| 1. |
- Hölttä, Mikko, et al.
(författare)
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Peptidome Analysis of Cerebrospinal Fluid by LC-MALDI MS
- 2012
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- We report on the analysis of endogenous peptides in cerebrospinal fluid (CSF) by mass spectrometry. A method was developed for preparation of peptide extracts from CSF. Analysis of the extracts by offline LC-MALDI MS resulted in the detection of 3,000-4,000 peptide-like features. Out of these, 730 peptides were identified by MS/MS. The majority of these peptides have not been previously reported in CSF. The identified peptides were found to originate from 104 proteins, of which several have been reported to be involved in different disorders of the central nervous system. These results support the notion that CSF peptidomics may be viable complement to proteomics in the search of biomarkers of CNS disorders.
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| 2. |
- Portelius, Erik, 1977, et al.
(författare)
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Altered Cerebrospinal Fluid Levels of Amyloid beta and Amyloid Precursor-Like Protein 1 Peptides in Down's Syndrome
- 2014
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Ingår i: Neuromolecular medicine. - : Springer Science and Business Media LLC. - 1535-1084 .- 1559-1174. ; 16:2, s. 510-516
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Tidskriftsartikel (refereegranskat)abstract
- Down's syndrome (DS) patients develop early Alzheimer's disease pathology with abundant cortical amyloid plaques, likely due to overproduction of the amyloid precursor protein (APP), which subsequently leads to amyloid beta (A beta) aggregation. This is reflected in cerebrospinal fluid (CSF) levels of the 42-amino acid long A beta peptide (A beta 1-42), which are increased in young DS patients and decreases with age. However, it is unclear whether DS also affects other aspects of A beta metabolism, including production of shorter C- and N-terminal truncated A beta peptides, and production of peptides from the amyloid precursor-like protein 1 (APLP1), which is related to APP, and cleaved by the same enzymatic processing machinery. APLP1-derived peptides may be surrogate markers for A beta 1-42 production in the brain. Here, we used hybrid immunoaffinity-mass spectrometry and enzyme-linked immunosorbent assays to monitor several A beta and APLP1 peptides in CSF from DS patients (n = 12) and healthy controls (n = 20). CSF levels of A beta 1-42 and three endogenous peptides derived from APLP1 (APL1 beta 25, APL1 beta 27 and APL1 beta 28) were decreased in DS compared with controls, while a specific A beta peptide, A beta 1-28, was increased in a majority of the DS individuals. This study indicates that DS causes previously unknown specific alterations of APP and APLP1 metabolism.
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| 3. |
- 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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