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Alexopoulos P, Thierjung N, Grimmer T, Ortner M, Economou P, Assimakopoulos K, Gourzis P, Politis A, Perneczky R. Cerebrospinal Fluid BACE1 Activity and sAβPPβ as Biomarker Candidates of Alzheimer's Disease. Dement Geriatr Cogn Disord 2018; 45:152-161. [PMID: 29788013 DOI: 10.1159/000488481] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/11/2018] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND/AIMS The utility of β-site amyloid-β precursor protein (AβPP) cleaving enzyme 1 (BACE1) activity and soluble AβPP β (sAβPPβ) levels in cerebrospinal fluid (CSF) in detecting Alzheimer's disease (AD) is still elusive. METHODS BACE1 activity and sAβPPβ concentration were measured in patients with AD dementia (n = 56) and mild cognitive impairment (MCI) due to AD (n = 76) with abnormal routine AD CSF markers, in patients with MCI with normal CSF markers (n = 39), and in controls without preclinical AD (n = 48). In a subsample with available 18F-fluorodeoxyglucose positron emission tomography (FDG PET) data, ordinal regression models were employed to compare the contribution of BACE1 and sAβPPβ to correct diagnostic classification to that of FDG PET. RESULTS BACE1 activity was significantly higher in patients with MCI due to AD compared to both controls and patients with MCI with normal CSF markers. sAβPPβ did not differ between any of the studied groups. Interestingly, BACE1 activity was not found to be inferior to FDG PET as predictive covariate in differentiating between the diagnostic groups. CONCLUSIONS Further studies using biomarker-underpinned diagnoses are warranted to shed more light on the potential diagnostic utility of BACE1 activity as AD biomarker candidate in MCI.
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Affiliation(s)
- Panagiotis Alexopoulos
- Department of Psychiatry, University Hospital of Rion, University of Patras, Patras, Greece.,Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Nathalie Thierjung
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Timo Grimmer
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Marion Ortner
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Polychronis Economou
- Department of Civil Engineering (Statistics), University of Patras, Patras, Greece
| | | | - Philippos Gourzis
- Department of Psychiatry, University Hospital of Rion, University of Patras, Patras, Greece
| | - Antonios Politis
- First Department of Psychiatry, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece.,Department of Psychiatry, Division of Geriatric Psychiatry and Neuropsychiatry, John's Hopkins Medical School, Baltimore, Maryland, USA
| | - Robert Perneczky
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-Universität München, Munich, Germany.,Neuroepidemiology and Ageing Research Unit, School of Public Health, Faculty of Medicine, The Imperial College of Science, Technology and Medicine, London, United Kingdom.,West London Mental Health NHS Trust, London, United Kingdom.,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
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Lopez-Font I, Boix CP, Zetterberg H, Blennow K, Sáez-Valero J. Alterations in the Balance of Amyloid-β Protein Precursor Species in the Cerebrospinal Fluid of Alzheimer's Disease Patients. J Alzheimers Dis 2018; 57:1281-1291. [PMID: 28372336 DOI: 10.3233/jad-161275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We recently demonstrated that soluble forms of the amyloid-β protein precursor (sAβPP) assemble into multimeric complexes in cerebrospinal fluid (CSF), which contributes to the underestimation of specific sAβPP species when assessed by ELISA. To circumvent this issue, we analyzed by SDS-PAGE large fragments of sAβPP and their variants in the CSF from Alzheimer's disease (AD; n = 20) and control (n = 20) subjects, probing with specific antibodies against particular domains. Similar levels of sAβPPα and sAβPPβ protein were found in CSF samples from AD and controls, yet there appeared to be a shift in the balance of the soluble full-length AβPP (sAβPPf) species in AD samples, with a decrease in the proportion of the lower (∼100 kDa) band relative to the upper (∼120 kDa) band. Similar differences were observed in the contribution of the major KPI-immunoreactive AβPP species. CSF samples also displayed differences in the correlations of AβPP species with classical AD biomarkers, particularly with respect to the Aβ42 peptide. The differences reveal alterations that probably reflect pathophysiological changes in the brain.
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Affiliation(s)
- Inmaculada Lopez-Font
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Claudia P Boix
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Inst. of Neuroscience and Physiology, University of Gothenburg, Mölndal Campus, Sweden.,Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Inst. of Neuroscience and Physiology, University of Gothenburg, Mölndal Campus, Sweden
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
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Savage MJ, Holder DJ, Wu G, Kaplow J, Siuciak JA, Potter WZ. Soluble BACE-1 Activity and sAβPPβ Concentrations in Alzheimer's Disease and Age-Matched Healthy Control Cerebrospinal Fluid from the Alzheimer's Disease Neuroimaging Initiative-1 Baseline Cohort. J Alzheimers Dis 2016; 46:431-40. [PMID: 25790831 DOI: 10.3233/jad-142778] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) plays an important role in the development of Alzheimer's disease (AD), freeing the amyloid-β (Aβ) N-terminus from the amyloid-β protein precursor (AβPP), the first step in Aβ formation. Increased BACE1 activity in AD brain or cerebrospinal fluid (CSF) has been reported. Other studies, however, found either no change or a decrease with AD diagnosis in either BACE1 activity or sAβPPβ, the N-terminal secreted product of BACE1 (sBACE1) activity on AβPP. Here, sBACE1 enzymatic activity and secreted AβPPβ (sAβPPβ) were measured in Alzheimer's Disease Neuroimaging Initiative-1 (ADNI-1) baseline CSF samples and no statistically significant changes were found in either measure comparing healthy control, mild cognitively impaired, or AD individual samples. While CSF sBACE1 activity and sAβPPβ demonstrated a moderate yet significant degree of correlation with each other, there was no correlation of either analyte to CSF Aβ peptide ending at residue 42. Surprisingly, a stronger correlation was demonstrated between CSF sBACE1 activity and tau, which was comparable to that between CSF Aβ₄₂ and tau. Unlike for these latter two analytes, receiver-operator characteristic curves demonstrate that neither CSF sBACE1 activity nor sAβPPβ concentrations can be used to differentiate between healthy elderly and AD individuals.
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Affiliation(s)
| | | | - Guoxin Wu
- Merck and Company, West Point, PA, USA
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Peters-Libeu C, Campagna J, Mitsumori M, Poksay KS, Spilman P, Sabogal A, Bredesen DE, John V. sAβPPα is a Potent Endogenous Inhibitor of BACE1. J Alzheimers Dis 2016; 47:545-55. [PMID: 26401691 DOI: 10.3233/jad-150282] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Proteolytic cleavage of the amyloid-β protein precursor (AβPP) by the enzyme BACE1 (BACE) is the initial step in production of amyloid-β peptide (Aβ), and as such has been a major target of Alzheimer's disease (AD) drug discovery efforts. Overproduction of Aβ results in neuronal cell death and accumulation of amyloid plaques in AD and in traumatic brain injury, and is also associated with stroke due to cerebral amyloid angiopathy. Herein we report for the first time that sAβPPα, the product of the cleavage of AβPP by α-secretase, is a potent endogenous direct inhibitor of the BACE enzyme, and that its inhibition is likely by an allosteric mechanism. Furthermore, using small-angle X-ray scattering, we show that sAβPPβ, which is identical to sAβPPα except for a 16-amino acid truncation at the carboxy terminus, adopts a completely different structure than sAβPPα and does not inhibit BACE. Our data thus reveal a novel mechanistic role played by sAβPPα in regulating overproduction of Aβ and restoring neuronal homeostasis and neuroprotection. Identification of sAβPPα as a direct BACE inhibitor may lead to design of new therapeutics targeting pathologies associated with overproduction of Aβ.
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Affiliation(s)
| | - Jesus Campagna
- Drug Discovery Laboratory, Department of Neurology, UCLA, Los Angeles, CA, USA
| | | | | | - Patricia Spilman
- Drug Discovery Laboratory, Department of Neurology, UCLA, Los Angeles, CA, USA
| | - Alex Sabogal
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Dale E Bredesen
- Buck Institute for Research on Aging, Novato, CA, USA.,Drug Discovery Laboratory, Department of Neurology, UCLA, Los Angeles, CA, USA.,Easton Center for Alzheimer's Disease Research, UCLA, Los Angeles, CA, USA
| | - Varghese John
- Buck Institute for Research on Aging, Novato, CA, USA.,Drug Discovery Laboratory, Department of Neurology, UCLA, Los Angeles, CA, USA.,Easton Center for Alzheimer's Disease Research, UCLA, Los Angeles, CA, USA
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