Search results for "amyloid beta-peptides"
showing 10 items of 131 documents
Naturally occurring autoantibodies interfere with β-amyloid metabolism and improve cognition in a transgenic mouse model of Alzheimer's disease 24 h …
2013
There is evidence that naturally occurring antibodies directed against Aβ (nAbs-Aβ) have a role in Aβ-metabolism and Aβ-clearance. The presence of nAbs-Aβ leads to a reduction in amyloid fibrillation and thus a reduction in their toxicity. We investigated the effects of nAbs-Aβ in respect to oligomerization and used the Tg2576 transgenic mouse model in order to investigate the rapid effect with a single-dose (24 h) on oligomer breakdown and cytokine secretion along with immunohistochemical characterization of synaptic plasticity. nAbs-Aβ were able to reduce toxic oligomer concentration with an increase in Aβ-monomers. Cytokine secretion was significantly reduced. Synaptic plasticity was als…
Physical exercise in the prevention and treatment of Alzheimer's disease
2020
Highlights • Low levels of physical activity are a risk factor associated with Alzheimer's disease. • Older adults who exercise are more likely to maintain cognition. • Exercise modulates amyloid β turnover, inflammation, synthesis, and release of neurotrophins, and cerebral blood flow.
LRP1 modulates APP trafficking along early compartments of the secretory pathway
2008
The amyloid beta peptide (A beta) is a central player in Alzheimer's disease (AD) pathology. A beta liberation depends on APP cleavage by beta- and gamma-secretases. The low density lipoprotein receptor related protein 1 (LRP1) was shown to mediate APP processing at multiple steps. Newly synthesized LRP1 can interact with APP, implying an interaction between these two proteins early in the secretory pathway. We wanted to investigate whether LRP1 mediates APP trafficking along the secretory pathway, and, if so, whether it affects APP processing. Indeed, the early trafficking of APP within the secretory pathway is strongly influenced by its interaction with the C-terminal domain of LRP1. The …
Neuronal activity and secreted amyloid β lead to altered amyloid β precursor protein and presenilin 1 interactions.
2013
Deposition of amyloid β (Aβ) containing plaques in the brain is one of the neuropathological hallmarks of Alzheimer's disease (AD). It has been suggested that modulation of neuronal activity may alter Aβ production in the brain. We postulate that these changes in Aβ production are due to changes in the rate-limiting step of Aβ generation, APP cleavage by γ-secretase. By combining biochemical approaches with fluorescence lifetime imaging microscopy, we found that neuronal inhibition decreases endogenous APP and PS1 interactions, which correlates with reduced Aβ production. By contrast, neuronal activation had a two-phase effect: it initially enhanced APP-PS1 interaction leading to increased …
Action of low doses of Aspirin in Inflammation and Oxidative Stress induced by aβ
2019
Aspirin has been used as anti-inflammatory and anti-aggregate for decades but the precise mechanism(s) of action after the presence of the toxic peptide Aβ1-42 in cultured astrocytes remains poorly resolved. Here we use low-doses of aspirin (10-7 M) in astrocytes in primary culture in presence or absence of Aβ1-42 toxic peptide. We noted an increase of cell viability and proliferation with or without Aβ1-42 peptide presence in aspirin treated cells. In addition, a decrease in apoptosis, determined by Caspase 3 activity and the expression of Cyt c and Smac/Diablo, were detected. Also, aspirin diminished necrosis process (LDH levels), pro-inflammatory mediators (IL-β and TNF-α) and NF-ᴋB prot…
A New Tool for the Analysis of the Effect of Intracerebrally Injected Anti-Amyloid-β Compounds
2021
Background: A wide range of techniques has been developed over the past decades to characterize amyloid-β (Aβ) pathology in mice. Until now, no method has been established to quantify spatial changes in Aβ plaque deposition due to targeted delivery of substances using ALZET® pumps. Objective: Development of a methodology to quantify the local distribution of Aβ plaques after intracerebral infusion of compounds. Methods: We have developed a toolbox to quantify Aβ plaques in relation to intracerebral injection channels using Zeiss AxioVision® and Microsoft Excel® software. For the proof of concept, intracerebral stereotactic surgery was performed in 50-day-old APP-transgenic mice injected wit…
Oestradiol or genistein rescues neurons from amyloid beta-induced cell death by inhibiting activation of p38.
2007
Oestrogenic compounds have been postulated as neuroprotective agents. This prompted us to investigate their mechanism action in neurons in primary culture. Cells were pretreated with physiological concentrations of 17-beta estradiol (0.2 nm) or with nutritionally relevant concentrations of genistein (0.5 microm), and 48 h later treated with 5 microm of amyloid beta (Abeta) for 24 h. We found that Abeta increased oxidative stress, measured as peroxide levels or oxidized glutathione/reduced glutathione ratio, which in turn, caused phosphorylation of p38 MAP kinase. Amyloid beta subsequently induced neuronal death. Inhibiting the MAP kinase pathway prevented cell death, confirming the role of …
Garcinoic acid prevents β-amyloid (Aβ) deposition in the mouse brain
2020
Garcinoic acid (GA or δ-T3-13'COOH), is a natural vitamin E metabolite that has preliminarily been identified as a modulator of nuclear receptors involved in β-amyloid (Aβ) metabolism and progression of Alzheimer's disease (AD). In this study, we investigated GA's effects on Aβ oligomer formation and deposition. Specifically, we compared them with those of other vitamin E analogs and the soy isoflavone genistein, a natural agonist of peroxisome proliferator–activated receptor γ (PPARγ) that has therapeutic potential for managing AD. GA significantly reduced Aβ aggregation and accumulation in mouse cortical astrocytes. Similarly to genistein, GA up-regulated PPARγ expression and apolipoprote…
Memory-enhancing and brain protein expression-stimulating effects of novel calcium antagonist in Alzheimer’s disease transgenic female mice
2016
The prevalence of Alzheimer's disease (AD) is higher in females than in males, and causes more severe cognitive, memory and behavioral impairments. Previously, in male transgenic (Tg) APPSweDI mice, we reported that the novel lipophilic 1,4-dihydropyridine (DHP) derivative AP-12 crossed the blood-brain barrier, blocked neuronal and vascular calcium channels, changed brain protein expression and improved behavior. In this study, we used female Tg APPSweDI mice to assess the effects of AP-12 on behavior, and brain protein expression, with a particular focus on those of the GABAergic system. The results showed that in female Tg mice, similar to male Tg mice, AP-12 improved spatial learning/mem…
Exercise and probiotics attenuate the development of Alzheimer's disease in transgenic mice: Role of microbiome
2018
Abstract It has been suggested that exercise training and probiotic supplementation could decelerate the progress of functional and biochemical deterioration in APP/PS1 transgenic mice (APP/PS1TG). APP/PS1TG mice were subjected to exercise training and probiotic treatments and functional, biochemical and microbiome markers were analyzed. Under these conditions the mice significantly outperformed controls on The Morris Maze Test, and the number of beta-amyloid plaques decreased in the hippocampus. B. thetaiotaomicron levels correlated highly with the results of the Morris Maze Test (p