| 61. |
- Nilsson, K. Peter R., et al.
(författare)
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Imaging distinct conformational states of amyloid-beta fibrils in Alzheimer's disease using novel luminescent probes
- 2007
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Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 2:8, s. 553-560
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Tidskriftsartikel (refereegranskat)abstract
- Using luminescent conjugated polyelectrolyte probes (LCPs), we demonstrate the possibility to distinguish amyloid-β 1–42 peptide (Aβ1–42) fibril conformations, by analyzing in vitro generated amyloid fibrils of Aβ1–42 formed under quiescent and agitated conditions. LCPs were then shown to resolve such conformational heterogeneity of amyloid deposits in vivo. A diversity of amyloid deposits depending upon morphology and anatomic location was illustrated with LCPs in frozen ex vivo brain sections from a transgenic mouse model (tg-APP swe) of Alzheimer’s disease. Comparative LCP fluorescence showed that compact-core plaques of amyloid β precursor protein transgenic mice were composed of rigid dense amyloid. A more abundant form of amyloid plaque displayed morphology of a compact center with a protruding diffuse exterior. Surprisingly, the compact center of these plaques showed disordered conformations of the fibrils, and the exterior was composed of rigid amyloid protruding from the disordered center. This type of plaque appears to grow from more loosely assembled regions toward solidified amyloid tentacles. This work demonstrates how application of LCPs can prove helpful to monitor aggregate structure of in vivo formed amyloid deposits such as architecture, maturity, and origin.
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| 62. |
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| 63. |
- Nilsson, Peter, et al.
(författare)
-
Imaging distinct conformational states of amyloid-β fibrils in Alzheimer's disease using novel luminescent probes
- 2007
-
Ingår i: ACS Chemical Biology. - : American Chemical Society (ACS). - 1554-8929 .- 1554-8937. ; 2:8, s. 553-560
-
Tidskriftsartikel (refereegranskat)abstract
- Using luminescent conjugated polyelectrolyte probes (LCPs), we demonstrate the possibility to distinguish amyloid-β 1-42 peptide (Aβ1-42) fibril conformations, by analyzing in vitro generated amyloid fibrils of Aβ1-42 formed under quiescent and agitated conditions. LCPs were then shown to resolve such conformational heterogeneity of amyloid deposits in vivo. A diversity of amyloid deposits depending upon morphology and anatomic location was illustrated with LCPs in frozen ex vivo brain sections from a transgenic mouse model (tg-APPswe) of Alzheimer's disease. Comparative LCP fluorescence showed that compact-core plaques of amyloid β precursor protein transgenic mice were composed of rigid dense amyloid. A more abundant form of amyloid plaque displayed morphology of a compact center with a protruding diffuse exterior. Surprisingly, the compact center of these plaques showed disordered conformations of the fibrils, and the exterior was composed of rigid amyloid protruding from the disordered center. This type of plaque appears to grow from more loosely assembled regions toward solidified amyloid tentacles. This work demonstrates how application of LCPs can prove helpful to monitor aggregate structure of in vivo formed amyloid deposits such as architecture, maturity, and origin.
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| 64. |
- O'Callaghan, Paul, et al.
(författare)
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Heparan sulfate accumulation with Abeta deposits in Alzheimer's disease and Tg2576 mice is contributed by glial cells
- 2008
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Ingår i: Brain Pathology. - : Wiley. - 1015-6305 .- 1750-3639. ; 18:4, s. 548-561
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid beta-peptide (Abeta) plaques, one of the major neuropathological lesions in Alzheimer's disease (AD), can be broadly subdivided into two morphological categories: neuritic and diffuse. Heparan sulfate (HS) and HS proteoglycans (HSPGs) are codeposits of multiple amyloidoses, including AD. Although HS has been considered a limiting factor in the initiation of amyloid deposition, the pathological implications of HS in Abeta deposits of AD remain unclear. In this study, immunohistochemistry combined with fluorescence and confocal microscopy was employed to gain deeper insight into the accumulation of HS with Abeta plaques in sporadic and familial AD. Here we demonstrate that HS preferentially accumulated around the Abeta40 dense cores of neuritic plaques, but was largely absent from diffuse Abeta42 plaques, suggesting that Abeta42 deposition may occur independently of HS. A codeposition pattern of HS with Abeta deposits in Tg2576 mice was also examined. We identified the membrane-bound HSPGs, glypican-1 (GPC1) and syndecan-3 (SDC3), in glial cells associated with Abeta deposits, proximal to sites of HS accumulation. In mouse primary glial cultures, we observed increased levels of GPC1 and SDC3 following Abeta stimulation. These results suggest that HS codeposits with Abeta40 in neuritic plaques and is mainly derived from glial cells.
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| 65. |
- Pagnon de la Vega, María, et al.
(författare)
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Altered amyloid-β structure markedly reduces gliosis in the brain of mice harboring the Uppsala APP deletion
- 2024
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Ingår i: Acta neuropathologica communications. - : BioMed Central (BMC). - 2051-5960. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Deposition of amyloid beta (Aβ) into plaques is a major hallmark of Alzheimer’s disease (AD). Different amyloid precursor protein (APP) mutations cause early-onset AD by altering the production or aggregation properties of Aβ. We recently identified the Uppsala APP mutation (APPUpp), which causes Aβ pathology by a triple mechanism: increased β-secretase and altered α-secretase APP cleavage, leading to increased formation of a unique Aβ conformer that rapidly aggregates and deposits in the brain. The aim of this study was to further explore the effects of APPUpp in a transgenic mouse model (tg-UppSwe), expressing human APP with the APPUpp mutation together with the APPSwe mutation. Aβ pathology was studied in tg-UppSwe brains at different ages, using ELISA and immunohistochemistry. In vivo PET imaging with three different PET radioligands was conducted in aged tg-UppSwe mice and two other mouse models; tg-ArcSwe and tg-Swe. Finally, glial responses to Aβ pathology were studied in cell culture models and mouse brain tissue, using ELISA and immunohistochemistry. Tg-UppSwe mice displayed increased β-secretase cleavage and suppressed α-secretase cleavage, resulting in AβUpp42 dominated diffuse plaque pathology appearing from the age of 5–6 months. The γ-secretase cleavage was not affected. Contrary to tg-ArcSwe and tg-Swe mice, tg-UppSwe mice were [11C]PiB-PET negative. Antibody-based PET with the 3D6 ligand visualized Aβ pathology in all models, whereas the Aβ protofibril selective mAb158 ligand did not give any signals in tg-UppSwe mice. Moreover, unlike the other two models, tg-UppSwe mice displayed a very faint glial response to the Aβ pathology. The tg-UppSwe mouse model thus recapitulates several pathological features of the Uppsala APP mutation carriers. The presumed unique structural features of AβUpp42 aggregates were found to affect their interaction with anti-Aβ antibodies and profoundly modify the Aβ-mediated glial response, which may be important aspects to consider for further development of AD therapies.
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| 66. |
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| 67. |
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| 68. |
- Petzold, Axel, et al.
(författare)
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Neurofilament ELISA validation
- 2010
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Ingår i: JOURNAL OF IMMUNOLOGICAL METHODS. - 0022-1759. ; 352:1-2, s. 23-31
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Tidskriftsartikel (refereegranskat)
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| 69. |
- Petzold, Axel, et al.
(författare)
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Neurofilament ELISA validation
- 2010
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Ingår i: JIM - Journal of Immunological Methods. - : Elsevier BV. - 0022-1759 .- 1872-7905. ; 352:1-2, s. 23-31
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Neurofilament proteins (Nf) are highly specific biomarkers for neuronal death and axonal degeneration. As these markers become more widely used, an inter-laboratory validation study is required to identify assay criteria for high quality performance. METHODS: The UmanDiagnostics NF-light (R)enzyme-linked immunoabsorbent assays (ELISA) for the neurofilament light chain (NfL, 68kDa) was used to test the intra-assay and inter-laboratory coefficient of variation (CV) between 35 laboratories worldwide on 15 cerebrospinal fluid (CSF) samples. Critical factors, such as sample transport and storage, analytical delays, reaction temperature and time, the laboratories' accuracy and preparation of standards were documented and used for the statistical analyses. RESULTS: The intra-laboratory CV averaged 3.3% and the inter-laboratory CV 59%. The results from the test laboratories correlated with those from the reference laboratory (R=0.60, p<0.0001). Correcting for critical factors improved the strength of the correlation. Differences in the accuracy of standard preparation were identified as the most critical factor. Correcting for the error introduced by variation in the protein standards improved the correlation to R=0.98, p<0.0001 with an averaged inter-laboratory CV of 14%. The corrected overall inter-rater agreement was subtantial (0.6) according to Fleiss' multi-rater kappa and Gwet's AC1 statistics. CONCLUSION: This multi-center validation study identified the lack of preparation of accurate and consistent protein standards as the main reason for a poor inter-laboratory CV. This issue is also relevant to other protein biomarkers based on this type of assay and will need to be solved in order to achieve an acceptable level of analytical accuracy. The raw data of this study is available online.
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| 70. |
- Philipson, Ola, et al.
(författare)
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A highly insoluble state of Abeta similar to that of Alzheimer's disease brain is found in Arctic APP transgenic mice.
- 2009
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Ingår i: Neurobiology of aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 30:9, s. 1393-405
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid-beta (Abeta) is a major drug target in Alzheimer's disease. Here, we demonstrate that deposited Abeta is SDS insoluble in tgAPP-ArcSwe, a transgenic mouse model harboring the Arctic (E693G) and Swedish (KM670/671NL) APP mutations. Formic acid was needed to extract the majority of deposited Abeta in both tgAPP-ArcSwe and Alzheimer's disease brain, but not in a commonly used type of mouse model with the Swedish mutation alone. Interestingly, the insoluble state of Arctic Abeta was determined early on and did not gradually evolve with time. In tgAPP-ArcSwe, Abeta plaques displayed a patchy morphology with bundles of Abeta fibrils, whereas amyloid cores in tgAPP-Swe were circular with radiating fibrils. Amyloid was more densely stacked in tgAPP-ArcSwe, as demonstrated with a conformation sensitive probe. A reduced increase in plasma Abeta was observed following acute administration of an Abeta antibody in tgAPP-ArcSwe, results that might imply reduced brain to plasma Abeta efflux. TgAPP-ArcSwe, with its insoluble state of deposited Abeta, could serve as a complementary model to better predict the outcome of clinical trials.
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