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amyloid oligomer

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https://www.readbyqxmd.com/read/28343095/ion-mobility-mass-spectrometry-and-orthogonal-gas-phase-techniques-to-study-amyloid-formation-and-inhibition
#1
REVIEW
Waldemar Hoffmann, Gert von Helden, Kevin Pagel
Amyloidogenic peptide oligomers are responsible for a variety of neurodegenerative disorders such as Alzheimer's and Parkinson's disease. Due to their dynamic, polydisperse, and polymorphic nature, these oligomers are very challenging to characterize using traditional condensed-phase methods. In the last decade, ion mobility-mass spectrometry (IM-MS) and related gas-phase techniques have emerged as a powerful alternative to disentangle the structure and assembly characteristics of amyloid forming systems. This review highlights recent advances in which IM-MS was used to characterize amyloid oligomers and their underlying assembly pathway...
March 23, 2017: Current Opinion in Structural Biology
https://www.readbyqxmd.com/read/28342736/amyloidogenicity-at-a-distance-how-distal-protein-regions-modulate-aggregation-in-disease
#2
REVIEW
Christina M Lucato, Christopher C Lupton, Michelle L Halls, Andrew M Ellisdon
The misfolding of proteins to form amyloid is a key pathological feature of several progressive, and currently incurable, diseases. A mechanistic understanding of the pathway from soluble, native protein to insoluble amyloid is crucial for therapeutic design and recent efforts have helped to elucidate the key molecular events that trigger protein misfolding. Generally, either global or local structural perturbations occur early in amyloidogenesis to expose aggregation-prone regions of the protein that can then self-associate to form toxic oligomers...
March 22, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28340507/understanding-the-contribution-of-disulphide-bridges-to-the-folding-and-misfolding-of-an-anti-a%C3%AE-scfv
#3
Laia Montoliu-Gaya, Jose C Martínez, Sandra Villegas
ScFv-h3D6 is a single chain variable fragment that precludes Aβ peptide-induced cytotoxicity by withdrawing Aβ oligomers from the amyloid pathway to the worm-like pathway. Production of scFv molecules is not a straightforward procedure because of the occurrence of disulphide scrambled conformations generated in the refolding process. Here, we separately removed the disulphide bond of each domain and solved the scrambling problem; and then, we intended to compensate the loss of thermodynamic stability by adding three C-terminal elongation mutations previously described to stabilize the native fold of scFv-h3D6...
March 24, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28337747/structure-dependent-effects-of-amyloid-%C3%AE-on-long-term-memory-in-lymnaea-stagnalis
#4
Lenzie Ford, Michael Crossley, Devkee M Vadukul, György Kemenes, Louise C Serpell
Amyloid-β (Aβ) peptides are implicated in the causation of memory loss, neuronal impairment, and neurodegeneration in Alzheimer's disease. Our recent work revealed that Aβ 1-42 and Aβ 25-35 inhibit long-term memory (LTM) recall in Lymnaea stagnalis (pond snail) in the absence of cell death. Here, we report the characterization of the active species prepared under different conditions, describe which Aβ species is present in brain tissue during the behavioral recall time point and relate the sequence and structure of the oligomeric species to the resulting neuronal properties and effect on LTM...
March 24, 2017: FEBS Letters
https://www.readbyqxmd.com/read/28336494/minocycline-reduces-inflammatory-parameters-in-the-brain-structures-and-serum-and-reverses-memory-impairment-caused-by-the-administration-of-amyloid-%C3%AE-1-42-in-mice
#5
Michelle Lima Garcez, Francielle Mina, Tatiani Bellettini-Santos, Franciellen Gonçalves Carneiro, Aline Pereira da Luz, Gustavo Luis Schiavo, Matheus Scopel Andrighetti, Maylton Grégori Scheid, Renan Pereira Bolfe, Josiane Budni
Alzheimer's disease (AD) is a neurodegenerative disorder and the most common type of age-related dementia. Cognitive decline, beta-amyloid (Aβ) accumulation, neurofibrillary tangles, and neuroinflammation are the main pathophysiological characteristics of AD. Minocycline is a tetracycline derivative with anti-inflammatory properties that has a neuroprotective effect. The aim of this study was to evaluate the effect of minocycline on memory, neurotrophins and neuroinflammation in an animal model of AD induced by the administration of Aβ (1-42) oligomer...
March 20, 2017: Progress in Neuro-psychopharmacology & Biological Psychiatry
https://www.readbyqxmd.com/read/28332150/dynamic-nature-of-presenilin1-%C3%AE-secretase-implication-for-alzheimer-s-disease-pathogenesis
#6
REVIEW
Katarzyna Marta Zoltowska, Oksana Berezovska
Presenilin 1 (PS1) is a catalytic component of the γ-secretase complex, responsible for the intramembraneous cleavage of more than 90 type I transmembrane proteins, including Alzheimer's disease (AD)-related amyloid precursor protein (APP). The γ-secretase-mediated cleavage of the APP C-terminal membrane stub leads to the production of various amyloid β (Aβ) species. The assembly of Aβ into neurotoxic oligomers, which causes synaptic dysfunction and neurodegeneration, is influenced by the relative ratio of the longer (Aβ42/43) to shorter Aβ (Aβ40) peptides...
March 22, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28330719/nicotinamide-mononucleotide-inhibits-jnk-activation-to-reverse-alzheimer-disease
#7
Zhiwen Yao, Wenhao Yang, Zhiqiang Gao, Peng Jia
Amyloid-β (Aβ) oligomers have been accepted as major neurotoxic agents in the therapy of Alzheimer's disease (AD). It has been shown that the activity of nicotinamide adenine dinucleotide (NAD+) is related with the decline of Aβ toxicity in AD. Nicotinamide mononucleotide (NMN), the important precursor of NAD+, is produced during the reaction of nicotinamide phosphoribosyl transferase (Nampt). This study aimed to figure out the potential therapeutic effects of NMN and its underlying mechanisms in APPswe/PS1dE9 (AD-Tg) mice...
March 18, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28327181/soluble-oligomeric-amyloid-%C3%AE-induces-calcium-dyshomeostasis-that-precedes-synapse-loss-in-the-living-mouse-brain
#8
Michal Arbel-Ornath, Eloise Hudry, Josiah R Boivin, Tadafumi Hashimoto, Shuko Takeda, Kishore V Kuchibhotla, Steven Hou, Carli R Lattarulo, Arianna M Belcher, Naomi Shakerdge, Pariss B Trujillo, Alona Muzikansky, Rebecca A Betensky, Bradley T Hyman, Brian J Bacskai
BACKGROUND: Amyloid-β oligomers (oAβ) are thought to mediate neurotoxicity in Alzheimer's disease (AD), and previous studies in AD transgenic mice suggest that calcium dysregulation may contribute to these pathological effects. Even though AD mouse models remain a valuable resource to investigate amyloid neurotoxicity, the concomitant presence of soluble Aβ species, fibrillar Aβ, and fragments of amyloid precursor protein (APP) complicate the interpretation of the phenotypes. METHOD: To explore the specific contribution of soluble oligomeric Aβ (oAβ) to calcium dyshomeostasis and synaptic morphological changes, we acutely exposed the healthy mouse brain, at 3 to 6 months of age, to naturally occurring soluble oligomers and investigated their effect on calcium levels using in vivo multiphoton imaging...
March 21, 2017: Molecular Neurodegeneration
https://www.readbyqxmd.com/read/28323849/bis-sulfosuccinimidyl-suberate-bs3-crosslinking-analysis-of-the-behavior-of-amyloid-%C3%AE-peptide-in-solution-and-in-phospholipid-membranes
#9
Jing-Ming Shi, Jie Pei, En-Qi Liu, Lin Zhang
The structure and state of amyloid-β peptide (Aβ) oligomers often need to be checked by reliable experimental methods. Electrophoresis is a commonly applied measurement method. However, due to the presence of detergents, oligomers are easily broken during electrophoresis, which makes it very hard to accurately assess Aβ aggregate states. In the current study, bis(sulfosuccinimidyl) suberate (BS3) was used to cross-link Aβ1-42 oligomers prior to electrophoresis. When compared to a previously reported Aβ cross-linking agent, glutaraldehyde, it was quite apparent that BS3 is more suitable for detecting intra-membrane Aβ oligomers and extra-membrane Aβ oligomers states...
2017: PloS One
https://www.readbyqxmd.com/read/28318364/defective-retrograde-transport-impairs-autophagic-clearance-in-alzheimer-disease-neurons
#10
Prasad Tammineni, Qian Cai
Macroautophagy/autophagy plays a key role in cellular quality control by eliminating protein aggregates and damaged organelles, which is essential for the maintenance of neuronal homeostasis. Defective autophagy has been implicated in the pathogenesis of Alzheimer disease (AD). In AD brains, autophagic vacuoles (AVs) accumulate massively within dystrophic neurites. This raises a fundamental question as to whether impaired autophagic clearance contributes to AD-associated autophagic stress. We recently revealed that AD neurons display defective retrograde transport and accumulation of amphisomes predominantly in axons and presynaptic terminals...
February 28, 2017: Autophagy
https://www.readbyqxmd.com/read/28317984/stabilizing-the-monomeric-amyloid-%C3%AE-peptide-by-tyrocidine-a-prevents-and-reverses-amyloidogenesis-without-the-accumulation-of-oligomers
#11
Gesi Wen, Wenjing Qin, Daoyuan Chen, Youqiao Wang, Xin Yue, Ziyi Liu, Yingnan Cao, Jun Du, Binhua Zhou, Xianzhang Bu
Amyloid-β (Aβ) oligomers are causative agents triggering AD pathogenesis, but their elimination remains challenging. We herein reported a natural cyclopeptide tyrocidine A prevents and reverses amyloidogenesis without Aβ oligomer accumulation by stabilizing the monomeric, but not the oligomeric state of Aβ peptides.
March 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28302722/amyloid-%C3%AE-oligomers-transiently-inhibit-amp-activated-kinase-and-cause-metabolic-defects-in-hippocampal-neurons
#12
Gisele S Seixas da Silva, Helen M Melo, Mychael V Lourenco, Natalia de M Lyra E Silva, Marcelo B de Carvalho, Soniza Alves-Leon, Jorge M de Souza, William L Klein, Wagner S da-Silva, Sergio T Ferreira, Fernanda G De Felice
AMP-activated kinase (AMPK) is a key player in energy sensing and metabolic reprogramming under cellular energy restriction. Several studies have linked impaired AMPK function to peripheral metabolic diseases such as diabetes. However, the impact of neurological disorders, such as Alzheimer disease (AD), on AMPK function and downstream effects of altered AMPK activity on neuronal metabolism have been investigated only recently. Here, we report the impact of A β oligomers (AβOs), synaptotoxins that accumulate in AD brains, on neuronal AMPK activity...
March 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28301805/the-protective-role-of-plant-biophenols-in-mechanisms-of-alzheimer-s-disease
#13
REVIEW
Syed H Omar, Christopher J Scott, Adam S Hamlin, Hassan K Obied
Self-assembly of amyloid beta peptide (Aβ) into the neurotoxic oligomers followed by fibrillar aggregates is a defining characteristic of Alzheimer's disease (AD). Several lines of proposed hypotheses have suggested the mechanism of AD pathology, though the exact pathophysiological mechanism is not yet elucidated. The poor understanding of AD and multitude of adverse responses reported from the current synthetic drugs are the leading cause of failure in the drug development to treat or halt the progression of AD and mandate the search for safer and more efficient alternatives...
March 3, 2017: Journal of Nutritional Biochemistry
https://www.readbyqxmd.com/read/28295502/assessment-of-renal-response-with-urinary-exosomes-in-patients-with-al-amyloidosis-a-proof-of-concept
#14
Marina Ramirez-Alvarado, David R Barnidge, David L Murray, Angela Dispenzieri, Marta Marin-Argany, Christopher J Dick, Shawna A Cooper, Samih H Nasr, Christopher J Ward, Surendra Dasari, Víctor H Jiménez-Zepeda, Nelson Leung
Immunoglobulin light chain (AL) amyloidosis is a fatal complication of B-cell proliferation secondary to deposition of amyloid fibrils in various organs. Urinary exosomes (UEX) are the smallest of the microvesicles excreted in the urine. Previously, we found UEX of patients with AL amyloidosis contained immunoglobulin light chain (LC) oligomers that patients with multiple myeloma did not have. To further explore the role of the LC oligomers, UEX was isolated from an AL amyloidosis patient with progressive renal disease despite achieving a complete response...
March 10, 2017: American Journal of Hematology
https://www.readbyqxmd.com/read/28294556/unmodified-and-pyroglutamylated-amyloid-%C3%AE-peptides-form-hypertoxic-hetero-oligomers-of-unique-secondary-structure
#15
Greg Goldblatt, Lucia Cilenti, Jason O Matos, Briana Lee, Nicholas Ciaffone, Qing X Wang, Laurene Tetard, Ken Teter, Suren A Tatulian
Amyloid β (Aβ) peptide plays a major role in Alzheimer's disease (AD) and occurs in multiple forms, including pyroglutamylated Aβ (AβpE). Identification and characterization of the most cytotoxic Aβ species is necessary for advancement in AD diagnostics and therapeutics. While in brain tissue multiple Aβ species act in combination, structure/toxicity studies and immunotherapy trials have been focused on individual forms of Aβ. As a result, the molecular composition and the structural features of "toxic Aβ oligomers" have remained unresolved...
March 13, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28290684/polymer-peptide-conjugates-disassemble-amyloid-%C3%AE-fibrils-in-a-molecular-weight-dependent-manner
#16
Yang Song, Edwin G Moore, Yanshu Guo, Jeffrey S Moore
Amyloid aggregation and deposition are associated with many intractable human diseases. Although the inhibition of amyloid protein aggregation has been well-studied, the disaggregation and dissolution of existing amyloid fibrils is less known. Taking a fibrillar assembly of amyloid β (Aβ) peptide as the model system, here we report multivalent polymer-peptide conjugates (mPPCs) that disassemble preformed Aβ fibrils into dispersible sub-100 nm structures. Atomic force microscopy and dynamic light scattering studies show that the disassembly rate of preformed Aβ fibrils is controlled by the molecular weight of mPPCs...
March 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28290668/surface-assay-for-specific-detection-of-soluble-amyloid-oligomers-utilizing-pronucleon-peptides-instead-of-antibodies
#17
Evgenia G Matveeva, Jonathan R Moll, Mariam M Khan, Richard B Thompson, Richard O Cliff
Immunoassays such as enzyme-linked immunosorbent assays (ELISAs) are widely used for diagnostics; however, antibodies as detection reagents may be insufficiently selective and have other shortcomings. We present a novel non-antibody-based detection method based on binding target molecules to peptides (used as recognition molecules): a surface assay for A-β oligomers employing a peptide comprising amino acid residues of the human β-amyloid protein (Pronucleon peptide) as the capture agent. For the sake of convenience, we term this the "Pronucleon peptide-linked immunosorbent assay", or PLISA...
March 21, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28290665/kaplan-meier-meets-chemical-kinetics-intrinsic-rate-of-sod1-amyloidogenesis-decreased-by-subset-of-als-mutations-and-cannot-fully-explain-age-of-disease-onset
#18
Alireza Abdolvahabi, Yunhua Shi, Sanaz Rasouli, Corbin M Croom, Amir Aliyan, Angel A Marti, Bryan F Shaw
Over 150 mutations in SOD1 (superoxide dismutase-1) cause amyotrophic lateral sclerosis (ALS), presumably by accelerating SOD1 amyloidogenesis. Like many nucleation processes, SOD1 fibrillization is stochastic (in vitro), which inhibits determination of aggregation rates (and obscures whether rates correlate with patient phenotypes). Here, we diverged from classical chemical kinetics and used Kaplan-Meier estimators to quantify the probability of apo-SOD1 fibrillization (in vitro) from ~ 10(3) replicate amyloid assays of wild-type (WT) SOD1 and nine ALS variants...
March 14, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28283575/interaction-of-a%C3%AE-oligomers-with-neurexin-2%C3%AE-and-neuroligin-1-mediates-synapse-damage-and-memory-loss-in-mice
#19
Jordano Brito-Moreira, Mychael V Lourenco, Mauricio M Oliveira, Juliana F S Vital, Felipe C Ribeiro, José Henrique Ledo, Luan P Diniz, Margaret H Magdesian, Helen M Melo, Fernanda Barros-Aragão, Jorge M de Souza, Soniza V Alves-Leon, Flavia C A Gomes, Julia R Clarke, Cláudia P Figueiredo, Fernanda G De Felice, Sergio T Ferreira
Brain accumulation of the amyloid-β protein (Aβ) and synapse loss are neuropathological hallmarks of Alzheimer disease (AD). Aβ oligomers (AβOs) are synaptotoxins that build up in the brains of patients and are thought to contribute to memory impairment in AD. Thus, identification of novel synaptic components that are targeted by AβOs will likely contribute to the elucidation of disease-relevant mechanisms. Trans-synaptic interactions between neurexins (Nrxs) and neuroligins (NLs) are essential for synapse structure, stability and function, and reduced NL levels have been recently associated with AD...
March 10, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28283460/anti-parkinsonian-l-dopa-can-also-act-as-anti-systemic-amyloidosis-a-mechanistic-exploration
#20
Saima Nusrat, Nida Zaidi, Mohammad Khursheed Siddiqi, Masihuz Zaman, Ibrar Ahmed Siddique, Mohammad Rehan Ajmal, Ali Saber Abdelhameed, Rizwan Hasan Khan
In spite of the fact that amyloid related neurodegenerative illnesses and non-neuropathic systemic amyloidosis have allured the research endeavors, as no cure has been announced yet apart from symptomatic treatment. Therapeutic agents which can reduce or disaggregate those toxic oligomers and fibrillar species have been studied with more compounds are on their way. The current research work describes comprehensive biophysical, computational and microscopic studies which reveal that L-3, 4-dihydroxyphenylalanine (L-Dopa) have indisputable efficacy to hinder the heat induced amyloid fibrillation of the human lysozyme (HL) and also preserve the fibril disaggregating potential...
March 7, 2017: International Journal of Biological Macromolecules
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