1
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Todd AC, Hardingham GE. The Regulation of Astrocytic Glutamate Transporters in Health and Neurodegenerative Diseases. Int J Mol Sci 2020; 21:E9607. [PMID: 33348528 PMCID: PMC7766851 DOI: 10.3390/ijms21249607] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022] Open
Abstract
The astrocytic glutamate transporters excitatory amino acid transporters 1 and 2 (EAAT1 and EAAT2) play a key role in nervous system function to maintain extracellular glutamate levels at low levels. In physiology, this is essential for the rapid uptake of synaptically released glutamate, maintaining the temporal fidelity of synaptic transmission. However, EAAT1/2 hypo-expression or hypo-function are implicated in several disorders, including epilepsy and neurodegenerative diseases, as well as being observed naturally with aging. This not only disrupts synaptic information transmission, but in extremis leads to extracellular glutamate accumulation and excitotoxicity. A key facet of EAAT1/2 expression in astrocytes is a requirement for signals from other brain cell types in order to maintain their expression. Recent evidence has shown a prominent role for contact-dependent neuron-to-astrocyte and/or endothelial cell-to-astrocyte Notch signalling for inducing and maintaining the expression of these astrocytic glutamate transporters. The relevance of this non-cell-autonomous dependence to age- and neurodegenerative disease-associated decline in astrocytic EAAT expression is discussed, plus the implications for disease progression and putative therapeutic strategies.
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Affiliation(s)
- Alison C. Todd
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Giles E. Hardingham
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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2
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Salazar JL, Yang SA, Yamamoto S. Post-Developmental Roles of Notch Signaling in the Nervous System. Biomolecules 2020; 10:biom10070985. [PMID: 32630239 PMCID: PMC7408554 DOI: 10.3390/biom10070985] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/14/2022] Open
Abstract
Since its discovery in Drosophila, the Notch signaling pathway has been studied in numerous developmental contexts in diverse multicellular organisms. The role of Notch signaling in nervous system development has been extensively investigated by numerous scientists, partially because many of the core Notch signaling components were initially identified through their dramatic ‘neurogenic’ phenotype of developing fruit fly embryos. Components of the Notch signaling pathway continue to be expressed in mature neurons and glia cells, which is suggestive of a role in the post-developmental nervous system. The Notch pathway has been, so far, implicated in learning and memory, social behavior, addiction, and other complex behaviors using genetic model organisms including Drosophila and mice. Additionally, Notch signaling has been shown to play a modulatory role in several neurodegenerative disease model animals and in mediating neural toxicity of several environmental factors. In this paper, we summarize the knowledge pertaining to the post-developmental roles of Notch signaling in the nervous system with a focus on discoveries made using the fruit fly as a model system as well as relevant studies in C elegans, mouse, rat, and cellular models. Since components of this pathway have been implicated in the pathogenesis of numerous psychiatric and neurodegenerative disorders in human, understanding the role of Notch signaling in the mature brain using model organisms will likely provide novel insights into the mechanisms underlying these diseases.
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Affiliation(s)
- Jose L. Salazar
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX 77030, USA; (J.L.S.); (S.-A.Y.)
| | - Sheng-An Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX 77030, USA; (J.L.S.); (S.-A.Y.)
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX 77030, USA; (J.L.S.); (S.-A.Y.)
- Department of Neuroscience, BCM, Houston, TX 77030, USA
- Program in Developmental Biology, BCM, Houston, TX 77030, USA
- Development, Disease Models & Therapeutics Graduate Program, BCM, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-832-824-8119
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3
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Ho DM, Artavanis-Tsakonas S, Louvi A. The Notch pathway in CNS homeostasis and neurodegeneration. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2019; 9:e358. [PMID: 31502763 DOI: 10.1002/wdev.358] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/19/2019] [Accepted: 06/23/2019] [Indexed: 12/19/2022]
Abstract
The role of the Notch signaling pathway in neural development has been well established over many years. More recent studies, however, have demonstrated that Notch continues to be expressed and active throughout adulthood in many areas of the central nervous system. Notch signals have been implicated in adult neurogenesis, memory formation, and synaptic plasticity in the adult organism, as well as linked to acute brain trauma and chronic neurodegenerative conditions. NOTCH3 mutations are responsible for the most common form of hereditary stroke, the progressive disorder cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. Notch has also been associated with several progressive neurodegenerative diseases, including Alzheimer's disease, multiple sclerosis, and amyotrophic lateral sclerosis. Although numerous studies link Notch activity with CNS homeostasis and neurodegenerative diseases, the data thus far are primarily correlative, rather than functional. Nevertheless, the evidence for Notch pathway activity in specific neural cellular contexts is strong, and certainly intriguing, and points to the possibility that the pathway carries therapeutic promise. This article is categorized under: Nervous System Development > Flies Signaling Pathways > Cell Fate Signaling Nervous System Development > Vertebrates: General Principles.
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Affiliation(s)
- Diana M Ho
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | | | - Angeliki Louvi
- Departments of Neurosurgery and Neuroscience and Program on Neurogenetics, Yale School of Medicine, New Haven, Connecticut
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4
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Wei Y, Pandian GN, Yu Z, Zou T, Li Y, Darokar J, Hashiya K, Bando T, Sugiyama H. Synthetic DNA-Binding Inhibitor of HES1 Alters the Notch Signaling Pathway and Induces Neuronal Differentiation. ACS OMEGA 2018; 3:3608-3616. [PMID: 30023873 PMCID: PMC6045482 DOI: 10.1021/acsomega.8b00220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 03/12/2018] [Indexed: 05/02/2023]
Abstract
Synthetic DNA-binding inhibitors capable of gaining precise control over neurogenesis factors could obviate the current clinical barriers associated with the use of small molecules in regenerative medicine. Here, we report the design and bioefficacy of the synthetic ligand PIP-RBPJ-1, which caused promoter-specific suppression of neurogenesis-associated HES1 and its downstream genes. Furthermore, PIP-RBPJ-1 alone altered the neural-system-associated Notch-signaling factors and remarkably induced neurogenesis with an efficiency that was comparable to that of a conventional approach.
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Affiliation(s)
- Yulei Wei
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
| | - Ganesh N. Pandian
- World
Premier International Research Center, Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University, Yoshida-Ushinomiyacho, 606-8501 Kyoto, Japan
- E-mail: . Phone: +81-075-753-4002 (G.N.P.)
| | - Zutao Yu
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
| | - Tingting Zou
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
| | - Yue Li
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
| | - Jayant Darokar
- Department
of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, 110-016 New Delhi, India
| | - Kaori Hashiya
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
| | - Toshikazu Bando
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
| | - Hiroshi Sugiyama
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, 606-8502 Kyoto, Japan
- World
Premier International Research Center, Institute for Integrated Cell-Material
Sciences (WPI-iCeMS), Kyoto University, Yoshida-Ushinomiyacho, 606-8501 Kyoto, Japan
- E-mail: . Phone: +81-075-753-4002 (H.S.)
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5
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Siebel C, Lendahl U. Notch Signaling in Development, Tissue Homeostasis, and Disease. Physiol Rev 2017; 97:1235-1294. [PMID: 28794168 DOI: 10.1152/physrev.00005.2017] [Citation(s) in RCA: 598] [Impact Index Per Article: 85.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 02/07/2023] Open
Abstract
Notch signaling is an evolutionarily highly conserved signaling mechanism, but in contrast to signaling pathways such as Wnt, Sonic Hedgehog, and BMP/TGF-β, Notch signaling occurs via cell-cell communication, where transmembrane ligands on one cell activate transmembrane receptors on a juxtaposed cell. Originally discovered through mutations in Drosophila more than 100 yr ago, and with the first Notch gene cloned more than 30 yr ago, we are still gaining new insights into the broad effects of Notch signaling in organisms across the metazoan spectrum and its requirement for normal development of most organs in the body. In this review, we provide an overview of the Notch signaling mechanism at the molecular level and discuss how the pathway, which is architecturally quite simple, is able to engage in the control of cell fates in a broad variety of cell types. We discuss the current understanding of how Notch signaling can become derailed, either by direct mutations or by aberrant regulation, and the expanding spectrum of diseases and cancers that is a consequence of Notch dysregulation. Finally, we explore the emerging field of Notch in the control of tissue homeostasis, with examples from skin, liver, lung, intestine, and the vasculature.
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Affiliation(s)
- Chris Siebel
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Urban Lendahl
- Department of Discovery Oncology, Genentech Inc., DNA Way, South San Francisco, California; and Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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6
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Hayashi Y, Nishimune H, Hozumi K, Saga Y, Harada A, Yuzaki M, Iwatsubo T, Kopan R, Tomita T. A novel non-canonical Notch signaling regulates expression of synaptic vesicle proteins in excitatory neurons. Sci Rep 2016; 6:23969. [PMID: 27040987 PMCID: PMC4819173 DOI: 10.1038/srep23969] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/17/2016] [Indexed: 12/17/2022] Open
Abstract
Notch signaling plays crucial roles for cellular differentiation during development through γ-secretase-dependent intramembrane proteolysis followed by transcription of target genes. Although recent studies implicate that Notch regulates synaptic plasticity or cognitive performance, the molecular mechanism how Notch works in mature neurons remains uncertain. Here we demonstrate that a novel Notch signaling is involved in expression of synaptic proteins in postmitotic neurons. Levels of several synaptic vesicle proteins including synaptophysin 1 and VGLUT1 were increased when neurons were cocultured with Notch ligands-expressing NIH3T3 cells. Neuron-specific deletion of Notch genes decreased these proteins, suggesting that Notch signaling maintains the expression of synaptic vesicle proteins in a cell-autonomous manner. Unexpectedly, cGMP-dependent protein kinase (PKG) inhibitor, but not γ-secretase inhibitor, abolished the elevation of synaptic vesicle proteins, suggesting that generation of Notch intracellular domain is dispensable for this function. These data uncover a ligand-dependent, but γ-secretase-independent, non-canonical Notch signaling involved in presynaptic protein expression in postmitotic neurons.
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Affiliation(s)
- Yukari Hayashi
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.,Department of Physiology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas Medical School, Kansas City, KS 66160, USA
| | - Katsuto Hozumi
- Department of Immunology, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Yumiko Saga
- Division of Mammalian Development, National Institute of Genetics, Shizuoka 411-8540, Japan.,Department of Genetics, SOKENDAI, Shizuoka 411-8540, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Takeshi Iwatsubo
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Raphael Kopan
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.,Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
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7
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Turkoz M, Townsend RR, Kopan R. The Notch Intracellular Domain Has an RBPj-Independent Role during Mouse Hair Follicular Development. J Invest Dermatol 2016; 136:1106-1115. [PMID: 26940862 DOI: 10.1016/j.jid.2016.02.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 01/15/2016] [Accepted: 02/07/2016] [Indexed: 01/02/2023]
Abstract
Ligand-dependent activation, γ-secretase-processed cleavage, and recombining binding protein Jk (RBPj)-mediated downstream transcriptional activities of Notch receptors constitute the "canonical" Notch signaling pathway, which is essential for skin organogenesis. However, in Msx2-Cre mice, keratinocyte-specific deletion of the Rbpj gene in utero produced a significantly milder phenotype than either global Notch or γ-secretase loss. Herein, we investigated the underlying mechanisms for this apparent noncanonical signal using mouse genetics. We found no evidence that ligand back-signaling contributed to skin organogenesis. The perdurance of RBPj protein did not establish an epigenetic memory of a canonical signal in the youngest epidermal stem cells, and Notch targets were not derepressed. We provide evidence that γ-secretase-dependent but RBPj-independent Notch intracellular domain activity operating in the first hair follicles is responsible for a delay in follicular destruction, which results in lower serum thymic stromal lymphopoietin levels, milder B-cell lymphoproliferative disease, and improved survival in Msx2-Cre(+/tg);Rbpj(f/f) mice. Minimal amounts of the Notch intracellular domain were sufficient for rescue, which was not mediated by transcription, suggesting that the Notch intracellular domain is acting through a novel mechanism.
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Affiliation(s)
- Mustafa Turkoz
- Division of Developmental Biology, Children's Hospital Medical Center, Cincinnati, Ohio, USA; Department of Developmental Biology, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - R Reid Townsend
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Raphael Kopan
- Division of Developmental Biology, Children's Hospital Medical Center, Cincinnati, Ohio, USA; Department of Developmental Biology, Washington University School of Medicine, Saint Louis, Missouri, USA.
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8
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Kidd S, Struhl G, Lieber T. Notch is required in adult Drosophila sensory neurons for morphological and functional plasticity of the olfactory circuit. PLoS Genet 2015; 11:e1005244. [PMID: 26011623 PMCID: PMC4444342 DOI: 10.1371/journal.pgen.1005244] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/26/2015] [Indexed: 12/20/2022] Open
Abstract
Olfactory receptor neurons (ORNs) convey odor information to the central brain, but like other sensory neurons were thought to play a passive role in memory formation and storage. Here we show that Notch, part of an evolutionarily conserved intercellular signaling pathway, is required in adult Drosophila ORNs for the structural and functional plasticity of olfactory glomeruli that is induced by chronic odor exposure. Specifically, we show that Notch activity in ORNs is necessary for the odor specific increase in the volume of glomeruli that occurs as a consequence of prolonged odor exposure. Calcium imaging experiments indicate that Notch in ORNs is also required for the chronic odor induced changes in the physiology of ORNs and the ensuing changes in the physiological response of their second order projection neurons (PNs). We further show that Notch in ORNs acts by both canonical cleavage-dependent and non-canonical cleavage-independent pathways. The Notch ligand Delta (Dl) in PNs switches the balance between the pathways. These data define a circuit whereby, in conjunction with odor, N activity in the periphery regulates the activity of neurons in the central brain and Dl in the central brain regulates N activity in the periphery. Our work highlights the importance of experience dependent plasticity at the first olfactory synapse. Appropriate behavioral responses to changing environmental signals, such as odors, are essential for an organism’s survival. In Drosophila odors are detected by olfactory receptor neurons (ORNs) that synapse with second order projection neurons (PNs) and local interneurons in morphologically identifiable neuropils in the antennal lobe called glomeruli. Chronic odor exposure leads to changes in animal behavior as well as to changes in the activity of neurons in the olfactory circuit and increases in the volume of glomeruli. Here, we establish that Notch, an evolutionarily conserved transmembrane receptor that plays profound and pervasive roles in animal development, is required in adult Drosophila ORNs for functional and morphological plasticity in response to chronic odor exposure. These findings are significant because they point to a role for Notch in regulating activity dependent plasticity. Furthermore, we show that in regulating the odor dependent change in glomerular volume, Notch acts by both non-canonical, cleavage-independent and canonical, cleavage-dependent mechanisms, with the Notch ligand Delta in PNs switching the balance between the pathways. Because both the Notch pathway and the processing of olfactory information are highly conserved between flies and vertebrates these findings are likely to be of general relevance.
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Affiliation(s)
- Simon Kidd
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Gary Struhl
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Toby Lieber
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
- * E-mail:
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9
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Abstract
Memory is a temporally evolving molecular and structural process, which involves changes from local synapses to complex neural networks. There is increasing evidence for an involvement of developmental pathways in regulating synaptic communication in the adult nervous system. Notch signaling has been implicated in memory formation in a variety of species. Nevertheless, the mechanism of Notch underlying memory consolidation remains poorly understood. In this commentary, besides offering an overview of the advances in the field of Notch in memory, we highlight some of the weaknesses of the studies and attempt to cast light on the apparent discrepancies on the role of Notch in memory. We believe that future studies, employing high-throughput technologies and targeted Notch loss and gain of function animal models, will reveal the mechanisms of Notch dependent plasticity and resolve whether this signaling pathway is implicated in the cognitive deficit associated with dementia.
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Affiliation(s)
- Swananda Marathe
- Department of Medicine, Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
| | - Lavinia Alberi
- Department of Medicine, Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
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10
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Marathe S, Liu S, Brai E, Kaczarowski M, Alberi L. Notch signaling in response to excitotoxicity induces neurodegeneration via erroneous cell cycle reentry. Cell Death Differ 2015; 22:1775-84. [PMID: 25822340 DOI: 10.1038/cdd.2015.23] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/26/2015] [Accepted: 02/11/2015] [Indexed: 02/06/2023] Open
Abstract
Neurological disorders such as Alzheimer's disease, stroke and epilepsy are currently marred by the lack of effective treatments to prevent neuronal death. Erroneous cell cycle reentry (CCR) is hypothesized to have a causative role in neurodegeneration. We show that forcing S-phase reentry in cultured hippocampal neurons is sufficient to induce neurodegeneration. We found that kainic-acid treatment in vivo induces erroneous CCR and neuronal death through a Notch-dependent mechanism. Ablating Notch signaling in neurons provides neuroprotection against kainic acid-induced neuronal death. We further show that kainic-acid treatment activates Notch signaling, which increases the bioavailability of CyclinD1 through Akt/GSK3β pathway, leading to aberrant CCR via activation of CyclinD1-Rb-E2F1 axis. In addition, pharmacological blockade of this pathway at critical steps is sufficient to confer resistance to kainic acid-induced neurotoxicity in mice. Taken together, our results demonstrate that excitotoxicity leads to neuronal death in a Notch-dependent manner through erroneous CCR.
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Affiliation(s)
- S Marathe
- Department of Medicine, Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
| | - S Liu
- Receptor Biology Section, NINDS/NIH, Bethesda, MD, USA
| | - E Brai
- Department of Medicine, Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
| | - M Kaczarowski
- Department of Medicine, Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
| | - L Alberi
- Department of Medicine, Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
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11
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Liu S, Wang Y, Worley PF, Mattson MP, Gaiano N. The canonical Notch pathway effector RBP-J regulates neuronal plasticity and expression of GABA transporters in hippocampal networks. Hippocampus 2015; 25:670-8. [PMID: 25515406 DOI: 10.1002/hipo.22402] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2014] [Indexed: 01/28/2023]
Abstract
Activation of the Notch pathway in neurons is essential for learning and memory in various species from invertebrates to mammals. However, it remains unclear how Notch signaling regulates neuronal plasticity, and whether the transcriptional regulator and canonical pathway effector RBP-J plays a role. Here, we report that conditional disruption of RBP-J in the postnatal hippocampus leads to defects in long-term potentiation, long-term depression, and in learning and memory. Using gene expression profiling and chromatin immunoprecipitation, we identified two GABA transporters, GAT2 and BGT1, as putative Notch/RBP-J pathway targets, which may function downstream of RBP-J to limit the accumulation of GABA in the Schaffer collateral pathway. Our results reveal an essential role for canonical Notch/RBP-J signaling in hippocampal synaptic plasticity and suggest that role, at least in part, is mediated by the regulation of GABAergic signaling.
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Affiliation(s)
- Shuxi Liu
- Neuroregeneration Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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12
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Abstract
Memory is a temporally evolving molecular and structural process, which involves changes from local synapses to complex neural networks. There is increasing evidence for an involvement of developmental pathways in regulating synaptic communication in the adult nervous system. Notch signaling has been implicated in memory formation in a variety of species. Nevertheless, the mechanism of Notch in memory consolidation remains poorly understood. In this commentary, besides offering an overview of the advances in the field of Notch in memory, we highlight some of the weaknesses of the studies and attempt to cast light on some of the apparent discrepancies on the role of Notch in memory. We believe that future studies, employing high-throughput technologies and targeted Notch loss and gain of function animal models, will reveal the mechanisms of Notch-dependent plasticity and resolve whether this signaling pathway is implicated in the cognitive deficit associated with dementia.
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Affiliation(s)
- Swananda Marathe
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Lavinia Alberi
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
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13
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Zhang J, Yin JCP, Wesley CS. Notch Intracellular Domain (NICD) Suppresses Long-Term Memory Formation in Adult Drosophila Flies. Cell Mol Neurobiol 2015; 35:763-8. [PMID: 25791355 DOI: 10.1007/s10571-015-0183-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/16/2015] [Indexed: 01/09/2023]
Abstract
Notch receptor signaling is evolutionarily conserved and well known for its roles in animal development. Many studies in Drosophila have shown that Notch also performs important functions in memory formation in adult flies. An intriguing observation is that increased expression of the full-length Notch receptor (Nfull) triggers long-term memory (LTM) formation even after very weak training (single training). Canonical Notch signaling is mediated by Notch intracellular domain (NICD), but it is not known whether increased expression of NICD recapitulates the LTM enhancement induced by increased Nfull expression. Here, we report that increased NICD expression either has no impact on LTM formation or suppresses it. Furthermore, it either has no impact or decreases both the levels and activity of cAMP response element binding protein, a key factor supporting LTM. These results indicate that NICD signaling is not sufficient to explain Nfull-induced LTM enhancement. Our findings may also shed light on the molecular mechanisms of memory loss in neurological diseases associated with increased NICD expression and canonical Notch signaling.
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Affiliation(s)
- Jiabin Zhang
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, 53706, USA
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14
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Pyramidal cell selective ablation of N-methyl-D-aspartate receptor 1 causes increase in cellular and network excitability. Biol Psychiatry 2015; 77:556-68. [PMID: 25156700 PMCID: PMC4297754 DOI: 10.1016/j.biopsych.2014.06.026] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/05/2014] [Accepted: 06/22/2014] [Indexed: 12/15/2022]
Abstract
BACKGROUND Neuronal activity at gamma frequency is impaired in schizophrenia (SZ) and is considered critical for cognitive performance. Such impairments are thought to be due to reduced N-methyl-D-aspartate receptor (NMDAR)-mediated inhibition from parvalbumin interneurons, rather than a direct role of impaired NMDAR signaling on pyramidal neurons. However, recent studies suggest a direct role of pyramidal neurons in regulating gamma oscillations. In particular, a computational model has been proposed in which phasic currents from pyramidal cells could drive synchronized feedback inhibition from interneurons. As such, impairments in pyramidal neuron activity could lead to abnormal gamma oscillations. However, this computational model has not been tested experimentally and the molecular mechanisms underlying pyramidal neuron dysfunction in SZ remain unclear. METHODS In the present study, we tested the hypothesis that SZ-related phenotypes could arise from reduced NMDAR signaling in pyramidal neurons using forebrain pyramidal neuron specific NMDA receptor 1 knockout mice. RESULTS The mice displayed increased baseline gamma power, as well as sociocognitive impairments. These phenotypes were associated with increased pyramidal cell excitability due to changes in inherent membrane properties. Interestingly, mutant mice showed decreased expression of GIRK2 channels, which has been linked to increased neuronal excitability. CONCLUSIONS Our data demonstrate for the first time that NMDAR hypofunction in pyramidal cells is sufficient to cause electrophysiological, molecular, neuropathological, and behavioral changes related to SZ.
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15
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Brai E, Marathe S, Zentilin L, Giacca M, Nimpf J, Kretz R, Scotti A, Alberi L. Notch1 activity in the olfactory bulb is odour-dependent and contributes to olfactory behaviour. Eur J Neurosci 2014; 40:3436-49. [PMID: 25234246 DOI: 10.1111/ejn.12719] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/11/2014] [Accepted: 08/12/2014] [Indexed: 11/28/2022]
Abstract
Notch signalling plays an important role in synaptic plasticity, learning and memory functions in both Drosophila and rodents. In this paper, we report that this feature is not restricted to hippocampal networks but also involves the olfactory bulb (OB). Odour discrimination and olfactory learning in rodents are essential for survival. Notch1 expression is enriched in mitral cells of the mouse OB. These principal neurons are responsive to specific input odorants and relay the signal to the olfactory cortex. Olfactory stimulation activates a subset of mitral cells, which show an increase in Notch activity. In Notch1cKOKln mice, the loss of Notch1 in mitral cells affects the magnitude of the neuronal response to olfactory stimuli. In addition, Notch1cKOKln mice display reduced olfactory aversion to propionic acid as compared to wildtype controls. This indicates, for the first time, that Notch1 is involved in olfactory processing and may contribute to olfactory behaviour.
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Affiliation(s)
- Emanuele Brai
- Unit of Anatomy, Department of Medicine, University of Fribourg, Route de Gockel, 1, Fribourg, Switzerland
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Amygdala-dependent fear memory consolidation via miR-34a and Notch signaling. Neuron 2014; 83:906-18. [PMID: 25123309 DOI: 10.1016/j.neuron.2014.07.019] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2014] [Indexed: 11/23/2022]
Abstract
UNLABELLED Using an array-based approach after auditory fear conditioning and microRNA (miRNA) sponge-mediated inhibition, we identified a role for miR-34a within the basolateral amygdala (BLA) in fear memory consolidation. Luciferase assays and bioinformatics suggested the Notch pathway as a target of miR-34a. mRNA and protein levels of Notch receptors and ligands are downregulated in a time- and learning-specific manner after fear conditioning in the amygdala. Systemic and stereotaxic manipulations of the Notch pathway indicated that Notch signaling in the BLA suppresses fear memory consolidation. Impairment of fear memory consolidation after inhibition of miR-34a within the BLA is rescued by inhibiting Notch signaling. Together, these data suggest that within the BLA, a transient decrease in Notch signaling, via miR-34a regulation, is important for the consolidation of fear memory. This work expands the idea that developmental molecules have roles in adult behavior and that existing interventions targeting them hold promise for treating neuropsychiatric disorders. VIDEO ABSTRACT
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Expression of Nampt in hippocampal and cortical excitatory neurons is critical for cognitive function. J Neurosci 2014; 34:5800-15. [PMID: 24760840 DOI: 10.1523/jneurosci.4730-13.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD(+)) is an enzyme cofactor or cosubstrate in many essential biological pathways. To date, the primary source of neuronal NAD(+) has been unclear. NAD(+) can be synthesized from several different precursors, among which nicotinamide is the substrate predominantly used in mammals. The rate-limiting step in the NAD(+) biosynthetic pathway from nicotinamide is performed by nicotinamide phosphoribosyltransferase (Nampt). Here, we tested the hypothesis that neurons use intracellular Nampt-mediated NAD(+) biosynthesis by generating and evaluating mice lacking Nampt in forebrain excitatory neurons (CaMKIIαNampt(-/-) mice). CaMKIIαNampt(-/-) mice showed hippocampal and cortical atrophy, astrogliosis, microgliosis, and abnormal CA1 dendritic morphology by 2-3 months of age. Importantly, these histological changes occurred with altered intrahippocampal connectivity and abnormal behavior; including hyperactivity, some defects in motor skills, memory impairment, and reduced anxiety, but in the absence of impaired sensory processes or long-term potentiation of the Schaffer collateral pathway. These results clearly demonstrate that forebrain excitatory neurons mainly use intracellular Nampt-mediated NAD(+) biosynthesis to mediate their survival and function. Studying this particular NAD(+) biosynthetic pathway in these neurons provides critical insight into their vulnerability to pathophysiological stimuli and the development of therapeutic and preventive interventions for their preservation.
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Zhang J, Yin JCP, Wesley CS. From Drosophila development to adult: clues to Notch function in long-term memory. Front Cell Neurosci 2013; 7:222. [PMID: 24312012 PMCID: PMC3836050 DOI: 10.3389/fncel.2013.00222] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 11/03/2013] [Indexed: 12/26/2022] Open
Abstract
Notch is a cell surface receptor that is well known to mediate inter-cellular communication during animal development. Data in the field indicate that it is also involved in the formation of long-term memory (LTM) in the fully developed adults and in memory loss upon neurodegeneration. Our studies in the model organism Drosophila reveal that a non-canonical Notch-protein kinase C activity that plays critical roles in embryonic development also regulates cyclic-AMP response element binding protein during LTM formation in adults. Here we present a perspective on how the various known features of Notch function relate to LTM formation and how they might interface with elements of Wingless/Wnt signaling in this process.
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Affiliation(s)
- Jiabin Zhang
- Neuroscience Training Program, University of Wisconsin-Madison Madison, WI, USA ; Department of Genetics and Medical Genetics, University of Wisconsin-Madison Madison, WI, USA
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Anti-tau antibodies that block tau aggregate seeding in vitro markedly decrease pathology and improve cognition in vivo. Neuron 2013; 80:402-414. [PMID: 24075978 DOI: 10.1016/j.neuron.2013.07.046] [Citation(s) in RCA: 421] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2013] [Indexed: 11/20/2022]
Abstract
Tau aggregation occurs in neurodegenerative diseases including Alzheimer's disease and many other disorders collectively termed tauopathies. trans-cellular propagation of tau pathology, mediated by extracellular tau aggregates, may underlie pathogenesis of these conditions. P301S tau transgenic mice express mutant human tau protein and develop progressive tau pathology. Using a cell-based biosensor assay, we screened anti-tau monoclonal antibodies for their ability to block seeding activity present in P301S brain lysates. We infused three effective antibodies or controls into the lateral ventricle of P301S mice for 3 months. The antibodies markedly reduced hyperphosphorylated, aggregated, and insoluble tau. They also blocked development of tau seeding activity detected in brain lysates using the biosensor assay, reduced microglial activation, and improved cognitive deficits. These data imply a central role for extracellular tau aggregates in the development of pathology. They also suggest that immunotherapy specifically designed to block trans-cellular aggregate propagation will be a productive treatment strategy.
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Wozniak DF, Diggs-Andrews KA, Conyers S, Yuede CM, Dearborn JT, Brown JA, Tokuda K, Izumi Y, Zorumski CF, Gutmann DH. Motivational disturbances and effects of L-dopa administration in neurofibromatosis-1 model mice. PLoS One 2013; 8:e66024. [PMID: 23762458 PMCID: PMC3677926 DOI: 10.1371/journal.pone.0066024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 05/07/2013] [Indexed: 11/30/2022] Open
Abstract
Children with neurofibromatosis type 1 (NF1) frequently have cognitive and behavioral deficits. Some of these deficits have been successfully modeled in Nf1 genetically-engineered mice that develop optic gliomas (Nf1 OPG mice). In the current study, we show that abnormal motivational influences affect the behavior of Nf1 OPG mice, particularly with regard to their response to novel environmental stimuli. For example, Nf1 OPG mice made fewer spontaneous alternations in a Y-maze and fewer arm entries relative to WT controls. However, analysis of normalized alternation data demonstrated that these differences were not due to a spatial working memory deficit. Other reported behavioral results (e.g., open-field test, below) suggest that differential responses to novelty and/or other motivational influences may be more important determinants of these kinds of behavior than simple differences in locomotor activity/spontaneous movements. Importantly, normal long-term depression was observed in hippocampal slices from Nf1 OPG mice. Results from elevated plus maze testing showed that differences in exploratory activity between Nf1 OPG and WT control mice may be dependent on the environmental context (e.g., threatening or non-threatening) under which exploration is being measured. Nf1 OPG mice also exhibited decreased exploratory hole poking in a novel holeboard and showed abnormal olfactory preferences, although L-dopa (50 mg/kg) administration resolved the abnormal olfactory preference behaviors. Nf1 OPG mice displayed an attenuated response to a novel open field in terms of decreased ambulatory activity and rearing but only during the first 10 min of the session. Importantly, Nf1 OPG mice demonstrated investigative rearing deficits with regard to a novel hanging object suspended on one side of the field which were not rescued by L-dopa administration. Collectively, our results provide new data important for evaluating therapeutic treatments aimed at ameliorating NF1-associated cognitive/behavioral deficits.
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Affiliation(s)
- David F Wozniak
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America.
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Alberi L, Hoey SE, Brai E, Scotti AL, Marathe S. Notch signaling in the brain: in good and bad times. Ageing Res Rev 2013; 12:801-14. [PMID: 23570941 DOI: 10.1016/j.arr.2013.03.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/16/2013] [Accepted: 03/22/2013] [Indexed: 01/13/2023]
Abstract
Notch signaling is an evolutionarily conserved pathway, which is fundamental for neuronal development and specification. In the last decade, increasing evidence has pointed out an important role of this pathway beyond embryonic development, indicating that Notch also displays a critical function in the mature brain of vertebrates and invertebrates. This pathway appears to be involved in neural progenitor regulation, neuronal connectivity, synaptic plasticity and learning/memory. In addition, Notch appears to be aberrantly regulated in neurodegenerative diseases, including Alzheimer's disease and ischemic injury. The molecular mechanisms by which Notch displays these functions in the mature brain are not fully understood, but are currently the subject of intense research. In this review, we will discuss old and novel Notch targets and molecular mediators that contribute to Notch function in the mature brain and will summarize recent findings that explore the two facets of Notch signaling in brain physiology and pathology.
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Affiliation(s)
- Lavinia Alberi
- Unit of Anatomy, Department of Medicine, University of Fribourg, Switzerland.
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