| 1. |
- Wagner, Leona, et al.
(författare)
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Neuropeptide Y (NPY) in cerebrospinal fluid from patients with Huntington's Disease : increased NPY levels and differential degradation of the NPY1-30 fragment
- 2016
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 137:5, s. 820-837
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Tidskriftsartikel (refereegranskat)abstract
- Huntington's disease (HD) is an inherited and fatal polyglutamine neurodegenerative disorder caused by an expansion of the CAG triplet repeat coding region within the HD gene. Progressive dysfunction and loss of striatal GABAergic medium spiny neurons (MSNs) may account for some of the characteristic symptoms in HD patients. Interestingly, in HD, MSNs expressing neuropeptide Y (NPY) are spared and their numbers is even up-regulated in HD patients. In line with this, we report here on increased immuno-linked NPY (IL-NPY) levels in human cerebrospinal fluid (hCSF) from HD patients. As this antibody-based detection of NPY may provide false positive differences due to the antibody-based detections of only fragments of NPY, the initial finding was validated by investigating the proteolytic stability of NPY in hCSF using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and selective inhibitors. A comparison between resulting NPY-fragments and detailed epitope analysis verified significant differences of IL-NPY1-36/3-36 and NPY1-30 levels between HD patients and control subjects. Ex vivo degradomics analysis demonstrated that NPY is initially degraded to NPY1-30 by cathepsin D (CTSD) in both HD patients and control subjects. Yet, NPY1-30 is then further differentially hydrolyzed by thimet oligopeptidase (TOP) in HD patients and by neprilysin (NEP) in control subjects. Furthermore, altered hCSF TOP-inhibitor Dynorphin A1-13 (Dyn-A1-13 ) and TOP-substrate Dyn-A1-8 levels indicate an impaired Dyn-A-TOP network in HD patients. Thus, we conclude that elevated IL-NPY-levels in conjunction with TOP- / NEP-activity/protein as well as Dyn-A1-13 -protein levels may serve as a potential biomarker in human CSF of HD. This article is protected by copyright. All rights reserved.
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| 2. |
- Wagner, Leona, et al.
(författare)
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Proteolytic degradation of neuropeptide Y (NPY) from head to toe: Identification of novel NPY-cleaving peptidases and potential drug interactions in CNS and Periphery.
- 2015
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 135:5, s. 1019-1037
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Tidskriftsartikel (refereegranskat)abstract
- The bioactivity of neuropeptide Y (NPY) is either N-terminally modulated with respect to receptor-selectivity by dipeptidyl-peptidase 4 (DP4)-like enzymes or proteolytic degraded by neprilysin or meprins, thereby abrogating signal transduction. However, neither the subcellular nor the compartmental differentiation of these regulatory mechanisms is fully understood. Using mass spectrometry, selective inhibitors and histochemistry, studies across various cell types, body fluids and tissues revealed that most frequently DP4-like enzymes, aminopeptidases P (AmpP), secreted meprin-A (Mep-A) and cathepsin D (CTSD) rapidly hydrolyze NPY, depending on the cell type and tissue under study. Novel degradation of NPY by cathepsins B, D, L, G, S and tissue kallikrein could also be identified. Expression of DP4, CTSD, and Mep-A at the median eminence indicates that the bioactivity of NPY is regulated by peptidases at the interphase between the periphery and the CNS. Detailed ex vivo studies on human sera and CSF samples recognized CTSD as the major NPY-cleaving enzyme in the CSF, whereas an additional C-terminal truncation by angiotensin-converting enzyme (ACE) could be detected in serum. The latter finding hints to potential drug interaction between antidiabetic DP4 inhibitors and anti-hypertensive ACE inhibitors, while it ablates suspected hypertensive side-effects of only antidiabetic DP4-inhibitors application. This article is protected by copyright. All rights reserved.
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| 3. |
- Joshi, Peter K, et al.
(författare)
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Directional dominance on stature and cognition in diverse human populations
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523:7561, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.
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| 4. |
- Wittnam, Jessica L, et al.
(författare)
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Pyroglutamate amyloid β (Aβ) aggravates behavioral deficits in transgenic amyloid mouse model for Alzheimer disease.
- 2012
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Ingår i: The Journal of biological chemistry. - 1083-351X. ; 287:11, s. 8154-62
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Tidskriftsartikel (refereegranskat)abstract
- Pyroglutamate-modified Aβ peptides at amino acid position three (Aβ(pE3-42)) are gaining considerable attention as potential key players in the pathogenesis of Alzheimer disease (AD). Aβ(pE3-42) is abundant in AD brain and has a high aggregation propensity, stability and cellular toxicity. The aim of the present work was to study the direct effect of elevated Aβ(pE3-42) levels on ongoing AD pathology using transgenic mouse models. To this end, we generated a novel mouse model (TBA42) that produces Aβ(pE3-42). TBA42 mice showed age-dependent behavioral deficits and Aβ(pE3-42) accumulation. The Aβ profile of an established AD mouse model, 5XFAD, was characterized using immunoprecipitation followed by mass spectrometry. Brains from 5XFAD mice demonstrated a heterogeneous mixture of full-length, N-terminal truncated, and modified Aβ peptides: Aβ(1-42), Aβ(1-40), Aβ(pE3-40), Aβ(pE3-42), Aβ(3-42), Aβ(4-42), and Aβ(5-42). 5XFAD and TBA42 mice were then crossed to generate transgenic FAD42 mice. At 6 months of age, FAD42 mice showed an aggravated behavioral phenotype compared with single transgenic 5XFAD or TBA42 mice. ELISA and plaque load measurements revealed that Aβ(pE3) levels were elevated in FAD42 mice. No change in Aβ(x)(-42) or other Aβ isoforms was discovered by ELISA and mass spectrometry. These observations argue for a seeding effect of Aβ(pE-42) in FAD42 mice.
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