keyword
MENU ▼
Read by QxMD icon Read
search

amyloid oligomer

keyword
https://www.readbyqxmd.com/read/28448032/a-tailored-hplc-purification-protocol-that-yields-high-purity-amyloid-beta-42-and-amyloid-beta-40-peptides-capable-of-oligomer-formation
#1
Christopher J A Warner, Subrata Dutta, Alejandro R Foley, Jevgenij A Raskatov
Amyloidogenic peptides such as the Alzheimer's disease-implicated Amyloid beta (Aβ), can present a significant challenge when trying to obtain high purity material. Here we present a tailored HPLC purification protocol to produce high-purity amyloid beta 42 (Aβ42) and amyloid beta 40 (Aβ40) peptides. We have found that the combination of commercially available hydrophobic poly(styrene/divinylbenzene) stationary phase, polymer laboratory reverse phase - styrenedivinylbenzene (PLRP-S) under high pH conditions, enables the attainment of high purity (>95%) Aβ42 in a single chromatographic run...
March 27, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28445751/curcumin-dictates-divergent-fates-for-the-central-salt-bridges-in-amyloid-%C3%AE-40-and-amyloid-%C3%AE-42
#2
Bappaditya Chandra, Venus Singh Mithu, Debanjan Bhowmik, Anand Kant Das, Bankanidhi Sahoo, Sudipta Maiti, Perunthiruthy K Madhu
There are three specific regions in the Amyloid beta (Aβ) peptide sequence where variations cause enhanced toxicity in Alzheimer's disease: the N-terminus, the central salt bridge, and the C-terminus. Here, we investigate if there is a close conformational connection between these three regions, which may suggest a concerted mechanism of toxicity. We measure the effects of Zn(2+) and curcumin on Aβ40, and compare these with their previously reported effects on Aβ42. Aβ42 and Aβ40 differ only near the C-terminus, where curcumin interacts, while Zn(2+) interacts near the N-terminus...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28441058/protein-misfolding-diseases
#3
F Ulrich Hartl
The majority of protein molecules must fold into defined three-dimensional structures to acquire functional activity. However, protein chains can adopt a multitude of conformational states, and their biologically active conformation is often only marginally stable. Metastable proteins tend to populate misfolded species that are prone to forming toxic aggregates, including soluble oligomers and fibrillar amyloid deposits, which are linked with neurodegeneration in Alzheimer and Parkinson disease, and many other pathologies...
April 24, 2017: Annual Review of Biochemistry
https://www.readbyqxmd.com/read/28435985/elucidating-the-a%C3%AE-42-anti-aggregation-mechanism-of-action-of-tramiprosate-in-alzheimer-s-disease-integrating-molecular-analytical-methods-pharmacokinetic-and-clinical-data
#4
Petr Kocis, Martin Tolar, Jeremy Yu, William Sinko, Soumya Ray, Kaj Blennow, Howard Fillit, John A Hey
BACKGROUND: Amyloid beta (Aβ) oligomers play a critical role in the pathogenesis of Alzheimer's disease (AD) and represent a promising target for drug development. Tramiprosate is a small-molecule Aβ anti-aggregation agent that was evaluated in phase III clinical trials for AD but did not meet the primary efficacy endpoints; however, a pre-specified subgroup analysis revealed robust, sustained, and clinically meaningful cognitive and functional effects in patients with AD homozygous for the ε4 allele of apolipoprotein E4 (APOE4/4 homozygotes), who carry an increased risk for the disease...
April 24, 2017: CNS Drugs
https://www.readbyqxmd.com/read/28429536/%C3%AE-mangostin-decreases-%C3%AE-amyloid-peptides-production-via-modulation-of-amyloidogenic-pathway
#5
Lan-Xue Zhao, Yan Wang, Ting Liu, Yan-Xia Wang, Hong-Zhuan Chen, Jian-Rong Xu, Yu Qiu
AIMS: β-amyloid (Aβ) aggregation and deposition play a central role in the pathogenic process of Alzheimer's disease (AD). α-Mangostin (α-M), a polyphenolic xanthone, have been shown to dissociate Aβ oligomers. In this study, we further investigated the effect of α-M on Aβ production and its molecular mechanism. METHODS: The Aβ and soluble amyloid precursor protein α (sAPPα) in culture medium of cortical neurons were measured by ELISA. The activities of α-, β-, and γ-secretases were assayed, and the interaction between α-M and β- or γ-secretases was simulated by molecular docking...
April 21, 2017: CNS Neuroscience & Therapeutics
https://www.readbyqxmd.com/read/28427941/elongation-affinity-activation-barrier-and-stability-of-a%C3%AE-42-oligomers-fibrils-in-physiological-saline
#6
Roberto A Rodriguez, Liao Y Chen, Germán Plascencia-Villa, George Perry
Amyloid-beta (Aβ) peptides, Aβ40 and the more neurotoxic Aβ42, have been the subject of many research efforts for Alzheimer's disease. In two recent independent investigations, the atomistic structure of Aβ42 fibril has been clearly established in the S-shaped conformation consisting of three β-sheets stabilized by salt bridges formed between the Lys28 sidechain and the C-terminus of Ala42. This structure distinctively differs from the long-known structure of Aβ40 in the β-hairpin shaped conformation consisting of two β-sheets...
April 17, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28421539/%C3%AE-synuclein-aggregates-with-%C3%AE-amyloid-or-tau-in-human-red-blood-cells-correlation-with-antioxidant-capability-and-physical-exercise-in-human-healthy-subjects
#7
Simona Daniele, Deborah Pietrobono, Jonathan Fusi, Caterina Iofrida, Lucia Chico, Lucia Petrozzi, Annalisa Lo Gerfo, Filippo Baldacci, Fabio Galetta, Gabriele Siciliano, Ubaldo Bonuccelli, Gino Santoro, Maria Letizia Trincavelli, Ferdinando Franzoni, Claudia Martini
Neurodegenerative disorders (NDs) are characterized by abnormal accumulation/misfolding of specific proteins, primarily α-synuclein (α-syn), β-amyloid1-42 (Aβ), and tau, in both brain and peripheral tissue. In addition to homo-oligomers, the role of α-syn interactions with Aβ or tau has gradually emerged. The altered protein accumulation has been related to both oxidative stress and physical activity; nevertheless, no correlation among the presence of peripheral α-syn hetero-aggregates, antioxidant capacity, and physical exercise has been discovered as of yet...
April 18, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28420731/distinct-modulatory-role-of-rna-in-the-aggregation-of-the-tumor-suppressor-protein-p53-core-domain
#8
Petar Stefanov Kovachev, Debapriya Banerjee, Luciana Pereira Rangel, Jonny Eriksson, Murilo M Pedrote, Mafalda Maria D C Martins-Dinis, Katarina Edwards, Yraima Cordeiro, Jerson L Silva, Suparna Sanyal
Inactivation of the tumor suppressor protein p53 by mutagenesis, chemical modification, protein-protein interaction or aggregation has been associated with different human cancers. Although DNA is the typical substrate of p53, numerous studies have reported p53 interactions with RNA. Here, we have examined the effects of RNA of varied sequence, length and origin on the mechanism of aggregation of the core domain of p53 (p53C) using light scattering, intrinsic fluorescence, transmission electron microscopy, thioflavin-T binding, seeding and immunoblot assays...
April 18, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28420443/tau-phosphorylation-induced-by-severe-closed-head-traumatic-brain-injury-is-linked-to-the-cellular-prion-protein
#9
Richard Rubenstein, Binggong Chang, Natalia Grinkina, Eleanor Drummond, Peter Davies, Meir Ruditzky, Deep Sharma, Kevin Wang, Thomas Wisniewski
Studies in vivo and in vitro have suggested that the mechanism underlying Alzheimer's disease (AD) neuropathogenesis is initiated by an interaction between the cellular prion protein (PrP(C)) and amyloid-β oligomers (Aβo). This PrP(C)-Aβo complex activates Fyn kinase which, in turn, hyperphosphorylates tau (P-Tau) resulting in synaptic dysfunction, neuronal loss and cognitive deficits. AD transgenic mice lacking PrP(C) accumulate Aβ, but show normal survival and no loss of spatial learning and memory suggesting that PrP(C) functions downstream of Aβo production but upstream of intracellular toxicity within neurons...
April 18, 2017: Acta Neuropathologica Communications
https://www.readbyqxmd.com/read/28413720/direct-imaging-of-app-proteolysis-in-living-cells
#10
Niccoló Parenti, Ambra Del Grosso, Claudia Antoni, Marco Cecchini, Renato Corradetti, Francesco S Pavone, Martino Calamai
Alzheimer's disease is a multifactorial disorder caused by the interaction of genetic, epigenetic and environmental factors. The formation of cytotoxic oligomers consisting of Aβ peptide is widely accepted as being one of the main key events triggering the development of Alzheimer's disease. Aβ peptide production results from the specific proteolytic processing of the amyloid precursor protein (APP). Deciphering the factors governing the activity of the secretases responsible for the cleavage of APP is still a critical issue...
2017: PeerJ
https://www.readbyqxmd.com/read/28413635/role-of-amyloid-%C3%AE-protein-receptors-in-mediating-synaptic-plasticity
#11
Yu Li, Zhongqing Sun, Qiaoyu Cao, Meiwan Chen, Huanmin Luo, Xi Lin, Fei Xiao
There are few diseases in modern biomedicine that have garnered as much scientific interest and public concern as Alzheimer's disease (AD). The amyloid hypothesis has become the dominant model of AD pathogenesis; however, the details of the hypothesis are changing over time. Recently, given the increasing recognition, subtle effects of amyloid β protein (Aβ) on synaptic efficacy may be critical to AD progression. Synaptic plasticity is the important neurochemical foundation of learning and memory. Recent studies have identified that soluble Aβ oligomers combine with certain receptors to impair synaptic plasticity in AD, which advanced the amyloid hypothesis...
April 2017: Biomedical Reports
https://www.readbyqxmd.com/read/28412155/ascorbic-acid-inhibits-human-insulin-aggregation-and-protects-against-amyloid-induced-cytotoxicity
#12
Parvez Alam, Ayesha Zainab Beg, Mohammad Khursheed Siddiqi, Sumit Kumar Chaturvedi, Ravi Kant Rajpoot, Mohd Rehan Ajmal, Masihuz Zaman, Ali S Abdelhameed, Rizwan Hasan Khan
Protein aggregation into oligomers and fibrils are associated with many human pathophysiologies. Compounds that modulate protein aggregation and interact with preformed fibrils and convert them to less toxic species, expect to serve as promising drug candidates and aid to the drug development efforts against aggregation diseases. In present study, the kinetics of amyloid fibril formation by human insulin (HI) and the anti-amyloidogenic activity of ascorbic acid (AA) were investigated by employing various spectroscopic, imaging and computational approaches...
May 1, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28412140/chronic-sleep-restriction-promotes-brain-inflammation-and-synapse-loss-and-potentiates-memory-impairment-induced-by-amyloid-%C3%AE-oligomers-in-mice
#13
Grasielle C Kincheski, Isabela S Valentim, Julia R Clarke, Danielle Cozachenco, Morgana T L Castelo-Branco, Angela M Ramos-Lobo, Vivian M B D Rumjanek, José Donato, Fernanda G De Felice, Sergio T Ferreira
It is increasingly recognized that sleep disturbances and Alzheimer's disease (AD) share a bidirectional relationship. AD patients exhibit sleep problems and alterations in the regulation of circadian rhythms; conversely, poor quality of sleep increases the risk of development of AD. The aim of the current study was to determine whether chronic sleep restriction potentiates the brain impact of amyloid-β oligomers (AβOs), toxins that build up in AD brains and are thought to underlie synapse damage and memory impairment...
April 13, 2017: Brain, Behavior, and Immunity
https://www.readbyqxmd.com/read/28400517/aggregation-landscapes-of-huntingtin-exon-1-protein-fragments-and-the-critical-repeat-length-for-the-onset-of-huntington-s-disease
#14
Mingchen Chen, Peter G Wolynes
Huntington's disease (HD) is a neurodegenerative disease caused by an abnormal expansion in the polyglutamine (polyQ) track of the Huntingtin (HTT) protein. The severity of the disease depends on the polyQ repeat length, arising only in patients with proteins having 36 repeats or more. Previous studies have shown that the aggregation of N-terminal fragments (encoded by HTT exon 1) underlies the disease pathology in mouse models and that the HTT exon 1 gene product can self-assemble into amyloid structures. Here, we provide detailed structural mechanisms for aggregation of several protein fragments encoded by HTT exon 1 by using the associative memory, water-mediated, structure and energy model (AWSEM) to construct their free energy landscapes...
April 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28394917/a%C3%AE-levels-in-the-jugular-vein-and-high-molecular-weight-a%C3%AE-oligomer-levels-in-csf-can-be-used-as-biomarkers-to-indicate-the-anti-amyloid-effect-of-ivig-for-alzheimer-s-disease
#15
Takashi Kasai, Masaki Kondo, Ryotaro Ishii, Akihiro Tanaka, Suzuka Ataka, Hiroyuki Shimada, Takami Tomiyama, Hiroshi Mori, Mark Taylor, David Allsop, Masanori Nakagawa, Toshiki Mizuno, Takahiko Tokuda
Intravenous immunoglobulin (IVIg) has been a candidate as a potential anti-amyloid immunotherapy for Alzheimer disease (AD) because it contains anti-amyloid β (Aβ) antibodies. Although several studies with IVIg in AD have been published, changing levels of Aβ efflux from the brain, or disaggregation of Aβ species induced by immunotherapy, have not been properly investigated. Here, we carried out an open label study of therapy with IVIg in five patients with AD. We collected plasma from a peripheral vein (peripheral-plasma) and from the internal jugular vein (jugular-plasma) to estimate directly the efflux of soluble Aβ from the brain...
2017: PloS One
https://www.readbyqxmd.com/read/28394449/efficient-gene-transfection-through-inhibition-of-%C3%AE-sheet-amyloid-fiber-formation-of-a-short-amphiphilic-peptide-by-gold-nanoparticles
#16
Poulami Jana, Krishnananda Samanta, Sandra Bäcker, Elio Zellermann, Shirley Knauer, Carsten Schmuck
The effect of citrate-stabilized gold nanoparticles (AuNPs) on the secondary structure of an artificial β-sheet-forming cationic peptide has been studied. The AuNPs inhibited β-sheet formation and led to fragmented fibrils and spherical oligomers with assembled AuNPs on their surface. Besides this structural change, the functional properties of the peptide are also different. Whereas the peptide was unable to act as a vector for gene delivery, formation of a complex with AuNPs allowed successful gene delivery into cells...
April 10, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28392295/oleocanthal-ameliorates-amyloid-%C3%AE-oligomers-toxicity-on-astrocytes-and-neuronal-cells-in-vitro-studies
#17
Yazan S Batarseh, Loqman A Mohamed, Sweilem B Al Rihani, Youssef M Mousa, Abu Bakar Siddique, Khalid A El Sayed, Amal Kaddoumi
Extra-virgin olive oil (EVOO) has several health promoting effects. Evidence have shown that EVOO attenuates the pathology of amyloid-β (Aβ) and improves cognitive function in experimental animal models, suggesting it's potential to protect and reduce the risk of developing Alzheimer's disease (AD). Available studies have linked this beneficial effect to oleocanthal, one of the active components in EVOO. The effect of oleocanthal against AD pathology has been linked to its ability to attenuate Aβ and tau aggregation in vitro, and enhance Aβ clearance from the brains of wild-type and AD transgenic mice in vivo...
April 7, 2017: Neuroscience
https://www.readbyqxmd.com/read/28391388/transglutaminases-derived-from-astrocytes-accelerate-amyloid-%C3%AE-aggregation
#18
Kenji Kawabe, Katsura Takano, Mitsuaki Moriyama, Yoichi Nakamura
Activation of astrocytes has been observed in neurodegenerative diseases including Alzheimer's disease (AD). Transglutaminase (TG) is a crosslinking enzyme and contributes to cell adhesion, cytoskeleton construct, extracellular matrix formation, and so on. One of the isozymes, tissue-type TG (TG2) is reported to be activated in AD. Moreover, amyloid β1-42 (Aβ), which is aggregated and the aggregation is detected as characteristic pathology in AD brain, is known to be a substrate of TG2. However, contribution and derivation of TGs in brain for Aβ aggregation remain to be clarified...
April 9, 2017: Neurochemical Research
https://www.readbyqxmd.com/read/28390893/targeting-glutamatergic-and-cellular-prion-protein-mechanisms-of-amyloid-%C3%AE-mediated-persistent-synaptic-plasticity-disruption-longitudinal-studies
#19
Dainan Zhang, Yingjie Qi, Igor Klyubin, Tomas Ondrejcak, Claire J Sarell, A Claudio Cuello, John Collinge, Michael J Rowan
Alzheimer's disease amyloid-β (Aβ) oligomers are synaptotoxic, inappropriately increasing extracellular glutamate concentration and glutamate receptor activation to thereby rapidly disrupt synaptic plasticity. Thus, acutely promoting brain glutamate homeostasis with a blood-based scavenging system, glutamate-oxaloacetate transaminase (GOT), and blocking metabotropic glutamate 5 (mGlu5) receptor or its co-receptor cellular prion protein (PrP), prevent the acute inhibition of long-term potentiation (LTP) by exogenous Aβ...
April 5, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28390823/the-expression-and-activity-of-kv3-4-channel-subunits-are-precociously-upregulated-in-astrocytes-exposed-to-a%C3%AE-oligomers-and-in-astrocytes-of-alzheimer-s-disease-tg2576-mice
#20
Francesca Boscia, Anna Pannaccione, Roselia Ciccone, Antonella Casamassa, Cristina Franco, Ilaria Piccialli, Valeria de Rosa, Antonio Vinciguerra, Gianfranco Di Renzo, Lucio Annunziato
Astrocyte dysfunction emerges early in Alzheimer's disease (AD) and may contribute to its pathology and progression. Recently, the voltage gated potassium channel KV3.4 subunit, which underlies the fast-inactivating K(+) currents, has been recognized to be relevant for AD pathogenesis and is emerging as a new target candidate for AD. In the present study, we investigated both in in vitro and in vivo models of AD the expression and functional activity of KV3.4 potassium channel subunits in astrocytes. In primary astrocytes our biochemical, immunohistochemical, and electrophysiological studies demonstrated a time-dependent upregulation of KV3...
June 2017: Neurobiology of Aging
keyword
keyword
105485
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"