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https://www.readbyqxmd.com/read/28213437/%C3%AE-synuclein-multiple-system-atrophy-prions
#1
Amanda L Woerman, Joel C Watts, Atsushi Aoyagi, Kurt Giles, Lefkos T Middleton, Stanley B Prusiner
Multiple system atrophy (MSA) is a rapidly progressive neurodegenerative disease arising from the misfolding and accumulation of the protein α-synuclein in oligodendrocytes, where it forms glial cytoplasmic inclusions (GCIs). Several years of studying synthetic α-synuclein fibrils has provided critical insight into the ability of α-synuclein to template endogenous protein misfolding, giving rise to fibrillar structures capable of propagating from cell to cell. However, more recent studies with MSA-derived α-synuclein aggregates have shown that they have a similar ability to undergo template-directed propagation, like PrP prions...
February 17, 2017: Cold Spring Harbor Perspectives in Medicine
https://www.readbyqxmd.com/read/28212282/collagen-gold-nanoparticle-conjugates-for-versatile-biosensing
#2
Sarah Unser, Samuel Holcomb, ReJeana Cary, Laura Sagle
Integration of noble metal nanoparticles with proteins offers promising potential to create a wide variety of biosensors that possess both improved selectivity and versatility. The multitude of functionalities that proteins offer coupled with the unique optical properties of noble metal nanoparticles can allow for the realization of simple, colorimetric sensors for a significantly larger range of targets. Herein, we integrate the structural protein collagen with 10 nm gold nanoparticles to develop a protein-nanoparticle conjugate which possess the functionality of the protein with the desired colorimetric properties of the nanoparticles...
February 15, 2017: Sensors
https://www.readbyqxmd.com/read/28211492/the-propensity-of-the-bacterial-rodlin-protein-rdlb-to-form-amyloid-fibrils-determines-its-function-in-streptomyces-coelicolor
#3
Wen Yang, Joost Willemse, Elizabeth B Sawyer, Fei Lou, Weibin Gong, Hong Zhang, Sally L Gras, Dennis Claessen, Sarah Perrett
Streptomyces bacteria form reproductive aerial hyphae that are covered with a pattern of pairwise aligned fibrils called rodlets. The presence of the rodlet layer requires two homologous rodlin proteins, RdlA and RdlB, and the functional amyloid chaplin proteins, ChpA-H. In contrast to the redundancy shared among the eight chaplins, both RdlA and RdlB are indispensable for the establishment of this rodlet structure. By using a comprehensive biophysical approach combined with in vivo characterization we found that RdlB, but not RdlA, readily assembles into amyloid fibrils...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28207276/hydrophobic-nanoparticles-reduce-the-%C3%AE-sheet-content-of-sevi-amyloid-fibrils-and-inhibit-sevi-enhanced-hiv-infectivity
#4
Daniel A Sheik, Jeffrey M Chamberlain, Lauren R Brooks, Melissa L Clark, Young Hun Kim, Geoffray Leriche, Clifford P Kubiak, Stephen Dewhurst, Jerry Yang
Semen-Derived Enhancer of Virus Infection (SEVI) fibrils are naturally abundant amyloid aggregates found in semen that facilitate viral attachment and internalization of HIV in cells, thereby increasing the probability of infection. Mature SEVI fibrils are comprised of aggregated peptides exhibiting high β-sheet secondary structural characteristics. Herein, we show that polymers containing hydrophobic side chains can interact with SEVI and reduce its β-sheet content by ~45% compared to the β-sheet content of SEVI in the presence of polymers with hydrophilic side chains, as estimated by Polarization Modulation-Infrared Reflectance Absorption Spectroscopy Measurements...
February 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28204916/-remodeling-of-the-aging-heart-sinus-node-dysfunction-and-atrial-fibrillation
#5
Jörg Weirich
The incidence of both sinus node dysfunction (SND) and atrial fibrillation (AF) increases with age. SND and AF frequently coexist. Likewise, they are often associated with cardiovascular diseases. Both arrhythmias share similar pathomechanisms such as structural and functional remodeling, i. e., degenerative fibrosis and altered Ca(2+) handling, respectively. A growing body of evidence suggests an important role for the CamKII (Ca(2+)/calmodulin-dependent protein kinase II) in structural as well as in functional remodeling...
February 15, 2017: Herzschrittmachertherapie & Elektrophysiologie
https://www.readbyqxmd.com/read/28198135/hierarchically-ordered-polymer-nanofiber-shish-kebabs-as-a-bone-scaffold-material
#6
Xi Chen, Sarah E Gleeson, Tony Yu, Nasreen Khan, Robert W Yucha, Michele Marcolongo, Christopher Y Li
The ideal bone scaffold harnesses the body's ability to regenerate bone in critical size defects. A potential strategy to design the ideal bone scaffold is to mimic the natural structure of bone at the molecular level. The orientation and spatial distribution of nanocrystals in the organic matrix are two important and distinctive structural characteristics associated with natural bone. There has yet to be a synthetic system or scaffold that is able to control both the spatial distribution and orientation of the HAP crystalline structure...
February 15, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28197356/acute-pseudoischemic-ecg-abnormalities-after-right-pneumonectomy
#7
Nada Vasic, Sanja Dimic-Janjic, Ruza Stevic, Branislava Milenkovic, Verica Djukanovic
New onset of electrocardiographic (ECG) abnormalities can occur after lung surgery due to the changes in the position of structures and organs in the chest cavity. The most common heart rhythm disorder is atrial fibrillation. So-called "pseudoischemic" ECG changes that mimic classic ECG signs of acute myocardial ischemia are also often noticed. We report the case of a 68-year-old male, with no prior cardiovascular disease, who underwent extensive surgical resection for lung cancer. On a second postoperative day, clinical and electrocardiographic signs of acute myocardial ischemia occurred...
2017: Case Reports in Surgery
https://www.readbyqxmd.com/read/28196797/left-atrial-structure-in-relationship-to-age-sex-ethnicity-and-cardiovascular-risk-factors-mesa-multi-ethnic-study-of-atherosclerosis
#8
Filip Zemrak, Bharath Ambale-Venkatesh, Gabriella Captur, Jonathan Chrispin, Ela Chamera, Mohammadali Habibi, Saman Nazarian, Saidi A Mohiddin, James C Moon, Steffen E Petersen, João A C Lima, David A Bluemke
BACKGROUND: Left atrial (LA) size is a marker of diastolic function and is associated with atrial fibrillation and cardiovascular outcomes. However, there are no large population studies measuring LA structure. The relationship of demographics and cardiovascular risk factors to LA size is largely unknown. This study aimed to determine associations of LA size with demographic factors, cardiac structure and function, and cardiovascular risk factors. METHODS AND RESULTS: LA volume indexed to body surface area was measured by cardiovascular magnetic resonance steady-state free precession and fast gradient echo cine long- and short-axis images in 2576 asymptomatic participants of MESA ([Multi-Ethnic Study of Atherosclerosis] 68...
February 2017: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28196296/age-related-reduction-of-dermal-fibroblast-size-up-regulates-multiple-matrix-metalloproteinases-as-observed-in-aged-human-skin-in-vivo
#9
Z Qin, R M Balimunkwe, T Quan
BACKGROUND: Fragmentation of collagen fibrils, the major structure protein in skin, is a hallmark of dermal aging. Matrix metalloproteinases (MMPs) are largely responsible for fragmentation of collagen fibrils. However, the alteration of all known mammalian MMPs and the mechanism underlying altered expression of MMPs in chronologically aged human skin are less understood. OBJECTIVES: To quantify gene expression of all 23 known mammalian MMPs in sun-protected young and aged human skin in vivo, and investigate the potential mechanism underlying age-related alteration of multiple MMPs...
February 14, 2017: British Journal of Dermatology
https://www.readbyqxmd.com/read/28192290/site-specific-structural-dynamics-of-%C3%AE-synuclein-revealed-by-time-resolved-fluorescence-spectroscopy-a-review
#10
Shruti Sahay, G Krishnamoorthy, Samir K Maji
Aggregation of α-Synuclein (α-Syn) into amyloid fibrils is known to be associated with the pathogenesis of Parkinson's disease (PD). Several missense mutations of the α-Syn gene have been associated with rare, early onset familial forms of PD. Despite several studies done so far, the local/residue-level structure and dynamics of α-Syn in its soluble and aggregated fibril form and how these are affected by the familial PD associated mutations are still not clearly understood. Here, we review studies performed by our group as well as other research groups, where time-resolved fluorescence spectroscopy has been used to understand the site-specific structure and dynamics of α-Syn under physiological conditions as well as under conditions that alter the aggregation properties of the protein such as low pH, high temperature, presence of membrane mimics and familial PD associated mutations...
October 11, 2016: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28187308/light-driven-porphyrin-modulating-fibrillation-of-hiapp20-29-peptide
#11
Guodong Yang, Lei Liu, Jie Wang, Christian Bortolini, Mingdong Dong
The human Islet amyloid polypeptide (20-29) (hIAPP20-29) is considered to be the core fibrillating fragment of hIAPP, which is associated with the pathogenesis of Type-II diabetes mellitus. A current challenge is the discovery of an efficient way to modulate amyloid aggregation and inhibit the toxicity of its aggregates. In this work, photoexcited porphyrins are successfully used to inhibit the fibrillation of hIAPP20-29. Insights on the inhibitory mechanism are explored by the analysis of the secondary structure, the morphology and the mechanical properties of amyloid aggregates...
January 25, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28187186/structural-coalescence-underlies-the-aggregation-propensity-of-a-%C3%AE-barrel-protein-motif
#12
Carla R Angelani, Julio J Caramelo, Lucrecia M Curto, José M Delfino
A clear understanding of the structural foundations underlying protein aggregation is an elusive goal of central biomedical importance. A step toward this aim is exemplified by the β-barrel motif represented by the intestinal fatty acid binding protein (IFABP) and two abridged all-β sheet forms (Δ98Δ and Δ78Δ). At odds with the established notion that a perturbation of the native fold should necessarily favor a buildup of intermediate forms with an enhanced tendency to aggregate, the intrinsic stability (ΔG°H2O) of these proteins does not bear a straightforward correlation with their trifluoroethanol (TFE)-induced aggregation propensity...
2017: PloS One
https://www.readbyqxmd.com/read/28185264/amyloidogenicity-and-toxicity-of-the-reverse-and-scrambled-variants-of-amyloid-%C3%AE-1-42
#13
Devkee M Vadukul, Oyinkansola Gbajumo, Karen E Marshall, Louise C Serpell
β-amyloid 1-42 (Aβ1-42) is a self-assembling peptide that goes through many conformational and morphological changes before forming the fibrils that are deposited in extracellular plaques characteristic of Alzheimer's disease. The link between Aβ1-42 structure and toxicity is of major interest, in particular, the neurotoxic potential of oligomeric species. Many studies utilise reversed (Aβ42-1) and scrambled (AβS) forms of amyloid-β as control peptides. Here, using circular dichroism, Thioflavin T fluorescence and transmission electron microscopy, we reveal that both control peptides self-assemble to fibres within 24 hours...
February 10, 2017: FEBS Letters
https://www.readbyqxmd.com/read/28183844/association-between-posterior-left-atrial-adipose-tissue-mass-and-atrial-fibrillation
#14
Alexander R van Rosendael, Aukelien C Dimitriu-Leen, Philippe J van Rosendael, Melissa Leung, Jeff M Smit, Antti Saraste, Juhani Knuuti, Rob J van der Geest, Britt W H van der Arend, Erik W van Zwet, Arthur J Scholte, Victoria Delgado, Jeroen J Bax
BACKGROUND: Epicardial adipose tissue located close to the atrial wall can change the electric conduction of the left atrium, potentially leading to atrial fibrillation (AF). The aim of this study was to assess whether an increased atrial adipose tissue mass posterior to the left atrium is related to AF independent of demographical and cardiovascular risk factors. METHODS AND RESULTS: Two hundred patients with AF and 200 patients without AF who underwent computed tomographic angiography were included...
February 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28183246/solid-state-structure-of-abeta-ab-in-alzheimer-s-disease
#15
Junxia Lu, Xing-Qi Dong, Jian-Jun Zhang
Alzheimer's disease (AD) has become the most common neurodegenerative disease. The deposition of amyloid fibrils in the brain is one of the characteristics of AD. The fibrils are composed of amyloid-b peptide (Ab). Ab is produced through a series event of protease cleavage of a transmembrane protein called β-amyloid precursor protein (APP) which is commonly expressed in the brain. The production of Ab and its propensity to aggregation to form oligomers and fibrils are believed to initiate a sequence of events that lead to AD dementia...
February 8, 2017: Protein and Peptide Letters
https://www.readbyqxmd.com/read/28182862/proanthocyanidins-loaded-nanoparticles-enhance-dentin-degradation-resistance
#16
A S Fawzy, B M Priyadarshini, S T Selvan, T B Lu, J Neo
Previous studies reported that grapeseed extract (GSE), which is rich in proanthocyanidins (PAs), improves the biodegradation resistance of demineralized dentin. This study aimed to investigate the effect of a new GSE delivery strategy to demineralized dentin through loading into biodegradable polymer poly-[lactic-co-glycolic acid] (PLGA) nanoparticles on the biodegradation resistance in terms of structural stability and surface/bulk mechanical and biochemical properties with storage time in collagenase-containing solutions...
February 1, 2017: Journal of Dental Research
https://www.readbyqxmd.com/read/28180219/super-resolution-imaging-of-alpha-synuclein-polymorphisms-and-their-potential-role-in-neurodegeneration
#17
REVIEW
Eileen Nugent, Clemens F Kaminski, Gabriele S Kaminski Schierle
The conversion of soluble, functional proteins into amyloid fibrils has been linked to the development of neurodegenerative disorders, including Parkinson's and Alzheimer's disease. In the brains of patients with these disorders, the increasing presence of amyloid-containing plaques corresponds to neuronal cell death and the worsening of symptoms. However, protein amyloids are not merely confined to dying cells. Rather, some show a propensity to be transmitted to, and enter adjacent cells and induce the polymerization of the native monomer population...
February 9, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
https://www.readbyqxmd.com/read/28179613/left-atrial-appendage-thrombi-formation-in-japanese-non-valvular-atrial-fibrillation-patients-during-anticoagulation-therapy%C3%A3-warfarin-vs-direct-oral-anticoagulants
#18
Mihoko Kawabata, Masahiko Goya, Takeshi Sasaki, Shingo Maeda, Yasuhiro Shirai, Takuro Nishimura, Takakatsu Yoshitake, Shinya Shiohira, Mitsuaki Isobe, Kenzo Hirao
BACKGROUND: Atrial fibrillation (AF) is a common cardiac arrhythmia, associated with increased cardiovascular morbidity and mortality including thromboembolic events. The aims of this study were to assess the prevalence of left atrial appendage (LAA) thrombi in Japanese non-valvular atrial fibrillation (NVAF) patients undergoing preprocedural transesophageal echocardiography (TEE) during anticoagulation therapy, and to compare the efficacy of warfarin and direct oral anticoagulants (DOAC)...
February 7, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/28178939/corneal-vesicles-accumulate-collagen-vi-associated-with-tissue-remodeling-in-apolipoprotein-a-i-deficiency-a-case-report
#19
Hiroyuki Namba, Mari Narumi, Shinji Susa, Rintaro Ohe, Takeo Kato, Mitsunori Yamakawa, Hidetoshi Yamashita
BACKGROUND: Apo A-I deficiency clinically shows low serum levels of HDL cholesterol and corneal opacity at a young age. Histopathological evaluations of affected corneas are not enough, and the mechanism of corneal opacity is still unclear. CASE PRESENTATION: A 61-year-old woman suffered from blurred vision with a corneal opacity. She had significantly reduced serum levels of high-density lipoprotein cholesterol and Apo A-I, stenosis of the coronary arteries, and ischemic heart failure...
February 8, 2017: BMC Ophthalmology
https://www.readbyqxmd.com/read/28177321/the-crystal-structure-of-pd1-a-haemophilus-surface-fibril-domain
#20
Jack Wright, Maren Thomsen, Robert Kolodziejczyk, Joshua Ridley, Jessica Sinclair, Glenn Carrington, Birendra Singh, Kristian Riesbeck, Adrian Goldman
The Haemophilus surface fibril (Hsf) is an unusually large trimeric autotransporter adhesin (TAA) expressed by the most virulent strains of H. influenzae. Hsf is known to mediate adhesion between pathogen and host, allowing the establishment of potentially deadly diseases such as epiglottitis, meningitis and pneumonia. While recent research has suggested that this TAA might adopt a novel `hairpin-like' architecture, the characterization of Hsf has been limited to in silico modelling and electron micrographs, with no high-resolution structural data available...
February 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
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