| 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
-
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)
-
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
-
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. |
- 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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| 23. |
- 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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| 24. |
- 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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| 25. |
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