Alzheimer’s β-Amyloid: Insights into Fibril Formation and Structure from Congo Red Binding

Inouye, Hideyo; Kirschner, Daniel A.

doi:10.1007/0-387-23226-5_10

Cited by 40 publications

(37 citation statements)

References 70 publications

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“…Although we cannot exclude the possibility that secreted ␣-synuclein exerts its toxic effects by uptake into recipient cells, in which it could impact cellular homeostasis in various ways, for example via disruption of protein degradation pathways (Sánchez et al, 2003;Inouye and Kirschner, 2005), the fact that these effects are more pronounced in neuronal cells in which limited uptake is detected raises the possibility that they are mediated extracellularly at the level of cell membrane. It is tempting to speculate that extracellular secreted ␣-synuclein could trigger degeneration via a specific signaling process.…”

Section: Discussionmentioning

confidence: 94%

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Cell-Produced α-Synuclein Is Secreted in a Calcium-Dependent Manner by Exosomes and Impacts Neuronal Survival

Emmanouilidou¹,

Melachroinou²,

Roumeliotis³

et al. 2010

J. Neurosci.

944

932

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␣-Synuclein is central in Parkinson's disease pathogenesis. Although initially ␣-synuclein was considered a purely intracellular protein, recent data suggest that it can be detected in the plasma and CSF of humans and in the culture media of neuronal cells. To address a role of secreted ␣-synuclein in neuronal homeostasis, we have generated wild-type ␣-synuclein and ␤-galactosidase inducible SH-SY5Y cells. Soluble oligomeric and monomeric species of ␣-synuclein are readily detected in the conditioned media (CM) of these cells at concentrations similar to those observed in human CSF. We have found that, in this model, ␣-synuclein is secreted by externalized vesicles in a calcium-dependent manner. Electron microscopy and liquid chromatography-mass spectrometry proteomic analysis demonstrate that these vesicles have the characteristic hallmarks of exosomes, secreted intraluminar vesicles of multivesicular bodies. Application of CM containing secreted ␣-synuclein causes cell death of recipient neuronal cells, which can be reversed after ␣-synuclein immunodepletion from the CM. High-and low-molecular-weight ␣-synuclein species, isolated from this CM, significantly decrease cell viability. Importantly, treatment of the CM with oligomer-interfering compounds before application rescues the recipient neuronal cells from the observed toxicity. Our results show for the first time that cell-produced ␣-synuclein is secreted via an exosomal, calcium-dependent mechanism and suggest that ␣-synuclein secretion serves to amplify and propagate Parkinson's diseaserelated pathology.

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Section: Discussionmentioning

confidence: 94%

“…In a number of studies, CR has been used to disrupt ␤-sheet-rich species, including ␣-synuclein, huntingtin, and A␤ (Heiser et al, 2000;Sánchez et al, 2003;Inouye and Kirschner, 2005). Indeed, CR dissociated the ␣-synuclein oligomeric species contained in the CM.…”

Section: Discussionmentioning

confidence: 99%

Cell-Produced α-Synuclein Is Secreted in a Calcium-Dependent Manner by Exosomes and Impacts Neuronal Survival

Emmanouilidou¹,

Melachroinou²,

Roumeliotis³

et al. 2010

J. Neurosci.

944

932

View full text Add to dashboard Cite

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“…In contrast D1 infusion does not improve cognition (van Groen et al, 2009). Similarly it has been demonstrated that Congo red (Inouye andKirschner, 2005, Lee, 2002) and thioflavine-S improve pathology (Alavez et al, 2011). Together, we have demonstrated that 1) D-peptides that specifically bind to A 42 and, 2) that the D-peptides staining is similar, but more specific, to most traditional histochemical amyloid staining methods.…”

Section: Discussionmentioning

confidence: 87%

Staining of Amyloid Beta (Abeta) Using (Immuno) Histochemical Techniques and Abeta42 Specific Peptides

Groen¹,

Kadish²,

Funke³

et al. 2011

Neuroimaging for Clinicians - Combining Research and Practice

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“…The majority of assays used for inhibitor identification apply dye-binding protocols that differentiate between free dye and dye bound to peptide aggregates by measuring spectral shifts. These dyes bind to peptide aggregates by non-specific, hydrophobic interactions and are unable to discern between low-versus highmolecular weight aggregates [53][54][55][56][57][58]. This has become of concern since recent studies suggest that the early stages of peptide oligomerization forming low-molecular weight aggregates may represent the most toxic form in vivo [7,9,10,59].…”

Section: Discussionmentioning

confidence: 99%

A Sensitive Aβ Oligomerization Assay for Identification of Small Molecule Inhibitors

Gonzales¹,

Orlando²

2009

TOBIOTJ

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Amyloid deposits found in Alzheimer's disease result from aggregation of peptide which leads to loss of synaptic function, chronic microglial activation and cognitive impairment. Because of this, identification of small molecule inhibitors of aggregation as potential therapeutics is a topic of current interest. The majority of inhibitor screening approaches rely on in vitro assays that lack the necessary sensitivity to distinguish low-molecular weight oligomers from larger, more advanced-stage fibrillar structures. Differentiating between these two structures is of vital concern since recent studies indicate that small, early-stage oligomers are the most neurotoxic form of peptide aggregate. To address this limitation, we have explored the adaptability of a recently described ELISA-based assay for discovery of small molecule inhibitors of oligomerization. Results show that this assay is highly sensitive as it is able to quantify oligomers with as little as 80 nM input peptide. In addition, data were obtained re-confirming the function of curcumin as a potent inhibitor of aggregation (IC 50 = 2 μM) and defining its inhibitor:peptide functional stoichiometry. Further examination of other known anti-aggregation compounds showed that this assay is able to discriminate between inhibitors of early-stage, low-molecular weight oligomers and later-stage, high-molecular weight fibrillar structures. These findings indicate that this new ELISA-based assay is capable of identifying novel small molecule inhibitors that function during the initial stages of peptide assembly.

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Alzheimer’s β-Amyloid: Insights into Fibril Formation and Structure from Congo Red Binding

Cited by 40 publications

References 70 publications

Cell-Produced α-Synuclein Is Secreted in a Calcium-Dependent Manner by Exosomes and Impacts Neuronal Survival

Cell-Produced α-Synuclein Is Secreted in a Calcium-Dependent Manner by Exosomes and Impacts Neuronal Survival

Staining of Amyloid Beta (Abeta) Using (Immuno) Histochemical Techniques and Abeta42 Specific Peptides

A Sensitive Aβ Oligomerization Assay for Identification of Small Molecule Inhibitors

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