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Jiang Y, Sachdeva K, Goulbourne CN, Berg MJ, Peddy J, Stavrides PH, Pensalfini A, Pawlik M, Whyte L, Balapal BS, Shivakumar S, Bleiwas C, Smiley JF, Mathews PM, Nixon RA. Increased neuronal expression of the early endosomal adaptor APPL1 leads to endosomal and synaptic dysfunction with cholinergic neurodegeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.19.613736. [PMID: 39345644 PMCID: PMC11430014 DOI: 10.1101/2024.09.19.613736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
Dysfunction of the endolysosomal system within neurons is a prominent feature of Alzheimer's disease (AD) pathology. Multiple AD-risk factors are known to cause hyper-activity of the early-endosome small GTPase rab5, resulting in neuronal endosomal pathway disruption. APPL1, an important rab5 effector protein, is an interface between endosomal and neuronal function through a rab5-activating interaction with the BACE1-generated C-terminal fragment (βCTF or C99) of the amyloid precursor protein (APP), a pathogenic APP fragment generated within endolysosomal compartments. To better understand the role of APPL1 in the AD endosomal phenotype, we generated a transgenic mouse model over-expressing human APPL1 within neurons (Thy1-APPL1 mice). Consistent with the important endosomal regulatory role of APPL1, Thy1-APPL1 mice have enlarged neuronal early endosomes and increased synaptic endocytosis due to increased rab5 activation. We additionally demonstrate pathological consequences of APPL1 overexpression, including functional changes in hippocampal long-term potentiation (LTP) and long-term depression (LTD), as well as degeneration of the large projection cholinergic neurons of the basal forebrain and impairment of hippocampal-dependent memory. Our findings show that increased neuronal APPL1 levels lead to a cascade of pathological effects within neurons, including early endosomal alterations, synaptic dysfunction, and neurodegeneration. Multiple risk factors and molecular regulators, including APPL1 activity, are known to contribute to the endosomal dysregulation seen in the early stages of AD, and these findings further highlight the shared pathobiology and consequences to a neuron of early endosomal pathway disruption. Significance Statement Dysfunction in the endolysosomal system within neurons is a key feature of Alzheimer's disease (AD). Multiple AD risk factors lead to hyperactivity of the early-endosome GTPase rab5, disrupting neuronal pathways including the cholinergic circuits involved early in memory decline. APPL1, a crucial rab5 effector, connects endosomal and neuronal functions through its interaction with a specific amyloid precursor protein (APP) fragment generated within endosomes. To understand APPL1's role, a transgenic mouse model over-expressing human APPL1 in neurons (Thy1-APPL1 mice) was developed. These mice show enlarged early endosomes and increased synaptic endocytosis due to rab5 activation, resulting in impaired hippocampal long-term potentiation and depression, the degeneration of basal forebrain cholinergic neurons, and memory deficits, highlighting a pathological cascade mediated through APPL1 at the early endosome.
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Alldred MJ, Pidikiti H, Ibrahim KW, Lee SH, Heguy A, Hoffman GE, Roussos P, Wisniewski T, Wegiel J, Stutzmann GE, Mufson EJ, Ginsberg SD. Analysis of microisolated frontal cortex excitatory layer III and V pyramidal neurons reveals a neurodegenerative phenotype in individuals with Down syndrome. Acta Neuropathol 2024; 148:16. [PMID: 39105932 DOI: 10.1007/s00401-024-02768-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 07/12/2024] [Accepted: 07/13/2024] [Indexed: 08/07/2024]
Abstract
We elucidated the molecular fingerprint of vulnerable excitatory neurons within select cortical lamina of individuals with Down syndrome (DS) for mechanistic understanding and therapeutic potential that also informs Alzheimer's disease (AD) pathophysiology. Frontal cortex (BA9) layer III (L3) and layer V (L5) pyramidal neurons were microisolated from postmortem human DS and age- and sex-matched controls (CTR) to interrogate differentially expressed genes (DEGs) and key biological pathways relevant to neurodegenerative programs. We identified > 2300 DEGs exhibiting convergent dysregulation of gene expression in both L3 and L5 pyramidal neurons in individuals with DS versus CTR subjects. DEGs included over 100 triplicated human chromosome 21 genes in L3 and L5 neurons, demonstrating a trisomic neuronal karyotype in both laminae. In addition, thousands of other DEGs were identified, indicating gene dysregulation is not limited to trisomic genes in the aged DS brain, which we postulate is relevant to AD pathobiology. Convergent L3 and L5 DEGs highlighted pertinent biological pathways and identified key pathway-associated targets likely underlying corticocortical neurodegeneration and related cognitive decline in individuals with DS. Select key DEGs were interrogated as potential hub genes driving dysregulation, namely the triplicated DEGs amyloid precursor protein (APP) and superoxide dismutase 1 (SOD1), along with key signaling DEGs including mitogen activated protein kinase 1 and 3 (MAPK1, MAPK3) and calcium calmodulin dependent protein kinase II alpha (CAMK2A), among others. Hub DEGs determined from multiple pathway analyses identified potential therapeutic candidates for amelioration of cortical neuron dysfunction and cognitive decline in DS with translational relevance to AD.
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Affiliation(s)
- Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
| | - Harshitha Pidikiti
- Center for Dementia Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA
| | - Kyrillos W Ibrahim
- Center for Dementia Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA
| | - Sang Han Lee
- Center for Dementia Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
| | - Adriana Heguy
- Genome Technology Center, New York University Grossman School of Medicine, New York, NY, USA
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA
| | - Gabriel E Hoffman
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Psychiatry and the Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Panos Roussos
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Psychiatry and the Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Thomas Wisniewski
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA
| | - Jerzy Wegiel
- Department of Developmental Neurobiology, Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Grace E Stutzmann
- Center for Neurodegenerative Disease and Therapeutics, Rosalind Franklin University/The Chicago Medical School, North Chicago, IL, USA
| | - Elliott J Mufson
- Department of Translational Neuroscience and Neurology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA.
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA.
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, USA.
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA.
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Liemisa B, Newbury SF, Novy MJ, Pasato JA, Morales-Corraliza J, Peng KY, Mathews PM. Brain apolipoprotein E levels in mice challenged by a Western diet increase in an allele-dependent manner. AGING BRAIN 2023; 4:100102. [PMID: 38058491 PMCID: PMC10696459 DOI: 10.1016/j.nbas.2023.100102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/05/2023] [Accepted: 11/17/2023] [Indexed: 12/08/2023] Open
Abstract
Human apolipoprotein E (APOE) is the greatest determinant of genetic risk for memory deficits and Alzheimer's disease (AD). While APOE4 drives memory loss and high AD risk, APOE2 leads to healthy brain aging and reduced AD risk compared to the common APOE3 variant. We examined brain APOE protein levels in humanized mice homozygous for these alleles and found baseline levels to be age- and isoform-dependent: APOE2 levels were greater than APOE3, which were greater than APOE4. Despite the understanding that APOE lipoparticles do not traverse the blood-brain barrier, we show that brain APOE levels are responsive to dietary fat intake. Challenging mice for 6 months on a Western diet high in fat and cholesterol increased APOE protein levels in an allele-dependent fashion with a much greater increase within blood plasma than within the brain. In the brain, APOE2 levels responded most to the Western diet challenge, increasing by 20 % to 30 %. While increased lipoparticles are generally deleterious in the periphery, we propose that higher brain APOE2 levels may represent a readily available pool of beneficial lipid particles for neurons.
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Affiliation(s)
- Braison Liemisa
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Samantha F. Newbury
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Mariah J. Novy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Jonathan A. Pasato
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Jose Morales-Corraliza
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Katherine Y. Peng
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Paul M. Mathews
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY 10016, USA
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016, USA
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Agrawal RR, Larrea D, Xu Y, Shi L, Zirpoli H, Cummins LG, Emmanuele V, Song D, Yun TD, Macaluso FP, Min W, Kernie SG, Deckelbaum RJ, Area-Gomez E. Alzheimer's-Associated Upregulation of Mitochondria-Associated ER Membranes After Traumatic Brain Injury. Cell Mol Neurobiol 2023; 43:2219-2241. [PMID: 36571634 PMCID: PMC10287820 DOI: 10.1007/s10571-022-01299-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 10/04/2022] [Indexed: 12/27/2022]
Abstract
Traumatic brain injury (TBI) can lead to neurodegenerative diseases such as Alzheimer's disease (AD) through mechanisms that remain incompletely characterized. Similar to AD, TBI models present with cellular metabolic alterations and modulated cleavage of amyloid precursor protein (APP). Specifically, AD and TBI tissues display increases in amyloid-β as well as its precursor, the APP C-terminal fragment of 99 a.a. (C99). Our recent data in cell models of AD indicate that C99, due to its affinity for cholesterol, induces the formation of transient lipid raft domains in the ER known as mitochondria-associated endoplasmic reticulum (ER) membranes ("MAM" domains). The formation of these domains recruits and activates specific lipid metabolic enzymes that regulate cellular cholesterol trafficking and sphingolipid turnover. Increased C99 levels in AD cell models promote MAM formation and significantly modulate cellular lipid homeostasis. Here, these phenotypes were recapitulated in the controlled cortical impact (CCI) model of TBI in adult mice. Specifically, the injured cortex and hippocampus displayed significant increases in C99 and MAM activity, as measured by phospholipid synthesis, sphingomyelinase activity and cholesterol turnover. In addition, our cell type-specific lipidomics analyses revealed significant changes in microglial lipid composition that are consistent with the observed alterations in MAM-resident enzymes. Altogether, we propose that alterations in the regulation of MAM and relevant lipid metabolic pathways could contribute to the epidemiological connection between TBI and AD.
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Affiliation(s)
- Rishi R Agrawal
- Institute of Human Nutrition, Columbia University Irving Medical Center, 630 W. 168th St., Presbyterian Hospital 15E-1512, New York, NY, 10032, USA.
- Denali Therapeutics Inc., 161 Oyster Point Blvd., South San Francisco, CA, 94080, USA.
| | - Delfina Larrea
- Department of Neurology, Neurological Institute, Columbia University Irving Medical Center, 710 W. 168th St., New York, NY, 10032, USA
| | - Yimeng Xu
- Biomarkers Core Laboratory, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, 622 W. 168th St., Presbyterian Hospital 10-105, New York, NY, 10032, USA
| | - Lingyan Shi
- Department of Chemistry, Columbia University, 3000 Broadway, Havemeyer Hall, New York, NY, 10027, USA
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Hylde Zirpoli
- Institute of Human Nutrition, Columbia University Irving Medical Center, 630 W. 168th St., Presbyterian Hospital 15E-1512, New York, NY, 10032, USA
| | - Leslie G Cummins
- Analytical Imaging Facility, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY, 10461, USA
| | - Valentina Emmanuele
- Department of Neurology, Neurological Institute, Columbia University Irving Medical Center, 710 W. 168th St., New York, NY, 10032, USA
| | - Donghui Song
- Department of Chemistry, Columbia University, 3000 Broadway, Havemeyer Hall, New York, NY, 10027, USA
| | - Taekyung D Yun
- Department of Neurology, Neurological Institute, Columbia University Irving Medical Center, 710 W. 168th St., New York, NY, 10032, USA
| | - Frank P Macaluso
- Analytical Imaging Facility, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY, 10461, USA
| | - Wei Min
- Biomarkers Core Laboratory, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, 622 W. 168th St., Presbyterian Hospital 10-105, New York, NY, 10032, USA
| | - Steven G Kernie
- Department of Neurology, Neurological Institute, Columbia University Irving Medical Center, 710 W. 168th St., New York, NY, 10032, USA
- Department of Pediatrics, Columbia University Irving Medical Center, 622 W. 168th St., Presbyterian Hospital 17, New York, NY, 10032, USA
| | - Richard J Deckelbaum
- Institute of Human Nutrition, Columbia University Irving Medical Center, 630 W. 168th St., Presbyterian Hospital 15E-1512, New York, NY, 10032, USA
- Department of Pediatrics, Columbia University Irving Medical Center, 622 W. 168th St., Presbyterian Hospital 17, New York, NY, 10032, USA
| | - Estela Area-Gomez
- Institute of Human Nutrition, Columbia University Irving Medical Center, 630 W. 168th St., Presbyterian Hospital 15E-1512, New York, NY, 10032, USA.
- Department of Neurology, Neurological Institute, Columbia University Irving Medical Center, 710 W. 168th St., New York, NY, 10032, USA.
- Centro de Investigaciones Biológicas Margarita Salas - CSIC, C. Ramiro de Maeztu, 9, 28040, Madrid, Spain.
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Gabriele RMC, Abel E, Fox NC, Wray S, Arber C. Knockdown of Amyloid Precursor Protein: Biological Consequences and Clinical Opportunities. Front Neurosci 2022; 16:835645. [PMID: 35360155 PMCID: PMC8964081 DOI: 10.3389/fnins.2022.835645] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/18/2022] [Indexed: 12/29/2022] Open
Abstract
Amyloid precursor protein (APP) and its cleavage fragment Amyloid-β (Aβ) have fundamental roles in Alzheimer's disease (AD). Genetic alterations that either increase the overall dosage of APP or alter its processing to favour the generation of longer, more aggregation prone Aβ species, are directly causative of the disease. People living with one copy of APP are asymptomatic and reducing APP has been shown to lower the relative production of aggregation-prone Aβ species in vitro. For these reasons, reducing APP expression is an attractive approach for AD treatment and prevention. In this review, we will describe the structure and the known functions of APP and go on to discuss the biological consequences of APP knockdown and knockout in model systems. We highlight progress in therapeutic strategies to reverse AD pathology via reducing APP expression. We conclude that new technologies that reduce the dosage of APP expression may allow disease modification and slow clinical progression, delaying or even preventing onset.
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Affiliation(s)
- Rebecca M. C. Gabriele
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Emily Abel
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom,UK Dementia Research Institute at University College London (UCL), Queen Square Institute of Neurology, London, United Kingdom
| | - Nick C. Fox
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom,UK Dementia Research Institute at University College London (UCL), Queen Square Institute of Neurology, London, United Kingdom
| | - Selina Wray
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Charles Arber
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom,*Correspondence: Charles Arber,
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Novy MJ, Newbury SF, Liemisa B, Morales-Corraliza J, Alldred MJ, Ginsberg SD, Mathews PM. Expression and proteolytic processing of the amyloid precursor protein is unaffected by the expression of the three human apolipoprotein E alleles in the brains of mice. Neurobiol Aging 2022; 110:73-76. [PMID: 34875506 PMCID: PMC8758539 DOI: 10.1016/j.neurobiolaging.2021.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 02/03/2023]
Abstract
The 3 human apolipoprotein E (APOE) gene alleles modify an individual's risk of developing Alzheimer's disease (AD): compared to the risk-neutral APOE ε3 allele, the ε4 allele (APOE4) is strongly associated with increased AD risk while the ε2 allele is protective. Multiple mechanisms have been shown to link APOE4 expression and AD risk, including the possibility that APOE4 increases the expression of the amyloid precursor protein (APP) (Y-W.A. Huang, B. Zhou, A.M. Nabet, M. Wernig, T.C. Südhof, 2019). In this study, we investigated the impact of APOE genotype on the expression, and proteolytic processing of endogenously expressed APP in the brains of mice humanized for the 3 APOE alleles. In contrast to prior studies using neuronal cultures, we found in the brain that both App gene expression, and the levels of APP holoprotein were not affected by APOE genotype. Additionally, our analysis of APP fragments showed that APOE genotype does not impact APP processing in the brain: the levels of both α- and β-cleaved soluble APP fragments (sAPPs) were similar across genotypes, as were the levels of the membrane-associated α- and β-cleaved C-terminal fragments (CTFs) of APP. Lastly, APOE genotype did not impact the level of soluble amyloid beta (Aβ). These findings argue that the APOE-allele-dependent AD risk is independent of the brain expression and processing of APP.
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Affiliation(s)
- Mariah J Novy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Samantha F Newbury
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Braison Liemisa
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Jose Morales-Corraliza
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Health, New York, NY, USA
| | - Melissa J Alldred
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Health, New York, NY, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Health, New York, NY, USA; NYU Neuroscience Institute, New York University Langone Health, New York, NY, USA; Department of Neuroscience and Physiology, New York University Langone Health, New York, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Health, New York, NY, USA; NYU Neuroscience Institute, New York University Langone Health, New York, NY, USA.
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Pelucchi S, Gardoni F, Di Luca M, Marcello E. Synaptic dysfunction in early phases of Alzheimer's Disease. HANDBOOK OF CLINICAL NEUROLOGY 2022; 184:417-438. [PMID: 35034752 DOI: 10.1016/b978-0-12-819410-2.00022-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The synapse is the locus of plasticity where short-term alterations in synaptic strength are converted to long-lasting memories. In addition to the presynaptic terminal and the postsynaptic compartment, a more holistic view of the synapse includes the astrocytes and the extracellular matrix to form a tetrapartite synapse. All these four elements contribute to synapse health and are crucial for synaptic plasticity events and, thereby, for learning and memory processes. Synaptic dysfunction is a common pathogenic trait of several brain disorders. In Alzheimer's Disease, the degeneration of synapses can be detected at the early stages of pathology progression before neuronal degeneration, supporting the hypothesis that synaptic failure is a major determinant of the disease. The synapse is the place where amyloid-β peptides are generated and is the target of the toxic amyloid-β oligomers. All the elements constituting the tetrapartite synapse are altered in Alzheimer's Disease and can synergistically contribute to synaptic dysfunction. Moreover, the two main hallmarks of Alzheimer's Disease, i.e., amyloid-β and tau, act in concert to cause synaptic deficits. Deciphering the mechanisms underlying synaptic dysfunction is relevant for the development of the next-generation therapeutic strategies aimed at modifying the disease progression.
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Affiliation(s)
- Silvia Pelucchi
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - Fabrizio Gardoni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - Monica Di Luca
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy.
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Shroff UN, Gyarmati G, Izuhara A, Deepak S, Peti-Peterdi J. A new view of macula densa cell protein synthesis. Am J Physiol Renal Physiol 2021; 321:F689-F704. [PMID: 34693742 PMCID: PMC8714974 DOI: 10.1152/ajprenal.00222.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 11/22/2022] Open
Abstract
Macula densa (MD) cells, a chief sensory cell type in the nephron, are endowed with unique microanatomic features including a high density of protein synthetic organelles and secretory vesicles in basal cell processes ("maculapodia") that suggest a so far unknown high rate of MD protein synthesis. This study aimed to explore the rate and regulation of MD protein synthesis and their effects on glomerular function using novel transgenic mouse models, newly established fluorescence cell biology techniques, and intravital microscopy. Sox2-tdTomato kidney tissue sections and an O-propargyl puromycin incorporation-based fluorescence imaging assay showed that MD cells have the highest level of protein synthesis within the kidney cortex followed by intercalated cells and podocytes. Genetic gain of function of mammalian target of rapamycin (mTOR) signaling specifically in MD cells (in MD-mTORgof mice) or their physiological activation by low-salt diet resulted in further significant increases in the synthesis of MD proteins. Specifically, these included both classic and recently identified MD-specific proteins such as cyclooxygenase 2, microsomal prostaglandin E2 synthase 1, and pappalysin 2. Intravital imaging of the kidney using multiphoton microscopy showed significant increases in afferent and efferent arteriole and glomerular capillary diameters and blood flow in MD-mTORgof mice coupled with an elevated glomerular filtration rate. The presently identified high rate of MD protein synthesis that is regulated by mTOR signaling is a novel component of the physiological activation and glomerular hemodynamic regulatory functions of MD cells that remains to be fully characterized.NEW & NOTEWORTHY This study discovered the high rate of protein synthesis in macula densa (MD) cells by applying direct imaging techniques with single cell resolution. Physiological activation and mammalian target of rapamycin signaling played important regulatory roles in this process. This new feature is a novel component of the tubuloglomerular cross talk and glomerular hemodynamic regulatory functions of MD cells. Future work is needed to elucidate the nature and (patho)physiological role of the specific proteins synthesized by MD cells.
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Affiliation(s)
- Urvi Nikhil Shroff
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Georgina Gyarmati
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Audrey Izuhara
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Sachin Deepak
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
- Department of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - János Peti-Peterdi
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California
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Tau Is Truncated in Five Regions of the Normal Adult Human Brain. Int J Mol Sci 2021; 22:ijms22073521. [PMID: 33805376 PMCID: PMC8036332 DOI: 10.3390/ijms22073521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 01/01/2023] Open
Abstract
The truncation of Tau is thought to be important in promoting aggregation, with this feature characterising the pathology of dementias such as Alzheimer disease. Antibodies to the C-terminal and N-terminal regions of Tau were employed to examine Tau cleavage in five human brain regions: the entorhinal cortex, prefrontal cortex, motor cortex, hippocampus, and cerebellum. These were obtained from normal subjects ranging in age from 18 to 104 years. Tau fragments of approximately 40 kDa and 45 kDa with an intact N-terminus retained were found in soluble and insoluble brain fractions. In addition, smaller C-terminal Tau fragments ranging in mass from 17 kDa to 25 kDa were also detected. These findings are consistent with significant Tau cleavage taking place in brain regions from 18 years onwards. It appears that site-specific cleavage of Tau is widespread in the normal human brain, and that large Tau fragments that contain the N-terminus, as well as shorter C-terminal Tau fragments, are present in brain cells across the age range.
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Gourmaud S, Shou H, Irwin DJ, Sansalone K, Jacobs LM, Lucas TH, Marsh ED, Davis KA, Jensen FE, Talos DM. Alzheimer-like amyloid and tau alterations associated with cognitive deficit in temporal lobe epilepsy. Brain 2020; 143:191-209. [PMID: 31834353 DOI: 10.1093/brain/awz381] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/08/2019] [Accepted: 10/17/2019] [Indexed: 01/27/2023] Open
Abstract
Temporal lobe epilepsy represents a major cause of drug-resistant epilepsy. Cognitive impairment is a frequent comorbidity, but the mechanisms are not fully elucidated. We hypothesized that the cognitive impairment in drug-resistant temporal lobe epilepsy could be due to perturbations of amyloid and tau signalling pathways related to activation of stress kinases, similar to those observed in Alzheimer's disease. We examined these pathways, as well as amyloid-β and tau pathologies in the hippocampus and temporal lobe cortex of drug-resistant temporal lobe epilepsy patients who underwent temporal lobe resection (n = 19), in comparison with age- and region-matched samples from neurologically normal autopsy cases (n = 22). Post-mortem temporal cortex samples from Alzheimer's disease patients (n = 9) were used as positive controls to validate many of the neurodegeneration-related antibodies. Western blot and immunohistochemical analysis of tissue from temporal lobe epilepsy cases revealed increased phosphorylation of full-length amyloid precursor protein and its associated neurotoxic cleavage product amyloid-β*56. Pathological phosphorylation of two distinct tau species was also increased in both regions, but increases in amyloid-β1-42 peptide, the main component of amyloid plaques, were restricted to the hippocampus. Furthermore, several major stress kinases involved in the development of Alzheimer's disease pathology were significantly activated in temporal lobe epilepsy brain samples, including the c-Jun N-terminal kinase and the protein kinase R-like endoplasmic reticulum kinase. In temporal lobe epilepsy cases, hippocampal levels of phosphorylated amyloid precursor protein, its pro-amyloidogenic processing enzyme beta-site amyloid precursor protein cleaving enzyme 1, and both total and hyperphosphorylated tau expression, correlated with impaired preoperative executive function. Our study suggests that neurodegenerative and stress-related processes common to those observed in Alzheimer's disease may contribute to cognitive impairment in drug-resistant temporal lobe epilepsy. In particular, we identified several stress pathways that may represent potential novel therapeutic targets.
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Affiliation(s)
- Sarah Gourmaud
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Haochang Shou
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David J Irwin
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Penn Frontotemporal Degeneration Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Kimberly Sansalone
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leah M Jacobs
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy H Lucas
- Department of Neurosurgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Eric D Marsh
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kathryn A Davis
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Delia M Talos
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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11
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Tambini MD, Norris KA, D'Adamio L. Opposite changes in APP processing and human Aβ levels in rats carrying either a protective or a pathogenic APP mutation. eLife 2020; 9:52612. [PMID: 32022689 PMCID: PMC7018507 DOI: 10.7554/elife.52612] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/03/2020] [Indexed: 12/13/2022] Open
Abstract
Cleavage of APP by BACE1/β-secretase initiates the amyloidogenic cascade leading to Amyloid-β (Aβ) production. α-Secretase initiates the non-amyloidogenic pathway preventing Aβ production. Several APP mutations cause familial Alzheimer's disease (AD), while the Icelandic APP mutation near the BACE1-cleavage site protects from sporadic dementia, emphasizing APP's role in dementia pathogenesis. To study APP protective/pathogenic mechanisms, we generated knock-in rats carrying either the protective (Appp) or the pathogenic Swedish mutation (Apps), also located near the BACE1-cleavage site. α-Cleavage is favored over β-processing in Appp rats. Consequently, non-amyloidogenic and amyloidogenic APP metabolites are increased and decreased, respectively. The reverse APP processing shift occurs in Apps rats. These opposite effects on APP β/α-processing suggest that protection from and pathogenesis of dementia depend upon combinatorial and opposite alterations in APP metabolism rather than simply on Aβ levels. The Icelandic mutation also protects from aging-dependent cognitive decline, suggesting that similar mechanisms underlie physiological cognitive aging.
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Affiliation(s)
- Marc D Tambini
- Department of Pharmacology Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Kelly A Norris
- Department of Pharmacology Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Luciano D'Adamio
- Department of Pharmacology Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
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12
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Iwata M, Watanabe S, Yamane A, Miyasaka T, Misonou H. Regulatory mechanisms for the axonal localization of tau protein in neurons. Mol Biol Cell 2019; 30:2441-2457. [PMID: 31364926 PMCID: PMC6743362 DOI: 10.1091/mbc.e19-03-0183] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Tau is a microtubule (MT)-associated protein that is thought to be localized to the axon. However, its precise localization in developing neurons and mechanisms for the axonal localization have not been fully addressed. In this study, we found that the axonal localization of tau in cultured rat hippocampal neurons mainly occur during early neuronal development. Interestingly, transient expression of human tau in very immature neurons, but not in mature neurons, mimicked the developmental localization of endogenous tau to the axon. We therefore were able to establish an experimental model, in which exogenously expressed tau can be properly localized to the axon. Using this model, we obtained a surprising finding that the axonal localization of tau did not require stable MT binding. Tau lacking the MT-binding domain (MTBD) exhibited high diffusivity but localized properly to the axon. In contrast, a dephosphorylation-mimetic mutant of the proline-rich region 2 showed reinforced MT binding and mislocalization. Our results suggest that tight binding to MTs prevents tau from entering the axon and results in mislocalization in the soma and dendrites when expressed in mature neurons. This study therefore provides a novel mechanism independent of MTBD for the axonal localization of tau.
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Affiliation(s)
- Minori Iwata
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Shoji Watanabe
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Ayaka Yamane
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Tomohiro Miyasaka
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan.,Center for Research in Neurodegenerative Diseases, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Hiroaki Misonou
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan.,Center for Research in Neurodegenerative Diseases, Doshisha University, Kyotanabe-shi, Kyoto 610-0394, Japan
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13
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Alldred MJ, Chao HM, Lee SH, Beilin J, Powers BE, Petkova E, Strupp BJ, Ginsberg SD. Long-term effects of maternal choline supplementation on CA1 pyramidal neuron gene expression in the Ts65Dn mouse model of Down syndrome and Alzheimer's disease. FASEB J 2019; 33:9871-9884. [PMID: 31180719 DOI: 10.1096/fj.201802669rr] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Choline is critical for normative function of 3 major pathways in the brain, including acetylcholine biosynthesis, being a key mediator of epigenetic regulation, and serving as the primary substrate for the phosphatidylethanolamine N-methyltransferase pathway. Sufficient intake of dietary choline is critical for proper brain function and neurodevelopment. This is especially important for brain development during the perinatal period. Current dietary recommendations for choline intake were undertaken without critical evaluation of maternal choline levels. As such, recommended levels may be insufficient for both mother and fetus. Herein, we examined the impact of perinatal maternal choline supplementation (MCS) in a mouse model of Down syndrome and Alzheimer's disease, the Ts65Dn mouse relative to normal disomic littermates, to examine the effects on gene expression within adult offspring at ∼6 and 11 mo of age. We found MCS produces significant changes in offspring gene expression levels that supersede age-related and genotypic gene expression changes. Alterations due to MCS impact every gene ontology category queried, including GABAergic neurotransmission, the endosomal-lysosomal pathway and autophagy, and neurotrophins, highlighting the importance of proper choline intake during the perinatal period, especially when the fetus is known to have a neurodevelopmental disorder such as trisomy.-Alldred, M. J., Chao, H. M., Lee, S. H., Beilin, J., Powers, B. E., Petkova, E., Strupp, B. J., Ginsberg, S. D. Long-term effects of maternal choline supplementation on CA1 pyramidal neuron gene expression in the Ts65Dn mouse model of Down syndrome and Alzheimer's disease.
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Affiliation(s)
- Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, (NYU) Langone Medical Center, New York, New York, USA
| | - Helen M Chao
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, (NYU) Langone Medical Center, New York, New York, USA
| | - Sang Han Lee
- Center for Biomedical Imaging and Neuromodulation, Nathan Kline Institute, Orangeburg, New York, USA.,Department Neuroscience and Physiology, (NYU) Langone Medical Center, New York, New York, USA
| | - Judah Beilin
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA
| | - Brian E Powers
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | - Eva Petkova
- Child Psychiatry, Nathan Kline Institute, Orangeburg, New York, USA.,Department of Child and Adolescent Psychiatry, (NYU) Langone Medical Center, New York, New York, USA
| | - Barbara J Strupp
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.,Department of Psychology, Cornell University, Ithaca, New York, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, USA.,Department of Psychiatry, (NYU) Langone Medical Center, New York, New York, USA.,Department Neuroscience and Physiology, (NYU) Langone Medical Center, New York, New York, USA.,New York University (NYU) Neuroscience Institute, NYU Langone Medical Center, New York, New York, USA
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14
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High resolution approaches for the identification of amyloid fragments in brain. J Neurosci Methods 2019; 319:7-15. [PMID: 30367888 DOI: 10.1016/j.jneumeth.2018.10.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/15/2018] [Accepted: 10/22/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND It is now widely recognized that endogenous, picomolar concentrations of the 42 amino acid long peptide, amyloid-β (Aβ42) is secreted under normal physiological conditions and exerts important functional activity throughout neuronal intracellular compartments. Transgenic animal models that overexpress Aβ42 and its precursor, amyloid precursor protein (APP), have not provided predictive value in testing new treatments for Alzheimer's disease (AD), resulting in failed clinical trials. While these results are discouraging, they underscore the need to understand the physiological roles of Aβ42 and APP under normal conditions as well as at early pre- symptomatic stages of AD. New method: We describe the use of acrolein-perfusion in immunoelectron microscopy in combination with novel antibodies directed against endogenous murine Aβ42 and APP fragments to study abnormalities in the endolysosomal system at early stages of disease. The specific requirements, limitations and advantages of novel antibodies directed against human and murine Aβ42, APP and APP fragments are discussed as well as parameters for ultrastructural analysis of endolysosomal compartments. RESULTS Novel antibodies and a detailed protocol for immunoelectron microscopy using acrolein as a fixative are described. Acrolein is shown to preserve intraneuronal Aβ42 species, as opposed to paraformaldehyde fixed tissue, which primarily preserves membrane bound species. Comparison with existing method(s): Technology sensitive enough to detect endogenous Aβ42 under physiological conditions has not been widely available. We describe a number of novel and highly sensitive antibodies have recently been developed that may facilitate the analysis of endogenous Aβ42. CONCLUSIONS Using novel and highly specific antibodies in combination with electron microscopy may reveal important information about the timing of aberrant protein accumulation, as well as the progression of abnormalities in the endolysosomal systems that sort and clear these peptides.
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15
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Natural Peptides in Drug Discovery Targeting Acetylcholinesterase. Molecules 2018; 23:molecules23092344. [PMID: 30217053 PMCID: PMC6225273 DOI: 10.3390/molecules23092344] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/06/2018] [Accepted: 09/12/2018] [Indexed: 12/16/2022] Open
Abstract
Acetylcholinesterase-inhibitory peptide has gained much importance since it can inhibit acetylcholinesterase (AChE) and increase the availability of acetylcholine in cholinergic synapses, enhancing cholinergic transmission in pharmacological treatment of Alzheimer’s disease (AD). Natural peptides have received considerable attention as biologically important substances as a source of AChE inhibitors. These natural peptides have high potential pharmaceutical and medicinal values due to their bioactivities as neuroprotective and neurodegenerative treatment activities. These peptides have attracted great interest in the pharmaceutical industries, in order to design potential peptides for use in the prophylactic and therapy purposes. Some natural peptides and their derivatives have high commercial values and have succeeded in reaching the pharmaceutical market. A large number of peptides are already in preclinical and clinical pipelines for treatment of various diseases. This review highlights the recent researches on the various natural peptides and future prospects for AD management.
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16
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Gulisano W, Melone M, Li Puma DD, Tropea MR, Palmeri A, Arancio O, Grassi C, Conti F, Puzzo D. The effect of amyloid-β peptide on synaptic plasticity and memory is influenced by different isoforms, concentrations, and aggregation status. Neurobiol Aging 2018; 71:51-60. [PMID: 30092511 DOI: 10.1016/j.neurobiolaging.2018.06.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/28/2018] [Accepted: 06/19/2018] [Indexed: 01/06/2023]
Abstract
The increase of oligomeric amyloid-beta (oAβ) has been related to synaptic dysfunction, thought to be the earliest event in Alzheimer's disease pathophysiology. Conversely, the suppression of endogenous Aβ impaired synaptic plasticity and memory, suggesting that the peptide is needed in the healthy brain. However, different species, aggregation forms and concentrations of Aβ might differently influence synaptic function/dysfunction. Here, we have tested the contribution of monomeric and oligomeric Aβ42 and Aβ40 at 200 nM and 200 pM concentrations on hippocampal long-term potentiation and spatial memory. We found that, when at 200 nM, oAβ40, oAβ42, and monomeric Aβ42 impaired long-term potentiation and memory, whereas only oAβ42 200 pM enhanced synaptic plasticity and memory and rescued the detrimental effect due to depletion of endogenous Aβ. Interestingly, quantification of monomer-like and oligomer-like species carried out by transmission electron microscopy revealed an increase of the monomer/oligomer ratio in the oAβ42 200 pM preparation, suggesting that the content of monomers and oligomers depends on the final concentration of the solution.
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Affiliation(s)
- Walter Gulisano
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Marcello Melone
- Department Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Università Politecnica delle Marche, Ancona, Italy; Center for Neurobiology of Aging, INRCA IRCCS, Ancona, Italy
| | - Domenica D Li Puma
- Institute of Human Physiology, Università Cattolica Medical School, Rome, Italy
| | - Maria Rosaria Tropea
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Agostino Palmeri
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica Medical School, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, Rome, Italy
| | - Fiorenzo Conti
- Department Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Università Politecnica delle Marche, Ancona, Italy; Center for Neurobiology of Aging, INRCA IRCCS, Ancona, Italy; Foundation for Molecular Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Daniela Puzzo
- Department Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.
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17
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Pantelopulos GA, Straub JE, Thirumalai D, Sugita Y. Structure of APP-C99 1-99 and implications for role of extra-membrane domains in function and oligomerization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1698-1708. [PMID: 29702072 DOI: 10.1016/j.bbamem.2018.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 01/30/2023]
Abstract
The 99 amino acid C-terminal fragment of Amyloid Precursor Protein APP-C99 (C99) is cleaved by γ-secretase to form Aβ peptide, which plays a critical role in the etiology of Alzheimer's Disease (AD). The structure of C99 consists of a single transmembrane domain flanked by intra and intercellular domains. While the structure of the transmembrane domain has been well characterized, little is known about the structure of the flanking domains and their role in C99 processing by γ-secretase. To gain insight into the structure of full-length C99, REMD simulations were performed for monomeric C99 in model membranes of varying thickness. We find equilibrium ensembles of C99 from simulation agree with experimentally-inferred residue insertion depths and protein backbone chemical shifts. In thin membranes, the transmembrane domain structure is correlated with extra-membrane structural states and the extra-membrane domain structural states become less correlated to each other. Mean and variance of the transmembrane and G37G38 hinge angles are found to increase with thinning membrane. The N-terminus of C99 forms β-strands that may seed aggregation of Aβ on the membrane surface, promoting amyloid formation. In thicker membranes the N-terminus forms α-helices that interact with the nicastrin domain of γ-secretase. The C-terminus of C99 becomes more α-helical as the membrane thickens, forming structures that may be suitable for binding by cytoplasmic proteins, while C-terminal residues essential to cytotoxic function become α-helical as the membrane thins. The heterogeneous but discrete extra-membrane domain states analyzed here open the path to new investigations of the role of C99 structure and membrane in amyloidogenesis. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- George A Pantelopulos
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215-2521, USA
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215-2521, USA.
| | - D Thirumalai
- Department of Chemistry, The University of Texas, Austin, TX 78712-1224, USA
| | - Yuji Sugita
- Theoretical Molecular Science Laboratory, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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18
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Abstract
High levels of amyloid-β peptide (Aβ) have been related to Alzheimer's disease pathogenesis. However, in the healthy brain, low physiologically relevant concentrations of Aβ are necessary for long-term potentiation (LTP) and memory. Because cGMP plays a key role in these processes, here we investigated whether the cyclic nucleotide cGMP influences Aβ levels and function during LTP and memory. We demonstrate that the increase of cGMP levels by the phosphodiesterase-5 inhibitors sildenafil and vardenafil induces a parallel release of Aβ due to a change in the approximation of amyloid precursor protein (APP) and the β-site APP cleaving enzyme 1. Moreover, electrophysiological and behavioral studies performed on animals of both sexes showed that blocking Aβ function, by using anti-murine Aβ antibodies or APP knock-out mice, prevents the cGMP-dependent enhancement of LTP and memory. Our data suggest that cGMP positively regulates Aβ levels in the healthy brain which, in turn, boosts synaptic plasticity and memory.SIGNIFICANCE STATEMENT Amyloid-β (Aβ) is a key pathogenetic factor in Alzheimer's disease. However, low concentrations of endogenous Aβ, mimicking levels of the peptide in the healthy brain, enhance hippocampal long-term potentiation (LTP) and memory. Because the second messenger cGMP exerts a central role in LTP mechanisms, here we studied whether cGMP affects Aβ levels and function during LTP. We show that cGMP enhances Aβ production by increasing the APP/BACE-1 convergence in endolysosomal compartments. Moreover, the cGMP-induced enhancement of LTP and memory was disrupted by blockade of Aβ, suggesting that the physiological effect of the cyclic nucleotide on LTP and memory is dependent upon Aβ.
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19
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Not just amyloid: physiological functions of the amyloid precursor protein family. Nat Rev Neurosci 2017; 18:281-298. [PMID: 28360418 DOI: 10.1038/nrn.2017.29] [Citation(s) in RCA: 387] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyloid precursor protein (APP) gives rise to the amyloid-β peptide and thus has a key role in the pathogenesis of Alzheimer disease. By contrast, the physiological functions of APP and the closely related APP-like proteins (APLPs) remain less well understood. Studying these physiological functions has been challenging and has required a careful long-term strategy, including the analysis of different App-knockout and Aplp-knockout mice. In this Review, we summarize these findings, focusing on the in vivo roles of APP family members and their processing products for CNS development, synapse formation and function, brain injury and neuroprotection, as well as ageing. In addition, we discuss the implications of APP physiology for therapeutic approaches.
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20
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Asai M, Kinjo A, Kimura S, Mori R, Kawakubo T, Shirotani K, Yagishita S, Maruyama K, Iwata N. Perturbed Calcineurin-NFAT Signaling Is Associated with the Development of Alzheimer's Disease. Biol Pharm Bull 2017; 39:1646-1652. [PMID: 27725441 DOI: 10.1248/bpb.b16-00350] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Down syndrome (DS), the most common genetic disorder, is caused by trisomy 21. DS is accompanied by heart defects, hearing and vision problems, obesity, leukemia, and other conditions, including Alzheimer's disease (AD). In comparison, most cancers are rare in people with DS. Overexpression of dual specificity tyrosine-phosphorylation-regulated kinase 1A and a regulator of calcineurin 1 located on chromosome 21 leads to excessive suppression of the calcineurin-nuclear factor of activated T cells (NFAT) signaling pathway, resulting in reduced expression of a critical angiogenic factor. However, it is unclear whether the calcineurin-NFAT signaling pathway is involved in AD pathology in DS patients. Here, we investigated the association between the calcineurin-NFAT signaling pathway and AD using neuronal cells. Short-term pharmacological stimulation decreased gene expression of tau and neprilysin, and long-term inhibition of the signaling pathway decreased that of amyloid precursor protein. Moreover, a calcineurin inhibitor, cyclosporine A, also decreased neprilysin activity, leading to increases in amyloid-β peptide levels. Taken together, our results suggest that a dysregulation in calcineurin-NFAT signaling may contribute to the early onset of AD in people with DS.
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Affiliation(s)
- Masashi Asai
- School of Pharmaceutical Sciences, Nagasaki University
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21
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Brain-Wide Insulin Resistance, Tau Phosphorylation Changes, and Hippocampal Neprilysin and Amyloid-β Alterations in a Monkey Model of Type 1 Diabetes. J Neurosci 2016; 36:4248-58. [PMID: 27076423 DOI: 10.1523/jneurosci.4640-14.2016] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/02/2016] [Indexed: 02/08/2023] Open
Abstract
UNLABELLED Epidemiological findings suggest that diabetic individuals are at a greater risk for developing Alzheimer's disease (AD). To examine the mechanisms by which diabetes mellitus (DM) may contribute to AD pathology in humans, we examined brain tissue from streptozotocin-treated type 1 diabetic adult male vervet monkeys receiving twice-daily exogenous insulin injections for 8-20 weeks. We found greater inhibitory phosphorylation of insulin receptor substrate 1 in each brain region examined of the diabetic monkeys when compared with controls, consistent with a pattern of brain insulin resistance that is similar to that reported in the human AD brain. Additionally, a widespread increase in phosphorylated tau was seen, including brain areas vulnerable in AD, as well as relatively spared structures, such as the cerebellum. An increase in active ERK1/2 was also detected, consistent with DM leading to changes in tau-kinase activity broadly within the brain. In contrast to these widespread changes, we found an increase in soluble amyloid-β (Aβ) levels that was restricted to the temporal lobe, with the greatest increase seen in the hippocampus. Consistent with this localized Aβ increase, a hippocampus-restricted decrease in the protein and mRNA for the Aβ-degrading enzyme neprilysin (NEP) was found, whereas various Aβ-clearing and -degrading proteins were unchanged. Thus, we document multiple biochemical changes in the insulin-controlled DM monkey brain that can link DM with the risk of developing AD, including dysregulation of the insulin-signaling pathway, changes in tau phosphorylation, and a decrease in NEP expression in the hippocampus that is coupled with a localized increase in Aβ. SIGNIFICANCE STATEMENT Given that diabetes mellitus (DM) appears to increase the risk of developing Alzheimer's disease (AD), understanding the mechanisms by which DM promotes AD is important. We report that DM in a nonhuman primate brain leads to changes in the levels or posttranslational processing of proteins central to AD pathobiology, including tau, amyloid-β (Aβ), and the Aβ-degrading protease neprilysin. Additional evidence from this model suggests that alterations in brain insulin signaling occurred that are reminiscent of insulin signaling pathway changes seen in human AD. Thus, in an in vivo model highly relevant to humans, we show multiple alterations in the brain resulting from DM that are mechanistically linked to AD risk.
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22
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Novotny R, Langer F, Mahler J, Skodras A, Vlachos A, Wegenast-Braun BM, Kaeser SA, Neher JJ, Eisele YS, Pietrowski MJ, Nilsson KPR, Deller T, Staufenbiel M, Heimrich B, Jucker M. Conversion of Synthetic Aβ to In Vivo Active Seeds and Amyloid Plaque Formation in a Hippocampal Slice Culture Model. J Neurosci 2016; 36:5084-93. [PMID: 27147660 PMCID: PMC6601857 DOI: 10.1523/jneurosci.0258-16.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 03/21/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The aggregation of amyloid-β peptide (Aβ) in brain is an early event and hallmark of Alzheimer's disease (AD). We combined the advantages of in vitro and in vivo approaches to study cerebral β-amyloidosis by establishing a long-term hippocampal slice culture (HSC) model. While no Aβ deposition was noted in untreated HSCs of postnatal Aβ precursor protein transgenic (APP tg) mice, Aβ deposition emerged in HSCs when cultures were treated once with brain extract from aged APP tg mice and the culture medium was continuously supplemented with synthetic Aβ. Seeded Aβ deposition was also observed under the same conditions in HSCs derived from wild-type or App-null mice but in no comparable way when HSCs were fixed before cultivation. Both the nature of the brain extract and the synthetic Aβ species determined the conformational characteristics of HSC Aβ deposition. HSC Aβ deposits induced a microglia response, spine loss, and neuritic dystrophy but no obvious neuron loss. Remarkably, in contrast to in vitro aggregated synthetic Aβ, homogenates of Aβ deposits containing HSCs induced cerebral β-amyloidosis upon intracerebral inoculation into young APP tg mice. Our results demonstrate that a living cellular environment promotes the seeded conversion of synthetic Aβ into a potent in vivo seeding-active form. SIGNIFICANCE STATEMENT In this study, we report the seeded induction of Aβ aggregation and deposition in long-term hippocampal slice cultures. Remarkably, we find that the biological activities of the largely synthetic Aβ aggregates in the culture are very similar to those observed in vivo This observation is the first to show that potent in vivo seeding-active Aβ aggregates can be obtained by seeded conversion of synthetic Aβ in a living (wild-type) cellular environment.
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Affiliation(s)
- Renata Novotny
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany, Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen D-72076, Germany
| | - Franziska Langer
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Jasmin Mahler
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany, Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen D-72076, Germany
| | - Angelos Skodras
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Andreas Vlachos
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt/Main D-60590, Germany
| | - Bettina M Wegenast-Braun
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Stephan A Kaeser
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Jonas J Neher
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Yvonne S Eisele
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Marie J Pietrowski
- Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg D-79104, Germany, and
| | - K Peter R Nilsson
- Department of Chemistry, IFM, Linköping University, Linköping SE-581 83, Sweden
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt/Main D-60590, Germany
| | - Matthias Staufenbiel
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany
| | - Bernd Heimrich
- Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg D-79104, Germany, and
| | - Mathias Jucker
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen D-72076, Germany, DZNE, German Center for Neurodegenerative Diseases, Tübingen D-72076, Germany,
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23
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Henjum K, Almdahl IS, Årskog V, Minthon L, Hansson O, Fladby T, Nilsson LNG. Cerebrospinal fluid soluble TREM2 in aging and Alzheimer's disease. Alzheimers Res Ther 2016; 8:17. [PMID: 27121148 PMCID: PMC4848774 DOI: 10.1186/s13195-016-0182-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/30/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) neuropathology is associated with neuroinflammation, but there are few useful biomarkers. Mutant variants of triggering receptor expressed on myeloid cells 2 (TREM2) have recently been linked to late-onset AD and other neurodegenerative disorders. TREM2, a microglial receptor, is involved in innate immunity. A cleaved fragment, soluble TREM2 (sTREM2), is present in the cerebrospinal fluid (CSF). METHODS We developed and used a novel enzyme-linked immunosorbent assay to investigate the potential value of CSF sTREM2 as an AD biomarker in two independent cohorts: an AD/mild cognitive impairment (MCI)/control cohort (n = 100) and an AD/control cohort (n = 50). RESULTS We found no significant difference in sTREM2 levels between groups of controls and patients with AD or MCI. However, among all controls there was a positive correlation between sTREM2 and age (Spearman rho = 0.50; p < 0.001; n = 75). In the AD/MCI/control cohort, CSF sTREM2 correlated positively with total Tau (T-tau) (Spearman rho 0.57; p < 0.001; n = 50), phosphorylated Tau (P-tau) (Spearman rho 0.63; p < 0.001; n = 50) and amyloid-β1-42 (Aβ42) (Spearman rho 0.35; p = 0.01; n = 50) in control subjects. Among controls with a CSF Aβ42 above a cut-off value (700 pg/ml) in this cohort, the positive correlation between sTREM2 and Aβ42 was stronger (Spearman rho = 0.44; p = 0.002; n = 46). CONCLUSIONS sTREM2 in CSF correlates with aging in controls, and with the neurodegenerative markers CSF T-tau/P-tau among controls who are negative for AD CSF core biomarkers Aβ42, T-tau or P-tau.
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Affiliation(s)
- Kristi Henjum
- />Department of Pharmacology, University of Oslo and Oslo University Hospital, P.b. 1057, Blindern NO-0316, Oslo, Norway
| | - Ina S. Almdahl
- />Department of Neurology, Akershus University Hospital, Lørenskog, Norway
- />Department of Neurology, Faculty Division, Akershus University Hospital, University of Oslo, Lørenskog, Norway
| | - Vibeke Årskog
- />Department of Pharmacology, University of Oslo and Oslo University Hospital, P.b. 1057, Blindern NO-0316, Oslo, Norway
| | - Lennart Minthon
- />Department of Clinical Sciences Malmö, Memory Clinic, Clinical Memory Research Unit, Lund University, Malmö, Sweden
| | - Oskar Hansson
- />Department of Clinical Sciences Malmö, Memory Clinic, Clinical Memory Research Unit, Lund University, Malmö, Sweden
| | - Tormod Fladby
- />Department of Neurology, Akershus University Hospital, Lørenskog, Norway
- />Department of Neurology, Faculty Division, Akershus University Hospital, University of Oslo, Lørenskog, Norway
| | - Lars N. G. Nilsson
- />Department of Pharmacology, University of Oslo and Oslo University Hospital, P.b. 1057, Blindern NO-0316, Oslo, Norway
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24
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Relevance of the COPI complex for Alzheimer's disease progression in vivo. Proc Natl Acad Sci U S A 2016; 113:5418-23. [PMID: 27114526 DOI: 10.1073/pnas.1604176113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cellular trafficking and recycling machineries belonging to late secretory compartments have been associated with increased Alzheimer's disease (AD) risk. We have shown that coat protein complex I (COPI)-dependent trafficking, an early step in Golgi-to-endoplasmic reticulum retrograde transport, affects amyloid precursor protein subcellular localization, cell-surface expression, as well as its metabolism. We present here a set of experiments demonstrating that, by targeting subunit δ-COP function, the moderation of the COPI-dependent trafficking in vivo leads to a significant decrease in amyloid plaques in the cortex and hippocampus of neurological 17 mice crossed with the 2xTg AD mouse model. Remarkably, an improvement of the memory impairments was also observed. Importantly, human genetic association studies of different AD cohorts led to the identification of 12 SNPs and 24 mutations located in COPI genes linked to an increased AD risk. These findings further demonstrate in vivo the importance of early trafficking steps in AD pathogenesis and open new clinical perspectives.
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25
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Hunter S, Martin S, Brayne C. The APP Proteolytic System and Its Interactions with Dynamic Networks in Alzheimer's Disease. Methods Mol Biol 2016; 1303:71-99. [PMID: 26235060 DOI: 10.1007/978-1-4939-2627-5_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Diseases of aging are often complex and multifactorial, involving many genetic and life course modifiers. Systems biology is becoming an essential tool to investigate disease initiation and disease progression. Alzheimer's disease (AD) can be used as a case study to investigate the application of systems biology to complex disease. Here we describe approaches to capturing biological data, representing data in terms of networks and interpreting their meaning in relation to the human population. We highlight issues that remain to be addressed both in terms of modeling disease progression and in relating findings to the current understanding of human disease.
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Affiliation(s)
- Sally Hunter
- Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge School of Clinical Medicine, Forvie Site, Cambridge Biomedical Campus, Box 113, Cambridge, CB2 0SP, UK,
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26
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Mahler J, Morales-Corraliza J, Stolz J, Skodras A, Radde R, Duma CC, Eisele YS, Mazzella MJ, Wong H, Klunk WE, Nilsson KPR, Staufenbiel M, Mathews PM, Jucker M, Wegenast-Braun BM. Endogenous murine Aβ increases amyloid deposition in APP23 but not in APPPS1 transgenic mice. Neurobiol Aging 2015; 36:2241-2247. [PMID: 25911278 DOI: 10.1016/j.neurobiolaging.2015.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 03/12/2015] [Accepted: 03/18/2015] [Indexed: 11/19/2022]
Abstract
Endogenous murine amyloid-β peptide (Aβ) is expressed in most Aβ precursor protein (APP) transgenic mouse models of Alzheimer's disease but its contribution to β-amyloidosis remains unclear. We demonstrate ∼ 35% increased cerebral Aβ load in APP23 transgenic mice compared with age-matched APP23 mice on an App-null background. No such difference was found for the much faster Aβ-depositing APPPS1 transgenic mouse model between animals with or without the murine App gene. Nevertheless, both APP23 and APPPS1 mice codeposited murine Aβ, and immunoelectron microscopy revealed a tight association of murine Aβ with human Aβ fibrils. Deposition of murine Aβ was considerably less efficient compared with the deposition of human Aβ indicating a lower amyloidogenic potential of murine Aβ in vivo. The amyloid dyes Pittsburgh Compound-B and pentamer formyl thiophene acetic acid did not differentiate between amyloid deposits consisting of human Aβ and deposits of mixed human-murine Aβ. Our data demonstrate a differential effect of murine Aβ on human Aβ deposition in different APP transgenic mice. The mechanistically complex interaction of human and mouse Aβ may affect pathogenesis of the models and should be considered when models are used for translational preclinical studies.
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Affiliation(s)
- Jasmin Mahler
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Jose Morales-Corraliza
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Julia Stolz
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany; Graduate School for Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Angelos Skodras
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Rebecca Radde
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Carmen C Duma
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Yvonne S Eisele
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Matthew J Mazzella
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Harrison Wong
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - William E Klunk
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - K Peter R Nilsson
- Department of Chemistry, IFM, Linköping University, Linköping, Sweden
| | - Matthias Staufenbiel
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Paul M Mathews
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Mathias Jucker
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany.
| | - Bettina M Wegenast-Braun
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen, Germany.
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27
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Clemen CS, Stöckigt F, Strucksberg KH, Chevessier F, Winter L, Schütz J, Bauer R, Thorweihe JM, Wenzel D, Schlötzer-Schrehardt U, Rasche V, Krsmanovic P, Katus HA, Rottbauer W, Just S, Müller OJ, Friedrich O, Meyer R, Herrmann H, Schrickel JW, Schröder R. The toxic effect of R350P mutant desmin in striated muscle of man and mouse. Acta Neuropathol 2015; 129:297-315. [PMID: 25394388 PMCID: PMC4309020 DOI: 10.1007/s00401-014-1363-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/14/2014] [Accepted: 10/30/2014] [Indexed: 01/09/2023]
Abstract
Mutations of the human desmin gene on chromosome 2q35 cause autosomal dominant, autosomal recessive and sporadic forms of protein aggregation myopathies and cardiomyopathies. We generated R349P desmin knock-in mice, which harbor the ortholog of the most frequently occurring human desmin missense mutation R350P. These mice develop age-dependent desmin-positive protein aggregation pathology, skeletal muscle weakness, dilated cardiomyopathy, as well as cardiac arrhythmias and conduction defects. For the first time, we report the expression level and subcellular distribution of mutant versus wild-type desmin in our mouse model as well as in skeletal muscle specimens derived from human R350P desminopathies. Furthermore, we demonstrate that the missense-mutant desmin inflicts changes of the subcellular localization and turnover of desmin itself and of direct desmin-binding partners. Our findings unveil a novel principle of pathogenesis, in which not the presence of protein aggregates, but disruption of the extrasarcomeric intermediate filament network leads to increased mechanical vulnerability of muscle fibers. These structural defects elicited at the myofiber level finally impact the entire organ and subsequently cause myopathy and cardiomyopathy.
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MESH Headings
- Animals
- Arrhythmias, Cardiac/pathology
- Arrhythmias, Cardiac/physiopathology
- Cardiomyopathies/pathology
- Cardiomyopathies/physiopathology
- Cardiomyopathy, Dilated/pathology
- Cardiomyopathy, Dilated/physiopathology
- Cytoskeleton/metabolism
- Cytoskeleton/pathology
- Desmin/genetics
- Desmin/metabolism
- Disease Models, Animal
- Escherichia coli
- Gene Knock-In Techniques
- Heart Ventricles/pathology
- Heart Ventricles/physiopathology
- Humans
- Mice, Transgenic
- Muscle Weakness/pathology
- Muscle Weakness/physiopathology
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Dystrophies/pathology
- Muscular Dystrophies/physiopathology
- Mutation, Missense
- Myocardium/pathology
- RNA, Messenger/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sf9 Cells
- Spodoptera
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Affiliation(s)
- Christoph S. Clemen
- Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
| | - Florian Stöckigt
- Department of Internal Medicine II, University Hospital Bonn, 53105 Bonn, Germany
| | - Karl-Heinz Strucksberg
- Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
- Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Frederic Chevessier
- Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Lilli Winter
- Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Johanna Schütz
- Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Ralf Bauer
- Department of Internal Medicine III, University Hospital Heidelberg, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | | | - Daniela Wenzel
- Institute of Physiology I, Life and Brain Center, University of Bonn, 53127 Bonn, Germany
| | | | - Volker Rasche
- Department of Internal Medicine II, University Hospital Ulm, 89081 Ulm, Germany
- Core Facility Small Animal Imaging, University of Ulm, 89081 Ulm, Germany
| | - Pavle Krsmanovic
- Functional Architecture of the Cell, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Hugo A. Katus
- Department of Internal Medicine III, University Hospital Heidelberg, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Wolfgang Rottbauer
- Department of Internal Medicine II, University Hospital Ulm, 89081 Ulm, Germany
| | - Steffen Just
- Department of Internal Medicine II, University Hospital Ulm, 89081 Ulm, Germany
| | - Oliver J. Müller
- Department of Internal Medicine III, University Hospital Heidelberg, 69120 Heidelberg, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, University of Erlangen, 91052 Erlangen, Germany
| | - Rainer Meyer
- Institute of Physiology II, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - Harald Herrmann
- Functional Architecture of the Cell, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Jan Wilko Schrickel
- Department of Internal Medicine II, University Hospital Bonn, 53105 Bonn, Germany
| | - Rolf Schröder
- Institute of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
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28
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Xu W, Fitzgerald S, Nixon RA, Levy E, Wilson DA. Early hyperactivity in lateral entorhinal cortex is associated with elevated levels of AβPP metabolites in the Tg2576 mouse model of Alzheimer's disease. Exp Neurol 2015; 264:82-91. [PMID: 25500142 PMCID: PMC4324092 DOI: 10.1016/j.expneurol.2014.12.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/14/2014] [Accepted: 12/07/2014] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder which is the most common cause of dementia in the elderly today. One of the earliest symptoms of AD is olfactory dysfunction. The present study investigated the effects of amyloid β precursor protein (AβPP) metabolites, including amyloid-β (Aβ) and AβPP C-terminal fragments (CTF), on olfactory processing in the lateral entorhinal cortex (LEC) using the Tg2576 mouse model of human AβPP over-expression. The entorhinal cortex is an early target of AD related neuropathology, and the LEC plays an important role in fine odor discrimination and memory. Cohorts of transgenic and age-matched wild-type (WT) mice at 3, 6, and 16months of age (MO) were anesthetized and acute, single-unit electrophysiology was performed in the LEC. Results showed that Tg2576 exhibited early LEC hyperactivity at 3 and 6MO compared to WT mice in both local field potential and single-unit spontaneous activity. However, LEC single-unit odor responses and odor receptive fields showed no detectable difference compared to WT at any age. Finally, the very early emergence of olfactory system hyper-excitability corresponded not to detectable Aβ deposition in the olfactory system, but rather to high levels of intracellular AβPP-CTF and soluble Aβ in the anterior piriform cortex (aPCX), a major afferent input to the LEC, by 3MO. The present results add to the growing evidence of AβPP-related hyper-excitability, and further implicate both soluble Aβ and non-Aβ AβPP metabolites in its early emergence.
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Affiliation(s)
- Wenjin Xu
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Child & Adolescent Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Shane Fitzgerald
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Donald A Wilson
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Child & Adolescent Psychiatry, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA.
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29
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Schafer MJ, Alldred MJ, Lee SH, Calhoun ME, Petkova E, Mathews PM, Ginsberg SD. Reduction of β-amyloid and γ-secretase by calorie restriction in female Tg2576 mice. Neurobiol Aging 2014; 36:1293-302. [PMID: 25556162 DOI: 10.1016/j.neurobiolaging.2014.10.043] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 09/22/2014] [Accepted: 10/07/2014] [Indexed: 12/21/2022]
Abstract
Research indicates that female risk of developing Alzheimer's disease (AD) is greater than that of males. Moderate reduction of calorie intake, known as calorie restriction (CR), reduces pathology in AD mouse models and is a potentially translatable prevention measure for individuals at-risk for AD, as well as an important tool for understanding how the brain endogenously attenuates age-related pathology. Whether sex influences the response to CR remains unknown. In this study, we assessed the effect of CR on beta-amyloid peptide (Aβ) pathology and hippocampal CA1 neuron specific gene expression in the Tg2576 mouse model of cerebral amyloidosis. Relative to ad libitum (AL) feeding, CR feeding significantly reduced hippocampal Aβ burden in 15-month-old female, but not age-matched male, Tg2576 mice. Sustained CR also significantly reduced expression of presenilin enhancer 2 (Psenen) and presenilin 1, components of the γ-secretase complex, in Tg2576 females. These results indicate that long-term CR significantly reduces age-dependent female Tg2576 Aβ pathology, which is likely to involve CR-mediated reductions in γ-secretase-dependent amyloid precursor protein (APP) metabolism.
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Affiliation(s)
- Marissa J Schafer
- Cell and Molecular Biology Program, New York University Langone Medical Center, New York, NY, USA; Department of Cell Biology, New York University Langone Medical Center, New York, NY, USA; Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Sang Han Lee
- Division of Medical Physics, Nathan Kline Institute, Orangeburg, NY, USA
| | | | - Eva Petkova
- Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA; Division of Child Psychiatry, Nathan Kline Institute, Orangeburg, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Stephen D Ginsberg
- Cell and Molecular Biology Program, New York University Langone Medical Center, New York, NY, USA; Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA; Department of Physiology & Neuroscience, New York University Langone Medical Center, New York, NY, USA.
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30
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Yan Y, Eipper BA, Mains RE. Kalirin-9 and Kalirin-12 Play Essential Roles in Dendritic Outgrowth and Branching. Cereb Cortex 2014; 25:3487-501. [PMID: 25146373 DOI: 10.1093/cercor/bhu182] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Proteins derived from the Kalrn gene, encoding 2 Rho guanine nucleotide exchange factor (GEF) domains, affect dendritic and axonal morphogenesis. The roles of endogenous Kalirin-9 (Kal9) and Kalirin-12 (Kal12), the Kalrn isoforms expressed before synaptogenesis, have not been studied in neurite growth and maturation during early development. The Caenorhabditis elegans and Drosophila melanogaster orthologues of Kalrn encode proteins equivalent to Kal9 but, lacking a kinase domain, neither organism expresses a protein equivalent to Kal12. Both in vivo and in vitro analyses of cortical neurons from total Kalrn knockout mice, lacking all major Kalirin isoforms, revealed a simplified dendritic arbor and reduced neurite length. Using isoform-specific shRNAs to reduce Kal9 or Kal12 expression in hippocampal cultures resulted in stunted dendritic outgrowth and branching in vitro, without affecting axonal polarity. Exposing hippocampal cultures to inhibitors of the first GEF domain of Kalirin (ITX3, Z62954982) blunted neurite outgrowth and branching, confirming its essential role, without altering the morphology of neurons not expressing Kalrn. In addition, exogenous expression of the active kinase domain unique to Kal12 increased neurite number and length, whereas that of the inactive kinase domain decreased neurite growth. Our results demonstrate that both endogenous Kal9 and endogenous Kal12 contribute to dendritic maturation in early development.
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Affiliation(s)
- Yan Yan
- Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Betty A Eipper
- Department of Neuroscience, UConn Health, Farmington, CT 06030, USA Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030, USA
| | - Richard E Mains
- Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
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Duffy AM, Morales-Corraliza J, Bermudez-Hernandez KM, Schaner MJ, Magagna-Poveda A, Mathews PM, Scharfman HE. Entorhinal cortical defects in Tg2576 mice are present as early as 2-4 months of age. Neurobiol Aging 2014; 36:134-48. [PMID: 25109765 DOI: 10.1016/j.neurobiolaging.2014.07.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 11/15/2022]
Abstract
The entorhinal cortex (EC) is one of the first brain areas to display neuropathology in Alzheimer's disease. A mouse model which simulates amyloid-β (Aβ) neuropathology, the Tg2576 mouse, was used to address these early changes. Here, we show EC abnormalities occur in 2- to 4-month-old Tg2576 mice, an age before Aβ deposition and where previous studies suggest that there are few behavioral impairments. First we show, using a sandwich enzyme-linked immunosorbent assay, that soluble human Aβ40 and Aβ42 are detectable in the EC of 2-month-old Tg2576 mice before Aβ deposition. We then demonstrate that 2- to 4-month-old Tg2576 mice are impaired at object placement, an EC-dependent cognitive task. Next, we show that defects in neuronal nuclear antigen expression and myelin uptake occur in the superficial layers of the EC in 2- to 4-month-old Tg2576 mice. In slices from Tg2576 mice that contained the EC, there were repetitive field potentials evoked by a single stimulus to the underlying white matter, and a greater response to reduced extracellular magnesium ([Mg(2+)]o), suggesting increased excitability. However, deep layer neurons in Tg2576 mice had longer latencies to antidromic activation than wild type mice. The results show changes in the EC at early ages and suggest that altered excitability occurs before extensive plaque pathology.
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Affiliation(s)
- Aine M Duffy
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Child & Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA.
| | - Jose Morales-Corraliza
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Keria M Bermudez-Hernandez
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Physiology & Neuroscience, Sackler Institute of Graduate Biomedical Sciences, New York University Langone Medical Center, New York, NY, USA
| | - Michael J Schaner
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA
| | - Alejandra Magagna-Poveda
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Child & Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA; Department of Physiology & Neuroscience, New York University Langone Medical Center, New York, NY, USA
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32
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Hunter S, Brayne C. Integrating the molecular and the population approaches to dementia research to help guide the future development of appropriate therapeutics. Biochem Pharmacol 2014; 88:652-60. [DOI: 10.1016/j.bcp.2013.12.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 12/18/2013] [Accepted: 12/18/2013] [Indexed: 12/13/2022]
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33
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Weyer SW, Zagrebelsky M, Herrmann U, Hick M, Ganss L, Gobbert J, Gruber M, Altmann C, Korte M, Deller T, Müller UC. Comparative analysis of single and combined APP/APLP knockouts reveals reduced spine density in APP-KO mice that is prevented by APPsα expression. Acta Neuropathol Commun 2014; 2:36. [PMID: 24684730 PMCID: PMC4023627 DOI: 10.1186/2051-5960-2-36] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 11/21/2022] Open
Abstract
Synaptic dysfunction and synapse loss are key features of Alzheimer's pathogenesis. Previously, we showed an essential function of APP and APLP2 for synaptic plasticity, learning and memory. Here, we used organotypic hippocampal cultures to investigate the specific role(s) of APP family members and their fragments for dendritic complexity and spine formation of principal neurons within the hippocampus. Whereas CA1 neurons from APLP1-KO or APLP2-KO mice showed normal neuronal morphology and spine density, APP-KO mice revealed a highly reduced dendritic complexity in mid-apical dendrites. Despite unaltered morphology of APLP2-KO neurons, combined APP/APLP2-DKO mutants showed an additional branching defect in proximal apical dendrites, indicating redundancy and a combined function of APP and APLP2 for dendritic architecture. Remarkably, APP-KO neurons showed a pronounced decrease in spine density and reductions in the number of mushroom spines. No further decrease in spine density, however, was detectable in APP/APLP2-DKO mice. Mechanistically, using APPsα-KI mice lacking transmembrane APP and expressing solely the secreted APPsα fragment we demonstrate that APPsα expression alone is sufficient to prevent the defects in spine density observed in APP-KO mice. Collectively, these studies reveal a combined role of APP and APLP2 for dendritic architecture and a unique function of secreted APPs for spine density.
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Affiliation(s)
- Sascha W Weyer
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
| | - Marta Zagrebelsky
- TU Braunschweig, Zoological Institute, Cellular Neurobiology, Spielmannstr. 7, Braunschweig D-38106, Germany
| | - Ulrike Herrmann
- TU Braunschweig, Zoological Institute, Cellular Neurobiology, Spielmannstr. 7, Braunschweig D-38106, Germany
| | - Meike Hick
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
| | - Lennard Ganss
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
- Present address: Department of Applied Tumor Biology, Ruprecht-Karls University Heidelberg, Institute of Pathology, University of Heidelberg, Heidelberg D-69120, Germany
| | - Julia Gobbert
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
| | - Morna Gruber
- Goethe University Frankfurt, Institute of Clinical Neuroanatomy, Neuroscience Center, Theodor-Stern-Kai 7, Frankfurt am Main D-60596, Germany
| | - Christine Altmann
- Goethe University Frankfurt, Institute of Clinical Neuroanatomy, Neuroscience Center, Theodor-Stern-Kai 7, Frankfurt am Main D-60596, Germany
| | - Martin Korte
- TU Braunschweig, Zoological Institute, Cellular Neurobiology, Spielmannstr. 7, Braunschweig D-38106, Germany
| | - Thomas Deller
- Goethe University Frankfurt, Institute of Clinical Neuroanatomy, Neuroscience Center, Theodor-Stern-Kai 7, Frankfurt am Main D-60596, Germany
| | - Ulrike C Müller
- Department of Bioinformatics and Functional Genomics, Ruprecht-Karls University Heidelberg, Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 364, Heidelberg D-69120, Germany
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34
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Atkin G, Hunt J, Minakawa E, Sharkey L, Tipper N, Tennant W, Paulson HL. F-box only protein 2 (Fbxo2) regulates amyloid precursor protein levels and processing. J Biol Chem 2014; 289:7038-7048. [PMID: 24469452 DOI: 10.1074/jbc.m113.515056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The amyloid precursor protein (APP) is an integral membrane glycoprotein whose cleavage products, particularly amyloid-β, accumulate in Alzheimer disease (AD). APP is present at synapses and is thought to play a role in both the formation and plasticity of these critical neuronal structures. Despite the central role suggested for APP in AD pathogenesis, the mechanisms regulating APP in neurons and its processing into cleavage products remain incompletely understood. F-box only protein 2 (Fbxo2), a neuron-enriched ubiquitin ligase substrate adaptor that preferentially binds high-mannose glycans on glycoproteins, was previously implicated in APP processing by facilitating the degradation of the APP-cleaving β-secretase, β-site APP-cleaving enzyme. Here, we sought to determine whether Fbxo2 plays a similar role for other glycoproteins in the amyloid processing pathway. We present in vitro and in vivo evidence that APP is itself a substrate for Fbxo2. APP levels were decreased in the presence of Fbxo2 in non-neuronal cells, and increased in both cultured hippocampal neurons and brain tissue from Fbxo2 knock-out mice. The processing of APP into its cleavage products was also increased in hippocampi and cultured hippocampal neurons lacking Fbxo2. In hippocampal slices, this increase in cleavage products was accompanied by a significant reduction in APP at the cell surface. Taken together, these results suggest that Fbxo2 regulates APP levels and processing in the brain and may play a role in modulating AD pathogenesis.
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Affiliation(s)
- Graham Atkin
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104.
| | - Jack Hunt
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104
| | - Eiko Minakawa
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104
| | - Lisa Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104
| | - Nathan Tipper
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104
| | - William Tennant
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48104.
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35
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Choi JHK, Kaur G, Mazzella MJ, Morales-Corraliza J, Levy E, Mathews PM. Early endosomal abnormalities and cholinergic neuron degeneration in amyloid-β protein precursor transgenic mice. J Alzheimers Dis 2013; 34:691-700. [PMID: 23254640 DOI: 10.3233/jad-122143] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Early endosomal changes, a prominent pathology in neurons early in Alzheimer's disease, also occur in neurons and peripheral tissues in Down syndrome. While in Down syndrome models increased amyloid-β protein precursor (AβPP) expression is known to be a necessary contributor on the trisomic background to this early endosomal pathology, increased AβPP alone has yet to be shown to be sufficient to drive early endosomal alterations in neurons. Comparing two AβPP transgenic mouse models, one that contains the AβPP Swedish K670N/M671L double mutation at the β-cleavage site (APP23) and one that has the AβPP London V717I mutation near the γ-cleavage site (APPLd2), we show significantly altered early endosome morphology in fronto-parietal neurons as well as enlargement of early endosomes in basal forebrain cholinergic neurons of the medial septal nucleus in the APP23 model, which has the higher levels of AβPP β-C-terminal fragment (βCTF) accumulation. Early endosomal changes correlate with a marked loss of the cholinergic population, which is consistent with the known dependence of the large projection cholinergic cells on endosome-mediated retrograde neurotrophic transport. Our findings support the idea that increased expression of AβPP and AβPP metabolites in neurons is sufficient to drive early endosomal abnormalities in vivo, and that disruption of the endocytic system is likely to contribute to basal forebrain cholinergic vulnerability.
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36
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Arun P, Abu-Taleb R, Oguntayo S, Tanaka M, Wang Y, Valiyaveettil M, Long JB, Zhang Y, Nambiar MP. Distinct patterns of expression of traumatic brain injury biomarkers after blast exposure: Role of compromised cell membrane integrity. Neurosci Lett 2013; 552:87-91. [DOI: 10.1016/j.neulet.2013.07.047] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/17/2013] [Accepted: 07/27/2013] [Indexed: 10/26/2022]
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37
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Huang Y, Li T, Eatherton A, Mitchell WL, Rong N, Ye L, Yang XJ, Jin S, Ding Y, Zhang J, Li Y, Wu Y, Jin Y, Sang Y, Cheng Z, Browne ER, Harrison DC, Hussain I, Wan Z, Hall A, Lau LF, Matsuoka Y. Orally bioavailable and brain-penetrant pyridazine and pyridine-derived γ-secretase modulators reduced amyloidogenic Aβ peptides in vivo. Neuropharmacology 2013; 70:278-86. [DOI: 10.1016/j.neuropharm.2013.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 12/27/2012] [Accepted: 02/06/2013] [Indexed: 12/31/2022]
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38
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Abstract
Biochemical and genetic evidence establishes a central role of the amyloid precursor protein (APP) in Alzheimer disease (AD) pathogenesis. Biochemically, deposition of the β-amyloid (Aβ) peptides produced from proteolytic processing of APP forms the defining pathological hallmark of AD; genetically, both point mutations and duplications of wild-type APP are linked to a subset of early onset of familial AD (FAD) and cerebral amyloid angiopathy. As such, the biological functions of APP and its processing products have been the subject of intense investigation, and the past 20+ years of research have met with both excitement and challenges. This article will review the current understanding of the physiological functions of APP in the context of APP family members.
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Affiliation(s)
- Ulrike C Müller
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Germany.
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39
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Teich AF, Patel M, Arancio O. A reliable way to detect endogenous murine β-amyloid. PLoS One 2013; 8:e55647. [PMID: 23383341 PMCID: PMC3562188 DOI: 10.1371/journal.pone.0055647] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 12/31/2012] [Indexed: 01/09/2023] Open
Abstract
Unraveling the normal physiologic role of β-amyloid is likely crucial to understanding the pathogenesis of Alzheimer's disease. However, progress on this question is currently limited by the high background of many ELISAs for murine β-amyloid. Here, we examine the background signal of several murine β-amyloid ELISAs, and conclude that the majority of the background is from non-APP derived proteins. Most importantly, we identify ELISAs that eliminate this background signal.
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Affiliation(s)
- Andrew F Teich
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America.
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40
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Wesson DW, Morales-Corraliza J, Mazella MJ, Wilson DA, Mathews PM. Chronic anti-murine Aβ immunization preserves odor guided behaviors in an Alzheimer's β-amyloidosis model. Behav Brain Res 2013; 237:96-102. [PMID: 23000537 PMCID: PMC3500395 DOI: 10.1016/j.bbr.2012.09.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/11/2012] [Accepted: 09/14/2012] [Indexed: 01/07/2023]
Abstract
Olfaction is often impaired in Alzheimer's disease (AD) and is also dysfunctional in mouse models of the disease. We recently demonstrated that short-term passive anti-murine-Aβ immunization can rescue olfactory behavior in the Tg2576 mouse model overexpressing a human mutation of the amyloid precursor protein (APP) after β-amyloid deposition. Here we tested the ability to preserve normal olfactory behaviors by means of long-term passive anti-murine-Aβ immunization. Seven-month-old Tg2576 and non-transgenic littermate (NTg) mice were IP-injected biweekly with the m3.2 murine-Aβ-specific antibody until 16 mo of age when mice were tested in the odor habituation test. While Tg2576 mice treated with a control antibody showed elevations in odor investigation times and impaired odor habituation compared to NTg, olfactory behavior was preserved to NTg levels in m3.2-immunized Tg2576 mice. Immunized Tg2576 mice had significantly less β-amyloid immunolabeling in the olfactory bulb and entorhinal cortex, yet showed elevations in Thioflavin-S labeled plaques in the piriform cortex. No detectable changes in APP metabolite levels other than Aβ were found following m3.2 immunization. These results demonstrate efficacy of chronic, long-term anti-murine-Aβ m3.2 immunization in preserving normal odor-guided behaviors in a human APP Tg model. Further, these results provide mechanistic insights into olfactory dysfunction as a biomarker for AD by yielding evidence that focal reductions of Aβ may be sufficient to preserve olfaction.
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Affiliation(s)
- Daniel W. Wesson
- Emotional Brain Institute Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY, 10962
- Department of Child & Adolescent Psychiatry New York University School of Medicine New York, NY, 10016
| | - Jose Morales-Corraliza
- Center for Dementia Research Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY, 10962
- Department of Psychiatry New York University School of Medicine New York, NY, 10016
| | - Matthew J. Mazella
- Center for Dementia Research Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY, 10962
| | - Donald A. Wilson
- Emotional Brain Institute Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY, 10962
- Department of Child & Adolescent Psychiatry New York University School of Medicine New York, NY, 10016
- Center for Neural Science New York University New York, NY, 10003
| | - Paul M. Mathews
- Center for Dementia Research Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY, 10962
- Department of Psychiatry New York University School of Medicine New York, NY, 10016
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41
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Abstract
Despite tremendous investments in understanding the complex molecular mechanisms underlying Alzheimer disease (AD), recent clinical trials have failed to show efficacy. A potential problem underlying these failures is the assumption that the molecular mechanism mediating the genetically determined form of the disease is identical to the one resulting in late-onset AD. Here, we integrate experimental evidence outside the 'spotlight' of the genetic drivers of amyloid-β (Aβ) generation published during the past two decades, and present a mechanistic explanation for the pathophysiological changes that characterize late-onset AD. We propose that chronic inflammatory conditions cause dysregulation of mechanisms to clear misfolded or damaged neuronal proteins that accumulate with age, and concomitantly lead to tau-associated impairments of axonal integrity and transport. Such changes have several neuropathological consequences: focal accumulation of mitochondria, resulting in metabolic impairments; induction of axonal swelling and leakage, followed by destabilization of synaptic contacts; deposition of amyloid precursor protein in swollen neurites, and generation of aggregation-prone peptides; further tau hyperphosphorylation, ultimately resulting in neurofibrillary tangle formation and neuronal death. The proposed sequence of events provides a link between Aβ and tau-related neuropathology, and underscores the concept that degenerating neurites represent a cause rather than a consequence of Aβ accumulation in late-onset AD.
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42
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Morales-Corraliza J, Schmidt SD, Mazzella MJ, Berger JD, Wilson DA, Wesson DW, Jucker M, Levy E, Nixon RA, Mathews PM. Immunization targeting a minor plaque constituent clears β-amyloid and rescues behavioral deficits in an Alzheimer's disease mouse model. Neurobiol Aging 2012; 34:137-45. [PMID: 22608241 DOI: 10.1016/j.neurobiolaging.2012.04.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/30/2012] [Accepted: 04/15/2012] [Indexed: 01/01/2023]
Abstract
Although anti-human β-amyloid (Aβ) immunotherapy clears brain β-amyloid plaques in Alzheimer's disease (AD), targeting additional brain plaque constituents to promote clearance has not been attempted. Endogenous murine Aβ is a minor Aβ plaque component in amyloid precursor protein (APP) transgenic AD models, which we show is ∼3%-8% of the total accumulated Aβ in various human APP transgenic mice. Murine Aβ codeposits and colocalizes with human Aβ in amyloid plaques, and the two Aβ species coimmunoprecipitate together from brain extracts. In the human APP transgenic mouse model Tg2576, passive immunization for 8 weeks with a murine-Aβ-specific antibody reduced β-amyloid plaque pathology, robustly decreasing both murine and human Aβ levels. The immunized mice additionally showed improvements in two behavioral assays, odor habituation and nesting behavior. We conclude that passive anti-murine Aβ immunization clears Aβ plaque pathology--including the major human Aβ component--and decreases behavioral deficits, arguing that targeting minor endogenous brain plaque constituents can be beneficial, broadening the range of plaque-associated targets for AD therapeutics.
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Affiliation(s)
- Jose Morales-Corraliza
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
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43
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Hunter S, Brayne C. Relationships between the amyloid precursor protein and its various proteolytic fragments and neuronal systems. Alzheimers Res Ther 2012; 4:10. [PMID: 22498202 PMCID: PMC3583130 DOI: 10.1186/alzrt108] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease and in its familial form is associated with mutations in the amyloid precursor protein (APP) and the presenilins (PSs). Much data regarding the interactions of APP, its proteolytic fragments and PS have been generated, expanding our understanding of the roles of these proteins in mechanisms underlying cognitive function and revealing many complex relationships with wide ranging cellular systems. In this review, we examine the multiple interactions of APP and its proteolytic fragments with other neuronal systems in terms of feedback loops and use these relationships to build a map. We highlight the complexity involved in the APP proteolytic system and discuss alternative perspectives on the roles of APP and its proteolytic fragments in dynamic processes associated with disease progression in AD. We highlight areas where data are missing and suggest potential confounding factors. We suggest that a systems biology approach enhances representations of the data and may be more useful in modelling both normal cognition and disease processes.
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Affiliation(s)
- Sally Hunter
- Institute of Public Health, University of Cambridge, Forvie site, Robinson Way, Cambridge CB2 0SR, UK
| | - Carol Brayne
- Institute of Public Health, University of Cambridge, Forvie site, Robinson Way, Cambridge CB2 0SR, UK
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44
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Li T, Huang Y, Jin S, Ye L, Rong N, Yang X, Ding Y, Cheng Z, Zhang J, Wan Z, Harrison DC, Hussain I, Hall A, Lee DHS, Lau LF, Matsuoka Y. Γ-secretase modulators do not induce Aβ-rebound and accumulation of β-C-terminal fragment. J Neurochem 2012; 121:277-86. [PMID: 22035227 DOI: 10.1111/j.1471-4159.2011.07560.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
γ-secretase inhibitors (GSIs) have been developed to reduce amyloid-β (Aβ) production for the treatment of Alzheimer's disease by inhibiting the cleavage of amyloid precursor protein (APP). However, cross-inhibitory activity on the processing of Notch can cause adverse reactions. To avoid these undesirable effects, γ-secretase modulators (GSMs) are being developed to selectively reduce toxic Aβ production without perturbing Notch signaling. As it is also known that GSIs can cause a paradoxical increase of plasma Aβ over the baseline after a transient reduction (known as Aβ-rebound), we asked if GSMs would cause a similar rebound and what the potential mechanism might be. Our studies were performed with one GSI (LY-450139) and two chemically distinct GSMs. Although LY-450139 caused Aβ-rebound as expected in rat plasma, the two GSMs did not. Inhibition of APP processing by LY-450139 induced an accumulation of γ-secretase substrates, α- and β-C-terminal fragments of APP, but neither GSM caused such an accumulation. In conclusion, we discover that GSMs, unlike GSIs, do not cause Aβ-rebound, possibly because of the lack of accumulation of β-C-terminal fragments. GSMs may be superior to GSIs in the treatment of Alzheimer's disease not only by sparing Notch signaling but also by avoiding Aβ-rebound.
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Affiliation(s)
- Ting Li
- Neurodegeneration Research, R&D China, GlaxoSmithKline, Shanghai, China
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45
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Schmidt SD, Mazzella MJ, Nixon RA, Mathews PM. Aβ measurement by enzyme-linked immunosorbent assay. Methods Mol Biol 2012; 849:507-527. [PMID: 22528112 DOI: 10.1007/978-1-61779-551-0_34] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The neuritic plaque in the brain of Alzheimer's disease patients consists of an amyloid composed primarily of Aβ, an approximately 4-kDa peptide derived from the amyloid precursor protein. Multiple lines of evidence suggest that Aβ plays a key role in the pathogenesis of the disease, and potential treatments that target Aβ production and/or Aβ accumulation in the brain as β-amyloid are being aggressively pursued. Methods to quantitate the Aβ peptide are, therefore, invaluable to most studies aimed at a better understanding of the molecular etiology of the disease and in assessing potential therapeutics. Although other techniques have been used to measure Aβ in the brains of AD patients and β-amyloid-depositing transgenic mice, the enzyme-linked immunosorbent assay (ELISA) is one of the most commonly used, reliable, and sensitive methods for quantitating the Aβ peptide. Here we describe methods for the recovery of both soluble and deposited Aβ from brain tissue and the subsequent quantitation of the peptide by sandwich ELISA.
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Affiliation(s)
- Stephen D Schmidt
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
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46
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Tissue processing prior to analysis of Alzheimer's disease associated proteins and metabolites, including Aβ. Methods Mol Biol 2012; 849:493-506. [PMID: 22528111 DOI: 10.1007/978-1-61779-551-0_33] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Amyloid-containing tissue, whether from human patients or an animal model of a disease, is typically characterized by various biochemical and immunohistochemical techniques, many of which are described in detail in this volume. In this chapter, we describe a straightforward technique for the homogenization of tissue prior to these analyses. The technique is particularly well suited for performing a large number of different biochemical analyses on a single mouse brain hemisphere. Starting with this homogenate multiple characterizations can be done, including western blot analysis and isolation of membrane-associated proteins, both of which are described here. Additional analyses can readily be performed on the tissue homogenate, including the ELISA quantitation of Aβ in the brain of a transgenic mouse model of β-amyloid deposition. The ELISA technique is described in detail in Chapter 34.
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47
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Morales-Corraliza J, Berger JD, Mazzella MJ, Veeranna, Neubert TA, Ghiso J, Rao MV, Staufenbiel M, Nixon RA, Mathews PM. Calpastatin modulates APP processing in the brains of β-amyloid depositing but not wild-type mice. Neurobiol Aging 2011; 33:1125.e9-18. [PMID: 22206846 DOI: 10.1016/j.neurobiolaging.2011.11.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 11/15/2011] [Accepted: 11/20/2011] [Indexed: 11/27/2022]
Abstract
We report that neuronal overexpression of the endogenous inhibitor of calpains, calpastatin (CAST), in a mouse model of human Alzheimer's disease (AD) β-amyloidosis, the APP23 mouse, reduces β-amyloid (Aβ) pathology and Aβ levels when comparing aged, double transgenic (tg) APP23/CAST with APP23 mice. Concurrent with Aβ plaque deposition, aged APP23/CAST mice show a decrease in the steady-state brain levels of the amyloid precursor protein (APP) and APP C-terminal fragments (CTFs) when compared with APP23 mice. This CAST-dependent decrease in APP metabolite levels was not observed in single tg CAST mice expressing endogenous APP or in younger, Aβ plaque predepositing APP23/CAST mice. We also determined that the CAST-mediated inhibition of calpain activity in the brain is greater in the CAST mice with Aβ pathology than in non-APP tg mice, as demonstrated by a decrease in calpain-mediated cytoskeleton protein cleavage. Moreover, aged APP23/CAST mice have reduced extracellular signal-regulated kinase 1/2 (ERK1/2) activity and tau phosphorylation when compared with APP23 mice. In summary, in vivo calpain inhibition mediated by CAST transgene expression reduces Aβ pathology in APP23 mice, with our findings further suggesting that APP metabolism is modified by CAST overexpression as the mice develop Aβ pathology. Our results indicate that the calpain system in neurons is more responsive to CAST inhibition under conditions of Aβ pathology, suggesting that in the disease state neurons may be more sensitive to the therapeutic use of calpain inhibitors.
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Roesli C, Fugmann T, Borgia B, Schliemann C, Neri D, Jucker M. The accessible cerebral vascular proteome in a mouse model of cerebral β-amyloidosis. J Proteomics 2011; 74:539-46. [DOI: 10.1016/j.jprot.2011.01.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 01/12/2011] [Accepted: 01/12/2011] [Indexed: 12/14/2022]
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Glial fibrillary tangles and JAK/STAT-mediated glial and neuronal cell death in a Drosophila model of glial tauopathy. J Neurosci 2011; 30:16102-13. [PMID: 21123557 DOI: 10.1523/jneurosci.2491-10.2010] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A subset of neurodegenerative tauopathies is characterized by abundant filamentous inclusions of hyperphosphorylated tau in both neurons and glia. Although the contribution of neuronal tau to behavioral changes and neuronal loss in neurodegenerative diseases has been studied extensively, the functional consequences of tau deposition in glial cells have been less well characterized. To investigate the role of abnormal tau accumulation and aggregation in glial cells, we created a Drosophila model of glial tauopathy by expressing human wild-type tau in adult fly glial cells. Glial expression of tau resulted in robust aggregation of phosphorylated tau into fibrillary inclusions similar to human glial tangles. Tangle formation was accompanied by shortened lifespan and age-dependent apoptotic cell death of both glia and neurons. Genetic manipulation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling modified toxicity of glial tau. We also identified a synergistic interaction of combined tau expression in neurons and glial cells. In summary, we present a genetically tractable model of glial fibrillary tau tangle formation and identify JAK/STAT signaling as mediating the death of both glia and neurons in this model.
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