Transthyretin forms amyloid fibrils at physiological pH with ultrasonication

Misumi, Yohei; Ueda, Mitsuharu; Fujimori, Hiroaki; Shinriki, Satoru; Meng, Wei; Kim, Jaemi; Saito, Shiori; Obayashi, Konen; Uchino, Makoto; Ando, Yumiko

doi:10.1080/13506120802524684

Cited by 8 publications

(6 citation statements)

References 22 publications

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“…CD accordingly revealed a considerably rearranged structure of protofibrils compared to native TTR ( Fig. 8B ), as also observed using different fibrillation protocols 24 51 80 . The TTR crystal structure contains 5% α-helix, 48% β-sheet and 47% turns and disordered components.…”

Section: Figuresupporting

confidence: 74%

Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils

Groenning

Campos

Hirschberg

et al. 2015

Sci Rep

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Despite numerous studies, a detailed description of the transthyretin (TTR) self-assembly mechanism and fibril structure in TTR amyloidoses remains unresolved. Here, using a combination of primarily small -angle X-ray scattering (SAXS) and hydrogen exchange mass spectrometry (HXMS) analysis, we describe an unexpectedly dynamic TTR protofibril structure which exchanges protomers with highly unfolded monomers in solution. The protofibrils only grow to an approximate final size of 2,900 kDa and a length of 70 nm and a comparative HXMS analysis of native and aggregated samples revealed a much higher average solvent exposure of TTR upon fibrillation. With SAXS, we reveal the continuous presence of a considerably unfolded TTR monomer throughout the fibrillation process, and show that a considerable fraction of the fibrillating protein remains in solution even at a late maturation state. Together, these data reveal that the fibrillar state interchanges with the solution state. Accordingly, we suggest that TTR fibrillation proceeds via addition of considerably unfolded monomers, and the continuous presence of amyloidogenic structures near the protofibril surface offers a plausible explanation for secondary nucleation. We argue that the presence of such dynamic structural equilibria must impact future therapeutic development strategies.

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Section: Figuresupporting

confidence: 74%

Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils

Groenning

Campos

Hirschberg

et al. 2015

Sci Rep

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“…The propensity of TTR under mildly acidic conditions (pH 3.5 to 5) to adopt aggregation has been reviewed in detail. , In spite of an acidic pH, the importance of an aggregation-prone unfolded state that emerges through various denaturing conditions has been emphasized as well. For instance, TTR conformational changes favoring the aggregation under chemical, high pressure, and thermal denaturation, , and also ultrasonication have been reported. Accordingly, we have characterized two distinct aggregation pathways for mTTR, taking advantage of various biophysical assays.…”

Section: Resultsmentioning

confidence: 99%

Inhibiting mTTR Aggregation/Fibrillation by a Chaperone-like Hydrophobic Amino Acid-Conjugated SPION

et al. 2022

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Transthyretin (TTR) aggregation via misfolding of a mutant or wild-type protein leads to systemic or partial amyloidosis (ATTR). Here, we utilized variable biophysical assays to characterize two distinct aggregation pathways for mTTR (a synthesized monomer TTR incapable of association into a tetramer) at pH 4.3 and also pH 7.4 with agitation, referred to as mTTR aggregation and fibrillation, respectively. The findings suggest that early-stage conformational changes termed monomer activation here determine the aggregation pathway, resulting in developing either amorphous aggregates or well-organized fibrils. Less packed partially unfolded monomers consisting of more nonregular secondary structures that were rapidly produced via a mildly acidic condition form amorphous aggregates. Meanwhile, more hydrophobic and packed monomers consisting of rearranged β sheets and increased helical content developed well-organized fibrils. Conjugating superparamagnetic iron oxide nanoparticles (SPIONs) with leucine and glutamine (L-SPIONs and G-SPIONs in order) via a trimethoxysilane linker provided the chance to study the effect of hydrophobic/hydrophilic surfaces on mTTR aggregation. The results indicated a powerful inhibitory effect of hydrophobic L-SPIONs on both mTTR aggregation and fibrillation. Monomer depletion was introduced as the governing mechanism for inhibiting mTTR aggregation, while a chaperone-like property of L-SPIONs by maintaining an mTTR native structure and adsorbing oligomers suppressed the progression of further fibril formation.

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“…Stathopulos et al 34) showed that ultrasonication results in the formation of amyloid-like aggregates. Subsequently, amyloid fibrillation of various proteins such as -synuclein, 52) 2-m, 53) transthyretin, 54) and mouse prion proteins 50) was reported to be accelerated by ultrasonic irradiation. Under certain conditions, aggregation of amyloid peptide is also promoted by ultrasonication.…”

Section: Mechanism Of Ultrasonication-triggered Fibrillation and Futumentioning

confidence: 99%

Ultrasonication: An Efficient Agitation for Accelerating the Supersaturation-Limited Amyloid Fibrillation of Proteins

Yoshimura

Yagi

et al. 2013

Jpn. J. Appl. Phys.

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Amyloid fibrils are self-assemblies of proteins with an ordered cross-β architecture. Because they are associated with serious disorders, understanding their structure and mechanism of fibrillation is important. Irradiation with ultrasonication leads to fragmentation of amyloid fibrils, useful for seeding experiments. Recently, ultrasonication has been found to trigger the spontaneous formation of fibrils in solutions of monomeric amyloidogenic proteins. The results indicate that amyloid fibrillation is similar to the crystallization of solutes from a supersaturated solution. The accelerating effects of ultrasonication on amyloid fibrillation suggest that cavitation microbubbles play a key role in effectively converting the metastable state of supersaturation to the labile state, leading to spontaneous fibrillation. Moreover, ultrasonic irradiation would be promising for a high-throughput screening assay of amyloid fibrillation, advancing the study of supersaturation-limited amyloidogenesis.

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Transthyretin forms amyloid fibrils at physiological pH with ultrasonication

Cited by 8 publications

References 22 publications

Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils

Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils

Inhibiting mTTR Aggregation/Fibrillation by a Chaperone-like Hydrophobic Amino Acid-Conjugated SPION

Ultrasonication: An Efficient Agitation for Accelerating the Supersaturation-Limited Amyloid Fibrillation of Proteins

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