scholarly journals Nano-Infrared Imaging of Primary Neurons

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2559
Author(s):  
Raul O. Freitas ◽  
Adrian Cernescu ◽  
Anders Engdahl ◽  
Agnes Paulus ◽  
João E. Levandoski ◽  
...  
Keyword(s):  
Structural Changes ◽  
Infrared Imaging ◽  
Near Field ◽  
Amyloid Β ◽  
Primary Neurons ◽  
Proof Of Concept ◽  
Cell Surfaces ◽  
Pathological Conditions ◽  
Β Sheet

Alzheimer’s disease (AD) accounts for about 70% of neurodegenerative diseases and is a cause of cognitive decline and death for one-third of seniors. AD is currently underdiagnosed, and it cannot be effectively prevented. Aggregation of amyloid-β (Aβ) proteins has been linked to the development of AD, and it has been established that, under pathological conditions, Aβ proteins undergo structural changes to form β-sheet structures that are considered neurotoxic. Numerous intensive in vitro studies have provided detailed information about amyloid polymorphs; however, little is known on how amyloid β-sheet-enriched aggregates can cause neurotoxicity in relevant settings. We used scattering-type scanning near-field optical microscopy (s-SNOM) to study amyloid structures at the nanoscale, in individual neurons. Specifically, we show that in well-validated systems, s-SNOM can detect amyloid β-sheet structures with nanometer spatial resolution in individual neurons. This is a proof-of-concept study to demonstrate that s-SNOM can be used to detect Aβ-sheet structures on cell surfaces at the nanoscale. Furthermore, this study is intended to raise neurobiologists’ awareness of the potential of s-SNOM as a tool for analyzing amyloid β-sheet structures at the nanoscale in neurons without the need for immunolabeling.

scholarly journals Nanomedicine Against Aβ Aggregation by β–Sheet Breaker Peptide Delivery: In Vitro Evidence

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 572 ◽  
Author(s):  
Pederzoli ◽  
Ruozi ◽  
Duskey ◽  
Hagmeyer ◽  
Sauer ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Polymeric Nanoparticles ◽  
Therapeutic Option ◽  
Amyloid Β ◽  
Peptide Delivery ◽  
Cellular Toxicity ◽  
Free Peptide ◽  
Aβ Aggregation ◽  
Β Sheet

The accumulation of amyloid β (Aβ) triggers a cascade of toxic events in Alzheimer’s disease (AD). The KLVFF peptide can interfere with Aβ aggregation. However, the peptide suffers from poor bioavailability and the inability to cross the blood–brain barrier. In this work, we study the possibility of adopting nanomedicine to overcome KLVFF limits in biodistribution. We produced new engineered polymeric nanoparticles (NPs), and we evaluated the cellular toxicity of these NPs and validated that KVLFF peptides released by NPs show the same promising effects on AD pathology. Our results revealed the successful generation of KVLFF loaded NPs that, without significant effects on cell heath, are even more potent in reversing Aβ-induced pathologies compared to the free peptide. Therefore, NPs will significantly advance KVLFF treatment as a therapeutic option for AD.

Protective effects of β-sheet breaker α/β-hybrid peptide against amyloid β-induced neuronal apoptosis in vitro

2016 ◽  
Vol 89 (6) ◽  
pp. 888-900 ◽  
Author(s):  
Sourav Kumar ◽  
Ashim Paul ◽  
Sourav Kalita ◽  
Anup Kumar Ghosh ◽  
Bhubaneswar Mandal ◽  
...  
Keyword(s):  
Neuronal Apoptosis ◽  
Amyloid Β ◽  
Protective Effects ◽  
Hybrid Peptide ◽  
Β Sheet

Inhibition of Alzheimer's amyloid-β peptide aggregation and its disruption by a conformationally restricted α/β hybrid peptide

2015 ◽  
Vol 51 (12) ◽  
pp. 2245-2248 ◽  
Author(s):  
Ashim Paul ◽  
Krishna Chaitanya Nadimpally ◽  
Tanmay Mondal ◽  
Kishore Thalluri ◽  
Bhubaneswar Mandal
Keyword(s):  
Anthranilic Acid ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Peptide Aggregation ◽  
Hybrid Peptide ◽  
Conformationally Restricted ◽  
Β Sheet

A novel class of anthranilic acid containing a conformationally restricted β-sheet breaker α/β-hybrid peptide efficiently disrupts preformed fibrillar aggregates of Aβ1–40in vitro.

scholarly journals A novel β -sheet breaker, RS-0406, reverses amyloid β -induced cytotoxicity and impairment of long-term potentiation in vitro

2002 ◽  
Vol 137 (5) ◽  
pp. 676-682 ◽  
Author(s):  
Yasuhiro Nakagami ◽  
Satoko Nishimura ◽  
Takako Murasugi ◽  
Isao Kaneko ◽  
Masaki Meguro ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Long Term Potentiation ◽  
Term Potentiation ◽  
Β Sheet

scholarly journals Collagen hydrogel confinement of amyloid-β accelerates aggregation and reduces cytotoxic effects

2019 ◽  
Author(s):  
Laura W. Simpson ◽  
Gregory L. Szeto ◽  
Hacene Boukari ◽  
Theresa A. Good ◽  
Jennie B. Leach
Keyword(s):  
3D Culture ◽  
Amyloid Β ◽  
Correlation Spectroscopy ◽  
Great Promise ◽  
Culture Systems ◽  
Glass Substrates ◽  
Collagen Hydrogel ◽  
Β Sheet

AbstractAlzheimer’s disease (AD) is the most common form of dementia and is associated with the accumulation of amyloid-β (Aβ), a peptide whose aggregation has been associated with neurotoxicity. Drugs targeting Aβ have shown great promise in 2D in vitro models and mouse models, yet preclinical and clinical trials for AD have been highly disappointing. We propose that current in vitro culture systems for discovering and developing AD drugs have significant limitations; specifically, that Aβ aggregation is vastly different in these 2D cultures carried out on flat plastic or glass substrates vs. in a 3D environment, such as brain tissue, where Aβ confinement very likely alters aggregation kinetics and thermodynamics. In this work, we identified attenuation of Aβ cytotoxicity in 3D hydrogel culture compared to 2D cell culture. We investigated Aβ structure and aggregation in solution vs. hydrogel using Transmission Electron Microscopy (TEM), Fluorescence Correlation Spectroscopy (FCS), and Thioflavin T (ThT) assays. Our results reveal that the equilibrium is shifted to stable β-sheet aggregates in hydrogels and away from the relatively unstable/unstructured presumed toxic oligomeric Aβ species in solution. Volume exclusion imparted by hydrogel confinement stabilizes unfolded, presumably toxic species, promoting stable extended β-sheet fibrils. These results, taken together with the many recent reports that 3D hydrogel cell cultures enable cell morphologies and epigenetic changes that are more similar to cells in vivo compared to 2D cultures, strongly suggest that AD drugs should be tested in 3D culture systems as a step along the development pathway towards new, more effective therapeutics.

The p3 Peptide, a Naturally Occurring Fragment of the Amyloid-β Peptide (Aβ)Found in Alzheimer's Disease, Has a Greater Aggregation Propensity In Vitro Than Full-Length Aβ, But Does Not Bind Cu2+.

2000 ◽  
Vol 53 (4) ◽  
pp. 321 ◽  
Author(s):  
Feda Ali ◽  
Andrew J. Thompson ◽  
Colin J. Barrow
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Down's Syndrome ◽  
Amyloid Β ◽  
Down’S Syndrome ◽  
Full Length ◽  
Amyloid Β Peptide ◽  
Sheet Structure ◽  
Β Sheet

Cerebellar preamyloid from both Down’s syndrome and Alzheimer’s disease contains the p3 fragment (Aβ 17–40/42) as a major amyloid-β peptide (Aβ) component. The p3 peptide was previously shown to form amyloid in vitro, but less readily than full-length Aβ. Here we show that the p3 peptide has a greater β-sheet-forming propensity than full-length Aβ. Using circular dichroism spectroscopy we determined that in aqueous solutions the p3 peptide forms β-sheet structure more readily than full-length Aβ. The p3 peptide also has a lower α-helical propensity than full-length Aβ in the structure-forming solvent trifluoroethanol. These results indicate that the lower amyloidogenicity of the p3 peptide is not related to an inability to form β-sheet structure. In this study we also show that, unlike full-length Aβ, the p3 peptide does not bind Cu2+ ions. This inability to bind copper ions may explain why the p3 peptide appears to play a lesser role in Down’s syndrome and Alzheimer’s disease related neurodegeneration than does full-length Aβ.

scholarly journals Attenuation of Oxidative Stress by Cannabinoids and Cannabis Extracts in Differentiated Neuronal Cells

2020 ◽  
Vol 13 (11) ◽  
pp. 328
Author(s):  
Aruna Raja ◽  
Soha Ahmadi ◽  
Fernanda de Costa ◽  
Nan Li ◽  
Kagan Kerman
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Neuronal Cells ◽  
In Vitro Models ◽  
Proof Of Concept ◽  
In Vitro System ◽  
Pathological Conditions ◽  
Stress Therapy ◽  
Antagonist Effect

In this proof-of-concept study, the antioxidant activity of phytocannabinoids, namely cannabidiol (CBD) and Δ9- tetrahydrocannabinol (THC), were investigated using an in vitro system of differentiated human neuronal SY-SH5Y cells. The oxidative stress was induced by hydrogen peroxide, as reactive oxygen species (ROS). Alzheimer’s disease (AD)-like pathological conditions were mimicked in vitro by treating the differentiated neuronal cells with amyloid-β1–42 (Aβ1–42) in the presence of Cu(II). We showed that THC had a high potency to combat oxidative stress in both in vitro models, while CBD did not show a remarkable antioxidant activity. The cannabis extracts also exhibited a significant antioxidant activity, which depended on the ratio of the THC and CBD. However, our results did not suggest any antagonist effect of the CBD on the antioxidant activity of THC. The effect of cannabis extracts on the cell viability of differentiated human neuronal SY-SH5Y cells was also investigated, which emphasized the differences between the bioactivity of cannabis extracts due to their composition. Our preliminary results demonstrated that cannabis extracts and phytocannabinoids have a promising potential as antioxidants, which can be further investigated to develop novel pharmaceuticals targeting oxidative stress therapy.

scholarly journals Albumin Alters the Conformational Ensemble of Amyloid-β by Promiscuous Interactions: Implications for Amyloid Inhibition

2021 ◽  
Vol 7 ◽  
Author(s):  
Huisi Xie ◽  
Cong Guo
Keyword(s):  
Therapeutic Potential ◽  
Amyloid Β ◽  
Conformational Space ◽  
Conformational Ensemble ◽  
Salt Bridges ◽  
Intrinsically Disordered ◽  
Domain Iii ◽  
Dynamics Simulations ◽  
Β Sheet

Human serum albumin (HSA) is a key endogenous inhibitor of amyloid-β (Αβ) aggregation. In vitro HSA inhibits Aβ fibrillization and targets multiple species along the aggregation pathway including monomers, oligomers, and protofibrils. Amyloid inhibition by HSA has both pathological implications and therapeutic potential, but the underlying molecular mechanism remains elusive. As a first step towards addressing this complex question, we studied the interactions of an Aβ42 monomer with HSA by molecular dynamics simulations. To adequately sample the conformational space, we adapted the replica exchange with solute tempering (REST2) method to selectively heat the Aβ42 peptide in the absence and presence of HSA. Aβ42 binds to multiple sites on HSA with a preference to domain III and adopts various conformations that all differ from the free state. The β-sheet abundances of H14-E22 and A30-M33 regions are significantly reduced by HSA, so are the β-sheet lengths. HSA shifts the conformational ensemble towards more disordered states and alters the β-sheet association patterns. In particular, the frequent association of Q15-V24 and N27-V36 regions into β-hairpin which is critical for aggregation is impeded. HSA primarily interacts with the latter β-region and the N-terminal charged residues. They form promiscuous interactions characterized by salt bridges at the edge of the peptide-protein interface and hydrophobic cores at the center. Consequently, intrapeptide interactions crucial for β-sheet formation are disrupted. Our work builds the bridge between the modification of Aβ conformational ensemble and amyloid inhibition by HSA. It also illustrates the potential of the REST2 method in studying interactions between intrinsically disordered peptides and globular proteins.

scholarly journals Au23(CR)14 nanocluster restores fibril Aβ’s unfolded state with abolished cytotoxicity and dissolves endogenous Aβ plaques

2019 ◽  
Vol 7 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Wenkang Zhang ◽  
Guanbin Gao ◽  
Zhongjie Ma ◽  
Zhuoying Luo ◽  
Meng He ◽  
...  
Keyword(s):  
Brain Slices ◽  
Amyloid Β ◽  
Aβ Oligomers ◽  
Aβ Peptides ◽  
Unfolded State ◽  
Good Biocompatibility ◽  
Aβ Fibrils ◽  
Soluble Aβ Oligomers ◽  
Β Sheet

Abstract The misfolding of amyloid-β (Aβ) peptides from the natural unfolded state to β-sheet structure is a critical step, leading to abnormal fibrillation and formation of endogenous Aβ plaques in Alzheimer's disease (AD). Previous studies have reported inhibition of Aβ fibrillation or disassembly of exogenous Aβ fibrils in vitro. However, soluble Aβ oligomers have been reported with increased cytotoxicity; this might partly explain why current clinical trials targeting disassembly of Aβ fibrils by anti-Aβ antibodies have failed so far. Here we show that Au23(CR)14 (a new Au nanocluster modified by Cys-Arg (CR) dipeptide) is able to completely dissolve exogenous mature Aβ fibrils into monomers and restore the natural unfolded state of Aβ peptides from misfolded β-sheets. Furthermore, the cytotoxicity of Aβ40 fibrils when dissolved by Au23(CR)14 is fully abolished. More importantly, Au23(CR)14 is able to completely dissolve endogenous Aβ plaques in brain slices from transgenic AD model mice. In addition, Au23(CR)14 has good biocompatibility and infiltration ability across the blood–brain barrier. Taken together, this work presents a promising therapeutics candidate for AD treatment, and manifests the potential of nanotechnological approaches in the development of nanomedicines.

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