect its neural and cognitive development. The mechanisms mediating this are complex, incompletely understood and may be sexually dimorphic, but include developmentally inappropriate apoptosis, inflammation and a disruption to cognitively salient gene expression. We investigated the effects of a 6h isoflurane exposure on cell death, microglial activation and gene expression in the male neonatal piglet brain. Piglets (n = 6) were randomised to: (i) naive controls or (ii) 6h isoflurane. Cell death (TUNEL and caspase-3) and microglial activation were recorded in 7 brain regions. Changes in gene expression (microarray and qPCR) were assessed in the cingulate cortex. Electroencephalography (EEG) was recorded throughout. Isoflurane anesthesia induced significant increases in cell death in the cingulate and insular cortices, caudate nucleus, thalamus, putamen, internal capsule, periventricular white matter and hippocampus. Dying cells included both neurons and oligodendrocytes. Significantly, microglial activation was observed in the insula, pyriform, hippocampus, internal capsule, caudate and thalamus. Isoflurane induced significant disruption to the expression of 79 gene transcripts, of these 26 are important for the control of transcription and 23 are important for the mediation of neural plasticity, memory formation and recall. Our observations confirm that isoflurane increases apoptosis and inflammatory responses in the neonatal piglet brain but also suggests novel additional mechanisms by which isoflurane may induce adverse neural and cognitive development by disrupting the expression of genes mediating activity dependent development of neural circuits, the predictive adaptive responses of the brain, memory formation and recall.
Collapse
Affiliation(s)
- Kevin D. Broad
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Jane Hassell
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Bobbi Fleiss
- Centre for the Developing Brain, Kings College, St Thomas’s Campus, London, United Kingdom
- Inserm, Paris, France
- University Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Go Kawano
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Mojgan Ezzati
- Institute for Women’s Health, University College London, London, United Kingdom
| | | | - Mariya Hristova
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Kate Bennett
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Igor Fierens
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Ryan Burnett
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Badr Chaban
- Institute for Women’s Health, University College London, London, United Kingdom
| | | | - Aaron Oliver-Taylor
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Ilias Tachsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Jamshid Rostami
- Institute for Women’s Health, University College London, London, United Kingdom
| | - Pierre Gressens
- Centre for the Developing Brain, Kings College, St Thomas’s Campus, London, United Kingdom
- Inserm, Paris, France
- University Paris Diderot, Sorbonne Paris Cite, Paris, France
| | - Robert D. Sanders
- Department of Anesthesiology, University of Wisconsin, Madison, United States of America
- Wellcome Department of Imaging Neuroscience, University College London, London, United Kingdom
- Surgical Outcomes Research Centre, University College London Hospital, London, United Kingdom
| | - Nicola J. Robertson
- Institute for Women’s Health, University College London, London, United Kingdom
- * E-mail:
| |
Collapse
|
89
|
O'Callaghan EK, Ballester Roig MN, Mongrain V. Cell adhesion molecules and sleep. Neurosci Res 2016; 116:29-38. [PMID: 27884699 DOI: 10.1016/j.neures.2016.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 10/26/2016] [Accepted: 10/28/2016] [Indexed: 02/06/2023]
Abstract
Cell adhesion molecules (CAMs) play essential roles in the central nervous system, where some families are involved in synaptic development and function. These synaptic adhesion molecules (SAMs) are involved in the regulation of synaptic plasticity, and the formation of neuronal networks. Recent findings from studies examining the consequences of sleep loss suggest that these molecules are candidates to act in sleep regulation. This review highlights the experimental data that lead to the identification of SAMs as potential sleep regulators, and discusses results supporting that specific SAMs are involved in different aspects of sleep regulation. Further, some potential mechanisms by which SAMs may act to regulate sleep are outlined, and the proposition that these molecules may serve as molecular machinery in the two sleep regulatory processes, the circadian and homeostatic components, is presented. Together, the data argue that SAMs regulate the neuronal plasticity that underlies sleep and wakefulness.
Collapse
Affiliation(s)
- Emma Kate O'Callaghan
- Research Centre and Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin West Blvd. Montreal, QC, H4J 1C5, Canada; Department of Neuroscience, Université de Montréal, C.P. 6128, succ. Centre-Ville, Montreal, QC, H3C 3J7, Canada
| | - Maria Neus Ballester Roig
- Research Centre and Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin West Blvd. Montreal, QC, H4J 1C5, Canada; Neurophysiology of Sleep and Biology Rhythms Laboratory, IDISPA (Health Research Foundation Illes Balears), University of Balearic Islands, Palma de Mallorca 07122, Spain
| | - Valérie Mongrain
- Research Centre and Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin West Blvd. Montreal, QC, H4J 1C5, Canada; Department of Neuroscience, Université de Montréal, C.P. 6128, succ. Centre-Ville, Montreal, QC, H3C 3J7, Canada,.
| |
Collapse
|
90
|
Reemst K, Noctor SC, Lucassen PJ, Hol EM. The Indispensable Roles of Microglia and Astrocytes during Brain Development. Front Hum Neurosci 2016; 10:566. [PMID: 27877121 PMCID: PMC5099170 DOI: 10.3389/fnhum.2016.00566] [Citation(s) in RCA: 336] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/25/2016] [Indexed: 01/17/2023] Open
Abstract
Glia are essential for brain functioning during development and in the adult brain. Here, we discuss the various roles of both microglia and astrocytes, and their interactions during brain development. Although both cells are fundamentally different in origin and function, they often affect the same developmental processes such as neuro-/gliogenesis, angiogenesis, axonal outgrowth, synaptogenesis and synaptic pruning. Due to their important instructive roles in these processes, dysfunction of microglia or astrocytes during brain development could contribute to neurodevelopmental disorders and potentially even late-onset neuropathology. A better understanding of the origin, differentiation process and developmental functions of microglia and astrocytes will help to fully appreciate their role both in the developing as well as in the adult brain, in health and disease.
Collapse
Affiliation(s)
- Kitty Reemst
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Stephen C. Noctor
- Department of Psychiatry and Behavioral Sciences, UC Davis MIND InstituteSacramento, CA, USA
| | - Paul J. Lucassen
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Elly M. Hol
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
- Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, Netherlands
- Netherlands Institute for NeuroscienceAmsterdam, Netherlands
| |
Collapse
|
91
|
Salameh AI, Hübner CA, Boron WF. Role of Cl - -HCO 3- exchanger AE3 in intracellular pH homeostasis in cultured murine hippocampal neurons, and in crosstalk to adjacent astrocytes. J Physiol 2016; 595:93-124. [PMID: 27353306 DOI: 10.1113/jp272470] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/20/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS A polymorphism of human AE3 is associated with idiopathic generalized epilepsy. Knockout of AE3 in mice lowers the threshold for triggering epileptic seizures. The explanations for these effects are elusive. Comparisons of cells from wild-type vs. AE3-/- mice show that AE3 (present in hippocampal neurons, not astrocytes; mediates HCO3- efflux) enhances intracellular pH (pHi ) recovery (decrease) from alkali loads in neurons and, surprisingly, adjacent astrocytes. During metabolic acidosis (MAc), AE3 speeds initial acidification, but limits the extent of pHi decrease in neurons and astrocytes. AE3 speeds re-alkalization after removal of MAc in neurons and astrocytes, and speeds neuronal pHi recovery from an ammonium prepulse-induced acid load. We propose that neuronal AE3 indirectly increases acid extrusion in (a) neurons via Cl- loading, and (b) astrocytes by somehow enhancing NBCe1 (major acid extruder). The latter would enhance depolarization-induced alkalinization of astrocytes, and extracellular acidification, and thereby reduce susceptibility to epileptic seizures. ABSTRACT The anion exchanger AE3, expressed in hippocampal (HC) neurons but not astrocytes, contributes to intracellular pH (pHi ) regulation by facilitating the exchange of extracellular Cl- for intracellular HCO3- . The human AE3 polymorphism A867D is associated with idiopathic generalized epilepsy. Moreover, AE3 knockout (AE3-/- ) mice are more susceptible to epileptic seizure. The mechanism of these effects has been unclear because the starting pHi in AE3-/- and wild-type neurons is indistinguishable. The purpose of the present study was to use AE3-/- mice to investigate the role of AE3 in pHi homeostasis in HC neurons, co-cultured with astrocytes. We find that the presence of AE3 increases the acidification rate constant during pHi recovery from intracellular alkaline loads imposed by reducing [CO2 ]. The presence of AE3 also speeds intracellular acidification during the early phase of metabolic acidosis (MAc), not just in neurons but, surprisingly, in adjacent astrocytes. Additionally, AE3 contributes to braking the decrease in pHi later during MAc in both neurons and astrocytes. Paradoxically, AE3 enhances intracellular re-alkalization after MAc removal in neurons and astrocytes, and pHi recovery from an ammonium prepulse-induced acid load in neurons. The effects of AE3 knockout on astrocytic pHi homeostasis in MAc-related assays require the presence of neurons, and are consistent with the hypothesis that the AE3 knockout reduces functional expression of astrocytic NBCe1. These findings suggest a new type of neuron-astrocyte communication, based on the expression of AE3 in neurons, which could explain how AE3 reduces seizure susceptibility.
Collapse
Affiliation(s)
- Ahlam I Salameh
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | | | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| |
Collapse
|
92
|
Serradj N, Martin JH. Motor Experience Reprograms Development of a Genetically-Altered Bilateral Corticospinal Motor Circuit. PLoS One 2016; 11:e0163775. [PMID: 27673329 PMCID: PMC5038944 DOI: 10.1371/journal.pone.0163775] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 09/14/2016] [Indexed: 11/19/2022] Open
Abstract
Evidence suggests that motor experience plays a role in shaping development of the corticospinal system and voluntary motor control, which is a key motor function of the system. Here we used a mouse model with conditional forebrain deletion of the gene for EphA4 (Emx1-Cre:EphA4tm2Kldr), which regulates development of the laterality of corticospinal tract (CST). We combined study of Emx1-Cre:EphA4tm2Kldr with unilateral forelimb constraint during development to expand our understanding of experience-dependent CST development from both basic and translational perspectives. This mouse develops dense ipsilateral CST projections, a bilateral motor cortex motor representation, and bilateral motor phenotypes. Together these phenotypes can be used as readouts of corticospinal system organization and function and the changes brought about by experience. The Emx1-Cre:EphA4tm2Kldr mouse shares features with the common developmental disorder cerebral palsy: bilateral voluntary motor impairments and bilateral CST miswiring. Emx1-Cre:EphA4tm2Kldr mice with typical motor experiences during development display the bilateral phenotype of “mirror” reaching, because of a strongly bilateral motor cortex motor representation and a bilateral CST. By contrast, Emx1-Cre:EphA4tm2Kldr mice that experienced unilateral forelimb constraint from P1 to P30 and tested at maturity had a more contralateral motor cortex motor representation in each hemisphere; more lateralized CST projections; and substantially more lateralized/independent reaching movements. Changes in CST organization and function in this model can be explained by reduced synaptic competition of the CST from the side without developmental forelimb motor experiences. Using this model we show that unilateral constraint largely abrogated the effects of the genetic mutation on CST projections and thus demonstrates how robust and persistent experience-dependent development can be for the establishment of corticospinal system connections and voluntary control. Further, our findings inform the mechanisms of and strategies for developing behavioral therapies to treat bilateral movement impairments and CST miswiring in cerebral palsy.
Collapse
Affiliation(s)
- Najet Serradj
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY, United States of America
| | - John H. Martin
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY, United States of America
- Neuroscience Program, Graduate Center of the City University of New York, New York, NY, United States of America
- * E-mail:
| |
Collapse
|
93
|
Regional Regulation of Purkinje Cell Dendritic Spines by Integrins and Eph/Ephrins. PLoS One 2016; 11:e0158558. [PMID: 27518800 PMCID: PMC4982633 DOI: 10.1371/journal.pone.0158558] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/19/2016] [Indexed: 02/02/2023] Open
Abstract
Climbing fibres and parallel fibres compete for dendritic space on Purkinje cells in the cerebellum. Normally, climbing fibres populate the proximal dendrites, where they suppress the multiple small spines typical of parallel fibres, leading to their replacement by the few large spines that contact climbing fibres. Previous work has shown that ephrins acting via EphA4 are a signal for this change in spine type and density. We have used an in vitro culture model in which to investigate the ephrin effect on Purkinje cell dendritic spines and the role of integrins in these changes. We found that integrins α3, α5 and β4 are present in many of the dendritic spines of cultured Purkinje cells. pFAK, the main downstream signalling molecule from integrins, has a similar distribution, although the intenstity of pFAK staining and the percentage of pFAK+ spines was consistently higher in the proximal dendrites. Activating integrins with Mg2+ led to an increase in the intensity of pFAK staining and an increase in the proportion of pFAK+ spines in both the proximal and distal dendrites, but no change in spine length, density or morphology. Blocking integrin binding with an RGD-containing peptide led to a reduction in spine length, with more stubby spines on both proximal and distal dendrites. Treatment of the cultures with ephrinA3-Fc chimera suppressed dendritic spines specifically on the proximal dendrites and there was also a decrease of pFAK in spines on this domain. This effect was blocked by simultaneous activation of integrins with Mn2+. We conclude that Eph/ephrin signaling regulates proximal dendritic spines in Purkinje cells by inactivating integrin downstream signalling.
Collapse
|
94
|
Mohd-Zin SW, Abdullah NL, Abdullah A, Greene NDE, Cheah PS, Ling KH, Yusof H, Marwan AI, Williams SM, York KT, Ahmad-Annuar A, Abdul-Aziz NM. Identification of the genomic mutation in Epha4(rb-2J/rb-2J) mice. Genome 2016; 59:439-48. [PMID: 27373307 DOI: 10.1139/gen-2015-0142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The EphA4 receptor tyrosine kinase is involved in numerous cell-signalling activities during embryonic development. EphA4 has the ability to bind to both types of ephrin ligands, the ephrinAs and ephrinBs. The C57BL/6J-Epha4rb-2J/GrsrJ strain, denoted Epha4(rb-2J/rb-2J), is a spontaneous mouse mutant that arose at The Jackson Laboratory. These mutants exhibited a synchronous hind limb locomotion defect or "hopping gait" phenotype, which is also characteristic of EphA4 null mice. Genetic complementation experiments suggested that Epha4(rb-2J) corresponds to an allele of EphA4, but details of the genomic defect in this mouse mutant are currently unavailable. We found a single base-pair deletion in exon 9 resulting in a frame shift mutation that subsequently resulted in a premature stop codon. Analysis of the predicted structure of the truncated protein suggests that both the kinase and sterile α motif (SAM) domains are absent. Definitive determination of genotype is needed for experimental studies of mice carrying the Epha4(rb-2J) allele, and we have also developed a method to ease detection of the mutation through RFLP. Eph-ephrin family members are reportedly expressed as numerous isoforms. Hence, delineation of the specific mutation in EphA4 in this strain is important for further functional studies, such as protein-protein interactions, immunostaining and gene compensatory studies, investigating the mechanism underlying the effects of altered function of Eph family of receptor tyrosine kinases on phenotype.
Collapse
Affiliation(s)
- Siti W Mohd-Zin
- a Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Nor-Linda Abdullah
- a Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Aminah Abdullah
- b School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 Selangor, Malaysia
| | - Nicholas D E Greene
- c Birth Defects Research Centre, Developmental Biology and Cancer Programme, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Pike-See Cheah
- d Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor DE, Malaysia
| | - King-Hwa Ling
- d Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor DE, Malaysia
- e Department of Obstetrics and Gynaecology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor DE, Malaysia
| | - Hadri Yusof
- d Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor DE, Malaysia
| | - Ahmed I Marwan
- f Department of Surgery, University of Colorado Denver, Anschutz Medical Campus, 12700 E 17th Ave., Aurora, CO 80045, USA
| | - Sarah M Williams
- f Department of Surgery, University of Colorado Denver, Anschutz Medical Campus, 12700 E 17th Ave., Aurora, CO 80045, USA
| | - Kerri T York
- f Department of Surgery, University of Colorado Denver, Anschutz Medical Campus, 12700 E 17th Ave., Aurora, CO 80045, USA
| | - Azlina Ahmad-Annuar
- g Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Noraishah M Abdul-Aziz
- a Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| |
Collapse
|
95
|
Korte M, Schmitz D. Cellular and System Biology of Memory: Timing, Molecules, and Beyond. Physiol Rev 2016; 96:647-93. [PMID: 26960344 DOI: 10.1152/physrev.00010.2015] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The storage of information in the mammalian nervous systems is dependent on a delicate balance between change and stability of neuronal networks. The induction and maintenance of processes that lead to changes in synaptic strength to a multistep process which can lead to long-lasting changes, which starts and ends with a highly choreographed and perfectly timed dance of molecules in different cell types of the central nervous system. This is accompanied by synchronization of specific networks, resulting in the generation of characteristic "macroscopic" rhythmic electrical fields, whose characteristic frequencies correspond to certain activity and information-processing states of the brain. Molecular events and macroscopic fields influence each other reciprocally. We review here cellular processes of synaptic plasticity, particularly functional and structural changes, and focus on timing events that are important for the initial memory acquisition, as well as mechanisms of short- and long-term memory storage. Then, we cover the importance of epigenetic events on the long-time range. Furthermore, we consider how brain rhythms at the network level participate in processes of information storage and by what means they participating in it. Finally, we examine memory consolidation at the system level during processes of sleep.
Collapse
Affiliation(s)
- Martin Korte
- Zoological Institute, Division of Cellular Neurobiology, Braunschweig, Germany; Helmholtz Centre for Infection Research, AG NIND, Braunschweig, Germany; and Neuroscience Research Centre, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Dietmar Schmitz
- Zoological Institute, Division of Cellular Neurobiology, Braunschweig, Germany; Helmholtz Centre for Infection Research, AG NIND, Braunschweig, Germany; and Neuroscience Research Centre, Charité Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
96
|
Tanasic S, Mattusch C, Wagner EM, Eder M, Rupprecht R, Rammes G, Di Benedetto B. Desipramine targets astrocytes to attenuate synaptic plasticity via modulation of the ephrinA3/EphA4 signalling. Neuropharmacology 2016; 105:154-163. [DOI: 10.1016/j.neuropharm.2016.01.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
|
97
|
Hu YW, Jiang JJ, Yan-Gao, Wang RY, Tu GJ. MicroRNA-210 promotes sensory axon regeneration of adult mice in vivo and in vitro. Neurosci Lett 2016; 622:61-6. [PMID: 27102143 DOI: 10.1016/j.neulet.2016.04.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 12/20/2022]
Abstract
Axon regeneration as a critical step in nerve repairing and remodeling after peripheral nerve injury relies on regulation of gene expression. MicroRNAs are emerging to be important epigenetic regulators of gene expression to control axon regeneration. Here we used a novel in vivo electroporation approach to transfect microRNA-210 (miR-210) or siRNAs to adult mice dorsal root ganglion (DRG) neurons, measured the axon length 3days after sciatic nerve crush or dissociated DRG cultures in vitro to detect the effect of miR-210 in sensory axon regeneration. Importantly, we found that miR-210 overexpression could promote sensory axon regeneration and inhibit apoptsosis by ephrin-A3 (EFNA3). In addition, inhibition of endogenous miR-210 in DRG neurons impaired axon regeneration in vitro and in vivo, the regulatory effect of miR-210 was mediated by increased expression of EFNA3 because downregulation of EFNA3 fully rescued axon regeneration. We thus demonstrate that miR-210 is a new physiological regulator of sensory axon regeneration, and EFNA3 may be the functional target of miR-210. We conclude that miR-210 may play an important role in sensory axon regeneration.
Collapse
Affiliation(s)
- Yi-Wen Hu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110000, China; Guilin Medical University, Guilin, Guangxi, 541001, China
| | - Jing-Jing Jiang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Yan-Gao
- Guilin Medical University, Guilin, Guangxi, 541001, China
| | - Rui-Ying Wang
- Guilin Medical University, Guilin, Guangxi, 541001, China
| | - Guan-Jun Tu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110000, China.
| |
Collapse
|
98
|
Cullen CL, Young KM. How Does Transcranial Magnetic Stimulation Influence Glial Cells in the Central Nervous System? Front Neural Circuits 2016; 10:26. [PMID: 27092058 PMCID: PMC4820444 DOI: 10.3389/fncir.2016.00026] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/23/2016] [Indexed: 12/13/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) is widely used in the clinic, and while it has a direct effect on neuronal excitability, the beneficial effects experienced by patients are likely to include the indirect activation of other cell types. Research conducted over the past two decades has made it increasingly clear that a population of non-neuronal cells, collectively known as glia, respond to and facilitate neuronal signaling. Each glial cell type has the ability to respond to electrical activity directly or indirectly, making them likely cellular effectors of TMS. TMS has been shown to enhance adult neural stem and progenitor cell (NSPC) proliferation, but the effect on cell survival and differentiation is less certain. Furthermore there is limited information regarding the response of astrocytes and microglia to TMS, and a complete paucity of data relating to the response of oligodendrocyte-lineage cells to this treatment. However, due to the critical and yet multifaceted role of glial cells in the central nervous system (CNS), the influence that TMS has on glial cells is certainly an area that warrants careful examination.
Collapse
Affiliation(s)
- Carlie L. Cullen
- Menzies Institute for Medical Research, University of TasmaniaHobart, TAS, Australia
| | - Kaylene M. Young
- Menzies Institute for Medical Research, University of TasmaniaHobart, TAS, Australia
| |
Collapse
|
99
|
Iwadate Y, Fukuda K, Matsutani T, Saeki N. Intrinsic protective mechanisms of the neuron-glia network against glioma invasion. J Clin Neurosci 2016; 26:19-25. [DOI: 10.1016/j.jocn.2015.07.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 10/25/2022]
|
100
|
Danka Mohammed CP, Rhee H, Phee B, Kim K, Kim H, Lee H, Park JH, Jung JH, Kim JY, Kim H, Park SK, Nam HG, Kim K. miR-204 downregulates EphB2 in aging mouse hippocampal neurons. Aging Cell 2016; 15:380-8. [PMID: 26799631 PMCID: PMC4783348 DOI: 10.1111/acel.12444] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2015] [Indexed: 11/28/2022] Open
Abstract
Hippocampal synaptic function and plasticity deteriorate with age, often resulting in learning and memory deficits. As MicroRNAs (miRNAs) are important regulators of neuronal protein expression, we examined whether miRNAs may contribute to this age‐associated decline in hippocampal function. We first compared the small RNA transcriptome of hippocampal tissues from young and old mice. Among 269 hippocampal miRNAs, 80 were differentially expressed (≥ twofold) among the age groups. We focused on 36 miRNAs upregulated in the old mice compared with those in the young mice. The potential targets of these 36 miRNAs included 11 critical Eph/Ephrin synaptic signaling components. The expression levels of several genes in the Eph/Ephrin pathway, including EphB2, were significantly downregulated in the aged hippocampus. EphB2 is a known regulator of synaptic plasticity in hippocampal neurons, in part by regulating the surface expression of the NMDA receptor NR1 subunit. We found that EphB2 is a direct target of miR‐204 among miRNAs that were upregulated with age. The transfection of primary hippocampal neurons with a miR‐204 mimic suppressed both EphB2 mRNA and protein expression and reduced the surface expression of NR1. Transfection of miR‐204 also decreased the total expression of NR1. miR‐204 induces senescence‐like phenotype in fully matured neurons as evidenced by an increase in p16‐positive cells. We suggest that aging is accompanied by the upregulation of miR‐204 in the hippocampus, which downregulates EphB2 and results in reduced surface and total NR1 expression. This mechanism may contribute to age‐associated decline in hippocampal synaptic plasticity and the related cognitive functions.
Collapse
Affiliation(s)
- Chand Parvez Danka Mohammed
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
- Department of New Biology DGIST Daegu 711‐873 Korea
- Department of Life Sciences POSTECH Pohang 790‐784 Korea
| | | | - Bong‐Kwan Phee
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
| | - Kunhyung Kim
- Department of New Biology DGIST Daegu 711‐873 Korea
| | - Hee‐Jin Kim
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
| | - Hyehyeon Lee
- Department of New Biology DGIST Daegu 711‐873 Korea
| | | | | | - Jeong Yeon Kim
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
| | - Hyoung‐Chin Kim
- Korea Research Institute of Bioscience and Biotechnology Ochang 363‐883 Korea
| | - Sang Ki Park
- Department of Life Sciences POSTECH Pohang 790‐784 Korea
| | - Hong Gil Nam
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
- Department of New Biology DGIST Daegu 711‐873 Korea
| | - Keetae Kim
- Department of New Biology DGIST Daegu 711‐873 Korea
| |
Collapse
|