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Hok‐A‐Hin YS, Bolsewig K, Ruiters DN, Lleó A, Alcolea D, Lemstra AW, van der Flier WM, Teunissen CE, del Campo M. Thimet oligopeptidase as a potential CSF biomarker for Alzheimer's disease: A cross-platform validation study. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2023; 15:e12456. [PMID: 37502019 PMCID: PMC10369371 DOI: 10.1002/dad2.12456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/29/2023]
Abstract
INTRODUCTION Our previous antibody-based cerebrospinal fluid (CSF) proteomics study showed that Thimet oligopeptidase (THOP1), an amyloid beta (Aβ) neuropeptidase, was increased in mild cognitive impairment with amyloid pathology (MCI-Aβ+) and Alzheimer's disease (AD) dementia compared with controls and dementia with Lewy bodies (DLB), highlighting the potential of CSF THOP1 as an early specific biomarker for AD. We aimed to develop THOP1 immunoassays for large-scale analysis and validate our proteomics findings in two independent cohorts. METHODS We developed in-house CSF THOP1 immunoassays on automated Ella and Simoa platforms. The performance of the different assays were compared using Passing-Bablok regression analysis in a subset of CSF samples from the discovery cohort (n = 72). Clinical validation was performed in two independent cohorts (cohort 1: n = 200; cohort 2: n = 165) using the Ella platform. RESULTS THOP1 concentrations moderately correlated between proteomics analysis and our novel assays (Rho > 0.580). In both validation cohorts, CSF THOP1 was increased in MCI-Aβ+ (>1.3-fold) and AD (>1.2-fold) compared with controls; and between MCI-Aβ+ and DLB (>1.2-fold). Higher THOP1 concentrations were detected in AD compared with DLB only when both cohorts were analyzed together. In both cohorts, THOP1 correlated with CSF total tau (t-tau), phosphorylated tau (p-tau), and Aβ40 (Rho > 0.540) but not Aβ42. DISCUSSION Validation of our proteomics findings underpins the potential of CSF THOP1 as an early specific biomarker associated with AD pathology. The use of antibody-based platforms in both the discovery and validation phases facilitated the translation of proteomics findings, providing an additional workflow that may accelerate the development of biofluid-based biomarkers.
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Affiliation(s)
- Yanaika S. Hok‐A‐Hin
- Neurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam NeuroscienceVU University Medical Center, Amsterdam UMCAmsterdamThe Netherlands
| | - Katharina Bolsewig
- Neurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam NeuroscienceVU University Medical Center, Amsterdam UMCAmsterdamThe Netherlands
| | - Daimy N. Ruiters
- Neurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam NeuroscienceVU University Medical Center, Amsterdam UMCAmsterdamThe Netherlands
| | - Alberto Lleó
- Department of Neurology, Institut d'Investigacions Biomèdiques Sant Pau ‐ Hospital de Sant PauUniversitat Autònoma de Barcelona, Hospital de la Santa Creu i Sant PauBarcelonaSpain
| | - Daniel Alcolea
- Department of Neurology, Institut d'Investigacions Biomèdiques Sant Pau ‐ Hospital de Sant PauUniversitat Autònoma de Barcelona, Hospital de la Santa Creu i Sant PauBarcelonaSpain
| | - Afina W. Lemstra
- Alzheimer Center Amsterdam, Department of NeurologyAmsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMCAmsterdamThe Netherlands
| | - Wiesje M. van der Flier
- Alzheimer Center Amsterdam, Department of NeurologyAmsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMCAmsterdamThe Netherlands
- Department of Epidemiology and Data ScienceVU University Medical CentersAmsterdamThe Netherlands
| | - Charlotte E. Teunissen
- Neurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam NeuroscienceVU University Medical Center, Amsterdam UMCAmsterdamThe Netherlands
| | - Marta del Campo
- Neurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam NeuroscienceVU University Medical Center, Amsterdam UMCAmsterdamThe Netherlands
- Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de FarmaciaUniversidad San Pablo‐CEU, CEU UniversitiesMadridSpain
- Bareclonaβeta Brain Research Center (BBRC)Pasqual Maragall FoundationBarcelonaSpain
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Abstract
Peptidases generate bioactive peptides that can regulate cell signaling and mediate intercellular communication. While the processing of peptide precursors is initiated intracellularly, some modifications by peptidases may be conducted extracellularly. Thimet oligopeptidase (TOP) is a peptidase that processes neuroendocrine peptides with roles in mood, metabolism, and immune responses, among other functions. TOP also hydrolyzes angiotensin I to angiotensin 1–7, which may be involved in the pathophysiology of COVID-19 infection. Although TOP is primarily cytosolic, it can also be associated with the cell plasma membrane or secreted to the extracellular space. Recent work indicates that membrane-associated TOP can be released with extracellular vesicles (EVs) to the extracellular space. Here we briefly summarize the enzyme’s classical function in extracellular processing of neuroendocrine peptides, as well as its more recently understood role in intracellular processing of various peptides that impact human diseases. Finally, we discuss new findings of EV-associated TOP in the extracellular space.
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Pedrero-Prieto CM, Frontiñán-Rubio J, Alcaín FJ, Durán-Prado M, Peinado JR, Rabanal-Ruiz Y. Biological Significance of the Protein Changes Occurring in the Cerebrospinal Fluid of Alzheimer's Disease Patients: Getting Clues from Proteomic Studies. Diagnostics (Basel) 2021; 11:1655. [PMID: 34573996 PMCID: PMC8467255 DOI: 10.3390/diagnostics11091655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/18/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022] Open
Abstract
The fact that cerebrospinal fluid (CSF) deeply irrigates the brain together with the relative simplicity of sample extraction from patients make this biological fluid the best target for biomarker discovery in neurodegenerative diseases. During the last decade, biomarker discovery has been especially fruitful for the identification new proteins that appear in the CSF of Alzheimer's disease (AD) patients together with amyloid-β (Aβ42), total tau (T-tau), and phosphorylated tau (P-tau). Thus, several proteins have been already stablished as important biomarkers, due to an increase (i.e., CHI3L1) or a decrease (i.e., VGF) in AD patients' CSF. Notwithstanding this, only a deep analysis of a database generated with all the changes observed in CSF across multiple proteomic studies, and especially those using state-of-the-art methodologies, may expose those components or metabolic pathways disrupted at different levels in AD. Deep comparative analysis of all the up- and down-regulated proteins across these studies revealed that 66% of the most consistent protein changes in CSF correspond to intracellular proteins. Interestingly, processes such as those associated to glucose metabolism or RXR signaling appeared inversely represented in CSF from AD patients in a significant manner. Herein, we discuss whether certain cellular processes constitute accurate indicators of AD progression by examining CSF. Furthermore, we uncover new CSF AD markers, such as ITAM, PTPRZ or CXL16, identified by this study.
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Affiliation(s)
- Cristina M. Pedrero-Prieto
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha (UCLM), 13005 Ciudad Real, Spain
| | - Javier Frontiñán-Rubio
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Francisco J. Alcaín
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Mario Durán-Prado
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Juan R. Peinado
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Yoana Rabanal-Ruiz
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
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Ubina T, Magallanes M, Srivastava S, Warden CD, Yee JK, Salvaterra PM. A Human Embryonic Stem Cell Model of Aβ-Dependent Chronic Progressive Neurodegeneration. Front Neurosci 2019; 13:1007. [PMID: 31616241 PMCID: PMC6763609 DOI: 10.3389/fnins.2019.01007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/05/2019] [Indexed: 11/13/2022] Open
Abstract
We describe the construction and phenotypic analysis of a human embryonic stem cell model of progressive Aβ-dependent neurodegeneration (ND) with potential relevance to Alzheimer’s disease (AD). We modified one allele of the normal APP locus to directly express a secretory form of Aβ40 or Aβ42, enabling expression from this edited allele to bypass the normal amyloidogenic APP processing pathway. Following neuronal differentiation, edited cell lines specifically accumulate intracellular aggregated/oligomeric Aβ, exhibit a synaptic deficit, and have an abnormal accumulation of endolysosomal vesicles. Edited cultures progress to a stage of overt ND. All phenotypes appear at earlier culture times for Aβ42 relative to Aβ40. Whole transcriptome RNA-Seq analysis identified 23 up and 70 down regulated genes (differentially expressed genes) with similar directional fold change but larger absolute values in the Aβ42 samples suggesting common underlying pathogenic mechanisms. Pathway/annotation analysis suggested that down regulation of extracellular matrix and cilia functions is significantly overrepresented. This cellular model could be useful for uncovering mechanisms directly linking Aβ to neuronal death and as a tool to screen for new therapeutic agents that slow or prevent human ND.
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Affiliation(s)
- Teresa Ubina
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States.,Department of Biology, California State University, San Bernardino, San Bernardino, CA, United States
| | - Martha Magallanes
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Saumya Srivastava
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Charles D Warden
- Integrative Genomics Core, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Jiing-Kuan Yee
- Department of Diabetes, Beckman Research Institute - City of Hope, Duarte, CA, United States.,Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute - City of Hope, Duarte, CA, United States
| | - Paul M Salvaterra
- Department of Developmental and Stem Cell Biology, Beckman Research Institute - City of Hope, Duarte, CA, United States.,Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute - City of Hope, Duarte, CA, United States
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Icimoto MY, Ferreira JC, Yokomizo CH, Bim LV, Marem A, Gilio JM, Oliveira V, Nantes IL. Redox modulation of thimet oligopeptidase activity by hydrogen peroxide. FEBS Open Bio 2017; 7:1037-1050. [PMID: 28680816 PMCID: PMC5494303 DOI: 10.1002/2211-5463.12245] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 11/09/2022] Open
Abstract
Thimet oligopeptidase (EC 3.4.24.15, TOP) is a cytosolic mammalian zinc protease that can process a diversity of bioactive peptides. TOP has been pointed out as one of the main postproteasomal enzymes that process peptide antigens in the MHC class I presentation route. In the present study, we describe a fine regulation of TOP activity by hydrogen peroxide (H2O2). Cells from a human embryonic kidney cell line (HEK293) underwent an ischemia/reoxygenation-like condition known to increase H2O2 production. Immediately after reoxygenation, HEK293 cells exhibited a 32% increase in TOP activity, but no TOP activity was observed 2 h after reoxygenation. In another model, recombinant rat TOP (rTOP) was challenged by H2O2 produced by rat liver mitoplasts (RLMt) alone, and in combination with antimycin A, succinate, and antimycin A plus succinate. In these conditions, rTOP activity increased 17, 30, 32 and 38%, respectively. Determination of H2O2 concentration generated in reoxygenated cells and mitoplasts suggested a possible modulation of rTOP activity dependent on the concentration of H2O2. The measure of pure rTOP activity as a function of H2O2 concentration corroborated this hypothesis. The data fitted to an asymmetrical bell-shaped curve in which the optimal activating H2O2 concentration was 1.2 nM, and the maximal inhibition (75% about the control) was 1 μm. Contrary to the oxidation produced by aging associated with enzyme oligomerization and inhibition, H2O2 oxidation produced sulfenic acid and maintained rTOP in the monomeric form. Consistent with the involvement of rTOP in a signaling redox cascade, the H2O2-oxidized rTOP reacted with dimeric thioredoxin-1 (TRx-1) and remained covalently bound to one subunit of TRx-1.
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Affiliation(s)
| | - Juliana C Ferreira
- Laboratório de Nanoestruturas para Biologia e Materiais Avançados Centro de Ciências Naturais e Humanas Universidade Federal do ABC Santo André Brazil.,Present address: Structural Biology and Biophysical Chemistry Lab New York University Abu Dhabi Saadiyat Marina District, Abu Dhabi United Arab Emirates
| | - César H Yokomizo
- Laboratório de Nanoestruturas para Biologia e Materiais Avançados Centro de Ciências Naturais e Humanas Universidade Federal do ABC Santo André Brazil
| | - Larissa V Bim
- Departamento de Biofísica Universidade Federal de São Paulo Brazil
| | - Alyne Marem
- Departamento de Biofísica Universidade Federal de São Paulo Brazil
| | - Joyce M Gilio
- Departamento de Biofísica Universidade Federal de São Paulo Brazil.,Present address: Departamento de Neurologia Centro de Degeneração Universidade de São Paulo - Escola de Medicina São Paulo SP Brazil
| | - Vitor Oliveira
- Departamento de Biofísica Universidade Federal de São Paulo Brazil
| | - Iseli L Nantes
- Laboratório de Nanoestruturas para Biologia e Materiais Avançados Centro de Ciências Naturais e Humanas Universidade Federal do ABC Santo André Brazil
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Philibert KD, Marr RA, Norstrom EM, Glucksman MJ. Identification and characterization of Aβ peptide interactors in Alzheimer's disease by structural approaches. Front Aging Neurosci 2014; 6:265. [PMID: 25346686 PMCID: PMC4191344 DOI: 10.3389/fnagi.2014.00265] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/12/2014] [Indexed: 01/11/2023] Open
Abstract
Currently, there are very limited pharmaceutical interventions for Alzheimer's disease (AD) to alleviate the amyloid burden implicated in the pathophysiology of the disease. Alzheimer's disease is characterized immunohistologically by the accumulation of senile plaques in the brain with afflicted patients progressively losing short-term memory and, ultimately, cognition. Although significant improvements in clinical diagnosis and care for AD patients have been made, effective treatments for this devastating disease remain elusive. A key component of the amyloid burden of AD comes from accumulation of the amyloid-beta (Aβ) peptide which comes from processing of the amyloid precursor protein (APP) by enzymes termed secretases, leading to production of these toxic Aβ peptides of 40-42 amino acids. New therapeutic approaches for reducing Aβ are warranted after the most logical avenues of inhibiting secretase activity appear less than optimal in ameliorating the progression of AD.Novel therapeutics may be gleaned from proteomics biomarker initiatives to yield detailed molecular interactions of enzymes and their potential substrates. Explicating the APPome by deciphering protein complexes forming in cells is a complementary approach to unveil novel molecular interactions with the amyloidogenic peptide precursor to both understand the biology and develop potential upstream drug targets. Utilizing these strategies we have identified EC 3.4.24.15 (EP24.15), a zinc metalloprotease related to neprilysin (NEP), with the ability to catabolize Aβ 1-42 by examining first potential in silico docking and then verification by mass spectrometry. In addition, a hormone carrier protein, transthyreitin (TTR), was identified and with its abundance in cerebrospinal fluid (CSF), found to clear Aβ by inhibiting formation of oligomeric forms of Aβ peptide. The confluence of complementary strategies may allow new therapeutic avenues as well as biomarkers for AD that will aid in diagnosis, prognosis and treatment.
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Affiliation(s)
- Keith D Philibert
- Department of Biochemistry and Molecular Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science North Chicago, IL, USA
| | - Robert A Marr
- Department of Neuroscience, Chicago Medical School, Rosalind Franklin University of Medicine and Science North Chicago, IL, USA
| | - Eric M Norstrom
- Department of Biological Sciences, DePaul University Chicago, IL, USA
| | - Marc J Glucksman
- Department of Biochemistry and Molecular Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science North Chicago, IL, USA
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Simões PSR, Visniauskas B, Perosa SR, Yacubian EMT, Centeno R, Canzian M, Lopes-Cendes I, Maurer Morelli CV, Carrete H, Cavalheiro EA, Tufik S, Chagas JR, Naffah Mazzacoratti MDG. Expression and activity of thimet oligopeptidase (TOP) are modified in the hippocampus of subjects with temporal lobe epilepsy (TLE). Epilepsia 2014; 55:754-762. [DOI: 10.1111/epi.12606] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2014] [Indexed: 01/26/2023]
Affiliation(s)
| | - Bruna Visniauskas
- Psychobiology Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
| | - Sandra Regina Perosa
- Neurology/Neurosurgery Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
| | | | - Ricardo Centeno
- Neurology/Neurosurgery Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
| | - Mauro Canzian
- Pathology Department, Heart Institute-Medicine School University of São Paulo; (INCOR-FMUSP); São Paulo Brazil
| | - Iscia Lopes-Cendes
- Department of Medical Genetics; University of Campinas (UNICAMP); Campinas Brazil
| | | | - Henrique Carrete
- Image and Diagnostic Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
| | - Esper Abrão Cavalheiro
- Neurology/Neurosurgery Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
| | - Sergio Tufik
- Psychobiology Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
| | - Jair Ribeiro Chagas
- Psychobiology Department; Federal University of São Paulo (UNIFESP); São Paulo Brazil
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Mulder SD, Nielsen HM, Blankenstein MA, Eikelenboom P, Veerhuis R. Apolipoproteins E and J interfere with amyloid-beta uptake by primary human astrocytes and microglia in vitro. Glia 2014; 62:493-503. [PMID: 24446231 DOI: 10.1002/glia.22619] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 11/30/2013] [Accepted: 12/06/2013] [Indexed: 12/12/2022]
Abstract
Defective clearance of the amyloid-β peptide (Aβ) from the brain is considered a strong promoter in Alzheimer's disease (AD) pathogenesis. Astrocytes and microglia are important mediators of Aβ clearance and Aβ aggregation state and the presence of amyloid associated proteins (AAPs), such as Apolipoproteins E and J (ApoE and ApoJ), may influence Aβ clearance by these cells. Here we set out to investigate whether astrocytes and microglia differ in uptake efficiency of Aβ oligomers (Aβoligo ) and Aβ fibrils (Aβfib ), and whether the Aβ aggregation state and/or presence of AAPs affect Aβ uptake in these cells in vitro. Adult human primary microglia and astrocytes, isolated from short delay post-mortem brain tissue, were exposed to either Aβoligo or Aβfib alone or combined with a panel of certain AAPs whereafter Aβ-positive cells were quantified using flow cytometry. Upon exposure to Aβ combined with ApoE, ApoJ, α1-antichymotrypsin (ACT) and a combination of serum amyloid P and complement C1q (SAP-C1q), a clear reduction in astrocytic but not microglial Aβoligo uptake, was observed. In contrast, Aβfib uptake was strongly reduced in the presence of AAPs in microglia, but not in astrocytes. These data provide the first evidence of distinct roles of microglia and astrocytes in Aβ clearance. More importantly we show that Aβ clearance by glial cells is negatively affected by AAPs like ApoE and ApoJ. Thus, targeting the association of Aβ with AAPs, such as ApoE and ApoJ, could serve as a therapeutic strategy to increase Aβ clearance by glial cells.
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Affiliation(s)
- Sandra D Mulder
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands; Alzheimer Center, VU University Medical Center, Amsterdam, The Netherlands
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Ferreira JC, Icimoto MY, Marcondes MF, Oliveira V, Nascimento OR, Nantes IL. Recycling of the high valence States of heme proteins by cysteine residues of THIMET-oligopeptidase. PLoS One 2013; 8:e79102. [PMID: 24223886 PMCID: PMC3815109 DOI: 10.1371/journal.pone.0079102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/17/2013] [Indexed: 11/19/2022] Open
Abstract
The peptidolytic enzyme THIMET-oligopeptidase (TOP) is able to act as a reducing agent in the peroxidase cycle of myoglobin (Mb) and horseradish peroxidase (HRP). The TOP-promoted recycling of the high valence states of the peroxidases to the respective resting form was accompanied by a significant decrease in the thiol content of the peptidolytic enzyme. EPR (electron paramagnetic resonance) analysis using DBNBS spin trapping revealed that TOP also prevented the formation of tryptophanyl radical in Mb challenged by H2O2. The oxidation of TOP thiol groups by peroxidases did not promote the inactivating oligomerization observed in the oxidation promoted by the enzyme aging. These findings are discussed towards a possible occurrence of these reactions in cells.
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Affiliation(s)
- Juliana C. Ferreira
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brasil
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo Andre, SP, Brasil
| | - Marcelo Y. Icimoto
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - Marcelo F. Marcondes
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - Vitor Oliveira
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - Otaciro R. Nascimento
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brasil
| | - Iseli L. Nantes
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo Andre, SP, Brasil
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Chen S, Ge X, Chen Y, Lv N, Liu Z, Yuan W. Advances with RNA interference in Alzheimer's disease research. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:117-25. [PMID: 23459401 PMCID: PMC3582316 DOI: 10.2147/dddt.s40229] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized clinically by memory and cognitive dysfunction. Unfortunately, there is no effective therapeutic method for AD treatment or ways to halt disease progression. Many mechanisms are involved in the disease, including genes mutation and protein dysfunction. RNA interference (RNAi) technology may potentially be able to control AD. It can inhibit the protein expression of specific genes by activating a sequence-specific RNA degradation process. This is a powerful tool with which to study gene function, investigate the mechanism of the disease, and validate drug targets. In this review, we highlight the advances in RNAi technology in the investigation and treatment of AD.
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Affiliation(s)
- Shun Chen
- Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai Jiaotong University, Shanghai
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Bang Y, Lim J, Kim SS, Jeong HM, Jung KK, Kang IH, Lee KY, Choi HJ. Aroclor1254 interferes with estrogen receptor-mediated neuroprotection against beta-amyloid toxicity in cholinergic SN56 cells. Neurochem Int 2011; 59:582-90. [DOI: 10.1016/j.neuint.2011.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 04/01/2011] [Accepted: 04/04/2011] [Indexed: 12/11/2022]
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Sigman J, Patwa T, Tablante A, Joseph C, Glucksman M, Wolfson A. Flexibility in substrate recognition by thimet oligopeptidase as revealed by denaturation studies. Biochem J 2009; 388:255-61. [PMID: 15647004 PMCID: PMC1186714 DOI: 10.1042/bj20041481] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Thimet oligopeptidase (TOP) is a soluble metalloendopeptidase belonging to a family of enzymes including neurolysin and neprilysin that utilize the HEXXH metal-binding motif. TOP is widely distributed among cell types and is able to cleave a number of structurally unrelated peptides. A recent focus of interest has been on structure-function relationships in substrate selectivity by TOP. The enzyme's structural fold comprises two domains that are linked at the bottom of a deep substrate-binding cleft via several flexible loop structures. In the present study, fluorescence spectroscopy has been used to probe structural changes in TOP induced by the chemical denaturant urea. Fluorescence emission, anisotropy and collisional quenching data support a two-step unfolding process for the enzyme in which complete loss of the tertiary structure occurs in the second step. Complete loss of activity and loss of catalytic Zn(II) from the active site, monitored by absorption changes of the metal chelator 4-(2-pyridylazo)-resorcinol, are also connected with the second step. In contrast, the first unfolding event, which is linked to changes in the non-catalytic domain, leads to a sharp increase in kcat towards a 9-residue substrate and a sharp decrease in kcat for a 5-residue substrate. Thus a conformational change in TOP has been directly correlated with a change in substrate selectivity. These results provide insight into how the enzyme can process the range of structurally unrelated peptides necessary for its many physiological roles.
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Affiliation(s)
- Jeffrey A. Sigman
- *Chemistry Department, Saint Mary's College of California, 1928 St. Mary's Road, Moraga, CA 94556, U.S.A
| | - Tasneem H. Patwa
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
| | - Ana V. Tablante
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
| | - Calleen D. Joseph
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
| | - Marc J. Glucksman
- ‡Midwest Proteome Center and Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, N. Chicago, IL 60064, U.S.A
| | - Adele J. Wolfson
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
- To whom correspondence should be addressed (email )
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14
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Pollio G, Hoozemans JJM, Andersen CA, Roncarati R, Rosi MC, van Haastert ES, Seredenina T, Diamanti D, Gotta S, Fiorentini A, Magnoni L, Raggiaschi R, Rozemuller AJM, Casamenti F, Caricasole A, Terstappen GC. Increased expression of the oligopeptidase THOP1 is a neuroprotective response to Abeta toxicity. Neurobiol Dis 2008; 31:145-58. [PMID: 18571100 DOI: 10.1016/j.nbd.2008.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/03/2008] [Accepted: 04/17/2008] [Indexed: 01/18/2023] Open
Abstract
In a comprehensive proteomics study aiming at the identification of proteins associated with amyloid-beta (Abeta)-mediated toxicity in cultured cortical neurons, we have identified Thimet oligopeptidase (THOP1). Functional modulation of THOP1 levels in primary cortical neurons demonstrated that its overexpression was neuroprotective against Abeta toxicity, while RNAi knockdown made neurons more vulnerable to amyloid peptide. In the TgCRND8 transgenic mouse model of amyloid plaque deposition, an age-dependent increase of THOP1 expression was found in brain tissue, where it co-localized with Abeta plaques. In accordance with these findings, THOP1 expression was significantly increased in human AD brain tissue as compared to non-demented controls. These results provide compelling evidence for a neuroprotective role of THOP1 against toxic effects of Abeta in the early stages of AD pathology, and suggest that the observed increase in THOP1 expression might be part of a compensatory defense mechanism of the brain against an increased Abeta load.
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Affiliation(s)
- Giuseppe Pollio
- Siena Biotech SpA, Discovery Research, Via Fiorentina 1, 53100 Siena, Italy
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15
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Lim EJ, Sampath S, Coll-Rodriguez J, Schmidt J, Ray K, Rodgers DW. Swapping the Substrate Specificities of the Neuropeptidases Neurolysin and Thimet Oligopeptidase. J Biol Chem 2007; 282:9722-9732. [PMID: 17251185 DOI: 10.1074/jbc.m609897200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thimet oligopeptidase (EC 3.4.24.15) and neurolysin (EC 3.4.24.16) are closely related zinc-dependent metallopeptidases that metabolize small bioactive peptides. They cleave many substrates at the same sites, but they recognize different positions on others, including neurotensin, a 13-residue peptide involved in modulation of dopaminergic circuits, pain perception, and thermoregulation. On the basis of crystal structures and previous mapping studies, four sites (Glu-469/Arg-470, Met-490/Arg-491, His-495/Asn-496, and Arg-498/Thr-499; thimet oligopeptidase residues listed first) in their substrate-binding channels appear positioned to account for differences in specificity. Thimet oligopeptidase mutated so that neurolysin residues are at all four positions cleaves neurotensin at the neurolysin site, and the reverse mutations in neurolysin switch hydrolysis to the thimet oligopeptidase site. Using a series of constructs mutated at just three of the sites, it was determined that mutations at only two (Glu-469/Arg-470 and Arg-498/Thr-499) are required to swap specificity, a result that was confirmed by testing the two-mutant constructs. If only either one of the two sites is mutated in thimet oligopeptidase, then the enzyme cleaves almost equally at the two hydrolysis positions. Crystal structures of both two-mutant constructs show that the mutations do not perturb local structure, but side chain conformations at the Arg-498/Thr-499 position differ from those of the mimicked enzyme. A model for differential recognition of neurotensin based on differences in surface charge distribution in the substrate binding sites is proposed. The model is supported by the finding that reducing the positive charge on the peptide results in cleavage at both hydrolysis sites.
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Affiliation(s)
- Eun Jeong Lim
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536
| | - Sowmya Sampath
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536
| | - Jerry Coll-Rodriguez
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536
| | - Jack Schmidt
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536
| | - Kallol Ray
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536
| | - David W Rodgers
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536.
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16
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Gan L. Therapeutic potential of amyloid β-degrading enzymes in Alzheimer’s disease. FUTURE NEUROLOGY 2007. [DOI: 10.2217/14796708.2.2.133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Li Gan
- Gladstone Institute of Neurological Disease, University of California, San Francisco, CA 94158, USA
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17
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Yamin R, Bagchi S, Hildebrant R, Scaloni A, Widom RL, Abraham CR. Acyl peptide hydrolase, a serine proteinase isolated from conditioned medium of neuroblastoma cells, degrades the amyloid-? peptide. J Neurochem 2007; 100:458-67. [PMID: 17241160 DOI: 10.1111/j.1471-4159.2006.04251.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Considerable evidence indicates that the amyloid-beta (Abeta) peptide, a proteolytic fragment of the amyloid precursor protein, is the pathogenic agent in Alzheimer's disease (AD). A number of proteases have been reported as capable of degrading Abeta, among them: neprilysin, insulin-degrading enzyme, endothelin-converting enzyme-1 and -2, angiotensin-converting enzyme and plasmin. These proteases, originating from a variety of cell types, degrade Abeta of various conformational states and in different cellular locations. We report here the isolation of a serine protease from serum-free conditioned medium of human neuroblastoma cells. Tandem mass spectrometry (MS/MS)-based sequencing of the isolated protein identified acyl peptide hydrolase (APH; EC3.4.19.1) as the active peptidase. APH is one of four members of the prolyl oligopeptidase family of serine proteases expressed in a variety of cells and tissues, including erythrocytes, liver and brain, but its precise biological activity is unknown. Here, we describe the identification of APH as an Abeta-degrading enzyme, and we show that the degradation of Abeta by APH isolated from transfected cells is inhibited by APH-specific inhibitors, as well as by synthetic Abeta peptide. In addition, we cloned APH from human brain and from neuroblastoma cells. Most importantly, our results indicate that APH expression in AD brain is lower than in age-matched controls.
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Affiliation(s)
- Rina Yamin
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
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18
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Aguilar MI, Purcell AW, Devi R, Lew R, Rossjohn J, Smith AI, Perlmutter P. β-Amino acid-containing hybrid peptides—new opportunities in peptidomimetics. Org Biomol Chem 2007; 5:2884-90. [PMID: 17728852 DOI: 10.1039/b708507a] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hybrid peptides consisting of alpha-amino acids with judiciously placed beta-amino acids show great promise as peptidomimetics in an increasing range of therapeutic applications. This reflects a combination of increased stability, high specificity and relative ease of synthesis.
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Affiliation(s)
- Marie-Isabel Aguilar
- Department of Biochemistry & Molecular Biology, Monash University, PO Box 13d, Victoria, 3800, Australia
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19
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Abstract
Neuropeptides are neurotransmitters and modulators distributed in the central nervous system (CNS) and peripheral nervous system. Their abnormalities cause neurological and mental diseases. Neuropeptidases are enzymes crucial for the biosynthesis and biodegradation of neuropeptides. We here focus on the peptidases involved in the metabolism of the well-studied opioid peptides. Bioactive enkephalins are formed from propeptides by processing enzymes—prohormone thiol protease, prohormone convertase 1 and 2 (PC 1 and 2), carboxypeptidase H/E, and Arg/Lys aminopeptidase. After they exert their biological effects, enkephalins are likely to be inactivated by degrading enzymes—angiotensin-converting enzyme (ACE), aminopeptidase N (APN), puromycin-sensitive aminopeptidase (PSA), and endopeptidase 24.11. Recently, a neuron-specific aminopeptidase (NAP), which was a putative enkephalin-inactivating enzyme at the synapses, was found. Neuropeptidases are useful drug targets and their inhibitors can be therapeutic. Synthetic anti-enkephalinases and anti-aminopeptidases are being developed. They are potent analgesics but have fewer side effects than the opiates.
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Affiliation(s)
- Abel Lajtha
- grid.250263.00000000121894777Center for Neurochemistry, Nathan S. Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, Newyork, 10962, USA
| | - Naren Banik
- grid.259828.c0000000121893475Department of Neurosciences Division of Neurology, Medical University of South Carolina, 96 Jonathan Lucas Street Suite 309, Charleston, SC 29425, USA
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20
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Mueller-Steiner S, Zhou Y, Arai H, Roberson ED, Sun B, Chen J, Wang X, Yu G, Esposito L, Mucke L, Gan L. Antiamyloidogenic and neuroprotective functions of cathepsin B: implications for Alzheimer's disease. Neuron 2006; 51:703-14. [PMID: 16982417 DOI: 10.1016/j.neuron.2006.07.027] [Citation(s) in RCA: 305] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 06/19/2006] [Accepted: 07/28/2006] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease (AD) may result from the accumulation of amyloid-beta (Abeta) peptides in the brain. The cysteine protease cathepsin B (CatB) is associated with amyloid plaques in AD brains and has been suspected to increase Abeta production. Here, we demonstrate that CatB actually reduces levels of Abeta peptides, especially the aggregation-prone species Abeta1-42, through proteolytic cleavage. Genetic inactivation of CatB in mice with neuronal expression of familial AD-mutant human amyloid precursor protein (hAPP) increased the relative abundance of Abeta1-42, worsening plaque deposition and other AD-related pathologies. Lentivirus-mediated expression of CatB in aged hAPP mice reduced preexisting amyloid deposits, even thioflavin S-positive plaques. Under cell-free conditions, CatB effectively cleaved Abeta1-42, generating C-terminally truncated Abeta peptides that are less amyloidogenic. Thus, CatB likely fulfills antiamyloidogenic and neuroprotective functions. Insufficient CatB activity might promote AD; increasing CatB activity could counteract the neuropathology of this disease.
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Affiliation(s)
- Sarah Mueller-Steiner
- Gladstone Institute of Neurological Disease, University of California, San Francisco, 1650 Owens Street, 94158, USA
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21
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ABRAHAM CARMELAR, McGRAW WALKERT, SLOT FRANCHOT, YAMIN RINA. α1-Antichymotrypsin Inhibits Aβ Degradation in Vitro and in Vivo. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.2000.tb06930.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Lee SY, Ha TY, Son DJ, Kim SR, Hong JT. Effect of sesaminol glucosides on β-amyloid-induced PC12 cell death through antioxidant mechanisms. Neurosci Res 2005; 52:330-41. [PMID: 15885833 DOI: 10.1016/j.neures.2005.04.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 04/12/2005] [Accepted: 04/13/2005] [Indexed: 10/25/2022]
Abstract
Several lines of evidence support that beta-amyloid (Abeta)-induced neurotoxicity is mediated through the generation of reactive oxygen species (ROS) and elevation of intracellular calcium. In this study, we have investigated protective effects of sesaminol glucosides on Abeta-induced oxidative cell death in cultured rat pheochromocytoma (PC12) cells. Sesaminol glucoside (50-250microg/ml) decreased Abeta(25-35)-induced ROS generation, formation of 8-oxodG, a form of oxidative DNA and elevation of intracellular calcium level concomitant with prevention of apoptotic cell death dose dependently. Sesaminol glucoside (50-250microg/ml) also effectively decreased Abeta1-42 and ADDL form of Abeta1-42 as well as the combination of H2O2 with FeSO4-induced cell damages. In mechanistic study, sesaminol glucosides attenuated Abeta25-35-induced activation of redox transcription factor nuclear factor-kappaB NF-kappaB through inhibition of p50 translocation and IkappaB phosphorylation, and blocked NF-kappaB-dependent luciferase activity in addition to the inhibitory effect on Abeta25-35-induced activation of ERK kinase signal pathway. Consistent with the inhibitory effect on Abeta25-35-induced stress-induced cell death, sesaminol glucosides decreased expression of pro-apoptotic gene p53, and Bax and caspase-3, but enhanced expression of anti-apoptotic Bcl-2. Moreover, the protective effects of sesaminol glucoside on Abeta25-35-induced ROS generation, NF-kappaB activation and cell death were further enhanced with glutathione. This study therefore suggests that sesaminol glucosides have protective effect on Abeta-induced neuronal cell death, and its effect may be through antioxidative property.
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Affiliation(s)
- Sun Young Lee
- College of Pharmacy, Chungbuk National University, 48 Gaesin-dong, Heungduk-gu, Cheongju, Chungbuk 361-763, Republic of Korea
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23
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Ostergren A, Svensson AL, Lindquist NG, Brittebo EB. Dopamine melanin-loaded PC12 cells: a model for studies on pigmented neurons. ACTA ACUST UNITED AC 2005; 18:306-14. [PMID: 16029423 DOI: 10.1111/j.1600-0749.2005.00239.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The most conspicuous feature in idiopathic parkinsonism is the degeneration of pigmented neurons in the substantia nigra. A major problem for the study of the significance of neuromelanin for the development of parkinsonism is that common experimental animals lack neuromelanin in substantia nigra. The aim of this study was to develop an in vitro model that could be used to study the role of neuromelanin in chemically induced toxicity in dopaminergic cells. Cultured neuron-like PC12 cells were exposed to synthetic dopamine melanin (0-1.0 mg/ml) for 48 h, resulting in uptake of dopamine melanin particles into the cells. The intracellular distribution of dopamine melanin granules was similar to that found in neuromelanin-containing neurons. Dopamine melanin, up to 0.5 mg/ml, had negligible effects on ultrastructure, induction of the endoplasmic reticulum-stress protein glucose regulating protein 78, activation of caspase-3 and cell viability. The decreased cell viability in response to the cytotoxic peptide amyloid-beta25-35 was similar in melanin-loaded cells and in control cells without melanin. The results of the studies suggest that melanin-loaded PC12 cells can serve as an in vitro model for studies on the role of neuromelanin for the toxicity of chemicals, in particular neurotoxicants with melanin affinity, in pigmented neurons.
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Affiliation(s)
- Anna Ostergren
- Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
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24
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Carreño FR, Goñi CN, Castro LM, Ferro ES. 14-3-3 epsilon modulates the stimulated secretion of endopeptidase 24.15. J Neurochem 2005; 93:10-25. [PMID: 15773901 DOI: 10.1111/j.1471-4159.2004.02967.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Endopeptidase 24.15 (ep24.15: EC3.4.24.15), a secreted protein involved in peptide metabolism, is unusual in that it does not contain a signal peptide sequence. In this work, we describe the physical interaction between ep24.15 and 14-3-3 epsilon, one isoform of a family of ubiquitous phosphoserine/threonine-scaffold proteins that organizes cell signaling and is involved in exocytosis. The interaction between ep24.15 and 14-3-3 epsilon increased following phosphorylation of ep24.15 at Ser(644) by protein kinase A (PKA). The co-localization of ep24.15 and 14-3-3 epsilon was increased by exposure of HEK293 cells (human embryonic kidney cells) to forskolin (10 microm). Overexpression of 14-3-3 epsilon in HEK293 cells almost doubled the secretion of ep24.15 stimulated by A23187 (7.5 microm) from 10%[1.4 +/- 0.24 AFU/(min 10(6) cells)] to 19%[2.54 +/- 0.24 AFU/(min 10(6) cells)] (p < 0.001) of the total intracellular enzyme activity. Treatment with forskolin had a synergistic effect on the A23187-stimulated secretion of ep24.15 that was totally blocked by the PKA inhibitor KT5720. The ep24.15 point mutation S644A reduced the co-localization of ep24.15 and 14-3-3 in stably transfected HEK293 cells. Indeed, secretion of the ep24.15 S644A mutant from these cells was only slightly stimulated by A23187 and insensitive to forskolin, in contrast to that of the wild type enzyme. Together, these data suggest that prior interaction with 14-3-3 is an important step in the unconventional stimulated secretion of ep24.15.
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Affiliation(s)
- Flávia R Carreño
- Department of Cell Biology and Development, Cell Biology Program, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil
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25
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Nilsson LNG, Arendash GW, Leighty RE, Costa DA, Low MA, Garcia MF, Cracciolo JR, Rojiani A, Wu X, Bales KR, Paul SM, Potter H. Cognitive impairment in PDAPP mice depends on ApoE and ACT-catalyzed amyloid formation. Neurobiol Aging 2004; 25:1153-67. [PMID: 15312961 DOI: 10.1016/j.neurobiolaging.2003.12.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2003] [Revised: 12/08/2003] [Accepted: 12/09/2003] [Indexed: 01/27/2023]
Abstract
Biochemical and genetic studies indicate that the inflammatory proteins, apolipoprotein E (ApoE) and alpha(1)-antichymotrypsin (ACT) are important in the pathogenesis of Alzheimer's disease (AD). Using several lines of multiply transgenic/knockout mice we show here that murine ApoE and human ACT separately and synergistically facilitate both diffuse A beta immunoreactive and fibrillar amyloid deposition and thus also promote cognitive impairment in aged PDAPP(V717F) mice. The degree of cognitive impairment is highly correlated with the ApoE- and ACT-dependent hippocampal amyloid burden, with PDAPP mice lacking ApoE and ACT having little amyloid and little learning disability. A analysis of young mice before the onset of amyloid formation shows that steady-state levels of monomeric A beta peptide are unchanged by ApoE or ACT. These data suggest that the process or product of amyloid formation is more critical than monomeric A beta for the neurological decline in AD, and that the risk factors ApoE and ACT participate primarily in disease processes downstream of APP processing.
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Affiliation(s)
- Lars N G Nilsson
- Department of Biochemistry and Molecular Biology, Suncoast Gerontology Center, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
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26
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Feng Z, Zhang JT. Protective effect of melatonin on beta-amyloid-induced apoptosis in rat astroglioma C6 cells and its mechanism. Free Radic Biol Med 2004; 37:1790-801. [PMID: 15528038 DOI: 10.1016/j.freeradbiomed.2004.08.023] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 07/29/2004] [Accepted: 08/26/2004] [Indexed: 12/22/2022]
Abstract
Astrocytosis is a common feature of amyloid plaques. The Abeta-astrocyte interaction produces a detrimental effect on neurons, which may contribute to neurodegeneration in Alzheimer disease (AD). The regulation of astrocyte apoptosis is essential to physiological and pathological processes in the CNS. Melatonin is a potent antioxidant and free radical scavenger. Previously, we showed that melatonin alleviated the learning and memory deficits in the APP 695 transgenic mouse model of AD. In this study, the importance of melatonin in the management of Abeta-induced apoptosis in an astrocyte-like cell is discussed. We found that rat astroglioma C6 cells treated with Abeta25-35 or Abeta1-42 undergo apoptosis and that melatonin pretreatment at 10(-5), 10(-6), and 10(-7) M significantly attenuates Abeta25-35- or Abeta1-42-induced apoptosis. The antiapoptotic effects of melatonin were extremely reproducible and corroborated by multiple quantitative methods, including an MTT cell viability assay, Hoechst 33342 nuclei staining, DNA fragmentation analysis, and flow cytometric analysis. In addition, melatonin effectively suppressed Abeta1-42-induced nitric oxide formation, remarkably prevented Abeta1-40-induced intracellular calcium overload, and significantly alleviated Abeta1-40-induced membrane rigidity. Our results demonstrate that, in addition to the beneficial effects of providing direct antioxidant protection to neurons, melatonin may enhance neuroprotection against Abeta-induced neurotoxicity by promoting the survival of glial cells.
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Affiliation(s)
- Zheng Feng
- Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 10050, People's Republic of China.
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27
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Ray K, Hines CS, Coll-Rodriguez J, Rodgers DW. Crystal structure of human thimet oligopeptidase provides insight into substrate recognition, regulation, and localization. J Biol Chem 2004; 279:20480-9. [PMID: 14998993 DOI: 10.1074/jbc.m400795200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thimet oligopeptidase (TOP) is a zinc metallopeptidase that metabolizes a number of bioactive peptides and degrades peptides released by the proteasome, limiting antigenic presentation by MHC class I molecules. We present the crystal structure of human TOP at 2.0-A resolution. The active site is located at the base of a deep channel that runs the length of the elongated molecule, an overall fold first seen in the closely related metallopeptidase neurolysin. Comparison of the two related structures indicates hinge-like flexibility and identifies elements near one end of the channel that adopt different conformations. Relatively few of the sequence differences between TOP and neurolysin map to the proposed substrate-binding site, and four of these variable residues may account for differences in substrate specificity. In addition, a loop segment (residues 599-611) in TOP differs in conformation and degree of order from the corresponding neurolysin loop, suggesting it may also play a role in activity differences. Cysteines thought to mediate covalent oligomerization of rat TOP, which can inactivate the enzyme, are found to be surface-accessible in the human enzyme, and additional cysteines (residues 321,350, and 644) may also mediate multimerization in the human homolog. Disorder in the N terminus of TOP indicates it may be involved in subcellular localization, but a potential nuclear import element is found to be part of a helix and, therefore, unlikely to be involved in transport. A large acidic patch on the surface could potentially mediate a protein-protein interaction, possibly through formation of a covalent linkage.
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Affiliation(s)
- Kallol Ray
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA
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28
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Kim SI, Grum-Tokars V, Swanson TA, Cotter EJ, Cahill PA, Roberts JL, Cummins PM, Glucksman MJ. Novel roles of neuropeptide processing enzymes: EC3.4.24.15 in the neurome. J Neurosci Res 2003; 74:456-67. [PMID: 14598322 DOI: 10.1002/jnr.10779] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neuropeptide processing metalloenzymes, such as angiotensin converting enzyme, neprilysin, endothelin converting enzyme, neurolysin, and EC3.4.24.15 (EP24.15), are central to the formation and degradation of bioactive peptides. We present EP24.15 as a paradigm for novel functions ascribed to these enzymes in the neurome. Although the neurome typically encompasses proteomes of the brain and central nervous system, exciting new roles of these neuropeptidases have been demonstrated in other organ systems. We discuss the involvement of EP24.15 with clinical sequelae involving the use of gonadotropin-releasing hormone (GnRH; LHRH) analogs that act as enzyme inhibitors, in vascular physiology (blood pressure regulation), and in the hematologic system (immune surveillance). Hemodynamic forces, such as cyclic strain and shear stress, on vascular cells, induce an increase in EP24.15 transcription, suggesting that neuropeptidase-mediated hydrolysis of pressor/depressor peptides is likely regulated by changes in hemodynamic force and blood pressure. Lastly, EP24.15 regulates surface expression of major histocompatibility complex Class I proteins in vivo, suggesting that EP24.15 may play an important role in maintenance of immune privilege in sites of increased endogenous expression. In these extraneural systems, regulation of both neuropeptide and other peptide substrates by neuropeptidases indicates that the influence of these enzymes may be more global than was anticipated previously, and suggests that their attributed role as neuropeptidases underestimates their physiologic actions in the neural system.
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Affiliation(s)
- S I Kim
- Midwest Proteome Center, Department of Biochemistry and Molecular Biology, Finch University of Health Sciences/Chicago Medical School, North Chicago, Illinois 60064, USA
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29
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Morrison LS, Pierotti AR. Thimet oligopeptidase expression is differentially regulated in neuroendocrine and spermatid cell lines by transcription factor binding to SRY (sex-determining region Y), CAAT and CREB (cAMP-response-element-binding protein) promoter consensus sequences. Biochem J 2003; 376:189-97. [PMID: 12911328 PMCID: PMC1223746 DOI: 10.1042/bj20030792] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2003] [Revised: 08/07/2003] [Accepted: 08/11/2003] [Indexed: 11/17/2022]
Abstract
The zinc metalloprotease thimet oligopeptidase (EP24.15) is found predominantly in the neuroendocrine-gonadal axis where it is implicated in the processing of bioactive peptides, including GnRH (gonadotropin-releasing hormone), beta-neoendorphin, alpha-neoendorphin and dynorphin(1-8), the progression of spermatogenesis and the normal clearance of beta-amyloid in brain cells. Regulation of the enzyme's activity may occur in part by phosphorylation and redox disruption of intermolecular disulphide bridges. The elevated levels of both EP24.15 activity and mRNA within testicular and neuroendocrine tissues indicate that EP24.15 gene expression is differentially regulated. In the present paper, we present a detailed analysis of the rat EP24.15 promoter region previously isolated and partially characterized in this laboratory. Employing site-directed mutagenesis to create a series of promoter deletions and full-length promoter mutants, and measuring their activity in luciferase reporter gene and electrophoretic mobility-shift assays, we have shown that the transcription of the EP24.15 gene is differentially regulated in neuroendocrine and spermatid cell lines by transcription factor binding to SRY (sex-determining region Y), CAAT and CREB (cAMP-response-element-binding protein) promoter consensus sequences. The key to identifying the in vivo role of thimet oligopeptidase is likely to be found within the mechanisms by which it is regulated, and it is therefore of particular significance that EP24.15 expression is regulated by SRY and CREB/CREM (cAMP-response element modulator), the principle testes-determining protein and the major orchestrator of spermatogenesis respectively.
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Affiliation(s)
- Lesley S Morrison
- Biological & Biomedical Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, Scotland, UK
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30
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Abstract
Metalloendopeptidase EC 3.4.24.15 (EP24.15, thimet oligopeptidase) is a neuropeptide-metabolizing peptidase expressed throughout the body, but primarily in the brain, gonads, and pituitary. For EP24.15 to have its greatest effect upon peptides in the periphery, it must be targeted and released into the extracellular space. Western blot analysis of fractions taken from discontinuous sucrose density gradients carried out on crude plasma membrane fractions from AtT-20 cells reveals colocalization of EP24.15 and flotillin-1, a known lipid raft marker. Further analysis revealed that an intracellular membrane marker and non-lipid raft, plasma membrane marker, failed to colocalize, supporting EP24.15/lipid raft association. Furthermore, EP24.15 immunoreactivity in lipid raft fractions generated from cells treated with methyl beta-cyclodextrin (MbetaCD) was greatly reduced. Finally, treatment with MbetaCD resulted in the accumulation of EP24.15 in the media of drug-treated cells over vehicle-treated cells, suggesting that a large percentage of EP24.15 associating with lipid rafts resides on the extracellular surface of the plasma membrane. With this exofacial localization, EP24.15 could have ample access to neuropeptides not only in the immediate microenvironment, but the ability to degrade or modify peptides bound for receptor interaction.
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Affiliation(s)
- Nathaniel A Jeske
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Ahmed MM, Yamamoto M, Chikuma T, Rahman MK, Kato T. Dose-dependent effect of MK-801 on the levels of neuropeptides processing enzymes in rat brain regions. Neurosci Res 2003; 47:177-89. [PMID: 14512142 DOI: 10.1016/s0168-0102(03)00197-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The appropriate levels of neuropeptides and their processing enzyme activities are required to continue a normal cell life, and the dysfunction of these peptides and enzymes are responsible for many neuronal abnormalities. Systemic administration of (+) MK-801 (dizocilpine maleate), a noncompetitive N-methyl-[D]-aspartate (NMDA) receptor antagonist, causes both neuroprotective and neurotoxic activities depending on doses and conditions. In the present study, we investigated the dose dependent effect of (+) MK-801 on prolyl endopeptidase (PEP), endopeptidase EC 24.15 (EP 24.15) and beta-D-glucuronidase activities as well as the protein levels of EP 24.15 and neuron specific enolase (NSE) in the posterior cingulate/retrosplenial cortices (PC/RSC), hippocampus, frontal cortex and striatum of female rats 3 days after the treatment. The activity of PEP was significantly increased compared with controls (saline) in the PC/RSC at 1.0 and 5.0 mg/kg doses, and in the frontal cortex at 5.0 mg/kg dose. beta-D-Glucuronidase activity was dose-dependently increased in all brain regions examined. The activity of EP 24.15 was unchanged in all regions after the treatment, whereas the Western blot analysis for EP 24.15 showed the increased protein level in the PC/RSC. These results suggest that a low dose treatment with MK-801 causes neurotoxicity in the PC/RSC and hippocampus, and the high dose treatment causes neurotoxicity in all the brain regions examined.
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Affiliation(s)
- Md Mahiuddin Ahmed
- Laboratory of Natural Information Science, Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Kanazawa-Ku, Yokohama 236-0027, Japan
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32
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York IA, Mo AXY, Lemerise K, Zeng W, Shen Y, Abraham CR, Saric T, Goldberg AL, Rock KL. The cytosolic endopeptidase, thimet oligopeptidase, destroys antigenic peptides and limits the extent of MHC class I antigen presentation. Immunity 2003; 18:429-40. [PMID: 12648459 DOI: 10.1016/s1074-7613(03)00058-x] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Most antigenic peptides presented on MHC class I molecules are generated by proteasomes during protein breakdown. It is unknown whether these peptides are protected from destruction by cytosolic peptidases. In cytosolic extracts, most antigenic peptides are degraded by the metalloendopeptidase, thimet oligopeptidase (TOP). We therefore examined whether TOP destroys antigenic peptides in vivo. When TOP was overexpressed in cells, class I presentation of antigenic peptides was reduced. In contrast, TOP overexpression didn't reduce presentation of peptides generated in the endoplasmic reticulum or endosomes. Conversely, preventing TOP expression with siRNA enhanced presentation of antigenic peptides. TOP therefore plays an important role in vivo in degrading peptides released by proteasomes and is a significant factor limiting the extent of antigen presentation.
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Affiliation(s)
- Ian A York
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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33
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Yamamoto M, Chikuma T, Yamashita A, Yamaguchi M, Hojo H, Ozeki Y, Ahmed M, Kato T. Anterograde axonal transport of endopeptidase 24.15 in rat sciatic nerves. Neurochem Int 2003; 42:231-7. [PMID: 12427477 DOI: 10.1016/s0197-0186(02)00092-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Axonal transport of endopeptidase 24.15 (EP24.15), a putative neuropeptide degrading-enzyme, was examined in the proximal, middle, and distal segments of rat sciatic nerves using a double ligation technique. At 48h after ligation, a significant amount of the axonal transport of EP24.15 activity was found in the proximal segment, while axonal transport of deamidase activity, a lysosomal enzyme, increased in both proximal and distal segments. Western blot analysis of EP24.15 showed that EP24.15 immunoreactivity in the proximal segment was 1.8-fold higher than that in the middle segment. The immunohistochemical analysis of the segments also showed an increase in the immunoreactive EP24.15 in the proximal segment in comparison with that in the middle segment. In the distal segment, no axonal transport of EP24.15 was found in all methods examined, indicating that EP24.15 is mainly transported by an anterograde axonal flow. These observations suggest that EP24.15 may be involved in the metabolism of neuropeptides in nerve terminals or synaptic clefts.
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Affiliation(s)
- Masaru Yamamoto
- Laboratory of Natural Information Science, Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan
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Eckman EA, Watson M, Marlow L, Sambamurti K, Eckman CB. Alzheimer's disease beta-amyloid peptide is increased in mice deficient in endothelin-converting enzyme. J Biol Chem 2003; 278:2081-4. [PMID: 12464614 DOI: 10.1074/jbc.c200642200] [Citation(s) in RCA: 192] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The abnormal accumulation of beta-amyloid (Abeta) in the brain is an early and invariant feature in Alzheimer's disease (AD) and is believed to play a pivotal role in the etiology and pathogenesis of the disease. As such, a major focus of AD research has been the elucidation of the mechanisms responsible for the generation of Abeta. As with any peptide, however, the degree of Abeta accumulation is dependent not only on its production but also on its removal. In cell-based and in vitro models we have previously characterized endothelin-converting enzyme-1 (ECE-1) as an Abeta-degrading enzyme that appears to act intracellularly, thus limiting the amount of Abeta available for secretion. To determine the physiological significance of this activity, we analyzed Abeta levels in the brains of mice deficient for ECE-1 and a closely related enzyme, ECE-2. Significant increases in the levels of both Abeta40 and Abeta42 were found in the brains of these animals when compared with age-matched littermate controls. The increase in Abeta levels in the ECE-deficient mice provides the first direct evidence for a physiological role for both ECE-1 and ECE-2 in limiting Abeta accumulation in the brain and also provides further insight into the factors involved in Abeta clearance in vivo.
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35
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Bates KA, Fonte J, Robertson TA, Martins RN, Harvey AR. Chronic gliosis triggers Alzheimer's disease-like processing of amyloid precursor protein. Neuroscience 2002; 113:785-96. [PMID: 12182886 DOI: 10.1016/s0306-4522(02)00230-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alzheimer's disease is a progressively dementing illness characterized by the extracellular accumulation and deposition of beta-amyloid. Early onset Alzheimer's disease is linked to mutations in three genes, all of which lead to increased beta-amyloid production. Inflammatory changes and gliosis may also play a role in the disease process, but the importance of these reactive events remains unclear. We recently reported that chronic cortical gliosis in heterotopic fetal rat cortical transplants is associated with significant changes in the levels of some of the proteins implicated in the pathogenesis of Alzheimer's disease. Because rodent beta-amyloid does not form extracellular amyloid deposits, we have now extended this model of chronic cortical gliosis to transgenic mice expressing the Swedish mutant form of human amyloid precursor protein. In addition, apolipoprotein E knockout mice were used to elucidate the role of this protein in reactive gliosis. The expression of mutant and murine proteins was assayed 6 or 10 months after transplantation using immunohistochemical and western blot methods. Heterotopic transplantation of fetal cortex onto the midbrain of neonatal mice consistently resulted in reactive gliosis, independent of apolipoprotein E status. In contrast, in homotopic cortex-to-cortex grafts there was little alteration in glial reactivity, a result similar to that obtained previously in rats. By 10 months post-transplantation the level of presenilin-1 expression was lower in heterotopic grafts than in host cortex and there was increased expression of transgenic amyloid precursor protein, but only in the gliotic cortex-to-midbrain grafts. Most importantly, increased levels of beta-amyloid, and particularly its precursor, C-99, were selectively found in these heterotopic transplants. Our results show that chronic gliosis is associated with altered processing of the amyloid precursor protein in vivo and thus may initiate or exacerbate pathological changes associated with Alzheimer's disease.
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Affiliation(s)
- K A Bates
- School of Anatomy and Human Biology, The University of Western Australia, Nedlands, WA 6009, Australia
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Janciauskiene S, Sun YX, Wright HT. Interactions of A beta with endogenous anti-inflammatory agents: a basis for chronic neuroinflammation in Alzheimer's disease. Neurobiol Dis 2002; 10:187-200. [PMID: 12270682 DOI: 10.1006/nbdi.2002.0519] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- S Janciauskiene
- Department of Medicine, University Hospital Malmö, 20502 Malmö, Sweden
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37
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Morelli L, Llovera R, Ibendahl S, Castaño EM. The degradation of amyloid beta as a therapeutic strategy in Alzheimer's disease and cerebrovascular amyloidoses. Neurochem Res 2002; 27:1387-99. [PMID: 12512943 DOI: 10.1023/a:1021679817756] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The deposition of 4-kDa amyloid beta peptide in the brain is a prominent feature of several human diseases. Such process is heterogeneous in terms of causative factors, biochemical phenotype, localization and clinical manifestations. Amyloid beta accumulates in the neuropil or within the walls of cerebral vessels, and associates with dementia or stroke, both hereditary and sporadic. Amyloid beta is normally released by cells as soluble monomeric-dimeric species yet, under pathological conditions, it self-aggregates as soluble oligomers or insoluble fibrils that may be toxic to neurons and vascular cells. Lowering amyloid beta levels may be achieved by inhibiting its generation from the amyloid beta-precursor protein or by promoting its clearance by transport or degradation. We will summarize recent findings on brain proteases capable of degrading amyloid beta with a special focus on those enzymes for which there is genetic, transgenic or biochemical evidence suggesting that they may participate in the proteolysis of amyloid beta in vivo. We will also put in perspective their possible utilization as therapeutic agents in amyloid beta diseases.
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Affiliation(s)
- Laura Morelli
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), CONICET, Cátedra de Química Biológica Patológica, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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Bastiani M, Hillebrand S, Horn F, Kist TBL, Guimarães JA, Termignoni C. Cattle tick Boophilus microplus salivary gland contains a thiol-activated metalloendopeptidase displaying kininase activity. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2002; 32:1439-1446. [PMID: 12530211 DOI: 10.1016/s0965-1748(02)00064-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This work reports on the characterization of a metalloendopeptidase kininase present in Boophilus microplus salivary glands. Using the guinea pig ileum assay, salivary gland whole extracts (SGE) were found to have a potent kininase activity. Ion-exchange chromatography separated two kininase activities from SGE. The major enzymatic component, eluted at lower ionic strength, was named BooKase (Boophilus Kininase). Analysis of the hydrolysis products by capillary electrophoresis identified Phe5-Ser6 as the only hydrolyzable peptide bond in bradykinin after BooKase treatment. This is the same specificity as the mammalian thimet oligoendopeptidase (EC 3.4.24.15). Like this enzyme, BooKase is also a metallo-peptidase (requires Mn2+) and is activated by-SH protecting reagents. In addition, BooKase was partially inhibited by cFP-AAF-pAB, a specific inhibitor of thimet oligopeptidase. Contrary to other kininases, BooKase had no activity upon angiontensin I. Our results show that BooKase behaves as a typical peptidase with kinase activity.
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Affiliation(s)
- Michele Bastiani
- Centro de Biotecnologia, Universidade, Departamento de Biofísica, Universidade Federal do Rio Grande do Sul. Caixa Postal 15005, 91501-970, Porto Alegre, Brazil
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39
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Abstract
Peptidases play a vital and often highly specific role in the physiological and pathological generation and termination of peptide hormone signals. The thermolysin-like family of metalloendopeptidases involved in the extracellular processing of neuroendocrine and cardiovascular peptides are of particular significance, reflecting both their specificity for particular peptide substrates and their utility as therapeutic targets. Although the functions of the membrane-bound members of this family, such as angiotensin-converting enzyme and neutral endopeptidase, are well established, a role for the predominantly soluble family members in peptide metabolism is only just emerging. This review will focus on the biochemistry, cell biology, and physiology of the soluble metalloendopeptidases EC 3.4.24.15 (thimet oligopeptidase) and EC 3.4.24.16 (neurolysin), as well as presenting evidence that both peptidases play an important role in such diverse functions as reproduction, nociception, and cardiovascular homeostasis.
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40
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Mohajeri MH, Wollmer MA, Nitsch RM. Abeta 42-induced increase in neprilysin is associated with prevention of amyloid plaque formation in vivo. J Biol Chem 2002; 277:35460-5. [PMID: 12105192 DOI: 10.1074/jbc.m202899200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Brain beta-amyloid plaques are principal targets for the development of treatments designed to slow the progression of Alzheimer's disease. Intracranial injections of synthetic beta-amyloid peptide (Abeta(42)) in transgenic mice expressing the Alzheimer's disease-causing Swedish APP double mutations increased neuronal levels of neprilysin, a metalloendopeptidase that degrades Abeta(42) in vivo, on mRNA and protein level. This increase was associated with significant reductions in brain levels of Abeta and with almost complete prevention of amyloid plaque formation throughout the brain. In addition, astrogliosis normally associated with amyloidosis was significantly reduced. Our results suggest that up-regulation of neprilysin in brain may represent an opportunity to reduce or prevent amyloid plaque formation in vivo.
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Affiliation(s)
- M Hasan Mohajeri
- Division of Psychiatry Research, University of Zurich, August Forel Strasse 1, 8008 Zurich, Switzerland.
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41
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Steer D, Lew R, Perlmutter P, Smith AI, Aguilar MI. Inhibitors of metalloendopeptidase EC 3.4.24.15 and EC 3.4.24.16 stabilized against proteolysis by the incorporation of beta-amino acids. Biochemistry 2002; 41:10819-26. [PMID: 12196021 DOI: 10.1021/bi0203334] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzyme EC 3.4.24.15 (EP 24.15) is a zinc metalloendopeptidase whose precise function in vivo remains unknown but is thought to participate in the regulated metabolism of a number of specific neuropeptides. The lack of stable and selective inhibitors has hindered the determination of the exact function of EP 24.15. Of the limited number of EP 24.15 inhibitors that have been developed, N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate (CFP) is the most widely studied. CFP is a potent and specific inhibitor, but it is unstable in vivo due to cleavage between the alanine and tyrosine residues by the enzyme neprilysin (EP 24.11). This cleavage by EP 24.11 generates a potent inhibitor of angiotensin converting enzyme, thereby limiting the use of CFP for in vivo studies. To develop specific inhibitors of EP 24.15 that are resistant to in vitro and potentially in vivo proteolysis by EP 24.11, this study incorporated beta-amino acids replacing the Ala-Tyr scissile alpha-amino acids of CFP. Both C2 and C3 substituted beta-amino acids were synthesized and substituted at the EP 24.11 scissile Ala-Tyr bond. Significant EP 24.15 inhibitory activity was observed with some of the beta-amino acid containing analogues. Moreover, binding to EP 24.11 was eliminated, thus rendering all analogues containing beta-amino acids resistant to degradation by EP 24.11. Selective inhibition of either EP 24.15 or EP 24.16 was also observed with some analogues. The results demonstrated the use of beta-amino acids in the design of inhibitors of EP 24.15 and EP 24.16 with K(i)'s in the low micromolar range. At the same time, these analogues were resistant to cleavage by the related metalloendopeptidase EP 24.11, in contrast to the alpha-amino acid based parent peptide. This study has therefore clearly shown the potential of beta-amino acids in the design of stable enzyme inhibitors and their use in generating molecules with selectivity between closely related enzymes.
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Affiliation(s)
- David Steer
- Department of Biochemistry and Molecular Biology, P.O. Box 13D, Monash University, Clayton, Vic 3800, Australia
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42
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Abstract
Biochemical and genetic evidence indicates the balance of biogenesis/clearance of Abeta amyloid peptides is altered in Alzheimer's disease. Abeta is derived, by two sequential cleavages, from the receptor-like amyloid precursor protein (APP). The proteases involved are beta-secretase, identified as the novel aspartyl protease BACE, and gamma-secretase, a multimeric complex containing the presenilins (PS). Gamma-secretase can release either Abeta40 or the more aggregating and cytotoxic Abeta42. Secreted Abeta peptides become either degraded by the metalloproteases insulin-degrading enzyme (IDE) and neprilysin or metabolized through receptor uptake mediated by apolipoprotein E. Therapeutic approaches based on secretase inhibition or amyloid clearance are currently under development.
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Affiliation(s)
- Geneviève Evin
- Department of Pathology, The University of Melbourne and Mental Health Research Institute, Parkville, Vic. 3010, Australia.
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43
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Choi J, Malakowsky CA, Talent JM, Conrad CC, Gracy RW. Identification of oxidized plasma proteins in Alzheimer's disease. Biochem Biophys Res Commun 2002; 293:1566-70. [PMID: 12054695 DOI: 10.1016/s0006-291x(02)00420-5] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The modification of proteins by reactive oxygen species is central to the pathology of Alzheimer's disease (AD). Previously, we have observed specific oxidized proteins in blood plasma of AD subjects [Biochem. Biophys. Res. Commun. 275 (2000) 678]. Plasma from AD subjects and age-matched controls was subjected to two-dimensional gel electrophoresis (2-DE). Oxidized proteins with new carbonyl groups were detected by reaction with 2,4-dinitrophenylhydrazine, followed by Western blotting with anti-DNP antibody. Seven principal oxidized protein spots (isoelectric point=4.7-5.5; molecular mass=45-65 kDa) were observed, with varying levels of oxidation in plasma samples from both AD and non-AD subjects. Matrix-assisted laser desorption mass spectroscopy (MALDI-TOF/MS) revealed that these oxidized proteins were isoforms of fibrinogen gamma-chain precursor protein and of alpha-1-antitrypsin precursor. These proteins exhibited a two- to sixfold greater specific oxidation index in plasma from AD subjects when compared to controls. Both these proteins have been previously implicated in the pathology of the disease. It is possible that oxidized isoforms of these proteins may serve as biomarkers for AD.
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Affiliation(s)
- Joungil Choi
- Molecular Aging Unit, Department of Molecular Biology and Immunology, University of North Texas, Health Science Center, Fort Worth, TX 76107, USA
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44
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Abstract
The steady-state level of amyloid beta-peptide (Abeta) represents a balance between its biosynthesis from the amyloid precursor protein (APP) through the action of the beta- and gamma-secretases and its catabolism by a variety of proteolytic enzymes. Recent attention has focused on members of the neprilysin (NEP) family of zinc metalloproteinases in amyloid metabolism. NEP itself degrades both Abeta(1-40) and Abeta(1-42) in vitro and in vivo, and this metabolism is prevented by NEP inhibitors. Other NEP family members, for example endothelin-converting enzyme, may contribute to amyloid catabolism and may also play a role in neuroprotection. Another metalloproteinase, insulysin (insulin-degrading enzyme) has also been advocated as an amyloid-degrading enzyme and may contribute more generally to metabolism of amyloid-forming peptides. Other candidate enzymes proposed include angiotensin-converting enzyme, some matrix metalloproteinases, plasmin and, indirectly, thimet oligopeptidase (endopeptidase-24.15). This review critically evaluates the evidence relating to proteinases implicated in amyloid catabolism. Therapeutic strategies aimed at promoting A,beta degradation may provide a novel approach to the therapy of Alzheimer's disease.
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Affiliation(s)
- Julie A Carson
- Proteolysis Research Group, School of Biochemistry and Molecular Biology, University of Leeds, UK
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45
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Sun YX, Wright HT, Janciauskiene S. Alpha1-antichymotrypsin/Alzheimer's peptide Abeta(1-42) complex perturbs lipid metabolism and activates transcription factors PPARgamma and NFkappaB in human neuroblastoma (Kelly) cells. J Neurosci Res 2002; 67:511-22. [PMID: 11835318 DOI: 10.1002/jnr.10144] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyloid-beta peptide (Abeta) and the serpin proteinase inhibitor alpha1-antichymotrypsin (ACT) are components of the amyloid plaques associated with Alzheimer's disease (AD). Abeta exists in soluble monomeric and oligomeric forms and in an insoluble polymerised fibrillar form, but it is not clear which of these plays the most important role in the etiology of AD. In vitro, Abeta(1-42) interacts with ACT, and as a result of this, ACT loses its proteinase inhibitor activity and polymerisation of Abeta(1-42) is promoted. Here we provide evidence that new molecular forms resulting from incubation of ACT with Abeta(1-42) have multiple cellular level effects on neuronal cells. The mixture of soluble Abeta and an ACT/Abeta complex formed by 2 hr incubation at a 10:1 molar ratio of Abeta:ACT strongly induce cellular proliferation and expression of transcription factors peroxisome proliferator-activated receptor-gamma (PPARgamma) and NFkappaB, and also increase uptake and depress degradation of native and oxidised low-density lipoprotein (LDL) by cells. Similar but less pronounced effects are seen when cells are exposed to the Abeta peptide alone preincubated for 2 hr. Abeta(1-42) and to a lesser extent ACT/Abeta(1-42) complex mixture prepared by 2 hr incubation both inhibit association of native LDL with cells. Neither ACT alone nor the Abeta(1-42) and ACT/Abeta(1-42) forms prepared by 24-hr incubation show any significant effects in these assays. We propose that specific molecular forms of Abeta(1-42) and ACT/Abeta(1-42) complex mixture, both dependent on the abundances of Abeta(1-42) and ACT/Abeta(1-42) in vivo and on their time of exposure to each other, have cellular effects which are important for the initiation and progression of the pathologies associated with AD.
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Affiliation(s)
- Yong-Xin Sun
- Department of Medicine, Wallenberg Laboratory, University Hospital Malmö, S-20502 Malmö, Sweden
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46
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Sudoh S, Frosch MP, Wolf BA. Differential effects of proteases involved in intracellular degradation of amyloid beta-protein between detergent-soluble and -insoluble pools in CHO-695 cells. Biochemistry 2002; 41:1091-9. [PMID: 11802707 DOI: 10.1021/bi011193l] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The deposition of amyloid beta-protein (A beta or beta A4) is a key feature of Alzheimer's disease. Most studies have focused on the generation of A beta, but little is known about the degradation of A beta. Recent reports suggest that insulin-degrading enzyme (IDE) and neutral endopeptidase (NEP) are involved in the extracellular degradation of A beta. To date, however, far less is known about the degradation of intracellular A beta. To elucidate the protease(s) responsible for the degradation of intracellular A beta, we investigated the effect of various protease inhibitors on A beta in two distinct intracellular pools (i.e., nonionic detergent-soluble and detergent-insoluble pools) in Chinese hamster ovary cells. Treatment with thiol and metal inhibitors resulted in the accumulation of intracellular A beta and oligomers in detergent-soluble and -insoluble fractions. The overexpression of thiol-metalloprotease IDE resulted in a marked reduction in levels of detergent-soluble intracellular A beta as well as extracellular A beta 40 and A beta 42. Moreover, intracellular A beta in the detergent-insoluble fraction extracted with 70% formic acid or 6 M guanidine hydrochloride decreased markedly in the cells overexpressing IDE. In contrast, expression of NEP degraded the A beta in the detergent-insoluble fraction markedly and partially degraded extracellular A beta 40 and A beta 42, but not intracellular soluble A beta. Thiorphan, an inhibitor of NEP, accumulated, albeit to a lesser extent, in insoluble A beta but not in soluble A beta. Thus, IDE appears to degrade intracellular A beta more effectively than does NEP in both the detergent-soluble and -insoluble fractions.
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Affiliation(s)
- Shinji Sudoh
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, School of Medicine, Philadelphia, Pennsylvania 19104-6082, USA
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47
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Lin H, Bhatia R, Lal R. Amyloid beta protein forms ion channels: implications for Alzheimer's disease pathophysiology. FASEB J 2001; 15:2433-44. [PMID: 11689468 DOI: 10.1096/fj.01-0377com] [Citation(s) in RCA: 484] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Amyloid beta protein (AbetaP) is the major constituent of senile plaques associated with Alzheimer's disease (AD). However, its mechanistic role in AD pathogenesis is poorly understood. Globular and nonfibrillar AbetaPs are continuously released during normal metabolism. Using techniques of atomic force microscopy, laser confocal microscopy, electrical recording, and biochemical assays, we have examined the molecular conformations of reconstituted globular AbetaPs as well as their real-time and acute effects on neuritic degeneration. Atomic force microscopy (AFM) of AbetaP1-42 shows globular structures that do not form fibers in physiological-buffered solution for up to 8 h of continuous imaging. AFM of AbetaP1-42 reconstituted in a planar lipid bilayer reveals multimeric channel-like structures. Consistent with these AFM resolved channel-like structures, biochemical analysis demonstrates that predominantly monomeric AbetaPs in solution form stable tetramers and hexamers after incorporation into lipid membranes. Electrophysiological recordings demonstrate the presence of multiple single channel currents of different sizes. At the cellular level, AbetaP1-42 allows calcium uptake and induces neuritic abnormality in a dose- and time-dependent fashion. At physiological nanomolar concentrations, rapid neuritic degeneration was observed within minutes; at micromolar concentrations, neuronal death was observed within 3-4 h. These effects are prevented by zinc (an AbetaP channel blocker) and by the removal of extracellular calcium, but are not prevented by antagonists of putative AbetaP cell surface receptors. Thus, AbetaP channels may provide a direct pathway for calcium-dependent AbetaP toxicity in AD.
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Affiliation(s)
- H Lin
- Neuroscience Research Institute, University of California, Santa Barbara, California 93016, USA
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48
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Abstract
Elevated cerebral levels of amyloid beta-protein occur universally in Alzheimer's disease, yet only a few patients show evidence of increased Abeta production. Therefore, defects in proteases that degrade Abeta could underlie some or many cases of familial and sporadic AD. This previously neglected topic has begun receiving serious attention. Understanding how proteolysis regulates Abeta levels in the cerebral cortex has implications for both the pathogenesis and the treatment of this protean disorder.
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Affiliation(s)
- D J Selkoe
- Center for Neurologic Diseases, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA.
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49
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Eckman EA, Reed DK, Eckman CB. Degradation of the Alzheimer's amyloid beta peptide by endothelin-converting enzyme. J Biol Chem 2001; 276:24540-8. [PMID: 11337485 DOI: 10.1074/jbc.m007579200] [Citation(s) in RCA: 238] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deposition of beta-amyloid (Abeta) peptides in the brain is an early and invariant feature of all forms of Alzheimer's disease. As with any secreted protein, the extracellular concentration of Abeta is determined not only by its production but also by its catabolism. A major focus of Alzheimer's research has been the elucidation of the mechanisms responsible for the generation of Abeta. Much less, however, is known about the mechanisms responsible for Abeta removal in the brain. In this report, we describe the identification of endothelin-converting enzyme-1 (ECE-1) as a novel Abeta-degrading enzyme. We show that treatment of endogenous ECE-expressing cell lines with the metalloprotease inhibitor phosphoramidon causes a 2-3-fold elevation in extracellular Abeta concentration that appears to be due to inhibition of intracellular Abeta degradation. Furthermore, we show that overexpression of ECE-1 in Chinese hamster ovary cells, which lack endogenous ECE activity, reduces extracellular Abeta concentration by up to 90% and that this effect is completely reversed by treatment of the cells with phosphoramidon. Finally, we show that recombinant soluble ECE-1 is capable of hydrolyzing synthetic Abeta40 and Abeta42 in vitro at multiple sites.
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Affiliation(s)
- E A Eckman
- Mayo Clinic Jacksonville, 4500 San Pablo Road, Jacksonville, FL 32224, USA.
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50
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Qiu Z, Naten DL, Liston JC, Yess J, Rebeck GW. A novel approach for studying endogenous abeta processing using cultured primary neurons isolated from APP transgenic mice. Exp Neurol 2001; 170:186-94. [PMID: 11421596 DOI: 10.1006/exnr.2001.7703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The central component of senile amyloid plaques in Alzheimer's disease (AD) is the beta-amyloid peptide (Abeta), derived from proteolytic processing of the amyloid precursor protein (APP). In this study, we developed an in vitro model to measure and identify soluble Abeta from primary cortical neurons. Neurons were isolated from mice transgenic for human APP695 containing the K670N, M671L double mutation. We characterized soluble Abeta using Western blot and ELISA assays. We found that the Abeta levels in conditioned media from these neurons were readily detectable and almost five times higher than in CSF. The majority of Abeta in the media was Abeta1-40; however, Abeta1-42 was also detectable. When the neurons were exposed to Phorbol 12-myristate 13-acetate (PMA), alpha1-antichymotrypsin, or alpha1-antitrypsin, the alterations of soluble Abeta levels were consistent with other models reported. Most importantly, the soluble Abeta in our model was remarkably stable, and aliquots were unchanged after prolonged incubations or repeated freeze/thaw cycles. The Abeta appeared to be monomeric by Western blot analysis. Soluble Abeta coimmunoprecipitated with endogenous mouse apolipoprotein E from the primary cultures. Taken together, our data demonstrated that using a Western blot assay to detect soluble Abeta from transgenic mouse overexpressing APP695 is sensitive, specific, and reliable and provides an accessible model for examining the neuronal metabolism of APP and Abeta.
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Affiliation(s)
- Z Qiu
- Alzheimer Research Unit, Massachusetts General Hospital, Boston, MA 02129, USA
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