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Wurtz LI, Knyazhanskaya E, Sohaei D, Prassas I, Pittock S, Willrich MAV, Saadeh R, Gupta R, Atkinson HJ, Grill D, Stengelin M, Thebault S, Freedman MS, Diamandis EP, Scarisbrick IA. Identification of brain-enriched proteins in CSF as biomarkers of relapsing remitting multiple sclerosis. Clin Proteomics 2024; 21:42. [PMID: 38880880 PMCID: PMC11181608 DOI: 10.1186/s12014-024-09494-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 06/05/2024] [Indexed: 06/18/2024] Open
Abstract
BACKGROUND Multiple sclerosis (MS) is a clinically and biologically heterogenous disease with currently unpredictable progression and relapse. After the development and success of neurofilament as a cerebrospinal fluid (CSF) biomarker, there is reinvigorated interest in identifying other markers of or contributors to disease. The objective of this study is to probe the predictive potential of a panel of brain-enriched proteins on MS disease progression and subtype. METHODS This study includes 40 individuals with MS and 14 headache controls. The MS cohort consists of 20 relapsing remitting (RR) and 20 primary progressive (PP) patients. The CSF of all individuals was analyzed for 63 brain enriched proteins using a method of liquid-chromatography tandem mass spectrometry. Wilcoxon rank sum test, Kruskal-Wallis one-way ANOVA, logistic regression, and Pearson correlation were used to refine the list of candidates by comparing relative protein concentrations as well as relation to known imaging and molecular biomarkers. RESULTS We report 30 proteins with some relevance to disease, clinical subtype, or severity. Strikingly, we observed widespread protein depletion in the disease CSF as compared to control. We identified numerous markers of relapsing disease, including KLK6 (kallikrein 6, OR = 0.367, p < 0.05), which may be driven by active disease as defined by MRI enhancing lesions. Other oligodendrocyte-enriched proteins also appeared at reduced levels in relapsing disease, namely CNDP1 (carnosine dipeptidase 1), LINGO1 (leucine rich repeat and Immunoglobin-like domain-containing protein 1), MAG (myelin associated glycoprotein), and MOG (myelin oligodendrocyte glycoprotein). Finally, we identified three proteins-CNDP1, APLP1 (amyloid beta precursor like protein 1), and OLFM1 (olfactomedin 1)-that were statistically different in relapsing vs. progressive disease raising the potential for use as an early biomarker to discriminate clinical subtype. CONCLUSIONS We illustrate the utility of targeted mass spectrometry in generating potential targets for future biomarker studies and highlight reductions in brain-enriched proteins as markers of the relapsing remitting disease stage.
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Affiliation(s)
- Lincoln I Wurtz
- Medical Scientist Training Program, Mayo Clinic, Rochester, MN, USA
- Mayo Clinic Alix School of Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Dorsa Sohaei
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Ioannis Prassas
- Mount Sinai Hospital, Toronto, Canada
- Laboratory Medicine Program, University Health Network, Toronto, Canada
| | - Sean Pittock
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
- Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, Rochester, MN, USA
| | | | - Ruba Saadeh
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ruchi Gupta
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Hunter J Atkinson
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Diane Grill
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | | | - Simon Thebault
- Department of Medicine and The Ottawa Research Institute, Ottawa, Canada
- Division of Multiple Sclerosis, Department of Neurology, The University of Pennsylvania, Philadelphia, USA
| | - Mark S Freedman
- Department of Medicine and The Ottawa Research Institute, Ottawa, Canada
| | | | - Isobel A Scarisbrick
- Center for Multiple Sclerosis and Autoimmune Neurology, Mayo Clinic, Rochester, MN, USA.
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, 55905, USA.
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Moser C, Guschtschin-Schmidt N, Silber M, Flum J, Muhle-Goll C. Substrate Selection Criteria in Regulated Intramembrane Proteolysis. ACS Chem Neurosci 2024; 15:1321-1334. [PMID: 38525994 DOI: 10.1021/acschemneuro.4c00068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024] Open
Abstract
Alzheimer's disease is the most common form of dementia encountered in an aging population. Characteristic amyloid deposits of Aβ peptides in the brain are generated through cleavage of amyloid precursor protein (APP) by γ-secretase, an intramembrane protease. Cryo-EM structures of substrate γ-secretase complexes revealed details of the process, but how substrates are recognized and enter the catalytic site is still largely ignored. γ-Secretase cleaves a diverse range of substrate sequences without a common consensus sequence, but strikingly, single point mutations within the transmembrane domain (TMD) of specific substrates may greatly affect cleavage efficiencies. Previously, conformational flexibility was hypothesized to be the main criterion for substrate selection. Here we review the 3D structure and dynamics of several γ-secretase substrate TMDs and compare them with mutants shown to affect the cleavage efficiency. In addition, we present structural and dynamic data on ITGB1, a known nonsubstrate of γ-secretase. A comparison of biophysical details between these TMDs and changes generated by introducing crucial mutations allowed us to unravel common principles that differ between substrates and nonsubstrates. We identified three motifs in the investigated substrates: a highly flexible transmembrane domain, a destabilization of the cleavage region, and a basic signature at the end of the transmembrane helix. None of these appears to be exclusive. While conformational flexibility on its own may increase cleavage efficiency in well-known substrates like APP or Notch1, our data suggest that the three motifs seem to be rather variably combined to determine whether a transmembrane helix is efficiently recognized as a γ-secretase substrate.
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Affiliation(s)
- Celine Moser
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Nadja Guschtschin-Schmidt
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Mara Silber
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Julia Flum
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Claudia Muhle-Goll
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
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3
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Sarkar D, Bhunia A. Delineating the Role of GxxxG Motif in Amyloidogenesis: A New Perspective in Targeting Amyloid-Beta Mediated AD Pathogenesis. ACS BIO & MED CHEM AU 2024; 4:4-19. [PMID: 38404748 PMCID: PMC10885112 DOI: 10.1021/acsbiomedchemau.3c00055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 02/27/2024]
Abstract
The pursuit of a novel structural motif that can shed light on the key functional attributes is a primary focus in the study of protein folding disorders. Decades of research on Alzheimer's disease (AD) have centered on the Amyloid β (Aβ) pathway, highlighting its significance in understanding the disorder. The diversity in the Aβ pathway and the possible silent tracks which are yet to discover, makes it exceedingly intimidating to the interdisciplinary scientific community. Over the course of AD research, Aβ has consistently been at the forefront of scientific inquiry and discussion. In this review, we epitomize the role of a potential structural motif (GxxxG motif) that may provide a new horizon to the Aβ conflict. We emphasize on how comprehensive understanding of this motif from a structure-function perspective may pave the way for designing novel therapeutics intervention in AD and related diseases.
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Affiliation(s)
- Dibakar Sarkar
- Department of Chemical Sciences, Bose Institute, Unified Academic Campus, Sector V, Salt Lake EN
80, Kolkata 700 091, India
| | - Anirban Bhunia
- Department of Chemical Sciences, Bose Institute, Unified Academic Campus, Sector V, Salt Lake EN
80, Kolkata 700 091, India
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Chau DDL, Ng LLH, Zhai Y, Lau KF. Amyloid precursor protein and its interacting proteins in neurodevelopment. Biochem Soc Trans 2023; 51:1647-1659. [PMID: 37387352 PMCID: PMC10629809 DOI: 10.1042/bst20221527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Amyloid precursor protein (APP) is a key molecule in the pathogenesis of Alzheimer's disease (AD) as the pathogenic amyloid-β peptide is derived from it. Two closely related APP family proteins (APPs) have also been identified in mammals. Current knowledge, including genetic analyses of gain- and loss-of-function mutants, highlights the importance of APPs in various physiological functions. Notably, APPs consist of multiple extracellular and intracellular protein-binding regions/domains. Protein-protein interactions are crucial for many cellular processes. In past decades, many APPs interactors have been identified which assist the revelation of the putative roles of APPs. Importantly, some of these interactors have been shown to influence several APPs-mediated neuronal processes which are found defective in AD and other neurodegenerative disorders. Studying APPs-interactor complexes would not only advance our understanding of the physiological roles of APPs but also provide further insights into the association of these processes to neurodegeneration, which may lead to the development of novel therapies. In this mini-review, we summarize the roles of APPs-interactor complexes in neurodevelopmental processes including neurogenesis, neurite outgrowth, axonal guidance and synaptogenesis.
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Affiliation(s)
- Dennis Dik-Long Chau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Laura Lok-Haang Ng
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yuqi Zhai
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
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5
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Schilling S, August A, Meleux M, Conradt C, Tremmel LM, Teigler S, Adam V, Müller UC, Koo EH, Kins S, Eggert S. APP family member dimeric complexes are formed predominantly in synaptic compartments. Cell Biosci 2023; 13:141. [PMID: 37533067 PMCID: PMC10398996 DOI: 10.1186/s13578-023-01092-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/21/2023] [Indexed: 08/04/2023] Open
Abstract
BACKGROUND The amyloid precursor protein (APP), a key player in Alzheimer's disease (AD), is part of a larger gene family, including the APP like proteins APLP1 and APLP2. They share similar structures, form homo- and heterotypic dimers and exhibit overlapping functions. RESULTS We investigated complex formation of the APP family members via two inducible dimerization systems, the FKBP-rapamycin based dimerization as well as cysteine induced dimerization, combined with co-immunoprecipitations and Blue Native (BN) gel analyses. Within the APP family, APLP1 shows the highest degree of dimerization and high molecular weight (HMW) complex formation. Interestingly, only about 20% of APP is dimerized in cultured cells whereas up to 50% of APP is dimerized in mouse brains, independent of age and splice forms. Furthermore, we could show that dimerized APP originates mostly from neurons and is enriched in synaptosomes. Finally, BN gel analysis of human cortex samples shows a significant decrease of APP dimers in AD patients compared to controls. CONCLUSIONS Together, we suggest that loss of full-length APP dimers might correlate with loss of synapses in the process of AD.
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Affiliation(s)
- Sandra Schilling
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Alexander August
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Mathieu Meleux
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Carolin Conradt
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Luisa M Tremmel
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
- Medical, Biochemistry & Molecular Biology, Center for Molecular Signaling (PZMS), Saarland University, 66421, Homburg, Germany
| | - Sandra Teigler
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Virginie Adam
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Ulrike C Müller
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, 69120, Heidelberg, Germany
| | - Edward H Koo
- Department of Neuroscience, University of California, San Diego (UCSD), La Jolla, CA, 92093-0662, USA
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany.
- Department of Neurogenetics, Max-Planck-Institute for Multidisciplinary Sciences, City-Campus, Hermann-Rein-Str. 3, 37075, Göttingen, Germany.
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6
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Hou X, Zhang X, Zou H, Guan M, Fu C, Wang W, Zhang ZR, Geng Y, Chen Y. Differential and substrate-specific inhibition of γ-secretase by the C-terminal region of ApoE2, ApoE3, and ApoE4. Neuron 2023; 111:1898-1913.e5. [PMID: 37040764 DOI: 10.1016/j.neuron.2023.03.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/16/2023] [Accepted: 03/17/2023] [Indexed: 04/13/2023]
Abstract
Aberrant low γ-secretase activity is associated with most of the presenilin mutations that underlie familial Alzheimer's disease (fAD). However, the role of γ-secretase in the more prevalent sporadic AD (sAD) remains unaddressed. Here, we report that human apolipoprotein E (ApoE), the most important genetic risk factor of sAD, interacts with γ-secretase and inhibits it with substrate specificity in cell-autonomous manners through its conserved C-terminal region (CT). This ApoE CT-mediated inhibitory activity is differentially compromised in different ApoE isoforms, resulting in an ApoE2 > ApoE3 > ApoE4 potency rank order inversely correlating to their associated AD risk. Interestingly, in an AD mouse model, neuronal ApoE CT migrates to amyloid plaques in the subiculum from other regions and alleviates the plaque burden. Together, our data reveal a hidden role of ApoE as a γ-secretase inhibitor with substrate specificity and suggest that this precision γ-inhibition by ApoE may protect against the risk of sAD.
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Affiliation(s)
- Xianglong Hou
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuexin Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huan Zou
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingfeng Guan
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoying Fu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China
| | - Wenyuan Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China
| | - Zai-Rong Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China
| | - Yang Geng
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China.
| | - Yelin Chen
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 100 Haike Rd., B13, Pudongxinqu, Shanghai 201210, China.
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7
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Yanagida K, Maruyama R, Tagami S, Kudo T, Okochi M, Fukumori A. APLP2 is predominantly cleaved by β-secretase and γ-secretase in the human brain. Psychogeriatrics 2023; 23:311-318. [PMID: 36691315 DOI: 10.1111/psyg.12933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 12/25/2022] [Accepted: 01/03/2023] [Indexed: 01/25/2023]
Abstract
BACKGROUND Amyloid-β peptide is well-known as a pathogen of Alzheimer's disease, but its precursor, amyloid-beta precursor protein (APP), remains unexplained 30 years after its discovery. APP has two homologues called amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2), and shares a similar structural organisation with them and has partially overlapping functions. APP family proteins are essential for survival, shown by the crossbreeding analysis of knockout mice of APP family molecules, including APLP1 and APLP2. APLP2 is known to play the most important role among them, but the molecular metabolism of APLP2 is only partially understood. Here, we analysed ectodomain shedding and γ-secretase cleavage of APLP2 by molecular biological and biochemical techniques. METHOD We analysed the culture supernatant of HEK293 cells overexpressing APLP2 and human cerebrospinal fluid. For the analysis of secreted APLP2 fragments, we raised the OA603 antibody that reacts with the juxtamembrane domain of APLP2. Substrate cleavage sites were identified by matrix assisted laser desorption/ionisation mass spectrometry. RESULTS By overexpressing in HEK293 cells, APLP2 undergoes ectodomain shedding at three sites in the extracellular region by α- and β-secretase-like activity and then is intramembranously cleaved at three sites by γ-secretase. In particular, in shedding, α-secretase-like activity was dominant in HEK cells. Surprisingly, in human cerebrospinal fluid, APLP2-derived metabolic fragments were mainly cleaved by β-secretase-like activity, not by α-secretase-like activity. Because APP is also mainly cleaved by beta-site amyloid precursor protein cleaving enzyme 1 in neurons and APLP1 is expressed exclusively in neurons, these findings suggest that APP family proteins may play a common role via β-secretase-like cleavage in the central nerve system. CONCLUSIONS Thus, these findings may contribute to a better understanding of the role of APP family proteins in Alzheimer's disease.
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Affiliation(s)
- Kanta Yanagida
- Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan.,Department of Pharmacotherapeutics II, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.,Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Riki Maruyama
- Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan.,Department of Pharmacotherapeutics II, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Japan
| | - Shinji Tagami
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Takashi Kudo
- Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan
| | - Masayasu Okochi
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Akio Fukumori
- Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan.,Department of Pharmacotherapeutics II, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.,Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan.,Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, Obu, Japan
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8
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Sato H, Kasuga K, Isoo N, Hayashi T, Ikeuchi T, Hori Y, Tomita T. Soluble form of the APP fragment, sAPPβ, positively regulates tau secretion. Neurosci Res 2023:S0168-0102(23)00068-8. [PMID: 36967088 DOI: 10.1016/j.neures.2023.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 04/05/2023]
Abstract
Extracellular tau has been highlighted in the pathogenesis of Alzheimer disease (AD), which is the most common neurodegenerative disease. Pathological analyses as well as model animal studies suggest that amyloid-β peptide (Aβ) deposition facilitates the spreading of tau aggregation pathology via extracellular tau. However, the precise mechanism of tau secretion remains unknown. Here, we show that the overexpression of amyloid precursor protein (APP) enhances the secretion of tau phosphorylated at threonine 181 in mouse neuroblastoma Neuro2a cells. Moreover, we found that soluble amyloid precursor protein β (sAPPβ), which is generated by β-site APP cleaving enzyme 1 (BACE1), mediates tau secretion. Our results demonstrate that BACE1-mediated cleavage of APP plays pathological roles in AD pathogenesis by not only Aβ production, but by the spreading of tau aggregation pathology via sAPPβ in AD patients.
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Affiliation(s)
- Haruaki Sato
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Kensaku Kasuga
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, Japan
| | - Noriko Isoo
- Department of Physiology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Toshihiro Hayashi
- Department of Physiology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, Japan
| | - Yukiko Hori
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
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Singh A, Yeates C, Deshpande P, Kango-Singh M. Signaling interactions among neurons impact cell fitness and death in Alzheimer’s disease. Neural Regen Res 2023; 18:784-789. [DOI: 10.4103/1673-5374.354516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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10
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Huang Z. A Function of Amyloid-β in Mediating Activity-Dependent Axon/Synapse Competition May Unify Its Roles in Brain Physiology and Pathology. J Alzheimers Dis 2023; 92:29-57. [PMID: 36710681 PMCID: PMC10023438 DOI: 10.3233/jad-221042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Amyloid-β protein precursor (AβPP) gives rise to amyloid-β (Aβ), a peptide at the center of Alzheimer's disease (AD). AβPP, however, is also an ancient molecule dating back in evolution to some of the earliest forms of metazoans. This suggests a possible ancestral function that may have been obscured by those that evolve later. Based on literature from the functions of Aβ/AβPP in nervous system development, plasticity, and disease, to those of anti-microbial peptides (AMPs) in bacterial competition as well as mechanisms of cell competition uncovered first by Drosophila genetics, I propose that Aβ/AβPP may be part of an ancient mechanism employed in cell competition, which is subsequently co-opted during evolution for the regulation of activity-dependent neural circuit development and plasticity. This hypothesis is supported by foremost the high similarities of Aβ to AMPs, both of which possess unique, opposite (i.e., trophic versus toxic) activities as monomers and oligomers. A large body of data further suggests that the different Aβ oligomeric isoforms may serve as the protective and punishment signals long predicted to mediate activity-dependent axonal/synaptic competition in the developing nervous system and that the imbalance in their opposite regulation of innate immune and glial cells in the brain may ultimately underpin AD pathogenesis. This hypothesis can not only explain the diverse roles observed of Aβ and AβPP family molecules, but also provide a conceptual framework that can unify current hypotheses on AD. Furthermore, it may explain major clinical observations not accounted for and identify approaches for overcoming shortfalls in AD animal modeling.
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Affiliation(s)
- Zhen Huang
- Departments of Neuroscience and Neurology, University of Wisconsin-Madison, Madison, WI, USA
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11
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Guanidine-based β amyloid precursor protein cleavage enzyme 1 (BACE-1) inhibitors for the Alzheimer's disease (AD): A review. Bioorg Med Chem 2022; 74:117047. [DOI: 10.1016/j.bmc.2022.117047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/16/2022] [Accepted: 10/04/2022] [Indexed: 11/02/2022]
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12
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Papadopoulos N, Suelves N, Perrin F, Vadukul DM, Vrancx C, Constantinescu SN, Kienlen-Campard P. Structural Determinant of β-Amyloid Formation: From Transmembrane Protein Dimerization to β-Amyloid Aggregates. Biomedicines 2022; 10:2753. [PMID: 36359274 PMCID: PMC9687742 DOI: 10.3390/biomedicines10112753] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 10/03/2023] Open
Abstract
Most neurodegenerative diseases have the characteristics of protein folding disorders, i.e., they cause lesions to appear in vulnerable regions of the nervous system, corresponding to protein aggregates that progressively spread through the neuronal network as the symptoms progress. Alzheimer's disease is one of these diseases. It is characterized by two types of lesions: neurofibrillary tangles (NFTs) composed of tau proteins and senile plaques, formed essentially of amyloid peptides (Aβ). A combination of factors ranging from genetic mutations to age-related changes in the cellular context converge in this disease to accelerate Aβ deposition. Over the last two decades, numerous studies have attempted to elucidate how structural determinants of its precursor (APP) modify Aβ production, and to understand the processes leading to the formation of different Aβ aggregates, e.g., fibrils and oligomers. The synthesis proposed in this review indicates that the same motifs can control APP function and Aβ production essentially by regulating membrane protein dimerization, and subsequently Aβ aggregation processes. The distinct properties of these motifs and the cellular context regulate the APP conformation to trigger the transition to the amyloid pathology. This concept is critical to better decipher the patterns switching APP protein conformation from physiological to pathological and improve our understanding of the mechanisms underpinning the formation of amyloid fibrils that devastate neuronal functions.
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Affiliation(s)
- Nicolas Papadopoulos
- SIGN Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium
- Ludwig Institute for Cancer Research Brussels, 1348 Brussels, Belgium
| | - Nuria Suelves
- Aging and Dementia Research Group, Cellular and Molecular (CEMO) Division, Institute of Neuroscience, UCLouvain, 1200 Brussels, Belgium
| | - Florian Perrin
- Memory Disorders Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Devkee M. Vadukul
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London SW7 2BX, UK
| | - Céline Vrancx
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Stefan N. Constantinescu
- SIGN Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium
- Ludwig Institute for Cancer Research Brussels, 1348 Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
- Nuffield Department of Medicine, Ludwig Institute for Cancer Research, Oxford University, Oxford OX1 2JD, UK
| | - Pascal Kienlen-Campard
- Aging and Dementia Research Group, Cellular and Molecular (CEMO) Division, Institute of Neuroscience, UCLouvain, 1200 Brussels, Belgium
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13
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Jeong A, Auger SA, Maity S, Fredriksen K, Zhong R, Li L, Distefano MD. In Vivo Prenylomic Profiling in the Brain of a Transgenic Mouse Model of Alzheimer's Disease Reveals Increased Prenylation of a Key Set of Proteins. ACS Chem Biol 2022; 17:2863-2876. [PMID: 36109170 PMCID: PMC9799064 DOI: 10.1021/acschembio.2c00486] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Dysregulation of protein prenylation has been implicated in many diseases, including Alzheimer's disease (AD). Prenylomic analysis, the combination of metabolic incorporation of an isoprenoid analogue (C15AlkOPP) into prenylated proteins with a bottom-up proteomic analysis, has allowed the identification of prenylated proteins in various cellular models. Here, transgenic AD mice were administered with C15AlkOPP through intracerebroventricular (ICV) infusion over 13 days. Using prenylomic analysis, 36 prenylated proteins were enriched in the brains of AD mice. Importantly, the prenylated forms of 15 proteins were consistently upregulated in AD mice compared to nontransgenic wild-type controls. These results highlight the power of this in vivo metabolic labeling approach to identify multiple post-translationally modified proteins that may serve as potential therapeutic targets for a disease that has proved refractory to treatment thus far. Moreover, this method should be applicable to many other types of protein modifications, significantly broadening its scope.
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Affiliation(s)
- Angela Jeong
- University of Minnesota, Minneapolis, MN, 55455 USA
| | | | - Sanjay Maity
- University of Minnesota, Minneapolis, MN, 55455 USA
| | | | - Rui Zhong
- University of Minnesota, Minneapolis, MN, 55455 USA
| | - Ling Li
- University of Minnesota, Minneapolis, MN, 55455 USA
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14
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Biberoglu K, Yuksel M, Onder S, Tacal O. Effects of toluidine blue O and methylene blue on growth and viability of pancreatic cancer cells. Drug Dev Res 2022; 83:900-909. [PMID: 35092039 DOI: 10.1002/ddr.21915] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/10/2022] [Accepted: 01/15/2022] [Indexed: 12/17/2023]
Abstract
Amyloid precursor-like protein-2 (APLP2) and its C-terminal fragments (CTFs) are expressed at high levels in pancreatic cancer cells and knockdown of APLP2 expression inhibits tumor growth. CTFs are released from APLP2 by beta-secretase (BACE). In this study, our goal was to determine whether methylene blue (MethB) and toluidine blue O (TBO) could be used to slow down the growth and viability of pancreatic cancer cells (Hs 766T). We found that TBO and MethB decreased the growth and viability of Hs 766T cells in a dose- and time-dependent manner compared to vehicle-treated control, as demonstrated by MTT and trypan blue exclusion assays. Although TBO led to decreased expression of APLP2, MethB did not show any significant effect on APLP2. However, both MethB and TBO reduced BACE activity and the levels of APLP2 CTFs in Hs 766T cells. In conclusion, MethB and TBO may be valuable candidates for the treatment of pancreatic cancer by targeting APLP2 processing.
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Affiliation(s)
- Kevser Biberoglu
- Department of Biochemistry, School of Pharmacy, Hacettepe University, Ankara, Turkey
| | - Melike Yuksel
- Department of Biochemistry, School of Pharmacy, Hacettepe University, Ankara, Turkey
| | - Seda Onder
- Department of Biochemistry, School of Pharmacy, Hacettepe University, Ankara, Turkey
| | - Ozden Tacal
- Department of Biochemistry, School of Pharmacy, Hacettepe University, Ankara, Turkey
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15
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Li J, Wang Z, Lubritz D, Arango J, Fulton J, Settar P, Rowland K, Cheng H, Wolc A. Genome-wide association studies for egg quality traits in White Leghorn layers using low-pass sequencing and SNP chip data. J Anim Breed Genet 2022; 139:380-397. [PMID: 35404478 DOI: 10.1111/jbg.12679] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/05/2022] [Accepted: 03/27/2022] [Indexed: 12/24/2022]
Abstract
Low-pass sequencing data have been proposed as an alternative to single nucleotide polymorphism (SNP) chips in genome-wide association studies (GWAS) of several species. However, it has not been used in layer chickens yet. This study aims at comparing the GWAS results of White Leghorn chickens using low-pass sequencing data (1×) and 54 k SNP chip data. Ten commercially relevant egg quality traits including albumen height, shell strength, shell colour, egg weight and yolk weight collected from up to 1,420 White Leghorn chickens were analysed. The results showed that the genomic heritability estimates based on low-pass sequencing data were higher than those based on SNP chip data. Although two GWAS analyses showed similar overall landscape for most traits, low-pass sequencing captured some significant SNPs that were not on the SNP chip. In GWAS analysis using 54 k SNP chip data, after including more individuals (up to 5,700), additional significant SNPs not detected by low-pass sequencing data were found. In conclusion, GWAS using low-pass sequencing data showed similar results to those with SNP chip data and may require much larger sample sizes to show measurable advantages.
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Affiliation(s)
- Jinghui Li
- Department of Animal Science, University of California, Davis, California, USA
| | - Zigui Wang
- Department of Animal Science, University of California, Davis, California, USA
| | | | | | | | | | | | - Hao Cheng
- Department of Animal Science, University of California, Davis, California, USA
| | - Anna Wolc
- Hy-Line International, Dallas Center, Iowa, USA.,Department of Animal Science, Iowa State University, Ames, Iowa, USA
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16
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Finding New Ways How to Control BACE1. J Membr Biol 2022; 255:293-318. [PMID: 35305135 DOI: 10.1007/s00232-022-00225-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 02/24/2022] [Indexed: 01/18/2023]
Abstract
Recently, all applications of BACE1 inhibitors failed as therapeutical targets for Alzheimer´s disease (AD) due to severe side effects. Therefore, alternative ways for treatment development are a hot research topic. The present analysis investigates BACE1 protein-protein interaction networks and attempts to solve the absence of complete knowledge about pathways involving BACE1. A bioinformatics analysis matched the functions of the non-substrate interaction network with Voltage-gated potassium channels, which also appear as top priority protein nodes. Targeting BACE1 interactions with PS1 and GGA-s, blocking of BACE1 access to APP by BRI3 and RTN-s, activation of Wnt signaling and upregulation of β-catenin, and brain delivery of the extracellular domain of p75NTR, are the main alternatives to the use of BACE 1 inhibitors highlighted by the analysis. The pathway enrichment analysis also emphasized substrates and substrate candidates with essential biological functions, which cleavage must remain controlled. They include ephrin receptors, ROBO1, ROBO2, CNTN-s, CASPR-s, CD147, CypB, TTR, APLP1/APLP2, NRXN-s, and PTPR-s. The analysis of the interaction subnetwork of BACE1 functionally related to inflammation identified a connection to three cardiomyopathies, which supports the hypothesis of the common molecular mechanisms with AD. A lot of potential shows the regulation of BACE1 activity through post-translational modifications. The interaction network of BACE1 and its phosphorylation enzyme CSNK1D functionally match the Circadian clock, p53, and Hedgehog signaling pathways. The regulation of BACE1 glycosylation could be achieved through N-acetylglucosamine transferases, α-(1→6)-fucosyltransferase, β-galactoside α-(2→6)-sialyltransferases, galactosyltransferases, and mannosidases suggested by the interaction network analysis of BACE1-MGAT3. The present analysis proposes possibilities for the alternative control of AD pathology.
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17
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Song XJ, Zhou HY, Sun YY, Huang HC. Phosphorylation and Glycosylation of Amyloid-β Protein Precursor: The Relationship to Trafficking and Cleavage in Alzheimer's Disease. J Alzheimers Dis 2021; 84:937-957. [PMID: 34602469 DOI: 10.3233/jad-210337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder in the central nervous system, and this disease is characterized by extracellular senile plaques and intracellular neurofibrillary tangles. Amyloid-β (Aβ) peptide is the main constituent of senile plaques, and this peptide is derived from the amyloid-β protein precursor (AβPP) through the successive cleaving by β-site AβPP-cleavage enzyme 1 (BACE1) and γ-secretase. AβPP undergoes the progress of post-translational modifications, such as phosphorylation and glycosylation, which might affect the trafficking and the cleavage of AβPP. In the recent years, about 10 phosphorylation sites of AβPP were identified, and they play complex roles in glycosylation modification and cleavage of AβPP. In this article, we introduced the transport and the cleavage pathways of AβPP, then summarized the phosphorylation and glycosylation sites of AβPP, and further discussed the links and relationship between phosphorylation and glycosylation on the pathways of AβPP trafficking and cleavage in order to provide theoretical basis for AD research.
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Affiliation(s)
- Xi-Jun Song
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - He-Yan Zhou
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - Yu-Ying Sun
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
| | - Han-Chang Huang
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China.,Research Institute of Functional Factors and Brain Science, Beijing Union University, Beijing, China
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18
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Shah H, Patel A, Parikh V, Nagani A, Bhimani B, Shah U, Bambharoliya T. The β-Secretase Enzyme BACE1: A Biochemical Enigma for Alzheimer's Disease. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2021; 19:184-194. [PMID: 32452328 DOI: 10.2174/1871527319666200526144141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 04/18/2020] [Accepted: 04/29/2020] [Indexed: 01/08/2023]
Abstract
Beta site amyloid precursor protein cleaving enzyme 1 (BACE1) is a rational target in Alzheimer's Disease (AD) drug development due to its role in amyloidogenic cleavage of Amyloid Precursor Protein (APP) in generating Amyloid β (Aβ). This β-secretase cleaves not only Amyloid Precursor Protein (APP) and its homologues, but also small series of substrates including neuregulin and β subunit of voltage-gated sodium channel that play a very important role in the development and normal function of the brain. Moreover, BACE1 is modulated at the post-translational level by several factors that are associated with both physiological and pathological functions. Since the discovery of BACE1 over a decade ago, medicinal chemistry and pharmacokinetics of BACE1 small molecule inhibitors have proven challenging for the treatment of Alzheimer's disease.
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Affiliation(s)
- Hirak Shah
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat 391760, India
| | - Ashish Patel
- Ramanbhai Patel College of Pharmacy, Charotar University of Science and Technology, Changa, Gujarat 388421, India
| | - Vruti Parikh
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat 391760, India
| | - Afzal Nagani
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat 391760, India
| | - Bhargav Bhimani
- Piramal Discovery Solution, Pharmaceutical Special Economic Zone, Ahmedabad 382213, India
| | - Umang Shah
- Ramanbhai Patel College of Pharmacy, Charotar University of Science and Technology, Changa, Gujarat 388421, India
| | - Tushar Bambharoliya
- Pharmaceutical Polymer Technology, North Carolina State University, North Carolina, NC, United States
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19
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Rahman MM, Lendel C. Extracellular protein components of amyloid plaques and their roles in Alzheimer's disease pathology. Mol Neurodegener 2021; 16:59. [PMID: 34454574 PMCID: PMC8400902 DOI: 10.1186/s13024-021-00465-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 06/11/2021] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is pathologically defined by the presence of fibrillar amyloid β (Aβ) peptide in extracellular senile plaques and tau filaments in intracellular neurofibrillary tangles. Extensive research has focused on understanding the assembly mechanisms and neurotoxic effects of Aβ during the last decades but still we only have a brief understanding of the disease associated biological processes. This review highlights the many other constituents that, beside Aβ, are accumulated in the plaques, with the focus on extracellular proteins. All living organisms rely on a delicate network of protein functionality. Deposition of significant amounts of certain proteins in insoluble inclusions will unquestionably lead to disturbances in the network, which may contribute to AD and copathology. This paper provide a comprehensive overview of extracellular proteins that have been shown to interact with Aβ and a discussion of their potential roles in AD pathology. Methods that can expand the knowledge about how the proteins are incorporated in plaques are described. Top-down methods to analyze post-mortem tissue and bottom-up approaches with the potential to provide molecular insights on the organization of plaque-like particles are compared. Finally, a network analysis of Aβ-interacting partners with enriched functional and structural key words is presented.
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Affiliation(s)
- M Mahafuzur Rahman
- Department of Chemistry, KTH Royal Institute of Technology, SE-100 44, Stockholm, Sweden.
| | - Christofer Lendel
- Department of Chemistry, KTH Royal Institute of Technology, SE-100 44, Stockholm, Sweden.
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20
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Soto-Ospina A, Araque Marín P, Bedoya G, Sepulveda-Falla D, Villegas Lanau A. Protein Predictive Modeling and Simulation of Mutations of Presenilin-1 Familial Alzheimer's Disease on the Orthosteric Site. Front Mol Biosci 2021; 8:649990. [PMID: 34150846 PMCID: PMC8206637 DOI: 10.3389/fmolb.2021.649990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/22/2021] [Indexed: 11/13/2022] Open
Abstract
Alzheimer's disease pathology is characterized by β-amyloid plaques and neurofibrillary tangles. Amyloid precursor protein is processed by β and γ secretase, resulting in the production of β-amyloid peptides with a length ranging from 38 to 43 amino acids. Presenilin 1 (PS1) is the catalytic unit of γ-secretase, and more than 200 PS1 pathogenic mutations have been identified as causative for Alzheimer's disease. A complete monocrystal structure of PS1 has not been determined so far due to the presence of two flexible domains. We have developed a complete structural model of PS1 using a computational approach with structure prediction software. Missing fragments Met1-Glut72 and Ser290-Glu375 were modeled and validated by their energetic and stereochemical characteristics. Then, with the complete structure of PS1, we defined that these fragments do not have a direct effect in the structure of the pore. Next, we used our hypothetical model for the analysis of the functional effects of PS1 mutations Ala246GLu, Leu248Pro, Leu248Arg, Leu250Val, Tyr256Ser, Ala260Val, and Val261Phe, localized in the catalytic pore. For this, we used a quantum mechanics/molecular mechanics (QM/MM) hybrid method, evaluating modifications in the topology, potential surface density, and electrostatic potential map of mutated PS1 proteins. We found that each mutation exerts changes resulting in structural modifications of the active site and in the shape of the pore. We suggest this as a valid approach for functional studies of PS1 in view of the possible impact in substrate processing and for the design of targeted therapeutic strategies.
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Affiliation(s)
- Alejandro Soto-Ospina
- Faculty of Medicine, Group Molecular Genetics, University of Antioquia, Medellín, Colombia
- Faculty of Medicine, Group Neuroscience of Antioquia, University of Antioquia, Medellín, Colombia
| | - Pedronel Araque Marín
- School of Life Sciences, Research and Innovation in Chemistry Formulations Group, EIA University, Envigado, Colombia
| | - Gabriel Bedoya
- Faculty of Medicine, Group Molecular Genetics, University of Antioquia, Medellín, Colombia
| | - Diego Sepulveda-Falla
- Faculty of Medicine, Group Neuroscience of Antioquia, University of Antioquia, Medellín, Colombia
- Molecular Neuropathology of Alzheimer’s Disease, Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrés Villegas Lanau
- Faculty of Medicine, Group Molecular Genetics, University of Antioquia, Medellín, Colombia
- Faculty of Medicine, Group Neuroscience of Antioquia, University of Antioquia, Medellín, Colombia
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21
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Onodera W, Asahi T, Sawamura N. Rapid evolution of mammalian APLP1 as a synaptic adhesion molecule. Sci Rep 2021; 11:11305. [PMID: 34050225 PMCID: PMC8163877 DOI: 10.1038/s41598-021-90737-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/17/2021] [Indexed: 01/10/2023] Open
Abstract
Amyloid precursor protein (APP) family members are involved in essential neuronal development including neurite outgrowth, neuronal migration and maturation of synapse and neuromuscular junction. Among the APP gene family members, amyloid precursor-like protein 1 (APLP1) is selectively expressed in neurons and has specialized functions during synaptogenesis. Although a potential role for APLP1 in neuronal evolution has been indicated, its precise evolutionary and functional contributions are unknown. This study shows the molecular evolution of the vertebrate APP family based on phylogenetic analysis, while contrasting the evolutionary differences within the APP family. Phylogenetic analysis showed 15 times higher substitution rate that is driven by positive selection at the stem branch of the mammalian APLP1, resulting in dissimilar protein sequences compared to APP/APLP2. Docking simulation identified one positively selected site in APLP1 that alters the heparin-binding site, which could affect its function, and dimerization rate. Furthermore, the evolutionary rate covariation between the mammalian APP family and synaptic adhesion molecules (SAMs) was confirmed, indicating that only APLP1 has evolved to gain synaptic adhesion property. Overall, our results suggest that the enhanced synaptogenesis property of APLP1 as one of the SAMs may have played a role in mammalian brain evolution.
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Affiliation(s)
- Wataru Onodera
- Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan
| | - Toru Asahi
- Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan.,Research Organization for Nano & Life Innovation, Waseda University, #03C309, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan
| | - Naoya Sawamura
- Research Organization for Nano & Life Innovation, Waseda University, #03C309, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo, 162-8480, Japan. .,Green Computing Systems Research Organization, Waseda University, Shinjuku, Japan.
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22
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Chen Z, Yu Q, Yu Q, Johnson J, Shipman R, Zhong X, Huang J, Asthana S, Carlsson C, Okonkwo O, Li L. In-depth Site-specific Analysis of N-glycoproteome in Human Cerebrospinal Fluid and Glycosylation Landscape Changes in Alzheimer's Disease. Mol Cell Proteomics 2021; 20:100081. [PMID: 33862227 PMCID: PMC8724636 DOI: 10.1016/j.mcpro.2021.100081] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/02/2021] [Accepted: 04/03/2021] [Indexed: 01/22/2023] Open
Abstract
As the body fluid that directly interchanges with the extracellular fluid of the central nervous system (CNS), cerebrospinal fluid (CSF) serves as a rich source for CNS-related disease biomarker discovery. Extensive proteome profiling has been conducted for CSF, but studies aimed at unraveling site-specific CSF N-glycoproteome are lacking. Initial efforts into site-specific N-glycoproteomics study in CSF yield limited coverage, hindering further experimental design of glycosylation-based disease biomarker discovery in CSF. In the present study, we have developed an N-glycoproteomic approach that combines enhanced N-glycopeptide sequential enrichment by hydrophilic interaction chromatography (HILIC) and boronic acid enrichment with electron transfer and higher-energy collision dissociation (EThcD) for large-scale intact N-glycopeptide analysis. The application of the developed approach to the analyses of human CSF samples enabled identifications of a total of 2893 intact N-glycopeptides from 511 N-glycosites and 285 N-glycoproteins. To our knowledge, this is the largest site-specific N-glycoproteome dataset reported for CSF to date. Such dataset provides molecular basis for a better understanding of the structure-function relationships of glycoproteins and their roles in CNS-related physiological and pathological processes. As accumulating evidence suggests that defects in glycosylation are involved in Alzheimer's disease (AD) pathogenesis, in the present study, a comparative in-depth N-glycoproteomic analysis was conducted for CSF samples from healthy control and AD patients, which yielded a comparable N-glycoproteome coverage but a distinct expression pattern for different categories of glycoforms, such as decreased fucosylation in AD CSF samples. Altered glycosylation patterns were detected for a number of N-glycoproteins including alpha-1-antichymotrypsin, ephrin-A3 and carnosinase CN1 etc., which serve as potentially interesting targets for further glycosylation-based AD study and may eventually lead to molecular elucidation of the role of glycosylation in AD progression.
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Affiliation(s)
- Zhengwei Chen
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin, USA
| | - Qinying Yu
- School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Qing Yu
- School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Jillian Johnson
- School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Richard Shipman
- Department of Applied Science, University of Wisconsin-Stout, Menomonie, Wisconsin, USA
| | - Xiaofang Zhong
- School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Junfeng Huang
- School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Sanjay Asthana
- School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Cynthia Carlsson
- School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Ozioma Okonkwo
- School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin, USA; School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA.
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23
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Rueeger H, Lueoend R, Machauer R, Veenstra SJ, Holzer P, Hurth K, Voegtle M, Frederiksen M, Rondeau JM, Tintelnot-Blomley M, Jacobson LH, Staufenbiel M, Laue G, Neumann U. Synthesis of the Potent, Selective, and Efficacious β-Secretase (BACE1) Inhibitor NB-360. J Med Chem 2021; 64:4677-4696. [PMID: 33844524 DOI: 10.1021/acs.jmedchem.0c02143] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Starting from lead compound 4, the 1,4-oxazine headgroup was optimized to improve potency and brain penetration. Focusing at the 6-position of the 5-amino-1,4-oxazine, the insertion of a Me and a CF3 group delivered an excellent pharmacological profile with a pKa of 7.1 and a very low P-gp efflux ratio enabling high central nervous system (CNS) penetration and exposure. Various synthetic routes to access BACE1 inhibitors bearing a 5-amino-6-methyl-6-(trifluoromethyl)-1,4-oxazine headgroup were investigated. Subsequent optimization of the P3 fragment provided the highly potent N-(3-((3R,6R)-5-amino-3,6-dimethyl-6-(trifluoromethyl)-3,6-dihydro-2H-1,4-oxazin-3-yl)-4-fluorophenyl)-5-cyano-3-methylpicolinamide 54 (NB-360), able to reduce significantly Aβ levels in mice, rats, and dogs in acute and chronic treatment regimens.
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24
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Live-cell monitoring of protein localization to membrane rafts using protein-fragment complementation. Biosci Rep 2021; 40:221616. [PMID: 31850494 PMCID: PMC6944658 DOI: 10.1042/bsr20191290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 12/13/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022] Open
Abstract
The plasma membrane consists of a variety of discrete domains differing from the surrounding membrane in composition and properties. Selective partitioning of protein to these microdomains is essential for membrane functioning and integrity. Studying the nanoscale size and dynamic nature of the membrane microdomains requires advanced imaging approaches with a high spatiotemporal resolution and, consequently, expensive and specialized equipment, unavailable for most researchers and unsuited for large-scale studies. Thus, understanding of protein partitioning to the membrane microdomains in health and disease is still hampered by the lack of inexpensive live-cell approaches with an appropriate spatial resolution. Here, we have developed a novel approach based on Gaussia princeps luciferase protein-fragment complementation assay to quantitively investigate protein partitioning to cholesterol and sphingomyelin-rich domains, sometimes called ‘lipid rafts’, in intact living cells with a high-spatial resolution. In the assay, the reporter construct, carrying one half of the luciferase protein, is targeted to lipid microdomains through the fused acetylation motif from Src-family kinase Fyn. A protein of interest carries the second half of the luciferase protein. Together, this serves as a reversible real-time sensor of raft recruitment for the studied protein. We demonstrated that the assay can efficiently detect the dynamic alterations in raft localization of two disease-associated proteins: Akt and APP. Importantly, this method can be used in high-throughput screenings and other large-scale studies in living cells. This inexpensive, and easy to implement raft localization assay will benefit all researchers interested in protein partitioning in rafts.
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25
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Vijayan D, Chandra R. Amyloid Beta Hypothesis in Alzheimer's Disease: Major Culprits and Recent Therapeutic Strategies. Curr Drug Targets 2021; 21:148-166. [PMID: 31385768 DOI: 10.2174/1389450120666190806153206] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/13/2019] [Accepted: 07/26/2019] [Indexed: 01/18/2023]
Abstract
Alzheimer's disease (AD) is one of the most common forms of dementia and has been a global concern for several years. Due to the multi-factorial nature of the disease, AD has become irreversible, fatal and imposes a tremendous socio-economic burden. Even though experimental medicines suggested moderate benefits, AD still lacks an effective treatment strategy for the management of symptoms or cure. Among the various hypotheses that describe development and progression of AD, the amyloid hypothesis has been a long-term adherent to the AD due to the involvement of various forms of Amyloid beta (Aβ) peptides in the impairment of neuronal and cognitive functions. Hence, majority of the drug discovery approaches in the past have focused on the prevention of the accumulation of Aβ peptides. Currently, there are several agents in the phase III clinical trials that target Aβ or the various macromolecules triggering Aβ deposition. In this review, we present the state of the art knowledge on the functional aspects of the key players involved in the amyloid hypothesis. Furthermore, we also discuss anti-amyloid agents present in the Phase III clinical trials.
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Affiliation(s)
- Dileep Vijayan
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Remya Chandra
- Department of Biotechnology and Microbiology, Thalassery Campus, Kannur University, Kerala Pin 670 661, India
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26
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Amiri A, Barreto G, Sathyapalan T, Sahebkar A. siRNA Therapeutics: Future Promise for Neurodegenerative Diseases. Curr Neuropharmacol 2021; 19:1896-1911. [PMID: 33797386 PMCID: PMC9185778 DOI: 10.2174/1570159x19666210402104054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/29/2021] [Accepted: 03/30/2021] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases (ND), as a group of central nervous system (CNS) disorders, are among the most prominent medical problems of the 21st century. They are often associated with considerable disability, motor dysfunction and dementia and are more common in the aged population. ND imposes a psychologic, economic and social burden on the patients and their families. Currently, there is no effective treatment for ND. Since many ND result from the gain of function of a mutant allele, small interference RNA (siRNA) can be a potential therapeutic agent for ND management. Based on the RNA interference (RNAi) approach, siRNA is a powerful tool for modulating gene expression through gene silencing. However, there are some obstacles in the clinical application of siRNA, including unfavorable immune response, off-target effects, instability of naked siRNA, nuclease susceptibility and a need to develop a suitable delivery system. Since there are some issues related to siRNA delivery routes, in this review, we focus on the application of siRNA in the management of ND treatment from 2000 to 2020.
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Affiliation(s)
| | | | | | - Amirhossein Sahebkar
- Address correspondence to this author at the Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Tel: 985118002288; Fax: 985118002287; E-mails: ;
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27
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Ovsepian SV, Horacek J, O'Leary VB, Hoschl C. The Ups and Downs of BACE1: Walking a Fine Line between Neurocognitive and Other Psychiatric Symptoms of Alzheimer's Disease. Neuroscientist 2020; 27:222-234. [PMID: 32713260 DOI: 10.1177/1073858420940943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although neurocognitive deficit is the best-recognized indicator of Alzheimer's disease (AD), psychotic and other noncognitive symptoms are the prime cause of institutionalization. BACE1 is the rate-limiting enzyme in the production of Aβ of AD, and one of the promising therapeutic targets in countering cognitive decline and amyloid pathology. Changes in BACE1 activity have also emerged to cause significant noncognitive neuropsychiatric symptoms and impairments of circadian rhythms, as evident from clinical trials and reports in transgenic models. In this study, we consider key characteristics of BACE1 with its contribution to neurocognitive deficit and other psychiatric symptoms of AD. We argue that a growing list of noncognitive mental impairments related to pharmacological modulation of BACE1 might present a major obstacle in clinical translation of emerging therapeutic leads targeting this protease. The adverse effects of BACE1 inhibition on mental health call for a revision of treatment strategies that assume indiscriminate inhibition of this key protease, and stress the need for further mechanistic and translational studies.
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Affiliation(s)
- Saak V Ovsepian
- National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague, Czech Republic.,International Centre for Neurotherapeutics, Dublin City University, Dublin, Ireland
| | - Jiri Horacek
- National Institute of Mental Health, Klecany, Czech Republic
| | - Valerie B O'Leary
- Department of Medical Genetics, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Cyril Hoschl
- National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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28
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Hu Y, Li H, Zhang J, Zhang X, Xia X, Qiu C, Liao Y, Chen H, Song Z, Zhou W. Periodontitis Induced by P. gingivalis-LPS Is Associated With Neuroinflammation and Learning and Memory Impairment in Sprague-Dawley Rats. Front Neurosci 2020; 14:658. [PMID: 32714134 PMCID: PMC7344110 DOI: 10.3389/fnins.2020.00658] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/27/2020] [Indexed: 12/19/2022] Open
Abstract
Background Periodontitis is one of the most common oral diseases and is a potential risk factor for systemic diseases. In this study, we aimed to investigate the association between periodontitis and learning and memory impairment. Methods We established a periodontitis model by topical application of Porphyromonas gingivalis lipopolysaccharide (P. gingivalis-LPS) into the palatal gingival sulcus of the maxillary first molars of 10-week-old male rats for a 10-week period. We assessed alveolar bone resorption using micro-computed tomography analysis and learning and memory ability using the Morris water maze test. We determined the levels of cytokines [interleukin (IL)-1β, IL-6, IL-8, and IL-21] and LPS in the peripheral blood and cortex, as well as toll-like receptor 4 (TLR4)/NF-κB signaling pathway activation, using reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and western blot. We determined activation of microglia and astrocytes, expression of Aβ1-42, APP and Tau by immunohistochemistry. Finally, we measured the expression of amyloid precursor protein (APP) and its key secretases, as well as the Aβ1-40/1-42 ratio, by RT-PCR, western blot, and ELISA. Results We found that periodontitis induced learning and memory impairment in the rats. Further, we observed that it induced significant alveolar bone resorption. There was an increase in the levels of inflammatory cytokines and LPS. Moreover, we confirmed TLR4/NF-κB signaling pathway activation. We also observed activated microglia and astrocytes with enlarged cell bodies and irregular protrusions. Finally, we observed the promotion of β- and γ-secretases APP processing. Conclusion Our findings indicated that periodontitis was associated with learning and memory impairment, probably induced by neuroinflammation via activating the TLR4/NF-κB signaling pathway. Furthermore, abnormal APP processing could be involved in this progress.
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Affiliation(s)
- Yi Hu
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Huxiao Li
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Jing Zhang
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Xu Zhang
- National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.,Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xinyi Xia
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Che Qiu
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Yue Liao
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Huiwen Chen
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Zhongchen Song
- Department of Periodontology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Wei Zhou
- National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.,Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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29
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Lanchec E, Désilets A, Béliveau F, Fontaine-Carbonneau C, Laniel A, Leduc R, Lavoie C. Matriptase processing of APLP1 ectodomain alters its homodimerization. Sci Rep 2020; 10:10091. [PMID: 32572095 PMCID: PMC7308337 DOI: 10.1038/s41598-020-67005-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/29/2020] [Indexed: 11/09/2022] Open
Abstract
The amyloid beta peptide (Aβ) is derived from the amyloid precursor protein (APP) by secretase processing. APP is also cleaved by numerous other proteases, such as the type II transmembrane serine protease matriptase, with consequences on the production of Aβ. Because the APP homolog protein amyloid-like protein 1 (APLP1) shares similarities with APP, we sought to determine if matriptase also plays a role in its processing. Here, we demonstrate that matriptase directly interacts with APLP1 and that APLP1 is cleaved in cellulo by matriptase in its E1 ectodomains at arginine 124. Replacing Arg124 with Ala abolished APLP1 processing by matriptase. Using a bioluminescence resonance energy transfer (BRET) assay we found that matriptase reduces APLP1 homodimeric interactions. This study identifies matriptase as the first protease cleaving APLP1 in its dimerization domain, potentially altering the multiple functions associated with dimer formation.
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Affiliation(s)
- Erwan Lanchec
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada
| | - Antoine Désilets
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada
| | - François Béliveau
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada
| | - Cloé Fontaine-Carbonneau
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada
| | - Andréanne Laniel
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada
| | - Richard Leduc
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada.
| | - Christine Lavoie
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H5N4, Canada.
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30
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Alam J, Sharma L. Potential Enzymatic Targets in Alzheimer's: A Comprehensive Review. Curr Drug Targets 2020; 20:316-339. [PMID: 30124150 DOI: 10.2174/1389450119666180820104723] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/23/2018] [Accepted: 08/15/2018] [Indexed: 12/13/2022]
Abstract
Alzheimer's, a degenerative cause of the brain cells, is called as a progressive neurodegenerative disease and appears to have a heterogeneous etiology with main emphasis on amyloid-cascade and hyperphosphorylated tau-cascade hypotheses, that are directly linked with macromolecules called enzymes such as β- & γ-secretases, colinesterases, transglutaminases, and glycogen synthase kinase (GSK-3), cyclin-dependent kinase (cdk-5), microtubule affinity-regulating kinase (MARK). The catalytic activity of the above enzymes is the result of cognitive deficits, memory impairment and synaptic dysfunction and loss, and ultimately neuronal death. However, some other enzymes also lead to these dysfunctional events when reduced to their normal activities and levels in the brain, such as α- secretase, protein kinase C, phosphatases etc; metabolized to neurotransmitters, enzymes like monoamine oxidase (MAO), catechol-O-methyltransferase (COMT) etc. or these abnormalities can occur when enzymes act by other mechanisms such as phosphodiesterase reduces brain nucleotides (cGMP and cAMP) levels, phospholipase A2: PLA2 is associated with reactive oxygen species (ROS) production etc. On therapeutic fronts, several significant clinical trials are underway by targeting different enzymes for development of new therapeutics to treat Alzheimer's, such as inhibitors for β-secretase, GSK-3, MAO, phosphodiesterase, PLA2, cholinesterases etc, modulators of α- & γ-secretase activities and activators for protein kinase C, sirtuins etc. The last decades have perceived an increasing focus on findings and search for new putative and novel enzymatic targets for Alzheimer's. Here, we review the functions, pathological roles, and worth of almost all the Alzheimer's associated enzymes that address to therapeutic strategies and preventive approaches for treatment of Alzheimer's.
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Affiliation(s)
- Jahangir Alam
- School of Pharmaceutical Sciences, Shoolini University, Solan, H.P., Pin 173229, India
| | - Lalit Sharma
- School of Pharmaceutical Sciences, Shoolini University, Solan, H.P., Pin 173229, India
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31
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The Interaction Between Contactin and Amyloid Precursor Protein and Its Role in Alzheimer’s Disease. Neuroscience 2020; 424:184-202. [DOI: 10.1016/j.neuroscience.2019.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 01/06/2023]
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32
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Lee YJ, Ch'ng TH. RIP at the Synapse and the Role of Intracellular Domains in Neurons. Neuromolecular Med 2019; 22:1-24. [PMID: 31346933 DOI: 10.1007/s12017-019-08556-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022]
Abstract
Regulated intramembrane proteolysis (RIP) occurs in a cell when transmembrane proteins are cleaved by intramembrane proteases such as secretases to generate soluble protein fragments in the extracellular environment and the cytosol. In the cytosol, these soluble intracellular domains (ICDs) have local functions near the site of cleavage or in many cases, translocate to the nucleus to modulate gene expression. While the mechanism of RIP is relatively well studied, the fate and function of ICDs for most substrate proteins remain poorly characterized. In neurons, RIP occurs in various subcellular compartments including at the synapse. In this review, we summarize current research on RIP in neurons, focusing specifically on synaptic proteins where the presence and function of the ICDs have been reported. We also briefly discuss activity-driven processing of RIP substrates at the synapse and the cellular machinery that support long-distance transport of ICDs from the synapse to the nucleus. Finally, we describe future challenges in this field of research in the context of understanding the contribution of ICDs in neuronal function.
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Affiliation(s)
- Yan Jun Lee
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore.,Interdisciplinary Graduate School (IGS), Nanyang Technological University, Singapore, Singapore
| | - Toh Hean Ch'ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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33
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Zhao L, Zhao Y, Tang FL, Xiong L, Su C, Mei L, Zhu XJ, Xiong WC. pHluorin-BACE1-mCherry Acts as a Reporter for the Intracellular Distribution of Active BACE1 In Vitro and In Vivo. Cells 2019; 8:E474. [PMID: 31108937 PMCID: PMC6562731 DOI: 10.3390/cells8050474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/09/2019] [Accepted: 05/15/2019] [Indexed: 12/23/2022] Open
Abstract
β-site APP-cleaving enzyme 1 (BACE1) initiates amyloid precursor protein (APP) cleavage and β-amyloid (Aβ) production, a critical step in the pathogenesis of Alzheimer's disease (AD). It is thus of considerable interest to investigate how BACE1 activity is regulated. BACE1 has its maximal activity at acidic pH and GFP variant-pHluorin-displays pH dependence. In light of these observations, we generated three tandem fluorescence-tagged BACE1 fusion proteins, named pHluorin-BACE1-mCherry, BACE1-mCherry-pHluorin and BACE1-mCherry-EGFP. Comparing the fluorescence characteristics of these proteins in response to intracellular pH changes induced by chloroquine or bafilomycin A1, we found that pHluorin-BACE1-mCherry is a better pH sensor for BACE1 because its fluorescence intensity responds to pH changes more dramatically and more quickly. Additionally, we found that (pro)renin receptor (PRR), a subunit of the v-ATPase complex, which is critical for maintaining vesicular pH, regulates pHluorin's fluorescence and BACE1 activity in pHluorin-BACE1-mCherry expressing cells. Finally, we found that the expression of Swedish mutant APP (APPswe) suppresses pHluorin fluorescence in pHluorin-BACE1-mCherry expressing cells in culture and in vivo, implicating APPswe not only as a substrate but also as an activator of BACE1. Taken together, these results suggest that the pHluorin-BACE1-mCherry fusion protein may serve as a useful tool for visualizing active/inactive BACE1 in culture and in vivo.
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Affiliation(s)
- Lu Zhao
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Yang Zhao
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Fu-Lei Tang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Lei Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Ce Su
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Xiao-Juan Zhu
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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Abstract
Alzheimer's disease (AD), the most common cause of age-dependent dementia, is one of the most significant healthcare problems worldwide. Aggravating this situation, drugs that are currently US Food and Drug Administration (FDA)-approved for AD treatment do not prevent or delay disease progression. Therefore, developing effective therapies for AD patients is of critical urgency. Human genetic and clinical studies over the past three decades have indicated that abnormal generation or accumulation of amyloid-β (Aβ) peptides is a likely culprit in AD pathogenesis. Aβ is generated from amyloid precursor protein (APP) via proteolytic cleavage by β-site APP cleaving enzyme 1 (BACE1) (memapsin 2, β-secretase, Asp 2 protease) and γ-secretase. Mice deficient in BACE1 show abrogated production of Aβ. Therefore, pharmacological inhibition of BACE1 is being intensively pursued as a therapeutic approach to treat AD patients. Recent setbacks in clinical trials with BACE1 inhibitors have highlighted the critical importance of understanding how to properly inhibit BACE1 to treat AD patients. This review summarizes the recent studies on the role of BACE1 in synaptic functions as well as our views on BACE1 inhibition as an effective AD treatment.
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Affiliation(s)
- Brati Das
- Department of Neuroscience, Room E4032, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA
| | - Riqiang Yan
- Department of Neuroscience, Room E4032, UConn Health, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA.
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35
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Lumsden AL, Rogers JT, Majd S, Newman M, Sutherland GT, Verdile G, Lardelli M. Dysregulation of Neuronal Iron Homeostasis as an Alternative Unifying Effect of Mutations Causing Familial Alzheimer's Disease. Front Neurosci 2018; 12:533. [PMID: 30150923 PMCID: PMC6099262 DOI: 10.3389/fnins.2018.00533] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/16/2018] [Indexed: 12/12/2022] Open
Abstract
The overwhelming majority of dominant mutations causing early onset familial Alzheimer’s disease (EOfAD) occur in only three genes, PSEN1, PSEN2, and APP. An effect-in-common of these mutations is alteration of production of the APP-derived peptide, amyloid β (Aβ). It is this key fact that underlies the authority of the Amyloid Hypothesis that has informed Alzheimer’s disease research for over two decades. Any challenge to this authority must offer an alternative explanation for the relationship between the PSEN genes and APP. In this paper, we explore one possible alternative relationship – the dysregulation of cellular iron homeostasis as a common effect of EOfAD mutations in these genes. This idea is attractive since it provides clear connections between EOfAD mutations and major characteristics of Alzheimer’s disease such as dysfunctional mitochondria, vascular risk factors/hypoxia, energy metabolism, and inflammation. We combine our ideas with observations by others to describe a “Stress Threshold Change of State” model of Alzheimer’s disease that may begin to explain the existence of both EOfAD and late onset sporadic (LOsAD) forms of the disease. Directing research to investigate the role of dysregulation of iron homeostasis in EOfAD may be a profitable way forward in our struggle to understand this form of dementia.
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Affiliation(s)
- Amanda L Lumsden
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Jack T Rogers
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Harvard University, Charlestown, MA, United States
| | - Shohreh Majd
- Neuronal Injury and Repair Laboratory, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Morgan Newman
- Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Greg T Sutherland
- Discipline of Pathology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Giuseppe Verdile
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia
| | - Michael Lardelli
- Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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Czeczor JK, Genders AJ, Aston-Mourney K, Connor T, Hall LG, Hasebe K, Ellis M, De Jong KA, Henstridge DC, Meikle PJ, Febbraio MA, Walder K, McGee SL. APP deficiency results in resistance to obesity but impairs glucose tolerance upon high fat feeding. J Endocrinol 2018; 237:311-322. [PMID: 29674342 DOI: 10.1530/joe-18-0051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 04/19/2018] [Indexed: 12/22/2022]
Abstract
The amyloid precursor protein (APP) generates a number of peptides when processed through different cleavage mechanisms, including the amyloid beta peptide that is implicated in the development of Alzheimer's disease. It is well established that APP via its cleaved peptides regulates aspects of neuronal metabolism. Emerging evidence suggests that amyloidogenic processing of APP can lead to altered systemic metabolism, similar to that observed in metabolic disease states. In the present study, we investigated the effect of APP deficiency on obesity-induced alterations in systemic metabolism. Compared with WT littermates, APP-deficient mice were resistant to diet-induced obesity, which was linked to higher energy expenditure and lipid oxidation throughout the dark phase and was associated with increased spontaneous physical activity. Consistent with this lean phenotype, APP-deficient mice fed a high-fat diet (HFD) had normal insulin tolerance. However, despite normal insulin action, these mice were glucose intolerant, similar to WT mice fed a HFD. This was associated with reduced plasma insulin in the early phase of the glucose tolerance test. Analysis of the pancreas showed that APP was required to maintain normal islet and β-cell mass under high fat feeding conditions. These studies show that, in addition to regulating aspects of neuronal metabolism, APP is an important regulator of whole body energy expenditure and glucose homeostasis under high fat feeding conditions.
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Affiliation(s)
- Juliane K Czeczor
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Amanda J Genders
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Kathryn Aston-Mourney
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Timothy Connor
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Liam G Hall
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Kyoko Hasebe
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Megan Ellis
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Kirstie A De Jong
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | | | - Peter J Meikle
- Baker Heart and Diabetes InstituteMelbourne, Victoria, Australia
| | - Mark A Febbraio
- Division of Diabetes and MetabolismGarvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Ken Walder
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
| | - Sean L McGee
- Metabolic Research UnitSchool of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, Victoria, Australia
- Baker Heart and Diabetes InstituteMelbourne, Victoria, Australia
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37
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Begcevic I, Brinc D, Brown M, Martinez-Morillo E, Goldhardt O, Grimmer T, Magdolen V, Batruch I, Diamandis EP. Brain-related proteins as potential CSF biomarkers of Alzheimer's disease: A targeted mass spectrometry approach. J Proteomics 2018; 182:12-20. [PMID: 29684683 DOI: 10.1016/j.jprot.2018.04.027] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/15/2018] [Accepted: 04/17/2018] [Indexed: 12/30/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, characterized by progressive cognitive decline. The main disease hallmarks include amyloid beta aggregates and neurofibrillary tangles. Brain pathology is reflected in cerebrospinal fluid (CSF); the core biomarkers amyloid beta 1-42, total and phosphorylated tau protein levels are changed, relative to cognitively normal elderly. Still, there is a need for additional biomarkers which could identify disease more accurately and at an earlier stage, predict severity and be used in research settings. Here we evaluated 30 brain-related proteins as candidate biomarkers of AD. Proteins were quantified in CSF samples from cognitively healthy individuals (n = 23) and patients with mild cognitive impairment (MCI) due to AD (n = 20) or dementia due to AD (n = 10) using selected reaction monitoring mass spectrometry assays. APLP1 protein was increased in MCI relative to control (p < 0.001). The best discrimination between MCI vs. controls was observed with a model combining APLP1 and SPP1 proteins (area under the curve, AUC = 0.84). The strongest associations between protein abundance and disease severity were found for APLP1, CNTN2 and SPP1 proteins, which had a significant correlation with MMSE and CDR tests (p < 0.05). This study identifies new proteins with biomarker potential at various stages of AD severity. SIGNIFICANCE The current study evaluated 30 brain-related, highly specific proteins as candidate biomarkers of AD diagnosis. Protein APLP1 showed promise as early AD biomarker; protein panel APLP1 and SPP1 had the best diagnostic potential in discriminating MCI from control group, while proteins APLP1, SPP1 and CNTN2 may be indicators of disease progression, demonstrating weak to moderate correlation with cognitive tests. This study therefore identifies new proteins with biomarker potential at early AD stage. If the performance of proposed biomarkers is further confirmed, these proteins may add value in the clinic or clinical trial settings as diagnostic biomarkers (alone or in combination with the existing biomarkers) of the prodromal AD stage, and in monitoring disease progression.
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Affiliation(s)
- Ilijana Begcevic
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Pathology & Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada
| | - Davor Brinc
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Pathology & Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada; Department of Clinical Biochemistry, University Health Network, Toronto, Canada
| | - Marshall Brown
- Department of Biostatistics, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Eduardo Martinez-Morillo
- Laboratory of Medicine, Department of Clinical Biochemistry, Hospital Universitario Central, Oviedo, Spain
| | - Oliver Goldhardt
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Timo Grimmer
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Viktor Magdolen
- Department of Obstetrics and Gynecology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Ihor Batruch
- Department of Pathology & Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada
| | - Eleftherios P Diamandis
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Pathology & Laboratory Medicine, Mount Sinai Hospital, Toronto, Canada; Department of Clinical Biochemistry, University Health Network, Toronto, Canada.
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38
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Schauenburg L, Liebsch F, Eravci M, Mayer MC, Weise C, Multhaup G. APLP1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Sci Rep 2018; 8:1916. [PMID: 29382944 PMCID: PMC5789831 DOI: 10.1038/s41598-018-19530-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/04/2018] [Indexed: 12/12/2022] Open
Abstract
Regulated intramembrane proteolysis of the amyloid precursor protein (APP) and its homologs, the APP like proteins APLP1 and APLP2, is typically a two-step process, which is initiated by ectodomain-shedding of the substrates by α- or β-secretases. Growing evidence, however, indicates that the cleavage process for APLP1 is different than for APP. Here, we describe that full-length APLP1, but not APP or APLP2, is uniquely cleaved by γ-secretase without previous ectodomain shedding. The new fragment, termed sAPLP1γ, was exclusively associated with APLP1, not APP, APLP2. We provide an exact molecular analysis showing that sAPLP1γ was uniquely generated by γ-secretase from full-length APLP1. Mass spectrometry analysis showed that the sAPLP1γ fragment and the longest Aβ-like peptide share the C-terminus. This novel mechanism of γ-secretase action is consistent with an ϵ-cut based upon the nature of the reaction in APP. We further demonstrate that the APLP1 transmembrane sequence is the critical determinant for γ-shedding and release of full-length APLP1. Moreover, the APLP1 TMS is sufficient to convert larger type-I membrane proteins like APP into direct γ-secretase substrates. Taken together, the direct cleavage of APLP1 is a novel feature of the γ-secretase prompting a re-thinking of γ-secretase activity modulation as a therapeutic strategy for Alzheimer disease.
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Affiliation(s)
- Linda Schauenburg
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Sphingotec Therapeutics GmbH, Neuendorfstr. 15a, 16761, Hennigsdorf, Germany
| | - Filip Liebsch
- Department of Pharmacology & Therapeutics and Integrated Program in Neuroscience, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Murat Eravci
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Magnus C Mayer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Miltenyi Biotec GmbH, Robert-Koch-Strasse 1, 17166, Teterow, Germany
| | - Christoph Weise
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Gerhard Multhaup
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany. .,Department of Pharmacology & Therapeutics and Integrated Program in Neuroscience, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada.
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39
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Kumar DKV, Choi SH, Washicosky KJ, Eimer WA, Tucker S, Ghofrani J, Lefkowitz A, McColl G, Goldstein LE, Tanzi RE, Moir RD. Amyloid-β peptide protects against microbial infection in mouse and worm models of Alzheimer's disease. Sci Transl Med 2017; 8:340ra72. [PMID: 27225182 DOI: 10.1126/scitranslmed.aaf1059] [Citation(s) in RCA: 677] [Impact Index Per Article: 96.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 05/10/2016] [Indexed: 12/19/2022]
Abstract
The amyloid-β peptide (Aβ) is a key protein in Alzheimer's disease (AD) pathology. We previously reported in vitro evidence suggesting that Aβ is an antimicrobial peptide. We present in vivo data showing that Aβ expression protects against fungal and bacterial infections in mouse, nematode, and cell culture models of AD. We show that Aβ oligomerization, a behavior traditionally viewed as intrinsically pathological, may be necessary for the antimicrobial activities of the peptide. Collectively, our data are consistent with a model in which soluble Aβ oligomers first bind to microbial cell wall carbohydrates via a heparin-binding domain. Developing protofibrils inhibited pathogen adhesion to host cells. Propagating β-amyloid fibrils mediate agglutination and eventual entrapment of unatttached microbes. Consistent with our model, Salmonella Typhimurium bacterial infection of the brains of transgenic 5XFAD mice resulted in rapid seeding and accelerated β-amyloid deposition, which closely colocalized with the invading bacteria. Our findings raise the intriguing possibility that β-amyloid may play a protective role in innate immunity and infectious or sterile inflammatory stimuli may drive amyloidosis. These data suggest a dual protective/damaging role for Aβ, as has been described for other antimicrobial peptides.
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Affiliation(s)
- Deepak Kumar Vijaya Kumar
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Se Hoon Choi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Kevin J Washicosky
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - William A Eimer
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Stephanie Tucker
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Jessica Ghofrani
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Aaron Lefkowitz
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Gawain McColl
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Lee E Goldstein
- Department of Psychiatry, Boston University, Boston, MA 02215, USA
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
| | - Robert D Moir
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
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40
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Amyloid precursor protein and amyloid precursor-like protein 2 in cancer. Oncotarget 2017; 7:19430-44. [PMID: 26840089 PMCID: PMC4991393 DOI: 10.18632/oncotarget.7103] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/23/2016] [Indexed: 12/22/2022] Open
Abstract
Amyloid precursor protein (APP) and its family members amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2) are type 1 transmembrane glycoproteins that are highly conserved across species. The transcriptional regulation of APP and APLP2 is similar but not identical, and the cleavage of both proteins is regulated by phosphorylation. APP has been implicated in Alzheimer's disease causation, and in addition to its importance in neurology, APP is deregulated in cancer cells. APLP2 is likewise overexpressed in cancer cells, and APLP2 and APP are linked to increased tumor cell proliferation, migration, and invasion. In this present review, we discuss the unfolding account of these APP family members’ roles in cancer progression and metastasis.
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41
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Dunsing V, Mayer M, Liebsch F, Multhaup G, Chiantia S. Direct evidence of amyloid precursor-like protein 1 trans interactions in cell-cell adhesion platforms investigated via fluorescence fluctuation spectroscopy. Mol Biol Cell 2017; 28:3609-3620. [PMID: 29021345 PMCID: PMC5706989 DOI: 10.1091/mbc.e17-07-0459] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/13/2017] [Accepted: 10/04/2017] [Indexed: 01/25/2023] Open
Abstract
The amyloid precursor–like protein 1 (APLP1) plays a role in synaptic adhesion and synaptogenesis. In this work, we use quantitative fluorescence microscopy to demonstrate the existence of APLP1–APLP1 trans interaction across cell–cell junctions and propose a model explaining the molecular mechanism driving APLP1 multimerization. The amyloid precursor–like protein 1 (APLP1) is a type I transmembrane protein that plays a role in synaptic adhesion and synaptogenesis. Past investigations indicated that APLP1 is involved in the formation of protein–protein complexes that bridge the junctions between neighboring cells. Nevertheless, APLP1–APLP1 trans interactions have never been directly observed in higher eukaryotic cells. Here, we investigated APLP1 interactions and dynamics directly in living human embryonic kidney cells using fluorescence fluctuation spectroscopy techniques, namely cross-correlation scanning fluorescence correlation spectroscopy and number and brightness analysis. Our results show that APLP1 forms homotypic trans complexes at cell–cell contacts. In the presence of zinc ions, the protein forms macroscopic clusters, exhibiting an even higher degree of trans binding and strongly reduced dynamics. Further evidence from giant plasma membrane vesicles suggests that the presence of an intact cortical cytoskeleton is required for zinc-induced cis multimerization. Subsequently, large adhesion platforms bridging interacting cells are formed through APLP1–APLP1 trans interactions. Taken together, our results provide direct evidence that APLP1 functions as a neuronal zinc-dependent adhesion protein and allow a more detailed understanding of the molecular mechanisms driving the formation of APLP1 adhesion platforms.
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Affiliation(s)
- Valentin Dunsing
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Magnus Mayer
- Institute of Chemistry and Biochemistry, Free University of Berlin, 14195 Berlin, Germany
| | - Filip Liebsch
- Department of Pharmacology and Therapeutics/Integrated Program in Neuroscience, McGill University, Montreal, QC H3G 1Y63, Canada
| | - Gerhard Multhaup
- Department of Pharmacology and Therapeutics/Integrated Program in Neuroscience, McGill University, Montreal, QC H3G 1Y63, Canada
| | - Salvatore Chiantia
- Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
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42
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Han K, Müller UC, Hülsmann S. Amyloid-precursor Like Proteins APLP1 and APLP2 Are Dispensable for Normal Development of the Neonatal Respiratory Network. Front Mol Neurosci 2017; 10:189. [PMID: 28690498 PMCID: PMC5479907 DOI: 10.3389/fnmol.2017.00189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/29/2017] [Indexed: 11/13/2022] Open
Abstract
Recent studies using animal models indicated that the members of the amyloid precursor protein (APP) gene family are important for the formation, maintenance, and plasticity of synapses. Despite this, the specific role of the APP homologs APLP1 and APLP2 within the CNS and PNS is still poorly understood. In contrast to the subtle phenotypes of single mutants, double knockout mice (DKO) lacking APP/APLP2 or APLP1/APLP2 die within the first day after birth. Whereas APP/APLP2-DKO mice show severe deficits of neuromuscular morphology and transmission, the underlying cause of lethality of APLP1/APLP2-DKO mice remains unclear. Since expression of both proteins was confirmed by in situ hybridization, we aimed to test the role of APLP1/APLP2 in the formation and maintenance of synapses in the brainstem, and assessed a potential dysfunction of the most vital central neuronal network in APLP1/APLP2-DKO mice by analyzing the respiratory network of the medulla. We performed in vivo unrestrained whole body plethysmography in newborn APLP1/APLP2-DKO mice at postnatal day zero. Additionally, we directly tested the activity of the respiratory network in an acute slice preparation that includes the pre-Bötzinger complex. In both sets of experiments, no significant differences were detected regarding respiratory rate and cycle variability, strongly arguing against central respiratory problems as the primary cause of death of APLP1/APLP2-DKO mice. Thus, we conclude that APLP1 and APLP2 are dispensable for the development of the network and the generation of a normal breathing rhythm.
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Affiliation(s)
- Kang Han
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg UniversityHeidelberg, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg UniversityHeidelberg, Germany
| | - Swen Hülsmann
- Klinik für Anästhesiologie, Universitätsmedizin GöttingenGöttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
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43
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Dysregulation of intracellular trafficking and endosomal sorting in Alzheimer's disease: controversies and unanswered questions. Biochem J 2017; 473:1977-93. [PMID: 27407168 DOI: 10.1042/bcj20160147] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/18/2016] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid plaques in the brain consisting of an aggregated form of amyloid β-peptide (Aβ) derived from sequential amyloidogenic processing of the amyloid precursor protein (APP) by membrane-bound proteases β-site APP-cleaving enzyme 1 (BACE1) and γ-secretase. The initial processing of APP by BACE1 is re-gulated by intracellular sorting events of the enzyme, which is a prime target for therapeutic intervention. GWAS (genome-wide sequencing studies) have identified several AD-susceptibility genes that are associated with the regulation of membrane trafficking, and substantial evidence now indicates that AD is likely to arise from defective membrane trafficking in either or both of the secretory and endocytic pathways. Considerable progress has been made in defining the intracellular trafficking pathways of BACE1 and APP and the sorting signals of these membrane proteins that define their itineraries. In this review we highlight recent advances in understanding the regulation of the intracellular sorting of BACE1 and APP, discuss how dysregulation of these trafficking events may lead to enhanced generation of the neurotoxic Aβ products in AD and highlight the unresolved questions in the field.
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44
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Czeczor JK, McGee SL. Emerging roles for the amyloid precursor protein and derived peptides in the regulation of cellular and systemic metabolism. J Neuroendocrinol 2017; 29. [PMID: 28349564 DOI: 10.1111/jne.12470] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/03/2017] [Accepted: 03/22/2017] [Indexed: 01/01/2023]
Abstract
The amyloid precursor protein (APP) is a transmembrane protein that can be cleaved by proteases through two different pathways to yield a number of small peptides, each with distinct physiological properties and functions. It has been extensively studied in the context of Alzheimer's disease, with the APP-derived amyloid β (Aβ) peptide being a major constituent of the amyloid plaques observed in this disease. It has been known for some time that APP can regulate neuronal metabolism; however, the present review examines the evidence indicating that APP and its peptides can also regulate key metabolic processes such as insulin action, lipid synthesis and storage and mitochondrial function in peripheral tissues. This review presents the hypothesis that amyloidogenic processing of APP in peripheral tissues plays a key role in the response to nutrient excess and that this could contribute to the pathogenesis of metabolic diseases such as obesity and type 2 diabetes (T2D).
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Affiliation(s)
- J K Czeczor
- Metabolic Research Unit, Metabolic Reprogramming Laboratory, School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, VIC, Australia
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine University, Düsseldorf, Germany
- German Center of Diabetes Research, München-Neuherberg, Germany
| | - S L McGee
- Metabolic Research Unit, Metabolic Reprogramming Laboratory, School of Medicine and Centre for Molecular and Medical Research, Deakin University, Geelong, VIC, Australia
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45
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APLP1 Is a Synaptic Cell Adhesion Molecule, Supporting Maintenance of Dendritic Spines and Basal Synaptic Transmission. J Neurosci 2017; 37:5345-5365. [PMID: 28450540 DOI: 10.1523/jneurosci.1875-16.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 02/22/2017] [Accepted: 03/24/2017] [Indexed: 12/19/2022] Open
Abstract
The amyloid precursor protein (APP), a key player in Alzheimer's disease, belongs to the family of synaptic adhesion molecules (SAMs) due to its impact on synapse formation and synaptic plasticity. These functions are mediated by both the secreted APP ectodomain that acts as a neurotrophic factor and full-length APP forming trans-cellular dimers. Two homologs of APP exist in mammals: the APP like proteins APLP1 and APLP2, exhibiting functions that partly overlap with those of APP. Here we tested whether APLP1 and APLP2 also show features of SAMs. We found that all three family members were upregulated during postnatal development coinciding with synaptogenesis. We observed presynaptic and postsynaptic localization of all APP family members and could show that heterologous expression of APLP1 or APLP2 in non-neuronal cells induces presynaptic differentiation in contacting axons of cocultured neurons, similar to APP and other SAMs. Moreover, APP/APLPs all bind to synaptic-signaling molecules, such as MINT/X11. Furthermore, we report that aged APLP1 knock-out mice show impaired basal transmission and a reduced mEPSC frequency, likely resulting from reduced spine density. This demonstrates an essential nonredundant function of APLP1 at the synapse. Compared to APP, APLP1 exhibits increased trans-cellular binding and elevated cell-surface levels due to reduced endocytosis. In conclusion, our results establish that APLPs show typical features of SAMs and indicate that increased surface expression, as observed for APLP1, is essential for proper synapse formation in vitro and synapse maintenance in vivoSIGNIFICANCE STATEMENT According to the amyloid-cascade hypothesis, Alzheimer's disease is caused by the accumulation of Aβ peptides derived from sequential cleavage of the amyloid precursor protein (APP) by β-site APP cleaving enzyme 1 (BACE1) and γ-secretase. Here we show that all mammalian APP family members (APP, APLP1, and APLP2) exhibit synaptogenic activity, involving trans-synaptic dimerization, similar to other synaptic cell adhesion molecules, such as Neuroligin/Neurexin. Importantly, our study revealed that the loss of APLP1, which is one of the major substrates of BACE1, causes reduced spine density in aged mice. Because some therapeutic interventions target APP processing (e.g., BACE inhibitors), those strategies may alter APP/APLP physiological function. This should be taken into account for the development of pharmaceutical treatments of Alzheimer's disease.
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46
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Not just amyloid: physiological functions of the amyloid precursor protein family. Nat Rev Neurosci 2017; 18:281-298. [PMID: 28360418 DOI: 10.1038/nrn.2017.29] [Citation(s) in RCA: 387] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyloid precursor protein (APP) gives rise to the amyloid-β peptide and thus has a key role in the pathogenesis of Alzheimer disease. By contrast, the physiological functions of APP and the closely related APP-like proteins (APLPs) remain less well understood. Studying these physiological functions has been challenging and has required a careful long-term strategy, including the analysis of different App-knockout and Aplp-knockout mice. In this Review, we summarize these findings, focusing on the in vivo roles of APP family members and their processing products for CNS development, synapse formation and function, brain injury and neuroprotection, as well as ageing. In addition, we discuss the implications of APP physiology for therapeutic approaches.
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47
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Weingarten J, Weingarten M, Wegner M, Volknandt W. APP-A Novel Player within the Presynaptic Active Zone Proteome. Front Mol Neurosci 2017; 10:43. [PMID: 28265241 PMCID: PMC5316543 DOI: 10.3389/fnmol.2017.00043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/07/2017] [Indexed: 11/13/2022] Open
Abstract
The amyloid precursor protein (APP) was discovered in the 1980s as the precursor protein of the amyloid A4 peptide. The amyloid A4 peptide, also known as A-beta (Aβ), is the main constituent of senile plaques implicated in Alzheimer's disease (AD). In association with the amyloid deposits, increasing impairments in learning and memory as well as the degeneration of neurons especially in the hippocampus formation are hallmarks of the pathogenesis of AD. Within the last decades much effort has been expended into understanding the pathogenesis of AD. However, little is known about the physiological role of APP within the central nervous system (CNS). Allocating APP to the proteome of the highly dynamic presynaptic active zone (PAZ) identified APP as a novel player within this neuronal communication and signaling network. The analysis of the hippocampal PAZ proteome derived from APP-mutant mice demonstrates that APP is tightly embedded in the underlying protein network. Strikingly, APP deletion accounts for major dysregulation within the PAZ proteome network. Ca2+-homeostasis, neurotransmitter release and mitochondrial function are affected and resemble the outcome during the pathogenesis of AD. The observed changes in protein abundance that occur in the absence of APP as well as in AD suggest that APP is a structural and functional regulator within the hippocampal PAZ proteome. Within this review article, we intend to introduce APP as an important player within the hippocampal PAZ proteome and to outline the impact of APP deletion on individual PAZ proteome subcommunities.
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Affiliation(s)
- Jens Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
| | - Melanie Weingarten
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
| | - Martin Wegner
- Department of Molecular Bioinformatics, Goethe University Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute for Cell Biology and Neuroscience, Biologicum and BMLS, Goethe University Frankfurt am Main, Germany
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48
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Ludewig S, Korte M. Novel Insights into the Physiological Function of the APP (Gene) Family and Its Proteolytic Fragments in Synaptic Plasticity. Front Mol Neurosci 2017; 9:161. [PMID: 28163673 PMCID: PMC5247455 DOI: 10.3389/fnmol.2016.00161] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/14/2016] [Indexed: 12/31/2022] Open
Abstract
The amyloid precursor protein (APP) is well known to be involved in the pathophysiology of Alzheimer's disease (AD) via its cleavage product amyloid ß (Aß). However, the physiological role of APP, its various proteolytic products and the amyloid precursor-like proteins 1 and 2 (APLP1/2) are still not fully clarified. Interestingly, it has been shown that learning and memory processes represented by functional and structural changes at synapses are altered in different APP and APLP1/2 mouse mutants. In addition, APP and its fragments are implicated in regulating synaptic strength further reinforcing their modulatory role at the synapse. While APLP2 and APP are functionally redundant, the exclusively CNS expressed APLP1, might have individual roles within the synaptic network. The proteolytic product of non-amyloidogenic APP processing, APPsα, emerged as a neurotrophic peptide that facilitates long-term potentiation (LTP) and restores impairments occurring with age. Interestingly, the newly discovered η-secretase cleavage product, An-α acts in the opposite direction, namely decreasing LTP. In this review we summarize recent findings with emphasis on the physiological role of the APP gene family and its proteolytic products on synaptic function and plasticity, especially during processes of hippocampal LTP. Therefore, we focus on literature that provide electrophysiological data by using different mutant mouse strains either lacking full-length or parts of the APP proteins or that utilized secretase inhibitors as well as secreted APP fragments.
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Affiliation(s)
- Susann Ludewig
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig Braunschweig, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU BraunschweigBraunschweig, Germany; Helmholtz Centre for Infection Research, AG NINDBraunschweig, Germany
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49
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Veenstra TD. Neuroproteomic tools for battling Alzheimer's disease. Proteomics 2016; 16:2847-2853. [DOI: 10.1002/pmic.201600211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 08/25/2016] [Accepted: 09/13/2016] [Indexed: 01/09/2023]
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50
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Paschkowsky S, Hamzé M, Oestereich F, Munter LM. Alternative Processing of the Amyloid Precursor Protein Family by Rhomboid Protease RHBDL4. J Biol Chem 2016; 291:21903-21912. [PMID: 27563067 DOI: 10.1074/jbc.m116.753582] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Indexed: 12/13/2022] Open
Abstract
The amyloid precursor protein (APP) is an ubiquitously expressed cell surface protein and a key molecule in the etiology of Alzheimer disease. Amyloidogenic processing of APP through secretases leads to the generation of toxic amyloid β (Aβ) peptides, which are regarded as the molecular cause of the disease. We report here an alternative processing pathway of APP through the mammalian intramembrane rhomboid protease RHBDL4. RHBDL4 efficiently cleaves APP inside the cell, thus bypassing APP from amyloidogenic processing, leading to reduced Aβ levels. RHBDL4 cleaves APP multiple times in the ectodomain, resulting in several N- and C-terminal fragments that are not further degraded by classical APP secretases. Knockdown of endogenous RHBDL4 results in decreased levels of C-terminal fragments derived from endogenous APP. Similarly, we found the APP family members APLP1 and APLP2 to be substrates of RHBDL4. We conclude that RHBDL4-mediated APP processing provides insight into APP and rhomboid physiology and qualifies for further investigations to elaborate its impact on Alzheimer disease pathology.
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Affiliation(s)
| | - Mehdi Hamzé
- From the Department of Pharmacology and Therapeutics and
| | - Felix Oestereich
- From the Department of Pharmacology and Therapeutics and Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3G 0B1, Canada
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