Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases

Bucciantini, Monica; Giannoni, Elisa; Chiti, Fabrizio; Baroni, Fabiana; Formigli, Lucia; Zurdo, Jesús; Taddei, Niccolò; Ramponi, Giampietro; Dobson, Christopher M.; Stefani, Massimo

doi:10.1038/416507a

Cited by 2,352 publications

(2,057 citation statements)

References 32 publications

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“…The different spectral features of oligomers and fibrils are used to determine the oligomeric content over aging time. This is, in our opinion, essential as the cytotoxicity was found to depend on the conformational organization of oligomers [56]. One could speculate that toxicity of oligomers may be related to their structural order, their morphologies and their ability to impair cellular processes by interacting with membranes as suggested by [6,57].…”

Section: Discussionmentioning

confidence: 87%

Transformation of amyloid β(1–40) oligomers into fibrils is characterized by a major change in secondary structure

Sarroukh

Cerf

Derclaye

et al. 2010

Cell. Mol. Life Sci.

136

119

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Alzheimer's disease (AD) is a neurodegenerative disorder occurring in the elderly. It is widely accepted that the amyloid beta peptide (Ab) aggregation and especially the oligomeric states rather than fibrils are involved in AD onset. We used infrared spectroscopy to provide structural information on the entire aggregation pathway of Ab(1-40), starting from monomeric Ab to the end of the process, fibrils. Our structural study suggests that conversion of oligomers into fibrils results from a transition from antiparallel to parallel b-sheet. These structural changes are described in terms of H-bonding rupture/formation, b-strands reorientation and b-sheet elongation. As antiparallel b-sheet structure is also observed for other amyloidogenic proteins forming oligomers, reorganization of the b-sheet implicating a reorientation of b-strands could be a generic mechanism determining the kinetics of protein misfolding. Elucidation of the process driving aggregation, including structural transitions, could be essential in a search for therapies inhibiting aggregation or disrupting aggregates.

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Section: Discussionmentioning

confidence: 87%

Transformation of amyloid β(1–40) oligomers into fibrils is characterized by a major change in secondary structure

Sarroukh

Cerf

Derclaye

et al. 2010

Cell. Mol. Life Sci.

136

119

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“…oligomers and protofibrils) are toxic, rather than the mature fibrils into which they develop. 11 The demonstration that these species are, in addition to being highly cytotoxic, readily diffusible throughout the brain may explain why neuronal loss is commonly observed at sites distant from those of the amyloid deposits. By proposing that the primary toxic species are the early aggregates, this theory also provides a plausible explanation for the lack of correlation between the extent of deposition of mature fibrils in the form of amyloid plaques in the diseased brain and the severity of clinical symptoms.…”

Section: Causes Of Amyloid Pathologymentioning

confidence: 99%

“…3 These protofibrils have been shown to be more toxic than both the protein/peptide from which they are made and mature fibrils constructed from them. 11 If this scenario is correct, then it follows that at least under some conditions EC-mediated inhibition of protein aggregation could actually promote cytotoxicity. When tested against neuronal cell lines, under certain specific conditions, clusterin and  2 M were shown to promote the neurotoxicity of A (clusterin -PC12 cells; 104  2 M -LAN5 cells 57 ).…”

Section: The In Vitro Effects Of Ecs On Amyloid Toxicitymentioning

confidence: 99%

Potential roles of abundant extracellular chaperones in the control of amyloid formation and toxicity

2008

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The in vivo formation of fibrillar proteinaceous deposits called amyloid is associated with more than 40 serious human diseases, collectively referred to as protein deposition diseases. In many cases the amyloid deposits are extracellular and are found associated with newly identified abundant extracellular chaperones (ECs). Evidence is presented suggesting an important regulatory role for ECs in amyloid formation and disposal in the body. A model is presented which proposes that, under normal conditions, ECs stabilize extracellular misfolded proteins by binding to them, and then guide them to specific cell receptors for uptake and subsequent degradation. Thus ECs and their receptors may be critical parts of a quality control system to protect the body against dangerously hydrophobic proteins/peptides. However, it also appears possible that in the presence of a high molar excess of misfolded protein, such as might occur during disease, the limited amounts of ECs available may actually exacebate pathology. Further advances in understanding of the mechanisms that control extracellular protein folding are likely to identify new strategies for effective disease therapies. Keywords: Extracellular chaperones, receptor-mediated endocytosis, amyloid, protein quality control, aggregate toxicity, fibril formation word statement (for Contents list) plus graphic (note -colour version of below graphic provided separately)Newly identified abundant extracellular chaperones (ECs) may protect the body against dangerously hydrophobic proteins/peptides. This review proposes that ECs stabilize extracellular misfolded proteins by binding to them, and then guide them to specific receptors for uptake and subsequent degradation. SUMMARYThe in vivo formation of fibrillar proteinaceous deposits called amyloid is associated with more than 40 serious human diseases, collectively referred to as protein deposition diseases. In many cases the amyloid deposits are extracellular and are found associated with newly identified abundant extracellular chaperones (ECs). Evidence is presented suggesting an important regulatory role for ECs in amyloid formation and disposal in the body. A model is presented which proposes that, under normal conditions, ECs stabilize extracellular misfolded proteins by binding to them, and then guide them to specific cell receptors for uptake and subsequent degradation. Thus ECs and their receptors may be critical parts of a quality control system to protect the body against dangerously hydrophobic proteins/peptides. However, it also appears possible that in the presence of a high molar excess of misfolded protein, such as might occur during disease, the limited amounts of ECs available may actually exacebate pathology. Further advances in understanding of the mechanisms that control extracellular protein folding are likely to identify new strategies for effective disease therapies.

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“…Aggregates are neurotoxic (or more generally cytotoxic) in at least some forms (Bucciantini et al ., 2002); it remains unresolved whether the greater threat is posed by relatively soluble and diffuse aggregates (typically oligomeric) or insoluble, compact conglomerates (Tai et al ., 2013). Protein aggregates have been shown to form even during normal aging of nematodes (David et al ., 2010; Ayyadevara et al ., 2014).…”

Section: Introductionmentioning

confidence: 99%

Proteins that mediate protein aggregation and cytotoxicity distinguish Alzheimer's hippocampus from normal controls

et al. 2016

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SummaryNeurodegenerative diseases are distinguished by characteristic protein aggregates initiated by disease‐specific ‘seed’ proteins; however, roles of other co‐aggregated proteins remain largely unexplored. Compact hippocampal aggregates were purified from Alzheimer's and control‐subject pools using magnetic‐bead immunoaffinity pulldowns. Their components were fractionated by electrophoretic mobility and analyzed by high‐resolution proteomics. Although total detergent‐insoluble aggregates from Alzheimer's and controls had similar protein content, within the fractions isolated by tau or Aβ1–42 pulldown, the protein constituents of Alzheimer‐derived aggregates were more abundant, diverse, and post‐translationally modified than those from controls. Tau‐ and Aβ‐containing aggregates were distinguished by multiple components, and yet shared >90% of their protein constituents, implying similar accretion mechanisms. Alzheimer‐specific protein enrichment in tau‐containing aggregates was corroborated for individuals by three analyses. Five proteins inferred to co‐aggregate with tau were confirmed by precise in situ methods, including proximity ligation amplification that requires co‐localization within 40 nm. Nematode orthologs of 21 proteins, which showed Alzheimer‐specific enrichment in tau‐containing aggregates, were assessed for aggregation‐promoting roles in C. elegans by RNA‐interference ‘knockdown’. Fifteen knockdowns (71%) rescued paralysis of worms expressing muscle Aβ, and 12 (57%) rescued chemotaxis disrupted by neuronal Aβ expression. Proteins identified in compact human aggregates, bound by antibody to total tau, were thus shown to play causal roles in aggregation based on nematode models triggered by Aβ1–42. These observations imply shared mechanisms driving both types of aggregation, and/or aggregate‐mediated cross‐talk between tau and Aβ. Knowledge of protein components that promote protein accrual in diverse aggregate types implicates common mechanisms and identifies novel targets for drug intervention.

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Inherent toxicity of aggregates implies a common mechanism for protein misfolding diseases

Cited by 2,352 publications

References 32 publications

Transformation of amyloid β(1–40) oligomers into fibrils is characterized by a major change in secondary structure

Transformation of amyloid β(1–40) oligomers into fibrils is characterized by a major change in secondary structure

Potential roles of abundant extracellular chaperones in the control of amyloid formation and toxicity

Proteins that mediate protein aggregation and cytotoxicity distinguish Alzheimer's hippocampus from normal controls

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