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1.
Int J Mol Sci ; 22(6)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809196

RESUMO

Deposition of amyloid ß (Aß) fibrils in the brain is a key pathologic hallmark of Alzheimer's disease. A class of polyphenolic biflavonoids is known to have anti-amyloidogenic effects by inhibiting aggregation of Aß and promoting disaggregation of Aß fibrils. In the present study, we further sought to investigate the structural basis of the Aß disaggregating activity of biflavonoids and their interactions at the atomic level. A thioflavin T (ThT) fluorescence assay revealed that amentoflavone-type biflavonoids promote disaggregation of Aß fibrils with varying potency due to specific structural differences. The computational analysis herein provides the first atomistic details for the mechanism of Aß disaggregation by biflavonoids. Molecular docking analysis showed that biflavonoids preferentially bind to the aromatic-rich, partially ordered N-termini of Aß fibril via the π-π interactions. Moreover, docking scores correlate well with the ThT EC50 values. Molecular dynamic simulations revealed that biflavonoids decrease the content of ß-sheet in Aß fibril in a structure-dependent manner. Hydrogen bond analysis further supported that the substitution of hydroxyl groups capable of hydrogen bond formation at two positions on the biflavonoid scaffold leads to significantly disaggregation of Aß fibrils. Taken together, our data indicate that biflavonoids promote disaggregation of Aß fibrils due to their ability to disrupt the fibril structure, suggesting biflavonoids as a lead class of compounds to develop a therapeutic agent for Alzheimer's disease.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Benzotiazóis/farmacologia , Biflavonoides/farmacologia , Agregação Patológica de Proteínas/tratamento farmacológico , Doença de Alzheimer/patologia , Amiloide/antagonistas & inibidores , Amiloide/efeitos dos fármacos , Amiloide/ultraestrutura , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/ultraestrutura , Biflavonoides/química , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Humanos , Ligação de Hidrogênio/efeitos dos fármacos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia
2.
Int J Mol Sci ; 22(4)2021 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-33668611

RESUMO

The maintenance of proteome homeostasis, or proteostasis, is crucial for preserving cellular functions and for cellular adaptation to environmental challenges and changes in physiological conditions. The capacity of cells to maintain proteostasis requires precise control and coordination of protein synthesis, folding, conformational maintenance, and clearance. Thus, protein degradation by the ubiquitin-proteasome system (UPS) or the autophagy-lysosomal system plays an essential role in cellular functions. However, failure of the UPS or the autophagic process can lead to the development of various diseases (aging-associated diseases, cancer), thus both these pathways have become attractive targets in the treatment of protein conformational diseases, such as alpha 1-antitrypsin deficiency (AATD). The Z alpha 1-antitrypsin (Z-AAT) misfolded variant of the serine protease alpha 1-antitrypsin (AAT) is caused by a structural change that predisposes it to protein aggregation and dramatic accumulation in the form of inclusion bodies within liver hepatocytes. This can lead to clinically significant liver disease requiring liver transplantation in childhood or adulthood. Treatment of mice with autophagy enhancers was found to reduce hepatic Z-AAT aggregate levels and protect them from AATD hepatotoxicity. To date, liver transplantation is the only curative therapeutic option for patients with AATD-mediated liver disease. Therefore, the development and discovery of new therapeutic approaches to delay or overcome disease progression is a top priority. Herein, we review AATD-mediated liver disease and the overall process of autophagy. We highlight the role of this system in the regulation of Z-variant degradation and its implication in AATD-medicated liver disease, including some open questions that remain challenges in the field and require further elucidation. Finally, we discuss how manipulation of autophagy could provide multiple routes of therapeutic benefit in AATD-mediated liver disease.


Assuntos
Autofagia , Hepatócitos , Hepatopatias , Transplante de Fígado , Fígado , Agregação Patológica de Proteínas , alfa 1-Antitripsina , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Corpos de Inclusão/genética , Corpos de Inclusão/metabolismo , Corpos de Inclusão/patologia , Fígado/metabolismo , Fígado/patologia , Hepatopatias/metabolismo , Hepatopatias/patologia , Hepatopatias/cirurgia , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Agregação Patológica de Proteínas/cirurgia , alfa 1-Antitripsina/genética , alfa 1-Antitripsina/metabolismo , Deficiência de alfa 1-Antitripsina/genética , Deficiência de alfa 1-Antitripsina/metabolismo , Deficiência de alfa 1-Antitripsina/patologia
3.
PLoS One ; 16(1): e0241161, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33497415

RESUMO

Alpha-synuclein pre-formed fibrils (PFFs) represent a promising model system for the study of cellular processes underlying cell-to-cell transmission of alpha-synuclein proteopathic aggregates. However, the ability to differentiate the fate of internalized PFFs from those which remain in the extracellular environment remains limited due to the propensity for PFFs to adhere to the cell surface. Removal of PFFs requires repeated washing and/or specific quenching of extracellular fluorescent PFF signals. In this paper we present a new method for analyzing the fate of internalized alpha-synuclein. We inserted a tobacco etch virus (TEV) protease cleavage site between alpha-synuclein and green fluorescent protein and subjected cells to brief treatment with TEV protease after incubation with tagged PFFs. As the TEV protease is highly specific, non-toxic, and active under physiological conditions, protection from TEV cleavage can be used to distinguish internalized PFFs from those which remain attached to the cell surface. Using this experimental paradigm, downstream intracellular events can be analyzed via live or fixed cell microscopy as well as by Western blotting. We suggest that this method will be useful for understanding the fate of PFFs after endocytosis under various experimental manipulations.


Assuntos
Bioensaio , Neurônios/metabolismo , Agregação Patológica de Proteínas/metabolismo , alfa-Sinucleína/metabolismo , Animais , Linhagem Celular , Endopeptidases/genética , Endopeptidases/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , alfa-Sinucleína/genética
4.
Int J Mol Sci ; 22(2)2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33477953

RESUMO

Amyloid aggregation of human ataxin-3 (ATX3) is responsible for spinocerebellar ataxia type 3, which belongs to the class of polyglutamine neurodegenerative disorders. It is widely accepted that the formation of toxic oligomeric species is primarily involved in the onset of the disease. For this reason, to understand the mechanisms underlying toxicity, we expressed both a physiological (ATX3-Q24) and a pathological ATX3 variant (ATX3-Q55) in a simplified cellular model, Escherichia coli. It has been observed that ATX3-Q55 expression induces a higher reduction of the cell growth compared to ATX3-Q24, due to the bacteriostatic effect of the toxic oligomeric species. Furthermore, the Fourier transform infrared microspectroscopy investigation, supported by multivariate analysis, made it possible to monitor protein aggregation and the induced cell perturbations in intact cells. In particular, it has been found that the toxic oligomeric species associated with the expression of ATX3-Q55 are responsible for the main spectral changes, ascribable mainly to the cell envelope modifications. A structural alteration of the membrane detected through electron microscopy analysis in the strain expressing the pathological form supports the spectroscopic results.


Assuntos
Amiloide/genética , Proteínas Amiloidogênicas/genética , Ataxina-3/genética , Doença de Machado-Joseph/genética , Membrana Celular/genética , Proliferação de Células/genética , Escherichia coli/genética , Regulação da Expressão Gênica/genética , Humanos , Doença de Machado-Joseph/metabolismo , Doença de Machado-Joseph/patologia , Proteínas do Tecido Nervoso/genética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia
5.
Nat Commun ; 12(1): 688, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514697

RESUMO

Significant efforts have been devoted in the last twenty years to developing compounds that can interfere with the aggregation pathways of proteins related to misfolding disorders, including Alzheimer's and Parkinson's diseases. However, no disease-modifying drug has become available for clinical use to date for these conditions. One of the main reasons for this failure is the incomplete knowledge of the molecular mechanisms underlying the process by which small molecules interact with protein aggregates and interfere with their aggregation pathways. Here, we leverage the single molecule morphological and chemical sensitivity of infrared nanospectroscopy to provide the first direct measurement of the structure and interaction between single Aß42 oligomeric and fibrillar species and an aggregation inhibitor, bexarotene, which is able to prevent Aß42 aggregation in vitro and reverses its neurotoxicity in cell and animal models of Alzheimer's disease. Our results demonstrate that the carboxyl group of this compound interacts with Aß42 aggregates through a single hydrogen bond. These results establish infrared nanospectroscopy as a powerful tool in structure-based drug discovery for protein misfolding diseases.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Bexaroteno/farmacologia , Fragmentos de Peptídeos/antagonistas & inibidores , Agregação Patológica de Proteínas/tratamento farmacológico , Espectrofotometria Infravermelho/métodos , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Bexaroteno/química , Bexaroteno/uso terapêutico , Descoberta de Drogas/métodos , Estudos de Viabilidade , Humanos , Ligação de Hidrogênio , Cinética , Microscopia de Força Atômica , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Agregados Proteicos/efeitos dos fármacos , Agregação Patológica de Proteínas/patologia , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Imagem Individual de Molécula , Relação Estrutura-Atividade , Vibração
6.
Elife ; 92020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319748

RESUMO

The AAA+ protein disaggregase, Hsp104, increases fitness under stress by reversing stress-induced protein aggregation. Natural Hsp104 variants might exist with enhanced, selective activity against neurodegenerative disease substrates. However, natural Hsp104 variation remains largely unexplored. Here, we screened a cross-kingdom collection of Hsp104 homologs in yeast proteotoxicity models. Prokaryotic ClpG reduced TDP-43, FUS, and α-synuclein toxicity, whereas prokaryotic ClpB and hyperactive variants were ineffective. We uncovered therapeutic genetic variation among eukaryotic Hsp104 homologs that specifically antagonized TDP-43 condensation and toxicity in yeast and TDP-43 aggregation in human cells. We also uncovered distinct eukaryotic Hsp104 homologs that selectively antagonized α-synuclein condensation and toxicity in yeast and dopaminergic neurodegeneration in C. elegans. Surprisingly, this therapeutic variation did not manifest as enhanced disaggregase activity, but rather as increased passive inhibition of aggregation of specific substrates. By exploring natural tuning of this passive Hsp104 activity, we elucidated enhanced, substrate-specific agents that counter proteotoxicity underlying neurodegeneration.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Agregação Patológica de Proteínas/patologia , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , alfa-Sinucleína/metabolismo , Animais , Caenorhabditis elegans , Linhagem Celular , Endopeptidase Clp/genética , Endopeptidase Clp/metabolismo , Escherichia coli , Variação Genética/genética , Células HEK293 , Humanos , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Dobramento de Proteína , Deficiências na Proteostase/genética , Deficiências na Proteostase/patologia , Proteína FUS de Ligação a RNA/metabolismo , Saccharomyces cerevisiae
7.
PLoS One ; 15(9): e0223815, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32997672

RESUMO

Allium roseum is an important medicinal and aromatic plant, specific to the North African flora and a rich source of important nutrients and bioactive molecules including flavonoids and organosulfur compounds whose biological activities and pharmacological properties are well known. In the present study, the inhibition of amyloid beta protein toxicity by the ethanolic extract of this plant is investigated for the first time. Preliminary biochemical analyses identified kæmpferol and luteolin-7-o-glucoside as the more abundant phenolic compounds. The effects of A. roseum extract (ARE) on aggregation and aggregate cytotoxicity of amyloid beta-42 (Aß42), whose brain aggregates are a hallmark of Alzheimer's disease, were investigated by biophysical (ThT assay, Dynamic light scattering and transmission electron microscopy) and cellular assays (cytotoxicity, aggregate immunolocalization, ROS measurement and intracellular Ca2+ imaging). The biophysical data suggest that ARE affects the structure of the Aß42 peptide, inhibits its polymerization, and interferes with the path of fibrillogenesis. The data with cultured cells shows that ARE reduces Aß42 aggregate toxicity by inhibiting aggregate binding to the cell membrane and by decreasing both oxidative stress and intracellular Ca2+. Accordingly, ARE could act as a neuroprotective factor against Aß aggregate toxicity in Alzheimer's disease.


Assuntos
Allium/química , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Fármacos Neuroprotetores/farmacologia , Fragmentos de Peptídeos/metabolismo , Extratos Vegetais/farmacologia , Agregação Patológica de Proteínas/tratamento farmacológico , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/toxicidade , Cálcio/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Citosol/metabolismo , Avaliação Pré-Clínica de Medicamentos , Difusão Dinâmica da Luz , Etanol/química , Humanos , Microscopia Eletrônica de Transmissão , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/isolamento & purificação , Fármacos Neuroprotetores/uso terapêutico , Estresse Oxidativo/efeitos dos fármacos , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/toxicidade , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/uso terapêutico , Agregação Patológica de Proteínas/patologia , Espécies Reativas de Oxigênio/metabolismo
8.
Nat Genet ; 52(10): 1024-1035, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32989324

RESUMO

Protein aggregation is the hallmark of neurodegeneration, but the molecular mechanisms underlying late-onset Alzheimer's disease (AD) are unclear. Here we integrated transcriptomic, proteomic and epigenomic analyses of postmortem human brains to identify molecular pathways involved in AD. RNA sequencing analysis revealed upregulation of transcription- and chromatin-related genes, including the histone acetyltransferases for H3K27ac and H3K9ac. An unbiased proteomic screening singled out H3K27ac and H3K9ac as the main enrichments specific to AD. In turn, epigenomic profiling revealed gains in the histone H3 modifications H3K27ac and H3K9ac linked to transcription, chromatin and disease pathways in AD. Increasing genome-wide H3K27ac and H3K9ac in a fly model of AD exacerbated amyloid-ß42-driven neurodegeneration. Together, these findings suggest that AD involves a reconfiguration of the epigenome, wherein H3K27ac and H3K9ac affect disease pathways by dysregulating transcription- and chromatin-gene feedback loops. The identification of this process highlights potential epigenetic strategies for early-stage disease treatment.


Assuntos
Doença de Alzheimer/genética , Agregação Patológica de Proteínas/genética , Proteoma/genética , Transcriptoma/genética , Acetilação , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Cromatina/genética , Epigenoma/genética , Histona Acetiltransferases/genética , Código das Histonas/genética , Histonas/genética , Humanos , Fragmentos de Peptídeos/genética , Agregação Patológica de Proteínas/patologia , Transdução de Sinais/genética , Ativação Transcricional/genética
9.
Nat Biomed Eng ; 4(8): 787-800, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32747831

RESUMO

The prevalence of concomitant proteinopathies and heterogeneous clinical symptoms in neurodegenerative diseases hinders the identification of individuals who might be candidates for a particular intervention. Here, by applying an unsupervised clustering algorithm to post-mortem histopathological data from 895 patients with degeneration in the central nervous system, we show that six non-overlapping disease clusters can simultaneously account for tau neurofibrillary tangles, α-synuclein inclusions, neuritic plaques, inclusions of the transcriptional repressor TDP-43, angiopathy, neuron loss and gliosis. We also show that membership to the six transdiagnostic disease clusters, which explains more variance in cognitive phenotypes than can be explained by individual diagnoses, can be accurately predicted from scores of the Mini-Mental Status Exam, protein levels in cerebrospinal fluid, and genotype at the APOE and MAPT loci, via cross-validated multiple logistic regression. This combination of unsupervised and supervised data-driven tools provides a framework that could be used to identify latent disease subtypes in other areas of medicine.


Assuntos
Doenças Neurodegenerativas/classificação , Doenças Neurodegenerativas/diagnóstico , Biomarcadores/líquido cefalorraquidiano , Encéfalo/metabolismo , Encéfalo/patologia , Análise por Conglomerados , Genótipo , Humanos , Aprendizado de Máquina , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Fenótipo , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia
10.
PLoS One ; 15(8): e0233247, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857759

RESUMO

Poly(glycine-alanine) (polyGA) is one of the polydipeptides expressed in Frontotemporal Dementia and/or Amyotrophic Lateral Sclerosis 1 caused by C9ORF72 mutations and accumulates as inclusion bodies in the brain of patients. Superficially these inclusions are similar to those formed by polyglutamine (polyQ)-expanded Huntingtin exon 1 (Httex1) in Huntington's disease. Both have been reported to form an amyloid-like structure suggesting they might aggregate via similar mechanisms and therefore recruit the same repertoire of endogenous proteins. When co-expressed in the same cell, polyGA101 and Httex1(Q97) inclusions adopted immiscible phases suggesting different endogenous proteins would be enriched. Proteomic analyses identified 822 proteins in the inclusions. Only 7 were specific to polyGA and 4 specific to Httex1(Q97). Quantitation demonstrated distinct enrichment patterns for the proteins not specific to each inclusion type (up to ~8-fold normalized to total mass). The proteasome, microtubules, TriC chaperones, and translational machinery were enriched in polyGA aggregates, whereas Dnaj chaperones, nuclear envelope and RNA splicing proteins were enriched in Httex1(Q97) aggregates. Both structures revealed a collection of folding and degradation machinery including proteins in the Httex1(Q97) aggregates that are risk factors for other neurodegenerative diseases involving protein aggregation when mutated, which suggests a convergence point in the pathomechanisms of these diseases.


Assuntos
Corpos de Inclusão/metabolismo , Peptídeos/metabolismo , Proteínas/metabolismo , Animais , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Linhagem Celular , Éxons , Humanos , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Corpos de Inclusão/genética , Corpos de Inclusão/patologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Microscopia Confocal , Mutação , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Peptídeos/genética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Proteínas/genética , Proteólise , Proteoma/genética , Proteoma/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Fatores de Risco , Solubilidade
11.
Nat Med ; 26(8): 1256-1263, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32572268

RESUMO

Alzheimer's disease (AD) causes unrelenting, progressive cognitive impairments, but its course is heterogeneous, with a broad range of rates of cognitive decline1. The spread of tau aggregates (neurofibrillary tangles) across the cerebral cortex parallels symptom severity2,3. We hypothesized that the kinetics of tau spread may vary if the properties of the propagating tau proteins vary across individuals. We carried out biochemical, biophysical, MS and both cell- and animal-based-bioactivity assays to characterize tau in 32 patients with AD. We found striking patient-to-patient heterogeneity in the hyperphosphorylated species of soluble, oligomeric, seed-competent tau. Tau seeding activity correlates with the aggressiveness of the clinical disease, and some post-translational modification (PTM) sites appear to be associated with both enhanced seeding activity and worse clinical outcomes, whereas others are not. These data suggest that different individuals with 'typical' AD may have distinct biochemical features of tau. These data are consistent with the possibility that individuals with AD, much like people with cancer, may have multiple molecular drivers of an otherwise common phenotype, and emphasize the potential for personalized therapeutic approaches for slowing clinical progression of AD.


Assuntos
Doença de Alzheimer/genética , Disfunção Cognitiva/genética , Agregação Patológica de Proteínas/genética , Proteínas tau/genética , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Disfunção Cognitiva/patologia , Feminino , Heterogeneidade Genética , Humanos , Masculino , Pessoa de Meia-Idade , Emaranhados Neurofibrilares/genética , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Fosforilação , Agregação Patológica de Proteínas/patologia , Índice de Gravidade de Doença
12.
Sci Rep ; 10(1): 7721, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32382058

RESUMO

Amyloids are protein aggregates observed in several diseases, for example in Alzheimer's and Parkinson's diseases. An aggregate has a very regular beta structure with a tightly packed core, which spontaneously assumes a steric zipper form. Experimental methods enable studying such peptides, however they are tedious and costly, therefore inappropriate for genomewide studies. Several bioinformatic methods have been proposed to evaluate protein propensity to form an amyloid. However, the knowledge of aggregate structures is usually not taken into account. We propose PATH (Prediction of Amyloidogenicity by THreading) - a novel structure-based method for predicting amyloidogenicity and show that involving available structures of amyloidogenic fragments enhances classification performance. Experimental aggregate structures were used in templatebased modeling to recognize the most stable representative structural class of a query peptide. Several machine learning methods were then applied on the structural models, using their energy terms. Finally, we identified the most important terms in classification of amyloidogenic peptides. The proposed method outperforms most of the currently available methods for predicting amyloidogenicity, with its area under ROC curve equal to 0.876. Furthermore, the method gave insight into significance of selected structural features and the potentially most stable structural class of a peptide fragment if subjected to crystallization.


Assuntos
Amiloide/ultraestrutura , Fragmentos de Peptídeos/ultraestrutura , Conformação Proteica em Folha beta/genética , Software , Algoritmos , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Amiloide/química , Biologia Computacional/métodos , Humanos , Doença de Parkinson/genética , Doença de Parkinson/patologia , Fragmentos de Peptídeos/química , Agregados Proteicos/genética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia
13.
J Neuropathol Exp Neurol ; 79(6): 585-591, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32388566

RESUMO

Hyperphosphorylation, nuclear depletion, and aggregation of TDP-43 in ubiquitinated inclusions is a hallmark of frontotemporal lobar degeneration (FTLD-TDP). Evidence of potential spread of TDP-43 along synaptic connections in the human is largely limited to qualitative and semiquantitative observations. We quantitatively investigated potential transsynaptic propagation of TDP-43 across the well-established chain of single synaptic connections of the hippocampus. Hippocampi from 5 participants with clinical diagnoses of primary progressive aphasia and 2 participants with behavioral variant frontotemporal dementia, all with postmortem diagnoses of FTLD-TDP, were examined. TDP-43-positive mature (darkly stained) and pre-inclusions (diffuse puncta or fibrillar staining) in the granule cell layer of dentate gyrus (DG) and pyramidal cell layers of Cornu Ammonis (CA)3, CA2, and CA1 were quantified using unbiased stereology. The density of mature TDP-43 inclusions was higher in the DG than in the CA fields (p < 0.05). There were no differences in inclusion densities across the CA fields. TDP-43 pre-inclusions densities were not different across the 4 subregions. There was significantly higher preinclusion density than mature inclusions in CA3, but not in other subregions. Analysis of normalized total counts in place of densities revealed virtually identical results. Our finding of greatest mature inclusion deposition in the DG, coupled with more preinclusions than mature inclusions at the next relay station (CA3), and reduced densities of both in CA2-CA1, provide evidence in support of a sequential transsynaptic propagation mechanism of TDP-43 aggregates.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Degeneração Lobar Frontotemporal/patologia , Hipocampo/patologia , Agregação Patológica de Proteínas/patologia , Sinapses/patologia , Idoso , Afasia Primária Progressiva/metabolismo , Afasia Primária Progressiva/patologia , Feminino , Demência Frontotemporal/metabolismo , Demência Frontotemporal/patologia , Degeneração Lobar Frontotemporal/metabolismo , Hipocampo/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Neurônios/patologia , Agregação Patológica de Proteínas/metabolismo , Sinapses/metabolismo
14.
Sci Rep ; 10(1): 4011, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32132634

RESUMO

Protein aggregation has been one of the leading triggers of various disease conditions, such as Alzheimer's, Parkinson's and other amyloidosis. TGFBI-associated corneal dystrophies are protein aggregation disorders in which the mutant TGFBIp aggregates and accumulates in the cornea, leading to a reduction in visual acuity and blindness in severe cases. Currently, the only therapy available is invasive and there is a known recurrence after surgery. In this study, we tested the inhibitory and amyloid dissociation properties of four osmolytes in an in-vitro TGFBI peptide aggregation model. The 23-amino acid long peptide (TGFBIp 611-633 with the mutation c.623 G>R) from the 4th FAS-1 domain of TGFBIp that rapidly forms amyloid fibrils was used in the study. Several biophysical methods like Thioflavin T (ThT) fluorescence, Circular Dichroism (CD), fluorescence microscopy and Transmission electron microscopy (TEM) were used to study the inhibitory and amyloid disaggregation properties of the four osmolytes (Betaine, Raffinose, Sarcosine, and Taurine). The osmolytes were effective in both inhibiting and disaggregating the amyloid fibrils derived from TGFBIp 611-633 c.623 G>R peptide. The osmolytes did not have an adverse toxic effect on cultured human corneal fibroblast cells and could potentially be a useful therapeutic strategy for patients with TGFBIp corneal dystrophies.


Assuntos
Amiloide , Córnea , Proteínas da Matriz Extracelular , Fibroblastos , Peptídeos , Agregação Patológica de Proteínas , Fator de Crescimento Transformador beta , Amiloide/química , Amiloide/genética , Amiloide/metabolismo , Linhagem Celular , Córnea/metabolismo , Córnea/patologia , Distrofias Hereditárias da Córnea/genética , Distrofias Hereditárias da Córnea/metabolismo , Distrofias Hereditárias da Córnea/patologia , Proteínas da Matriz Extracelular/química , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Peptídeos/química , Peptídeos/genética , Peptídeos/metabolismo , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Fator de Crescimento Transformador beta/química , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo
15.
J Neuropathol Exp Neurol ; 79(4): 419-429, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32167542

RESUMO

Gerstmann-Sträussler-Scheinker (GSS) disease with P102L mutation and familial Creutzfeldt-Jakob disease (CJD) with V180I mutation are 2 major hereditary prion diseases in Japan. GSS and some familial CJD [V180I] exhibit characteristic prion protein (PrP) plaques. Overexpression of the astrocytic water channel proteins aquaporin (AQP) 1 and AQP4 was recently reported in sporadic CJD. To clarify the pathological characteristics of AQP1 and AQP4 in prion disease patient brains with plaque-type deposition, we investigated 5 patients with GSS, 2 patients with CJD [V180I], and 2 age-matched control cases without neurological diseases using immunohistochemistry and double immunofluorescence methods. We demonstrated that there is the intense expression of AQP1 and AQP4 around prion plaques, especially in distal astrocytic processes deep inside these plaques. Similar results have been reported in the senile plaques and ghost tangles of Alzheimer disease brains and a protective role of AQP4 in which AQP4 is redistributed toward the plaques and works as a barrier against the deleterious effects of these plaques has been suggested. Our results, which show a similar clustering of AQPs around PrP plaques, therefore support the possibility that AQPs also have a protective role in plaque formation in prion diseases.


Assuntos
Aquaporina 1/metabolismo , Aquaporina 4/metabolismo , Astrócitos/patologia , Encéfalo/patologia , Síndrome de Creutzfeldt-Jakob/patologia , Doença de Gerstmann-Straussler-Scheinker/patologia , Proteínas Priônicas/metabolismo , Idoso , Idoso de 80 Anos ou mais , Astrócitos/metabolismo , Encéfalo/metabolismo , Síndrome de Creutzfeldt-Jakob/metabolismo , Feminino , Doença de Gerstmann-Straussler-Scheinker/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Substância Branca/metabolismo , Substância Branca/patologia
16.
Nat Rev Neurol ; 16(4): 199-212, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32203399

RESUMO

Most neurodegenerative diseases are characterized by the intracellular or extracellular aggregation of misfolded proteins such as amyloid-ß and tau in Alzheimer disease, α-synuclein in Parkinson disease, and TAR DNA-binding protein 43 in amyotrophic lateral sclerosis. Accumulating evidence from both human studies and disease models indicates that intercellular transmission and the subsequent templated amplification of these misfolded proteins are involved in the onset and progression of various neurodegenerative diseases. The misfolded proteins that are transferred between cells are referred to as 'pathological seeds'. Recent studies have made exciting progress in identifying the characteristics of different pathological seeds, particularly those isolated from diseased brains. Advances have also been made in our understanding of the molecular mechanisms that regulate the transmission process, and the influence of the host cell on the conformation and properties of pathological seeds. The aim of this Review is to summarize our current knowledge of the cell-to-cell transmission of pathological proteins and to identify key questions for future investigation.


Assuntos
Encéfalo/metabolismo , Doenças Neurodegenerativas/metabolismo , Agregação Patológica de Proteínas/metabolismo , Transporte Proteico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Transporte Axonal , Encéfalo/patologia , Comunicação Celular , Proteínas de Ligação a DNA/metabolismo , Endocitose , Exossomos/metabolismo , Predisposição Genética para Doença , Humanos , Proteína Huntingtina/metabolismo , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Fusão de Membrana , Nanotubos , Doenças Neurodegenerativas/patologia , Neuroglia/metabolismo , Neurônios/metabolismo , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Agregação Patológica de Proteínas/patologia , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo
17.
Sci Rep ; 10(1): 5120, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198463

RESUMO

More than 20 unique diseases such as diabetes, Alzheimer's disease, Parkinson's disease are caused by the abnormal aggregations of pathogenic proteins such as amylin, ß-amyloid (Aß), and α-synuclein. All pathogenic proteins differ from each other in biological function, primary sequences, and morphologies; however, the proteins are toxic when aggregated. Here, we investigated the cellular toxicity of pathogenic or non-pathogenic protein aggregates. In this study, six proteins were selected and they were incubated at acid pH and high temperature. The aggregation kinetic and cellular toxicity of protein species with time were characterized. Three non-pathogenic proteins, bovine serum albumin (BSA), catalase, and pepsin at pH 2 and 65 °C were stable in protein structure and non-toxic at a lower concentration of 1 mg/mL. They formed aggregates at a higher concentration of 20 mg/mL with time and they induced the toxicity in short incubation time points, 10 min and 20 min only and they became non-toxic after 30 min. Other three pathogenic proteins, lysozyme, superoxide dismutase (SOD), and insulin, also produced the aggregates with time and they caused cytotoxicity at both 1 mg/mL and 20 mg/mL after 10 min. TEM images and DSC analysis demonstrated that fibrils or aggregates at 1 mg/mL induced cellular toxicity due to low thermal stability. In DSC data, fibrils or aggregates of pathogenic proteins had low thermal transition compared to fresh samples. The results provide useful information to understand the aggregation and cellular toxicity of pathogenic and non-pathogenic proteins.


Assuntos
Catalase/metabolismo , Insulina/metabolismo , Muramidase/metabolismo , Pepsina A/metabolismo , Agregados Proteicos/fisiologia , Agregação Patológica de Proteínas/patologia , Soroalbumina Bovina/metabolismo , Superóxido Dismutase/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Linhagem Celular , Diabetes Mellitus/genética , Diabetes Mellitus/patologia , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Modelos Moleculares , Doença de Parkinson/genética , Doença de Parkinson/patologia , Estrutura Secundária de Proteína/fisiologia , alfa-Sinucleína/metabolismo
18.
Int J Mol Sci ; 21(4)2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32098273

RESUMO

Human cells express large amounts of different proteins continuously that must fold into well-defined structures that need to remain correctly folded and assemble in order to ensure their cellular and biological functions. The integrity of this protein balance/homeostasis, also named proteostasis, is maintained by the proteostasis network (PN). This integrated biological system, which comprises about 2000 proteins (chaperones, folding enzymes, degradation components), control and coordinate protein synthesis folding and localization, conformational maintenance, and degradation. This network is particularly challenged by mutations such as those found in genetic diseases, because of the inability of an altered peptide sequence to properly engage PN components that trigger misfolding and loss of function. Thus, deletions found in the ΔF508 variant of the Cystic Fibrosis (CF) transmembrane regulator (CFTR) triggering CF or missense mutations found in the Z variant of Alpha 1-Antitrypsin deficiency (AATD), leading to lung and liver diseases, can accelerate misfolding and/or generate aggregates. Conversely to CF variants, for which three correctors are already approved (ivacaftor, lumacaftor/ivacaftor, and most recently tezacaftor/ivacaftor), there are limited therapeutic options for AATD. Therefore, a more detailed understanding of the PN components governing AAT variant biogenesis and their manipulation by pharmacological intervention could delay, or even better, avoid the onset of AATD-related pathologies.


Assuntos
Agregação Patológica de Proteínas/metabolismo , Dobramento de Proteína , Deficiências na Proteostase/metabolismo , Proteostase , Deficiência de alfa 1-Antitripsina/metabolismo , Humanos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Deficiências na Proteostase/genética , Deficiências na Proteostase/patologia , Deficiência de alfa 1-Antitripsina/genética , Deficiência de alfa 1-Antitripsina/patologia
19.
Curr Protoc Neurosci ; 91(1): e88, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32049438

RESUMO

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by motor symptoms such as tremor, slowness of movement, rigidity, and postural instability, as well as non-motor features like sleep disturbances, loss of ability to smell, depression, constipation, and pain. Motor symptoms are caused by depletion of dopamine in the striatum due to the progressive loss of dopamine neurons in the substantia nigra pars compacta. Approximately 10% of PD cases are familial arising from genetic mutations in α-synuclein, LRRK2, DJ-1, PINK1, parkin, and several other proteins. The majority of PD cases are, however, idiopathic, i.e., having no clear etiology. PD is characterized by progressive accumulation of insoluble inclusions, known as Lewy bodies, mostly composed of α-synuclein and membrane components. The cause of PD is currently attributed to cellular proteostasis deregulation and mitochondrial dysfunction, which are likely interdependent. In addition, neuroinflammation is present in brains of PD patients, but whether it is the cause or consequence of neurodegeneration remains to be studied. Rodents do not develop PD or PD-like motor symptoms spontaneously; however, neurotoxins, genetic mutations, viral vector-mediated transgene expression and, recently, injections of misfolded α-synuclein have been successfully utilized to model certain aspects of the disease. Here, we critically review the advantages and drawbacks of rodent PD models and discuss approaches to advance pre-clinical PD research towards successful disease-modifying therapy. © 2020 The Authors.


Assuntos
Neurotoxinas/toxicidade , Transtornos Parkinsonianos , Animais , Corpo Estriado/efeitos dos fármacos , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/ultraestrutura , Avaliação Pré-Clínica de Medicamentos/métodos , Previsões , Estudo de Associação Genômica Ampla , Técnicas Histológicas , Humanos , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/análise , Proteínas do Tecido Nervoso/genética , Fármacos Neuroprotetores/uso terapêutico , Doença de Parkinson/genética , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/tratamento farmacológico , Transtornos Parkinsonianos/genética , Transtornos Parkinsonianos/patologia , Praguicidas/toxicidade , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Ratos , Substância Negra/efeitos dos fármacos , Sinucleinopatias/genética , Sinucleinopatias/patologia , alfa-Sinucleína/biossíntese , alfa-Sinucleína/genética
20.
Cell ; 180(4): 633-644.e12, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-32032505

RESUMO

Tau aggregation into insoluble filaments is the defining pathological hallmark of tauopathies. However, it is not known what controls the formation and templated seeding of strain-specific structures associated with individual tauopathies. Here, we use cryo-electron microscopy (cryo-EM) to determine the structures of tau filaments from corticobasal degeneration (CBD) human brain tissue. Cryo-EM and mass spectrometry of tau filaments from CBD reveal that this conformer is heavily decorated with posttranslational modifications (PTMs), enabling us to map PTMs directly onto the structures. By comparing the structures and PTMs of tau filaments from CBD and Alzheimer's disease, it is found that ubiquitination of tau can mediate inter-protofilament interfaces. We propose a structure-based model in which cross-talk between PTMs influences tau filament structure, contributing to the structural diversity of tauopathy strains. Our approach establishes a framework for further elucidating the relationship between the structures of polymorphic fibrils, including their PTMs, and neurodegenerative disease.


Assuntos
Processamento de Proteína Pós-Traducional , Tauopatias/metabolismo , Proteínas tau/química , Idoso , Microscopia Crioeletrônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Tauopatias/patologia , Proteínas tau/metabolismo
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