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Pensalfini A, Kim S, Subbanna S, Bleiwas C, Goulbourne CN, Stavrides PH, Jiang Y, Lee JH, Darji S, Pawlik M, Huo C, Peddy J, Berg MJ, Smiley JF, Basavarajappa BS, Nixon RA. Endosomal Dysfunction Induced by Directly Overactivating Rab5 Recapitulates Prodromal and Neurodegenerative Features of Alzheimer's Disease. Cell Rep 2020; 33:108420. [PMID: 33238112 DOI: 10.1016/j.celrep.2020.108420] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/05/2020] [Accepted: 11/02/2020] [Indexed: 12/11/2022] Open
Abstract
Neuronal endosomal dysfunction, the earliest known pathobiology specific to Alzheimer's disease (AD), is mediated by the aberrant activation of Rab5 triggered by APP-β secretase cleaved C-terminal fragment (APP-βCTF). To distinguish pathophysiological consequences specific to overactivated Rab5 itself, we activate Rab5 independently from APP-βCTF in the PA-Rab5 mouse model. We report that Rab5 overactivation alone recapitulates diverse prodromal and degenerative features of AD. Modest neuron-specific transgenic Rab5 expression inducing hyperactivation of Rab5 comparable to that in AD brain reproduces AD-related Rab5-endosomal enlargement and mistrafficking, hippocampal synaptic plasticity deficits via accelerated AMPAR endocytosis and dendritic spine loss, and tau hyperphosphorylation via activated glycogen synthase kinase-3β. Importantly, Rab5-mediated endosomal dysfunction induces progressive cholinergic neurodegeneration and impairs hippocampal-dependent memory. Aberrant neuronal Rab5-endosome signaling, therefore, drives a pathogenic cascade distinct from β-amyloid-related neurotoxicity, which includes prodromal and neurodegenerative features of AD, and suggests Rab5 overactivation as a potential therapeutic target.
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Affiliation(s)
- Anna Pensalfini
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA
| | - Seonil Kim
- Colorado State University, Department of Biomedical Sciences, Fort Collins, CO 80523, USA; Cellular and Molecular Biology Training Program, New York University Langone Health, New York, NY 10003, USA
| | - Shivakumar Subbanna
- Department of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Cynthia Bleiwas
- Department of Neurochemistry, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Chris N Goulbourne
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Philip H Stavrides
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Ying Jiang
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA
| | - Ju-Hyun Lee
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA
| | - Sandipkumar Darji
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Monika Pawlik
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Chunfeng Huo
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - James Peddy
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Martin J Berg
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - John F Smiley
- Department of Neurochemistry, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Balapal S Basavarajappa
- Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; Department of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; New York State Psychiatric Institute, New York, NY 10032, USA; Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; Department of Cell Biology, New York University Langone Health, New York, NY 10003, USA; NYU Neuroscience Institute, New York, NY 10003, USA.
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52
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Chen XQ, Salehi A, Pearn ML, Overk C, Nguyen PD, Kleschevnikov AM, Maccecchini M, Mobley WC. Targeting increased levels of APP in Down syndrome: Posiphen-mediated reductions in APP and its products reverse endosomal phenotypes in the Ts65Dn mouse model. Alzheimers Dement 2020; 17:271-292. [PMID: 32975365 PMCID: PMC7984396 DOI: 10.1002/alz.12185] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/07/2020] [Indexed: 12/20/2022]
Abstract
Objective Recent clinical trials targeting amyloid beta (Aβ) and tau in Alzheimer's disease (AD) have yet to demonstrate efficacy. Reviewing the hypotheses for AD pathogenesis and defining possible links between them may enhance insights into both upstream initiating events and downstream mechanisms, thereby promoting discovery of novel treatments. Evidence that in Down syndrome (DS), a population markedly predisposed to develop early onset AD, increased APP gene dose is necessary for both AD neuropathology and dementia points to normalization of the levels of the amyloid precursor protein (APP) and its products as a route to further define AD pathogenesis and discovering novel treatments. Background AD and DS share several characteristic manifestations. DS is caused by trisomy of whole or part of chromosome 21; this chromosome contains about 233 protein‐coding genes, including APP. Recent evidence points to a defining role for increased expression of the gene for APP and for its 99 amino acid C‐terminal fragment (C99, also known as β‐CTF) in dysregulating the endosomal/lysosomal system. The latter is critical for normal cellular function and in neurons for transmitting neurotrophic signals. New/updated hypothesis We hypothesize that the increase in APP gene dose in DS initiates a process in which increased levels of full‐length APP (fl‐APP) and its products, including β‐CTF and possibly Aβ peptides (Aβ42 and Aβ40), drive AD pathogenesis through an endosome‐dependent mechanism(s), which compromises transport of neurotrophic signals. To test this hypothesis, we carried out studies in the Ts65Dn mouse model of DS and examined the effects of Posiphen, an orally available small molecule shown in prior studies to reduce fl‐APP. In vitro, Posiphen lowered fl‐APP and its C‐terminal fragments, reversed Rab5 hyperactivation and early endosome enlargement, and restored retrograde transport of neurotrophin signaling. In vivo, Posiphen treatment (50 mg/kg/d, 26 days, intraperitoneal [i.p.]) of Ts65Dn mice was well tolerated and demonstrated no adverse effects in behavior. Treatment resulted in normalization of the levels of fl‐APP, C‐terminal fragments and small reductions in Aβ species, restoration to normal levels of Rab5 activity, reduced phosphorylated tau (p‐tau), and reversed deficits in TrkB (tropomyosin receptor kinase B) activation and in the Akt (protein kinase B [PKB]), ERK (extracellular signal‐regulated kinase), and CREB (cAMP response element–binding protein) signaling pathways. Remarkably, Posiphen treatment also restored the level of choline acetyltransferase protein to 2N levels. These findings support the APP gene dose hypothesis, point to the need for additional studies to explore the mechanisms by which increased APP gene expression acts to increase the risk for AD in DS, and to possible utility of treatments to normalize the levels of APP and its products for preventing AD in those with DS. Major challenges for the hypothesis Important unanswered questions are: (1) When should one intervene in those with DS; (2) would an APP‐based strategy have untoward consequences on possible adaptive changes induced by chronically increased APP gene dose; (3) do other genes present on chromosome 21, or on other chromosomes whose expression is dysregulated in DS, contribute to AD pathogenesis; and (4) can one model strategies that combine the use of an APP‐based treatment with those directed at other AD phenotypes including p‐tau and inflammation. Linkage to other major theories The APP gene dose hypothesis interfaces with the amyloid cascade hypothesis of AD as well as with the genetic and cell biological observations that support it. Moreover, upregulation of fl‐APP protein and products may drive downstream events that dysregulate tau homeostasis and inflammatory responses that contribute to propagation of AD pathogenesis.
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Affiliation(s)
- Xu-Qiao Chen
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Ahmad Salehi
- Department of Psychiatry & Behavioral Sciences, Stanford Medical School, Palo Alto, California, USA
| | - Matthew L Pearn
- Department of Anesthesiology, University of California San Diego, School of Medicine, La Jolla, California, USA.,V.A. San Diego Healthcare System, San Diego, California, USA
| | - Cassia Overk
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Phuong D Nguyen
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | | | | | - William C Mobley
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
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An In-Vitro Cell Model of Intracellular Protein Aggregation Provides Insights into RPE Stress Associated with Retinopathy. Int J Mol Sci 2020; 21:ijms21186647. [PMID: 32932802 PMCID: PMC7555953 DOI: 10.3390/ijms21186647] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/30/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022] Open
Abstract
Impaired cargo trafficking and the aggregation of intracellular macromolecules are key features of neurodegeneration, and a hallmark of aged as well as diseased retinal pigment epithelial (RPE) cells in the eye. Here, photoreceptor outer segments (POS), which are internalized daily by RPE cells, were modified by UV-irradiation to create oxidatively modified POS (OxPOS). Oxidative modification was quantified by a protein carbonyl content assay. Human ARPE-19 cells were synchronously pulsed with POS or OxPOS to study whether oxidatively modified cargos can recapitulate features of RPE pathology associated with blinding diseases. Confocal immunofluorescence microscopy analysis showed that OxPOS was trafficked to LAMP1, LAMP2 lysosomes and to LC3b autophagy vacuoles. Whilst POS were eventually degraded, OxPOS cargos were sequestered in late compartments. Co-localization of OxPOS was also associated with swollen autolysosomes. Ultrastructural analysis revealed the presence of electron-dense OxPOS aggregates in RPE cells, which appeared to be largely resistant to degradation. Measurement of cellular autofluorescence, using parameters used to assess fundus autofluorescence (FAF) in age-related macular disease (AMD) patients, revealed that OxPOS contributed significantly to a key feature of aged and diseased RPE. This in vitro cell model therefore represents a versatile tool to study disease pathways linked with RPE damage and sight-loss.
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54
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Argentati C, Tortorella I, Bazzucchi M, Emiliani C, Morena F, Martino S. The Other Side of Alzheimer's Disease: Influence of Metabolic Disorder Features for Novel Diagnostic Biomarkers. J Pers Med 2020; 10:E115. [PMID: 32899957 PMCID: PMC7563360 DOI: 10.3390/jpm10030115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 02/08/2023] Open
Abstract
Nowadays, the amyloid cascade hypothesis is the dominant model to explain Alzheimer's disease (AD) pathogenesis. By this hypothesis, the inherited genetic form of AD is discriminated from the sporadic form of AD (SAD) that accounts for 85-90% of total patients. The cause of SAD is still unclear, but several studies have shed light on the involvement of environmental factors and multiple susceptibility genes, such as Apolipoprotein E and other genetic risk factors, which are key mediators in different metabolic pathways (e.g., glucose metabolism, lipid metabolism, energetic metabolism, and inflammation). Furthermore, growing clinical evidence in AD patients highlighted the presence of affected systemic organs and blood similarly to the brain. Collectively, these findings revise the canonical understating of AD pathogenesis and suggest that AD has metabolic disorder features. This review will focus on AD as a metabolic disorder and highlight the contribution of this novel understanding on the identification of new biomarkers for improving an early AD diagnosis.
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Affiliation(s)
| | | | | | | | | | - Sabata Martino
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, 06123 Perugia, Italy; (C.A.); (I.T.); (M.B.); (C.E.); (F.M.)
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55
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The cellular machinery of post-endocytic APP trafficking in Alzheimer's disease: A future target for therapeutic intervention? PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 177:109-122. [PMID: 33453937 DOI: 10.1016/bs.pmbts.2020.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent data establish multiple defects in endocytic functions as early events initiating various neurodegenerative disorders, including Alzheimer's disease (AD). The genetic landscape resulting from genome-wide association studies (GWAS) reveals changes in post-endocytic trafficking of amyloid precursor protein (APP) in neurons leading to an increase in amyloidogenic processing, deficits in amyloid beta (Aβ) clearance, increases in intracellular Aβ, and other endosomal pathogenic phenotypes. Multiple genetic factors regulate each segment of endosomal and post-endosomal trafficking. Intriguingly, several studies indicate endosomal dysfunctions preceding Aβ pathology and tau phosphorylation. In this chapter we highlight the role of various GWAS-identified endosomal and post-endosomal gene products in initiating AD pathologies. We also summarize the functions of various genetic modifiers of post-endocytic trafficking of APP that may work as targets for therapeutic intervention in AD.
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56
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Wang Y, Wu Q, Anand BG, Karthivashan G, Phukan G, Yang J, Thinakaran G, Westaway D, Kar S. Significance of cytosolic cathepsin D in Alzheimer's disease pathology: Protective cellular effects of PLGA nanoparticles against β-amyloid-toxicity. Neuropathol Appl Neurobiol 2020; 46:686-706. [PMID: 32716575 DOI: 10.1111/nan.12647] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/25/2020] [Accepted: 07/12/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Evidence suggests that amyloid β (Aβ) peptides play an important role in the degeneration of neurons during the development of Alzheimer's disease (AD), the prevalent cause of dementia affecting the elderly. The endosomal-lysosomal system, which acts as a major site for Aβ metabolism, has been shown to exhibit abnormalities in vulnerable neurons of the AD brain, reflected by enhanced levels/expression of lysosomal enzymes including cathepsin D (CatD). At present, the implication of CatD in selective neuronal vulnerability in AD pathology remains unclear. METHODS We evaluated the role of CatD in the degeneration of neurons in Aβ-treated cultures, transgenic AD mouse model (that is 5xFAD) and post mortem AD brain samples. RESULTS Our results showed that Aβ1-42 -induced toxicity in cortical cultured neurons is associated with impaired lysosomal integrity, enhanced levels of carbonylated proteins and tau phosphorylation. The cellular and cytosolic levels/activity of CatD are also elevated in cultured neurons following exposure to Aβ peptide. Additionally, we observed that CatD cellular and subcellular levels/activity are increased in the affected cortex, but not in the unaffected cerebellum, of 5xFAD mice and post mortem AD brains. Interestingly, treatment of cultured neurons with nanoparticles PLGA, which targets lysosomal system, attenuated Aβ toxicity by reducing the levels of carbonylated proteins, tau phosphorylation and the level/distribution/activity of CatD. CONCLUSION Our study reveals that increased cytosolic level/activity of CatD play an important role in determining neuronal vulnerability in AD. Additionally, native PLGA can protect neurons against Aβ toxicity by restoring lysosomal membrane integrity, thus signifying its implication in attenuating AD.
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Affiliation(s)
- Y Wang
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - Q Wu
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - B G Anand
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - G Karthivashan
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - G Phukan
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - J Yang
- Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - G Thinakaran
- Department of Molecular Medicine, and Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, 33613, USA
| | - D Westaway
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada.,Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - S Kar
- Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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57
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Bécot A, Volgers C, van Niel G. Transmissible Endosomal Intoxication: A Balance between Exosomes and Lysosomes at the Basis of Intercellular Amyloid Propagation. Biomedicines 2020; 8:biomedicines8080272. [PMID: 32759666 PMCID: PMC7459801 DOI: 10.3390/biomedicines8080272] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 12/16/2022] Open
Abstract
In Alzheimer′s disease (AD), endolysosomal dysfunctions are amongst the earliest cellular features to appear. Each organelle of the endolysosomal system, from the multivesicular body (MVB) to the lysosome, contributes to the homeostasis of amyloid precursor protein (APP) cleavage products including β-amyloid (Aβ) peptides. Hence, this review will attempt to disentangle how changes in the endolysosomal system cumulate to the generation of toxic amyloid species and hamper their degradation. We highlight that the formation of MVBs and the generation of amyloid species are closely linked and describe how the molecular machineries acting at MVBs determine the generation and sorting of APP cleavage products towards their degradation or release in association with exosomes. In particular, we will focus on AD-related distortions of the endolysomal system that divert it from its degradative function to favour the release of exosomes and associated amyloid species. We propose here that such an imbalance transposed at the brain scale poses a novel concept of transmissible endosomal intoxication (TEI). This TEI would initiate a self-perpetuating transmission of endosomal dysfunction between cells that would support the propagation of amyloid species in neurodegenerative diseases.
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58
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Inflammation: major denominator of obesity, Type 2 diabetes and Alzheimer's disease-like pathology? Clin Sci (Lond) 2020; 134:547-570. [PMID: 32167154 DOI: 10.1042/cs20191313] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/27/2020] [Accepted: 02/28/2020] [Indexed: 02/08/2023]
Abstract
Adipose tissue is an active metabolic organ that contributes to processes such as energy storage and utilization and to the production of a number of metabolic agents, such as adipokines, which play a role in inflammation. In this review, we try to elucidate the connections between peripheral inflammation at obesity and Type 2 diabetes and the central inflammatory process. Multiple lines of evidence highlight the importance of peripheral inflammation and its link to neuroinflammation, which can lead to neurodegenerative diseases such as dementia, Alzheimer's disease (AD) and Parkinson's disease. In addition to the accumulation of misfolded amyloid beta (Aβ) peptide and the formation of the neurofibrillary tangles of hyperphosphorylated tau protein in the brain, activated microglia and reactive astrocytes are the main indicators of AD progression. They were found close to Aβ plaques in the brains of both AD patients and rodent models of Alzheimer's disease-like pathology. Cytokines are key players in pro- and anti-inflammatory processes and are also produced by microglia and astrocytes. The interplay of seemingly unrelated pathways between the periphery and the brain could, in fact, have a common denominator, with inflammation in general being a key factor affecting neuronal processes in the brain. An increased amount of white adipose tissue throughout the body seems to be an important player in pro-inflammatory processes. Nevertheless, other important factors should be studied to elucidate the pathological processes of and the relationship among obesity, Type 2 diabetes and neurodegenerative diseases.
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59
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Chae CW, Lee HJ, Choi GE, Jung YH, Kim JS, Lim JR, Kim SY, Hwang IK, Seong JK, Han HJ. High glucose-mediated PICALM and mTORC1 modulate processing of amyloid precursor protein via endosomal abnormalities. Br J Pharmacol 2020; 177:3828-3847. [PMID: 32436237 DOI: 10.1111/bph.15131] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 05/04/2020] [Accepted: 05/07/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Although diabetes mellitus (DM) is an important risk factor for Alzheimer's disease (AD), the detailed mechanism(s) by which DM regulates amyloid β (Aβ) processing is still unclear. The longer residence time of amyloid precursor protein (APP) in endosomes is critical for Aβ production and DM is known to cause endosomal dysregulation. Here we have examined the effects of high glucose on APP-producing endosomes and related signaling pathways. EXPERIMENTAL APPROACH To identify the underlying mechanisms, we investigated the effects of high glucose on abnormalities in early endosomes and related signalling pathways in human neuroblastoma cells. In vivo, diabetic mice treated with pharmacological inhibitors were used to examine endosomal dysfunction. KEY RESULTS The hippocampus of diabetic animals presented endosomal abnormalities and Aβ up-regulation. High glucose increased Aβ production through early endosomal enlargement achieved by increased lipid raft-mediated APP endocytosis. High glucose induced ROS-stimulated Sp1 activation, up-regulating phosphatidylinositol binding clathrin assembly protein (PICALM), clathrin heavy chain, and adaptor-related protein complex 2 alpha 1. PICALM facilitated clathrin-mediated APP endocytosis resulting in early endosomal enlargement. Meanwhile, AMPK/mTORC1-mediated autophagy defect and ROS- and mTORC1-mediated lysosomal dysfunction aggravated early endosomal enlargement under high glucose. Moreover, the increased Aβ production and cognitive deficits in diabetic mice were reversed by inhibition of early endosomal enlargement. CONCLUSION AND IMPLICATIONS High glucose induces early endosomal abnormalities through PICALM-induced APP endocytosis and mTORC1-inhibited endosomal clearance, up-regulating Aβ production. Thus, targeting PICALM and mTORC1 to prevent endosomal disorders is a promising strategy for managing diabetes-induced AD.
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Affiliation(s)
- Chang Woo Chae
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
| | - Hyun Jik Lee
- Laboratory of Veterinary Physiology, College of Veterinary Medicine, Chungbuk National University, Cheongju, South Korea.,Institute for Stem Cell and Regenerative Medicine (ISCRM), Chungbuk National University, Cheongju, South Korea
| | - Gee Euhn Choi
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
| | - Young Hyun Jung
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
| | - Jun Sung Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
| | - Jae Ryong Lim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
| | - Seo Yihl Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Je Kyung Seong
- BK21 PLUS Program for Creative Veterinary Science Research, and Research Institute for Veterinary Science, Seoul National University and Korea Mouse Phenotyping Center (KMPC), Seoul, South Korea
| | - Ho Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, Seoul National University, Seoul, South Korea
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Botté A, Lainé J, Xicota L, Heiligenstein X, Fontaine G, Kasri A, Rivals I, Goh P, Faklaris O, Cossec JC, Morel E, Rebillat AS, Nizetic D, Raposo G, Potier MC. Ultrastructural and dynamic studies of the endosomal compartment in Down syndrome. Acta Neuropathol Commun 2020; 8:89. [PMID: 32580751 PMCID: PMC7315513 DOI: 10.1186/s40478-020-00956-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/27/2020] [Indexed: 12/17/2022] Open
Abstract
Enlarged early endosomes have been visualized in Alzheimer's disease (AD) and Down syndrome (DS) using conventional confocal microscopy at a resolution corresponding to endosomal size (hundreds of nm). In order to overtake the diffraction limit, we used super-resolution structured illumination microscopy (SR-SIM) and transmission electron microscopies (TEM) to analyze the early endosomal compartment in DS.By immunofluorescence and confocal microscopy, we confirmed that the volume of Early Endosome Antigen 1 (EEA1)-positive puncta was 13-19% larger in fibroblasts and iPSC-derived neurons from individuals with DS, and in basal forebrain cholinergic neurons (BFCN) of the Ts65Dn mice modelling DS. However, EEA1-positive structures imaged by TEM or SR-SIM after chemical fixation had a normal size but appeared clustered. In order to disentangle these discrepancies, we imaged optimally preserved High Pressure Freezing (HPF)-vitrified DS fibroblasts by TEM and found that early endosomes were 75% denser but remained normal-sized.RNA sequencing of DS and euploid fibroblasts revealed a subgroup of differentially-expressed genes related to cargo sorting at multivesicular bodies (MVBs). We thus studied the dynamics of endocytosis, recycling and MVB-dependent degradation in DS fibroblasts. We found no change in endocytosis, increased recycling and delayed degradation, suggesting a "traffic jam" in the endosomal compartment.Finally, we show that the phosphoinositide PI (3) P, involved in early endosome fusion, is decreased in DS fibroblasts, unveiling a new mechanism for endosomal dysfunctions in DS and a target for pharmacotherapy.
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Affiliation(s)
- Alexandra Botté
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Jeanne Lainé
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
- Sorbonne Université, Département de Physiologie, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Laura Xicota
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Xavier Heiligenstein
- CryoCapCell, 155 Bd de l’hôpital, 75013 Paris, France
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, Paris, France
| | - Gaëlle Fontaine
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Amal Kasri
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Isabelle Rivals
- Equipe de Statistique Appliquée, ESPCI Paris, PSL Research University, UMRS 1158, Paris, France
| | - Pollyanna Goh
- The Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
| | - Orestis Faklaris
- ImagoSeine Imaging Core Facility, Institut Jacques Monod, CNRS UMR7592, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Jack-Christophe Cossec
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151 CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | | | - Dean Nizetic
- The Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Graça Raposo
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, Paris, France
| | - Marie-Claude Potier
- Paris Brain Institute (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
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The Sigma-2 Receptor/TMEM97, PGRMC1, and LDL Receptor Complex Are Responsible for the Cellular Uptake of Aβ42 and Its Protein Aggregates. Mol Neurobiol 2020; 57:3803-3813. [PMID: 32572762 DOI: 10.1007/s12035-020-01988-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/10/2020] [Indexed: 10/24/2022]
Abstract
Our lab has recently shown that the Sigma-2 Receptor/Transmembrane Protein 97 (TMEM97) and Progesterone Receptor Membrane Component 1 (PGRMC1) form a complex with the Low Density Lipoprotein Receptor (LDLR), and this intact complex is required for efficient uptake of lipoproteins such as LDL and apolipoprotein E (apoE). These receptors are expressed in the nervous system where they have implications in neurodegenerative diseases such as Alzheimer's disease (AD), where apoE is involved in neuronal uptake and accumulation of Aβ42, eventually cascading into neurodegeneration, synaptic dysfunction, and ultimately, dementia. We hypothesize that the intact Sigma-2 receptor complex-TMEM97, PGRMC1, and LDLR-is necessary for internalization of apoE and Aβ42 monomers (mAβ42) and oligomers (oAβ42), and the disruption of the receptor complex inhibits uptake. The results of this study suggest that the intact Sigma-2 receptor complex is a binding site for mAβ42 and oAβ42, in the presence or absence of apoE2, apoE3, and apoE4. The loss or pharmacological inhibition of one or both of these proteins results in the disruption of the complex leading to decreased uptake of mAβ42 and oAβ42 and apoE in primary neurons. The TMEM97, PGRMC1, and LDLR complex is a pathway for the cellular uptake of Aβ42 via apoE dependent and independent mechanisms. This study suggests that the complex may potentially be a novel pharmacological target to decrease neuronal Aβ42 internalization and accumulation, which may represent a new strategy for inhibiting the rate of neurotoxicity, neurodegeneration, and progression of AD.
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Shen R, Zhao X, He L, Ding Y, Xu W, Lin S, Fang S, Yang W, Sung K, Spencer B, Rissman RA, Lei M, Ding J, Wu C. Upregulation of RIN3 induces endosomal dysfunction in Alzheimer's disease. Transl Neurodegener 2020; 9:26. [PMID: 32552912 PMCID: PMC7301499 DOI: 10.1186/s40035-020-00206-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 06/01/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND In Alzheimer's Disease (AD), about one-third of the risk genes identified by GWAS encode proteins that function predominantly in the endocytic pathways. Among them, the Ras and Rab Interactor 3(RIN3) is a guanine nucleotide exchange factor (GEF) for the Rab5 small GTPase family and has been implicated to be a risk factor for both late onset AD (LOAD) and sporadic early onset AD (sEOAD). However, how RIN3 is linked to AD pathogenesis is currently undefined. METHODS Quantitative PCR and immunoblotting were used to measure the RIN3 expression level in mouse brain tissues and cultured basal forebrain cholinergic neuron (BFCNs). Immunostaining was used to define subcellular localization of RIN3 and to visualize endosomal changes in cultured primary BFCNs and PC12 cells. Recombinant flag-tagged RIN3 protein was purified from HEK293T cells and was used to define RIN3-interactomes by mass spectrometry. RIN3-interacting partners were validated by co-immunoprecipitation, immunofluorescence and yeast two hybrid assays. Live imaging of primary neurons was used to examine axonal transport of amyloid precursor protein (APP) and β-secretase 1 (BACE1). Immunoblotting was used to detect protein expression, processing of APP and phosphorylated forms of Tau. RESULTS We have shown that RIN3 mRNA level was significantly increased in the hippocampus and cortex of APP/PS1 mouse brain. Basal forebrain cholinergic neurons (BFCNs) cultured from E18 APP/PS1 mouse embryos also showed increased RIN3 expression accompanied by early endosome enlargement. In addition, via its proline rich domain, RIN3 recruited BIN1(bridging integrator 1) and CD2AP (CD2 associated protein), two other AD risk factors, to early endosomes. Interestingly, overexpression of RIN3 or CD2AP promoted APP cleavage to increase its carboxyl terminal fragments (CTFs) in PC12 cells. Upregulation of RIN3 or the neuronal isoform of BIN1 increased phosphorylated Tau level. Therefore, upregulation of RIN3 expression promoted accumulation of APP CTFs and increased phosphorylated Tau. These effects by RIN3 was rescued by the expression of a dominant negative Rab5 (Rab5S34N) construct. Our study has thus pointed to that RIN3 acts through Rab5 to impact endosomal trafficking and signaling. CONCLUSION RIN3 is significantly upregulated and correlated with endosomal dysfunction in APP/PS1 mouse. Through interacting with BIN1 and CD2AP, increased RIN3 expression alters axonal trafficking and procession of APP. Together with our previous studies, our current work has thus provided important insights into the role of RIN3 in regulating endosomal signaling and trafficking.
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Affiliation(s)
- Ruinan Shen
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Rd., Shanghai, 200025, China.,Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Xiaobei Zhao
- Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Lu He
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Rd., Shanghai, 200025, China
| | - Yongbo Ding
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China
| | - Wei Xu
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Rd., Shanghai, 200025, China.,Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Suzhen Lin
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Rd., Shanghai, 200025, China.,Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Savannah Fang
- Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Wanlin Yang
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Rd., Shanghai, 200025, China.,Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.,Department of Neurology, Zhuijiang Hospital, Southern Medical University, Guangzhou, China
| | - Kijung Sung
- Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Brian Spencer
- Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.,San Diego VA Health System, San Diego, CA, USA
| | - Ming Lei
- Shanghai Institute of Precision Medicine, Shanghai, 200125, China
| | - Jianqing Ding
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Rd., Shanghai, 200025, China.
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego School of Medicine, Room 312 MC-0624,9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
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Salvianolic Acid B improves cognitive impairment by inhibiting neuroinflammation and decreasing Aβ level in Porphyromonas gingivalis-infected mice. Aging (Albany NY) 2020; 12:10117-10128. [PMID: 32516126 PMCID: PMC7346047 DOI: 10.18632/aging.103306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/17/2020] [Indexed: 12/14/2022]
Abstract
Amyloid-β (Aβ) accumulation is one of the main pathological hallmarks of Alzheimer’s disease (AD). Porphyromonas gingivalis (P. gingivalis), the pathogen of chronic periodontitis, could cause Aβ accumulation and was identified in the brain of AD patients. Salvianolic Acid B (SalB) has been proven to have the neuroprotective effect. Whether SalB could protect against P. gingivalis-induced cognitive impairment is still unknown. In this study, a P. gingivalis-infected mouse model was employed to study the neuroprotective role of SalB. The results showed that SalB (20 and 40 mg/kg) treatment for 4 weeks could shorten the escape latency and improve the percentage of spontaneous alternation in the P. gingivalis-infected mice. SalB inhibited the levels of reactive oxygen species and malondialdehyde, while increased the levels of antioxidative enzymes (superoxide dismutase and glutathione peroxidase). SalB decreased the levels of IL-1β and IL-6, increased the mRNA levels of bdnf and ngf in the brain of P. gingivalis-infected mice. In addition, SalB obviously decreased the level of Aβ. SalB elevated the protein expression of ADAM10, while downregulated BACE1 and PS1. SalB increased the protein expression of LRP1, while decreased RAGE. In conclusion, SalB could improve cognitive impairment by inhibiting neuroinflammation and decreasing Aβ level in P. gingivalis-infected mice.
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Curtis ME, Yu D, Praticò D. Dysregulation of the Retromer Complex System in Down Syndrome. Ann Neurol 2020; 88:137-147. [PMID: 32320094 PMCID: PMC7384049 DOI: 10.1002/ana.25752] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 04/06/2020] [Accepted: 04/12/2020] [Indexed: 12/27/2022]
Abstract
Objective Most of the patients with Down syndrome (DS) develop Alzheimer's disease (AD) neuropathology by age 40. Although this increased susceptibility to AD in DS is thought to be primarily due to triplication of the amyloid precursor protein located on chromosome 21, the precise molecular mechanisms are not well understood. Recent evidence has implicated defective protein sorting and trafficking secondary to deficiencies in retromer complex proteins in AD pathogenesis. Thus, the objective of the present study is to assess the retromer complex system in DS. Methods Human postmortem brain tissue and fibroblasts from subjects with DS and healthy controls were examined for the various retromer protein components using Western blot analysis and reverse transcription quantitative polymerase chain reaction (RT‐qPCR). Results Retromer recognition core proteins were significantly decreased in DS fibroblasts, and in both the hippocampi and cortices of young (age 15–40 years old) and aged (40–65 years old) subjects with DS compared with controls. Correlation analyses showed a significant inverse relationship between recognition core proteins and levels of soluble forms of Aβ 1–40 and 1–42 in both hippocampus (n = 33, Spearman = −0.59 to −0.38, p ≤ 0.03 for VPS35, VPS26, VPS29, and VPS26B) and cortex tissue (n = 57, Spearman = −0.46 to −0.27, p ≤ 0.04 for VPS35, VPS26, and VPS29) of the same patients. Interpretation We conclude that dysregulation of the retromer complex system is an early event in the development of the AD‐like pathology and cognitive decline in DS, and for this reason the system could represent a novel potential therapeutic target for DS. ANN NEUROL 2020 ANN NEUROL 2020;88:137–147
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Affiliation(s)
- Mary Elizabeth Curtis
- Alzheimer's Center at Temple, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Daohai Yu
- Department of Clinical Sciences, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Domenico Praticò
- Alzheimer's Center at Temple, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
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Ahmadpour D, Babazadeh R, Nystrom T. Hitchhiking on vesicles: a way to harness age-related proteopathies? FEBS J 2020; 287:5068-5079. [PMID: 32336030 DOI: 10.1111/febs.15345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/06/2020] [Accepted: 04/23/2020] [Indexed: 12/27/2022]
Abstract
Central to proteopathies and leading to most age-related neurodegenerative disorders is a failure in protein quality control (PQC). To harness the toxicity of misfolded and damaged disease proteins, such proteins are either refolded, degraded by temporal PQC, or sequestered by spatial PQC into specific, organelle-associated, compartments within the cell. Here, we discuss the impact of vesicle trafficking pathways in general, and syntaxin 5 in particular, as key players in spatial PQC directing misfolded proteins to the surface of vacuole and mitochondria, which facilitates their clearance and detoxification. Since boosting vesicle trafficking genetically can positively impact on spatial PQC and make cells less sensitive to misfolded disease proteins, we speculate that regulators of such trafficking might serve as therapeutic targets for age-related neurological disorders.
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Affiliation(s)
- Doryaneh Ahmadpour
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Sweden.,Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, Sahlgrenska Academy at the University of Gothenburg, Sweden
| | - Roja Babazadeh
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Sweden.,Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Thomas Nystrom
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health-AgeCap, University of Gothenburg, Sweden
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Yang M, Wang Y, Liang G, Xu Z, Chu CT, Wei H. Alzheimer's Disease Presenilin-1 Mutation Sensitizes Neurons to Impaired Autophagy Flux and Propofol Neurotoxicity: Role of Calcium Dysregulation. J Alzheimers Dis 2020; 67:137-147. [PMID: 30636740 DOI: 10.3233/jad-180858] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Disruption of intracellular Ca2+ homeostasis and associated autophagy dysfunction contribute to neuropathology in Alzheimer's disease (AD). OBJECTIVE To study the effects of propofol on cell viability via its effects on intracellular Ca2+ homeostasis, and the impact of autophagy, in a neuronal model of presenilin-mutated familial AD (FAD). METHODS We treated PC12 cells, stably transfected with either mutated presenilin-1 (L286V) or wild type (WT) controls, with propofol at different doses and durations, in the presence or absence of extracellular Ca2+, antagonists of inositol trisphosphate receptors (InsP3R, xestospongin C) and/or ryanodine receptors (RYR, dantrolene), or an inhibitor of autophagy flux (Bafilomycin). We determined cell viability, cytosolic Ca2+ concentrations ([Ca2+]c), vATPase protein expression, and lysosomal acidification. RESULTS The propofol dose- and time-dependently decreased cell viability significantly more in L286V than WT cells, especially at the pharmacological dose (>50μM), and together with bafilomycin (40 nM). Clinically used concentrations of propofol (<20μM) tended to increase cell viability. Propofol significantly increased [Ca2+]c more in L286V than in WT cells, which was associated with decrease of vATPase expression and localization to the lysosome. Both toxicity and increased Ca2+ levels were ameliorated by inhibiting InsP3R/RYR. However, the combined inhibition of both receptors paradoxically increased [Ca2+]c, by inducing Ca2+ influx from the extracellular space, causing greater cytotoxicity. CONCLUSION Impairment in autophagy function acts to deteriorate cell death induced by propofol in FAD neuronal cells. Cell death is ameliorated by either RYR or InsP3R antagonists on their own, but not when both are co-administered.
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Affiliation(s)
- Meirong Yang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Yan Wang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Ge Liang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhendong Xu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Anesthesiology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Charleen T Chu
- Department of Pathology, Division of Neuropathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Huafeng Wei
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Arbo B, Cechinel L, Palazzo R, Siqueira I. Endosomal dysfunction impacts extracellular vesicle release: Central role in Aβ pathology. Ageing Res Rev 2020; 58:101006. [PMID: 31891813 DOI: 10.1016/j.arr.2019.101006] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 01/04/2023]
Abstract
Alzheimer's Disease (AD) is characterized by progressive loss of cognitive abilities; senile plaques represent the major histopathological findings. Amyloid precursor protein (APP) processing machinery, and its product amyloid-beta (Aβ) peptide, have been found in extracellular vesicles (EVs), specifically exosomes, which allows for Aβ peptide aggregation and subsequent senile plaques deposition. We review the APP processing imbalance in EVs, autophagic and endosomal pathways in AD. Increased intraluminal vesicle (ILV) production and exosome release appear to counteract the endosomal dysfunction of APP processing; however, this process results in elevated amyloidogenic processing of APP and augmented senile plaque deposition. Several players related to APP processing and dysfunctional endosomal-lysosomal-exosomal (and other EVs) pathway are described, and the interconnected systems are discussed. The components Arc, p75, Rab11 and retromer complex emerge as candidates for key convergent mechanisms that lead to increased EVs loaded with APP machinery and Aβ levels, in atrophy and damage of basal forebrain cholinergic neurons in AD.
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68
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Drosophila as a model to understand autophagy deregulation in human disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020. [PMID: 32620249 DOI: 10.1016/bs.pmbts.2020.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Autophagy has important functions in normal physiology to maintain homeostasis and protect against cellular stresses by the removal of harmful cargos such as dysfunctional organelles, protein aggregates and invading pathogens. The deregulation of autophagy is a hallmark of many diseases and therapeutic targeting of autophagy is highly topical. With the complex role of autophagy in disease it is essential to understand the genetic and molecular basis of the contribution of autophagy to pathogenesis. The model organism, Drosophila, provides a genetically amenable system to dissect out the contribution of autophagy to human disease models. Here we review the roles of autophagy in human disease and how autophagy studies in Drosophila have contributed to the understanding of pathophysiology.
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69
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Afghah Z, Chen X, Geiger JD. Role of endolysosomes and inter-organellar signaling in brain disease. Neurobiol Dis 2020; 134:104670. [PMID: 31707116 PMCID: PMC7184921 DOI: 10.1016/j.nbd.2019.104670] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/14/2019] [Accepted: 11/05/2019] [Indexed: 12/29/2022] Open
Abstract
Endosomes and lysosomes (endolysosomes) are membrane bounded organelles that play a key role in cell survival and cell death. These acidic intracellular organelles are the principal sites for intracellular hydrolytic activity required for the maintenance of cellular homeostasis. Endolysosomes are involved in the degradation of plasma membrane components, extracellular macromolecules as well as intracellular macromolecules and cellular fragments. Understanding the physiological significance and pathological relevance of endolysosomes is now complicated by relatively recent findings of physical and functional interactions between endolysosomes with other intracellular organelles including endoplasmic reticulum, mitochondria, plasma membranes, and peroxisomes. Indeed, evidence clearly indicates that endolysosome dysfunction and inter-organellar signaling occurs in different neurodegenerative diseases including Alzheimer's disease (AD), HIV-1 associated neurocognitive disease (HAND), Parkinson's disease (PD) as well as various forms of brain cancer such as glioblastoma multiforme (GBM). These findings open new areas of cell biology research focusing on understanding the physiological actions and pathophysiological consequences of inter-organellar communication. Here, we will review findings of others and us that endolysosome de-acidification and dysfunction coupled with impaired inter-organellar signaling is involved in the pathogenesis of AD, HAND, PD, and GBM. A more comprehensive appreciation of cell biology and inter-organellar signaling could lead to the development of new drugs to prevent or cure these diseases.
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Affiliation(s)
- Zahra Afghah
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201, United States of America
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201, United States of America
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201, United States of America.
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70
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Autophagy modulates Aβ accumulation and formation of aggregates in yeast. Mol Cell Neurosci 2020; 104:103466. [PMID: 31962153 DOI: 10.1016/j.mcn.2020.103466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/03/2020] [Accepted: 01/06/2020] [Indexed: 11/20/2022] Open
Abstract
Intracellular accumulation of amyloid-β protein (Aβ) is an early event in Alzheimer's disease (AD). The autophagy-lysosomal pathway is an important pathway for maintaining cellular proteostasis and for the removal of damaged organelles and protein aggregates in all eukaryotes. Despite mounting evidence showing that modulating autophagy promotes clearance of Aβ aggregates, the regulatory mechanisms and signalling pathways underlying this process remain poorly understood. In order to gain better insight we used our previously characterised yeast model expressing GFP-Aβ42 to identify genes that regulate the removal of Aβ42 aggregates by autophagy. We report that GFP-Aβ42 is sequestered and is selectively transported to vacuole for degradation and that autophagy is the prominent pathway for clearance of aggregates. Next, to identify genes that selectively promote the removal of Aβ42 aggregates, we screened levels of GFP-Aβ42 and non-aggregating GFP-Aβ42 (19:34) proteins in a panel of 192 autophagy mutants lacking genes involved in regulation and initiation of the pathway, cargo selection and degradation processes. The nutrient and stress signalling genes RRD1, SNF4, GCN4 and SSE1 were identified. Deletion of these genes impaired GFP-Aβ42 clearance and their overexpression reduced GFP-Aβ42 levels in yeast. Overall, our findings identify a novel role for these nutrient and stress signalling genes in the targeted elimination of Aβ42 aggregates, which offer a promising avenue for developing autophagy based therapies to suppress amyloid deposition in AD.
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71
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Gomez W, Morales R, Maracaja-Coutinho V, Parra V, Nassif M. Down syndrome and Alzheimer's disease: common molecular traits beyond the amyloid precursor protein. Aging (Albany NY) 2020; 12:1011-1033. [PMID: 31918411 PMCID: PMC6977673 DOI: 10.18632/aging.102677] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/25/2019] [Indexed: 02/07/2023]
Abstract
Alzheimer’s disease (AD) is the most prevalent type of dementia. Down syndrome (DS) is the leading genetic risk factor for Early-Onset AD, prematurely presenting the classic pathological features of the brain with AD. Augmented gene dosage, including the APP gene, could partially cause this predisposition. Recent works have revealed that alterations in chromosome location due to the extra Chromosome 21, as well as epigenetic modifications, could promote changes in gene expression other than those from Chromosome 21. As a result, similar pathological features and cellular dysfunctions in DS and AD, including impaired autophagy, lysosomal activity, and mitochondrial dysfunction, could be controlled beyond APP overexpression. In this review, we highlight some recent data regarding the origin of the shared features between DS and AD and explore the mechanisms concerning cognitive deficiencies in DS associated with dementia, which could shed some light into the search for new therapeutic targets for AD treatment.
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Affiliation(s)
- Wileidy Gomez
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile.,Departamento de Bioquímica y Biología Molecular and Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Rodrigo Morales
- Department of Neurology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.,CIBQA, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Vinicius Maracaja-Coutinho
- Departamento de Bioquímica y Biología Molecular and Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.,Centro de Modelamiento Molecular, Biofísica y Bioinformática (CM2B2), Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Valentina Parra
- Departamento de Bioquímica y Biología Molecular and Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile.,Center for Exercise, Metabolism, and Cancer Studies (CEMC), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Autophagy Research Center, Universidad de Chile, Santiago, Chile
| | - Melissa Nassif
- Laboratory of Neuroprotection and Autophagy, Center for Integrative Biology, Faculty of Science, Universidad Mayor, Santiago, Chile.,Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
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Tam JM, Josephson L, Pilozzi AR, Huang X. A Novel Dual Fluorochrome Near-Infrared Imaging Probe for Potential Alzheimer's Enzyme Biomarkers-BACE1 and Cathepsin D. Molecules 2020; 25:E274. [PMID: 31936569 PMCID: PMC7024167 DOI: 10.3390/molecules25020274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 11/16/2022] Open
Abstract
A molecular imaging probe to fluorescently image the β-site of the amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) and cathepsin D (CatD) enzymes associated with Alzheimer's disease (AD) was designed and synthesized. This imaging probe was built upon iron oxide nanoparticles (cross-linked dextran iron oxide nanoparticles, or CLIO). Peptide substrates containing a terminal near-infrared fluorochrome (fluorophore emitting at 775 nm for CatD or fluorophore emitting at 669 nm for BACE1) were conjugated to the CLIO nanoparticles. The CatD substrate contained a phenylalanine-phenylalanine cleavage site more specific to CatD than BACE1. The BACE1 substrate contained the sequence surrounding the leucine-asparagine cleavage site of the BACE1 found in the Swedish mutation of APP, which is more specific to BACE1 than CatD. These fluorescently-labeled peptide substrates were then conjugated to the nanoparticle. The nanoparticle probes were purified by gel filtration, and their fluorescence intensities were determined using a fluorescence plate reader. The CatD peptide substrate demonstrated a 15.5-fold increase in fluorescence when incubated with purified CatD enzyme, and the BACE1 substrate exhibited a 31.5-fold increase in fluorescence when incubated with purified BACE1 enzyme. Probe specificity was also demonstrated in the human H4 neuroglioma cells and the H4 cells stably transfected with BACE1 in which the probe monitored enzymatic cleavage. In the H4 and H4-BACE1 cells, BACE1 and active CatD activity increased, an occurrence that was reflected in enzyme expression levels as determined by immunoblotting. These results demonstrate the applicability of this probe for detecting potential Alzheimer's enzyme biomarkers.
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Affiliation(s)
- Jenny M. Tam
- Wyss Institute and Harvard Medical School, Boston, MA 02115, USA;
| | - Lee Josephson
- Center for Molecular Imaging Research (CMIR), Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA;
| | - Alexander R. Pilozzi
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA;
| | - Xudong Huang
- Neurochemistry Laboratory, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA;
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73
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Balasubramaniam M, Parcon PA, Bose C, Liu L, Jones RA, Farlow MR, Mrak RE, Barger SW, Griffin WST. Interleukin-1β drives NEDD8 nuclear-to-cytoplasmic translocation, fostering parkin activation via NEDD8 binding to the P-ubiquitin activating site. J Neuroinflammation 2019; 16:275. [PMID: 31882005 PMCID: PMC6935243 DOI: 10.1186/s12974-019-1669-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 12/02/2019] [Indexed: 01/14/2023] Open
Abstract
Background Neuroinflammation, typified by elevated levels of interleukin-1 (IL-1) α and β, and deficits in proteostasis, characterized by accumulation of polyubiquitinated proteins and other aggregates, are associated with neurodegenerative disease independently and through interactions of the two phenomena. We investigated the influence of IL-1β on ubiquitination via its impact on activation of the E3 ligase parkin by either phosphorylated ubiquitin (P-Ub) or NEDD8. Methods Immunohistochemistry and Proximity Ligation Assay were used to assess colocalization of parkin with P-tau or NEDD8 in hippocampus from Alzheimer patients (AD) and controls. IL-1β effects on PINK1, P-Ub, parkin, P-parkin, and GSK3β—as well as phosphorylation of parkin by GSK3β—were assessed in cell cultures by western immunoblot, using two inhibitors and siRNA knockdown to suppress GSK3β. Computer modeling characterized the binding and the effects of P-Ub and NEDD8 on parkin. IL-1α, IL-1β, and parkin gene expression was assessed by RT-PCR in brains of 2- and 17-month-old PD-APP mice and wild-type littermates. Results IL-1α, IL-1β, and parkin mRNA levels were higher in PD-APP mice compared with wild-type littermates, and IL-1α-laden glia surrounded parkin- and P-tau-laden neurons in human AD. Such neurons showed a nuclear-to-cytoplasmic translocation of NEDD8 that was mimicked in IL-1β-treated primary neuronal cultures. These cultures also showed higher parkin levels and GSK3β-induced parkin phosphorylation; PINK1 levels were suppressed. In silico simulation predicted that binding of either P-Ub or NEDD8 at a singular position on parkin opens the UBL domain, exposing Ser65 for parkin activation. Conclusions The promotion of parkin- and NEDD8-mediated ubiquitination by IL-1β is consistent with an acute neuroprotective role. However, accumulations of P-tau and P-Ub and other elements of proteostasis, such as translocated NEDD8, in AD and in response to IL-1β suggest either over-stimulation or a proteostatic failure that may result from chronic IL-1β elevation, easily envisioned considering its early induction in Down’s syndrome and mild cognitive impairment. The findings further link autophagy and neuroinflammation, two important aspects of AD pathogenesis, which have previously been only loosely related.
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Affiliation(s)
| | - Paul A Parcon
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.,Department of Psychiatry, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Chhanda Bose
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Ling Liu
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Richard A Jones
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.,Geriatric Research Education and Clinical Center at the Central Arkansas Healthcare Veterans System, Little Rock, AR, 72205, USA
| | - Martin R Farlow
- Department of Neurology, Indiana Alzheimer Disease Center, Indiana University, Bloomington, USA
| | - Robert E Mrak
- Department of Pathology, University of Toledo Health Sciences Campus, Toledo, OH, 43614, USA
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.,Geriatric Research Education and Clinical Center at the Central Arkansas Healthcare Veterans System, Little Rock, AR, 72205, USA
| | - W Sue T Griffin
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA. .,Geriatric Research Education and Clinical Center at the Central Arkansas Healthcare Veterans System, Little Rock, AR, 72205, USA.
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74
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Mathews PM, Levy E. Exosome Production Is Key to Neuronal Endosomal Pathway Integrity in Neurodegenerative Diseases. Front Neurosci 2019; 13:1347. [PMID: 31911768 PMCID: PMC6920185 DOI: 10.3389/fnins.2019.01347] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/29/2019] [Indexed: 12/28/2022] Open
Abstract
Dysfunction of the endosomal–lysosomal system is a prominent pathogenic factor in Alzheimer’s disease (AD) and other neurodevelopmental and neurodegenerative disorders. We and others have extensively characterized the neuronal endosomal pathway pathology that results from either triplication of the amyloid-β precursor protein (APP) gene in Down syndrome (DS) or from expression of the apolipoprotein E ε4 allele (APOE4), the greatest genetic risk factor for late-onset AD. More recently brain exosomes, extracellular vesicles that are generated within and released from endosomal compartments, have been shown to be altered in DS and by APOE4 expression. In this review, we discuss the emerging data arguing for an interdependence between exosome production and endosomal pathway integrity in the brain. In vitro and in vivo studies indicate that altered trafficking through the endosomal pathway or compromised cargo turnover within lysosomes can affect the production, secretion, and content of exosomes. Conversely, exosome biogenesis can affect the endosomal–lysosomal system. Indeed, we propose that efficient exosome release helps to modulate flux through the neuronal endosomal pathway by decompressing potential “traffic jams.” Exosome secretion may have the added benefit of unburdening the neuron’s lysosomal system by delivering endosomal–lysosomal material into the extracellular space, where other cell types may contribute to the degradation of neuronal debris. Thus, maintaining robust neuronal exosome production may prevent or mitigate endosomal and lysosomal abnormalities linked to aging and neurodegenerative diseases. While the current evidence suggests that the exosomal system in the brain can be modulated both by membrane lipid composition and the expression of key proteins that contribute to the formation and secretion of exosomes, how exosomal pathway-regulatory elements sense and respond to perturbations in the endosomal pathway is not well understood. Based upon findings from the extensively studied DS and APOE4 models, we propose that enhanced neuronal exosome secretion can be a protective response, reducing pathological disruption of the endosomal–lysosomal system in disease-vulnerable neurons. Developing therapeutic approaches that help to maintain or enhance neuronal exosome biogenesis and release may be beneficial in a range of disorders of the central nervous system.
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Affiliation(s)
- Paul M Mathews
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, United States.,Department of Psychiatry, New York University Langone Health, New York, NY, United States.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, United States
| | - Efrat Levy
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, United States.,Department of Psychiatry, New York University Langone Health, New York, NY, United States.,NYU Neuroscience Institute, New York University Langone Health, New York, NY, United States.,Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, NY, United States
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75
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Williams ME, Zulu SS, Stein DJ, Joska JA, Naudé PJW. Signatures of HIV-1 subtype B and C Tat proteins and their effects in the neuropathogenesis of HIV-associated neurocognitive impairments. Neurobiol Dis 2019; 136:104701. [PMID: 31837421 DOI: 10.1016/j.nbd.2019.104701] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/18/2019] [Accepted: 12/08/2019] [Indexed: 11/16/2022] Open
Abstract
HIV-associated neurocognitive impairments (HANI) are a spectrum of neurological disorders due to the effects of HIV-1 on the central nervous system (CNS). The HIV-1 subtypes; HIV-1 subtype B (HIV-1B) and HIV-1 subtype C (HIV-1C) are responsible for the highest prevalence of HANI and HIV infections respectively. The HIV transactivator of transcription (Tat) protein is a major contributor to the neuropathogenesis of HIV. The effects of the Tat protein on cells of the CNS is determined by the subtype-associated amino acid sequence variations. The extent to which the sequence variation between Tat-subtypes contribute to underlying mechanisms and neurological outcomes are not clear. In this review of the literature, we discuss how amino acid variations between HIV-1B Tat (TatB) and HIV-1C Tat (TatC) proteins contribute to the potential underlying neurobiological mechanisms of HANI. Tat-C is considered to be a more effective transactivator, whereas Tat-B may exert increased neurovirulence, including neuronal apoptosis, monocyte infiltration into the brain, (neuro)inflammation, oxidative stress and blood-brain barrier damage. These findings support the premise that Tat variants from different HIV-1 subtypes may direct neurovirulence and neurological outcomes in HANI.
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Affiliation(s)
- Monray E Williams
- Department of Psychiatry and Mental Health and Neuroscience Institute, Brain Behaviour Unit, University of Cape Town, Cape Town, South Africa.
| | - Simo S Zulu
- Department of Psychiatry and Mental Health and Neuroscience Institute, Brain Behaviour Unit, University of Cape Town, Cape Town, South Africa
| | - Dan J Stein
- Department of Psychiatry and Mental Health and Neuroscience Institute, Brain Behaviour Unit, University of Cape Town, Cape Town, South Africa; SAMRC Unit on Risk and Resilience in Mental Disorders and Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - John A Joska
- Division of Neuropsychiatry, Department of Psychiatry and Mental Health, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Petrus J W Naudé
- Department of Psychiatry and Mental Health and Neuroscience Institute, Brain Behaviour Unit, University of Cape Town, Cape Town, South Africa
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76
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Cannavo C, Tosh J, Fisher EMC, Wiseman FK. Using mouse models to understand Alzheimer's disease mechanisms in the context of trisomy of chromosome 21. PROGRESS IN BRAIN RESEARCH 2019; 251:181-208. [PMID: 32057307 DOI: 10.1016/bs.pbr.2019.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
People who have Down syndrome are at significantly elevated risk of developing early onset Alzheimer's disease that causes dementia (AD-DS). Here we review recent progress in modeling the development of AD-DS in mouse models. These studies provide insight into mechanisms underlying Alzheimer's disease and generate new clinical research questions. In addition, they suggest potential new targets for disease prevention therapies.
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Affiliation(s)
- Claudia Cannavo
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; UK Dementia Research Institute at University College, London, United Kingdom
| | - Justin Tosh
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom
| | - Elizabeth M C Fisher
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; The London Down Syndrome Consortium (LonDownS), London, United Kingdom
| | - Frances K Wiseman
- Department of Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom; The London Down Syndrome Consortium (LonDownS), London, United Kingdom; UK Dementia Research Institute at University College, London, United Kingdom.
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77
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Llorente P, Kristen H, Sastre I, Toledano-Zaragoza A, Aldudo J, Recuero M, Bullido MJ. A Free Radical-Generating System Regulates Amyloid Oligomers: Involvement of Cathepsin B. J Alzheimers Dis 2019; 66:1397-1408. [PMID: 30400084 DOI: 10.3233/jad-170159] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Amyloid-β (Aβ), a major component of senile plaques, is generated via the proteolysis of amyloid-β protein precursor (AβPP). This cleavage also produces AβPP fragment-derived oligomers which can be highly neurotoxic. AβPP metabolism/processing is affected by many factors, one of which is oxidative stress (OS). Associated with aging, OS is an important risk factor for Alzheimer's disease. In addition, the protein degradation systems, especially those involving cathepsins, are impaired in aging brains. Moreover, cathepsin B (CTSB) is a cysteine protease with potentially specific roles in AβPP proteolysis (β-secretase activity) and Aβ clearance (Aβ degradative activity). The present work examines the effect of OS and the involvement of CTSB in amyloid oligomer formation. The xanthine/xanthine oxidase (X-XOD) free radical generating system induced the partial inhibition of CTSB activity, which was accompanied by an increase in large amyloid oligomers. These were located throughout the cytosol and in endo-lysosomal vesicles. Cells treated with the CTSB inhibitor CA-074Me also showed increased amyloid oligomer levels, whereas those subjected to OS in the presence of the inhibitor showed no such increase. However, CTSB inhibition clearly modulated the AβPP metabolism/processing induced by X-XOD, as revealed by the increase in intracellular AβPP and secreted α-secretase-cleaved soluble AβPP. The present results suggest that CTSB participates in the changes of amyloid oligomer induced by mild OS.
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Affiliation(s)
- Patricia Llorente
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Henrike Kristen
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Isabel Sastre
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto de Investigacion Sanitaria "Hospital la Paz" (IdIPaz), Madrid, Spain
| | - Ana Toledano-Zaragoza
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Jesús Aldudo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto de Investigacion Sanitaria "Hospital la Paz" (IdIPaz), Madrid, Spain
| | - María Recuero
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto de Investigacion Sanitaria "Hospital la Paz" (IdIPaz), Madrid, Spain
| | - María J Bullido
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto de Investigacion Sanitaria "Hospital la Paz" (IdIPaz), Madrid, Spain
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78
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Botté A, Potier MC. Focusing on cellular biomarkers: The endo-lysosomal pathway in Down syndrome. PROGRESS IN BRAIN RESEARCH 2019; 251:209-243. [PMID: 32057308 DOI: 10.1016/bs.pbr.2019.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Down syndrome (DS) is the most frequent chromosomal disorder. It is caused by the triplication of human chromosome 21, leading to increased dosage of a variety of genes including APP (Amyloid Precursor Protein). Mainly for this reason, individuals with DS are at high risk to develop Alzheimer's disease (AD). Extensive literature identified various morphological and molecular abnormalities in the endo-lysosomal pathway both in DS and AD. Most studies in this field investigated the causative role of APP (Amyloid Precursor Protein) in endo-lysosomal dysfunctions, thus linking phenotypes observed in DS and AD. In DS context, several lines of evidence and emerging hypotheses suggest that other molecular players and pathways may be implicated in these complex phenotypes. In this review, we outline the normal functioning of endosomal trafficking and summarize the research on endo-lysosomal dysfunction in DS in light of AD findings. We emphasize the role of genes of chromosome 21 implicated in endocytosis to explain endosomal abnormalities and set the limitations and perspectives of models used to explore endo-lysosomal dysfunction in DS and find new biomarkers. The review highlights the complexity of endo-lysosomal dysfunction in DS and suggests directions for future research in the field.
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Affiliation(s)
- Alexandra Botté
- Institut du Cerveau et de la Moelle épinière (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Marie-Claude Potier
- Institut du Cerveau et de la Moelle épinière (ICM), CNRS UMR7225, INSERM U1127, Sorbonne Université, Hôpital de la Pitié-Salpêtrière, Paris, France.
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79
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Essayan-Perez S, Zhou B, Nabet AM, Wernig M, Huang YWA. Modeling Alzheimer's disease with human iPS cells: advancements, lessons, and applications. Neurobiol Dis 2019; 130:104503. [PMID: 31202913 PMCID: PMC6689423 DOI: 10.1016/j.nbd.2019.104503] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/24/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022] Open
Abstract
One in three people will develop Alzheimer's disease (AD) or another dementia and, despite intense research efforts, treatment options remain inadequate. Understanding the mechanisms of AD pathogenesis remains our principal hurdle to developing effective therapeutics to tackle this looming medical crisis. In light of recent discoveries from whole-genome sequencing and technical advances in humanized models, studying disease risk genes with induced human neural cells presents unprecedented advantages. Here, we first review the current knowledge of the proposed mechanisms underlying AD and focus on modern genetic insights to inform future studies. To highlight the utility of human pluripotent stem cell-based innovations, we then present an update on efforts in recapitulating the pathophysiology by induced neuronal, non-neuronal and a collection of brain cell types, departing from the neuron-centric convention. Lastly, we examine the translational potentials of such approaches, and provide our perspectives on the promise they offer to deepen our understanding of AD pathogenesis and to accelerate the development of intervention strategies for patients and risk carriers.
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Affiliation(s)
- Sofia Essayan-Perez
- Department of Molecular and Cellular Physiology, Stanford University Medical School, Stanford, CA 94305, United States of America
| | - Bo Zhou
- Department of Molecular and Cellular Physiology, Stanford University Medical School, Stanford, CA 94305, United States of America; Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University Medical School, Stanford, CA 94305, United States of America
| | - Amber M Nabet
- Department of Molecular and Cellular Physiology, Stanford University Medical School, Stanford, CA 94305, United States of America
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University Medical School, Stanford, CA 94305, United States of America
| | - Yu-Wen Alvin Huang
- Department of Molecular and Cellular Physiology, Stanford University Medical School, Stanford, CA 94305, United States of America.
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80
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Ubina T, Magallanes M, Srivastava S, Warden CD, Yee JK, Salvaterra PM. A Human Embryonic Stem Cell Model of Aβ-Dependent Chronic Progressive Neurodegeneration. Front Neurosci 2019; 13:1007. [PMID: 31616241 PMCID: PMC6763609 DOI: 10.3389/fnins.2019.01007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/05/2019] [Indexed: 11/13/2022] Open
Abstract
We describe the construction and phenotypic analysis of a human embryonic stem cell model of progressive Aβ-dependent neurodegeneration (ND) with potential relevance to Alzheimer’s disease (AD). We modified one allele of the normal APP locus to directly express a secretory form of Aβ40 or Aβ42, enabling expression from this edited allele to bypass the normal amyloidogenic APP processing pathway. Following neuronal differentiation, edited cell lines specifically accumulate intracellular aggregated/oligomeric Aβ, exhibit a synaptic deficit, and have an abnormal accumulation of endolysosomal vesicles. Edited cultures progress to a stage of overt ND. All phenotypes appear at earlier culture times for Aβ42 relative to Aβ40. Whole transcriptome RNA-Seq analysis identified 23 up and 70 down regulated genes (differentially expressed genes) with similar directional fold change but larger absolute values in the Aβ42 samples suggesting common underlying pathogenic mechanisms. Pathway/annotation analysis suggested that down regulation of extracellular matrix and cilia functions is significantly overrepresented. This cellular model could be useful for uncovering mechanisms directly linking Aβ to neuronal death and as a tool to screen for new therapeutic agents that slow or prevent human ND.
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Affiliation(s)
- Teresa Ubina
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States.,Department of Biology, California State University, San Bernardino, San Bernardino, CA, United States
| | - Martha Magallanes
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Saumya Srivastava
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Charles D Warden
- Integrative Genomics Core, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Jiing-Kuan Yee
- Department of Diabetes, Beckman Research Institute - City of Hope, Duarte, CA, United States.,Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Paul M Salvaterra
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States.,Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute - City of Hope, Duarte, CA, United States
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81
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Khan N, Haughey NJ, Nath A, Geiger JD. Involvement of organelles and inter-organellar signaling in the pathogenesis of HIV-1 associated neurocognitive disorder and Alzheimer's disease. Brain Res 2019; 1722:146389. [PMID: 31425679 DOI: 10.1016/j.brainres.2019.146389] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/26/2019] [Accepted: 08/13/2019] [Indexed: 12/30/2022]
Abstract
Endolysosomes, mitochondria, peroxisomes, endoplasmic reticulum, and plasma membranes are now known to physically and functionally interact with each other. Such findings of inter-organellar signaling and communication has led to a resurgent interest in cell biology and an increased appreciation for the physiological actions and pathological consequences of the dynamic physical and chemical communications occurring between intracellular organelles. Others and we have shown that HIV-1 proteins implicated in the pathogenesis of neuroHIV and that Alzheimer's disease both affects the structure and function of intracellular organelles. Intracellular organelles are highly mobile, and their intracellular distribution almost certainly affects their ability to interact with other organelles and to regulate such important physiological functions as endolysosome acidification, cell motility, and nutrient homeostasis. Indeed, compounds that acidify endolysosomes cause endolysosomes to exhibit a mainly perinuclear pattern while compounds that de-acidify endolysosomes cause these organelles to exhibit a larger profile as well as movement towards plasma membranes. Endolysosome pH might be an early event in the pathogenesis of neuroHIV and Alzheimer's disease and in terms of organellar biology endolysosome changes might be upstream of HIV-1 protein-induced changes to other organelles. Thus, inter-organellar signaling mechanisms might be involved in the pathogenesis of neuroHIV and other neurological disorders, and a better understanding of inter-organellar signaling might lead to improved therapeutic strategies.
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Affiliation(s)
- Nabab Khan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, United States
| | - Norman J Haughey
- Department of Neurology, Johns Hopkins University, Baltimore, MD, United States
| | - Avindra Nath
- National Institute of Neurological Diseases and Stroke, Bethesda, MD, United States
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, United States.
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82
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Hamlett ED, LaRosa A, Mufson EJ, Fortea J, Ledreux A, Granholm AC. Exosome release and cargo in Down syndrome. Dev Neurobiol 2019; 79:639-655. [PMID: 31347291 DOI: 10.1002/dneu.22712] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/20/2019] [Accepted: 07/22/2019] [Indexed: 12/11/2022]
Abstract
Down syndrome (DS) is a multisystem disorder affecting 1 in 800 births worldwide. Advancing technology, medical treatment, and social intervention have dramatically increased life expectancy, yet there are many etiologies of this disorder that are in need of further research. The advent of the ability to capture extracellular vesicles (EVs) in blood from specific cell types allows for the investigation of novel intracellular processes. Exosomes are one type of EVs that have demonstrated great potential in uncovering new biomarkers of neurodegeneration and disease, and also that appear to be intricately involved in the transsynaptic spread of pathogenic factors underlying Alzheimer's disease and other neurological diseases. Exosomes are nanosized vesicles, generated in endosomal multivesicular bodies (MVBs) and secreted by most cells in the body. Since exosomes are important mediators of intercellular communication and genetic exchange, they have emerged as a major research focus and have revealed novel biological sequelae involved in conditions afflicting the DS population. This review summarizes current knowledge on exosome biology in individuals with DS, both early in life and in aging individuals. Collectively these studies have demonstrated that complex multicellular processes underlying DS etiologies may include abnormal formation and secretion of extracellular vesicles such as exosomes.
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Affiliation(s)
- Eric D Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Angela LaRosa
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina
| | - Elliott J Mufson
- Department of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | - Juan Fortea
- Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, CIBERNED, Universitat Autònoma de Barcelona, Barcelona, Spain.,Alzheimer's Disease and Other Cognitive Disorders Unit, Department of Neurology, Hospital Clínic, Institut d'Investigació Biomèdica August Pi i Sunyer, University of Barcelona, Barcelona, Spain
| | - Aurélie Ledreux
- Department of Biological Sciences and the Knoebel Institute for Healthy Aging, University of Denver, Denver, Colorado
| | - Ann-Charlotte Granholm
- Department of Biological Sciences and the Knoebel Institute for Healthy Aging, University of Denver, Denver, Colorado
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83
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Pérez-González R, Gauthier SA, Sharma A, Miller C, Pawlik M, Kaur G, Kim Y, Levy E. A pleiotropic role for exosomes loaded with the amyloid β precursor protein carboxyl-terminal fragments in the brain of Down syndrome patients. Neurobiol Aging 2019; 84:26-32. [PMID: 31479861 DOI: 10.1016/j.neurobiolaging.2019.07.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/25/2019] [Accepted: 07/26/2019] [Indexed: 01/08/2023]
Abstract
Down syndrome (DS) is characterized by cognitive deficits throughout the life span and with the development of aging-dependent Alzheimer's type neuropathology, which is related to the triplication of the amyloid β precursor protein (APP) gene. A dysfunctional endosomal system in neurons is an early characteristic of DS and APP metabolites accumulate in endosomes in DS neurons. We have previously shown enhanced release of exosomes in the brain of DS patients and the mouse model of DS Ts[Rb(12.1716)]2Cje (Ts2), and by DS fibroblasts, as compared with diploid controls. Here, we demonstrate that exosome-enriched extracellular vesicles (hereafter called EVs) isolated from DS and Ts2 brains, and from the culture media of human DS fibroblasts are enriched in APP carboxyl-terminal fragments (APP-CTFs) as compared with diploid controls. Moreover, APP-CTFs levels increase in an age-dependent manner in EVs isolated from the brain of Ts2 mice. The release of APP-CTFs-enriched exosomes may have a pathogenic role by transporting APP-CTFs into naïve neurons and propagating these neurotoxic metabolites, which are also a source of amyloid β, throughout the brain, but also provides a benefit to DS neurons by shedding APP-CTFs accumulated intracellularly.
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Affiliation(s)
- Rocío Pérez-González
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Health, New York, NY, USA.
| | - Sébastien A Gauthier
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Ajay Sharma
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Chelsea Miller
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Monika Pawlik
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Gurjinder Kaur
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Yohan Kim
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Health, New York, NY, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Health, New York, NY, USA; Department of Biochemistry & Molecular Pharmacology, NYU Langone Health, New York, NY, USA; Neuroscience Institute, NYU Langone Health, New York, NY, USA
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84
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Keeling E, Chatelet DS, Johnston DA, Page A, Tumbarello DA, Lotery AJ, Ratnayaka JA. Oxidative Stress and Dysfunctional Intracellular Traffic Linked to an Unhealthy Diet Results in Impaired Cargo Transport in the Retinal Pigment Epithelium (RPE). Mol Nutr Food Res 2019; 63:e1800951. [PMID: 30835933 DOI: 10.1002/mnfr.201800951] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/18/2019] [Indexed: 12/19/2022]
Abstract
SCOPE Oxidative stress and dysregulated intracellular trafficking are associated with an unhealthy diet which underlies pathology. Here, these effects on photoreceptor outer segment (POS) trafficking in the retinal pigment epithelium (RPE), a major pathway of disease underlying irreversible sight-loss, are studied. METHODS AND RESULTS POS trafficking is studied in ARPE-19 cells using an algorithm-based quantification of confocal-immunofluorescence data supported by ultrastructural studies. It is shown that although POS are tightly regulated and trafficked via Rab5, Rab7 vesicles, LAMP1/2 lysosomes and LC3b-autophagosomes, there is also a considerable degree of variation and flexibility in this process. Treatment with H2 O2 and bafilomycin A1 reveals that oxidative stress and dysregulated autophagy target intracellular compartments and trafficking in strikingly different ways. These effects appear limited to POS-containing vesicles, suggesting a cargo-specific effect. CONCLUSION The findings offer insights into how RPE cells cope with stress, and how mechanisms influencing POS transport/degradation can have different outcomes in the senescent retina. These shed new light on cellular processes underlying retinopathies such as age-related macular degeneration. The discoveries reveal how diet and nutrition can cause fundamental alterations at a cellular level, thus contributing to a better understanding of the diet-disease axis.
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Affiliation(s)
- Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
| | - David S Chatelet
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Johnston
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - Anton Page
- Biomedical Imaging Unit, University of Southampton, MP12, Tremona Road, SO16 6YD, UK
| | - David A Tumbarello
- Biological Sciences, Faculty of Natural & Environmental Sciences, University of Southampton, Life Sciences Building 85, SO17 1BJ, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, MP806, Tremona Road, SO16 6YD, UK
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85
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Restoring synaptic function through multimodal therapeutics. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 168:257-275. [PMID: 31699320 DOI: 10.1016/bs.pmbts.2019.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Alzheimer's disease (AD) is the major form of dementia and a growing epidemic for which no disease-modifying treatments exist. AD is characterized by the early loss of synapses in the brain and, at later stages, neuronal death accompanied with progressive loss of cognitive functions. Here we focus on the mechanisms involved in the maintenance of the synapse and how their perturbation leads to synaptic loss. We suggest treatment strategies that particularly target energy metabolism in terms of cholesterol and glucose biochemistry in neurons and astrocytes We also discuss the potential of restoring impaired protein homeostasis through autophagy. These pathways are analyzed from a basic science perspective and suggest new avenues for discovery. We also propose several targets for both basic and translational therapeutics in these pathways and provide perspective on future AD treatment.
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86
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Hui L, Ye Y, Soliman ML, Lakpa KL, Miller NM, Afghah Z, Geiger JD, Chen X. Antiretroviral Drugs Promote Amyloidogenesis by De-Acidifying Endolysosomes. J Neuroimmune Pharmacol 2019; 16:159-168. [PMID: 31338753 DOI: 10.1007/s11481-019-09862-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/30/2019] [Indexed: 12/15/2022]
Abstract
Antiretroviral therapeutics (ART) have effectively increased the long-term survival of HIV-1 infected individuals. However, the prevalence of HIV-1 associated neurocognitive disorders (HAND) has increased and so too have clinical manifestations and pathological features of Alzheimer's disease (AD) in people living with HIV-1/AIDS. Although underlying mechanisms are not clear, chronic exposure to ART drugs has been implicated in the development of AD-like symptoms and pathology. ART drugs are categorized according to their mechanism of action in controlling HIV-1 levels. All ART drugs are organic compounds that can be classified as being either weak acids or weak bases, and these physicochemical properties may be of central importance to ART drug-induced AD-like pathology because weak bases accumulate in endolysosomes, weak bases can de-acidify endolysosomes where amyloidogenesis occurs, and endolysosome de-acidification increases amyloid beta (Aβ) protein production and decreases Aβ degradation. Here, we investigated the effects of ART drugs on endolysosome pH and Aβ levels in rat primary cultured neurons. ART drugs that de-acidified endolysosomes increased Aβ levels, whereas those that acidified endolysosomes decreased Aβ levels. Acidification of endolysosomes with the mucolipin transient receptor potential (TRPML) channel agonist ML-SA1 blocked ART drug-induced increases in Aβ levels. Further, ART drug-induced endolysosome de-acidification increased endolysosome sizes; effects that were blocked by ML-SA1-induced endolysosome acidification. These results suggest that ART drug-induced endolysosome de-acidification plays an important role in ART drug-induced amyloidogenesis and that endolysosome acidification might attenuate AD-like pathology in HIV-1 positive people taking ART drugs that de-acidify endolysosomes. Graphical Abstract.
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Affiliation(s)
- Liang Hui
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Yan Ye
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Mahmoud L Soliman
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Koffi L Lakpa
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Nicole M Miller
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Zahra Afghah
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Jonathan D Geiger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA
| | - Xuesong Chen
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 504 Hamline Street, Grand Forks, ND, 58203, USA.
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87
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Chen XQ, Mobley WC. Alzheimer Disease Pathogenesis: Insights From Molecular and Cellular Biology Studies of Oligomeric Aβ and Tau Species. Front Neurosci 2019; 13:659. [PMID: 31293377 PMCID: PMC6598402 DOI: 10.3389/fnins.2019.00659] [Citation(s) in RCA: 176] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/07/2019] [Indexed: 01/08/2023] Open
Abstract
Alzheimer disease (AD) represents an oncoming epidemic that without an effective treatment promises to exact extraordinary human and financial burdens. Studies of pathogenesis are essential for defining targets for discovering disease-modifying treatments. Past studies of AD neuropathology provided valuable, albeit limited, insights. Nevertheless, building on these findings, recent studies have provided an increasingly rich harvest of genetic, molecular and cellular data that are creating unprecedented opportunities to both understand and treat AD. Among the most significant are those documenting the presence within the AD brain of toxic oligomeric species of Aβ and tau. Existing data support the view that such species can propagate and spread within neural circuits. To place these findings in context we first review the genetics and neuropathology of AD, including AD in Down syndrome (AD-DS). We detail studies that support the existence of toxic oligomeric species while noting the significant unanswered questions concerning their precise structures, the means by which they spread and undergo amplification and how they induce neuronal dysfunction and degeneration. We conclude by offering a speculative synthesis for how oligomers of Aβ and tau initiate and drive pathogenesis. While 100 years after Alzheimer's first report there is much still to learn about pathogenesis and the discovery of disease-modifying treatments, the application of new concepts and sophisticated new tools are poised to deliver important advances for combatting AD.
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Affiliation(s)
- Xu-Qiao Chen
- Department of Neurosciences, University of California, San Diego, San Diego, CA, United States
| | - William C. Mobley
- Department of Neurosciences, University of California, San Diego, San Diego, CA, United States
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88
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Maity BK, Das AK, Dey S, Moorthi UK, Kaur A, Dey A, Surendran D, Pandit R, Kallianpur M, Chandra B, Chandrakesan M, Arumugam S, Maiti S. Ordered and Disordered Segments of Amyloid-β Drive Sequential Steps of the Toxic Pathway. ACS Chem Neurosci 2019; 10:2498-2509. [PMID: 30763064 DOI: 10.1021/acschemneuro.9b00015] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
While the roles of intrinsically disordered protein domains in driving interprotein interactions are increasingly well-appreciated, the mechanism of toxicity of disease-causing disordered proteins remains poorly understood. A prime example is Alzheimer's disease (AD) associated amyloid beta (Aβ). Aβ oligomers are highly toxic partially structured peptide assemblies with a distinct ordered region (residues ∼10-40) and a shorter disordered region (residues ∼1-9). Here, we investigate the role of this disordered domain and its relation to the ordered domain in the manifestation of toxicity through a set of Aβ fragments and stereoisomers designed for this purpose. We measure their effects on lipid membranes and cultured neurons, probing their toxicity, intracellular distributions, and specific molecular interactions using the techniques of confocal imaging, lattice light sheet imaging, fluorescence lifetime imaging, and fluorescence correlation spectroscopy. Remarkably, we find that neither part-Aβ10-40 or Aβ1-9, is toxic by itself. The ordered part (Aβ10-40) is the major determinant of how Aβ attaches to lipid bilayers, enters neuronal cells, and localizes primarily in the late endosomal compartments. However, once Aβ enters the cell, it is the disordered part (only when it is connected to the rest of the peptide) that has a strong and stereospecific interaction with an unknown cellular component, as demonstrated by distinct changes in the fluorescence lifetime of a fluorophore attached to the N-terminal. This interaction appears to commit Aβ to the toxic pathway. Our findings correlate well with Aβ sites of familial AD mutations, a significant fraction of which cluster in the disordered region. We conclude that, while the ordered region dictates attachment and cellular entry, the key to toxicity lies in the ordered part presenting the disordered part for a specific cellular interaction.
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Affiliation(s)
- Barun Kumar Maity
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Anand Kant Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Simli Dey
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | | | | | - Arpan Dey
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Dayana Surendran
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Rucha Pandit
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Mamata Kallianpur
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Bappaditya Chandra
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Muralidharan Chandrakesan
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | | | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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89
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Type II Diabetes Mellitus Accelerates Age-Dependent Aβ Pathology in Cynomolgus Monkey Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1128:133-145. [PMID: 31062328 DOI: 10.1007/978-981-13-3540-2_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Accumulating evidence suggests that diabetes mellitus (DM) is one of the strongest risk factors for developing Alzheimer's disease (AD). However, it remains unclear how DM accelerates AD pathology in the brain. Cynomolgus monkey (Macaca fascicularis) is one of the nonhuman primates used for biomedical research, and we can observe spontaneous formation of AD pathology, such as senile plaques (SPs) and neurofibrillary tangles (NFTs), with the advance of aging. Furthermore, obesity is occasionally observed and frequently leads to development of type II DM (T2DM) in laboratory-housed cynomolgus monkeys. These findings suggest that cynomolgus monkey is a useful species to study the relationship between T2DM and AD pathology. In T2DM-affected monkey brains, SPs were observed in frontal and temporal lobe cortices almost 5 years earlier than healthy control monkeys. Moreover, age-related endocytic pathology, such as intraneuronal accumulation of enlarged endosomes, was exacerbated in T2DM-affected monkey brains. Since accumulating evidences suggest that endocytic dysfunction is involved in Aβ pathology, T2DM may aggravate age-related endocytic dysfunction, leading to the acceleration of Aβ pathology.
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90
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Downregulation of SNX27 expression does not exacerbate amyloidogenesis in the APP/PS1 Alzheimer's disease mouse model. Neurobiol Aging 2019; 77:144-153. [DOI: 10.1016/j.neurobiolaging.2019.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/01/2019] [Accepted: 01/13/2019] [Indexed: 12/20/2022]
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91
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Abstract
Effective therapeutic strategy against Alzheimer's disease (AD) requires early detection of AD; however, clinical diagnosis of Alzheimer's disease (AD) is not precise and a definitive diagnosis of AD is only possible via postmortem examination for AD pathological hallmarks including senile plaques composed of Aβ and neuro fibrillary tangles composed of phosphorylated tau. Although a variety of biomarker has been developed and used in clinical setting, none of them robustly predicts subsequent clinical course of AD. Thus, it is essential to identify new biomarkers that may facilitate the diagnosis of early stages of AD, prediction of subsequent clinical course, and development of new therapeutic strategies. Given that pathological hallmarks of AD including Aβaccumulation and the presence of phosphorylated tau are also detected in peripheral tissues, AD is considered a systemic disease. Without the protection of blood-brain barrier, systemic factors can affect peripheral tissues much earlier than neurons in brain. Here, we will discuss the development of AD-like pathology in skeletal muscle and the potential use of skeletal muscle biopsy (examination for Aβaccumulation and phosphorylated tau) as a biomarker for AD.
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Affiliation(s)
- X Chen
- Department of Biomedical Sciences, University of North Dakota, USA
| | - N M Miller
- Department of Biomedical Sciences, University of North Dakota, USA
| | - Z Afghah
- Department of Biomedical Sciences, University of North Dakota, USA
| | - J D Geiger
- Department of Biomedical Sciences, University of North Dakota, USA
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92
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Cao J, Zhong MB, Toro CA, Zhang L, Cai D. Endo-lysosomal pathway and ubiquitin-proteasome system dysfunction in Alzheimer's disease pathogenesis. Neurosci Lett 2019; 703:68-78. [PMID: 30890471 DOI: 10.1016/j.neulet.2019.03.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/19/2019] [Accepted: 03/11/2019] [Indexed: 01/04/2023]
Abstract
Several lines of evidence have shown that defects in the endo-lysosomal autophagy degradation pathway and the ubiquitin-proteasome system play a role in Alzheimer's Disease (AD) pathogenesis and pathophysiology. Early pathological changes, such as marked enlargement of endosomal compartments, gradual accumulation of autophagic vacuoles (AVs) and lysosome dyshomeostasis, are well-recognized in AD. In addition to these pathological indicators, many genetic variants of key regulators in the endo-lysosomal autophagy networks and the ubiquitin-proteasome system have been found to be associated with AD. Furthermore, altered expression levels of key proteins in these pathways have been found in AD human brain tissues, primary cells and AD mouse models. In this review, we discuss potential disease mechanisms underlying the dysregulation of protein homeostasis governing systems. While the importance of two major protein degradation pathways in AD pathogenesis has been highlighted, targeted therapy at key components of these pathways has great potential in developing novel therapeutic interventions for AD. Future investigations are needed to define molecular mechanisms by which these complex regulatory systems become malfunctional at specific stages of AD development and progression, which will facilitate future development of novel therapeutic interventions. It is also critical to investigate all key components of the protein degradation pathways, both upstream and downstream, to improve our abilities to manipulate transport pathways with higher efficacy and less side effects.
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Affiliation(s)
- Jiqing Cao
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; The Central Hospital of The Hua Zhong University of Science and Technology, Wuhan, China.
| | - Margaret B Zhong
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Barnard College of Columbia University, New York, NY 10027, United States.
| | - Carlos A Toro
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; National Center for the Medical Consequences of Spinal Cord Injury, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Larry Zhang
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Dongming Cai
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Neurology Section, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; The Central Hospital of The Hua Zhong University of Science and Technology, Wuhan, China.
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93
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Koh JY, Kim HN, Hwang JJ, Kim YH, Park SE. Lysosomal dysfunction in proteinopathic neurodegenerative disorders: possible therapeutic roles of cAMP and zinc. Mol Brain 2019; 12:18. [PMID: 30866990 PMCID: PMC6417073 DOI: 10.1186/s13041-019-0439-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/04/2019] [Indexed: 12/22/2022] Open
Abstract
A number of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, share intra- and/or extracellular deposition of protein aggregates as a common core pathology. While the species of accumulating proteins are distinct in each disease, an increasing body of evidence indicates that defects in the protein clearance system play a crucial role in the gradual accumulation of protein aggregates. Among protein degradation systems, the endosome-autophagosome-lysosome pathway (EALP) is the main degradation machinery, especially for large protein aggregates. Lysosomal dysfunction or defects in fusion with vesicles containing cargo are commonly observed abnormalities in proteinopathic neurodegenerative diseases. In this review, we discuss the available evidence for a mechanistic connection between components of the EALP-especially lysosomes-and neurodegenerative diseases. We also focus on lysosomal pH regulation and its significance in maintaining flux through the EALP. Finally, we suggest that raising cAMP and free zinc levels in brain cells may be beneficial in normalizing lysosomal pH and EALP flux.
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Affiliation(s)
- Jae-Young Koh
- Department of Neurology, University of Ulsan College of Medicine, Seoul, South Korea.
| | - Ha Na Kim
- Neural Injury Lab, Biomedical Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
| | - Jung Jin Hwang
- Department of Convergence Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea
| | - Yang-Hee Kim
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Sang Eun Park
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, South Korea
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94
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Pacheco-Quinto J, Clausen D, Pérez-González R, Peng H, Meszaros A, Eckman CB, Levy E, Eckman EA. Intracellular metalloprotease activity controls intraneuronal Aβ aggregation and limits secretion of Aβ via exosomes. FASEB J 2019; 33:3758-3771. [PMID: 30481490 PMCID: PMC6404562 DOI: 10.1096/fj.201801319r] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/29/2018] [Indexed: 01/09/2023]
Abstract
Accumulating evidence suggests that the abnormal aggregation of amyloid-β (Αβ) peptide in Alzheimer's disease (AD) begins intraneuronally, within vesicles of the endosomal-lysosomal pathway where Aβ is both generated and degraded. Metalloproteases, including endothelin-converting enzyme (ECE)-1 and -2, reside within these vesicles and normally limit the accumulation of intraneuronally produced Aβ. In this study, we determined whether disruption of Aβ catabolism could trigger Aβ aggregation within neurons and increase the amount of Aβ associated with exosomes, small extracellular vesicles derived from endosomal multivesicular bodies. Using cultured cell lines, primary neurons, and organotypic brain slices from an AD mouse model, we found that pharmacological inhibition of the ECE family of metalloproteases increased intracellular and extracellular Aβ levels and promoted the intracellular formation of Aβ oligomers, a process that did not require internalization of secreted Aβ. In vivo, the accumulation of intraneuronal Aβ aggregates was accompanied by increased levels of both extracellular and exosome-associated Aβ, including oligomeric species. Neuronal exosomes were found to contain both ECE-1 and -2 activities, suggesting that multivesicular bodies are intracellular sites of Aβ degradation by these enzymes. ECE dysfunction could lead to the accumulation of intraneuronal Aβ aggregates and their subsequent release into the extracellular space via exosomes.-Pacheco-Quinto, J., Clausen, D., Pérez-González, R., Peng, H., Meszaros, A., Eckman, C. B., Levy, E., Eckman, E. A. Intracellular metalloprotease activity controls intraneuronal Aβ aggregation and limits secretion of Aβ via exosomes.
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Affiliation(s)
- Javier Pacheco-Quinto
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
- Atlantic Health System, Morristown, New Jersey, USA
| | - Dana Clausen
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
| | - Rocío Pérez-González
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, USA
- Department of Psychiatry, NYU Langone Medical Center, New York, New York, USA
| | - Hui Peng
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
| | - Austin Meszaros
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
| | | | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, USA
- Department of Psychiatry, NYU Langone Medical Center, New York, New York, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, New York, USA; and
- Neuroscience Institute, NYU Langone Medical Center, New York, New York, USA
| | - Elizabeth A. Eckman
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey, USA
- Atlantic Health System, Morristown, New Jersey, USA
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95
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Thellung S, Corsaro A, Nizzari M, Barbieri F, Florio T. Autophagy Activator Drugs: A New Opportunity in Neuroprotection from Misfolded Protein Toxicity. Int J Mol Sci 2019; 20:ijms20040901. [PMID: 30791416 PMCID: PMC6412775 DOI: 10.3390/ijms20040901] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 02/11/2019] [Accepted: 02/14/2019] [Indexed: 02/06/2023] Open
Abstract
The aim of this review is to critically analyze promises and limitations of pharmacological inducers of autophagy against protein misfolding-associated neurodegeneration. Effective therapies against neurodegenerative disorders can be developed by regulating the “self-defense” equipment of neurons, such as autophagy. Through the degradation and recycling of the intracellular content, autophagy promotes neuron survival in conditions of trophic factor deprivation, oxidative stress, mitochondrial and lysosomal damage, or accumulation of misfolded proteins. Autophagy involves the activation of self-digestive pathways, which is different for dynamics (macro, micro and chaperone-mediated autophagy), or degraded material (mitophagy, lysophagy, aggrephagy). All neurodegenerative disorders share common pathogenic mechanisms, including the impairment of autophagic flux, which causes the inability to remove the neurotoxic oligomers of misfolded proteins. Pharmacological activation of autophagy is typically achieved by blocking the kinase activity of mammalian target of rapamycin (mTOR) enzymatic complex 1 (mTORC1), removing its autophagy suppressor activity observed under physiological conditions; acting in this way, rapamycin provided the first proof of principle that pharmacological autophagy enhancement can induce neuroprotection through the facilitation of oligomers’ clearance. The demand for effective disease-modifying strategies against neurodegenerative disorders is currently stimulating the development of a wide number of novel molecules, as well as the re-evaluation of old drugs for their pro-autophagic potential.
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Affiliation(s)
- Stefano Thellung
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Alessandro Corsaro
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Mario Nizzari
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Federica Barbieri
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
| | - Tullio Florio
- Sezione di Farmacologia, Dipartimento di Medicina Interna & Centro di Eccellenza per la Ricerca Biomedica (CEBR), Università di Genova, 16132 Genova, Italy.
- IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy.
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Strickland MR, Holtzman DM. Dr. Jekyll and Mr. Hyde: ApoE explains opposing effects of neuronal LRP1. J Clin Invest 2019; 129:969-971. [PMID: 30741722 DOI: 10.1172/jci127578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia, and its pathogenesis is initiated by the accumulation of amyloid-β (Aβ) into extracellular plaques. Apolipoprotein E4 (ApoE4) is the largest genetic risk factor for sporadic AD and contributes to AD pathogenesis by influencing clearance and seeding of the initial aggregation of Aβ. In this issue of the JCI, Tachibana et al. investigated the relationship between neuronal LRP1 expression and ApoE4-mediated seeding of Aβ and showed that knockout of neuronal LRP1 prevents the increase in Aβ pathology caused by ApoE4 expression. These findings give insight into potential therapeutic targets for the preclinical phase of AD and the pathogenesis of Aβ pathology.
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97
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Huang L, Lin M, Zhong X, Yang H, Deng M. Galangin decreases p‑tau, Aβ42 and β‑secretase levels, and suppresses autophagy in okadaic acid‑induced PC12 cells via an Akt/GSK3β/mTOR signaling‑dependent mechanism. Mol Med Rep 2019; 19:1767-1774. [PMID: 30628698 DOI: 10.3892/mmr.2019.9824] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 10/19/2018] [Indexed: 11/05/2022] Open
Abstract
Okadaic acid (OA)‑induced neurotoxicity may be considered a novel tool used to study Alzheimer's disease (AD) pathology, and may be helpful in the development of a novel therapeutic approach. It has been reported that galangin inhibits β‑site amyloid precursor protein‑cleaving enzyme 1 expression, which is a key enzyme for amyloid β (Aβ) generation and is a potential drug candidate for AD therapy. However, further studies are required to confirm its neuroprotective effects in other AD models. The present study aimed to explore the neuroprotective effects of galangin on OA‑induced neurotoxicity in PC12 cells. The cells were divided into the following groups: Control group, model group (175 nM OA for 48 h) and galangin groups (0.25, 0.5 and 1 µg/ml). Beclin‑1, phosphorylated (p)‑protein kinase B (Akt), p‑glycogen synthase kinase (GSK)3β and p‑mechanistic target of rapamycin (mTOR) expression was also measured in the following PC12 cell groups: Control group, model group, 3‑methyladenine group (5 nM), rapamycin group (100 nM) and galangin group (1 µg/ml). The levels of β‑secretase, Aβ42 and p‑tau were detected by ELISA, Beclin‑1 expression was examined by immunohistochemistry and the protein expression levels of p‑Akt, p‑mTOR p‑GSK3β, and Beclin‑1 were detected by western blotting. Galangin treatment enhanced cell viability in cells treated with OA, and decreased β‑secretase, Aβ42 and p‑tau levels. In addition, it suppressed Beclin‑1 and p‑GSK3β expression, but promoted p‑Akt and p‑mTOR expression by regulating the Akt/GSK3β/mTOR pathway. These results indicated that galangin protected PC12 cells from OA‑induced cytotoxicity and inhibited autophagy via the Akt/GSK3β/mTOR pathway, thus suggesting that it may be considered a potential therapeutic agent for AD.
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Affiliation(s)
- Liping Huang
- School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang, Guangdong 524048, P.R. China
| | - Mingqin Lin
- College of Pharmacy, Hainan Medical University, Haikou, Hainan 571199, P.R. China
| | - Xiaoqin Zhong
- Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510120, P.R. China
| | - Hongyan Yang
- College of Pharmacy, Hainan Medical University, Haikou, Hainan 571199, P.R. China
| | - Minzhen Deng
- Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510120, P.R. China
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98
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Nie J, Jiang LS, Zhang Y, Tian Y, Li LS, Lu YL, Yang WJ, Shi JS. Dendrobium nobile Lindl. Alkaloids Decreases the Level of Intracellular β-Amyloid by Improving Impaired Autolysosomal Proteolysis in APP/PS1 Mice. Front Pharmacol 2018; 9:1479. [PMID: 30618767 PMCID: PMC6305391 DOI: 10.3389/fphar.2018.01479] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022] Open
Abstract
As the major degradation pathway for long-lived proteins and organelles, macroautophagy is a decisive factor for the survival and longevity of cells. The existing evidence indicates that the disruption of substrate proteolysis in autolysosomes is the main mechanism underlying autophagy failure in Alzheimer’s disease (AD). Thus, the restoration of normal lysosomal proteolysis and autophagy efficiency is a novel therapeutic strategy in the treatment of AD. In this study, 9-month-old APPswe/PS1ΔE9 transgenic (APP/PS1) mice were administered Dendrobium nobile Lindl. alkaloids (DNLA, 40 and 80 mg/kg) or Metformin (80 mg/kg), and age-matched wild-type mice were administered an isovolumic vehicle orally once a day for 4 months. The results demonstrated that DNLA significantly improved learning and memory function in APP/PS1 transgenic mice in the Morris water maze. Furthermore, DNLA could increase the expression of the v-ATPase A1 subunit to facilitate lysosomal acidification, prompt the dissociation of the cation independent-mannose-phosphate receptor from cathepsin (cat) D, promote the proteolytic maturation of cat D, increase the degradation of accumulated autophagic vacuoles (AVs) and β-amyloid (Aβ) contained in the AVs, and alleviate neuronal and synaptic injury. These findings demonstrate that DNLA improves learning and memory function in APP/PS1 mice, and the mechanisms appear to be due to the promotion of intracellular Aβ degradation by increasing the protein level of v-ATPase A1 and then improving autolysosomal acidification and proteolysis.
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Affiliation(s)
- Jing Nie
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Lin-Shan Jiang
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yu Zhang
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yong Tian
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Li-Sheng Li
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Yan-Liu Lu
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Wen-Jin Yang
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
| | - Jing-Shan Shi
- Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China
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99
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Kageyama Y, Saito A, Pletnikova O, Rudow GL, Irie Y, An Y, Murakami K, Irie K, Resnick SM, Fowler DR, Martin LJ, Troncoso JC. Amyloid β toxic conformer has dynamic localization in the human inferior parietal cortex in absence of amyloid plaques. Sci Rep 2018; 8:16895. [PMID: 30442978 PMCID: PMC6237870 DOI: 10.1038/s41598-018-35004-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/18/2018] [Indexed: 01/15/2023] Open
Abstract
Amyloid β (Aβ) plays a critical role in the pathogenesis of Alzheimer's disease. Nevertheless, its distribution and clearance before Aβ plaque formation needs to be elucidated. Using an optimized immunofluorescent staining method, we examined the distribution of Aβ in the post-mortem parietal cortex of 35 subjects, 30 to 65 years of age, APOE ε3/ε3, without AD lesions. We used 11A1, an antibody against an Aβ conformer which forms neurotoxic oligomers. 11A1 immunoreactivity (IR) was present in cortical neurons, pericapillary spaces, astrocytes and the extracellular compartment at 30 years of age. The percentage of neurons with 11A1 IR did not change with age, but the number and percentage of astrocytes with 11A1 IR gradually increased. Notably, the percentage of pericapillary spaces labeled with 11A1 IR declined significantly in the 5th decade of the life, at the same time that 11A1 IR increased in the extracellular space. Our findings indicate that the Aβ toxic conformer is normally present in various cell types and brain parenchyma, and appears to be constitutively produced, degraded, and cleared from the inferior parietal cortex. The decrease in pericapillary Aβ and the concomitant increase of extracellular Aβ may reflect an age-associated impairment in Aβ clearance from the brain.
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Affiliation(s)
- Yusuke Kageyama
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan
| | - Atsushi Saito
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Olga Pletnikova
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Gay L Rudow
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Yumi Irie
- Division of Food Science & Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yang An
- Laboratory of Behavioral Neuroscience, NIH/NIA/IRP, Baltimore, MD, USA
| | - Kazuma Murakami
- Division of Food Science & Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kazuhiro Irie
- Division of Food Science & Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, NIH/NIA/IRP, Baltimore, MD, USA
| | - David R Fowler
- Office of the Chief Medical Examiner, Baltimore, MD, USA
| | - Lee J Martin
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Juan C Troncoso
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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100
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Takeuchi S, Ueda N, Suzuki K, Shimozawa N, Yasutomi Y, Kimura N. Elevated Membrane Cholesterol Disrupts Lysosomal Degradation to Induce β-Amyloid Accumulation: The Potential Mechanism Underlying Augmentation of β-Amyloid Pathology by Type 2 Diabetes Mellitus. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 189:391-404. [PMID: 30448407 DOI: 10.1016/j.ajpath.2018.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/14/2018] [Accepted: 10/04/2018] [Indexed: 01/05/2023]
Abstract
The endocytic membrane trafficking system is altered in the brains of early-stage Alzheimer disease (AD) patients, and endocytic disturbance affects the metabolism of β-amyloid (Aβ) protein, a key molecule in AD pathogenesis. It is widely accepted that type 2 diabetes mellitus (T2DM) is one of the strongest risk factors for development of AD. Supporting this link, experimentally induced T2DM enhances AD pathology in various animal models. Spontaneous T2DM also enhances Aβ pathology with severe endocytic pathology, even in nonhuman primate brains. However, it remains unclear how T2DM accelerates Aβ pathology. Herein, we demonstrate that cholesterol metabolism-related protein levels are increased and that membrane cholesterol level is elevated in spontaneous T2DM-affected cynomolgus monkey brains. Moreover, in vitro studies that manipulate cellular cholesterol reveal that elevated membrane cholesterol disrupts lysosomal degradation and enhances chemical-induced endocytic disturbance, resulting in great accumulation of Aβ in Neuro2a cells. These findings suggest that an alteration of cerebral cholesterol metabolism may be responsible for augmentation of Aβ pathology in T2DM-affected brains, which, in turn, may increase the risk for developing AD.
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Affiliation(s)
- Shingo Takeuchi
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Naoya Ueda
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Keiko Suzuki
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Nobuhiro Shimozawa
- Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, Tsukuba, Japan
| | - Yasuhiro Yasutomi
- Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, Tsukuba, Japan
| | - Nobuyuki Kimura
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Japan.
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