Polymorphism of hen egg white lysozyme amyloid fibrils influences the cytotoxicity in LLC-PK1 epithelial kidney cells

Mocanu, Maria-Magdalena; Ganea, Constanţa; Šipošová, Katarína; Filippi, Alexandru; Demjen, Erna; Marek, Jozef; Bednarikova, Zuzana; Antošová, Andrea; Băran, Irina; Gažová, Zuzana

doi:10.1016/j.ijbiomac.2014.01.030

Cited by 28 publications

(29 citation statements)

References 64 publications

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“…Our findings showed that differently from many other aggregating peptides and proteins, the mature aggregates of D76N b2M displayed the most severe cytotoxic effects, in agreement with the damage induced by wild‐type b2M fibrils , whereas the aggregation intermediates, including early aggregates, commonly considered most cytotoxic, were indeed less cytotoxic. This finding, albeit unusual, is not entirely surprising since in several cases fibrils toxicity eventually culminating with necrotic cell death, as in our case, has been reported . Our toxicity results were coherent with the other investigated features of the D76N b2M pre‐fibrillar aggregates and fibrils, including their ability to interact with synthetic and biological membranes.…”

Section: Discussionsupporting

confidence: 91%

Molecular insights into cell toxicity of a novel familial amyloidogenic variant of β2‐microglobulin

Leri

Bemporad

Oropesa‐Nuñez

et al. 2016

J Cellular Molecular Medi

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The first genetic variant of β2‐microglobulin (b2M) associated with a familial form of systemic amyloidosis has been recently described. The mutated protein, carrying a substitution of Asp at position 76 with an Asn (D76N b2M), exhibits a strongly enhanced amyloidogenic tendency to aggregate with respect to the wild‐type protein. In this study, we characterized the D76N b2M aggregation path and performed an unprecedented analysis of the biochemical mechanisms underlying aggregate cytotoxicity. We showed that, contrarily to what expected from other amyloid studies, early aggregates of the mutant are not the most toxic species, despite their higher surface hydrophobicity. By modulating ganglioside GM1 content in cell membrane or synthetic lipid bilayers, we confirmed the pivotal role of this lipid as aggregate recruiter favouring their cytotoxicity. We finally observed that the aggregates bind to the cell membrane inducing an alteration of its elasticity (with possible functional unbalance and cytotoxicity) in GM1‐enriched domains only, thus establishing a link between aggregate‐membrane contact and cell damage.

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Section: Discussionsupporting

confidence: 91%

Molecular insights into cell toxicity of a novel familial amyloidogenic variant of β2‐microglobulin

Leri

Bemporad

Oropesa‐Nuñez

et al. 2016

J Cellular Molecular Medi

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“…The pH 2 fibrils are long, thin, semiflexible, and curved, while the pH 6.3 fibrils are shorter, rigid, twisted, and associate laterally (Figure 1). These results are consistent with previous studies of lysozyme fibrils made under acidic and near-neutral pH conditions (Frare et al, 2004;Krebs et al, 2004;Vernaglia et al, 2004;Mossuto et al, 2010;Mocanu et al, 2014;Sulatskaya et al, 2017).…”

Section: Polymorph Fidelity Under Different Conditionssupporting

confidence: 93%

Cross-Species and Cross-Polymorph Seeding of Lysozyme Amyloid Reveals a Dominant Polymorph

Araghi

Dee

2020

Front. Mol. Biosci.

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The ability to self-propagate is one of the most intriguing characteristics of amyloid fibrils, and is a feature of great interest both to stopping unwanted pathological amyloid, and for engineering functional amyloid as a useful nanomaterial. The sequence and structural tolerances for amyloid seeding are not well understood, particularly concerning the propagation of distinct fibril morphologies (polymorphs) across species. This study examined the seeding and cross-seeding reactions between two unique fibril polymorphs, one long and flexible (formed at pH 2) and the other short and rigid (formed at pH 6.3), of human lysozyme and hen egg-white lysozyme. Both polymorphs could cross-seed aggregation across species, but this reaction was markedly reduced under physiological conditions. For both species, the pH 6.3 fibril polymorph was dominant, seeding fibril growth with a faster growth rate constant at pH 2 than the pH 2 polymorph. Based on fibrillation kinetics and fibril morphology, we found that the pH 2 polymorph was not able to faithfully replicate itself at pH 6.3. These results show that two distinct amyloid polymorphs are both capable of heterologous seeding across two species (human and hen) of lysozyme, but that the pH 6.3 polymorph is favored, regardless of the species, likely due to a lower energy barrier, or faster configurational diffusion, to accessing this particular misfolded form. These findings contribute to our better understanding of amyloid strain propagation across species barriers.

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“…Several lines of evidence implicate amyloid oligomers as the main cytotoxic species, even though not all oligomers are cytotoxic (61,62). However, the cytotoxicity of amyloid fibrils is not surprising since it has been reported repeatedly (19)(20)(21)(22)(23). In addition, given the high complexity of the fibrillation process, and considering the overall dynamics of the assembly and disassembly of toxic amyloid species, the possibility that toxicity is displayed by different conformers should not be disregarded.…”

Section: Discussionmentioning

confidence: 99%

“…These markers have been associated with amorphous TTR aggregates that can be observed in the early stages of disease evolution (18). Nevertheless, a substantial body of experimental evidence fully demonstrates that amyloid fibrils are capable of causing cellular death in numerous situations (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29). This raises the possibility that the molecular determinants underlying aggregate cytotoxicity are not always associated with the same type of species, and that there may well be oligomers and fibrils with different structural and biophysical properties, and hence with different abilities to interact with, disassemble, permeabilize, and deregulate the cell membrane (30).…”

Section: Introductionmentioning

confidence: 99%

Biochemical and Electrophysiological Modification of Amyloid Transthyretin on Cardiomyocytes

Sartiani

Bucciantini

Spinelli

et al. 2016

Biophysical Journal

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Transthyretin (TTR) amyloidoses are familial or sporadic degenerative conditions that often feature heavy cardiac involvement. Presently, no effective pharmacological therapy for TTR amyloidoses is available, mostly due to a substantial lack of knowledge about both the molecular mechanisms of TTR aggregation in tissue and the ensuing functional and viability modifications that occur in aggregate-exposed cells. TTR amyloidoses are of particular interest regarding the relation between functional and viability impairment in aggregate-exposed excitable cells such as peripheral neurons and cardiomyocytes. In particular, the latter cells provide an opportunity to investigate in parallel the electrophysiological and biochemical modifications that take place when the cells are exposed for various lengths of time to variously aggregated wild-type TTR, a condition that characterizes senile systemic amyloidosis. In this study, we investigated biochemical and electrophysiological modifications in cardiomyocytes exposed to amyloid oligomers or fibrils of wild-type TTR or to its T4-stabilized form, which resists tetramer disassembly, misfolding, and aggregation. Amyloid TTR cytotoxicity results in mitochondrial potential modification, oxidative stress, deregulation of cytoplasmic Ca 2þ levels, and Ca 2þ cycling. The altered intracellular Ca 2þ cycling causes a prolongation of the action potential, as determined by whole-cell recordings of action potentials on isolated mouse ventricular myocytes, which may contribute to the development of cellular arrhythmias and conduction alterations often seen in patients with TTR amyloidosis. Our data add information about the biochemical, functional, and viability alterations that occur in cardiomyocytes exposed to aggregated TTR, and provide clues as to the molecular and physiological basis of heart dysfunction in sporadic senile systemic amyloidosis and familial amyloid cardiomyopathy forms of TTR amyloidoses.

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Polymorphism of hen egg white lysozyme amyloid fibrils influences the cytotoxicity in LLC-PK1 epithelial kidney cells

Cited by 28 publications

References 64 publications

Molecular insights into cell toxicity of a novel familial amyloidogenic variant of β2‐microglobulin

Molecular insights into cell toxicity of a novel familial amyloidogenic variant of β2‐microglobulin

Cross-Species and Cross-Polymorph Seeding of Lysozyme Amyloid Reveals a Dominant Polymorph

Biochemical and Electrophysiological Modification of Amyloid Transthyretin on Cardiomyocytes

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