scholarly journals Trimeric Tau Is Toxic to Human Neuronal Cells at Low Nanomolar Concentrations

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Huilai Tian ◽  
Eliot Davidowitz ◽  
Patricia Lopez ◽  
Sharareh Emadi ◽  
James Moe ◽  
...  
Keyword(s):  
Splice Variants ◽  
Critical Role ◽  
Neuroblastoma Cells ◽  
Neuronal Loss ◽  
Synaptic Function ◽  
Human Neuroblastoma ◽  
Force Microscopy ◽  
Atomic Force ◽  
Therapeutic Development ◽  
Human Neuronal Cells

In Alzheimer’s disease (AD), tau aggregates into fibrils and higher order neurofibrillary tangles, a key histopathological feature of AD. However, soluble oligomeric tau species may play a more critical role in AD progression since these tau species correlate better with neuronal loss and cognitive dysfunction. Recent studies show that extracellular oligomeric tau can inhibit memory formation and synaptic function and also transmit pathology to neighboring neurons. However, the specific forms of oligomeric tau involved in toxicity are still unknown. Here, we used two splice variants of recombinant human tau and generated monomeric, dimeric, and trimeric fractions of each isoform. The composition of each fraction was verified chromatographically and also by atomic force microscopy. The toxicity of each fraction toward both human neuroblastoma cells and cholinergic-like neurons was assessed. Trimeric, but not monomeric or dimeric, tau oligomers of both splice variants were neurotoxic at low nanomolar concentrations. Further characterization of tau oligomer species with disease-specific modifications and morphologies is necessary to identify the best targets for the development of biomarker and therapeutic development for AD and related tauopathies.

scholarly journals ELASTICITY OF DIFFERENTIATED AND UNDIFFERENTIATED HUMAN NEUROBLASTOMA CELLS CHARACTERIZED BY ATOMIC FORCE MICROSCOPY

2015 ◽  
Vol 15 (05) ◽  
pp. 1550069 ◽  
Author(s):  
SHIJIA ZHAO ◽  
ALEX STAMM ◽  
JEONG SOON LEE ◽  
ALEXEI GRUVERMAN ◽  
JUNG YUL LIM ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Force Microscopy ◽  
Atomic Force ◽  
Neuroscience Research ◽  
Culture Model ◽  
Undifferentiated Cells

Human neuroblastoma (SH-SY5Y) cells, with its ability to differentiate into neurons, have been widely used as the in vitro cell culture model for neuroscience research, especially in studying the pathogenesis of Parkinson's disease (PD) and developing therapeutic strategies. Cellular elasticity could potentially serve as a biomarker to quantitatively distinguish undifferentiated and differentiated SH-SY5Y cells. The goal of this work is to characterize the retinoic acid (RA) induced alternations of elastic properties of SH-SY5Y cells using atomic force microscopy (AFM). The elasticity was measured at multiple points of a single cell. Results have shown that the differentiation of SH-SY5Y cell led to a larger elastic modulus, which is three times more than that of undifferentiated cells. A higher indentation rate applied during AFM measurements led to a larger elastic modulus of the cell. This work provides new insights into the differentiation process identified by the elasticity marker, which could be extended to investigate the function, health and ageing of cells.

scholarly journals All chemical YBa2Cu3O7 superconducting multilayers: Critical role of CeO2 cap layer flatness

2009 ◽  
Vol 24 (4) ◽  
pp. 1446-1455 ◽  
Author(s):  
M. Coll ◽  
J. Gàzquez ◽  
R. Huhne ◽  
B. Holzapfel ◽  
Y. Morilla ◽  
...  
Keyword(s):  
Critical Role ◽  
High Energy ◽  
Buffer Layers ◽  
Solution Deposition ◽  
Ybco Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Densities ◽  
Atomically Flat

New advances toward microstructural improvement of epitaxial CeO2 films grown by chemical solution deposition and their use as buffer layers for YBa2Cu3O7 (YBCO) films are presented. We demonstrate that the degree of epitaxy and the fraction of (001) atomically flat surface area are controlled by the incorporation of tetravalent (Zr4+) or trivalent (Gd3+) cations into the ceria lattice. The degree of epitaxy has been investigated by means of Rutherford backscattering spectroscopy-channeling and reflection high-energy electron diffraction, and a new methodology is also presented to quantify the fraction of (001) atomically flat area from atomic force microscopy images. Results are further correlated with the superconducting properties, microstructure, and texture of YBCO films grown by the trifluoroacetate route. A comparison with pulsed laser deposition and YBCO films grown on the same ceria layers is also presented. This growth procedure has allowed us to obtain all chemical multilayer films with controlled microstructure and critical current densities above 4 MA cm−2 at 77 K.

scholarly journals A Hybrid Nanoplatform of Graphene Oxide/Nanogold for Plasmonic Sensing and Cellular Applications at the Nanobiointerface

2019 ◽  
Vol 9 (4) ◽  
pp. 676 ◽  
Author(s):  
Lorena Cucci ◽  
Irina Naletova ◽  
Giuseppe Consiglio ◽  
Cristina Satriano
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Microscopy Imaging ◽  
Human Neuroblastoma ◽  
Force Microscopy ◽  
Atomic Force ◽  
Plasmonic Sensing ◽  
One Step ◽  
Spherical Gold Nanoparticles ◽  
Species Production

In this study, nanocomposites of spherical gold nanoparticles (AuNPs) and graphene oxide (GO) nanosheets were fabricated by a simple one-step reduction method. The characterisation by UV-visible spectroscopy of the plasmonic sensing properties pointed out to a strong interaction between graphene and metal nanoparticles in the hybrid GO-AuNP, as confirmed by nuclear magnetic resonance. Moreover, atomic force microscopy analyses demonstrated that the gold nanoparticles were mostly confined to the basal planes of the GO sheets. The response of the nanoassemblies at the biointerface with human neuroblastoma SH-SY5Y cell line was investigated in terms of nanotoxicity as well as of total and mitochondrial reactive oxygen species production. Confocal microscopy imaging of cellular internalization highlighted the promising potentialities of GO-AuNP nanoplatforms for theranostic (i.e., sensing/imaging + therapy) applications.

scholarly journals Theranostic Nanoplatforms of Thiolated Reduced Graphene Oxide Nanosheets and Gold Nanoparticles

2020 ◽  
Vol 10 (16) ◽  
pp. 5529 ◽  
Author(s):  
Pascal Tomasella ◽  
Vanessa Sanfilippo ◽  
Carmela Bonaccorso ◽  
Lorena Maria Cucci ◽  
Giuseppe Consiglio ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Density Functional ◽  
Metal Salt ◽  
Colorimetric Assay ◽  
Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Force Microscopy ◽  
Vis Spectroscopy

In this study, graphene oxide (GO) and reduced-thiolated GO (rGOSH) were used as 2D substrate to fabricate nanocomposites with nanoparticles of gold nanospheres (AuNS) or nanorods (AuNR), via in situ reduction of the metal salt precursor and seed-mediated growth processes. The plasmonic sensing capability of the gold-decorated nanosheets were scrutinized by UV-visible (UV-VIS) spectroscopy. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analyses (TGA), and atomic force microscopy (AFM) were performed in order to prove the actual reduction that occurred concomitantly with the thiolation of GO, the increase in the hydrophobic character as well as the size, and preferential gathering of the gold nanoparticles onto the nanosheet substrates, respectively. Moreover, the theoretical electronic and infrared absorption (UV-VIS and IR) spectra were calculated within a time-dependent approach of density functional theory (DFT). Eventually, in vitro cellular experiments on human neuroblastoma cells (SH-SY5Y line) were carried out in order to evaluate the nanotoxicity of the nanocomposites by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction (MTT) colorimetric assay. Results pointed out the promising potential of these hybrids as plasmonic theranostic platforms with different hydrophilic or hydrophobic features as well as cytotoxic effects against cancer cells.

scholarly journals Alternatively Spliced Methionine Synthase in SH-SY5Y Neuroblastoma Cells: Cobalamin and GSH Dependence and Inhibitory Effects of Neurotoxic Metals and Thimerosal

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mostafa Waly ◽  
Verna-Ann Power-Charnitsky ◽  
Nathaniel Hodgson ◽  
Alok Sharma ◽  
Tapan Audhya ◽  
...  
Keyword(s):  
Neuroblastoma Cells ◽  
Methionine Synthase ◽  
Protein Species ◽  
Inhibitory Effects ◽  
Human Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Highly Sensitive ◽  
Alternatively Spliced ◽  
Human Neuronal Cells ◽  
Rate Limiting

The folate and cobalamin (Cbl-) dependent enzyme methionine synthase (MS) is highly sensitive to oxidation and its activity affects all methylation reactions. Recent studies have revealed alternative splicing of MS mRNA in human brain and patient-derived fibroblasts. Here we show that MS mRNA in SH-SY5Y human neuroblastoma cells is alternatively spliced, resulting in three primary protein species, thus providing a useful model to examine cofactor dependence of these variant enzymes. MS activity was dependent upon methylcobalamin (MeCbl) or the combination of hydroxocobalamin (OHCbl) and S-adenosylmethionine (SAM). OHCbl-based activity was eliminated by depletion of the antioxidant glutathione (GSH) but could be rescued by provision of either glutathionylcobalamin (GSCbl) or MeCbl. Pretreatment of cells with lead, arsenic, aluminum, mercury, or the ethylmercury-containing preservative thimerosal lowered GSH levels and inhibited MS activity in association with decreased uptake of cysteine, which is rate-limiting for GSH synthesis. Thimerosal treatment decreased cellular levels of GSCbl and MeCbl. These findings indicate that the alternatively spliced form of MS expressed in SH-SY5Y human neuronal cells is sensitive to inhibition by thimerosal and neurotoxic metals, and lower GSH levels contribute to their inhibitory action.

scholarly journals Critical role for Piccolo in synaptic vesicle retrieval

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Frauke Ackermann ◽  
Kay Oliver Schink ◽  
Christine Bruns ◽  
Zsuzsanna Izsvák ◽  
F Kent Hamra ◽  
...  
Keyword(s):  
Active Zone ◽  
Synaptic Vesicles ◽  
Critical Role ◽  
Neuronal Loss ◽  
Synaptic Function ◽  
Loss Of Function ◽  
Pontocerebellar Hypoplasia ◽  
Over Expression ◽  
Early Endosomes ◽  
Type 3

Loss of function of the active zone protein Piccolo has recently been linked to a disease, Pontocerebellar Hypoplasia type 3, which causes brain atrophy. Here, we address how Piccolo inactivation in rat neurons adversely affects synaptic function and thus may contribute to neuronal loss. Our analysis shows that Piccolo is critical for the recycling and maintenance of synaptic vesicles. We find that boutons lacking Piccolo have deficits in the Rab5/EEA1 dependent formation of early endosomes and thus the recycling of SVs. Mechanistically, impaired Rab5 function was caused by reduced synaptic recruitment of Pra1, known to interact selectively with the zinc finger domains of Piccolo. Importantly, over-expression of GTPase deficient Rab5 or the Znf1 domain of Piccolo restores the size and recycling of SV pools. These data provide a molecular link between the active zone and endosome sorting at synapses providing hints to how Piccolo contributes to developmental and psychiatric disorders.

scholarly journals Genome-wide screen identifies curli amyloid fibril as a bacterial component promoting host neurodegeneration

2021 ◽  
Vol 118 (34) ◽  
pp. e2106504118
Author(s):  
Chenyin Wang ◽  
Chun Yin Lau ◽  
Fuqiang Ma ◽  
Chaogu Zheng
Keyword(s):  
Amyloid Fibril ◽  
Critical Role ◽  
Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
C Elegans ◽  
Host Interaction ◽  
Genome Wide ◽  
A Genome ◽  
Bacterial Genes ◽  
Neuronal Functions

Growing evidence indicates that gut microbiota play a critical role in regulating the progression of neurodegenerative diseases such as Parkinson’s disease. The molecular mechanism underlying such microbe–host interaction is unclear. In this study, by feeding Caenorhabditis elegans expressing human α-syn with Escherichia coli knockout mutants, we conducted a genome-wide screen to identify bacterial genes that promote host neurodegeneration. The screen yielded 38 genes that fall into several genetic pathways including curli formation, lipopolysaccharide assembly, and adenosylcobalamin synthesis among others. We then focused on the curli amyloid fibril and found that genetically deleting or pharmacologically inhibiting the curli major subunit CsgA in E. coli reduced α-syn–induced neuronal death, restored mitochondrial health, and improved neuronal functions. CsgA secreted by the bacteria colocalized with α-syn inside neurons and promoted α-syn aggregation through cross-seeding. Similarly, curli also promoted neurodegeneration in C. elegans models of Alzheimer’s disease, amyotrophic lateral sclerosis, and Huntington’s disease and in human neuroblastoma cells.

Subnanometer-scale imaging of nanobio-interfaces by frequency modulation atomic force microscopy

2020 ◽  
Vol 48 (4) ◽  
pp. 1675-1682
Author(s):  
Takeshi Fukuma
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Critical Role ◽  
Surface Structures ◽  
Scale Model ◽  
Dynamic Mode ◽  
Biological Applications ◽  
Scanning Method ◽  
Force Microscopy ◽  
Atomic Force

Recently, there have been significant advancements in dynamic-mode atomic force microscopy (AFM) for biological applications. With frequency modulation AFM (FM-AFM), subnanometer-scale surface structures of biomolecules such as secondary structures of proteins, phosphate groups of DNAs, and lipid-ion complexes have been directly visualized. In addition, three-dimensional AFM (3D-AFM) has been developed by combining a high-resolution AFM technique with a 3D tip scanning method. This method enabled visualization of 3D distributions of water (i.e. hydration structures) with subnanometer-scale resolution on various biological molecules such as lipids, proteins, and DNAs. Furthermore, 3D-AFM also allows visualization of subnanometer-scale 3D distributions of flexible surface structures such as thermally fluctuating lipid headgroups. Such a direct local information at nano-bio interfaces can play a critical role in determining the atomic- or molecular-scale model to explain interfacial structures and functions. Here, we present an overview of these recent advancements in the dynamic-mode AFM techniques and their biological applications.

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