| 1. |
- Ingelsson, Martin, et al.
(författare)
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Increase in the relative expression of tau with four microtubule binding repeat regions in frontotemporal lobar degeneration and progressive supranuclear palsy brains
- 2007
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 114:5, s. 471-479
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Tidskriftsartikel (refereegranskat)abstract
- Some cases of familial frontotemporal dementia (FTD) leading to frontotemporal lobar degeneration (FTLD) are caused by mutations in tau on chromosome 17 (FTDP-17). Certain mutations alter the ratio between four (4R tau) and three (3R tau) repeat tau isoforms whereas cases with progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) mainly have 4R tau brain pathology. We assessed tau mRNA and protein levels in frontal cortex from 15 sporadic FTLD, 21 PSP, 5 CBD, 15 Alzheimer’s disease (AD) and 16 control brains. Moreover, we investigated the disease association and possible tau splicing effects of the tau H1 haplotype. Cases with FTLD and PSP had lower tau mRNA levels than control brains. When analyzing 4R tau and 3R tau mRNA separately, control subjects displayed a 4R tau/3R tau ratio of 0.48. Surprisingly, FTLD brains displayed a more elevated ratio (1.32) than PSP brains (1.12). Also, several FTLD and PSP cases had higher 4R tau/3R tau mRNA than FTDP-17 cases, included as reference tissues, and the ratio increase was seen regardless of underlying histopathology, i.e. both for tau-positive and tau-negative FTLD cases. Furthermore, total tau protein levels were slightly decreased in both FTLD and AD as compared to control subjects. Finally, we confirmed the association of tau H1 with PSP, but could not find any haplotype-related effect on tau exon 10 splicing. In conclusion, we demonstrated increased but largely variable 4R tau/3R tau mRNA ratios in FTLD and PSP cases, suggesting heterogeneous pathophysiological processes within these disorders.
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| 2. |
- Ingelsson, Martin, et al.
(författare)
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No alteration in tau exon 10 alternative splicing in tangle-bearing neurons of the Alzheimer's disease brain
- 2006
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 112:4, s. 439-449
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Tidskriftsartikel (refereegranskat)abstract
- Defective splicing of tau mRNA, promoting a shift between tau isoforms with (4R tau) and without (3R tau) exon 10, is believed to be a pathological consequence of certain tau mutations causing frontotemporal dementia. By assessing protein and mRNA levels of 4R tau and 3R tau in 27 AD and 20 control temporal cortex, we investigated whether altered tau splicing is a feature also in Alzheimer's disease (AD). However, apart from an expected increase of sarcosyl-insoluble tau in AD, there were no significant differences between the groups. Next, by laser-capture microscopy and quantitative PCR, we separately analyzed CA1 hippocampal neurons with and without neurofibrillary pathology from six of the AD and seven of the control brains. No statistically significant differences in 4R tau/3R tau mRNA were found between the different subgroups. Moreover, we confirmed the absence of significant ratio differences in a second data set with laser-captured entorhinal cortex neurons from four AD and four control brains. Finally, the 4R tau/3R tau ratio in CA1 neurons was roughly half of the ratio in temporal cortex, indicating region-specific differences in tau mRNA splicing. In conclusion, this study indicated region-specific and possibly cell-type-specific tau splicing but did not lend any support to overt changes in alternative splicing of tau exon 10 being an underlying factor in AD pathogenesis.
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| 3. |
- Kim, Minji, et al.
(författare)
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Decreased catalytic activity of the insulin-degrading enzyme in chromosome 10-linked Alzheimer disease families
- 2007
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 282:11, s. 7825-7832
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-degrading enzyme (IDE) is a zinc metalloprotease that degrades the amyloid beta-peptide, the key component of Alzheimer disease (AD)-associated senile plaques. We have previously reported evidence for genetic linkage and association of AD on chromosome 10q23-24 in the region harboring the IDE gene. Here we have presented the first functional assessment of IDE in AD families showing the strongest evidence of the genetic linkage. We have examined the catalytic activity and expression of IDE in lymphoblast samples from 12 affected and unaffected members of three chromosome 10-linked AD pedigrees in the National Institute of Mental Health AD Genetics Initiative family sample. We have shown that the catalytic activity of cytosolic IDE to degrade insulin is reduced in affected versus unaffected subjects of these families. Further, we have shown the decrease in activity is not due to reduced IDE expression, suggesting the possible defects in IDE function in these AD families. In attempts to find potential mutations in the IDE gene in these families, we have found no coding region substitutions or alterations in splicing of the canonical exons and exon 15b of IDE. We have also found that total IDE mRNA levels are not significantly different in sporadic AD versus age-matched control brains. Collectively, our data suggest that the genetic linkage of AD in this set of chromosome 10-linked AD families may be the result of systemic defects in IDE activity in the absence of altered IDE expression, further supporting a role for IDE in AD pathogenesis.
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| 4. |
- Matsui, Toshifumi, et al.
(författare)
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Expression of APP pathway mRNAs and proteins in Alzheimer's disease
- 2007
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Ingår i: Brain Research. - : Elsevier BV. - 0006-8993 .- 1872-6240. ; 1161, s. 116-123
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Tidskriftsartikel (refereegranskat)abstract
- In both trisomy 21 and rare cases of triplication of amyloid precursor protein (APP) Alzheimer's disease (AD) pathological changes are believed to be secondary to increased expression of APP. We hypothesized that sporadic AD may also be associated with changes in transcription of APP or its metabolic partners. To address this issue, temporal neocortex of 27 AD and 21 non-demented control brains was examined to assess mRNA levels of APP isoforms (total APP, APP containing the Kunitz protease inhibitor domain [APP-KPI] and APP770) and APP metabolic enzymatic partners (the APP cleaving enzymes beta-secretase [BACE] and presenilin-1 [PS- 1], and putative clearance molecules, low-density lipoprotein receptor protein [LRP] and apolipoprotein E [apoE]). Furthermore, we evaluated how changes in APP at the mRNA level affect the amount of Tris buffer extractable APP protein and A beta 40 and 42 peptides in AD and control brains. As assessed by quantitative PCR, APP-KPI (p=0.007), APP770 (p=0.004), PS-1 (p = 0.004), LRP (p = 0.003), apoE (p = 0.0002) and GFAP (p < 0.0001) mRNA levels all increased in AD, and there was a shift from APP695 (a neuronal isoform) towards KPI containing isoforms that are present in glia as well. APP-KPI mRNA levels correlated with soluble APP alpha -KPI protein (sAPP alpha -KPI) levels measured by ELISA (T= 0.33, p = 0.015 by Kendall's rank correlation); in turn, soluble APP alpha-KPI protein levels positively correlated with Tris -extractable, soluble A beta 40 (p=0.046) and 42 levels (p=0.007). The ratio of soluble APP alpha-KPI protein levels to total APP protein increased in AD, and also correlated with GFAP protein levels in AD. These results suggest that altered transcription of APP in AD is proportionately associated with A beta peptide, may occur in the context of gliosis, and may contribute to A beta deposition in sporadic AD.
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| 5. |
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| 6. |
- Skoglund, Lena, et al.
(författare)
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No evidence of PGRN or MAPT gene dosage alterations in a collection of patients with frontotemporal lobar degeneration
- 2009
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 28:5, s. 471-475
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims Alterations in gene dosage have recently been associated with neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, and deletions of the progranulin (PGRN) locus were recently described in patients with frontotemporal lobar degeneration (FTLD). FTLD is a genetically complex neurodegenerative disorder with mutations in the PGRN and the microtubule-associated protein tau (MAPT) genes being the most common known causes of familial FTLD. In this study, we investigated 39 patients with FTLD, previously found negative for mutations in PGRN and MAPT, for copy number alterations of these 2 genes. Methods Gene dosage analysis of PGRN and MAPT was performed using multiplex ligation-dependent probe amplification. Results We did not identify any PGRN or MAPT gene dosage variations in the 39 FTLD patients investigated. Conclusion We therefore conclude that alterations in gene copy number of PGRN and MAPT are not a cause of disease in this ollection of FTLD patients.
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| 7. |
- Skoglund, Lena, et al.
(författare)
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Novel Progranulin Mutation Detected in 2 Patients With FTLD
- 2011
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Ingår i: Alzheimer Disease and Associated Disorders. - : Lippincott Williams & Wilkins. - 0893-0341 .- 1546-4156. ; 25:2, s. 173-178
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Tidskriftsartikel (refereegranskat)abstract
- Frontotemporal lobar degeneration (FTLD) with ubiquitin-positive, tau-negative inclusions, and linkage to chromosome 17 was recently found to be caused by mutations in the progranulin (PGRN) gene. In this study, we screened a group of 51 FTLD patients for PGRN mutations and identified a novel exon 6 splice donor site deletion (IVS6+5_8delGTGA) in 2 unrelated patients. This mutation displayed an altered splicing pattern generating 2 aberrant transcripts and causing frameshifts of the coding sequence, premature termination codons, and a near absence of PGRN mRNA from the mutated alleles most likely through nonsense-mediated decay. The subsequent PGRN haploinsufficiency is consistent with previously described PGRN mutations. We present a molecular characterization of the IVS6+5_8delGTGA mutation and also describe clinical and neuropathologic features from the 2 patients carrying this PGRN mutation. From the screening of these 51 FTLD patients, we could also identify the earlier reported mutation Gln130fs, and several coding sequence variants that are most likely nonpathogenic.
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