| 1. |
- de la Vega, Maria Pagnon, et al.
(författare)
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The Uppsala APP deletion causes early onset autosomal dominant Alzheimer's disease by altering APP processing and increasing amyloid beta fibril formation
- 2021
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 13:606
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Tidskriftsartikel (refereegranskat)abstract
- Point mutations in the amyloid precursor protein gene (APP) cause familial Alzheimer's disease (AD) by increasing generation or altering conformation of amyloid beta (A beta). Here, we describe the Uppsala APP mutation (Delta 690-695), the first reported deletion causing autosomal dominant AD. Affected individuals have an age at symptom onset in their early forties and suffer from a rapidly progressing disease course. Symptoms and biomarkers are typical of AD, with the exception of normal cerebrospinal fluid (CSF) A beta 42 and only slightly pathological amyloid-positron emission tomography signals. Mass spectrometry and Western blot analyses of patient CSF and media from experimental cell cultures indicate that the Uppsala APP mutation alters APP processing by increasing beta-secretase cleavage and affecting alpha-secretase cleavage. Furthermore, in vitro aggregation studies and analyses of patient brain tissue samples indicate that the longer form of mutated A beta, A beta Upp1-42(Delta 19-24), accelerates the formation of fibrils with unique polymorphs and their deposition into amyloid plaques in the affected brain.
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| 2. |
- Emami Khoonsari, Payam, et al.
(författare)
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Chitinase-3-like protein 1 (CH3L1) and Neurosecretory protein VGF (VGF) as two novel CSF biomarker candidates for improved diagnostics in Alzheimer’s disease
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Alzheimer’s disease (AD) is a chronic neurodegenerative disorder characterized by amyloid-β (Aβ) plaque deposition and accumulation of intracellular neurofibrillary tangles. This pathology is mirrored in the cerebrospinal fluid (CSF), where decreased Aβ42 together with increased total (t-tau) and phospho-tau (p-tau) today is used as a diagnostic marker. Although these biomarkers have a fairly good sensitivity and specificity, additional biomarkers are needed to further improve the accuracy for early disease detection and to monitor disease development. In this study, we used mass spectrometry-based shotgun proteomics to investigate the CSF proteome of patients with AD and mild cognitive impairment (MCI) as well as of non-demented controls. By combining the diagnostic markers (Aβ42, total t-tau, and p-tau) with a selection of proteomics biomarkers, the accuracy of predicting MCI to AD conversion increased from 83% to 92% with a specificity of 1.0 and sensitivity of 0.86. Among these markers, the levels of protein chitinase-3-like protein 1 (CH3L1) were significantly higher in AD and MCI converters compared to controls. In addition to Aβ42, t-tau, and p-tau the protein CH3L1 contributed mostly to the prediction accuracy. We also found statistically significant lower CSF levels of the neurosecretory protein VGF (VGF) in AD compared to controls. Taken together, our findings suggest that incorporating new CSF biomarkers can further enhance early diagnosis of AD.
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| 3. |
- Emami Khoonsari, Payam, et al.
(författare)
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Improved Differential Diagnosis of Alzheimer's Disease by Integrating ELISA and Mass Spectrometry-Based Cerebrospinal Fluid Biomarkers
- 2019
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Ingår i: Journal of Alzheimer's Disease. - : IOS PRESS. - 1387-2877 .- 1875-8908. ; 67:2, s. 639-651
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Tidskriftsartikel (refereegranskat)abstract
- Background: Alzheimer's disease (AD) is diagnosed based on a clinical evaluation as well as analyses of classical biomarkers: A beta(42), total tau (t-tau), and phosphorylated tau (p-tau) in cerebrospinal fluid (CSF). Although the sensitivities and specificities of the classical biomarkers are fairly good for detection of AD, there is still a need to develop novel biochemical markers for early detection of AD. Objective: We explored if integration of novel proteins with classical biomarkers in CSF can better discriminate AD from non-AD subjects. Methods: We applied ELISA, mass spectrometry, and multivariate modeling to investigate classical biomarkers and the CSF proteome in subjects (n = 206) with 76 AD patients, 74 mild cognitive impairment (MCI) patients, 11 frontotemporal dementia (FTD) patients, and 45 non-dementia controls. The MCI patients were followed for 4-9 years and 21 of these converted to AD, whereas 53 remained stable. Results: By combining classical CSF biomarkers with twelve novel markers, the area of the ROC curves (AUROCS) of distinguishing AD and MCl/AD converters from non-AD were 93% and 96%, respectively. The FTDs and non-dementia controls were identified versus all other groups with AUROCS of 96% and 87%, respectively. Conclusions: Integration of new and classical CSF biomarkers in a model-based approach can improve the identification of AD, FTD, and non-dementia control subjects.
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| 4. |
- Englund, Hillevi, 1980-, et al.
(författare)
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Oligomerization partially explains the lowering of Aβ42 in Alzheimer's disease cerebrospinal fluid
- 2009
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Ingår i: Neuro-degenerative diseases. - : S. Karger AG. - 1660-2862 .- 1660-2854. ; 6:4, s. 139-147
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Tidskriftsartikel (refereegranskat)abstract
- Background/aim: The lowering of natively analyzed Aβ42 in cerebrospinal fluid (CSF) is used as a diagnostic tool in Alzheimer’s disease (AD). Presence of Aβ oligomers can interfere with such analyses causing underestimation of Aβ levels due to epitope masking. The aim was to investigate if the lowering of CSF Aβ42 seen is caused by oligomerization. Methods: Aβ42 was analyzed under both denaturing and non-denaturing conditions. An Aβ42 oligomer ratio was calculated from these quantifications. Presence of oligomers leads to Aβ42 epitope masking during non-denaturing assays, resulting in a higher ratio. Results: The Aβ42 oligomer ratio was used for assessment of oligomerized Aβ in human CSF, after being evaluated in transgenic mouse brain homogenates. AD and mild cognitive impairment (MCI) samples displayed the expected decrease in natively measured Aβ42 compared to healthy controls and frontotemporal dementia, but not when analyzing under denaturing conditions. Accordingly, AD and MCI CSF had a higher Aβ42 oligomer ratio in CSF. Conclusion: Combining denaturing and non-denaturing quantifications of Aβ42 into an oligomer ratio enables assessment of Aβ oligomers in biological samples. The increased Aβ42 oligomer ratio for AD and MCI indicates presence of oligomers in CSF and that the lowering of natively measured Aβ42 is caused by oligomerization.
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| 5. |
- Giedraitis, Vilmantas, et al.
(författare)
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CALHM1 P86L polymorphism does not alter amyloid-beta or tau in cerebrospinal fluid
- 2010
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 469:2, s. 265-267
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the P86L alteration in CALHM1 (calcium homeostasis modulator-1) was reported to be associated with Alzheimer's disease (AD). Moreover, the risk allele increased amyloid-beta (A beta) levels in conditioned media from cultured cells. Therefore, we hypothesized that CALHM1 P86L may modulate A beta or tau levels in cerebrospinal fluid (CSF). Nearly 200 individuals with AD or other cognitive disorders were included for CSF analysis and CALHM1 genotyping. No significant differences in CSF levels of A beta 42, tau or phospho-tau were found across the various CALHM1 genotypes. In conclusion, we found no evidence that CALHM1 P86L is associated with altered CSF levels of the investigated AD biomarkers.
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| 6. |
- Giedraitis, Vilmantas, et al.
(författare)
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New Alzheimer's disease locus on chromosome 8
- 2006
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 43:12, s. 931-935
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Tidskriftsartikel (refereegranskat)abstract
- Background: Family history is one of the most consistent risk factors for dementia. Therefore, analysis of families with a distinct inheritance pattern of disease can be a powerful approach for the identification of previously unknown disease genes. Objective: To map susceptibility regions for Alzheimer's disease. Methods: A complete genome scan with 369 microsatellite markers was carried out in 12 extended families collected in Sweden. Age at disease onset ranged from 53 to 78 years, but in 10 of the families there was at least one member with age at onset of <= 65 years. Mutations in known early-onset Alzheimer's disease susceptibility genes have been excluded. All people were genotyped for APOE, but no clear linkage with the epsilon 4 allele was observed. Results: Although no common disease locus could be found in all families, in two families an extended haplotype was identified on chromosome 8q shared by all affected members. In one of the families, a non-parametric multi-marker logarithm of the odds (LOD) score of 4.2 (p = 0.004) was obtained and analysis based on a dominant model showed a parametric LOD score of 2.4 for this region. All six affected members of this family shared a haplotype of 10 markers spanning about 40 cM. Three affected members in another family also shared a haplotype in the same region. Conclusion: On the basis of our data, we propose the existence of a dominantly acting Alzheimer's disease susceptibility locus on chromosome 8.
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| 7. |
- Kalimo, H., et al.
(författare)
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Details of neuropathology in Arctic Alzheimer's disease
- 2010
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Ingår i: Abstracts of the XVIIth International Congress of Neuropathology (ICN 2010), Salzburg, Austria, 11-15 September 2010. - : Wiley. ; , s. 22-23
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Kalimo, Hannu, et al.
(författare)
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The Arctic AβPP mutation leads to Alzheimer's disease pathology with highly variable topographic deposition of differentially truncated Aβ
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1, s. 60-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Arctic mutation (p.E693G/p.E22G)fs within the β-amyloid (Aβ) region of the β-amyloid precursor protein gene causes an autosomal dominant disease with clinical picture of typical Alzheimer's disease. Here we report the special character of Arctic AD neuropathology in four deceased patients.RESULTS: Aβ deposition in the brains was wide-spread (Thal phase 5) and profuse. Virtually all parenchymal deposits were composed of non-fibrillar, Congo red negative Aβ aggregates. Congo red only stained angiopathic vessels. Mass spectrometric analyses showed that Aβ deposits contained variably truncated and modified wild type and mutated Aβ species. In three of four Arctic AD brains, most cerebral cortical plaques appeared targetoid with centres containing C-terminally (beyond aa 40) and variably N-terminally truncated Aβ surrounded by coronas immunopositive for Aβx-42. In the fourth patient plaque centres contained almost no Aβ making the plaques ring-shaped. The architectural pattern of plaques also varied between different anatomic regions. Tau pathology corresponded to Braak stage VI, and appeared mainly as delicate neuropil threads (NT) enriched within Aβ plaques. Dystrophic neurites were scarce, while neurofibrillary tangles were relatively common. Neuronal perikarya within the Aβ plaques appeared relatively intact.CONCLUSIONS: In Arctic AD brain differentially truncated abundant Aβ is deposited in plaques of variable numbers and shapes in different regions of the brain (including exceptional targetoid plaques in neocortex). The extracellular non-fibrillar Aβ does not seem to cause overt damage to adjacent neurons or to induce formation of neurofibrillary tangles, supporting the view that intracellular Aβ oligomers are more neurotoxic than extracellular Aβ deposits. However, the enrichment of NTs within plaques suggests some degree of intra-plaque axonal damage including accumulation of hp-tau, which may impair axoplasmic transport, and thereby contribute to synaptic loss. Finally, similarly as the cotton wool plaques in AD resulting from exon 9 deletion in the presenilin-1 gene, the Arctic plaques induced only modest glial and inflammatory tissue reaction.
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| 9. |
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| 10. |
- Pagnon de la Vega, María, 1994-, et al.
(författare)
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Mutation analysis of disease causing genes in patients with early onset or familial forms of Alzheimer’s disease and frontotemporal dementia
- 2022
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Ingår i: BMC Genomics. - : Springer Nature. - 1471-2164. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Background: Most dementia disorders have a clear genetic background and a number of disease genes have beenidentified. Mutations in the tau gene (MAPT) lead to frontotemporal dementia (FTD), whereas mutations in the genesfor the amyloid-β precursor protein (APP) and the presenilins (PSEN1, PSEN2) cause early-onset, dominantly inheritedforms of Alzheimer’s disease (AD).Even if mutations causing Mendelian forms of these diseases are uncommon, elucidation of the pathogenic effects ofsuch mutations have proven important for understanding the pathogenic processes. Here, we performed a screen toidentify novel pathogenic mutations in known disease genes among patients undergoing dementia investigation.Results: Using targeted exome sequencing we have screened all coding exons in eleven known dementia genes(PSEN1, PSEN2, APP, MAPT, APOE, GRN, TARDBP, CHMP2B, TREM2, VCP and FUS) in 102 patients with AD, FTD, otherdementia diagnoses or mild cognitive impairment.We found three AD patients with two previously identified pathogenic mutations in PSEN1 (Pro264Leu and Met-146Val). In this screen, we also identified the recently reported APP mutation in two siblings with AD. This mutation,named the Uppsala mutation, consists of a six amino acid intra-amyloid β deletion.In addition, we found several potentially pathogenic mutations in PSEN2, FUS, MAPT, GRN and APOE. Finally, APOE ε4was prevalent in this patient group with an allele frequency of 54%Conclusions: Among the 102 screened patients, we found two disease causing mutations in PSEN1 and one in APP,as well as several potentially pathogenic mutations in other genes related to neurodegenerative disorders. Apart fromgiving important information to the clinical investigation, the identification of disease mutations can contribute to anincreased understanding of disease mechanisms.
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