351
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Buschler A, Manahan-Vaughan D. Metabotropic glutamate receptor, mGlu5, mediates enhancements of hippocampal long-term potentiation after environmental enrichment in young and old mice. Neuropharmacology 2016; 115:42-50. [PMID: 27267685 DOI: 10.1016/j.neuropharm.2016.06.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 12/24/2022]
Abstract
The metabotropic glutamate (mGlu) receptor, mGlu5, is of particular relevance for hippocampal function. It is critically required for the expression of long-term potentiation (LTP) and long-term depression (LTD), regulates neuronal oscillations, maintains the stability of place fields and is required for hippocampus-dependent memory. MGlu5-dysfunctions are associated with profound cognitive deficits in humans, and mGlu5 has been targeted as a putative cognitive enhancer. Cognitive enhancement, by means of environmental enrichment (EE) in rodents, results in improved hippocampal synaptic plasticity and memory. Here, we explored whether mGlu5 contributes to these enhancements. MGlu5-antagonism dose-dependently impaired the early phase of LTP (>4 h) in the CA1 region of young(3-4 month old) mice. Late-LTP (>24 h) was also impaired. LTP (>24 h) elicited in old (10-14 month old) mice displayed reduced sensitivity to mGlu5 antagonism. Short-term potentiation (STP, < 2 h) that was elicited by weaker afferent stimulation was unaffected by mGlu5-antagonism in both age-groups. EE significantly amplified STP (<2 h) in old and young animals, but did not increase the duration of synaptic potentiation, or promote induction of LTP. The improvement in STP was prevented by mGlu5-antagonism, in both young and old animals. These results indicate that modifications of the synapse that underlie improvements of LTP by EE require the contribution of mGlu5. Strikingly, although LTP in old mice does not critically depend on mGlu5, improvements in synaptic potentiation resulting from EE are mGlu5-dependent in old mice. Regarded in light of the known role for mGlu5 in hippocampal function and pathophysiology, these data suggest that mGlu5 regulation of synaptic information storage is pivotal to optimal hippocampal function. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Arne Buschler
- Ruhr University Bochum, Medical Faculty, Department of Neurophysiology, Bochum, Germany
| | - Denise Manahan-Vaughan
- Ruhr University Bochum, Medical Faculty, Department of Neurophysiology, Bochum, Germany.
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352
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Domains of STIP1 responsible for regulating PrPC-dependent amyloid-β oligomer toxicity. Biochem J 2016; 473:2119-30. [PMID: 27208175 DOI: 10.1042/bcj20160087] [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] [Received: 02/08/2016] [Accepted: 05/16/2016] [Indexed: 11/17/2022]
Abstract
Soluble oligomers of amyloid-beta peptide (AβO) transmit neurotoxic signals through the cellular prion protein (PrP(C)) in Alzheimer's disease (AD). Secreted stress-inducible phosphoprotein 1 (STIP1), an Hsp70 and Hsp90 cochaperone, inhibits AβO binding to PrP(C) and protects neurons from AβO-induced cell death. Here, we investigated the molecular interactions between AβO and STIP1 binding to PrP(C) and their effect on neuronal cell death. We showed that residues located in a short region of PrP (90-110) mediate AβO binding and we narrowed the major interaction in this site to amino acids 91-100. In contrast, multiple binding sites on STIP1 (DP1, TPR1 and TPR2A) contribute to PrP binding. DP1 bound the N-terminal of PrP (residues 23-95), whereas TPR1 and TPR2A showed binding to the C-terminal of PrP (residues 90-231). Importantly, only TPR1 and TPR2A directly inhibit both AβO binding to PrP and cell death. Furthermore, our structural studies reveal that TPR1 and TPR2A bind to PrP through distinct regions. The TPR2A interface was shown to be much more extensive and to partially overlap with the Hsp90 binding site. Our data show the possibility of a PrP, STIP1 and Hsp90 ternary complex, which may influence AβO-mediated cell death.
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353
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Sanderson TM, Hogg EL, Collingridge GL, Corrêa SAL. Hippocampal metabotropic glutamate receptor long-term depression in health and disease: focus on mitogen-activated protein kinase pathways. J Neurochem 2016; 139 Suppl 2:200-214. [PMID: 26923875 DOI: 10.1111/jnc.13592] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/16/2016] [Accepted: 02/21/2016] [Indexed: 12/16/2022]
Abstract
Group I metabotropic glutamate receptor (mGluR) dependent long-term depression (LTD) is a major form of synaptic plasticity underlying learning and memory. The molecular mechanisms involved in mGluR-LTD have been investigated intensively for the last two decades. In this 60th anniversary special issue article, we review the recent advances in determining the mechanisms that regulate the induction, transduction and expression of mGluR-LTD in the hippocampus, with a focus on the mitogen-activated protein kinase (MAPK) pathways. In particular we discuss the requirement of p38 MAPK and extracellular signal-regulated kinase 1/2 (ERK 1/2) activation. The recent advances in understanding the signaling cascades regulating mGluR-LTD are then related to the cognitive impairments observed in neurological disorders, such as fragile X syndrome and Alzheimer's disease. mGluR-LTD is a form of synaptic plasticity that impacts on memory formation. In the hippocampus mitogen-activated protein kinases (MAPKs) have been found to be important in mGluR-LTD. In this 60th anniversary special issue article, we review the independent and complementary roles of two classes of MAPK, p38 and ERK1/2 and link this to the aberrant mGluR-LTD that has an important role in diseases. This article is part of the 60th Anniversary special issue.
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Affiliation(s)
- Thomas M Sanderson
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Ellen L Hogg
- Bradford School of Pharmacy, Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Graham L Collingridge
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK. .,Department of Physiology, University of Toronto, Toronto, Ontario, Canada. .,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
| | - Sonia A L Corrêa
- Bradford School of Pharmacy, Faculty of Life Sciences, University of Bradford, Bradford, UK.
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354
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Freund RK, Gibson ES, Potter H, Dell'Acqua ML. Inhibition of the Motor Protein Eg5/Kinesin-5 in Amyloid β-Mediated Impairment of Hippocampal Long-Term Potentiation and Dendritic Spine Loss. Mol Pharmacol 2016; 89:552-9. [PMID: 26957206 PMCID: PMC4851299 DOI: 10.1124/mol.115.103085] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/07/2016] [Indexed: 01/09/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by neurofibrillary tangles, amyloid plaques, and neurodegeneration. However, this pathology is preceded by increased soluble amyloid beta (Aβ) 1-42 oligomers that interfere with the glutamatergic synaptic plasticity required for learning and memory, includingN-methyl-d-aspartate receptor (NMDAR)-dependent long-term potentiation (LTP). In particular, soluble Aβ(1-42) acutely inhibits LTP and chronically causes synapse loss. Many mechanisms have been proposed for Aβ-induced synaptic dysfunction, but we recently found that Aβ(1-42) inhibits the microtubule motor protein Eg5/kinesin-5. Here we compared the impacts of Aβ(1-42) and monastrol, a small-molecule Eg5 inhibitor, on LTP in hippocampal slices and synapse loss in neuronal cultures. Acute (20-minute) treatment with monastrol, like Aβ, completely inhibited LTP at doses >100 nM. In addition, 1 nM Aβ(1-42) or 50 nM monastrol inhibited LTP #x223c;50%, and when applied together caused complete LTP inhibition. At concentrations that impaired LTP, neither Aβ(1-42) nor monastrol inhibited NMDAR synaptic responses until #x223c;60 minutes, when only #x223c;25% inhibition was seen for monastrol, indicating that NMDAR inhibition was not responsible for LTP inhibition by either agent when applied for only 20 minutes. Finally, 48 hours of treatment with either 0.5-1.0μM Aβ(1-42) or 1-5μM monastrol reduced the dendritic spine/synapse density in hippocampal cultures up to a maximum of #x223c;40%, and when applied together at maximal concentrations, no additional spine loss resulted. Thus, monastrol can mimic and in some cases occlude the impact of Aβon LTP and synapse loss, suggesting that Aβinduces acute and chronic synaptic dysfunction in part through inhibiting Eg5.
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Affiliation(s)
- Ronald K Freund
- Department of Pharmacology (R.K.F., E.S.G., M.L.D.'A.), and Department Neurology (H.P.), School of Medicine, and Linda Crnic Institute for Down Syndrome (M.L.D.'A., H.P.), Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Emily S Gibson
- Department of Pharmacology (R.K.F., E.S.G., M.L.D.'A.), and Department Neurology (H.P.), School of Medicine, and Linda Crnic Institute for Down Syndrome (M.L.D.'A., H.P.), Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Huntington Potter
- Department of Pharmacology (R.K.F., E.S.G., M.L.D.'A.), and Department Neurology (H.P.), School of Medicine, and Linda Crnic Institute for Down Syndrome (M.L.D.'A., H.P.), Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Mark L Dell'Acqua
- Department of Pharmacology (R.K.F., E.S.G., M.L.D.'A.), and Department Neurology (H.P.), School of Medicine, and Linda Crnic Institute for Down Syndrome (M.L.D.'A., H.P.), Anschutz Medical Campus, University of Colorado, Aurora, Colorado
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355
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Hamilton A, Vasefi M, Vander Tuin C, McQuaid R, Anisman H, Ferguson S. Chronic Pharmacological mGluR5 Inhibition Prevents Cognitive Impairment and Reduces Pathogenesis in an Alzheimer Disease Mouse Model. Cell Rep 2016; 15:1859-65. [DOI: 10.1016/j.celrep.2016.04.077] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 02/19/2016] [Accepted: 04/20/2016] [Indexed: 01/14/2023] Open
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356
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Bruno V, Caraci F, Copani A, Matrisciano F, Nicoletti F, Battaglia G. The impact of metabotropic glutamate receptors into active neurodegenerative processes: A "dark side" in the development of new symptomatic treatments for neurologic and psychiatric disorders. Neuropharmacology 2016; 115:180-192. [PMID: 27140693 DOI: 10.1016/j.neuropharm.2016.04.044] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/22/2016] [Accepted: 04/28/2016] [Indexed: 12/17/2022]
Abstract
Metabotropic glutamate (mGlu) receptor ligands are under clinical development for the treatment of CNS disorders with high social and economic burden, such as schizophrenia, major depressive disorder (MDD), and Parkinson's disease (PD), and are promising drug candidates for the treatment of Alzheimer's disease (AD). So far, clinical studies have shown symptomatic effects of mGlu receptor ligands, but it is unknown whether these drugs act as disease modifiers or, at the opposite end, they accelerate disease progression by enhancing neurodegeneration. This is a fundamental issue in the treatment of PD and AD, and is also an emerging theme in the treatment of schizophrenia and MDD, in which neurodegeneration is also present and contribute to disease progression. Moving from in vitro data and preclinical studies, we discuss the potential impact of drugs targeting mGlu2, mGlu3, mGlu4 and mGlu5 receptor ligands on active neurodegeneration associated with AD, PD, schizophrenia, and MDD. We wish to highlight that our final comments on the best drug candidates are not influenced by commercial interests or by previous or ongoing collaborations with drug companies. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Valeria Bruno
- Department of Physiology and Pharmacology, University Sapienza, 00185 Rome, Italy; I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy.
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy; I.R.C.C.S. Associazione Oasi Maria S.S., Institute for Research on Mental Retardation and Brain Aging, 94018 Troina, Italy
| | - Agata Copani
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy; National Research Council, Institute of Biostructure and Bioimaging (IBB-CNR), 95126 Catania, Italy
| | - Francesco Matrisciano
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, USA
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University Sapienza, 00185 Rome, Italy; I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy
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357
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Phosphoinositides: Two-Path Signaling in Neuronal Response to Oligomeric Amyloid β Peptide. Mol Neurobiol 2016; 54:3236-3252. [DOI: 10.1007/s12035-016-9885-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/28/2016] [Indexed: 12/12/2022]
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358
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Schedin-Weiss S, Caesar I, Winblad B, Blom H, Tjernberg LO. Super-resolution microscopy reveals γ-secretase at both sides of the neuronal synapse. Acta Neuropathol Commun 2016; 4:29. [PMID: 27036709 PMCID: PMC4818506 DOI: 10.1186/s40478-016-0296-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 01/08/2023] Open
Abstract
The transmembrane protein assembly γ-secretase is a key protease in regulated intramembrane processing (RIP) of around 100 type-1 transmembrane proteins. Importantly, it has a pathological role in Alzheimer disease (AD) as it generates the neurotoxic amyloid β-peptide from the amyloid precursor protein (APP). Studies on γ-secretase location are therefore crucial both from a biological and a therapeutic perspective. Despite several years of efforts in many laboratories, it is not clear where in the neuron γ-secretase exerts it’s activities. Technical challenges include the fact that the active enzyme contains four protein components and that most subcellular compartments cannot be spatially resolved by traditional light microscopy. Here, we have used a powerful combination of the two nanoscopy techniques STORM and STED microscopy to visualize the location of γ-secretase in neurons using an active-site specific probe, with a focus on the synapse. We show that γ-secretase is present in both the pre-and postsynaptic compartments. We further show that the enzyme is enriched very close to the synaptic cleft in the postsynaptic membrane, as well as to NMDA receptors, demonstrating that γ-secretase is present in the postsynaptic plasma membrane. Importantly, the expression of γ-secretase increased in the pre- and postsynaptic compartments with the size of the synapse, suggesting a correlation between γ-secretase activity and synapse maturation. Thus, our data shows the synaptic location with high precision in three dimensions and settles the long-lasting debate on the synaptic location of γ-secretase.
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359
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Guntupalli S, Widagdo J, Anggono V. Amyloid-β-Induced Dysregulation of AMPA Receptor Trafficking. Neural Plast 2016; 2016:3204519. [PMID: 27073700 PMCID: PMC4814684 DOI: 10.1155/2016/3204519] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/28/2016] [Indexed: 01/22/2023] Open
Abstract
Evidence from neuropathological, genetic, animal model, and biochemical studies has indicated that the accumulation of amyloid-beta (Aβ) is associated with, and probably induces, profound neuronal changes in brain regions critical for memory and cognition in the development of Alzheimer's disease (AD). There is considerable evidence that synapses are particularly vulnerable to AD, establishing synaptic dysfunction as one of the earliest events in pathogenesis, prior to neuronal loss. It is clear that excessive Aβ levels can disrupt excitatory synaptic transmission and plasticity, mainly due to dysregulation of the AMPA and NMDA glutamate receptors in the brain. Importantly, AMPA receptors are the principal glutamate receptors that mediate fast excitatory neurotransmission. This is essential for synaptic plasticity, a cellular correlate of learning and memory, which are the cognitive functions that are most disrupted in AD. Here we review recent advances in the field and provide insights into the molecular mechanisms that underlie Aβ-induced dysfunction of AMPA receptor trafficking. This review focuses primarily on NMDA receptor- and metabotropic glutamate receptor-mediated signaling. In particular, we highlight several mechanisms that underlie synaptic long-term depression as common signaling pathways that are hijacked by the neurotoxic effects of Aβ.
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Affiliation(s)
- Sumasri Guntupalli
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jocelyn Widagdo
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Victor Anggono
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
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360
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Martins VR, Prado MAM. Prion protein in exosomes: partnering Aβ peptides and driving fibrilization. J Neurochem 2016; 137:9-11. [PMID: 26935988 DOI: 10.1111/jnc.13541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 01/16/2016] [Accepted: 01/18/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Vilma R Martins
- International Research Center, A.C.Camargo Cancer Center, São Paulo, SP, Brazil
| | - Marco A M Prado
- Department of Physiology and Pharmacology/Anatomy & Cell Biology, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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361
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Falker C, Hartmann A, Guett I, Dohler F, Altmeppen H, Betzel C, Schubert R, Thurm D, Wegwitz F, Joshi P, Verderio C, Krasemann S, Glatzel M. Exosomal cellular prion protein drives fibrillization of amyloid beta and counteracts amyloid beta-mediated neurotoxicity. J Neurochem 2016; 137:88-100. [DOI: 10.1111/jnc.13514] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 12/03/2015] [Accepted: 12/11/2015] [Indexed: 12/11/2022]
Affiliation(s)
- Clemens Falker
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Alexander Hartmann
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Inga Guett
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Frank Dohler
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Hermann Altmeppen
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Christian Betzel
- Laboratory of Structural Biology of Infection and Inflammation; Institute of Biochemistry and Molecular Biology; University of Hamburg; Hamburg Germany
- The Hamburg Centre for Ultrafast Imaging; Hamburg Germany
| | - Robin Schubert
- Laboratory of Structural Biology of Infection and Inflammation; Institute of Biochemistry and Molecular Biology; University of Hamburg; Hamburg Germany
- The Hamburg Centre for Ultrafast Imaging; Hamburg Germany
| | - Dana Thurm
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Florian Wegwitz
- Department of Translational Cancer Research; University Medical Center Göttingen; Göttingen Germany
| | | | - Claudia Verderio
- IRCCS Humanitas; Rozzano Italy
- CNR-Institute of Neuroscience; Milano Italy
| | - Susanne Krasemann
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
| | - Markus Glatzel
- Institute of Neuropathology; University Medical Center Hamburg-Eppendorf; Hamburg Germany
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362
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Bamburg JR, Bernstein BW. Actin dynamics and cofilin-actin rods in alzheimer disease. Cytoskeleton (Hoboken) 2016; 73:477-97. [PMID: 26873625 DOI: 10.1002/cm.21282] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/18/2022]
Abstract
Cytoskeletal abnormalities and synaptic loss, typical of both familial and sporadic Alzheimer disease (AD), are induced by diverse stresses such as neuroinflammation, oxidative stress, and energetic stress, each of which may be initiated or enhanced by proinflammatory cytokines or amyloid-β (Aβ) peptides. Extracellular Aβ-containing plaques and intracellular phospho-tau-containing neurofibrillary tangles are postmortem pathologies required to confirm AD and have been the focus of most studies. However, AD brain, but not normal brain, also have increased levels of cytoplasmic rod-shaped bundles of filaments composed of ADF/cofilin-actin in a 1:1 complex (rods). Cofilin, the major ADF/cofilin isoform in mammalian neurons, severs actin filaments at low cofilin/actin ratios and stabilizes filaments at high cofilin/actin ratios. It binds cooperatively to ADP-actin subunits in F-actin. Cofilin is activated by dephosphorylation and may be oxidized in stressed neurons to form disulfide-linked dimers, required for bundling cofilin-actin filaments into stable rods. Rods form within neurites causing synaptic dysfunction by sequestering cofilin, disrupting normal actin dynamics, blocking transport, and exacerbating mitochondrial membrane potential loss. Aβ and proinflammatory cytokines induce rods through a cellular prion protein-dependent activation of NADPH oxidase and production of reactive oxygen species. Here we review recent advances in our understanding of cofilin biochemistry, rod formation, and the development of cognitive deficits. We will then discuss rod formation as a molecular pathway for synapse loss that may be common between all three prominent current AD hypotheses, thus making rods an attractive therapeutic target. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- James R Bamburg
- Department of Biochemistry and Molecular Biology and the Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO.
| | - Barbara W Bernstein
- Department of Biochemistry and Molecular Biology and the Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO
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363
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LaCrosse AL, Taylor SB, Nemirovsky NE, Gass JT, Olive MF. mGluR5 Positive and Negative Allosteric Modulators Differentially Affect Dendritic Spine Density and Morphology in the Prefrontal Cortex. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2016; 14:476-85. [PMID: 25921744 DOI: 10.2174/1871527314666150429112849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 01/17/2015] [Accepted: 01/19/2015] [Indexed: 12/31/2022]
Abstract
Positive and negative allosteric modulators (PAMs and NAMs, respectively) of type 5 metabotropic glutamate receptors (mGluR5) are currently being investigated as novel treatments for neuropsychiatric diseases including drug addiction, schizophrenia, and Fragile X syndrome. However, only a handful of studies have examined the effects of mGluR5 PAMs or NAMs on the structural plasticity of dendritic spines in otherwise naïve animals, particularly in brain regions mediating executive function. In the present study, we assessed dendritic spine density and morphology in pyramidal cells of the medial prefrontal cortex (mPFC) after repeated administration of either the prototypical mGluR5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5- yl)benzamide (CDPPB, 20 mg/kg), the clinically utilized mGluR5 NAM 1-(3-chlorophenyl)-3-(3-methyl-5-oxo-4Himidazol- 2-yl)urea (fenobam, 20 mg/kg), or vehicle in male Sprague-Dawley rats. Following once daily treatment for 10 consecutive days, coronal brain sections containing the mPFC underwent diolistic labeling and 3D image analysis of dendritic spines. Compared to vehicle treated animals, rats administered fenobam exhibited significant increases in dendritic spine density and the overall frequency of spines with small (<0.2 μm) head diameters, decreases in frequency of spines with medium (0.2-0.4 μm) head diameters, and had no changes in frequency of spines with large head diameters (>0.4 μm). Administration of CDPPB had no discernable effects on dendritic spine density or morphology, and neither CDPPB nor fenobam had any effect on spine length or volume. We conclude that mGluR5 PAMs and NAMs differentially affect mPFC dendritic spine structural plasticity in otherwise naïve animals, and additional studies assessing their effects in combination with cognitive or behavioral tasks are needed.
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Affiliation(s)
| | | | | | | | - Michael F Olive
- Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287, USA.
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364
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Abstract
There is increasing evidence that a deficiency in vitamin D contributes to many human diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), hypertension and cardiovascular disease. The ability of vitamin D to maintain healthy cells seems to depend on its role as a guardian of phenotypic stability particularly with regard to the reactive oxygen species (ROS) and Ca2+ signalling systems. Vitamin D maintains the expression of those signalling components responsible for stabilizing the low-resting state of these two signalling pathways. This vitamin D signalling stability hypothesis proposes that vitamin D, working in conjunction with klotho and Nrf2 (nuclear factor-erythroid-2-related factor 2), acts as a custodian to maintain the normal function of the ROS and Ca2+ signalling pathways. A decline in vitamin D levels will lead to an erosion of this signalling stability and may account for why so many of the major diseases in man, which have been linked to vitamin D deficiency, are associated with a dysregulation in both ROS and Ca2+ signalling.
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365
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Hoque A, Hossain MI, Ameen SS, Ang CS, Williamson N, Ng DCH, Chueh AC, Roulston C, Cheng HC. A beacon of hope in stroke therapy-Blockade of pathologically activated cellular events in excitotoxic neuronal death as potential neuroprotective strategies. Pharmacol Ther 2016; 160:159-79. [PMID: 26899498 DOI: 10.1016/j.pharmthera.2016.02.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Excitotoxicity, a pathological process caused by over-stimulation of ionotropic glutamate receptors, is a major cause of neuronal loss in acute and chronic neurological conditions such as ischaemic stroke, Alzheimer's and Huntington's diseases. Effective neuroprotective drugs to reduce excitotoxic neuronal loss in patients suffering from these neurological conditions are urgently needed. One avenue to achieve this goal is to clearly define the intracellular events mediating the neurotoxic signals originating from the over-stimulated glutamate receptors in neurons. In this review, we first focus on the key cellular events directing neuronal death but not involved in normal physiological processes in the neurotoxic signalling pathways. These events, referred to as pathologically activated events, are potential targets for the development of neuroprotectant therapeutics. Inhibitors blocking some of the known pathologically activated cellular events have been proven to be effective in reducing stroke-induced brain damage in animal models. Notable examples are inhibitors suppressing the ion channel activity of neurotoxic glutamate receptors and those disrupting interactions of specific cellular proteins occurring only in neurons undergoing excitotoxic cell death. Among them, Tat-NR2B9c and memantine are clinically effective in reducing brain damage caused by some acute and chronic neurological conditions. Our second focus is evaluation of the suitability of the other inhibitors for use as neuroprotective therapeutics. We also discuss the experimental approaches suitable for bridging our knowledge gap in our current understanding of the excitotoxic signalling mechanism in neurons and discovery of new pathologically activated cellular events as potential targets for neuroprotection.
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Affiliation(s)
- Ashfaqul Hoque
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - M Iqbal Hossain
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - S Sadia Ameen
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Ching-Seng Ang
- Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | | | - Dominic C H Ng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia; School of Biomedical Science, University of Queensland, St. Lucia, QLD, Australia
| | - Anderly C Chueh
- ACRF Chemical Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Carli Roulston
- Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, VIC 3065, Australia
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia.
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366
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Repression of the eIF2α kinase PERK alleviates mGluR-LTD impairments in a mouse model of Alzheimer's disease. Neurobiol Aging 2016; 41:19-24. [PMID: 27103515 DOI: 10.1016/j.neurobiolaging.2016.02.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/13/2016] [Accepted: 02/05/2016] [Indexed: 12/30/2022]
Abstract
Mounting evidence indicates that impairments of synaptic efficacy and/or plasticity may be a key step in the development of Alzheimer's disease (AD) pathophysiology. Among the 2 major forms of synaptic plasticity, long-term potentiation and long-term depression (LTD), much less is known about how LTD is regulated in AD and its molecular mechanisms. Recent studies indicate that metabotropic glutamate receptor 5 (mGluR5) may function as a receptor and/or co-receptor for amyloid beta. Herein, we examined mGluR-LTD in hippocampal slices from aged APP/PS1 mutant mice that model AD. Our findings demonstrate that mGluR-LTD is blocked in APP/PS1 mice, and that the mGluR-LTD failure is reversed by either genetically or pharmacologically suppressing the activity of PERK, a kinase for the mRNA translation factor eIF2α. These data are congruent with recent evidence that inhibition of eIF2α phosphorylation via PERK suppression and reversal of de novo protein synthesis deficits can mitigate cognitive deficits in neurodegenerative diseases. Together with reports indicating that mGluR5 may mediate amyloid beta synaptotoxicity, our findings offer insights into novel therapeutic targets for AD and other cognitive syndromes.
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367
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Sempou E, Biasini E, Pinzón-Olejua A, Harris DA, Málaga-Trillo E. Activation of zebrafish Src family kinases by the prion protein is an amyloid-β-sensitive signal that prevents the endocytosis and degradation of E-cadherin/β-catenin complexes in vivo. Mol Neurodegener 2016; 11:18. [PMID: 26860872 PMCID: PMC4748561 DOI: 10.1186/s13024-016-0076-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/18/2016] [Indexed: 11/25/2022] Open
Abstract
Background Prions and amyloid-β (Aβ) oligomers trigger neurodegeneration by hijacking a poorly understood cellular signal mediated by the prion protein (PrP) at the plasma membrane. In early zebrafish embryos, PrP-1-dependent signals control cell-cell adhesion via a tyrosine phosphorylation-dependent mechanism. Results Here we report that the Src family kinases (SFKs) Fyn and Yes act downstream of PrP-1 to prevent the endocytosis and degradation of E-cadherin/β-catenin adhesion complexes in vivo. Accordingly, knockdown of PrP-1 or Fyn/Yes cause similar zebrafish gastrulation phenotypes, whereas Fyn/Yes expression rescues the PrP-1 knockdown phenotype. We also show that zebrafish and mouse PrPs positively regulate the activity of Src kinases and that these have an unexpected positive effect on E-cadherin-mediated cell adhesion. Interestingly, while PrP knockdown impairs β-catenin adhesive function, PrP overexpression enhances it, thereby antagonizing its nuclear, wnt-related signaling activity and disturbing embryonic dorsoventral specification. The ability of mouse PrP to influence these events in zebrafish embryos requires its neuroprotective, polybasic N-terminus but not its neurotoxicity-associated central region. Remarkably, human Aβ oligomers up-regulate the PrP-1/SFK/E-cadherin/β-catenin pathway in zebrafish embryonic cells, mimicking a PrP gain-of-function scenario. Conclusions Our gain- and loss-of-function experiments in zebrafish suggest that PrP and SFKs enhance the cell surface stability of embryonic adherens junctions via the same complex mechanism through which they over-activate neuroreceptors that trigger synaptic damage. The profound impact of this pathway on early zebrafish development makes these embryos an ideal model to study the cellular and molecular events affected by neurotoxic PrP mutations and ligands in vivo. In particular, our finding that human Aβ oligomers activate the zebrafish PrP/SFK/E-cadherin pathway opens the possibility of using fish embryos to rapidly screen for novel therapeutic targets and compounds against prion- and Alzheimer's-related neurodegeneration. Altogether, our data illustrate PrP-dependent signals relevant to embryonic development, neuronal physiology and neurological disease. Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0076-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emily Sempou
- Department of Biology, University of Konstanz, Constance, 78457, Germany. .,Present address: Department of Pediatrics, Yale University School of Medicine, New Haven, CT, 06520, USA.
| | - Emiliano Biasini
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA. .,Present address: Dulbecco Telethon Institute, Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy.
| | - Alejandro Pinzón-Olejua
- Department of Biology, University of Konstanz, Constance, 78457, Germany. .,Present address: Max PIanck Institute for Brain Research, Department of Synaptic Plasticity, 60438, Frankfurt/Main, Germany.
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA.
| | - Edward Málaga-Trillo
- Department of Biology, University of Konstanz, Constance, 78457, Germany. .,Department of Biology, Universidad Peruana Cayetano Heredia, Lima 31, Perú.
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368
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Korsak LIT, Mitchell ME, Shepard KA, Akins MR. Regulation of neuronal gene expression by local axonal translation. CURRENT GENETIC MEDICINE REPORTS 2016; 4:16-25. [PMID: 27722035 DOI: 10.1007/s40142-016-0085-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
RNA localization is a key mechanism in the regulation of protein expression. In neurons, this includes the axonal transport of select mRNAs based on the recognition of axonal localization motifs in these RNAs by RNA binding proteins. Bioinformatic analyses of axonal RNAs suggest that selective inclusion of such localization motifs in mature mRNAs is one mechanism controlling the composition of the axonal transcriptome. The subsequent translation of axonal transcripts in response to specific stimuli provides precise spatiotemporal control of the axonal proteome. This axonal translation supports local phenomena including axon pathfinding, mitochondrial function, and synapse-specific plasticity. Axonal protein synthesis also provides transport machinery and signals for retrograde trafficking to the cell body to effect somatic changes including altering the transcriptional program. Here we review the remarkable progress made in recent years to identify and characterize these phenomena.
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Affiliation(s)
- Lulu I T Korsak
- Drexel University, PISB 312; 3245 Chestnut St, Philadelphia, PA 19104,
| | - Molly E Mitchell
- Drexel University, PISB 312; 3245 Chestnut St, Philadelphia, PA 19104,
| | | | - Michael R Akins
- Assistant Professor, Department of Biology, Department of Neurobiology & Anatomy, Drexel University, PISB 319; 3245 Chestnut St, Philadelphia, PA 19104,
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369
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APP Receptor? To Be or Not To Be. Trends Pharmacol Sci 2016; 37:390-411. [PMID: 26837733 DOI: 10.1016/j.tips.2016.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) and its metabolites play a key role in Alzheimer's disease pathogenesis. The idea that APP may function as a receptor has gained momentum based on its structural similarities to type I transmembrane receptors and the identification of putative APP ligands. We review the recent experimental evidence in support of this notion and discuss how this concept is viewed in the field. Specifically, we focus on the structural and functional characteristics of APP as a cell surface receptor, and on its interaction with adaptors and signaling proteins. We also address the importance of APP function as a receptor in Alzheimer's disease etiology and discuss how this function might be potentially important for the development of novel therapeutic approaches.
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370
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Sandoval-Hernández AG, Buitrago L, Moreno H, Cardona-Gómez GP, Arboleda G. Role of Liver X Receptor in AD Pathophysiology. PLoS One 2015; 10:e0145467. [PMID: 26720273 PMCID: PMC4697813 DOI: 10.1371/journal.pone.0145467] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 12/03/2015] [Indexed: 12/01/2022] Open
Abstract
Alzheimer's disease (AD) is the major cause of dementia worldwide. The pharmacological activation of nuclear receptors (Liver X receptors: LXRs or Retinoid X receptors: RXR) has been shown to induce overexpression of the ATP-Binding Cassette A1 (ABCA1) and Apolipoprotein E (ApoE), changes that are associated with improvement in cognition and reduction of amyloid beta pathology in amyloidogenic AD mouse models (i.e. APP, PS1: 2tg-AD). Here we investigated whether treatment with a specific LXR agonist has a measurable impact on the cognitive impairment in an amyloid and Tau AD mouse model (3xTg-AD: 12-months-old; three months treatment). The data suggests that the LXR agonist GW3965 is associated with increased expression of ApoE and ABCA1 in the hippocampus and cerebral cortex without a detectable reduction of the amyloid load. We also report that most cells overexpressing ApoE (86±12%) are neurons localized in the granular cell layer of the hippocampus and entorhinal cortex. In the GW3965 treated 3xTg-AD mice we also observed reduction in astrogliosis and increased number of stem and proliferating cells in the subgranular zone of the dentate gyrus. Additionally, we show that GW3965 rescued hippocampus long term synaptic plasticity, which had been disrupted by oligomeric amyloid beta peptides. The effect of GW3965 on synaptic function was protein synthesis dependent. Our findings identify alternative functional/molecular mechanisms by which LXR agonists may exert their potential benefits as a therapeutic strategy against AD.
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Affiliation(s)
| | - Luna Buitrago
- Departments of Neurology and Physiology/Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, SUNY Downstate Medical Center, Brooklyn, New York, United States of America
| | - Herman Moreno
- Departments of Neurology and Physiology/Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, SUNY Downstate Medical Center, Brooklyn, New York, United States of America
| | - Gloria Patricia Cardona-Gómez
- Área de Neurobiología Celular y Molecular, Grupo de Neurociencias de Antioquia, Universidad de Antioquia, Calle 70, No. 52–21, Medellín, Colombia
| | - Gonzalo Arboleda
- Grupo de Muerte Celular, Instituto de Genética Universidad Nacional de Colombia, Bogotá, Colombia
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371
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Jarosz-Griffiths HH, Noble E, Rushworth JV, Hooper NM. Amyloid-β Receptors: The Good, the Bad, and the Prion Protein. J Biol Chem 2015; 291:3174-83. [PMID: 26719327 PMCID: PMC4751366 DOI: 10.1074/jbc.r115.702704] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several different receptor proteins have been identified that bind monomeric, oligomeric, or fibrillar forms of amyloid-β (Aβ). "Good" receptors internalize Aβ or promote its transcytosis out of the brain, whereas "bad" receptors bind oligomeric forms of Aβ that are largely responsible for the synapticloss, memory impairments, and neurotoxicity that underlie Alzheimer disease. The prion protein both removes Aβ from the brain and transduces the toxic actions of Aβ. The clustering of distinct receptors in cell surface signaling platforms likely underlies the actions of distinct oligomeric species of Aβ. These Aβ receptor-signaling platforms provide opportunities for therapeutic intervention in Alzheimer disease.
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Affiliation(s)
- Heledd H Jarosz-Griffiths
- From the Institute of Brain, Behaviour and Mental Health, Faculty of Medical and Human Sciences, University of Manchester, Manchester M13 9PT and
| | - Elizabeth Noble
- From the Institute of Brain, Behaviour and Mental Health, Faculty of Medical and Human Sciences, University of Manchester, Manchester M13 9PT and
| | - Jo V Rushworth
- the Faculty of Health and Life Sciences, De Montfort University, Leicester LE1 9BH, United Kingdom
| | - Nigel M Hooper
- From the Institute of Brain, Behaviour and Mental Health, Faculty of Medical and Human Sciences, University of Manchester, Manchester M13 9PT and
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372
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Pallo SP, DiMaio J, Cook A, Nilsson B, Johnson GVW. Mechanisms of tau and Aβ-induced excitotoxicity. Brain Res 2015; 1634:119-131. [PMID: 26731336 DOI: 10.1016/j.brainres.2015.12.048] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/09/2015] [Accepted: 12/17/2015] [Indexed: 11/18/2022]
Abstract
Excitotoxicity was originally postulated to be a late stage side effect of Alzheimer׳s disease (AD)-related neurodegeneration, however more recent studies indicate that it may occur early in AD and contribute to the neurodegenerative process. Tau and amyloid beta (Aβ), the main components of neurofibrillary tangles (NFTs) and amyloid plaques, have been implicated in cooperatively and independently facilitating excitotoxicity. Our study investigated the roles of tau and Aβ in AD-related excitotoxicity. In vivo studies showed that tau knockout (tau(-/-)) mice were significantly protected from seizures and hippocampal superoxide production induced with the glutamate analog, kainic acid (KA). We hypothesized that tau accomplished this by facilitating KA-induced Ca(2+) influx into neurons, however lentiviral tau knockdown failed to ameliorate KA-induced Ca(2+) influx into primary rat cortical neurons. We further investigated if tau cooperated with Aβ to facilitate KA-induced Ca(2+) influx. While Aβ biphasically modulated the KA-induced Cacyt(2+) responses, tau knockdown continued to have no effect. Therefore, tau facilitates KA-induced seizures and superoxide production in a manner that does not involve facilitation of Ca(2+) influx through KA receptors (KAR). On the other hand, acute pretreatment with Aβ (10 min) enhanced KA-induced Ca(2+) influx, while chronic Aβ (24 h) significantly reduced it, regardless of tau knockdown. Given previously published connections between Aβ, group 1 metabotropic glutamate receptors (mGluRs), and KAR regulation, we hypothesized that Aβ modulates KAR via a G-protein coupled receptor pathway mediated by group 1 mGluRs. We found that Aβ did not activate group 1 mGluRs and inhibition of these receptors did not reverse Aβ modulation of KA-induced Ca(2+) influx. Therefore, Aβ biphasically regulates KAR via a mechanism that does not involve group 1mGluR activation.
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Affiliation(s)
- Susanne P Pallo
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY, USA.
| | - John DiMaio
- Department of Chemistry, University of Rochester, Rochester, NY, USA.
| | - Alexis Cook
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY, USA.
| | - Bradley Nilsson
- Department of Chemistry, University of Rochester, Rochester, NY, USA.
| | - Gail V W Johnson
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY, USA.
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373
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Neuronal Store-Operated Calcium Entry and Mushroom Spine Loss in Amyloid Precursor Protein Knock-In Mouse Model of Alzheimer's Disease. J Neurosci 2015; 35:13275-86. [PMID: 26424877 DOI: 10.1523/jneurosci.1034-15.2015] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease (AD) is the most common reason for elderly dementia in the world. We proposed that memory loss in AD is related to destabilization of mushroom postsynaptic spines involved in long-term memory storage. We demonstrated previously that stromal interaction molecule 2 (STIM2)-regulated neuronal store-operated calcium entry (nSOC) in postsynaptic spines play a key role in stability of mushroom spines by maintaining activity of synaptic Ca(2+)/calmodulin kinase II (CaMKII). Furthermore, we demonstrated previously that the STIM2-nSOC-CaMKII pathway is downregulated in presenilin 1 M146V knock-in (PS1-M146V KI) mouse model of AD, leading to loss of hippocampal mushroom spines in this model. In the present study, we demonstrate that hippocampal mushroom postsynaptic spines are also lost in amyloid precursor protein knock-in (APPKI) mouse model of AD. We demonstrated that loss of mushroom spines occurs as a result of accumulation of extracellular β-amyloid 42 in APPKI culture media. Our results indicate that extracellular Aβ42 acts by overactivating mGluR5 receptor in APPKI neurons, leading to elevated Ca(2+) levels in endoplasmic reticulum, compensatory downregulation of STIM2 expression, impaired synaptic nSOC, and reduced CaMKII activity. Pharmacological inhibition of mGluR5 or overexpression of STIM2 rescued synaptic nSOC and prevented mushroom spine loss in APPKI hippocampal neurons. Our results indicate that downregulation of synaptic STIM2-nSOC-CaMKII pathway causes loss of mushroom synaptic spines in both presenilin and APPKI mouse models of AD. We propose that modulators/activators of this pathway may have a potential therapeutic value for treatment of memory loss in AD. Significance statement: A direct connection between amyloid-induced synaptic mushroom spine loss and neuronal store-operated calcium entry pathway is shown. These results provide strong support for the calcium hypothesis of neurodegeneration and further validate the synaptic store-operated calcium entry pathway as a potential therapeutic target for Alzheimer's disease.
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374
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Haas LT, Salazar SV, Kostylev MA, Um JW, Kaufman AC, Strittmatter SM. Metabotropic glutamate receptor 5 couples cellular prion protein to intracellular signalling in Alzheimer's disease. Brain 2015; 139:526-46. [PMID: 26667279 DOI: 10.1093/brain/awv356] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 10/17/2015] [Indexed: 01/27/2023] Open
Abstract
Alzheimer's disease-related phenotypes in mice can be rescued by blockade of either cellular prion protein or metabotropic glutamate receptor 5. We sought genetic and biochemical evidence that these proteins function cooperatively as an obligate complex in the brain. We show that cellular prion protein associates via transmembrane metabotropic glutamate receptor 5 with the intracellular protein mediators Homer1b/c, calcium/calmodulin-dependent protein kinase II, and the Alzheimer's disease risk gene product protein tyrosine kinase 2 beta. Coupling of cellular prion protein to these intracellular proteins is modified by soluble amyloid-β oligomers, by mouse brain Alzheimer's disease transgenes or by human Alzheimer's disease pathology. Amyloid-β oligomer-triggered phosphorylation of intracellular protein mediators and impairment of synaptic plasticity in vitro requires Prnp-Grm5 genetic interaction, being absent in transheterozygous loss-of-function, but present in either single heterozygote. Importantly, genetic coupling between Prnp and Grm5 is also responsible for signalling, for survival and for synapse loss in Alzheimer's disease transgenic model mice. Thus, the interaction between metabotropic glutamate receptor 5 and cellular prion protein has a central role in Alzheimer's disease pathogenesis, and the complex is a potential target for disease-modifying intervention.
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Affiliation(s)
- Laura T Haas
- 1 Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, CT 06536, USA 2 Graduate School of Cellular and Molecular Neuroscience, University of Tuebingen, D-72074 Tuebingen, Germany
| | - Santiago V Salazar
- 1 Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Mikhail A Kostylev
- 1 Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Ji Won Um
- 1 Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Adam C Kaufman
- 1 Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Stephen M Strittmatter
- 1 Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, CT 06536, USA
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375
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Calamai M, Evangelisti E, Cascella R, Parenti N, Cecchi C, Stefani M, Pavone F. Single molecule experiments emphasize GM1 as a key player of the different cytotoxicity of structurally distinct Aβ1-42 oligomers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:386-92. [PMID: 26656159 DOI: 10.1016/j.bbamem.2015.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 11/10/2015] [Accepted: 12/03/2015] [Indexed: 12/29/2022]
Abstract
It is well established that cytotoxic Aβ oligomers are the key factor that triggers the initial tissue and cell modifications eventually culminating in the development of Alzheimer's disease. Aβ1-42 oligomers display a high degree of polymorphism, and several structurally different oligomers have been described. Amongst them, two types, recently classified as A+ and A-, have been shown to possess similar size but distinct toxic properties, as a consequence of their biophysical and structural differences. Here, we have investigated by means of single molecule tracking the oligomer mobility on the plasma membrane of living neuroblastoma cells and the interaction with the ganglioside GM1, a component of membrane rafts. We have found that A+ and A- oligomers display a similar lateral diffusion on the plasma membrane of living cells. However, only the toxic A+ oligomers appear to interact and alter the mobility of GM1. We have also studied the lateral diffusion of each kind of oligomers in cells depleted or enriched in GM1. We found that the content of GM1 influences the diffusion of both types of oligomer, although the effect of the increased levels of GM1 is higher for the A+ type. Interestingly, the content of GM1 also affects significantly the mobility of GM1 molecules themselves.
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Affiliation(s)
- Martino Calamai
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019 Florence, Italy; National Institute of Optics, National Research Council of Italy (CNR), Largo Fermi 6, 50125, Florence, Italy.
| | - Elisa Evangelisti
- Dipartimento di Scienze Biomediche Sperimentali e Clinche "Mario Serio", Università degli Studi di Firenze, 50134 Florence, Italy
| | - Roberta Cascella
- Dipartimento di Scienze Biomediche Sperimentali e Clinche "Mario Serio", Università degli Studi di Firenze, 50134 Florence, Italy
| | - Niccoló Parenti
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019 Florence, Italy
| | - Cristina Cecchi
- Dipartimento di Scienze Biomediche Sperimentali e Clinche "Mario Serio", Università degli Studi di Firenze, 50134 Florence, Italy; Centro Interuniversitario per lo Studio delle Malattie Neurodegenerative (CIMN), 50134 Florence, Italy
| | - Massimo Stefani
- Dipartimento di Scienze Biomediche Sperimentali e Clinche "Mario Serio", Università degli Studi di Firenze, 50134 Florence, Italy; Centro Interuniversitario per lo Studio delle Malattie Neurodegenerative (CIMN), 50134 Florence, Italy
| | - Francesco Pavone
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, 50019 Florence, Italy
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376
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DeLorenzo C, Sovago J, Gardus J, Xu J, Yang J, Behrje R, Kumar JSD, Devanand DP, Pelton GH, Mathis CA, Mason NS, Gomez-Mancilla B, Aizenstein H, Mann JJ, Parsey RV. Characterization of brain mGluR5 binding in a pilot study of late-life major depressive disorder using positron emission tomography and [¹¹C]ABP688. Transl Psychiatry 2015; 5:e693. [PMID: 26645628 PMCID: PMC5068588 DOI: 10.1038/tp.2015.189] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/05/2015] [Accepted: 10/26/2015] [Indexed: 01/06/2023] Open
Abstract
The metabotropic glutamate receptor subtype 5 (mGluR5) has been implicated in the pathophysiology of mood and anxiety disorders and is a potential treatment target in major depressive disorder (MDD). This study compared brain mGluR5 binding in elderly patients suffering from MDD with that in elderly healthy volunteers using positron emission tomography (PET) and [(11)C]ABP688. Twenty elderly (mean age: 63.0 ± 6.3) subjects with MDD and twenty-two healthy volunteers in the same age range (mean age: 66.4 ± 7.3) were examined with PET after a single bolus injection of [(11)C]ABP688, with many receiving arterial sampling. PET images were analyzed on a region of interest and a voxel level to compare mGluR5 binding in the brain between the two groups. Differences in [(11)C]ABP688 binding between patients with early- and late-onset depression were also assessed. In contrast to a previously published report in a younger cohort, no significant difference in [(11)C]ABP688 binding was observed between elderly subjects with MDD and healthy volunteers. [(11)C]ABP688 binding was also similar between subgroups with early- or late-onset depression. We believe this is the first study to examine mGluR5 expression in depression in the elderly. Although future work is required, results suggest potential differences in the pathophysiology of elderly depression versus depression earlier in life.
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Affiliation(s)
- C DeLorenzo
- Department of Psychiatry, Columbia University, New York, NY, USA,Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA,Department of Psychiatry, Stony Brook University, HSC-T-10, Room 40D, Stony Brook, NY 11794, USA. E-mail:
| | - J Sovago
- Novartis Institute for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - J Gardus
- Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA
| | - J Xu
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
| | - J Yang
- Department of Preventive Medicine, Stony Brook University, Stony Brook, NY, USA
| | - R Behrje
- Novartis Pharmaceuticals Corporations, East Hanover, NJ, USA
| | - J S D Kumar
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - D P Devanand
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - G H Pelton
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - C A Mathis
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - N S Mason
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - B Gomez-Mancilla
- Novartis Institute for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - H Aizenstein
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - J J Mann
- Department of Psychiatry, Columbia University, New York, NY, USA
| | - R V Parsey
- Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA
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377
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Miyamoto T, Kim D, Knox JA, Johnson E, Mucke L. Increasing the Receptor Tyrosine Kinase EphB2 Prevents Amyloid-β-induced Depletion of Cell Surface Glutamate Receptors by a Mechanism That Requires the PDZ-binding Motif of EphB2 and Neuronal Activity. J Biol Chem 2015; 291:1719-1734. [PMID: 26589795 PMCID: PMC4722453 DOI: 10.1074/jbc.m115.666529] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 11/11/2022] Open
Abstract
Diverse lines of evidence suggest that amyloid-β (Aβ) peptides causally contribute to the pathogenesis of Alzheimer disease (AD), the most frequent neurodegenerative disorder. However, the mechanisms by which Aβ impairs neuronal functions remain to be fully elucidated. Previous studies showed that soluble Aβ oligomers interfere with synaptic functions by depleting NMDA-type glutamate receptors (NMDARs) from the neuronal surface and that overexpression of the receptor tyrosine kinase EphB2 can counteract this process. Through pharmacological treatments and biochemical analyses of primary neuronal cultures expressing wild-type or mutant forms of EphB2, we demonstrate that this protective effect of EphB2 depends on its PDZ-binding motif and the presence of neuronal activity but not on its kinase activity. We further present evidence that the protective effect of EphB2 may be mediated by the AMPA-type glutamate receptor subunit GluA2, which can become associated with the PDZ-binding motif of EphB2 through PDZ domain-containing proteins and can promote the retention of NMDARs in the membrane. In addition, we show that the Aβ-induced depletion of surface NMDARs does not depend on several factors that have been implicated in the pathogenesis of Aβ-induced neuronal dysfunction, including aberrant neuronal activity, tau, prion protein (PrPC), and EphB2 itself. Thus, although EphB2 does not appear to be directly involved in the Aβ-induced depletion of NMDARs, increasing its expression may counteract this pathogenic process through a neuronal activity- and PDZ-dependent regulation of AMPA-type glutamate receptors.
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Affiliation(s)
- Takashi Miyamoto
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and; Department of Neurology, University of California, San Francisco, California 94158
| | - Daniel Kim
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and
| | - Joseph A Knox
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and
| | - Erik Johnson
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and; Department of Neurology, University of California, San Francisco, California 94158
| | - Lennart Mucke
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and; Department of Neurology, University of California, San Francisco, California 94158.
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378
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De Mario A, Castellani A, Peggion C, Massimino ML, Lim D, Hill AF, Sorgato MC, Bertoli A. The prion protein constitutively controls neuronal store-operated Ca(2+) entry through Fyn kinase. Front Cell Neurosci 2015; 9:416. [PMID: 26578881 PMCID: PMC4623396 DOI: 10.3389/fncel.2015.00416] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/02/2015] [Indexed: 11/23/2022] Open
Abstract
The prion protein (PrPC) is a cell surface glycoprotein mainly expressed in neurons, whose misfolded isoforms generate the prion responsible for incurable neurodegenerative disorders. Whereas PrPC involvement in prion propagation is well established, PrPC physiological function is still enigmatic despite suggestions that it could act in cell signal transduction by modulating phosphorylation cascades and Ca2+ homeostasis. Because PrPC binds neurotoxic protein aggregates with high-affinity, it has also been proposed that PrPC acts as receptor for amyloid-β (Aβ) oligomers associated with Alzheimer’s disease (AD), and that PrPC-Aβ binding mediates AD-related synaptic dysfunctions following activation of the tyrosine kinase Fyn. Here, use of gene-encoded Ca2+ probes targeting different cell domains in primary cerebellar granule neurons (CGN) expressing, or not, PrPC, allowed us to investigate whether PrPC regulates store-operated Ca2+ entry (SOCE) and the implication of Fyn in this control. Our findings show that PrPC attenuates SOCE, and Ca2+ accumulation in the cytosol and mitochondria, by constitutively restraining Fyn activation and tyrosine phosphorylation of STIM1, a key molecular component of SOCE. This data establishes the existence of a PrPC-Fyn-SOCE triad in neurons. We also demonstrate that treating cerebellar granule and cortical neurons with soluble Aβ(1–42) oligomers abrogates the control of PrPC over Fyn and SOCE, suggesting a PrPC-dependent mechanizm for Aβ-induced neuronal Ca2+ dyshomeostasis.
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Affiliation(s)
- Agnese De Mario
- Department of Biomedical Science, University of Padova Padova, Italy
| | - Angela Castellani
- Department of Biomedical Science, University of Padova Padova, Italy
| | - Caterina Peggion
- Department of Biomedical Science, University of Padova Padova, Italy
| | | | - Dmitry Lim
- Department of Pharmaceutical Science, University of Piemonte Orientale Novara, Italy
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University Melbourne, VIC, Australia
| | - M Catia Sorgato
- Department of Biomedical Science, University of Padova Padova, Italy ; CNR Neuroscience Institute, University of Padova Padova, Italy
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379
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Dinamarca MC, Di Luca M, Godoy JA, Inestrosa NC. The soluble extracellular fragment of neuroligin-1 targets Aβ oligomers to the postsynaptic region of excitatory synapses. Biochem Biophys Res Commun 2015; 466:66-71. [DOI: 10.1016/j.bbrc.2015.08.107] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 08/24/2015] [Indexed: 11/30/2022]
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380
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Arnsten AFT. Stress weakens prefrontal networks: molecular insults to higher cognition. Nat Neurosci 2015; 18:1376-85. [PMID: 26404712 DOI: 10.1038/nn.4087] [Citation(s) in RCA: 468] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/15/2015] [Indexed: 12/13/2022]
Abstract
A variety of cognitive disorders are worsened by stress exposure and involve dysfunction of the newly evolved prefrontal cortex (PFC). Exposure to acute, uncontrollable stress increases catecholamine release in PFC, reducing neuronal firing and impairing cognitive abilities. High levels of noradrenergic α1-adrenoceptor and dopaminergic D1 receptor stimulation activate feedforward calcium-protein kinase C and cyclic AMP-protein kinase A signaling, which open potassium channels to weaken synaptic efficacy in spines. In contrast, high levels of catecholamines strengthen the primary sensory cortices, amygdala and striatum, rapidly flipping the brain from reflective to reflexive control of behavior. These mechanisms are exaggerated by chronic stress exposure, where architectural changes lead to persistent loss of PFC function. Understanding these mechanisms has led to the successful translation of prazosin and guanfacine for treating stress-related disorders. Dysregulation of stress signaling pathways by genetic insults likely contributes to PFC deficits in schizophrenia, while age-related insults initiate interacting vicious cycles that increase vulnerability to Alzheimer's degeneration.
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Affiliation(s)
- Amy F T Arnsten
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut, USA
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381
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Wang W, Mandel J, Bouaziz J, Commenges D, Nabirotchkine S, Chumakov I, Cohen D, Guedj M, the Alzheimer’s Disease Neuroimaging Initiative. A Multi-Marker Genetic Association Test Based on the Rasch Model Applied to Alzheimer's Disease. PLoS One 2015; 10:e0138223. [PMID: 26379234 PMCID: PMC4574966 DOI: 10.1371/journal.pone.0138223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/27/2015] [Indexed: 12/28/2022] Open
Abstract
Results from Genome-Wide Association Studies (GWAS) have shown that the genetic basis of complex traits often include many genetic variants with small to moderate effects whose identification remains a challenging problem. In this context multi-marker analysis at the gene and pathway level can complement traditional point-wise approaches that treat the genetic markers individually. In this paper we propose a novel statistical approach for multi-marker analysis based on the Rasch model. The method summarizes the categorical genotypes of SNPs by a generalized logistic function into a genetic score that can be used for association analysis. Through different sets of simulations, the false-positive rate and power of the proposed approach are compared to a set of existing methods, and shows good performances. The application of the Rasch model on Alzheimer's Disease (AD) ADNI GWAS dataset also allows a coherent interpretation of the results. Our analysis supports the idea that APOE is a major susceptibility gene for AD. In the top genes selected by proposed method, several could be functionally linked to AD. In particular, a pathway analysis of these genes also highlights the metabolism of cholesterol, that is known to play a key role in AD pathogenesis. Interestingly, many of these top genes can be integrated in a hypothetic signalling network.
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Affiliation(s)
- Wenjia Wang
- Pharnext, Issy-les-Moulineaux, Ile de France, France
- Inserm U897, University of Bordeaux, Bordeaux, Aquitaine, France
| | - Jonas Mandel
- Pharnext, Issy-les-Moulineaux, Ile de France, France
| | - Jan Bouaziz
- Pharnext, Issy-les-Moulineaux, Ile de France, France
| | - Daniel Commenges
- Inserm U897, University of Bordeaux, Bordeaux, Aquitaine, France
| | | | - Ilya Chumakov
- Pharnext, Issy-les-Moulineaux, Ile de France, France
| | - Daniel Cohen
- Pharnext, Issy-les-Moulineaux, Ile de France, France
| | - Mickaël Guedj
- Pharnext, Issy-les-Moulineaux, Ile de France, France
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382
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Iraci N, Stincardini C, Barreca ML, Biasini E. Decoding the function of the N-terminal tail of the cellular prion protein to inspire novel therapeutic avenues for neurodegenerative diseases. Virus Res 2015; 207:62-8. [DOI: 10.1016/j.virusres.2014.10.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/18/2014] [Accepted: 10/14/2014] [Indexed: 01/13/2023]
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383
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Aggregation propensity of neuronal receptors: potential implications in neurodegenerative disorders. Future Sci OA 2015; 1:FSO39. [PMID: 28031868 PMCID: PMC5137917 DOI: 10.4155/fso.15.39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Misfolding and aggregation of proteins in tissues is linked to the onset of a diverse set of human neurodegenerative disorders, including Alzheimer's and Parkinson's diseases. In these pathologies proteins usually aggregate into highly ordered and β-sheet enriched amyloid fibrils. However, the formation of these toxic structures is not restricted to a reduced set of polypeptides but rather an intrinsic property of proteins. This suggests that the number of proteins involved in conformational disorders might be much larger than previously thought. The propensity of a protein to form amyloid assemblies is imprinted in its sequence and can be read using computational approaches. Here, we exploit four of these algorithms to analyze the presence of aggregation-prone regions in the sequence and structure of the extracellular domains of several neuroreceptors, with the idea of identifying patches that can interact anomalously with other aggregation-prone molecules such as the amyloid-β peptide or promote their self-assembly. The number of amyloidogenic regions in these domains is rather low but they are significantly exposed to solvent and therefore are suitable for interactions. We find a significant overlap between aggregation-prone regions and receptors interfaces and/or ligand-binding sites, which illustrates an unavoidable competition between the formation of functional native interactions and that of dangerous amyloid-like contacts leading to disease.
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384
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Popugaeva E, Pchitskaya E, Speshilova A, Alexandrov S, Zhang H, Vlasova O, Bezprozvanny I. STIM2 protects hippocampal mushroom spines from amyloid synaptotoxicity. Mol Neurodegener 2015; 10:37. [PMID: 26275606 PMCID: PMC4536802 DOI: 10.1186/s13024-015-0034-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/10/2015] [Indexed: 11/28/2022] Open
Abstract
Background Alzheimer disease (AD) is a disease of lost memories. Mushroom postsynaptic spines play a key role in memory storage, and loss of mushroom spines has been proposed to be linked to memory loss in AD. Generation of amyloidogenic peptides and accumulation of amyloid plaques is one of the pathological hallmarks of AD. It is important to evaluate effects of amyloid on stability of mushroom spines. Results In this study we used in vitro and in vivo models of amyloid synaptotoxicity to investigate effects of amyloid peptides on hippocampal mushroom spines. We discovered that application of Aβ42 oligomers to hippocampal cultures or injection of Aβ42 oligomers directly into hippocampal region resulted in reduction of mushroom spines and activity of synaptic calcium-calmodulin-dependent kinase II (CaMKII). We further discovered that expression of STIM2 protein rescued CaMKII activity and protected mushroom spines from amyloid toxicity in vitro and in vivo. Conclusions Obtained results suggest that downregulation of STIM2-dependent stability of mushroom spines and reduction in activity of synaptic CaMKII is a mechanism of hippocampal synaptic loss in AD model of amyloid synaptotoxicity and that modulators/activators of this pathway may have a potential therapeutic value for treatment of AD. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0034-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elena Popugaeva
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation.
| | - Ekaterina Pchitskaya
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation.
| | - Anastasiya Speshilova
- Laboratory of Microscopy and Microanalysis, Department of Physics-chemistry and Microsystem Technique, Institute of Metallurgy, Mechanical Engineering and Transport, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation.
| | - Sergey Alexandrov
- Laboratory of Microscopy and Microanalysis, Department of Physics-chemistry and Microsystem Technique, Institute of Metallurgy, Mechanical Engineering and Transport, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation.
| | - Hua Zhang
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX, 75390, USA.
| | - Olga Vlasova
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation.
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, Peter the Great St.Petersburg Polytechnic University, St. Petersburg, Russian Federation. .,Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX, 75390, USA.
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385
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Steinert JR. Prion protein as a mediator of synaptic transmission. Commun Integr Biol 2015; 8:e1063753. [PMID: 26478992 PMCID: PMC4594542 DOI: 10.1080/19420889.2015.1063753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 10/31/2022] Open
Abstract
Neurodegenerative disorders are characterized by synaptic and neuronal dysfunction which precedes general neuronal loss and subsequent cognitive or behavioral anomalies. Although the exact early cellular signaling mechanisms involved in neurodegenerative diseases are largely unknown, a view is emerging that compromised synaptic function may underlie the initial steps in disease progression. Much recent research has been aimed at understanding these early underlying processes leading to dysfunctional synaptic signaling, as this knowledge could identify putative sites of interventions, which could potentially slow progression and delay onset of disease. We have recently reported that synaptic function in a Drosophila melanogaster model can be modulated by the presence of native mouse prion protein and this modulation is negatively affected by a mutation within the protein which is associated with the Gerstmann-Sträussler-Scheinker syndrome, a human form of prion disease. Indeed, wild-type prion protein facilitates synaptic release, whereas the mutated form induced diminished phenotypes. It is believed that together with the gain-of-function of neurotoxic misfolded prion signaling, the lack of prion protein contributes to the pathology in prion diseases. Therefore, our study investigated a potential endogenous role of prion protein in synaptic signaling, the lack of which could resemble a lack-of-function phenotype in prion disease.
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386
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Berridge MJ. Vitamin D cell signalling in health and disease. Biochem Biophys Res Commun 2015; 460:53-71. [PMID: 25998734 DOI: 10.1016/j.bbrc.2015.01.008] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 01/05/2015] [Indexed: 12/13/2022]
Abstract
Vitamin D deficiency has been linked to many human diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), hypertension and cardiovascular disease. A Vitamin D phenotypic stability hypothesis, which is developed in this review, attempts to describe how this vital hormone acts to maintain healthy cellular functions. This role of Vitamin D as a guardian of phenotypic stability seems to depend on its ability to maintain the redox and Ca(2+) signalling systems. It is argued that its primary action is to maintain the expression of those signalling components responsible for stabilizing the low resting state of these two signalling pathways. This phenotypic stability role is facilitated through the ability of vitamin D to increase the expression of both Nrf2 and the anti-ageing protein Klotho, which are also major regulators of Ca(2+) and redox signalling. A decline in Vitamin D levels will lead to a decline in the stability of this regulatory signalling network and may account for why so many of the major diseases in man, which have been linked to vitamin D deficiency, are associated with a dysregulation in both ROS and Ca(2+) signalling.
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387
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Beckman D, Santos LE, Americo TA, Ledo JH, de Mello FG, Linden R. Prion Protein Modulates Monoaminergic Systems and Depressive-like Behavior in Mice. J Biol Chem 2015; 290:20488-98. [PMID: 26152722 DOI: 10.1074/jbc.m115.666156] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Indexed: 12/14/2022] Open
Abstract
We sought to examine interactions of the prion protein (PrP(C)) with monoaminergic systems due to: the role of PrP(C) in both Prion and Alzheimer diseases, which include clinical depression among their symptoms, the implication of monoamines in depression, and the hypothesis that PrP(C) serves as a scaffold for signaling systems. To that effect we compared both behavior and monoaminergic markers in wild type (WT) and PrP(C)-null (PrP(-/-)) mice. PrP(-/-) mice performed poorly when compared with WT in forced swimming, tail suspension, and novelty suppressed feeding tests, typical of depressive-like behavior, but not in the control open field nor rotarod motor tests; cyclic AMP responses to stimulation of D1 receptors by dopamine was selectively impaired in PrP(-/-) mice, and responses to serotonin, but not to norepinephrine, also differed between genotypes. Contents of dopamine, tyrosine hydroxylase, and the 5-HT5A serotonin receptor were increased in the cerebral cortex of PrP(-/-), as compared with WT mice. Microscopic colocalization, as well as binding in overlay assays were found of PrP(C) with both the 5HT5A and D1, but not D4 receptors. The data are consistent with the scaffolding of monoaminergic signaling modules by PrP(C), and may help understand the pathogenesis of clinical depression and neurodegenerative disorders.
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Affiliation(s)
| | | | | | - Jose H Ledo
- Instituto de Bioquímica Médica da UFRJ, Rio de Janeiro 21941-902, Brasil
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388
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Dorostkar MM, Zou C, Blazquez-Llorca L, Herms J. Analyzing dendritic spine pathology in Alzheimer's disease: problems and opportunities. Acta Neuropathol 2015; 130:1-19. [PMID: 26063233 PMCID: PMC4469300 DOI: 10.1007/s00401-015-1449-5] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/02/2015] [Accepted: 06/02/2015] [Indexed: 12/22/2022]
Abstract
Synaptic failure is an immediate cause of cognitive decline and memory dysfunction in Alzheimer’s disease. Dendritic spines are specialized structures on neuronal processes, on which excitatory synaptic contacts take place and the loss of dendritic spines directly correlates with the loss of synaptic function. Dendritic spines are readily accessible for both in vitro and in vivo experiments and have, therefore, been studied in great detail in Alzheimer’s disease mouse models. To date, a large number of different mechanisms have been proposed to cause dendritic spine dysfunction and loss in Alzheimer’s disease. For instance, amyloid beta fibrils, diffusible oligomers or the intracellular accumulation of amyloid beta have been found to alter the function and structure of dendritic spines by distinct mechanisms. Furthermore, tau hyperphosphorylation and microglia activation, which are thought to be consequences of amyloidosis in Alzheimer’s disease, may also contribute to spine loss. Lastly, genetic and therapeutic interventions employed to model the disease and elucidate its pathogenetic mechanisms in experimental animals may cause alterations of dendritic spines on their own. However, to date none of these mechanisms have been translated into successful therapeutic approaches for the human disease. Here, we critically review the most intensely studied mechanisms of spine loss in Alzheimer’s disease as well as the possible pitfalls inherent in the animal models of such a complex neurodegenerative disorder.
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Affiliation(s)
- Mario M. Dorostkar
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Chengyu Zou
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University Munich, Munich, Germany
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Lidia Blazquez-Llorca
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Jochen Herms
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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389
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Aimi T, Suzuki K, Hoshino T, Mizushima T. Dextran sulfate sodium inhibits amyloid-β oligomer binding to cellular prion protein. J Neurochem 2015; 134:611-7. [PMID: 25963375 DOI: 10.1111/jnc.13166] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/16/2015] [Accepted: 04/30/2015] [Indexed: 11/30/2022]
Abstract
Amyloid-β peptide (Aβ), especially its oligomeric form, is believed to play an important role in the pathogenesis of Alzheimer's disease (AD). To this end, the binding of Aβ oligomer to cellular prion protein (PrP(C)) plays an important role in synaptic dysfunction in a mouse model of AD. Here, we have screened for compounds that inhibit Aβ oligomer binding to PrP(C) from medicines already used clinically (Mizushima Approved Medicine Library 1), and identified dextran sulfate sodium (DSS) as a candidate. In a cell-free assay, DSS inhibited Aβ oligomer binding to PrP(C) but not to ephrin receptor B2, another endogenous receptor for Aβ oligomers, suggesting that the drug's action is specific to the binding of Aβ oligomer to PrP(C) . Dextran on the other hand did not affect this binding. DSS also suppressed Aβ oligomer binding to cells expressing PrP(C) but not to control cells. Furthermore, while incubation of mouse hippocampal slices with Aβ oligomers inhibited the induction of long-term potentiation, simultaneous treatment with DSS restored the long-term potentiation. As DSS has already been approved for use in patients with hypertriglyceridemia, and its safety in humans has been confirmed, we propose further analysis of this drug as a candidate for AD treatment. Amyloid-β peptide (Aβ) oligomer-binding to cellular prion protein (PrP(C) ) is important in synaptic dysfunction in Alzheimer's disease (AD). We found here that dextran sulfate sodium (DSS) inhibits Aβ oligomer binding to PrP(C) . Simultaneous treatment of hippocampal slices with DSS restored long-term potentiation (LTP) in the presence of Aβ oligomers. Since DSS has already been approved for clinical use, we propose this drug is a candidate drug for AD treatment.
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390
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Kumar A, Dhull DK, Mishra PS. Therapeutic potential of mGluR5 targeting in Alzheimer's disease. Front Neurosci 2015; 9:215. [PMID: 26106290 PMCID: PMC4460345 DOI: 10.3389/fnins.2015.00215] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/29/2015] [Indexed: 11/13/2022] Open
Abstract
Decades of research dedicated toward Alzheimer's disease (AD) has culminated in much of the current understanding of the neurodegeneration associated with disease. However, delineating the pathophysiology and finding a possible cure for the disease is still wanting. This is in part due to the lack of knowledge pertaining to the connecting link between neurodegenerative and neuroinflammatory pathways. Consequently, the inefficacy and ill-effects of the drugs currently available for AD encourage the need for alternative and safe therapeutic intervention. In this review we highlight the potential of mGluR5, a metabotropic glutamatergic receptor, in understanding the mechanism underlying the neuronal death and neuroinflammation in AD. We also discuss the role of mGlu5 receptor in mediating the neuron-glia interaction in the disease. Finally, we discuss the potential of mGluR5 as target for treating AD.
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Affiliation(s)
- Anil Kumar
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University Chandigarh, India
| | - Dinesh K Dhull
- UGC Centre of Advanced Studies, University Institute of Pharmaceutical Sciences, Panjab University Chandigarh, India
| | - Pooja S Mishra
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences Bangalore, India
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391
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Intracellular oligomeric amyloid-beta rapidly regulates GluA1 subunit of AMPA receptor in the hippocampus. Sci Rep 2015; 5:10934. [PMID: 26055072 PMCID: PMC4460729 DOI: 10.1038/srep10934] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/08/2015] [Indexed: 01/08/2023] Open
Abstract
The acute neurotoxicity of oligomeric forms of amyloid-β 1-42 (Aβ) is implicated in the pathogenesis of Alzheimer’s disease (AD). However, how these oligomers might first impair neuronal function at the onset of pathology is poorly understood. Here we have examined the underlying toxic effects caused by an increase in levels of intracellular Aβ, an event that could be important during the early stages of the disease. We show that oligomerised Aβ induces a rapid enhancement of AMPA receptor-mediated synaptic transmission (EPSCA) when applied intracellularly. This effect is dependent on postsynaptic Ca2+ and PKA. Knockdown of GluA1, but not GluA2, prevents the effect, as does expression of a S845-phosphomutant of GluA1. Significantly, an inhibitor of Ca2+-permeable AMPARs (CP-AMPARs), IEM 1460, reverses the increase in the amplitude of EPSCA. These results suggest that a primary neuronal response to intracellular Aβ oligomers is the rapid synaptic insertion of CP-AMPARs.
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392
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Kaufman AC, Salazar SV, Haas LT, Yang J, Kostylev MA, Jeng AT, Robinson SA, Gunther EC, van Dyck CH, Nygaard HB, Strittmatter SM. Fyn inhibition rescues established memory and synapse loss in Alzheimer mice. Ann Neurol 2015; 77:953-71. [PMID: 25707991 PMCID: PMC4447598 DOI: 10.1002/ana.24394] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/18/2015] [Accepted: 02/19/2015] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Currently no effective disease-modifying agents exist for the treatment of Alzheimer disease (AD). The Fyn tyrosine kinase is implicated in AD pathology triggered by amyloid-ß oligomers (Aßo) and propagated by Tau. Thus, Fyn inhibition may prevent or delay disease progression. Here, we sought to repurpose the Src family kinase inhibitor oncology compound, AZD0530, for AD. METHODS The pharmacokinetics and distribution of AZD0530 were evaluated in mice. Inhibition of Aßo signaling to Fyn, Pyk2, and Glu receptors by AZD0530 was tested by brain slice assays. After AZD0530 or vehicle treatment of wild-type and AD transgenic mice, memory was assessed by Morris water maze and novel object recognition. For these cohorts, amyloid precursor protein (APP) metabolism, synaptic markers (SV2 and PSD-95), and targets of Fyn (Pyk2 and Tau) were studied by immunohistochemistry and by immunoblotting. RESULTS AZD0530 potently inhibits Fyn and prevents both Aßo-induced Fyn signaling and downstream phosphorylation of the AD risk gene product Pyk2, and of NR2B Glu receptors in brain slices. After 4 weeks of treatment, AZD0530 dosing of APP/PS1 transgenic mice fully rescues spatial memory deficits and synaptic depletion, without altering APP or Aß metabolism. AZD0530 treatment also reduces microglial activation in APP/PS1 mice, and rescues Tau phosphorylation and deposition abnormalities in APP/PS1/Tau transgenic mice. There is no evidence of AZD0530 chronic toxicity. INTERPRETATION Targeting Fyn can reverse memory deficits found in AD mouse models, and rescue synapse density loss characteristic of the disease. Thus, AZD0530 is a promising candidate to test as a potential therapy for AD.
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Affiliation(s)
- Adam C. Kaufman
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Santiago V. Salazar
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Laura T. Haas
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Jinhee Yang
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Mikhail A. Kostylev
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Amanda T. Jeng
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Sophie A. Robinson
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
| | - Erik C. Gunther
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Haakon B. Nygaard
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Stephen M. Strittmatter
- Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
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393
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Kostylev MA, Kaufman AC, Nygaard HB, Patel P, Haas LT, Gunther EC, Vortmeyer A, Strittmatter SM. Prion-Protein-interacting Amyloid-β Oligomers of High Molecular Weight Are Tightly Correlated with Memory Impairment in Multiple Alzheimer Mouse Models. J Biol Chem 2015; 290:17415-38. [PMID: 26018073 DOI: 10.1074/jbc.m115.643577] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Indexed: 12/22/2022] Open
Abstract
Alzheimer disease (AD) is characterized by amyloid-β accumulation, with soluble oligomers (Aβo) being the most synaptotoxic. However, the multivalent and unstable nature of Aβo limits molecular characterization and hinders research reproducibility. Here, we characterized multiple Aβo forms throughout the life span of various AD mice and in post-mortem human brain. Aβo exists in several populations, where prion protein (PrP(C))-interacting Aβo is a high molecular weight Aβ assembly present in multiple mice and humans with AD. Levels of PrP(C)-interacting Aβo match closely with mouse memory and are equal or superior to other Aβ measures in predicting behavioral impairment. However, Aβo metrics vary considerably between mouse strains. Deleting PrP(C) expression in mice with relatively low PrP(C)-interacting Aβo (Tg2576) results in partial rescue of cognitive performance as opposed to complete recovery in animals with a high percentage of PrP(C)-interacting Aβo (APP/PSEN1). These findings highlight the relative contributions and interplay of Aβo forms in AD.
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Affiliation(s)
- Mikhail A Kostylev
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and
| | - Adam C Kaufman
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and
| | - Haakon B Nygaard
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and the Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Pujan Patel
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and
| | - Laura T Haas
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and
| | - Erik C Gunther
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and the Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Alexander Vortmeyer
- the Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06536 and
| | - Stephen M Strittmatter
- From the Program in Cellular Neuroscience, Neurodegeneration, and Repair and the Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06520
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394
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Ferreira ST, Lourenco MV, Oliveira MM, De Felice FG. Soluble amyloid-β oligomers as synaptotoxins leading to cognitive impairment in Alzheimer's disease. Front Cell Neurosci 2015; 9:191. [PMID: 26074767 PMCID: PMC4443025 DOI: 10.3389/fncel.2015.00191] [Citation(s) in RCA: 253] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 04/30/2015] [Indexed: 12/22/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia in the elderly, and affects millions of people worldwide. As the number of AD cases continues to increase in both developed and developing countries, finding therapies that effectively halt or reverse disease progression constitutes a major research and public health challenge. Since the identification of the amyloid-β peptide (Aβ) as the major component of the amyloid plaques that are characteristically found in AD brains, a major effort has aimed to determine whether and how Aβ leads to memory loss and cognitive impairment. A large body of evidence accumulated in the past 15 years supports a pivotal role of soluble Aβ oligomers (AβOs) in synapse failure and neuronal dysfunction in AD. Nonetheless, a number of basic questions, including the exact molecular composition of the synaptotoxic oligomers, the identity of the receptor(s) to which they bind, and the signaling pathways that ultimately lead to synapse failure, remain to be definitively answered. Here, we discuss recent advances that have illuminated our understanding of the chemical nature of the toxic species and the deleterious impact they have on synapses, and have culminated in the proposal of an Aβ oligomer hypothesis for Alzheimer’s pathogenesis. We also highlight outstanding questions and challenges in AD research that should be addressed to allow translation of research findings into effective AD therapies.
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Affiliation(s)
- Sergio T Ferreira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil ; Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Mauricio M Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
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395
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Risse E, Nicoll AJ, Taylor WA, Wright D, Badoni M, Yang X, Farrow MA, Collinge J. Identification of a Compound That Disrupts Binding of Amyloid-β to the Prion Protein Using a Novel Fluorescence-based Assay. J Biol Chem 2015; 290:17020-8. [PMID: 25995455 PMCID: PMC4505445 DOI: 10.1074/jbc.m115.637124] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Indexed: 11/20/2022] Open
Abstract
The prion protein (PrP) has been implicated both in prion diseases such as Creutzfeldt-Jakob disease, where its monomeric cellular isoform (PrPC) is recruited into pathogenic self-propagating polymers of misfolded protein, and in Alzheimer disease, where PrPC may act as a receptor for synaptotoxic oligomeric forms of amyloid-β (Aβ). There has been considerable interest in identification of compounds that bind to PrPC, stabilizing its native fold and thereby acting as pharmacological chaperones to block prion propagation and pathogenesis. However, compounds binding PrPC could also inhibit the binding of toxic Aβ species and may have a role in treating Alzheimer disease, a highly prevalent dementia for which there are currently no disease-modifying treatments. However, the absence of a unitary, readily measurable, physiological function of PrP makes screening for ligands challenging, and the highly heterogeneous nature of Aβ oligomer preparations makes conventional competition binding assays difficult to interpret. We have therefore developed a high-throughput screen that utilizes site-specifically fluorescently labeled protein to identify compounds that bind to PrP and inhibit both Aβ binding and prion propagation. Following a screen of 1,200 approved drugs, we identified Chicago Sky Blue 6B as the first small molecule PrP ligand capable of inhibiting Aβ binding, demonstrating the feasibility of development of drugs to block this interaction. The interaction of Chicago Sky Blue 6B was characterized by isothermal titration calorimetry, and its ability to inhibit Aβ binding and reduce prion levels was established in cell-based assays.
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Affiliation(s)
- Emmanuel Risse
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Andrew J Nicoll
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - William A Taylor
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Daniel Wright
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Mayank Badoni
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Xiaofan Yang
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Mark A Farrow
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
| | - John Collinge
- From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom
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396
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Liang J, Kulasiri D, Samarasinghe S. Ca2+ dysregulation in the endoplasmic reticulum related to Alzheimer's disease: A review on experimental progress and computational modeling. Biosystems 2015; 134:1-15. [PMID: 25998697 DOI: 10.1016/j.biosystems.2015.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/12/2015] [Accepted: 05/12/2015] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is a devastating, incurable neurodegenerative disease affecting millions of people worldwide. Dysregulation of intracellular Ca(2+) signaling has been observed as an early event prior to the presence of clinical symptoms of AD and is believed to be a crucial factor contributing to its pathogenesis. The progressive and sustaining increase in the resting level of cytosolic Ca(2+) will affect downstream activities and neural functions. This review focuses on the issues relating to the increasing Ca(2+) release from the endoplasmic reticulum (ER) observed in AD neurons. Numerous research papers have suggested that the dysregulation of ER Ca(2+) homeostasis is associated with mutations in the presenilin genes and amyloid-β oligomers. These disturbances could happen at many different points in the signaling process, directly affecting ER Ca(2+) channels or interfering with related pathways, which makes it harder to reveal the underlying mechanisms. This review paper also shows that computational modeling is a powerful tool in Ca(2+) signaling studies and discusses the progress in modeling related to Ca(2+) dysregulation in AD research.
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Affiliation(s)
- Jingyi Liang
- Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Christchurch, New Zealand; Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand
| | - Don Kulasiri
- Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Christchurch, New Zealand; Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand.
| | - Sandhya Samarasinghe
- Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Christchurch, New Zealand; Department of Informatics and Enabling Technologies, Lincoln University, Christchurch, New Zealand
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397
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Folch J, Petrov D, Ettcheto M, Pedrós I, Abad S, Beas-Zarate C, Lazarowski A, Marin M, Olloquequi J, Auladell C, Camins A. Masitinib for the treatment of mild to moderate Alzheimer's disease. Expert Rev Neurother 2015; 15:587-96. [PMID: 25961655 DOI: 10.1586/14737175.2015.1045419] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is a degenerative neurological disorder that is the most common cause of dementia and disability in older patients. Available treatments are symptomatic in nature and are only sufficient to improve the quality of life of AD patients temporarily. A potential strategy, currently under investigation, is to target cell-signaling pathways associated with neurodegeneration, in order to decrease neuroinflammation, excitotoxicity, and to improve cognitive functions. Current review centers on the role of neuroinflammation and the specific contribution of mast cells to AD pathophysiology. The authors look at masitinib therapy and the evidence presented through preclinical and clinical trials. Dual actions of masitinib as an inhibitor of mast cell-glia axis and a Fyn kinase blocker are discussed in the context of AD pathology. Masitinib is in Phase III clinical trials for the treatment of malignant melanoma, mastocytosis, multiple myeloma, gastrointestinal cancer and pancreatic cancer. It is also in Phase II/III clinical trials for the treatment of multiple sclerosis, rheumatoid arthritis and AD. Additional research is warranted to better investigate the potential effects of masitinib in combination with other drugs employed in AD treatment.
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Affiliation(s)
- Jaume Folch
- Unitat de Bioquimica i Biotecnología, Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Reus, Tarragona, Spain
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398
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Kalweit AN, Yang H, Colitti-Klausnitzer J, Fülöp L, Bozsó Z, Penke B, Manahan-Vaughan D. Acute intracerebral treatment with amyloid-beta (1-42) alters the profile of neuronal oscillations that accompany LTP induction and results in impaired LTP in freely behaving rats. Front Behav Neurosci 2015; 9:103. [PMID: 25999827 PMCID: PMC4422036 DOI: 10.3389/fnbeh.2015.00103] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/07/2015] [Indexed: 11/30/2022] Open
Abstract
Accumulation of amyloid plaques comprises one of the major hallmarks of Alzheimer’s disease (AD). In rodents, acute treatment with amyloid-beta (Aβ; 1–42) elicits immediate debilitating effects on hippocampal long-term potentiation (LTP). Whereas LTP contributes to synaptic information storage, information is transferred across neurons by means of neuronal oscillations. Furthermore, changes in theta-gamma oscillations, that appear during high-frequency stimulation (HFS) to induce LTP, predict whether successful LTP will occur. Here, we explored if intra-cerebral treatment with Aβ(1–42), that prevents LTP, also results in alterations of hippocampal oscillations that occur during HFS of the perforant path-dentate gyrus synapse in 6-month-old behaving rats. HFS resulted in LTP that lasted for over 24 h. In Aβ-treated animals, LTP was significantly prevented. During HFS, spectral power for oscillations below 100 Hz (δ, θ, α, β and γ) was significantly higher in Aβ-treated animals compared to controls. In addition, the trough-to-peak amplitudes of theta and gamma cycles were higher during HFS in Aβ-treated animals. We also observed a lower amount of envelope-to-signal correlations during HFS in Aβ-treated animals. Overall, the characteristic profile of theta-gamma oscillations that accompany successful LTP induction was disrupted. These data indicate that alterations in network oscillations accompany Aβ-effects on hippocampal LTP. This may comprise an underlying mechanism through which disturbances in synaptic information storage and hippocampus-dependent memory occurs in AD.
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Affiliation(s)
- Alexander Nikolai Kalweit
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany ; International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany
| | - Honghong Yang
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany ; International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany
| | | | - Livia Fülöp
- Department of Medical Chemistry, University of Szeged Szeged, Hungary
| | - Zsolt Bozsó
- Department of Medical Chemistry, University of Szeged Szeged, Hungary
| | - Botond Penke
- Department of Medical Chemistry, University of Szeged Szeged, Hungary
| | - Denise Manahan-Vaughan
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum Bochum, Germany ; International Graduate School of Neuroscience, Ruhr University Bochum Bochum, Germany
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399
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MRZ-99030 – A novel modulator of Aβ aggregation: II – Reversal of Aβ oligomer-induced deficits in long-term potentiation (LTP) and cognitive performance in rats and mice. Neuropharmacology 2015; 92:170-82. [DOI: 10.1016/j.neuropharm.2014.12.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/28/2014] [Accepted: 12/02/2014] [Indexed: 11/21/2022]
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400
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Wilcox KC, Marunde MR, Das A, Velasco PT, Kuhns BD, Marty MT, Jiang H, Luan CH, Sligar SG, Klein WL. Nanoscale Synaptic Membrane Mimetic Allows Unbiased High Throughput Screen That Targets Binding Sites for Alzheimer's-Associated Aβ Oligomers. PLoS One 2015; 10:e0125263. [PMID: 25928376 PMCID: PMC4415972 DOI: 10.1371/journal.pone.0125263] [Citation(s) in RCA: 26] [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: 09/15/2014] [Accepted: 03/23/2015] [Indexed: 01/05/2023] Open
Abstract
Despite their value as sources of therapeutic drug targets, membrane proteomes are largely inaccessible to high-throughput screening (HTS) tools designed for soluble proteins. An important example comprises the membrane proteins that bind amyloid β oligomers (AβOs). AβOs are neurotoxic ligands thought to instigate the synapse damage that leads to Alzheimer's dementia. At present, the identities of initial AβO binding sites are highly uncertain, largely because of extensive protein-protein interactions that occur following attachment of AβOs to surface membranes. Here, we show that AβO binding sites can be obtained in a state suitable for unbiased HTS by encapsulating the solubilized synaptic membrane proteome into nanoscale lipid bilayers (Nanodiscs). This method gives a soluble membrane protein library (SMPL)--a collection of individualized synaptic proteins in a soluble state. Proteins within SMPL Nanodiscs showed enzymatic and ligand binding activity consistent with conformational integrity. AβOs were found to bind SMPL Nanodiscs with high affinity and specificity, with binding dependent on intact synaptic membrane proteins, and selective for the higher molecular weight oligomers known to accumulate at synapses. Combining SMPL Nanodiscs with a mix-incubate-read chemiluminescence assay provided a solution-based HTS platform to discover antagonists of AβO binding. Screening a library of 2700 drug-like compounds and natural products yielded one compound that potently reduced AβO binding to SMPL Nanodiscs, synaptosomes, and synapses in nerve cell cultures. Although not a therapeutic candidate, this small molecule inhibitor of synaptic AβO binding will provide a useful experimental antagonist for future mechanistic studies of AβOs in Alzheimer's model systems. Overall, results provide proof of concept for using SMPLs in high throughput screening for AβO binding antagonists, and illustrate in general how a SMPL Nanodisc system can facilitate drug discovery for membrane protein targets.
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Affiliation(s)
- Kyle C. Wilcox
- Department of Neurobiology, Northwestern University, Evanston, IL, United States of America
| | - Matthew R. Marunde
- Department of Neurobiology, Northwestern University, Evanston, IL, United States of America
| | - Aditi Das
- Department of Comparative Biosciences, University of Illinois—Urbana Champaign, Urbana, IL, United States of America
- Department of Biochemistry, University of Illinois—Urbana Champaign, Urbana, IL, United States of America
| | - Pauline T. Velasco
- Department of Neurobiology, Northwestern University, Evanston, IL, United States of America
| | - Benjamin D. Kuhns
- Department of Neurobiology, Northwestern University, Evanston, IL, United States of America
| | - Michael T. Marty
- Department of Chemistry, University of Illinois—Urbana Champaign, Urbana, IL, United States of America
| | - Haoming Jiang
- Department of Neurobiology, Northwestern University, Evanston, IL, United States of America
| | - Chi-Hao Luan
- High Throughput Analysis Laboratory and Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States of America
| | - Stephen G. Sligar
- Department of Biochemistry, University of Illinois—Urbana Champaign, Urbana, IL, United States of America
- Department of Chemistry, University of Illinois—Urbana Champaign, Urbana, IL, United States of America
| | - William L. Klein
- Department of Neurobiology, Northwestern University, Evanston, IL, United States of America
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