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https://www.readbyqxmd.com/read/28538692/exploring-anti-prion-glyco-based-and-aromatic-scaffolds-a-chemical-strategy-for-the-quality-of-life
#1
REVIEW
María Teresa Blázquez-Sánchez, Ana M de Matos, Amélia P Rauter
Prion diseases are fatal neurodegenerative disorders caused by protein misfolding and aggregation, affecting the brain progressively and consequently the quality of life. Alzheimer's is also a protein misfolding disease, causing dementia in over 40 million people worldwide. There are no therapeutics able to cure these diseases. Cellular prion protein is a high-affinity binding partner of amyloid β (Aβ) oligomers, the most toxic species in Alzheimer's pathology. These findings motivate the development of new chemicals for a better understanding of the events involved...
May 24, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28533388/selective-lowering-of-synapsins-induced-by-oligomeric-%C3%AE-synuclein-exacerbates-memory-deficits
#2
Megan E Larson, Susan J Greimel, Fatou Amar, Michael LaCroix, Gabriel Boyle, Mathew A Sherman, Hallie Schley, Camille Miel, Julie A Schneider, Rakez Kayed, Fabio Benfenati, Michael K Lee, David A Bennett, Sylvain E Lesné
Mounting evidence indicates that soluble oligomeric forms of amyloid proteins linked to neurodegenerative disorders, such as amyloid-β (Aβ), tau, or α-synuclein (αSyn) might be the major deleterious species for neuronal function in these diseases. Here, we found an abnormal accumulation of oligomeric αSyn species in AD brains by custom ELISA, size-exclusion chromatography, and nondenaturing/denaturing immunoblotting techniques. Importantly, the abundance of αSyn oligomers in human brain tissue correlated with cognitive impairment and reductions in synapsin expression...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28519902/reduced-gliotransmitter-release-from-astrocytes-mediates-tau-induced-synaptic-dysfunction-in-cultured-hippocampal-neurons
#3
Roberto Piacentini, Domenica Donatella Li Puma, Marco Mainardi, Giacomo Lazzarino, Barbara Tavazzi, Ottavio Arancio, Claudio Grassi
Tau is a microtubule-associated protein exerting several physiological functions in neurons. In Alzheimer's disease (AD) misfolded tau accumulates intraneuronally and leads to axonal degeneration. However, tau has also been found in the extracellular medium. Recent studies indicated that extracellular tau uploaded from neurons causes synaptic dysfunction and contributes to tau pathology propagation. Here we report novel evidence that extracellular tau oligomers are abundantly and rapidly accumulated in astrocytes where they disrupt intracellular Ca(2+) signaling and Ca(2+) -dependent release of gliotransmitters, especially ATP...
May 18, 2017: Glia
https://www.readbyqxmd.com/read/28517926/laser-induced-population-inversion-in-rhodamine-6g-for-lysozyme-oligomers-detection
#4
Piotr Hanczyc, Lech Sznitko
Fluorescence spectroscopy is a common method for detecting amyloid fibrils where organic fluorophores are used as markers that exhibit increase of the quantum yield upon binding. However, most of the dyes exhibit enhanced emission only when bound to mature fibrils and significantly weaker signals are obtained in presence of amyloid oligomers. In the concept of population inversion, laser is used as an excitation source in order to keep the major fraction of molecules in the excited state to create the pathways for stimulated emission occurrence...
May 18, 2017: Biochemistry
https://www.readbyqxmd.com/read/28509424/inhibition-of-prion-propagation-by-3-4-dimethoxycinnamic-acid
#5
Ivan Zanyatkin, Yulia Stroylova, Sofia Tishina, Victor Stroylov, Aleksandra Melnikova, Thomas Haertle, Vladimir Muronetz
Neurodegenerative diseases are associated with accumulation of amyloid-type protein misfolding products. Prion protein (PrP) is known for its ability to aggregate into soluble oligomers that in turn associate into amyloid fibrils. Preventing the formation of these infective and neurotoxic entities represents a viable strategy to control prion diseases. Numerous attempts to find dietary compounds with anti-prion properties have been made; however, the most promising agent found so far was curcumin, which is poorly soluble and merely bioavailable...
May 16, 2017: Phytotherapy Research: PTR
https://www.readbyqxmd.com/read/28509380/amyloid-is-essential-but-insufficient-for-alzheimer-causation-addition-of-subcellular-cofactors-is-required-for-dementia
#6
REVIEW
Jeffrey Fessel
OBJECTIVE: The aim of this study is to examine the hypotheses stating the importance of amyloid or of its oligomers in the pathogenesis of Alzheimer's disease (AD). METHODS: Published studies were examined. RESULTS: The importance of amyloid in the pathogenesis of AD is well established, yet accepting it as the main cause for AD is problematic, because amyloid-centric treatments have provided no clinical benefit and about one-third of cognitively normal, older persons have cerebral amyloid plaques...
May 16, 2017: International Journal of Geriatric Psychiatry
https://www.readbyqxmd.com/read/28500395/the-human-serum-protein-c4b-binding-protein-inhibits-pancreatic-iapp-induced-inflammasome-activation
#7
Klaudia Kulak, Gunilla T Westermark, Nikolina Papac-Milicevic, Erik Renström, Anna M Blom, Ben C King
AIMS/HYPOTHESIS: Inflammasome activation and subsequent IL-1β production is a driver of islet pathology in type 2 diabetes. Oligomers, but not mature amyloid fibrils, of human islet amyloid polypeptide (IAPP), which is co-secreted with insulin, trigger NOD-like receptor pyrin domain containing-3 (NLRP3) inflammasome activation. C4b-binding protein (C4BP), present in serum, binds to IAPP and affects transition of IAPP monomers and oligomers to amyloid fibrils. We therefore hypothesised that C4BP inhibits IAPP-mediated inflammasome activation and IL-1β production...
May 12, 2017: Diabetologia
https://www.readbyqxmd.com/read/28499970/chitinase1-contributed-to-a-potential-protection-via-microglia-polarization-and-a%C3%AE-oligomer-reduction-in-d-galactose-and-aluminum-induced-rat-model-with-cognitive-impairments
#8
Qian Xiao, Weihua Yu, Qi Tian, Xue Fu, Xia Wang, Min Gu, Yang Lü
Chitinase activity is increased in Alzheimer's disease (AD). However, the role of chitinase1 in AD is unknown. We investigated the effects of chitinase1 on Alzheimer's pathology and microglia function. Artificial chitinase1 and chitinase inhibitor (chitinase-IN-2) were used to determine the effects of chitinase1 on inflammatory factors and β-amyloid (Aβ) oligomers deposition in D-galactose/AlCl3-induced rat model with cognitive impairments. Aβ-treated N9 microglia cells were analyzed to further verify whether the changes in inflammatory factors following chitinase1 treatment were associated with microglia alternative activation...
May 10, 2017: Neuroscience
https://www.readbyqxmd.com/read/28495735/a-more-pathological-amyloid-%C3%AE-oligomer
#9
EDITORIAL
Leslie K Ferrarelli
No abstract text is available yet for this article.
May 12, 2017: Science
https://www.readbyqxmd.com/read/28488564/hippocampal-cholinergic-neurostimulating-peptide-as-a-possible-modulating-factor-against-glutamatergic-neuronal-disability-by-amyloid-oligomers
#10
Toyohiro Sato, Yoshiaki Ohi, Daisuke Kato, Masayuki Mizuno, Hiroshi Takase, Tetsuko Kanamori, Cesar V Borlongan, Akira Haji, Noriyuki Matsukawa
Despite having pathological changes in the brain associated Alzheimer's disease (AD), some patients have preserved cognitive function. A recent epidemiological study has shown that diet, exercise, cognitive training, and vascular risk monitoring interventions may reduce cognitive decline in at-risk elderly people in the general population. However, the details of molecular mechanisms underlying this cognitive function preservation are still unknown. Previous report demonstrated that enriched environments prevent the impairment of hippocampal long-term potentiation (LTP) through β2-adrenergic signals, when LTP is incompletely suppressed by synthetic amyloid-β (Aβ) oligomers...
May 9, 2017: Cell Transplantation
https://www.readbyqxmd.com/read/28487634/ryr2-mediated-ca-2-release-and-mitochondrial-ros-generation-partake-in-the-synaptic-dysfunction-caused-by-amyloid-%C3%AE-peptide-oligomers
#11
Carol D SanMartín, Pablo Veloso, Tatiana Adasme, Pedro Lobos, Barbara Bruna, Jose Galaz, Alejandra García, Steffen Hartel, Cecilia Hidalgo, Andrea C Paula-Lima
Amyloid β peptide oligomers (AβOs), toxic aggregates with pivotal roles in Alzheimer's disease, trigger persistent and low magnitude Ca(2+) signals in neurons. We reported previously that these Ca(2+) signals, which arise from Ca(2+) entry and subsequent amplification by Ca(2+) release through ryanodine receptor (RyR) channels, promote mitochondrial network fragmentation and reduce RyR2 expression. Here, we examined if AβOs, by inducing redox sensitive RyR-mediated Ca(2+) release, stimulate mitochondrial Ca(2+)-uptake, ROS generation and mitochondrial fragmentation, and also investigated the effects of the antioxidant N-acetyl cysteine (NAC) and the mitochondrial antioxidant EUK-134 on AβOs-induced mitochondrial dysfunction...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28487416/the-amyloid-%C3%AE-oligomer-a%C3%AE-56-induces-specific-alterations-in-neuronal-signaling-that-lead-to-tau-phosphorylation-and-aggregation
#12
Fatou Amar, Mathew A Sherman, Travis Rush, Megan Larson, Gabriel Boyle, Liu Chang, Jürgen Götz, Alain Buisson, Sylvain E Lesné
Oligomeric forms of amyloid-forming proteins are believed to be the principal initiating bioactive species in many neurodegenerative disorders, including Alzheimer's disease (AD). Amyloid-β (Aβ) oligomers are implicated in AD-associated phosphorylation and aggregation of the microtubule-associated protein tau. To investigate the specific molecular pathways activated by different assemblies, we isolated various forms of Aβ from Tg2576 mice, which are a model for AD. We found that Aβ*56, a 56-kDa oligomer that is detected before patients develop overt signs of AD, induced specific changes in neuronal signaling...
May 9, 2017: Science Signaling
https://www.readbyqxmd.com/read/28487367/insights-into-the-mechanism-of-cystatin-c-oligomer-and-amyloid-formation-and-its-interaction-with-beta-amyloid
#13
Tyler J Perlenfein, Jacob D Mehlhoff, Regina M Murphy
Cystatin C (CysC) is a versatile and ubiquitously-expressed member of the cysteine protease inhibitor family that is present at notably high concentration in cerebrospinal fluid. Under mildly denaturing conditions, CysC forms inactive domain-swapped dimers. A destabilizing mutation, L68Q, increases the rate of domain-swapping and causes a fatal amyloid disease, Hereditary Cystatin C Amyloid Angiopathy. Wild-type (wt) CysC will also aggregate into amyloid fibrils under some conditions. Propagated domain swapping has been proposed as the mechanism by which CysC fibrils grow...
May 9, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28482661/insights-into-formation-and-structure-of-a%C3%AE-oligomers-cross-linked-via-tyrosines
#14
Shuting Zhang, Dillion M Fox, Brigita Urbanc
Alzheimer's disease (AD) pathology is hypothesized to be triggered by amyloid β-protein (Aβ) assembly into oligomers. Oligomer size distributions of both predominant Aβ alloforms, Aβ40 and Aβ42, can be determined in vitro using cross-linking followed by gel electrophoresis. Cross-linking, which can occur in vivo in the presence of copper and hydrogen peroxide, was recently shown to stabilize Aβ oligomers by inhibiting their conversion into fibrils. Whereas several studies showed that cross-linking is facilitated by dityrosine bond formation, the molecular-level mechanism of cross-linking remains unclear...
May 23, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28482635/the-anti-amyloid-%C3%AE-and-neuroprotective-properties-of-a-novel-tricyclic-pyrone-molecule
#15
Izumi Maezawa, Bende Zou, Jacopo Di Lucente, William S Cao, Conrado Pascual, Sahani Weerasekara, Man Zhang, Xinmin Simon Xie, Duy H Hua, Lee-Way Jin
There is an urgent unmet need for new therapeutics for Alzheimer's disease (AD), the most common cause of dementia in the elderly. Therapeutic approaches targeting amyloid-β (Aβ) and its downstream toxicities have become major strategies in AD drug development. We have taken a rational design approach and synthesized a class of tricyclic pyrone (TP) compounds that show anti-Aβ and other neuroprotective actions. The in vivo efficacy of a lead TP named CP2 to ameliorate AD-like pathologies has been shown in mouse models...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28478680/fucoxanthin-inhibits-%C3%AE-amyloid-assembly-and-attenuates-%C3%AE-amyloid-oligomer-induced-cognitive-impairments
#16
Siying Xiang, Fufeng Liu, Jiajia Lin, Huixin Chen, Chunhui Huang, Liping Chen, Yiying Zhou, Luying Ye, Ke Zhang, Jiukai Jin, Jiacheng Zhen, Chuang Wang, Shan He, Qinwen Wang, Wei Cui, Jinrong Zhang
β-Amyloid (Aβ) can form aggregates through self-assembly and produce neurotoxicity in the early stage of Alzheimer's disease (AD). Therefore, the inhibition of Aβ assembly is considered as the primary target for AD therapy. In this study, we reported that fucoxanthin, a marine carotenoid, potently reduced the formation of Aβ fibrils and oligomers. Moreover, the fucoxanthin-triggered modification significantly reduced the neurotoxicity of Aβ oligomers in vitro. Molecular dynamics simulation analysis further revealed a hydrophobic interaction between fucoxanthin and Aβ peptide, which might prevent the conformational transition and self-assembly of Aβ...
May 11, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28473749/amyloid-%C3%AE-exposed-human-astrocytes-overproduce-phospho-tau-and-overrelease-it-within-exosomes-effects-suppressed-by-calcilytic-nps-2143-further-implications-for-alzheimer-s-therapy
#17
Anna Chiarini, Ubaldo Armato, Emanuela Gardenal, Li Gui, Ilaria Dal Prà
The two main drivers of Alzheimer's disease (AD), amyloid-β (Aβ) and hyperphosphorylated Tau (p-Tau) oligomers, cooperatively accelerate AD progression, but a hot debate is still ongoing about which of the two appears first. Here we present preliminary evidence showing that Tau and p-Tau are expressed by untransformed cortical adult human astrocytes in culture and that exposure of such cells to an Aβ42 proxy, Aβ25-35, which binds the calcium-sensing receptor (CaSR) and activates its signaling, significantly increases intracellular p-Tau levels, an effect CaSR antagonist (calcilytic) NPS 2143 wholly hinders...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28472188/a-prion-like-mechanism-for-the-propagated-misfolding-of-sod1-from-in-silico-modeling-of-solvated-near-native-conformers
#18
Eamonn F Healy
A prion-like mechanism has been developed to explain the observed promotion of amyloid aggregation caused by conversion of structurally intact SOD1 to a misfolded form. Superoxide dismutase [Cu-Zn], or SOD1, is a homo-dimeric protein that functions as an antioxidant by scavenging for superoxide. The misfolding and aggregation of SOD1 is linked to inherited, or familial, amyotrophic lateral sclerosis (FALS), a progressive and fatal neurodegenerative disease. Aberrant SOD1 folding has also been strongly implicated in disease causation for sporadic ALS, or SALS, which accounts for ~90% of ALS cases...
2017: PloS One
https://www.readbyqxmd.com/read/28469550/exosomes-and-the-prion-protein-more-than-one-truth
#19
REVIEW
Alexander Hartmann, Christiane Muth, Oliver Dabrowski, Susanne Krasemann, Markus Glatzel
Exosomes are involved in the progression of neurodegenerative diseases. The cellular prion protein (PrP(C)) is highly expressed on exosomes. In neurodegenerative diseases, PrP(C) has at least two functions: It is the substrate for the generation of pathological prion protein (PrP(Sc)), a key player in the pathophysiology of prion diseases. On the other hand, it binds neurotoxic amyloid-beta (Aß) oligomers, which are associated with initiation and progression of Alzheimer's disease (AD). This has direct consequences for the role of exosomal expressed PrP(C)...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28468825/small-molecule-mediated-inhibition-of-%C3%AE-2-microglobulin-amyloid-fibril-formation
#20
Tyler M Marcinko, Jia Dong, Raquel LeBlanc, Kate V Daborowski, Richard W Vachet
In dialysis patients, β-2 microglobulin (β2m) can aggregate and eventually form amyloid fibrils in a condition known as dialysis-related amyloidosis, which deleteriously affects joint and bone function. Recently, several small molecules have been identified as potential inhibitors of β2m amyloid formation in vitro. Here, we investigate if these molecules are more broadly applicable inhibitors of β2m amyloid formation by studying their effect on Cu(II)-induced β2m amyloid formation. Using a variety of biophysical techniques, we also examine their inhibitory mechanisms...
May 3, 2017: Journal of Biological Chemistry
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