Thioflavine-T and Congo Red Reveal the Polymorphism of Insulin Amyloid Fibrils When Probed by Polarization-Resolved Fluorescence Microscopy

Duboisset, Julien; Ferrand, Patrick; He, Wei; Wang, Xiao; Rigneault, Hervé; Brasselet, Sophie

doi:10.1021/jp309528f

Cited by 43 publications

(43 citation statements)

References 34 publications

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“…Rigid intercalation causes longer fluorescence lifetimes and a larger fluorescence quantum yield due to a reduction of radiationless processes (hindered rotation) in the excited state . This in fact makes the ThT a powerful molecular sensor for amyloid fibril formation in time‐resolved experiments …”

Section: Resultsmentioning

confidence: 99%

Structure‐Making Effects of Metal Nanoparticles in Amyloid Peptide Fibrillation

Gladytz

Wagner

Häupl³

et al. 2014

Part & Part Syst Charact

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There is growing concern that nanoparticles (NPs) may accelerate amyloid protein aggregation and thus cause amyloid-related diseases. Here, the potential of silver and gold NPs is explored (diameter 20 nm) on the aggregation of the amyloid peptide sequences NNFGAIL from human islet amyloid polypeptide and the yeast prion protein sequence GNNQQNY, which are both the sequences of the full systems, which are able to aggregate into characteristic amyloid cross-beta sheet fi brillar structures. Here, it is shown that silver and gold NPs in physiological aqueous solution at ambient temperatures accelerate the aggregation kinetics of both peptides signifi cantly (in vitro). Scanning electron microscopy and X-ray diffraction provide solid evidence for a "structure-making" effect of the NPs. In particular, we are able to image the initial peptide corona and measure its structural reorganization in timeresolved kinetic experiments. After a conversion time Δ t , the coated NPs appear to act as templates or seeds for rapid fi brillation. Interestingly, crossfi brillation experiments with different peptide-coated NPs (pcNPs) reveal that they can effi ciently induce aggregation of similar peptides once the pcNPs are structurally converted. It is discussed that these structurally converted pcNPs may display similar kinetic features as toxic and aggregation inducing oligomers/protofi brils in normal amyloid aggregation, without being transient and very low-concentration species. Finally, we suggest and discuss a simple mechanistic picture with the biomolecule corona of NPs being central to the function of the coated NPs in amyloid fi brillation.

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Section: Resultsmentioning

confidence: 99%

Structure‐Making Effects of Metal Nanoparticles in Amyloid Peptide Fibrillation

Gladytz

Wagner

Häupl³

et al. 2014

Part & Part Syst Charact

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“…A wall in which the average microfibril angle is transverse, but in which there is a large variation in angles in both directions away from transverse, will give less difference between the parallel and perpendicular excitations. This effect, previously observed for Congo red and thioflavin T fluorescence from amyloid fibrils (Duboisset et al ., ), might be used to investigate the degree of cell wall organization in plant tissues. Our observations of bacterial cellulose in which the longer, thinner cellulose bundles showed a stronger bifluorescence response than the shorter thicker bundles, match this.…”

Section: Discussionmentioning

confidence: 99%

“…Congo red has been used to stain amyloid fibrils (aggregated protein fibrils composed of β-sheets), and the 'apple-green birefringence' that it generates with polarized light microscopy is considered diagnostic for amyloid fibres (Howie et al, 2008). Thus, Congo red bifluorescence, as well as bifluorescence from another amyloid-staining dye thioflavin T, have been investigated by confocal microscopy, measuring not only fibril alignment but, significantly, the degree of protein alignment within fibrils (Duboisset et al, 2013). Green fluorescent protein (GFP) can also exhibit polarization-dependent fluorescence (Inoué et al, 2002), and this has been used in conventional wide-field fluorescence microscopy to investigate the architecture of fungal cell division (DeMay et al, 2011), whereas membrane properties and dynamics have been studied by polarized light confocal microscopy (Kress et al, 2013).…”

Section: Approaches For Improved Bifluorescence Imagingmentioning

confidence: 99%

Pontamine fast scarlet 4B bifluorescence and measurements of cellulose microfibril angles

Thomas

Idris

Collings

2017

Journal of Microscopy

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Pontamine fast scarlet 4B is a red paper and textiles dye that has recently been introduced as a fluorescent probe for plant cell walls. Pontamine exhibits bifluorescence, or fluorescence dependent on the polarization of the excitation light: Because cellulose is aligned within the cell wall, pontamine-labelled cell walls exhibit variable fluorescence as the excitation polarization is modulated. Thus, bifluorescence measurements require polarized excitation that can be directly or indirectly modulated. In our confocal microscopy observations of various cellulose samples labelled with pontamine, we modulated excitation polarization either through sample rotation or by the confocal's scanfield rotation function. This variably rotated laser polarizations on Leica confocal microscopes, but not those from other makers. Beginning with samples with directly observable microfibril orientations, such as purified bacterial cellulose, the velamen of orchid roots and the inner S2 layer of radiata pine compression wood, we demonstrate that modelling the variations in pontamine fluorescence with a sine curve can be used to measure the known microfibril angles. We then measured average local microfibril angles in radiata pine samples, and showed similar microfibril angles in compression and normal (opposite) wood. Significantly, bifluorescence measurements might also be used to understand the degree of local cellulose alignment within the cell wall, as opposed to variations in the overall cellulose angle.

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“…The process is promoted by certain mutations that affect protein folding which may result in erratic structures, such as self-assembled isolable aggregates believed to lead to amyloidosis and in consequence to serious diseases [2][3][4]. One of the most common detection method for amyloids in vivo and in vitro is staining with organic dyes such as Thioflavine T and Congo Red [5]. However, those chromophores are far from being ideal, and in respect of progress in diagnostic technology, new chromophores, more effective, specific and with good photophysical properties are in demand for fibrils recognition.…”

Section: Introductionmentioning

confidence: 99%

Binuclear ruthenium(II) complexes for amyloid fibrils recognition

Hańczyc

2014

Chemical Physics

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a b s t r a c tMetal-organic compounds represent a unique class of biomarkers with promising photophysical properties useful for imaging. Here interactions of insulin fibrils with two binuclear complexes [l-(11,11 0 -bidppz)(phen) 4 Ru 2 ] 4+ (1) and [l-C4(cpdppz)(phen) 4 Ru 2 ] 4+ (2) are studied by linear dichroism (LD) and fluorescence. These ruthenium(II) compounds could provide a new generation of amyloid binding chromophores with long lived lifetimes, good luminescence quantum yields for the bound molecules and photo-stability useful in multiphoton luminescence imaging.

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Thioflavine-T and Congo Red Reveal the Polymorphism of Insulin Amyloid Fibrils When Probed by Polarization-Resolved Fluorescence Microscopy

Cited by 43 publications

References 34 publications

Structure‐Making Effects of Metal Nanoparticles in Amyloid Peptide Fibrillation

Structure‐Making Effects of Metal Nanoparticles in Amyloid Peptide Fibrillation

Pontamine fast scarlet 4B bifluorescence and measurements of cellulose microfibril angles

Binuclear ruthenium(II) complexes for amyloid fibrils recognition

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