Time resolved structure analysis of growing β-amyloid fibers

Witte, Thomas; Haller, Lars A.; Luttmann, Edgar; Krüger, Jens; Fels, Gregor; Huber, Klaus

doi:10.1016/j.jsb.2007.02.006

Cited by 14 publications

(18 citation statements)

References 52 publications

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“…In amyloidosis, physical properties like the pitch size and stiffness of amyloid fibrils evolve over time to yield increased fibrillar stiffness. [ 50–52 ] Indeed, FapCS derived from younger FapC fibrils (fibrillated for 4 d at 37 °C and 25 °C) accelerated A β fibrillization (Figure S3, Supporting Information), but less than the seeds derived from mature FapC fibrils (fibrillated for 7 d at 37 °C) (Figure 1A). This age dependence can be explained by the brittle nature of mature fibrils, [ 53 ] or simply by the greater population of mature fibrils to yield more seeds.…”

Section: Resultsmentioning

confidence: 99%

Accelerated Amyloid Beta Pathogenesis by Bacterial Amyloid FapC

et al. 2020

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The gut–brain axis has attracted increasing attention in recent years, fueled by accumulating symptomatic, physiological, and pathological findings. In this study, the aggregation and toxicity of amyloid beta (Aβ), the pathogenic peptide associated with Alzheimer's disease (AD), seeded by FapC amyloid fragments (FapCS) of Pseudomonas aeruginosa that colonizes the gut microbiome through infections are examined. FapCS display favorable binding with Aβ and a catalytic capacity in seeding the peptide amyloidosis. Upon seeding, twisted Aβ fibrils assume a much‐shortened periodicity approximating that of FapC fibrils, accompanied by a 37% sharp rise in the fibrillar diameter, compared with the control. The robust seeding capacity for Aβ by FapCS and the biofilm fragments derived from P. aeruginosa entail abnormal behavior pathology and immunohistology, as well as impaired cognitive function of zebrafish. Together, the data offer the first concrete evidence of structural integration and inheritance in peptide cross‐seeding, a crucial knowledge gap in understanding the pathological correlations between different amyloid diseases. The catalytic role of infectious bacteria in promoting Aβ amyloidosis may be exploited as a potential therapeutic target, while the altered mesoscopic signatures of Aβ fibrils may serve as a prototype for molecular assembly and a biomarker for screening bacterial infections in AD.

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Section: Resultsmentioning

confidence: 99%

Accelerated Amyloid Beta Pathogenesis by Bacterial Amyloid FapC

et al. 2020

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“…Hence, the approach supports the combination of the wormlike chain model with the INE model in order to describe the dye aggregation under consideration. The second route was already pursued in our earlier works 6,7,11 and consists in the evaluation of the weightaveraged contour length L w by means of eq 33. The resulting values of L w like R g remain unaffected by the unbound monomers because the effect of the total concentration including monomers and aggregates cancels in the product c· M w .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Kinetic and Structural Features of a Dyestuff Coaggregation Studied by Time-Resolved Static Light Scattering

et al. 2013

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A binary dyestuff aggregate with a distinct stoichiometry is formed in dilute aqueous solution upon addition of Mg(2+) ions. The aggregation process was investigated with time-resolved multiangle static light scattering resulting in a sequence of static scattering curves. The scattering curves were analyzed with respect to the aggregation kinetics as well as the structure of the growing aggregates. The aggregation kinetics was based on the time evolution of the weight-averaged molar mass values extracted from the intercepts of the static scattering curves. A kinetic model that considers solely a nucleation step and monomer addition in its most simple form was developed in order to describe the evolution of time-dependent mass data. In addition, a kinetic model introduced by Lomakin et al. (Proc. Natl. Acad. Sci. U.S.A. 1996, 93, 1125) for the description of β-amyloid aggregation was adapted to the same experimental data. Application of the two kinetic models offered significant information on the role of magnesium ions within the aggregation process and provided a deeper understanding of the aggregation mechanism. Correlation of the size parameters extracted from the initial slopes of the scattering curves with the respective mass data as well as direct fitting of the scattering curves with the wormlike chain model yield a consistent set of model parameters.

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“…This can at least in part be attributed to the large variety of proteins showing self‐assembly and to the broad range of cosolutes including species as diverse as polymeric chains, compact proteins and smaller molecules of variable size and chemical nature. In order to make one step forward in classification of crowders, a few representative proteins like human islet amyloid polypeptide (IAPP), MET16, and Ab may be selected to be exposed systematically to different crowding agents. It is at this point where we would like to stress an analogy between proteins and synthetic dyestuffs as this analogy serves as an alternative starting point .…”

Section: Introductionmentioning

confidence: 99%

Self‐Assembly of Pseudo‐Isocyanine Chloride as a Sensor for Macromolecular Crowding In Vitro and In Vivo

Hämisch

Pollak

Ebbinghaus

et al. 2020

Chemistry A European J

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Pseudo-isocyanine chloride (PIC) is ac ationic dyestuff that exhibits self-assembly in aqueous solution, promoted either by increasing the PIC concentration or by decreasing the temperature. PIC-aggregates exhibit ac haracteristic and sharp absorption band as wella saf luorescence band at aw avelength of 573 nm making PIC an interesting candidate to analyze the self-assembly process in variousenvironments. The presentw ork developed PIC-based, synthetic model systems, suitablet oi nvestigate how macromolecular crowding influences self-assembly processes. Four synthetic additives were used as potentialc rowders:T riethylene glycol (TEG), polyethylene glycol (PEG), Ficoll 400 as ah ighly branched polysaccharide, and sucrose corresponding to the monomericu nit of Ficoll. Combined UV/Vis spectroscopy and time-resolved light scattering revealed as trong impact of crowding based on excludedv olume effects only for Ficoll 400. Sucrose had hardly any influence on the self-assembly of PIC and PEG and TEG impeded the PIC self-assembly.D evelopment of such aP IC based models ystem led over to in-cell experiments.H eLa cells were infiltrated with PIC solutionswell below the aggregation threshold in the infiltrating solution. In the cellular environment, PIC was exposed to as ignificant crowding andi mmediatelys tarted to aggregate. As was demonstrated by fluorescencei maging, the extent of aggregation can be modulated by exposing the cells to salt-induced osmotic stress. The resultss uggest future use of such as ystem as as ensor for the analysis of in vitro and in vivo crowding effects on self-assembly processes. Sample preparationAqueous solutions of crowding agents with contents varying from 2wt% to 25 wt %s erved as solvents. Solvents containing Ficoll 400 were slightly acidic. As Ficoll would undergo chemical decomposition, especially at elevated temperatures, the pH of the solvent thus had to be adjusted to 7t oe nsure chemical stability of Ficoll 400. Stock solutions of PIC in the presence of crowding agents had

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Time resolved structure analysis of growing β-amyloid fibers

Cited by 14 publications

References 52 publications

Accelerated Amyloid Beta Pathogenesis by Bacterial Amyloid FapC

Accelerated Amyloid Beta Pathogenesis by Bacterial Amyloid FapC

Kinetic and Structural Features of a Dyestuff Coaggregation Studied by Time-Resolved Static Light Scattering

Self‐Assembly of Pseudo‐Isocyanine Chloride as a Sensor for Macromolecular Crowding In Vitro and In Vivo

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