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amyloid precursor protein

Anat Elmann, Alona Telerman, Rivka Ofir, Yoel Kashman, Orly Lazarov
Alzheimer's disease (AD) is the most prevalent cause of dementia in adults. Current available drugs for AD transiently alleviate some of the symptoms, but do not modify the disease mechanism or cure it. Therefore, new drugs are desperately needed. Key contributors to AD are amyloid beta (Aβ)- and reactive oxygen species (ROS)-induced cytotoxicities. Plant-derived substances have been shown to affect various potential targets in various diseases including AD. Therefore, phytochemicals which can protect neuronal cells against these insults might help in preventing and treating this disease...
March 15, 2018: Journal of Natural Medicines
Misato Yoshikawa, Yoshiyuki Soeda, Makoto Michikawa, Osborne F X Almeida, Akihiko Takashima
Hippocampal hyperactivity, ascribed to amyloid β (Aβ)-induced imbalances in neural excitation and inhibition, is found in patients with mild cognitive impairment, a prodromal stage of Alzheimer's disease (AD). To better understand the relationship between hippocampal hyperactivity and the molecular triggers of behavioral impairments in AD, we used Mn-enhanced MRI (MEMRI) to assess neuronal activity after subjecting mice to a task requiring spatial learning and memory. Depletion of endogenous tau in an amyloid precursor protein (APP) transgenic (J20) mouse line was shown to ameliorate hippocampal hyperactivity in J20 animals, tau depletion failed to reverse memory deficits associated with APP/Aβ overproduction...
2018: Frontiers in Neuroscience
Heather T Whittaker, Shenghua Zhu, Domenico L Di Curzio, Richard Buist, Xin-Min Li, Suzanna Noy, Frances K Wiseman, Jonathan D Thiessen, Melanie Martin
Alzheimer's disease (AD) pathology causes microstructural changes in the brain. These changes, if quantified with magnetic resonance imaging (MRI), could be studied for use as an early biomarker for AD. The aim of our study was to determine if T1 relaxation, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI) metrics could reveal changes within the hippocampus and surrounding white matter structures in ex vivo transgenic mouse brains overexpressing human amyloid precursor protein with the Swedish mutation...
March 12, 2018: Magnetic Resonance Imaging
Jodi R Paul, Hira A Munir, Thomas van Groen, Karen L Gamble
Disruption of circadian rhythms is commonly reported in individuals with Alzheimer's disease (AD). Neurons in the primary circadian pacemaker, the suprachiasmatic nucleus (SCN), exhibit daily rhythms in spontaneous neuronal activity which are important for maintaining circadian behavioral rhythms. Disruption of SCN neuronal activity has been reported in animal models of other neurodegenerative disorders; however, the effect of AD on SCN neurophysiology remains unknown. In this study we examined circadian behavioral and electrophysiological changes in a mouse model of AD, using male mice from the Tg-SwDI line which expresses human amyloid precursor protein with the familial Swedish (K670N/M671L), Dutch (E693Q), Iowa (D694N) mutations...
March 11, 2018: Neurobiology of Disease
Dennis de Coninck, Thomas H Schmidt, Jan-Gero Schloetel, Thorsten Lang
Plasma membrane proteins organize into structures named compartments, microdomains, rafts, phases, crowds, or clusters. These structures are often smaller than 100 nm in diameter. Despite their importance in many cellular functions, little is known about their inner organization. For instance, how densely are molecules packed? Being aware of the protein compaction may contribute to our general understanding of why such structures exist and how they execute their functions. In this study, we have investigated plasma membrane crowds formed by the amyloid precursor protein (APP), a protein well known for its involvement in Alzheimer's disease...
March 13, 2018: Biophysical Journal
Ivan Martinez-Valbuena, Irene Amat-Villegas, Rafael Valenti-Azcarate, Maria Del Mar Carmona-Abellan, Irene Marcilla, Maria-Teresa Tuñon, Maria-Rosario Luquin
Parkinson's disease patients experience a wide range of non-motor symptoms that may be provoked by deposits of phosphorylated α-synuclein in the peripheral nervous system. Pre-existing diabetes mellitus might be a risk factor for developing Parkinson's disease, and indeed, nearly 60% of Parkinson's disease patients are insulin resistant. Thus, we have investigated whether phosphorylated α-synuclein is deposited in pancreatic tissue of subjects with synucleinopathies. We studied pancreatic tissue from 39 subjects diagnosed with Parkinson's disease, Lewy body Dementia or incidental Lewy bodies disease, as well as that from 34 subjects with diabetes mellitus and a normal neuropathological examination, and 52 subjects with a normal neuropathological examination...
March 13, 2018: Acta Neuropathologica
Itay Cohen, Si Naftaly, Efrat Ben-Zeev, Alexandra Hockla, Evette S Radisky, Niv Papo
High structural and sequence similarity within protein families can pose significant challenges to the development of selective inhibitors, especially towards proteolytic enzymes. Such enzymes usually belong to large families of closely similar proteases and may also hydrolyze, with different rates, protein or peptide-based inhibitors. To address this challenge, we employed a combinatorial yeast surface display library approach complemented with a novel pre-equilibrium, competitive screening strategy for facile assessment of the effects of multiple mutations on inhibitor association rates and binding specificity...
March 13, 2018: Biochemical Journal
Aditi Wagle, Su Hui Seong, Bing Tian Zhao, Mi Hee Woo, Hyun Ah Jung, Jae Sue Choi
Hizikia fusiformis (Harvey) Okamura is a brown seaweed widely used in Korea and Japan, and it contains different therapeutically active constituents. In the present study, we investigated the activities of glycyrrhizin isolated from H. fusiformis, including its metabolites, 18α- and 18β-glycyrrhetinic acid against Alzheimer's disease (AD) via acetyl and butyrylcholinesterase and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibition. Among these three compounds, 18β-glycyrrhetinic acid (IC50  = 8...
March 12, 2018: Archives of Pharmacal Research
Frank Matthes, Moritz M Hettich, Judith Schilling, Diana Flores-Dominguez, Nelli Blank, Thomas Wiglenda, Alexander Buntru, Hanna Wolf, Stephanie Weber, Ina Vorberg, Alina Dagane, Gunnar Dittmar, Erich Wanker, Dan Ehninger, Sybille Krauss
Alzheimer's disease (AD) is characterized by two neuropathological hallmarks: senile plaques, which are composed of amyloid-β (Aβ) peptides, and neurofibrillary tangles, which are composed of hyperphosphorylated tau protein. Aβ peptides are derived from sequential proteolytic cleavage of the amyloid precursor protein (APP). In this study, we identified a so far unknown mode of regulation of APP protein synthesis involving the MID1 protein complex: MID1 binds to and regulates the translation of APP mRNA...
December 2018: Cell Death Discovery
J Chung, G Phukan, D Vergote, A Mohamed, M Maulik, M Stahn, R J Andrew, G Thinakaran, E Posse de Chaves, S Kar
Amyloid β (Aβ) peptide derived from amyloid precursor protein (APP) plays a critical role in the development of Alzheimer's disease. Current evidence indicates that altered levels/subcellular distribution of cholesterol can regulate Aβ production/clearance, but it remains unclear how cholesterol sequestration within the endosomal-lysosomal (EL) system can influence APP metabolism. Thus, we evaluated the effects of U18666A, which triggers cholesterol redistribution within EL system, on mouse N2a cells expressing different levels of APP in the presence or absence of extracellular cholesterol/lipids provided by fetal bovine serum (FBS)...
March 12, 2018: Molecular and Cellular Biology
Jessica G Rushton, Reinhard Ertl, Dieter Klein, Alexander Tichy, Barbara Nell
Objectives Feline diffuse iris melanoma (FDIM) is the most common malignant primary intraocular tumour in cats, with reported metastases rates between 19% and 63%. Currently, the only available diagnostic tool for a tentative diagnosis is histopathological examination of the enucleated eye. Therefore, the veterinary ophthalmologist is often faced with the dilemma of whether to enucleate an oftentimes visual eye or to continue monitoring, with the risk of metastases developing. In the past, cell-free DNA (cfDNA) gained more attention in human medicine, especially in the field of oncology...
March 1, 2018: Journal of Feline Medicine and Surgery
Miriam A Kael, Daniel K Weber, Frances Separovic, Marc-Antoine Sani
The cleavage of the amyloid precursor protein by β- and γ-secretases is a key event in Alzheimer's disease. A fusion protein was constructed to investigate the cleavage rate and aggregation kinetics of amyloid-beta (1-40) (Aβ(1-40)) peptides. The peptide was expressed with a Small Ubiquitin-Like Modifier (SUMO) on the N-terminus and cleaved by a SUMO protease Ulp1. The time course of the cleavage reaction was monitored by SDS-PAGE gel with 100:1 or 1000:1 SUMO-Aβ(1-40) to Ulp1 molar ratio and in the presence of brain total lipid extract unilamellar vesicles...
March 8, 2018: Biochimica et Biophysica Acta
Gaia Botteri, Laia Salvadó, Anna Gumà, D Lee Hamilton, Paul J Meakin, Gemma Montagut, Michael L J Ashford, Victoria Ceperuelo-Mallafré, Sonia Fernández-Veledo, Joan Vendrell, María Calderón-Dominguez, Dolors Serra, Laura Herrero, Javier Pizarro, Emma Barroso, Xavier Palomer, Manuel Vázquez-Carrera
OBJECTIVE: β-secretase/β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a key enzyme involved in Alzheimer's disease that has recently been implicated in insulin-independent glucose uptake in myotubes. However, it is presently unknown whether BACE1 and the product of its activity, soluble APPβ (sAPPβ), contribute to lipid-induced inflammation and insulin resistance in skeletal muscle cells. MATERIALS/METHODS: Studies were conducted in mouse C2C12 myotubes, skeletal muscle from Bace1-/- mice and mice treated with sAPPβ and adipose tissue and plasma from obese and type 2 diabetic patients...
March 8, 2018: Metabolism: Clinical and Experimental
Lisa Seipold, Hermann Altmeppen, Tomas Koudelka, Andreas Tholey, Petr Kasparek, Radislav Sedlacek, Michaela Schweizer, Julia Bär, Marina Mikhaylova, Markus Glatzel, Paul Saftig
A disintegrin and metalloproteinase 10 (ADAM10) plays a major role in the ectodomain shedding of important surface molecules with physiological and pathological relevance including the amyloid precursor protein (APP), the cellular prion protein, and different cadherins. Despite its therapeutic potential, there is still a considerable lack of knowledge how this protease is regulated. We have previously identified tetraspanin15 (Tspan15) as a member of the TspanC8 family to specifically associate with ADAM10...
March 8, 2018: Cellular and Molecular Life Sciences: CMLS
Tsuneya Ikezu, Cidi Chen, Annina M DeLeo, Ella Zeldich, M Daniele Fallin, Nicholas M Kanaan, Kathryn L Lunetta, Carmela R Abraham, Mark W Logue, Lindsay A Farrer
We studied the effect of two rare mutations (rs144662445 and rs149979685) in the A-kinase anchoring protein 9 (AKAP9) gene, previously associated with Alzheimer disease (AD) in African Americans (AA), on post-translational modifications of AD-related pathogenic molecules, amyloid precursor protein (APP) and microtubule-associated protein Tau using lymphoblastoid cell lines (LCLs) from 11 AA subjects with at least one AKAP9 mutation and 17 AA subjects lacking these mutations. LCLs were transduced by viral vectors expressing causative AD mutations in APP or human full-length wild type Tau...
March 7, 2018: Journal of Neuroimmune Pharmacology: the Official Journal of the Society on NeuroImmune Pharmacology
Ru-Yi Zhang, Lan Zhang, Li Zhang, Yu-Lan Wang, Lin Li
Alzheimer's disease (AD) is an irreversible neurodegenerative brain disorder with complex pathogenesis. Emerging evidence indicates that there is a tight relationship between mitochondrial dysfunction and β-amyloid (Aβ) formation. 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside (TSG) is one of the main active components extracted from Polygonum multiflorum. The purpose of the present study was to investigate the effects of TSG on Aβ production and neurotrophins in the brains of rats by using a mitochondrial dysfunction rat model induced by sodium azide (NaN3 ), an inhibitor of mitochondrial cytochrome c oxidase (COX)...
March 5, 2018: Journal of Natural Medicines
I A Kuznetsov, A V Kuznetsov
We develop a mathematical model that enables us to investigate possible mechanisms by which two primary markers of Alzheimer's disease (AD), extracellular amyloid plaques and intracellular tangles, may be related. Our model investigates the possibility that the decay of anterograde axonal transport of amyloid precursor protein (APP), caused by toxic tau aggregates, leads to decreased APP transport towards the synapse and APP accumulation in the soma. The developed model thus couples three processes: (i) slow axonal transport of tau, (ii) tau misfolding and agglomeration, which we simulated by using the Finke-Watzky model and (iii) fast axonal transport of APP...
February 2018: Proceedings. Mathematical, Physical, and Engineering Sciences
Stephanie Hartmann, Fang Zheng, Michele Constanze Kyncl, Sandra Karch, Kerstin Voelkl, Benedikt Zott, Carla D'Avanzo, Selene Lomoio, Giuseppina Tesco, Doo Yeon Kim, Christian Alzheimer, Tobias Huth
β-Secretase BACE1 is deemed a major culprit in Alzheimer's disease, but accumulating evidence indicates that there is more to the enzyme than driving the amyloidogenic processing of the amyloid precursor protein. For example, BACE1 has emerged as an important regulator of neuronal activity through proteolytic and, most unexpectedly, also through non-proteolytic interactions with several ion channels. Here, we identify and characterize the voltage-gated K+ channel 3.4 as a new and functionally relevant interaction partner of BACE1...
March 5, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Tao Xiong, Yi Qu, Huiqin Wang, Hongju Chen, Jianghu Zhu, Fengyan Zhao, Rong Zou, Li Zhang, Dezhi Mu
Glycogen synthase kinase 3 beta (GSK-3β) plays an important role in neurological outcomes after brain injury. However, its roles and mechanisms in hypoxia-ischemia (HI) are unclear. Activation of mTOR complex 1 (mTORC1) has been proven to induce the synthesis of proteins associated with regeneration. We hypothesized that GSK-3β inhibition could activate the mTORC1 signaling pathway, which may reduce axonal injury and induce synaptic protein synthesis and functional recovery of synapses after HI. By analyzing a P7 rat model of cerebral HI and an in vitro ischemic (oxygen glucose deprivation) model, we found that GSK-3β inhibitors (GSK-3β siRNA or lithium chloride) activated mTORC1 signaling, leading to increased expression of synaptic proteins, including synapsin 1, PSD95, and GluR1, and the microtubule-associated protein Tau and decreased expression of the axonal injury-associated protein amyloid precursor protein...
February 28, 2018: Journal of Neuropathology and Experimental Neurology
Maya L Gosztyla, Holly M Brothers, Stephen R Robinson
The amyloid-β (Aβ) peptide has long been considered to be the driving force behind Alzheimer's disease (AD). However, clinical trials that have successfully reduced Aβ burden in the brain have not slowed the cognitive decline, and in some instances, have resulted in adverse outcomes. While these results can be interpreted in different ways, a more nuanced picture of Aβ is emerging that takes into account the facts that the peptide is evolutionarily conserved and is present throughout life in cognitively normal individuals...
February 28, 2018: Journal of Alzheimer's Disease: JAD
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