scholarly journals Amyloid Oligomer Neurotoxicity, Calcium Dysregulation, and Lipid Rafts

2011 ◽  
Vol 2011 ◽  
pp. 1-17 ◽  
Author(s):  
Fiorella Malchiodi-Albedi ◽  
Silvia Paradisi ◽  
Andrea Matteucci ◽  
Claudio Frank ◽  
Marco Diociaiuti
Keyword(s):  
Lipid Rafts ◽  
Protein Misfolding ◽  
Large Body ◽  
Amyloid Β ◽  
Misfolded Proteins ◽  
Transmissible Spongiform Encephalopathies ◽  
Amyloid Proteins ◽  
Spongiform Encephalopathies ◽  
Amyloidogenic Processing ◽  
High Propensity

Amyloid proteins constitute a chemically heterogeneous group of proteins, which share some biophysical and biological characteristics, the principal of which are the high propensity to acquire an incorrect folding and the tendency to aggregate. A number of diseases are associated with misfolding and aggregation of proteins, although only in some of them—most notably Alzheimer's disease (AD) and transmissible spongiform encephalopathies (TSEs)—a pathogenetic link with misfolded proteins is now widely recognized. Lipid rafts (LRs) have been involved in the pathophysiology of diseases associated with protein misfolding at several levels, including aggregation of misfolded proteins, amyloidogenic processing, and neurotoxicity. Among the pathogenic misfolded proteins, the AD-related protein amyloid β (Aβ) is by far the most studied protein, and a large body of evidence has been gathered on the role played by LRs in Aβ pathogenicity. However, significant amount of data has also been collected for several other amyloid proteins, so that their ability to interact with LRs can be considered an additional, shared feature characterizing the amyloid protein family. In this paper, we will review the evidence on the role of LRs in the neurotoxicity of huntingtin, α-synuclein, prion protein, and calcitonin.

Metal-dependent generation of reactive oxygen species from amyloid proteins implicated in neurodegenerative disease

2008 ◽  
Vol 36 (6) ◽  
pp. 1293-1298 ◽  
Author(s):  
David Allsop ◽  
Jennifer Mayes ◽  
Susan Moore ◽  
Atef Masad ◽  
Brian J. Tabner
Keyword(s):  
Protein Misfolding ◽  
Cultured Cells ◽  
Amyloid Β ◽  
Transition Metal Ions ◽  
Transmissible Spongiform Encephalopathies ◽  
Amyloid Β Peptide ◽  
Spongiform Encephalopathies ◽  
Fenton Chemistry ◽  
Redox Active ◽  
Aβ Amyloid

Using a method based on ESR spectroscopy and spin-trapping, we have shown that Aβ (amyloid β-peptide) (implicated in Alzheimer's disease), α-synuclein (implicated in Parkinson's disease), ABri (British dementia peptide) (responsible for familial British dementia), certain toxic fragments of the prion protein (implicated in the transmissible spongiform encephalopathies) and the amylin peptide (found in the pancreas in Type 2 diabetes mellitus) all have the common ability to generate H2O2in vitro. Numerous controls (reverse, scrambled and non-toxic peptides) lacked this property. We have also noted a positive correlation between the ability of the various proteins tested to generate H2O2 and their toxic effects on cultured cells. In the case of Aβ and ABri, we have shown that H2O2 is generated as a short burst during the early stages of aggregation and is associated with the presence of protofibrils or oligomers, rather than mature fibrils. H2O2 is readily converted into the aggressive hydroxyl radical by Fenton chemistry, and this extremely reactive radical could be responsible for much of the oxidative damage seen in all of the above disorders. We suggest that the formation of a redox-active complex involving the relevant amyloidogenic protein and certain transition-metal ions could play an important role in the pathogenesis of several different protein misfolding disorders.

In Vitro Conversion Assays Diagnostic for Neurodegenerative Proteinopathies

2019 ◽  
Vol 5 (1) ◽  
pp. 142-157 ◽  
Author(s):  
Serena Singh ◽  
Mari L DeMarco
Keyword(s):  
Prion Protein ◽  
Protein Misfolding ◽  
Amyloid Β ◽  
Intrinsic Property ◽  
Transmissible Spongiform Encephalopathies ◽  
Diagnostic Tools ◽  
Clinical Implementation ◽  
Spongiform Encephalopathies ◽  
Further Development

Abstract Background In vitro conversion assays, including real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA) techniques, were first developed to study the conversion process of the prion protein to its misfolded, disease-associated conformation. The intrinsic property of prion proteins to propagate their misfolded structure was later exploited to detect subfemtogram quantities of the misfolded protein present in tissues and fluids from humans and animals with transmissible spongiform encephalopathies. Currently, conversion assays are used clinically as sensitive and specific diagnostic tools for antemortem diagnosis of prion disease. Content In vitro conversion assays are now being applied to the development of diagnostics for related neurodegenerative diseases, including detection of misfolded α-synuclein in Parkinson disease, misfolded amyloid-β in Alzheimer disease, and misfolded tau in Pick disease. Like the predicate prion protein in vitro conversion diagnostics, these assays exploit the ability of endogenously misfolded proteins to induce misfolding and aggregation of their natively folded counterpart in vitro. This property enables biomarker detection of the underlying protein pathology. Herein, we review RT-QuIC and PMCA for (a) prion-, (b) α-synuclein-, (c) amyloid-β-, and (d) tau-opathies. Summary Although already in routine clinical use for the detection of transmissible spongiform encephalopathies, in vitro conversion assays for other neurodegenerative disorders require further development and evaluation of diagnostic performance before consideration for clinical implementation.

scholarly journals Classical BSE prions emerge from asymptomatic pigs challenged with atypical/Nor98 scrapie

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Belén Marín ◽  
Alicia Otero ◽  
Séverine Lugan ◽  
Juan Carlos Espinosa ◽  
Alba Marín-Moreno ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Clinical Signs ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Post Inoculation ◽  
Atypical Scrapie ◽  
Wasting Disease ◽  
Spongiform Encephalopathies ◽  
Robust Transmission

AbstractPigs are susceptible to infection with the classical bovine spongiform encephalopathy (C-BSE) agent following experimental inoculation, and PrPSc accumulation was detected in porcine tissues after the inoculation of certain scrapie and chronic wasting disease isolates. However, a robust transmission barrier has been described in this species and, although they were exposed to C-BSE agent in many European countries, no cases of natural transmissible spongiform encephalopathies (TSE) infections have been reported in pigs. Transmission of atypical scrapie to bovinized mice resulted in the emergence of C-BSE prions. Here, we conducted a study to determine if pigs are susceptible to atypical scrapie. To this end, 12, 8–9-month-old minipigs were intracerebrally inoculated with two atypical scrapie sources. Animals were euthanized between 22- and 72-months post inoculation without clinical signs of TSE. All pigs tested negative for PrPSc accumulation by enzyme immunoassay, immunohistochemistry, western blotting and bioassay in porcine PrP mice. Surprisingly, in vitro protein misfolding cyclic amplification demonstrated the presence of C-BSE prions in different brain areas from seven pigs inoculated with both atypical scrapie isolates. Our results suggest that pigs exposed to atypical scrapie prions could become a reservoir for C-BSE and corroborate that C-BSE prions emerge during interspecies passage of atypical scrapie.

scholarly journals Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 469
Author(s):  
Hasier Eraña ◽  
Jorge M. Charco ◽  
Ezequiel González-Miranda ◽  
Sandra García-Martínez ◽  
Rafael López-Moreno ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Prion Diseases ◽  
Immunohistochemical Analysis ◽  
Body Fluids ◽  
Detection Methods ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Prion Propagation

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrPSc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrPSc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrPSc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.

scholarly journals Amyloidogenic Processing of APP in Lipid Rafts

2010 ◽  
Vol 3 (1) ◽  
pp. 21-31
Author(s):  
Madepalli K. Lakshmana ◽  
Subhojit Roy ◽  
Kaihong Mi ◽  
David E. Kang
Keyword(s):  
Lipid Rafts ◽  
Lipid Raft ◽  
Amyloid Β ◽  
Convincing Evidence ◽  
Amyloid Β Peptide ◽  
Cholesterol Levels ◽  
Amyloidogenic Processing ◽  
Secretase Inhibitor ◽  
Aβ Generation ◽  
Lipid Raft Microdomains

Increased generation of amyloid β peptide (Aβ) derived from amyloid precursor protein (APP) is the primary pathological characteristic of Alzheimer’s disease (AD). However, the sub cellular compartment in which APP undergoes cleavage by secretases to generate Aβ is not precisely known. Compelling evidences suggest that amyloidogenic processing of APP occurs in lipid rafts. An indirect support for lipid raft processing of APP includes the localization of Aβ, APP C-terminal fragments (CTFs), APP holoprotein and secretases in the lipid raft microdomains, although few studies failed to find APP in the lipid rafts. The indirect support also comes from both experimental and clinical studies involving modulation of cholesterol levels and its effect on Aβ generation. Moderate depletion of cholesterol results in significant reduction in Aβ levels and increased dietary intake of cholesterol leads to higher levels of Aβ production suggesting that amyloidogenic processing of APP strongly depends on cholesterol levels and therefore on lipid raft integrity. More convincing evidence that lipid rafts are critical for amyloidogenic processing of APP comes from studies using antibody-mediated co-patching of APP and BACE1 which results in lipid raft association of APP and BACE1 and increased Aβ generation. Further, an endosome/lipid raft targeting of β-secretase inhibitor by sterol-mediated anchoring leading to reduced Aβ generation also suggests that lipid rafts are pivotal for amyloidogenic processing of APP. In the absence of an effective therapy for AD, proteins responsible for delivery of APP to lipid rafts including LRP, RanBP9 and ApoER2 may be excellent therapeutic targets in AD.

scholarly journals Complex proteinopathies and neurodegeneration: insights from the study of transmissible spongiform encephalopathies

2018 ◽  
Vol 76 (10) ◽  
pp. 705-712
Author(s):  
Pedro Piccardo ◽  
David M. Asher
Keyword(s):  
Protein Misfolding ◽  
Wide Spectrum ◽  
Prion Diseases ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathies ◽  
Duration Of Illness ◽  
Secondary Result ◽  
Different Strains ◽  
New Treatments ◽  
Misfolding Diseases

ABSTRACT Protein misfolding diseases are usually associated with deposits of single “key” proteins that somehow drive the pathology; β-amyloid and hyperphosphorylated tau accumulate in Alzheimer's disease, α-synuclein in Parkinson's disease, or abnormal prion protein (PrPTSE) in transmissible spongiform encephalopathies (TSEs or prion diseases). However, in some diseases more than two proteins accumulate in the same brain. These diseases might be considered “complex” proteinopathies. We have studied models of TSEs (to explore deposits of PrPTSE and of “secondary proteins”) infecting different strains and doses of TSE agent, factors that control incubation period, duration of illness and histopathology. Model TSEs allowed us to investigate whether different features of histopathology are independent of PrPTSE or appear as a secondary result of PrPTSE. Better understanding the complex proteinopathies may help to explain the wide spectrum of degenerative diseases and why some overlap clinically and histopathologically. These studies might also improve diagnosis and eventually even suggest new treatments for human neurodegenerative diseases.

scholarly journals Extracellular Amyloid Deposits in Alzheimer’s and Creutzfeldt–Jakob Disease: Similar Behavior of Different Proteins?

2020 ◽  
Vol 22 (1) ◽  
pp. 7
Author(s):  
Nikol Jankovska ◽  
Tomas Olejar ◽  
Radoslav Matej
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Specific Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Amyloid Β Protein ◽  
Spongiform Encephalopathies ◽  
Systematic Classification ◽  
Amyloid Deposits ◽  
Jakob Disease

Neurodegenerative diseases are characterized by the deposition of specific protein aggregates, both intracellularly and/or extracellularly, depending on the type of disease. The extracellular occurrence of tridimensional structures formed by amyloidogenic proteins defines Alzheimer’s disease, in which plaques are composed of amyloid β-protein, while in prionoses, the same term “amyloid” refers to the amyloid prion protein. In this review, we focused on providing a detailed didactic description and differentiation of diffuse, neuritic, and burnt-out plaques found in Alzheimer’s disease and kuru-like, florid, multicentric, and neuritic plaques in human transmissible spongiform encephalopathies, followed by a systematic classification of the morphological similarities and differences between the extracellular amyloid deposits in these disorders. Both conditions are accompanied by the extracellular deposits that share certain signs, including neuritic degeneration, suggesting a particular role for amyloid protein toxicity.

scholarly journals Cerebrospinal Fluid and Plasma Small Extracellular Vesicles and miRNAs as Biomarkers for Prion Diseases

2021 ◽  
Vol 22 (13) ◽  
pp. 6822
Author(s):  
Óscar López-Pérez ◽  
David Sanz-Rubio ◽  
Adelaida Hernaiz ◽  
Marina Betancor ◽  
Alicia Otero ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Protein Misfolding ◽  
Prion Diseases ◽  
Clinical Stage ◽  
Proteinase K ◽  
Transmissible Spongiform Encephalopathies ◽  
Alternative Source ◽  
Spongiform Encephalopathies ◽  
In Vivo Diagnosis

Diagnosis of transmissible spongiform encephalopathies (TSEs), or prion diseases, is based on the detection of proteinase K (PK)-resistant PrPSc in post-mortem tissues as indication of infection and disease. Since PrPSc detection is not considered a reliable method for in vivo diagnosis in most TSEs, it is of crucial importance to identify an alternative source of biomarkers to provide useful alternatives for current diagnostic methodology. Ovine scrapie is the prototype of TSEs and has been known for a long time. Using this natural model of TSE, we investigated the presence of PrPSc in exosomes derived from plasma and cerebrospinal fluid (CSF) by protein misfolding cyclic amplification (PMCA) and the levels of candidate microRNAs (miRNAs) by quantitative PCR (qPCR). Significant scrapie-associated increase was found for miR-21-5p in plasma-derived but not in CSF-derived exosomes. However, miR-342-3p, miR-146a-5p, miR-128-3p and miR-21-5p displayed higher levels in total CSF from scrapie-infected sheep. The analysis of overexpressed miRNAs in this biofluid, together with plasma exosomal miR-21-5p, could help in scrapie diagnosis once the presence of the disease is suspected. In addition, we found the presence of PrPSc in most CSF-derived exosomes from clinically affected sheep, which may facilitate in vivo diagnosis of prion diseases, at least during the clinical stage.

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