| 1. |
- Abramsson, Alexandra, 1973, et al.
(författare)
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Proteomics Profiling of Single Organs from Individual Adult Zebrafish.
- 2010
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Ingår i: Zebrafish. - : Mary Ann Liebert Inc. - 1557-8542 .- 1545-8547. ; 7:2, s. 161-168
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The model organism zebrafish (Danio rerio) is extensively utilized in studies of developmental biology but is also being investigated in the context of a growing list of human age-related diseases. To facilitate such studies, we here present protein expression patterns of adult zebrafish organs, including blood, brain, fin, heart, intestine, liver, and skeletal muscle. Protein extracts were prepared from the different organs of two zebrafish and analyzed using liquid chromatography coupled to high-resolution tandem mass spectrometry. Zebrafish tissue was digested directly after minimal fractionation and cleaned up (the shotgun approach). Proteins were identified using Mascot software. In total, 1394 proteins were identified of which 644 were nonredundant. Of these, 373 demonstrated an organ-specific expression pattern and 57 had not been shown on protein level before. These data emphasize the need for increased research at the protein level to facilitate the selection of candidate proteins for targeted quantification and to refine systematic genetic network analysis in vertebrate development, biology, and disease.
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| 2. |
- Brinkmalm, Gunnar, et al.
(författare)
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A Parallel Reaction Monitoring Mass Spectrometric Method for Analysis of Potential CSF Biomarkers for Alzheimer's Disease.
- 2018
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Ingår i: Proteomics. Clinical applications. - : Wiley. - 1862-8354 .- 1862-8346. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop and evaluate a parallel reaction monitoring mass spectrometry (PRM-MS) assay consisting of a panel of potential protein biomarkers in cerebrospinal fluid (CSF).Thirteen proteins were selected based on their association with neurodegenerative diseases and involvement in synaptic function, secretory vesicle function, or innate immune system. CSF samples were digested and two to three peptides per protein were quantified using stable isotope-labeled peptide standards.Coefficients of variation were generally below 15%. Clinical evaluation was performed on a cohort of 10 patients with Alzheimer's disease (AD) and 15 healthy subjects. Investigated proteins of the granin family exhibited the largest difference between the patient groups. Secretogranin-2 (p<0.005) and neurosecretory protein VGF (p<0.001) concentrations were lowered in AD. For chromogranin A, two of three peptides had significantly lowered AD concentrations (p<0.01). The concentrations of the synaptic proteins neurexin-1 and neuronal pentraxin-1, as well as neurofascin were also significantly lowered in AD (p<0.05). The other investigated proteins, β2-microglobulin, cystatin C, amyloid precursor protein, lysozyme C, neurexin-2, neurexin-3, and neurocan core protein, were not significantly altered.PRM-MS of protein panels is a valuable tool to evaluate biomarker candidates for neurodegenerative disorders.
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| 3. |
- Brinkmalm, Gunnar, et al.
(författare)
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An online nano-LC-ESI-FTICR-MS method for comprehensive characterization of endogenous fragments from amyloid β and amyloid precursor protein in human and cat cerebrospinal fluid.
- 2012
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Ingår i: Journal of mass spectrometry : JMS. - : Wiley. - 1096-9888 .- 1076-5174. ; 47:5, s. 591-603
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid precursor protein (APP) is the precursor protein to amyloid β (Aβ), the main constituent of senile plaques in Alzheimer's disease (AD). Endogenous Aβ peptides reflect the APP processing, and greater knowledge of different APP degradation pathways is important to understand the mechanism underlying AD pathology. When one analyzes longer Aβ peptides by low-energy collision-induced dissociation tandem mass spectrometry (MS/MS), mainly long b-fragments are observed, limiting the possibility to determine variations such as amino acid variants or post-translational modifications (PTMs) within the N-terminal half of the peptide. However, by using electron capture dissociation (ECD), we obtained a more comprehensive sequence coverage for several APP/Aβ peptide species, thus enabling a deeper characterization of possible variants and PTMs. Abnormal APP/Aβ processing has also been described in the lysosomal storage disease Niemann-Pick type C and the major large animal used for studying this disease is cat. By ECD MS/MS, a substitution of Asp7 → Glu in cat Aβ was identified. Further, sialylated core 1 like O-glycans at Tyr10, recently discovered in human Aβ (a previously unknown glycosylation type), were identified also in cat cerebrospinal fluid (CSF). It is therefore likely that this unusual type of glycosylation is common for (at least) species belonging to the magnorder Boreoeutheria. We here describe a detailed characterization of endogenous APP/Aβ peptide species in CSF by using an online top-down MS-based method.
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| 4. |
- Brinkmalm, Gunnar, et al.
(författare)
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Soluble amyloid precursor protein alpha and beta in CSF in Alzheimer's disease
- 2013
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Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1513, s. 117-126
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Cerebral accumulation of amyloid beta (A beta) is a pathological hallmark of Alzheimer's disease (AD). Proteolytic processing of amyloid precursor protein (APP) by alpha- or beta-secretase results in two soluble metabolites, sAPP alpha and sAPP beta, respectively. However, previous data have shown that both alpha- and beta-secretase have multiple cleavage sites. The aim of this study was to characterize the C-termini of sAPP alpha and sAPP beta in cerebrospinal fluid (CSF) by mass spectrometry (MS) and to evaluate whether different combinations of these fragments better separate between AD patients and controls by comparing two different sAPP immunoassays. Methods: Using immunoprecipitation and high resolution MS, the APP species present in CSF were investigated. CSF levels of sAPP alpha and sAPP beta from patients with AD (n=43) and from non-demented controls (n=44) were measured using AlphaLISA and MSD immunoassays that employ different antibodies for C-terminal recognition of sAPP alpha. Results: Four different C-terminal forms of sAPP were identified, sAPP beta-M671, sAPP beta-Y681, sAPP alpha-Q686, and 5APP alpha-K687 (APP770 numbering). Neither immunoassay for the sAPP species could separate the two patient groups. The correlation (R-2) between the two immunoassays was 0.41 for sAPP alpha and 0.45 for sAPP beta. Conclusion: Using high resolution MS, we show here for the first time that sAPP alpha in CSF ends at Q686 and K687. The findings also support the conclusion from several previous studies that sAPP alpha and sAPP beta levels are unaltered in AD. (C) 2013 Elsevier B.V. All rights reserved.
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| 5. |
- Brinkmalm, Gunnar, et al.
(författare)
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Soluble amyloid precursor protein α and β in CSF in Alzheimer's disease.
- 2013
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Ingår i: Brain research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1513, s. 117-26
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral accumulation of amyloid β (Aβ) is a pathological hallmark of Alzheimer's disease (AD). Proteolytic processing of amyloid precursor protein (APP) by α- or β-secretase results in two soluble metabolites, sAPPα and sAPPβ, respectively. However, previous data have shown that both α- and β-secretase have multiple cleavage sites. The aim of this study was to characterize the C-termini of sAPPα and sAPPβ in cerebrospinal fluid (CSF) by mass spectrometry (MS) and to evaluate whether different combinations of these fragments better separate between AD patients and controls by comparing two different sAPP immunoassays. Methods: Using immunoprecipitation and high resolution MS, the APP species present in CSF were investigated. CSF levels of sAPPα and sAPPβ from patients with AD (n=43) and from non-demented controls (n=44) were measured using AlphaLISA and MSD immunoassays that employ different antibodies for C-terminal recognition of sAPPα. Results: Four different C-terminal forms of sAPP were identified, sAPPβ-M671, sAPPβ-Y681, sAPPα-Q686, and sAPPα-K687 (APP770 numbering). Neither immunoassay for the sAPP species could separate the two patient groups. The correlation (R(2)) between the two immunoassays was 0.41 for sAPPα and 0.45 for sAPPβ. Conclusion: Using high resolution MS, we show here for the first time that sAPPα in CSF ends at Q686 and K687. The findings also support the conclusion from several previous studies that sAPPα and sAPPβ levels are unaltered in AD.
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| 6. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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A Mass Spectrometer´s Building Blocks
- 2009
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Ingår i: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 15-87
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter contains sections titled: * Ion Sources * Mass Analyzers * Detectors * References
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| 7. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Definitions and Explanations
- 2009
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Ingår i: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 3-13
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
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| 8. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
-
Explorative and targeted neuroproteomics in Alzheimer's disease.
- 2015
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Ingår i: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1854:7, s. 769-778
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is a progressive brain amyloidosis that injures brain regions involved in memory consolidation and other higher brain functions. Neuropathologically, the disease is characterized by accumulation of a 42 amino acid peptide called amyloid β (Aβ42) in extracellular senile plaques, intraneuronal inclusions of hyperphosphorylated tau protein in neurofibrillary tangles, and neuronal and axonal degeneration and loss. Biomarker assays capturing these pathologies have been developed for use on cerebrospinal fluid samples but there are additional molecular pathways that most likely contribute to the neurodegeneration and full clinical expression of AD. One way of learning more about AD pathogenesis is to identify novel biomarkers for these pathways and examine them in longitudinal studies of patients in different stages of the disease. Here, we discuss targeted proteomic approaches to study AD and AD-related pathologies in closer detail and explorative approaches to discover novel pathways that may contribute to the disease. This article is part of a Special Issue entitled: Neuroproteomics: Applications in neuroscience and neurology.
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| 9. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Fluid-based proteomics targeted on pathophysiological processes and pathologies in neurodegenerative diseases.
- 2019
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Ingår i: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 151:4, s. 417-434
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Tidskriftsartikel (refereegranskat)abstract
- Neurodegenerative dementias constitute a broad group of diseases in which abnormally folded proteins accumulate in specific brain regions and result in tissue reactions that eventually cause neuronal dysfunction and degeneration. Depending on where in the brain this happens, symptoms appear which may be used to classify the disorders on clinical grounds. However, brain changes in neurodegenerative dementias start to accumulate many years prior to symptom onset and there is a poor correlation between the clinical picture and what pathology that is the most likely to cause it. Thus, novel drug candidates having disease-modifying effects that is targeting the underlying pathology and changes the course of the disease needs to be defined using objective biomarker-based measures since the clinical symptoms are often non-specific and overlap between different disorders. Furthermore, the treatment should ideally be initiated as soon as symptoms are evident or when biomarkers confirm an underlying pathology (pre-clinical phase of the disease) to reduce irreversible damage to, for example, neurons, synapses and axons. Clinical trials in the pre-clinical phase bring a greater importance to biomarkers since by definition the clinical effects are difficult or slow to discern in a population that is not yet clinically affected. Here, we discuss neuropathological changes that may underlie neurodegenerative dementias, including how they can be detected and quantified using currently available biofluid-based biomarkers and how more of them could be identified using targeted proteomics approaches.
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| 10. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Proteomics/peptidomics tools to find CSF biomarkers for neurodegenerative diseases.
- 2009
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Ingår i: Frontiers in bioscience : a journal and virtual library. - : IMR Press. - 1093-4715. ; 14, s. 1793-806
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Forskningsöversikt (refereegranskat)abstract
- Neurodegenerative diseases are characterized by premature neuronal loss in specific brain regions. During the past decades our knowledge on molecular mechanisms underlying neurodegeneration has increased immensely and resulted in promising drug candidates that might slow down or even stop the neuronal loss. These advances have put a strong focus on the development of diagnostic tools for early or pre-clinical detection of the disorders. In this review we discuss our experience in the field of neuroproteomics/peptidomics, with special focus on biomarker discovery studies that have been performed on CSF samples from well-defined patient and control populations.
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| 11. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Separation Methods
- 2009
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Ingår i: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 105-115
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter contains sections titled: * Chromatography * Electric-Field Driven Separations * References
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| 12. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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SILAC zebrafish for quantitative analysis of protein turnover and tissue regeneration.
- 2011
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Ingår i: Journal of proteomics. - : Elsevier BV. - 1876-7737 .- 1874-3919. ; 75:2, s. 425-34
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Tidskriftsartikel (refereegranskat)abstract
- Defective tissue regeneration is thought to contribute to several human diseases, including neurodegenerative disorders, heart failure and various lung diseases. Boosting the regenerative capacity has been suggested a possible therapeutic approach. Methods to metabolically label newly synthesized proteins in vivo with stable isotopic forms of amino acids holds promise for the study of protein turnover and tissue regeneration that are fundamental to the sustained life of all organisms. Here, we used the "stable isotope labeling with amino acids in cell culture" (SILAC) approach to explore normal protein turnover and tissue regeneration in adult zebrafish. The ratio of labeled and unlabeled proteins/peptides in specific organs of zebrafish fed a SILAC diet containing (13)C(6)-labeled lysine was determined by liquid chromatography and tandem mass spectrometry. Labeling was highest in tissues with high regenerative capacity, including intestine, liver, and fin, whereas brain and heart displayed the lowest labeling. Proteins with high degree of labeling were mainly involved in catalytic or transport activity pathways. The technique also verified increased protein synthesis during regeneration of the caudal fin following amputation. This newly developed SILAC zebrafish model constitutes a novel tool to analyze tissue regeneration in an animal model amenable to genetic and pharmacologic manipulation.
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| 13. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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SNAP-25 is a promising novel cerebrospinal fluid biomarker for synapse degeneration in Alzheimer's disease
- 2014
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Ingår i: Molecular Neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Synaptic degeneration is an early pathogenic event in Alzheimer's disease, associated with cognitive impairment and disease progression. Cerebrospinal fluid biomarkers reflecting synaptic integrity would be highly valuable tools to monitor synaptic degeneration directly in patients. We previously showed that synaptic proteins such as synaptotagmin and synaptosomal-associated protein 25 (SNAP-25) could be detected in pooled samples of cerebrospinal fluid, however these assays were not sensitive enough for individual samples. Results: We report a new strategy to study synaptic pathology by using affinity purification and mass spectrometry to measure the levels of the presynaptic protein SNAP-25 in cerebrospinal fluid. By applying this novel affinity mass spectrometry strategy on three separate cohorts of patients, the value of SNAP-25 as a cerebrospinal fluid biomarker for synaptic integrity in Alzheimer's disease was assessed for the first time. We found significantly higher levels of cerebrospinal fluid SNAP-25 fragments in Alzheimer's disease, even in the very early stages, in three separate cohorts. Cerebrospinal fluid SNAP-25 differentiated Alzheimer's disease from controls with area under the curve of 0.901 (P < 0.0001). Conclusions: We developed a sensitive method to analyze SNAP-25 levels in individual CSF samples that to our knowledge was not possible previously. Our results support the notion that synaptic biomarkers may be important tools for early diagnosis, assessment of disease progression, and to monitor drug effects in treatment trials.
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| 14. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Tandem Mass Spectrometry
- 2009
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Ingår i: Mass Spectrometry: Instrumentation, Interpretation, and Applications. Eds. Rolf Ekman, Jerzy Silberring, Ann Westman-Brinkmalm, Agnieszka Kraj. - New York : Wiley. - 9780471713951 ; , s. 89-103
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter contains sections titled: * Tandem MS Analyzer Combinations * Ion Activation Methods * References
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| 15. |
- Brinkmalm-Westman, Ann, 1966, et al.
(författare)
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Targeting synaptic pathology with a novel affinity mass spectrometry approach.
- 2014
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Ingår i: Molecular & cellular proteomics : MCP. - 1535-9484. ; 13:10, s. 2584-92
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel strategy for studying synaptic pathology by concurrently measuring levels of four SNARE complex proteins from individual brain tissue samples. This method combines affinity purification and mass spectrometry and can be applied directly for studies of SNARE complex proteins in multiple species or modified to target other key elements in neuronal function. We use the technique to demonstrate altered levels of presynaptic proteins in Alzheimer disease patients and prion-infected mice.
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| 16. |
- Camporesi, Elena, et al.
(författare)
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Quantification of the trans-synaptic partners neurexin-neuroligin in CSF of neurodegenerative diseases by parallel reaction monitoring mass spectrometry
- 2022
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Ingår i: Ebiomedicine. - : Elsevier BV. - 2352-3964. ; 75
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Tidskriftsartikel (refereegranskat)abstract
- Background: Synaptic proteins are increasingly studied as biomarkers for synaptic dysfunction and loss, which are early and central events in Alzheimer's disease (AD) and strongly correlate with the degree of cognitive decline. In this study, we specifically investigated the synaptic binding partners neurexin (NRXN) and neuroligin (Nlgn) proteins, to assess their biomarker's potential. Methods: we developed a parallel reaction monitoring mass spectrometric method for the simultaneous quantification of NRXNs and Nlgns in cerebrospinal fluid (CSF) of neurodegenerative diseases, focusing on AD. Specifically, NRXN-1α, NRXN-1β, NRXN-2α, NRXN-3α and Nlgn1, Nlgn2, Nlgn3 and Nlgn4 proteins were targeted. Findings: The proteins were investigated in a clinical cohort including CSF from controls (n=22), mild cognitive impairment (MCI) due to AD (n=44), MCI due to other conditions (n=46), AD (n=77) and a group of non-AD dementia (n=28). No difference in levels of NRXNs and Nlgns was found between AD (both at dementia and MCI stages) or controls or the non-AD dementia group for any of the targeted proteins. NRXN and Nlgn proteins correlated strongly with each other, but only a weak correlation with the AD core biomarkers and the synaptic biomarkers neurogranin and growth-associated protein 43, was found, possibly reflecting different pathogenic processing at the synapse. Interpretation: we conclude that NRXN and Nlgn proteins do not represent suitable biomarkers for synaptic pathology in AD. The panel developed here could aid in future investigations of the potential involvement of NRXNs and Nlgns in synaptic dysfunction in other disorders of the central nervous system. Funding: a full list of funding can be found under the acknowledgments section. © 2021 The Author(s)
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| 17. |
- Duits, F. H., et al.
(författare)
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Synaptic proteins in CSF as potential novel biomarkers for prognosis in prodromal Alzheimer's disease
- 2018
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background: We investigated whether a panel of 12 potential novel biomarkers consisting of proteins involved in synapse functioning and immunity would be able to distinguish patients with Alzheimer's disease (AD) and patients with mild cognitive impairment (MCI) from control subjects. Methods: We included 40 control subjects, 40 subjects with MCI, and 40 subjects with AD from the Amsterdam Dementia Cohort who were matched for age and sex (age 65 +/- 5 years, 19 [48%] women). The mean follow-up of patients with MCI was 3 years. Two or three tryptic peptides per protein were analyzed in cerebrospinal fluid using parallel reaction monitoring mass spectrometry. Corresponding stable isotope-labeled peptides were added and used as reference peptides. Multilevel generalized estimating equations (GEEs) with peptides clustered per subject and per protein (as within-subject variables) were used to assess differences between diagnostic groups. To assess differential effects of individual proteins, we included the diagnosis x protein interaction in the model. Separate GEE analyses were performed to assess differences between stable patients and patients with progressive MCI (MCI-AD). Results: There was a main effect for diagnosis (p < 0.01) and an interaction between diagnosis and protein (p < 0.01). Analysis stratified according to protein showed higher levels in patients with MCI for most proteins, especially in patients with MCI-AD. Chromogranin A, secretogranin II, neurexin 3, and neuropentraxin 1 showed the largest effect sizes; beta values ranged from 0.53 to 0.78 for patients with MCI versus control subjects or patients with AD, and from 0.67 to 0.98 for patients with MCI-AD versus patients with stable MCI. In contrast, neurosecretory protein VGF was lower in patients with AD than in patients with MCI (beta = -0.93 [SE 0.22]) and control subjects (beta = 0.46 [SE 0.19]). Conclusions: Our results suggest that several proteins involved in vesicular transport and synaptic stability are elevated in patients with MCI, especially in patients with MCI progressing to AD dementia. This may reflect early events in the AD pathophysiological cascade. These proteins may be valuable as disease stage or prognostic markers in an early symptomatic stage of the disease.
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| 18. |
- Gkanatsiou, Eleni, et al.
(författare)
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Amyloid pathology and synaptic loss in pathological aging
- 2021
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Ingår i: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 159:2, s. 258-272
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive memory dysfunction and cognitive decline. Pathological aging (PA) describes patients who are amyloid-positive but cognitively unimpaired at time of death. Both AD and PA contain amyloid plaques dominated by amyloid beta (A beta) peptides. In this study, we investigated and compared synaptic protein levels, amyloid plaque load, and A beta peptide patterns between AD and PA. Two cohorts of post-mortem brain tissue were investigated. In the first, consisting of controls, PA, AD, and familial AD (FAD) individuals, synaptic proteins extracted with tris(hydroxymethyl)aminomethane-buffered saline (TBS) were analyzed. In the second, consisting of tissue from AD and PA patients from three different regions (occipital lobe, frontal lobe, and cerebellum), a two-step extraction was performed. Five synaptic proteins were extracted using TBS, and from the remaining portion A beta peptides were extracted using formic acid. Subsequently, immunoprecipitation with several antibodies targeting different proteins/peptides was performed for both fractions, which were subsequently analyzed by mass spectrometry. The levels of synaptic proteins were lower in AD (and FAD) compared with PA (and controls), confirming synaptic loss in AD patients. The amyloid plaque load was increased in AD compared with PA, and the relative amount of A beta 40 was higher in AD while for A beta 42 it was higher in PA. In AD loss of synaptic function was associated with increased plaque load and increased amounts of A beta 40 compared with PA cases, suggesting that synaptic function is preserved in PA cases even in the presence of A beta.
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| 19. |
- Gobom, Johan, et al.
(författare)
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Alzheimer's Disease Biomarker Analysis Using Targeted Mass Spectrometry.
- 2024
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Ingår i: Molecular & cellular proteomics : MCP. - 1535-9484. ; 23:2
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is characterized by several neuropathological changes, mainly extracellular amyloid aggregates (plaques), intraneuronal inclusions of phosphorylated tau (tangles), as well as neuronal and synaptic degeneration, accompanied by tissue reactions to these processes (astrocytosis and microglial activation) that precede neuronal network disturbances in the symptomatic phase of the disease. A number of biomarkers for these brain tissue changes have been developed, mainly using immunoassays. In this review, we discuss how targeted mass spectrometry (TMS) can be used to validate and further characterize classes of biomarkers reflecting different AD pathologies, such as tau- and amyloid-beta pathologies, synaptic dysfunction, lysosomal dysregulation, and axonal damage, and the prospect of using TMS to measure these proteins in clinical research and diagnosis. TMS advantages and disadvantages in relation to immunoassays are discussed, and complementary aspects of the technologies are discussed.
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| 20. |
- Halim, Adnan, et al.
(författare)
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Site-specific characterization of threonine, serine, and tyrosine glycosylations of amyloid precursor protein/amyloid {beta}-peptides in human cerebrospinal fluid.
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 108:29, s. 11848-53
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Tidskriftsartikel (refereegranskat)abstract
- The proteolytic processing of human amyloid precursor protein (APP) into shorter aggregating amyloid β (Aβ)-peptides, e.g., Aβ1-42, is considered a critical step in the pathogenesis of Alzheimer's disease (AD). Although APP is a well-known membrane glycoprotein carrying both N- and O-glycans, nothing is known about the occurrence of released APP/Aβ glycopeptides in cerebrospinal fluid (CSF). We used the 6E10 antibody and immunopurified Aβ peptides and glycopeptides from CSF samples and then liquid chromatography-tandem mass spectrometry for structural analysis using collision-induced dissociation and electron capture dissociation. In addition to 33 unglycosylated APP/Aβ peptides, we identified 37 APP/Aβ glycopeptides with sialylated core 1 like O-glycans attached to Thr(-39, -21, -20, and -13), in a series of APP/AβX-15 glycopeptides, where X was -63, -57, -52, and -45, in relation to Asp1 of the Aβ sequence. Unexpectedly, we also identified a series of 27 glycopeptides, the Aβ1-X series, where X was 20 (DAEFRHDSGYEVHHQKLVFF), 19, 18, 17, 16, and 15, which were all uniquely glycosylated on Tyr10. The Tyr10 linked O-glycans were (Neu5Ac)(1-2)Hex(Neu5Ac)HexNAc-O- structures with the disialylated terminals occasionally O-acetylated or lactonized, indicating a terminal Neu5Acα2,8Neu5Ac linkage. We could not detect any glycosylation of the Aβ1-38/40/42 isoforms. We observed an increase of up to 2.5 times of Tyr10 glycosylated Aβ peptides in CSF in six AD patients compared to seven non-AD patients. APP/Aβ sialylated O-glycans, including that of a Tyr residue, the first in a mammalian protein, may modulate APP processing, inhibiting the amyloidogenic pathway associated with AD.
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| 21. |
- Johansson, Kalle, et al.
(författare)
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Cerebrospinal fluid amyloid precursor protein as a potential biomarker of fatigue in multiple sclerosis: A pilot study
- 2022
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Ingår i: Multiple Sclerosis and Related Disorders. - : Elsevier BV. - 2211-0348. ; 63
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Tidskriftsartikel (refereegranskat)abstract
- Background: Fatigue is the major cause of disability in MS. Fatigue has been suggested to be primary, part of the neurological disease; it can also be secondary to other diseases outside the CNS or exist as a separate comorbidity. The only forms of measurement currently available are through subjective standardized questionnaires, which are not able to identify primary MS-related fatigue. Therefore, there is a need for objective biomarkers of fatigue in MS. This study explored the viability of 17 possible biomarkers of primary fatigue in MS. Our chosen biomarker panel represents the function and health of different parts of the CNS. Methods: We evaluated 31 MS patients and 17 healthy controls using the Fatigue Severity Scale (FSS) and Insomnia Severity Index (ISI). We assessed clinical parameters and collected CSF from all participants to analyze 17 biomarkers, some of which in multiple targeted sequences, reflecting structural and functional changes in the brain. Based on FSS scores, MS was divided into MS-Fatigue (MS-F, FSS >= 4) and MS-NoFatigue (MS-NoF, FSS < 4). Results: MS-F had significantly lower levels of amyloid precursor protein (APP) peptides than MS-NoF (p = 0.005, p = 0.011). The only biomarker correlating with FSS in any group was APP in MS (r = -0.47, -0.52; p = 0.007, 0.002). APP did not correlate with any clinical parameter in MS but correlated with multiple markers. In MS, FSS correlated with the ISI and months since diagnosis. Conclusion: Although the mechanisms remain unknown, altered APP metabolism in MS seems to be associated with fatigue. APP should be evaluated as a biomarker of the role of structural MS pathology in the development of fatigue in individual MS patients.
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| 22. |
- Lantero Rodriguez, Juan, et al.
(författare)
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Tau protein profiling in tauopathies: a human brain study
- 2024
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Ingår i: MOLECULAR NEURODEGENERATION. - 1750-1326. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal accumulation of misfolded and hyperphosphorylated tau protein in brain is the defining feature of several neurodegenerative diseases called tauopathies, including Alzheimer's disease (AD). In AD, this pathological change is reflected by highly specific cerebrospinal fluid (CSF) tau biomarkers, including both phosphorylated and non-phosphorylated variants. Interestingly, despite tau pathology being at the core of all tauopathies, CSF tau biomarkers remain unchanged in certain tauopathies, e.g., progressive supranuclear palsy (PSP), Pick's disease (PiD), and corticobasal neurodegeneration (CBD). To better understand commonalities and differences between tauopathies, we report a multiplex assay combining immunoprecipitation and high-resolution mass spectrometry capable of detecting and quantifying peptides from different tau protein isoforms as well as non-phosphorylated and phosphorylated peptides, including those carrying multiple phosphorylations. We investigated the tau proteoforms in soluble and insoluble fractions of brain tissue from subjects with autopsy-confirmed tauopathies, including sporadic AD (n = 10), PSP (n = 11), PiD (n = 10), and CBD (n = 10), and controls (n = 10). Our results demonstrate that non-phosphorylated tau profiles differ across tauopathies, generally showing high abundance of microtubule-binding region (MTBR)-containing peptides in insoluble protein fractions compared with controls; the AD group showed 12-72 times higher levels of MTBR-containing aggregates. Quantification of tau isoforms showed the 3R being more abundant in PiD and the 4R isoform being more abundant in CBD and PSP in the insoluble fraction. Twenty-three different phosphorylated peptides were quantified. Most phosphorylated peptides were measurable in all investigated tauopathies. All phosphorylated peptides were significantly increased in AD insoluble fraction. However, doubly and triply phosphorylated peptides were significantly increased in AD even in the soluble fraction. Results were replicated using a validation cohort comprising AD (n = 10), CBD (n = 10), and controls (n = 10). Our study demonstrates that abnormal levels of phosphorylation and aggregation do indeed occur in non-AD tauopathies, however, both appear pronouncedly increased in AD, becoming a distinctive characteristic of AD pathology.
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| 23. |
- Nilsson, Johanna, 1993, et al.
(författare)
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Cerebrospinal fluid biomarker panel for synaptic dysfunction in Alzheimer's disease
- 2021
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Ingår i: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring. - : Wiley. - 2352-8729. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Synaptic dysfunction and degeneration is one of the earliest events in Alzheimer's disease (AD) and the best correlate of cognitive decline. Thus, identification and validation of biomarkers reflecting synaptic degeneration to be used as prognostic biomarkers are greatly needed. Method Solid-phase extraction and parallel reaction monitoring mass spectrometry were used to quantify 17 synaptic proteins in CSF, in two cross-sectional studies including AD (n = 52) and controls (n = 37). Results Increased concentrations of beta-synuclein, gamma-synuclein, neurogranin, phosphatidylethanolamine-binding protein 1, and 14-3-3 proteins were observed in AD patients compared to controls, while neuronal pentraxin-2 and neuronal pentraxin receptor were decreased. Discussion We have established a method with a novel panel of synaptic proteins as biomarkers of synaptic dysfunction. The results indicate that several of the proteins included in the panel may serve as synaptic biomarkers for AD.
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| 24. |
- Portelius, Erik, 1977, et al.
(författare)
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A novel pathway for amyloid precursor protein processing.
- 2011
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Ingår i: Neurobiology of aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 32:6, s. 1090-98
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid precursor protein (APP) can be proteolytically processed along two pathways, the amyloidogenic that leads to the formation of the 40-42 amino acid long Alzheimer-associated amyloid beta (Abeta) peptide and the non-amyloidogenic in which APP is cut in the middle of the Abeta domain thus precluding Abeta formation. Using immunoprecipitation and mass spectrometry we have shown that Abeta is present in cerebrospinal fluid (CSF) as several shorter isoforms in addition to Abeta1-40 and Abeta1-42. To address the question by which processing pathways these shorter isoforms arise, we have developed a cell model that accurately reflects the Abeta isoform pattern in CSF. Using this model, we determined changes in the Abeta isoform pattern induced by alpha-, beta-, and gamma-secretase inhibitor treatment. All isoforms longer than and including Abeta1-17 were gamma-secretase dependent whereas shorter isoforms were gamma-secretase independent. These shorter isoforms, including Abeta1-14 and Abeta1-15, were reduced by treatment with alpha- and beta-secretase inhibitors, which suggests the existence of a third and previously unknown APP processing pathway involving concerted cleavages of APP by alpha- and beta-secretase.
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| 25. |
- Portelius, Erik, 1977, et al.
(författare)
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An Alzheimer's disease-specific beta-amyloid fragment signature in cerebrospinal fluid.
- 2006
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Ingår i: Neuroscience letters. - : Elsevier BV. - 0304-3940. ; 409:3, s. 215-9
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic events in Alzheimer's disease (AD) involve an imbalance between the production and clearance of the neurotoxic beta-amyloid peptide (Abeta), especially the 42 amino acid peptide Abeta1-42. While much is known about the production of Abeta1-42, many questions remain about how the peptide is degraded. To investigate the degradation pattern, we developed a method based on immunoprecipitation combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry that determines the Abeta degradation fragment pattern in cerebrospinal fluid (CSF). We found in total 18 C-terminally and 2 N-terminally truncated Abeta peptides and preliminary data indicated that there were differences in the detected Abeta relative abundance pattern between AD and healthy controls. Here, we provide direct evidence that an Abeta fragment signature consisting of Abeta1-16, Abeta1-33, Abeta1-39, and Abeta1-42 in CSF distinguishes sporadic AD patients from non-demented controls with an overall accuracy of 86%.
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| 26. |
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| 27. |
- Portelius, Erik, 1977, et al.
(författare)
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Characterization of tau in cerebrospinal fluid using mass spectrometry.
- 2008
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Ingår i: Journal of proteome research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 7:5, s. 2114-20
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Tidskriftsartikel (refereegranskat)abstract
- The neurodegenerative disorder Alzheimer's disease (AD) is the most common cause of dementia in the elderly. The presence of neurofibrillary tangles, consisting of hyperphosphorylated tau protein, is one of the major neuropathologic characteristics of the disease, making this protein an attractive biomarker for AD and a possible target for therapy. Here, we describe an optimized immunoprecipitation mass spectrometry method that enables, for the first time, detailed characterization of tau in human cerebrospinal fluid. The identities of putative tau fragments were confirmed using nanoflow liquid chromatography and tandem mass spectrometry. Nineteen tryptic fragments of tau were detected, of which 16 are found in all tau isoforms while 3 represented unique tau isoforms. These results pave the way for clinical CSF studies on the tauopathies.
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| 28. |
- Portelius, Erik, 1977, et al.
(författare)
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Effects of gamma-Secretase Inhibition on the Amyloid beta Isoform Pattern in a Mouse Model of Alzheimer's Disease.
- 2009
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Ingår i: Neuro-degenerative diseases. - : S. Karger AG. - 1660-2862 .- 1660-2854. ; 6:5-6
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Tidskriftsartikel (refereegranskat)abstract
- Background:Accumulation of amyloid beta (Abeta) in the brain is believed to represent one of the earliest events in the Alzheimer disease process. Abeta is generated from amyloid precursor protein after sequential cleavage by beta- and gamma-secretase. Alternatively, alpha-secretase cleaves within the Abeta sequence, thus, precluding the formation of Abeta. A lot of research has focused on Abeta production, while less is known about the non-amyloidogenic pathway. We have previously shown that Abeta is present in human cerebrospinal fluid (CSF) as several shorter C-terminal truncated isoforms (e.g. Abeta1-15 and Abeta1-16), and that the levels of these shorter isoforms are elevated in media from cells that have been treated with gamma-secretase inhibitors. Objective:To explore the effect of N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT), a gamma-secretase-inhibitor, treatment on the Abeta isoform pattern in brain tissue and CSF from Tg2576 mice. Methods: Immunoprecipitation using the anti-Abeta antibodies 6E10 and 4G8 was combined with either matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or nanoflow liquid chromatography and tandem mass spectrometry. Results: All fragments longer than and including Abeta1-17 displayed a tendency towards decreased levels upon gamma-secretase inhibition, whereas Abeta1-15 and Abeta1-16 indicated slightly elevated levels during treatment. Conclusion: These data suggest that Abeta1-15 and Abeta1-16 may be generated through a third metabolic pathway independent of gamma-secretase, and that these Abeta isoforms may serve as biomarkers for secretase inhibitor treatment.
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| 29. |
- Portelius, Erik, 1977, et al.
(författare)
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Identification of novel APP/Abeta isoforms in human cerebrospinal fluid.
- 2009
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Ingår i: Neuro-degenerative diseases. - : S. Karger AG. - 1660-2862 .- 1660-2854. ; 6:3, s. 87-94
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Aggregation of beta-amyloid (Abeta) into oligomers and plaques is the central pathogenic mechanism in Alzheimer's disease (AD). Abeta is produced from the amyloid precursor protein (APP) by beta- and gamma-secretases, whereas, in the nonamyloidogenic pathway, alpha-secretase cleaves within the Abeta sequence, and thus precludes Abeta formation. A lot of research has focused on Abeta production and the neurotoxic 42-amino-acid form of Abeta (Abeta1-42), while less is known about the nonamyloidogenic pathway and how Abeta is degraded. OBJECTIVE: To study the Abeta metabolism in man by searching for novel Abeta peptides in cerebrospinal fluid (CSF). METHODS: Immunoprecipitation, using an anti-Abeta antibody, 6E10, was combined with either matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or nanoflow liquid chromatography and tandem mass spectrometry. RESULTS: We identified 12 truncated APP/Abeta peptides in the CSF, all of which end at amino acid 15 in the Abeta sequence, i.e. 1 amino acid before the proposed alpha-secretase site. Of these 12 APP/Abeta peptides, 11 are novel peptides and start N-terminally of the beta-secretase site. The most abundant APP/Abeta peptide starts 25 amino acids before the beta-secretase site, APP/Abeta (-25 to 15), and had a concentration of approximately 80 pg/ml. The identity of all the APP/Abeta peptides was verified in a cohort of AD patients and controls. A first pilot study also showed that the intensity of several APP/Abeta peaks in CSF was higher in AD cases than in controls. CONCLUSION: These data suggest an enzymatic activity that cleaves the precursor protein in a specific manner that may reflect a novel metabolic pathway for APP and Abeta.
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| 30. |
- Portelius, Erik, 1977, et al.
(författare)
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Identification of novel N-terminal fragments of amyloid precursor protein in cerebrospinal fluid.
- 2010
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Ingår i: Experimental neurology. - : Elsevier BV. - 1090-2430 .- 0014-4886. ; 223:2, s. 351-358
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is a progressive neurodegenerative disorder of the central nervous system. Two pathological hallmarks in the brain of AD patients are neurofibrillary tangles and senile plaques. The plaques consist mainly of beta-amyloid (Abeta) peptides that are produced from the amyloid precursor protein (APP), by sequential cleavage by beta- and gamma-secretase. Most previous studies have been focused on the C-terminal fragments of APP, where the Abeta sequence is localized. The purpose of this study was to search for N-terminal fragments of APP in cerebrospinal fluid (CSF) using mass spectrometry (MS). By using immunoprecipitation (IP) combined with matrix-assisted laser desorption/ionization time-of-flight MS as well as nanoflow liquid chromatography coupled to high resolution tandem MS we were able to detect and identify six novel N-terminal APP fragments [APP((18-119)), APP((18-121)), APP((18-122)), APP((18-123)), APP((18-124)) and APP((18-126))], having molecular masses of approximately 12 kDa. The presence of these APP derivatives in CSF was also verified by Western blot analysis. Two pilot studies using either IP-MS or Western blot analysis indicated slightly elevated levels of N-terminal APP fragments in CSF from AD patients compared with controls, which are in need of replications in independent and larger patient materials.
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| 31. |
- Portelius, Erik, 1977, et al.
(författare)
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Mass spectrometric characterization of amyloid-β species in the 7PA2 cell model of Alzheimer's disease.
- 2013
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Ingår i: Journal of Alzheimer's disease : JAD. - 1875-8908. ; 33:1, s. 85-93
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Tidskriftsartikel (refereegranskat)abstract
- The Chinese hamster ovary cell line 7PA2, stably transfected with the 751 amino acid isoform of amyloid-β protein precursor (AβPP) containing the Val → Phe mutation at residue 717, is one of the most used models to study the biochemistry and toxicity of secreted amyloid-β (Aβ) peptides, particularly Aβ oligomers, which are considered to be of relevance to the pathogenesis of Alzheimer's disease. Here, we present a detailed immunochemical and mass spectrometric characterization of primary structures of Aβ peptides secreted by 7PA2 cells. Immunoprecipitation and western blot of 7PA2 cell culture media revealed abundant anti-Aβ immunoreactive bands in the molecular weight range of 4-20 kDa. Mass spectrometric analysis showed that these bands contain several AβPP/Aβ peptides, starting at the N-terminal of the Aβ sequence and extending across the BACE1 cleavage site. Treatment of cells with a BACE1 inhibitor decreased the abundance of the Aβ monomer band by western blot and resulted in lower levels of Aβ1-40, Aβ1-42, and sAβPPβ as measured by ELISA. However, western blot bands thought to represent oligomers of Aβ increased in response to BACE1 inhibition. This increase was paralleled by the emergence of N-terminally truncated Aβ species (Aβ5-40 in particular) and Aβ species that spanned the β-secretase site in AβPP according to mass spectrometric analyses. The formation of these AβPP/Aβ peptides may have implications for the use of the 7PA2 cell line as a model for Aβ pathology. The enzyme(s) responsible for this particular BACE1-independent AβPP-processing remains to be identified.
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| 32. |
- Portelius, Erik, 1977, et al.
(författare)
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Proteomic studies of cerebrospinal fluid biomarkers of Alzheimer's disease: an update.
- 2017
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Ingår i: Expert review of proteomics. - : Informa UK Limited. - 1744-8387 .- 1478-9450. ; 14:11, s. 1007-1020
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Forskningsöversikt (refereegranskat)abstract
- Alzheimer's disease (AD) is a neurodegenerative disease affecting the brain. Today there are three cerebrospinal fluid (CSF) biomarkers, amyloid-β consisting of 42 amino acids (Aβ42), total-tau (t-tau) and phosphorylated-tau (p-tau), which combined have sensitivity and specificity figures around 80%. However, pathological studies have shown that comorbidity is a common feature in AD and that the three currently used CSF biomarkers do not optimally reflect the activity of the disease process. Thus, additional markers are needed. Areas covered: In the present review, we screened PubMed for articles published the last five years (2012-2017) for proteomic studies in CSF with the criteria that AD had to be included as one of the diagnostic groups. Based on inclusion criteria, 28 papers were included reporting in total 224 biomarker-data that were altered in AD compared to control. Both mass spectrometry and multi-panel immunoassays were considered as proteomic studies. Expert commentary: A large number of pilot studies have been reported but so far there is a lack of replicated findings and to date no CSF biomarker discovered in proteomic studies has reached the clinic to aid in the diagnostic work-up of patients with cognitive impairment.
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| 33. |
- Sjödin, Simon, et al.
(författare)
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Endo-lysosomal proteins and ubiquitin CSF concentrations in Alzheimer's and Parkinson's disease
- 2019
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Ingår i: Alzheimer's Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Increasing evidence implicates dysfunctional proteostasis and the involvement of the autophagic and endo-lysosomal system and the ubiquitin-proteasome system in neurodegenerative diseases. In Alzheimer's disease (AD), there is an accumulation of autophagic vacuoles within the neurons. In Parkinson's disease (PD), susceptibility has been linked to genes encoding proteins involved in autophagy and lysosomal function, as well as mutations causing lysosomal disorders. Furthermore, both diseases are characterized by the accumulation of protein aggregates. Methods Proteins associated with endocytosis, lysosomal function, and the ubiquitin-proteasome system were identified in the cerebrospinal fluid (CSF) and targeted by combining solid-phase extraction and parallel reaction monitoring mass spectrometry. In total, 50 peptides from 18 proteins were quantified in three cross-sectional cohorts including AD (N = 61), PD (N = 21), prodromal AD (N = 10), stable mild cognitive impairment (N = 15), and controls (N = 68). Results A pilot study, including subjects selected based on their AD CSF core biomarker concentrations, showed increased concentrations of several targeted proteins in subjects with core biomarker levels indicating AD pathology compared to controls. Next, in a clinically characterized cohort, lower concentrations in CSF of proteins in PD were found compared to subjects with prodromal AD. Further investigation in an additional clinical study again revealed lower concentrations in CSF of proteins in PD compared to controls and AD. Conclusion In summary, significantly different peptide CSF concentrations were identified from proteins AP2B1, C9, CTSB, CTSF, GM2A, LAMP1, LAMP2, TCN2, and ubiquitin. Proteins found to have altered concentrations in more than one study were AP2B1, CTSB, CTSF, GM2A, LAMP2, and ubiquitin. Interestingly, given the genetic implication of lysosomal function in PD, we did identify the CSF concentrations of CTSB, CTSF, GM2A, and LAMP2 to be altered. However, we also found differences in proteins associated with endocytosis (AP2B1) and the ubiquitin-proteasome system (ubiquitin). No difference in any peptide CSF concentration was found in clinically characterized subjects with AD compared to controls. In conclusion, CSF analyses of subjects with PD suggest a general lysosomal dysfunction, which resonates well with recent genetic findings, while such changes are minor or absent in AD.
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| 34. |
- Sjödin, Simon, et al.
(författare)
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Mass Spectrometric Analysis of Cerebrospinal Fluid Ubiquitin in Alzheimer's Disease and Parkinsonian Disorders
- 2017
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Ingår i: Proteomics - Clinical Applications. - : Wiley. - 1862-8346 .- 1862-8354. ; 11:11-12
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Dysfunctional proteostasis, with decreased protein degradation and an accumulation of ubiquitin into aggregated protein inclusions, is a feature of neurodegenerative diseases. Identifying new potential biomarkers in cerebrospinal fluid (CSF) reflecting this process could contribute important information on pathophysiology. Experimental design: A developed method combining SPE and PRM-MS is employed to monitor the concentration of ubiquitin in CSF from subjects with Alzheimer's disease (AD), Parkinson's disease (PD), and progressive supranuclear palsy (PSP). Four independent cross-sectional studies are conducted, studies 1–4, including controls (n = 86) and participants with AD (n = 60), PD (n = 15), and PSP (n = 11). Results: The method shows a repeatability and intermediate precision not exceeding 6.1 and 7.9%, respectively. The determined LOD is 0.1 nm and the LOQ range between 0.625 and 80 nm. The CSF ubiquitin concentration is 1.2–1.5-fold higher in AD patients compared with controls in the three independent AD-control studies (Study 1, p < 0.001; Study 2, p < 0.001; and Study 3, p = 0.003). In the fourth study, there is no difference in PD or PSP, compared to controls. Conclusion and clinical relevance: CSF ubiquitin may reflect dysfunctional proteostasis in AD. The described method can be used for further exploration of ubiquitin as a potential biomarker in neurodegenerative diseases.
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| 35. |
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| 36. |
- van den Berg, E., et al.
(författare)
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Cerebrospinal Fluid Panel of Synaptic Proteins in Cerebral Amyloid Angiopathy and Alzheimer's Disease
- 2023
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 92:2, s. 467-475
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Tidskriftsartikel (refereegranskat)abstract
- Background: Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA) share pathogenic pathways related to amyloid-beta deposition. Whereas AD is known to affect synaptic function, such an association for CAA remains yet unknown. Objective: We therefore aimed to investigate synaptic dysfunction in CAA. Methods: Multiple reaction monitoring mass spectrometry was used to quantify cerebrospinal fluid (CSF) concentrations of 15 synaptic proteins in CAA and AD patients, and age- and sex-matched cognitively unimpaired controls. Results: We included 25 patients with CAA, 49 patients with AD, and 25 controls. Only neuronal pentraxin-2 levels were decreased in the CSF of CAA patients compared with controls (p = 0.04). CSF concentrations of 12 other synaptic proteins were all increased in AD compared with CAA or controls (all p= 0.01) and were unchanged between CAA and controls. Synaptic protein concentrations in the subgroup ofCAApatients positive forADbiomarkers (CAA/ATN+; n = 6) were similar to AD patients, while levels in CAA/ATN- (n = 19) were comparable with those in controls. A regression model including all synaptic proteins differentiated CAA from AD at high accuracy levels (area under the curve 0.987). Conclusion: In contrast to AD, synaptic CSF biomarkers were found to be largely unchanged in CAA. Moreover, concomitant AD pathology in CAA is associated with abnormal synaptic protein levels. Impaired synaptic function in AD was confirmed in this independent cohort. Our findings support an apparent differential involvement of synaptic dysfunction in CAA and AD and may reflect distinct pathological mechanisms.
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| 37. |
- Zetterberg, Henrik, 1973, et al.
(författare)
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Clinical proteomics in neurodegenerative disorders.
- 2008
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Ingår i: Acta neurologica Scandinavica. - : Hindawi Limited. - 1600-0404 .- 0001-6314. ; 118:1, s. 1-11
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Forskningsöversikt (refereegranskat)abstract
- Neurodegenerative disorders are characterized by neuronal impairment that eventually leads to neuronal death. In spite of the brain's known capacity for regeneration, lost neurons are difficult to replace. Therefore, drugs aimed at inhibiting neurodegenerative processes are likely to be most effective if the treatment is initiated as early as possible. However, clinical manifestations in early disease stages are often numerous, subtle and difficult to diagnose. This is where biomarkers that specifically reflect onset of pathology, directly or indirectly, may have a profound impact on diagnosis making in the future. A triplet of biomarkers for Alzheimer's disease (AD), total and hyperphosphorylated tau and the 42 amino acid isoform of beta-amyloid, has already been established for early detection of AD before the onset of dementia. However, more biomarkers are needed both for AD and for other neurodegenerative disorders, such as Parkinson's disease, frontotemporal dementia and amyotrophic lateral sclerosis. This review provides an update on recent advances in clinical neuroproteomics, a biomarker discovery field that has expanded immensely during the last decade, and gives an overview of the most commonly used techniques and the major clinically relevant findings these techniques have lead to.
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| 38. |
- Öhrfelt, Annika, 1973, et al.
(författare)
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The pre-synaptic vesicle protein synaptotagmin is a novel biomarker for Alzheimer's disease
- 2016
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Synaptic degeneration is a central pathogenic event in Alzheimer's disease that occurs early during the course of disease and correlates with cognitive symptoms. The pre-synaptic vesicle protein synaptotagmin-1 appears to be essential for the maintenance of an intact synaptic transmission and cognitive function. Synaptotagmin-1 in cerebrospinal fluid is a candidate Alzheimer biomarker for synaptic dysfunction that also may correlate with cognitive decline. Methods: In this study, a novel mass spectrometry-based assay for measurement of cerebrospinal fluid synaptotagmin-1 was developed, and was evaluated in two independent sample sets of patients and controls. Sample set I included cerebrospinal fluid samples from patients with dementia due to Alzheimer's disease (N = 17, age 52-86 years), patients with mild cognitive impairment due to Alzheimer's disease (N = 5, age 62-88 years), and controls (N = 17, age 41-82 years). Sample set II included cerebrospinal fluid samples from patients with dementia due to Alzheimer's disease (N = 24, age 52-84 years), patients with mild cognitive impairment due to Alzheimer's disease (N = 18, age 58-83 years), and controls (N = 36, age 43-80 years). Results: The reproducibility of the novel method showed coefficients of variation of the measured synaptotagmin-1 peptide 215-223 (VPYSELGGK) and peptide 238-245 (HDIIGEFK) of 14 % or below. In both investigated sample sets, the CSF levels of synaptotagmin-1 were significantly increased in patients with dementia due to Alzheimer's disease (P <= 0.0001) and in patients with mild cognitive impairment due to Alzheimer's disease (P < 0.001). In addition, in sample set I the synaptotagmin-1 level was significantly higher in patients with mild cognitive impairment due to Alzheimer's disease compared with patients with dementia due to Alzheimer's disease (P <= 0.05). Conclusions: Cerebrospinal fluid synaptotagmin-1 is a promising biomarker to monitor synaptic dysfunction and degeneration in Alzheimer's disease that may be useful for clinical diagnosis, to monitor effect on synaptic integrity by novel drug candidates, and to explore pathophysiology directly in patients with Alzheimer's disease.
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| 39. |
- Öhrfelt Olsson, Annika, 1973, et al.
(författare)
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Identification of Novel α-Synuclein Isoforms in Human Brain Tissue by using an Online NanoLC-ESI-FTICR-MS Method.
- 2011
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Ingår i: Neurochemical research. - : Springer Science and Business Media LLC. - 1573-6903 .- 0364-3190. ; 36:11, s. 2029-2042
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) are neurodegenerative diseases that are characterized by intra-neuronal inclusions of Lewy bodies in distinct brain regions. These inclusions consist mainly of aggregated α-synuclein (α-syn) protein. The present study used immunoprecipitation combined with nanoflow liquid chromatography (LC) coupled to high resolution electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry (ESI-FTICR-MS/MS) to determine known and novel isoforms of α-syn in brain tissue homogenates. N-terminally acetylated full-length α-syn (Ac-α-syn(1-140)) and two N-terminally acetylated C-terminally truncated forms of α-syn (Ac-α-syn(1-139) and Ac-α-syn(1-103)) were found. The different forms of α-syn were further studied by Western blotting in brain tissue homogenates from the temporal cortex Brodmann area 36 (BA36) and the dorsolateral prefrontal cortex BA9 derived from controls, patients with DLB and PD with dementia (PDD). Quantification of α-syn in each brain tissue fraction was performed using a novel enzyme-linked immunosorbent assay (ELISA).
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| 40. |
- Bartl, Michael, et al.
(författare)
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Lysosomal and synaptic dysfunction markers in longitudinal cerebrospinal fluid of de novo Parkinson's disease
- 2024
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Ingår i: NPJ PARKINSONS DISEASE. - 2373-8057. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Lysosomal and synaptic dysfunctions are hallmarks in neurodegeneration and potentially relevant as biomarkers, but data on early Parkinson's disease (PD) is lacking. We performed targeted mass spectrometry with an established protein panel, assessing autophagy and synaptic function in cerebrospinal fluid (CSF) of drug-na & iuml;ve de novo PD, and sex-/age-matched healthy controls (HC) cross-sectionally (88 PD, 46 HC) and longitudinally (104 PD, 58 HC) over 10 years. Multiple markers of autophagy, synaptic plasticity, and secretory pathways were reduced in PD. We added samples from prodromal subjects (9 cross-sectional, 12 longitudinal) with isolated REM sleep behavior disorder, revealing secretogranin-2 already decreased compared to controls. Machine learning identified neuronal pentraxin receptor and neurosecretory protein VGF as most relevant for discriminating between groups. CSF levels of LAMP2, neuronal pentraxins, and syntaxins in PD correlated with clinical progression, showing predictive potential for motor- and non-motor symptoms as a valid basis for future drug trials.
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| 41. |
- Bhattacharjee, Payel, 1984, et al.
(författare)
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Mass Spectrometric Analysis of Lewy Body-Enriched alpha-Synuclein in Parkinson's Disease
- 2019
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 18:5, s. 2109-2120
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease (PD) is characterized by intraneuronal inclusions of aggregated alpha-synuclein protein (so-called Lewy bodies) in distinct brain regions. Multiple posttranslational modifications may affect the structure and function of alpha-synuclein. Mass spectrometry-based analysis may be useful for the characterization and quantitation of alpha-synuclein forms, but has proven challenging, mainly due to the insolubility of Lewy bodies in aqueous buffer. In the present study, we developed a novel method by combining differential solubilization with immunoprecipitation and targeted proteomics using liquid chromatography and tandem mass spectrometry. Brain tissue homogenization and sample preparation were modified to facilitate analysis of soluble, detergent-soluble, and detergent-insoluble protein fractions (Lewy body-enriched). The method was used to compare alpha-synuclein forms from cingulate cortex (affected) and occipital cortex (unaffected) in two study sets of PD patients and controls. We identified similar to 20 modified alpha-synuclein variants, including species with N-terminal acetylation and C-terminal truncations at amino acids 103 and 119. The levels of alpha-synuclein forms Ac-alpha-syn(1-6), alpha-syn(13-21), alpha-syn(35-43), alpha-syn(46-58), alpha-syn(61-80), and alpha-syn(81-96) except alpha-syn(103-119) were significantly increased in PD cingulate region compared to controls in the Lewy body-enriched alpha-synuclein fraction. In the soluble fraction, only Ac-alpha-syn(1-6) was significantly increased in PD compared to controls. None of the detected alpha-synuclein variants were Lewy body-specific, but acetylated forms should be examined further as potential biomarkers for abnormal alpha-synuclein accumulation.
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| 42. |
- Brinkmalm, Ann, et al.
(författare)
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Detection of α-Synuclein in Biological Samples Using Mass Spectrometry
- 2019
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Ingår i: Methods in molecular biology (Clifton, N.J.). - New York, NY : Springer. - 1940-6029. ; , s. 209-220
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Bokkapitel (refereegranskat)abstract
- Here we describe a method using mass spectrometry to characterize and quantify immuno-enriched α-synuclein forms from biochemically fractionated brain tissue.
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| 43. |
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| 44. |
- Brockmann, K., et al.
(författare)
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Association between CSF alpha-synuclein seeding activity and genetic status in Parkinson's disease and dementia with Lewy bodies
- 2021
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The clinicopathological heterogeneity in Lewy-body diseases (LBD) highlights the need for pathology-driven biomarkers in-vivo. Misfolded alpha-synuclein (alpha-Syn) is a lead candidate based on its crucial role in disease pathophysiology. Real-time quaking-induced conversion (RT-QuIC) analysis of CSF has recently shown high sensitivity and specificity for the detection of misfolded alpha-Syn in patients with Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In this study we performed the CSF RT-QuIC assay in 236 PD and 49 DLB patients enriched for different genetic forms with mutations in GBA, parkin, PINK1, DJ1, and LRRK2. A subgroup of 100 PD patients was also analysed longitudinally. We correlated kinetic seeding parameters of RT-QuIC with genetic status and CSF protein levels of molecular pathways linked to alpha-Syn proteostasis. Overall, 85% of PD and 86% of DLB patients showed positive RT-QuIC alpha-Syn seeding activity. Seeding profiles were significantly associated with mutation status across the spectrum of genetic LBD. In PD patients, we detected positive alpha-Syn seeding in 93% of patients carrying severe GBA mutations, in 78% with LRRK2 mutations, in 59% carrying heterozygous mutations in recessive genes, and in none of those with bi-allelic mutations in recessive genes. Among PD patients, those with severe GBA mutations showed the highest seeding activity based on RT-QuIC kinetic parameters and the highest proportion of samples with 4 out of 4 positive replicates. In DLB patients, 100% with GBA mutations showed positive alpha-Syn seeding compared to 79% of wildtype DLB. Moreover, we found an association between alpha-Syn seeding activity and reduced CSF levels of proteins linked to alpha-Syn proteostasis, specifically lysosome-associated membrane glycoprotein 2 and neurosecretory protein VGF. These findings highlight the value of alpha-Syn seeding activity as an in-vivo marker of Lewy-body pathology and support its use for patient stratification in clinical trials targeting alpha-Syn.
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| 45. |
- Camporesi, Elena, et al.
(författare)
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Fluid Biomarkers for Synaptic Dysfunction and Loss
- 2020
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Ingår i: Biomarker Insights. - : SAGE Publications. - 1177-2719. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Synapses are the site for brain communication where information is transmitted between neurons and stored for memory formation. Synaptic degeneration is a global and early pathogenic event in neurodegenerative disorders with reduced levels of pre- and postsynaptic proteins being recognized as a core feature of Alzheimer's disease (AD) pathophysiology. Together with AD, other neurodegenerative and neurodevelopmental disorders show altered synaptic homeostasis as an important pathogenic event, and due to that, they are commonly referred to as synaptopathies. The exact mechanisms of synapse dysfunction in the different diseases are not well understood and their study would help understanding the pathogenic role of synaptic degeneration, as well as differences and commonalities among them and highlight candidate synaptic biomarkers for specific disorders. The assessment of synaptic proteins in cerebrospinal fluid (CSF), which can reflect synaptic dysfunction in patients with cognitive disorders, is a keen area of interest. Substantial research efforts are now directed toward the investigation of CSF synaptic pathology to improve the diagnosis of neurodegenerative disorders at an early stage as well as to monitor clinical progression. In this review, we will first summarize the pathological events that lead to synapse loss and then discuss the available data on established (eg, neurogranin, SNAP-25, synaptotagmin-1, GAP-43, and alpha-syn) and emerging (eg, synaptic vesicle glycoprotein 2A and neuronal pentraxins) CSF biomarkers for synapse dysfunction, while highlighting possible utilities, disease specificity, and technical challenges for their detection.
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| 46. |
- Casaletto, K. B., et al.
(författare)
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Tripartite Relationship Among Synaptic, Amyloid, and Tau Proteins An In Vivo and Postmortem Study
- 2021
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 97:3
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Tidskriftsartikel (refereegranskat)abstract
- Objective To test the hypothesis that fundamental relationships along the amyloid, tau, and neurodegeneration (A/T/N) cascade depend on synaptic integrity in older adults in vivo and postmortem. Methods The 2 independent observational, cross-sectional cohorts included (1) in vivo community-dwelling, clinically normal adults from the University of California, San Francisco Memory and Aging Center who completed lumbar puncture and MRI (exclusion criteria, Clinical Dementia Rating score >0) and (2) postmortem decedents from the Rush Memory and Aging Project (exclusion criteria, inability to sign informed consent). In vivo measures included CSF synaptic proteins (synaptotagmin-1, synaptosome associated protein-25, neurogranin, and growth associated protein-43), beta-amyloid (A beta(42/40)), tau phosphorylated at amino acid 181 (ptau(181)), and MRI gray matter volume (GMV). Postmortem measures captured brain tissue levels of presynaptic proteins (complexin-I, complexin-II, vesicle associated membrane protein (VAMP), and SNARE complex) and neuritic plaque and neurofibrillary tangle (NFT) counts. Regression models tested statistical moderation of synaptic protein levels along the A/T/N cascade (synaptic proteins x amyloid on tau, and synaptic proteins x tau on GMV). Results Sixty-eight in vivo older adults (age 71 years, 43% female) and 633 decedents (age 90 years, 68% female, 34% clinically normal) were included. Each in vivo CSF synaptic protein moderated the relationship between A beta(42/40) and ptau(181) (-0.23 < beta < -0.12, p < 0.05) and the relationship between ptau(181) and GMV (-0.49
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| 47. |
- Clarke, Mica T M, et al.
(författare)
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CSF synaptic protein concentrations are raised in those with atypical Alzheimer's disease but not frontotemporal dementia.
- 2019
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Ingår i: Alzheimer's research & therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Increased CSF levels of a number of synaptic markers have been reported in Alzheimer's disease (AD), but little is known about their concentrations in frontotemporal dementia (FTD). We investigated this in three synaptic proteins, neurogranin, SNAP-25, and synaptotagmin-1.CSF samples were analysed from 66 patients with a disorder in the FTD spectrum and 19 healthy controls. Patients were stratified by their tau to Aβ42 ratio: those with a ratio of >1 considered as having likely AD pathology, i.e. an atypical form of AD ('AD biomarker' group [n=18]), and <1 as likely FTD pathology ('FTD biomarker' group [n=48]). A subgroup analysis compared those in the FTD group with likely tau (n=7) and TDP-43 (n=18) pathology. Concentrations of neurogranin were measured using two different ELISAs (Ng22 and Ng36), and concentrations of two SNAP-25 fragments (SNAP-25tot and SNAP-25aa40) and synaptotagmin-1 were measured via mass spectrometry.The AD biomarker group had significantly higher concentrations of all synaptic proteins compared to controls except for synaptotagmin-1 where there was only a trend to increased levels-Ng22, AD mean 232.2 (standard deviation 138.9) pg/ml, controls 137.6 (95.9); Ng36, 225.5 (148.8) pg/ml, 130.0 (80.9); SNAP-25tot, 71.4 (27.9) pM, 53.5 (11.7); SNAP-25aa40, 14.0 (6.3), 7.9 (2.3) pM; and synaptotagmin-1, 287.7 (156.0) pM, 238.3 (71.4). All synaptic measures were significantly higher in the atypical AD group than the FTD biomarker group except for Ng36 where there was only a trend to increased levels-Ng22, 114.0 (117.5); Ng36, 171.1 (75.2); SNAP-25tot, 49.2 (16.7); SNAP-25aa40, 8.2 (3.4); and synaptotagmin-1, 197.1 (78.9). No markers were higher in the FTD biomarker group than controls. No significant differences were seen in the subgroup analysis, but there was a trend to increased levels in those with likely tau pathology.No CSF synaptic proteins have been shown to be abnormal in those with likely FTD pathologically. Higher CSF synaptic protein concentrations of neurogranin, SNAP-25, and synaptotagmin-1 appear to be related to AD pathology.
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