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Asad Jan, Brandon Jansonius, Alberto Delaidelli, Syam Prakash Somasekharan, Forum Bhanshali, Milène Vandal, Gian Luca Negri, Don Moerman, Ian MacKenzie, Frédéric Calon, Michael R Hayden, Stefan Taubert, Poul H Sorensen
Soluble oligomers of amyloid-β (Aβ) impair synaptic plasticity, perturb neuronal energy homeostasis, and are implicated in Alzheimer's disease (AD) pathogenesis. Therefore, significant efforts in AD drug discovery research aim to prevent the formation of Aβ oligomers or block their neurotoxicity. The eukaryotic elongation factor-2 kinase (eEF2K) plays a critical role in synaptic plasticity, and couples neurotransmission to local dendritic mRNA translation. Recent evidence indicates that Aβ oligomers activate neuronal eEF2K, suggesting a potential link to Aβ induced synaptic dysfunction...
October 17, 2016: Acta Neuropathologica
Kazuhiro Yokota, Dai Kishida, Hidekazu Kayano, Masahide Yazaki, Yuki Shimada, Yuji Akiyama, Toshihide Mimura
We report the case of a Japanese woman with amyloid light chain (AL) amyloidoma in the abdominal aortic retroperitoneum and mesentery. Irregular soft tissue mass lesions with calcification in the abdominal aortic retroperitoneum and mesentery were initially detected by computed tomography at another hospital. The lesions gradually compressed the duodenum, causing symptoms of bowel obstruction. The patient was clinically diagnosed with retroperitoneal fibrosis, and prednisolone was administered at a dose of 40 mg/day...
2016: Case Reports in Rheumatology
Zaria Ali, Bertie Fernando
Amyloidosis of the eyelid is uncommon and is typically associated with systemic associations. In contrast, amyloidosis of the conjunctiva is often localised with no other associations. We present a rare case of a 92-year-old gentleman with both cutaneous lid lesions and conjunctival amyloid with no systemic involvement. Biopsy demonstrated the hallmarks of amyloid and treatment has remained conservative. He remains at the department to be monitored for secondary glaucoma.
2016: Case Reports in Ophthalmological Medicine
D A Bangasser, H Dong, J Carroll, Z Plona, H Ding, L Rodriguez, C McKennan, J G Csernansky, S H Seeholzer, R J Valentino
Several neuropsychiatric and neurodegenerative disorders share stress as a risk factor and are more prevalent in women than in men. Corticotropin-releasing factor (CRF) orchestrates the stress response, and excessive CRF is thought to contribute to the pathophysiology of these diseases. We previously found that the CRF1 receptor (CRF1) is sex biased whereby coupling to its GTP-binding protein, Gs, is greater in females, whereas β-arrestin-2 coupling is greater in males. This study used a phosphoproteomic approach in CRF-overexpressing (CRF-OE) mice to test the proof of principle that when CRF is in excess, sex-biased CRF1 coupling translates into divergent cell signaling that is expressed as different brain phosphoprotein profiles...
October 18, 2016: Molecular Psychiatry
Claudia Balducci, Angelisa Frasca, Margherita Zotti, Pietro La Vitola, Emanuela Mhillaj, Emanuele Grigoli, Martina Iacobellis, Federica Grandi, Massimo Messa, Laura Colombo, Monica Molteni, Luigia Trabace, Carlo Rossetti, Mario Salmona, Gianluigi Forloni
[Background] Amyloid-β oligomers (AβO) are species mainly involved in the synaptic and cognitive dysfunction in Alzheimer's disease. Although their action has been described mainly at neuronal level, it is now clear that glial cells govern synaptic activity in their resting state, contributing to new learning and memory establishment. In contrast, when activated, they may lead to synaptic and cognitive dysfunction. Using a reliable acute AβO-mediated mouse model of AD, we explored whether the memory alteration AβOs induce relies on the activation of glial cells, and if Toll-like receptor 4 (TLR4), pivotal in the initiation of an immune response, is involved...
October 14, 2016: Brain, Behavior, and Immunity
George Taylor-Walker, Savannah A Lynn, Eloise Keeling, Rosie Munday, David A Johnston, Anton Page, Jennifer A Scott, Srini Goverdhan, Andrew J Lotery, J Arjuna Ratnayaka
Age-related Macular Degeneration (AMD) is a common, irreversible blinding condition that leads to the loss of central vision. AMD has a complex aetiology with both genetic as well as environmental risks factors, and share many similarities with Alzheimer's disease. Recent findings have contributed significantly to unravelling its genetic architecture that is yet to be matched by molecular insights. Studies are made more challenging by observations that aged and AMD retinas accumulate the highly pathogenic Alzheimer's-related Amyloid beta (Aβ) group of peptides, for which there appears to be no clear genetic basis...
October 14, 2016: Experimental Eye Research
Koning Shen, Barbara Calamini, Jonathan A Fauerbach, Boxue Ma, Sarah H Shahmoradian, Ivana L Serrano Lachapel, Wah Chiu, Donald C Lo, Judith Frydman
Many neurodegenerative diseases are linked to amyloid aggregation. In Huntington's disease (HD), neurotoxicity correlates with increased aggregation propensity of a polyglutamine (polyQ) expansion in exon 1 of mutant huntingtin protein (mHtt). Here we establish how the domains flanking the polyQ tract shape the mHtt conformational landscape in vitro and in neurons. In vitro, the flanking domains have opposing effects on the conformation and stabilities of oligomers and amyloid fibrils. The N-terminal N17 promotes amyloid fibril formation, while the C-terminal Proline Rich Domain destabilizes fibrils and enhances oligomer formation...
October 18, 2016: ELife
Tiernan Thomas O'Malley, William M Wittbold, Sara Linse, Dominic M Walsh
Extracts of Alzheimer's disease (AD) brain that contain what appear to be SDS-stable amyloid β-protein (Aβ) dimers potently block LTP and impair memory consolidation. Brain-derived dimers can be physically separated from Aβ monomer, consist primarily of Aβ42 and resist denaturation by powerful chaotropic agents. In nature, covalently cross-linked Aβ dimers could be generated in only one of two different ways - either by the formation of a dityrosine (DiY) or an isopeptide ε-(γ-glutamyl)-lysine (Q-K) bond...
October 17, 2016: Biochemistry
Hu Shi, Baotao Kang, Jin Yong Lee
Histidine state (deprotonated, neutral, and protonated) is considered an important factor influencing the structural properties and aggregation mechanisms in amyloid β-peptides which are associated with the pathogenesis of Alzheimer's disease. Understanding the structural properties and aggregation mechanisms is a great challenge because two forms (the Nε-H or Nδ-H tautomer) can exist in the free neutral state of histidine. Here, replica exchange molecular dynamics simulation was performed to elucidate the changes of structure and mechanism of aggregation influenced by tautomeric behaviors of histidine in Aβ (1-40)...
October 17, 2016: Journal of Physical Chemistry. B
Natalia A Stefanova, Natalia A Muraleva, Kseniya Yi Maksimova, Ekaterina A Rudnitskaya, Elena Kiseleva, Darya V Telegina, Nataliya G Kolosova
Mitochondrial aberrations are observed in human Alzheimer's disease (AD) and in medical conditions that increase the risk of this disorder, suggesting that mitochondrial dysfunction may contribute to pathophysiology of AD. Here, using OXYS rats that simulate key characteristics of sporadic AD, we set out to determine the role of mitochondria in the pathophysiology of this disorder. OXYS rats were treated with a mitochondria-targeted antioxidant SkQ1 from age 12 to 18 months, that is, during active progression of AD-like pathology in these animals...
October 6, 2016: Aging
Juliane Schelle, Lisa Häsler, Jens C Göpfert, Thomas O Joos, Hugo Vanderstichele, Erik Stoops, Ulf Neumann, Derya R Shimshek, Matthias Staufenbiel, Mathias Jucker, Stephan A Kaeser
INTRODUCTION: The inhibition of the beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1) is a main therapeutic approach for the treatment of Alzheimer's disease (AD). We previously reported an age-related increase of tau protein in the cerebrospinal fluid (CSF) of Aβ precursor protein (APP) transgenic mice. METHODS: APP transgenic mice were treated with a potent BACE1 inhibitor. CSF tau and CSF Aβ levels were assessed. A novel high-sensitivity tau sandwich immunoassay was developed...
October 14, 2016: Alzheimer's & Dementia: the Journal of the Alzheimer's Association
Yilong Tu, Shuai Ma, Fufeng Liu, Yan Sun, Xiaoyan Dong
Accumulation and aggregation of amyloid β-protein (Aβ) play an important role in the pathogenesis of Alzheimer's disease. There has been increased interest in finding new anti-amyloidogenic compounds to inhibit Aβ aggregation. Herein, thioflavin T fluorescent assay and transmission electron microscopy results showed that hematoxylin, a natural organic molecule extracted from caesalpinia sappan, was a powerful inhibitor of Aβ42 fibrillogenesis. Circular dichroism studies revealed hematoxylin reduced the β-sheet content of Aβ42 and made it assemble into antiparallel arrangement, which induced Aβ42 to form off-pathway aggregates...
October 17, 2016: Journal of Physical Chemistry. B
Elizabeth M S Schmidt, Mads Kjelgaard-Hansen, Funmilola Thomas, Asta Tvarijonaviciute, José J Cerón, P David Eckersall
BACKGROUND: Dioctophyme renale is a nematode parasite of dogs, usually found in the right kidney, causing severe damage to the renal parenchyma. OBJECTIVES: The objective was to evaluate the acute phase response in dogs naturally infected with this Giant Kidney Worm and the possible effects of nephrectomy on circulating concentrations of select acute phase proteins (APP) such as serum amyloid A (SAA), C-reactive protein (CRP), and haptoglobin (HP). METHODS: Nephrectomy was performed in infected dogs and the worms were collected for identification...
October 17, 2016: Veterinary Clinical Pathology
Robert W Newberry, Ronald T Raines
Current limitations in de novo protein structure prediction and design suggest an incomplete understanding of the interactions that govern protein folding. Here we demonstrate that previously unappreciated hydrogen bonds occur within proteins between the amide proton and carbonyl oxygen of the same residue. Quantum calculations, infrared spectroscopy, and nuclear magnetic resonance spectroscopy show that these interactions share hallmark features of canonical hydrogen bonds. Biophysical analyses demonstrate that selective attenuation or enhancement of these C5 hydrogen bonds affects the stability of synthetic β-sheets...
October 17, 2016: Nature Chemical Biology
Rosemary J Jackson, Nikita Rudinskiy, Abigail G Herrmann, Shaun Croft, JeeSoo Monica Kim, Veselina Petrova, Juan Jose Ramos-Rodriguez, Rose Pitstick, Susanne Wegmann, Monica Garcia-Alloza, George A Carlson, Bradley T Hyman, Tara L Spires-Jones
Alzheimer's disease is characterized by the presence of aggregates of amyloid beta (Aβ) in senile plaques and tau in neurofibrillary tangles, as well as marked neuron and synapse loss. Of these pathological changes, synapse loss correlates most strongly with cognitive decline. Synapse loss occurs prominently around plaques due to accumulations of oligomeric Aβ. Recent evidence suggests that tau may also play a role in synapse loss but the interactions of Aβ and tau in synapse loss remain to be determined...
October 17, 2016: European Journal of Neuroscience
J M G van Bergen, X Li, J Hua, S J Schreiner, S C Steininger, F C Quevenco, M Wyss, A F Gietl, V Treyer, S E Leh, F Buck, R M Nitsch, K P Pruessmann, P C M van Zijl, C Hock, P G Unschuld
Quantitative Susceptibility Mapping (QSM) MRI at 7 Tesla and 11-Carbon Pittsburgh-Compound-B PET were used for investigating the relationship between brain iron and Amyloid beta (Aβ) plaque-load in a context of increased risk for Alzheimer's disease (AD), as reflected by the Apolipoprotein E ε4 (APOE-e4) allele and mild cognitive impairment (MCI) in elderly subjects. Carriers of APOE-e4 with normal cognition had higher cortical Aβ-plaque-load than non-carriers. In MCI an association between APOE-e4 and higher Aβ-plaque-load was observable both for cortical and subcortical brain-regions...
October 17, 2016: Scientific Reports
Qian Zhao, Xueqi Chen, Yun Zhou
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, causing changes in memory, thinking, and other dysfunction of brain functions. More and more people are suffering from the disease. Early neuroimaging techniques of AD are needed to develop. This review provides a preliminary summary of the various neuroimaging techniques that have been explored for in vivo imaging of AD. Recent advances in magnetic resonance (MR) techniques, such as functional MR imaging (fMRI) and diffusion MRI, give opportunities to display not only anatomy and atrophy of the medial temporal lobe, but also at microstructural alterations or perfusion disturbance within the AD lesions...
March 2016: Brain Informatics
Hua-Jin Zeng, Min Miao, Zhe Liu, Ran Yang, Ling-Bo Qu
In this study, the fibrillation of hen egg-white lysozyme (HEWL) in the absence and presence of different amount of nitrogen-doped graphene quantum dots (N-GQDs) was studied by Thioflavin T (ThT) spectroscopy, Congo red (CR) binding assays, 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence assay, circular dichroism (CD) and transmission electron microscopy (TEM). The experimental results indicated that not only the fibrillation of HEWL at high temperature (65°C) and low pH (pH=2.0) could be inhibited effectively by N-GQDs, but the inhibition of HEWL by N-GQDs followed a dose-dependent manner...
October 13, 2016: International Journal of Biological Macromolecules
Romana Parveen, Tooba Naz Shamsi, Sadaf Fatima
This review helps to understand protein misfolding events, which results in protein aggregation, and hence to related neurodegenerative diseases. Many chaperones and folding factors are found inside the cell system for the proper folding of protein. If protein gets misfolded, it may accumulate in cells and can lead to several fatal diseases. In some cases, misfolded proteins aggregated in form of loop-sheet polymer and amyloid fibril when they escape the degradation process and leads to neurodegenerative disorders...
October 13, 2016: International Journal of Biological Macromolecules
Yanping Yang, Xuedan Wang, Hui Yang, Hualong Fu, Jinming Zhang, Xiaojun Zhang, Jiapei Dai, Zhiyong Zhang, Chunping Lin, Yuzhi Guo, Mengchao Cui
This study describes an effective strategy to improve pharmacokinetics of Aβ imaging agents, offering a novel class of (R)- and (S)-18F-labeled 2-arylbenzoheterocyclic derivatives which bear an additional chiral hydroxyl group on the side chain. These ligands displayed binding abilities toward Aβ aggregates with Ki values varying from 3.2 to 195.6 nM. Chirality-related discrepancy was observed in biodistribution and (S)-2-phenylbenzoxazole enantiomers exhibited vastly improved brain clearance with washout ratios higher than 20...
October 15, 2016: Molecular Pharmaceutics
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