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1.
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
2.
Nat Commun ; 11(1): 411, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31964863

RESUMO

Alzheimer's disease (AD) is characterized by amyloid plaques and progressive cerebral atrophy. Here, we report FAM222A as a putative brain atrophy susceptibility gene. Our cross-phenotype association analysis of imaging genetics indicates a potential link between FAM222A and AD-related regional brain atrophy. The protein encoded by FAM222A is predominantly expressed in the CNS and is increased in brains of patients with AD and in an AD mouse model. It accumulates within amyloid deposits, physically interacts with amyloid-ß (Aß) via its N-terminal Aß binding domain, and facilitates Aß aggregation. Intracerebroventricular infusion or forced expression of this protein exacerbates neuroinflammation and cognitive dysfunction in an AD mouse model whereas ablation of this protein suppresses the formation of amyloid deposits, neuroinflammation and cognitive deficits in the AD mouse model. Our data support the pathological relevance of protein encoded by FAM222A in AD.


Assuntos
Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Disfunção Cognitiva/genética , Proteínas do Tecido Nervoso/genética , Placa Amiloide/genética , Agregação Patológica de Proteínas/genética , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/patologia , Animais , Atrofia/diagnóstico por imagem , Atrofia/genética , Atrofia/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Disfunção Cognitiva/patologia , Conjuntos de Dados como Assunto , Modelos Animais de Doenças , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/metabolismo , Placa Amiloide/patologia , Polimorfismo de Nucleotídeo Único , Agregação Patológica de Proteínas/diagnóstico por imagem , Agregação Patológica de Proteínas/patologia
3.
PLoS One ; 15(1): e0227227, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978114

RESUMO

Many conflicting reports about the involvement of serum amyloid P component (SAP) in amyloid diseases have been presented over the years; SAP is known to be a universal component of amyloid aggregates but it has been suggested that it can both induce and suppress amyloid formation. By using our Drosophila model of systemic lysozyme amyloidosis, SAP has previously been shown to reduce the toxicity induced by the expression of the disease-associated lysozyme variant, F57I, in the Drosophila central nervous system. This study further investigates the involvement of SAP in modulating lysozyme toxicity using histochemistry and spectral analyses on the double transgenic WT and F57I lysozyme flies to probe; i) formation of aggregates, ii) morphological differences of the aggregated lysozyme species formed in the presence or absence of SAP, iii) location of lysozyme and iv) co-localisation of lysozyme and SAP in the fly brain. We found that SAP can counteract the toxicity (measured by the reduction in the median survival time) induced by F57I lysozyme by converting toxic F57I species into less toxic amyloid-like structures, as reflected by the spectral changes that p-FTAA undergoes when bound to lysozyme deposits in F57I-F57I-SAP flies as compared to F57I-F57I flies. Indeed, when SAP was introduced to in vitro lysozyme fibril formation, the endpoint fibrils had enhanced ThT fluorescence intensity as compared to lysozyme fibrils alone. This suggests that a general mechanism for SAP's role in amyloid diseases may be to promote the formation of stable, amyloid-like fibrils, thus decreasing the impact of toxic species formed along the aggregation pathway.


Assuntos
Amiloidose/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Muramidase/metabolismo , Componente Amiloide P Sérico/metabolismo , Amiloide/genética , Amiloide/metabolismo , Amiloide/ultraestrutura , Amiloidose/genética , Amiloidose/patologia , Animais , Animais Geneticamente Modificados , Modelos Animais de Doenças , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Humanos , Muramidase/genética , Agregados Proteicos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia
4.
Int J Mol Sci ; 20(19)2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31547024

RESUMO

Although the causative role of the accumulation of amyloid ß 1-42 (Aß42) deposits in the pathogenesis of Alzheimer's disease (AD) has been under debate for many years, it is supposed that the toxicity soluble oligomers of Tau protein (TauOs) might be also the pathogenic factor acting on the initial stages of this disease. Therefore, we performed a thorough search for literature pertaining to our investigation via the MEDLINE/PubMed database. It was shown that soluble TauOs, especially granular forms, may be the most toxic form of this protein. Hyperphosphorylated TauOs can reduce the number of synapses by missorting into axonal compartments of neurons other than axon. Furthermore, soluble TauOs may be also responsible for seeding Tau pathology within AD brains, with probable link to AßOs toxicity. Additionally, the concentrations of TauOs in the cerebrospinal fluid (CSF) and plasma of AD patients were higher than in non-demented controls, and revealed a negative correlation with mini-mental state examination (MMSE) scores. It was postulated that adding the measurements of TauOs to the panel of CSF biomarkers could improve the diagnosis of AD.


Assuntos
Doença de Alzheimer/metabolismo , Agregação Patológica de Proteínas/metabolismo , Dobramento de Proteína , Deficiências na Proteostase/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/patologia , Animais , Humanos , Agregação Patológica de Proteínas/diagnóstico , Agregação Patológica de Proteínas/patologia , Deficiências na Proteostase/diagnóstico , Deficiências na Proteostase/patologia
5.
Clin Biochem ; 73: 26-31, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31400306

RESUMO

Neuropathological diagnostic criteria of neurodegenerative disorders are based on the presence of specific inclusions in a specific area of brain tissue that correlate with clinical manifestations. Concomitant neurodegenerative disorders correspond to a combination of two (or more) different fully developed diseases in the same patient. Concomitant neurodegenerative pathology represents the presence of definite neurodegeneration and deposits of pathological proteins specific for another disease, which is not, however, fully developed. Very frequent overlaps include Alzheimer's disease and alpha-synuclein inclusions. Nevertheless, careful neuropathological investigations reveal an increasing frequency of different co-pathologies in examined brains. In Alzheimer's disease, protein TDP-43 may co-aggregate, but it is not clear whether this is atypical isolated Alzheimer's disease or overlap of Alzheimer's disease with early frontotemporal lobar degeneration. Comorbidities of Alzheimer's disease and tauopathies are relatively rare. A combination of vascular pathology with primary neurodegeneration (mostly Alzheimer's disease or dementia with Lewy bodies) is historically called mixed dementia. Overlap of different neuropathologically confirmed neurodegenerations could lead to atypical and unusual clinical presentations and may be responsible for faster disease progression. Several CSF biomarkers have been evaluated for their utility in diagnostic processes in different neurodegenerative dementias; however, evidence regarding their role in neurodegenerative overlaps is still limited.


Assuntos
Doença de Alzheimer/metabolismo , Proteínas de Ligação a DNA/metabolismo , Doença por Corpos de Lewy/metabolismo , Agregação Patológica de Proteínas/metabolismo , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/patologia , Biomarcadores/metabolismo , Humanos , Doença por Corpos de Lewy/patologia , Agregação Patológica de Proteínas/patologia
6.
Mol Med Rep ; 20(4): 3363-3370, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31432127

RESUMO

The present study aimed to explore the effects of histone deacetylase 6 (HDAC6) on brain injury in rats induced by apolipoprotein E4 (APOE4) and amyloid ß protein alloform 1­40 (Aß1­40) copolymerization. The rats were randomly divided into four groups: Control group, sham group, APOE4 + Aß1­40 co­injection group (model group) and HDAC6 inhibitor group (HDAC6 group). The brain injury model was established by co­injection of APOE4 + Aß1­40. Morris water maze experiment was used to observe the spatial memory and learning the ability of rats. Histological changes of the hippocampus were observed by hematoxylin and eosin staining. The mRNA expression levels of choline acetyltransferase (ChAT) and HDAC6 were detected by reverse transcription­quantitative PCR. Immunohistochemistry was used to detect the protein expression of HDAC6. Western blotting was used to detect the protein expression levels of HDAC6, microtubule­associated protein tau and glycogen synthase kinase 3ß (GSK3ß). APOE4 and Aß1­40 co­aggregation decreased the short­term spatial memory and learning ability of rats, whereas inhibition of HDAC6 activity attenuated the injury. Inhibition of HDAC6 activity resulted in an attenuation of the APOE4 and Aß1­40 co­aggregation­induced increase in the number of dysplastic hippocampal cells. Further experiments demonstrated that APOE4 and Aß1­40 co­aggregation decreased the expression levels of ChAT mRNA, and the phosphorylation levels of tau GSK3ß protein in the hippocampus, whereas inhibition of HDAC6 activity resulted in increased expression of ChAT mRNA, tau protein and GSK3ß phosphorylation. The inhibition of HDAC6 activity was also demonstrated to reduce brain injury induced by APOE4 and Aß1­40 co­aggregation in model rats.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apolipoproteína E4/metabolismo , Lesões Encefálicas/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Hipocampo/metabolismo , Desacetilase 6 de Histona/biossíntese , Inibidores de Histona Desacetilases/farmacologia , Fragmentos de Peptídeos/metabolismo , Agregação Patológica de Proteínas/metabolismo , Animais , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Colina O-Acetiltransferase/biossíntese , Hipocampo/patologia , Hipocampo/fisiopatologia , Desacetilase 6 de Histona/antagonistas & inibidores , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Agregação Patológica de Proteínas/patologia , Agregação Patológica de Proteínas/fisiopatologia , Ratos , Ratos Sprague-Dawley , Memória Espacial/efeitos dos fármacos , Proteínas tau/metabolismo
7.
Nat Commun ; 10(1): 3090, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300647

RESUMO

The role of brain somatic mutations in Alzheimer's disease (AD) is not well understood. Here, we perform deep whole-exome sequencing (average read depth 584×) in 111 postmortem hippocampal formation and matched blood samples from 52 patients with AD and 11 individuals not affected by AD. The number of somatic single nucleotide variations (SNVs) in AD brain specimens increases significantly with aging, and the rate of mutation accumulation in the brain is 4.8-fold slower than that in AD blood. The putatively pathogenic brain somatic mutations identified in 26.9% (14 of 52) of AD individuals are enriched in PI3K-AKT, MAPK, and AMPK pathway genes known to contribute to hyperphosphorylation of tau. We show that a pathogenic brain somatic mutation in PIN1 leads to a loss-of-function mutation. In vitro mimicking of haploinsufficiency of PIN1 aberrantly increases tau phosphorylation and aggregation. This study provides new insights into the genetic architecture underlying the pathogenesis of AD.


Assuntos
Doença de Alzheimer/genética , Peptidilprolil Isomerase de Interação com NIMA/genética , Agregação Patológica de Proteínas/genética , Proteínas tau/metabolismo , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Doença de Alzheimer/patologia , Animais , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Haploinsuficiência , Hipocampo/citologia , Hipocampo/patologia , Humanos , Mutação com Perda de Função , Masculino , Camundongos , Pessoa de Meia-Idade , Taxa de Mutação , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Neurônios , Fosforilação/genética , Polimorfismo de Nucleotídeo Único , Agregação Patológica de Proteínas/patologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sequenciamento Completo do Exoma
8.
PLoS One ; 14(7): e0219486, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31291334

RESUMO

The prominent characteristic of Alzheimer's disease (AD) is the accumulation of amyloid beta (Abeta) proteins in the form of plaques that cause molecular and cellular alterations in the brain. Due to the paucity of brain samples of early-stage Abeta aggregation, animal models have been developed to study early events in AD. Caenorhabditis elegans is a genetically tractable animal model for AD. Here, we used transcriptomic data, network-based protein-protein interactions and weighted gene co-expression network analysis (WGCNA), to detect modules and their gene ontology in response to Abeta aggregation in C. elegans. Additionally, hub genes and their orthologues in human and mouse were identified to study their relation to AD. We also found several transcription factors (TFs) responding to Abeta accumulation. Our results show that Abeta expression in C. elegans relates to general processes such as molting cycle, locomotion, and larval development plus AD-associated processes, including protein phosphorylation, and G-protein coupled receptor-regulated pathways. We reveal that many hub genes and TFs including ttbk-2, daf-16, and unc-49 have human and mouse orthologues that are directly or potentially associated with AD and neural development. In conclusion, using systems biology we identified important genes and biological processes in C. elegans that respond to Abeta aggregation, which could be used as potential diagnostic or therapeutic targets. In addition, because of evolutionary relationship to AD in human, we suggest that C. elegans is a useful model for studying early molecular events in AD.


Assuntos
Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Redes Reguladoras de Genes , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Humanos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Mapas de Interação de Proteínas , Homologia de Sequência do Ácido Nucleico , Biologia de Sistemas
9.
Nat Commun ; 10(1): 2479, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31171783

RESUMO

The tauopathy-like phenotype observed in the rTg4510 mouse line, in which human tauP301L expression specifically within the forebrain can be temporally controlled, has largely been attributed to high overexpression of mutant human tau in the forebrain region. Unexpectedly, we found that in a different mouse line with a targeted-insertion of the same transgene driven by the same tetracycline-TransActivator (tTA) allele, but with even higher overexpression of tauP301L than rTg4510, atrophy and tau histopathology are delayed, and a different behavioral profile is observed. This suggests that it is not overexpression of mutant human tau alone that contributes to the phenotype in rTg4510 mice. Furthermore we show that the tauopathy-like phenotype seen in rTg4510 requires a ~70-copy tau-transgene insertion in a 244 kb deletion in Fgf14, a ~7-copy tTA-transgene insertion in a 508 kb deletion that disrupts another five genes, in addition to high transgene overexpression. We propose that these additional effects need to be accounted for in any studies using rTg4510.


Assuntos
Modelos Animais de Doenças , Fatores de Crescimento de Fibroblastos/genética , Camundongos , Prosencéfalo/metabolismo , Agregação Patológica de Proteínas/genética , Tauopatias/genética , Proteínas tau/genética , Animais , Atrofia , Camundongos Transgênicos , Fenótipo , Prosencéfalo/patologia , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Tauopatias/metabolismo , Tauopatias/patologia
10.
BMB Rep ; 52(6): 349-359, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31186086

RESUMO

After the first research declaring the generation of human induced pluripotent stem cells (hiPSCs) in 2007, several attempts have been made to model neurodegenerative disease in vitro during the past decade. Parkinson's disease (PD) is the second most common neurodegenerative disorder, which is mainly characterized by motor dysfunction. The formation of unique and filamentous inclusion bodies called Lewy bodies (LBs) is the hallmark of both PD and dementia with LBs. The key pathology in PD is generally considered to be the alpha-synuclein (α-syn) accumulation, although it is still controversial whether this protein aggregation is a cause or consequence of neurodegeneration. In the present work, the recently published researches which recapitulated the α-syn aggregation phenomena in sporadic and familial PD hiPSC models were reviewed. Furthermore, the advantages and potentials of using patient-derived PD hiPSC with focus on α-syn aggregation have been discussed. [BMB Reports 2019; 52(6): 349-359].


Assuntos
Células-Tronco Pluripotentes Induzidas/metabolismo , Doença de Parkinson/patologia , alfa-Sinucleína/metabolismo , Humanos , Corpos de Lewy/metabolismo , Corpos de Lewy/fisiologia , Doenças Neurodegenerativas/metabolismo , Doença de Parkinson/metabolismo , Agregação Patológica de Proteínas/patologia , alfa-Sinucleína/fisiologia
11.
Nat Commun ; 10(1): 2394, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160584

RESUMO

To understand the molecular processes that link Aß amyloidosis, tauopathy and neurodegeneration, we screened for tau-interacting proteins by immunoprecipitation/LC-MS. We identified the carboxy-terminal PDZ ligand of nNOS (CAPON) as a novel tau-binding protein. CAPON is an adaptor protein of neuronal nitric oxide synthase (nNOS), and activated by the N-methyl-D-aspartate receptor. We observed accumulation of CAPON in the hippocampal pyramidal cell layer in the AppNL-G-F -knock-in (KI) brain. To investigate the effect of CAPON accumulation on Alzheimer's disease (AD) pathogenesis, CAPON was overexpressed in the brain of AppNL-G-F mice crossbred with MAPT (human tau)-KI mice. This produced significant hippocampal atrophy and caspase3-dependent neuronal cell death in the CAPON-expressing hippocampus, suggesting that CAPON accumulation increases neurodegeneration. CAPON expression also induced significantly higher levels of phosphorylated, oligomerized and insoluble tau. In contrast, CAPON deficiency ameliorated the AD-related pathological phenotypes in tauopathy model. These findings suggest that CAPON could be a druggable AD target.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doença de Alzheimer/metabolismo , Hipocampo/metabolismo , Agregação Patológica de Proteínas/metabolismo , Células Piramidais/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Precursor de Proteína beta-Amiloide/genética , Animais , Atrofia , Caspase 3/metabolismo , Morte Celular , Cromatografia Líquida , Modelos Animais de Doenças , Técnicas de Introdução de Genes , Hipocampo/patologia , Humanos , Imunoprecipitação , Espectrometria de Massas , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Agregação Patológica de Proteínas/patologia , Células Piramidais/patologia , Tauopatias , Proteínas tau/metabolismo
12.
Nat Struct Mol Biol ; 26(7): 619-627, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31235914

RESUMO

The DNA and RNA processing protein TDP-43 undergoes both functional and pathogenic aggregation. Functional TDP-43 aggregates form reversible, transient species such as nuclear bodies, stress granules, and myo-granules. Pathogenic, irreversible TDP-43 aggregates form in amyotrophic lateral sclerosis and other neurodegenerative conditions. Here we find the features of TDP-43 fibrils that confer both reversibility and irreversibility by determining structures of two segments reported to be the pathogenic cores of human TDP-43 aggregation: SegA (residues 311-360), which forms three polymorphs, all with dagger-shaped folds; and SegB A315E (residues 286-331 containing the amyotrophic lateral sclerosis hereditary mutation A315E), which forms R-shaped folds. Energetic analysis suggests that the dagger-shaped polymorphs represent irreversible fibril structures, whereas the SegB polymorph may participate in both reversible and irreversible fibrils. Our structures reveal the polymorphic nature of TDP-43 and suggest how the A315E mutation converts the R-shaped polymorph to an irreversible form that enhances pathology.


Assuntos
Amiloide/ultraestrutura , Proteínas de Ligação a DNA/ultraestrutura , Sequência de Aminoácidos , Amiloide/química , Amiloide/genética , Microscopia Crioeletrônica , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Humanos , Modelos Moleculares , Mutação Puntual , Agregados Proteicos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Conformação Proteica , Dobramento de Proteína , Estabilidade Proteica
13.
ACS Chem Biol ; 14(7): 1593-1600, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31074957

RESUMO

The self-assembly of proteins into structured fibrillar aggregates is associated with a range of neurodegenerative diseases, including Alzheimer's and Parkinson's diseases, in which an important cytotoxic role is thought to be played by small soluble oligomers accumulating during the aggregation process or released by mature fibrils. As the structural characteristics of such species and their links with toxicity are still not fully defined, we have compared six examples of preformed misfolded protein oligomers with different ß-sheet content, as determined using Fourier transform infrared spectroscopy, and with different toxicity, as determined by three cellular readouts of cell viability. The results show the absence of any measurable correlation between the nature of their secondary structure and their cellular toxicity, both when comparing the six types of oligomers as a group and when comparing species in subgroups characterized by either the same size or the same exposure of hydrophobic moieties.


Assuntos
Peptídeos beta-Amiloides/química , Agregação Patológica de Proteínas/patologia , Deficiências na Proteostase/patologia , alfa-Sinucleína/química , Doença de Alzheimer/patologia , Carboxil e Carbamoil Transferases/química , Linhagem Celular , Sobrevivência Celular , Escherichia coli/química , Proteínas de Escherichia coli/química , Humanos , Doença de Parkinson/patologia , Dobramento de Proteína , Estrutura Secundária de Proteína
14.
Biochem J ; 476(10): 1401-1417, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31036717

RESUMO

In Alzheimer's disease, tau is predominantly acetylated at K174, K274, K280, and K281 residues. The acetylation of K274-tau is linked with memory loss and dementia. In this study, we have examined the molecular mechanism of the toxicity of acetylated K274-tau. We incorporated an acetylation mimicking mutation at K274 (K→Q) residue of tau. The mutation (K274Q) strongly reduced the ability of tau to bind to tubulin and also to polymerize tubulin while K274R mutation did not reduce the ability of tau either to bind or polymerize tubulin. In addition, K274Q-tau displayed a higher aggregation propensity than wild-type tau as evident from thioflavin S fluorescence, tryptophan fluorescence, and electron microscopic images. Furthermore, dynamic light scattering, atomic force microscopy, and dot blot analysis using an oligomer-specific antibody suggested that K274Q mutation enhanced the oligomerization of tau. The K274Q mutation also strongly decreased the critical concentration for the liquid-liquid phase separation of tau. The oligomeric forms of K274Q-tau were found to be more toxic than wild tau to neuroblastoma cells. Using circular dichroism and fluorescence spectroscopy, we provide evidence indicating that the acetylation mimicking mutation (K274Q) induced conformational changes in tau. The results suggested that the acetylation of tau at 274 residues can increase tau aggregation and enhance the cytotoxicity of tau oligomers.


Assuntos
Mutação de Sentido Incorreto , Agregação Patológica de Proteínas , Tubulina (Proteína) , Proteínas tau , Acetilação , Substituição de Aminoácidos , Linhagem Celular Tumoral , Humanos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Tubulina (Proteína)/química , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Proteínas tau/química , Proteínas tau/genética , Proteínas tau/metabolismo
15.
Int J Mol Sci ; 20(9)2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31071995

RESUMO

Human apolipoprotein E (apoE) is a major component of lipoprotein particles, and under physiological conditions, is involved in plasma cholesterol transport. Human apolipoprotein E found in three isoforms (E2; E3; E4) is a member of a family of apolipoproteins that under pathological conditions are detected in extracellular amyloid depositions in several amyloidoses. Interestingly, the lipid-free apoE form has been shown to be co-localized with the amyloidogenic Aß peptide in amyloid plaques in Alzheimer's disease, whereas in particular, the apoE4 isoform is a crucial risk factor for late-onset Alzheimer's disease. Evidence at the experimental level proves that apoE self-assembles into amyloid fibrilsin vitro, although the misfolding mechanism has not been clarified yet. Here, we explored the mechanistic insights of apoE misfolding by testing short apoE stretches predicted as amyloidogenic determinants by AMYLPRED, and we computationally investigated the dynamics of apoE and an apoE-Αß complex. Our in vitro biophysical results prove that apoE peptide-analogues may act as the driving force needed to trigger apoE aggregation and are supported by the computational apoE outcome. Additional computational work concerning the apoE-Αß complex also designates apoE amyloidogenic regions as important binding sites for oligomeric Αß; taking an important step forward in the field of Alzheimer's anti-aggregation drug development.


Assuntos
Doença de Alzheimer/genética , Peptídeos beta-Amiloides/química , Amiloidose/genética , Apolipoproteínas E/química , Doença de Alzheimer/patologia , Amiloide/química , Amiloide/genética , Amiloide/ultraestrutura , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/ultraestrutura , Amiloidose/patologia , Apolipoproteínas E/ultraestrutura , Sítios de Ligação , Colesterol/química , Colesterol/genética , Humanos , Placa Amiloide/genética , Placa Amiloide/patologia , Placa Amiloide/ultraestrutura , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Dobramento de Proteína , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/ultraestrutura
16.
J Biol Chem ; 294(19): 7917-7930, 2019 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-30936201

RESUMO

Tauopathies are a diverse class of neurodegenerative diseases characterized by the formation of insoluble tau aggregates and the loss of cellular function and neuronal death. Tau inclusions have been shown to contain a number of proteins, including molecular chaperones, but the consequences of these entrapments are not well established. Here, using a human cell system for seeding-dependent tau aggregation, we demonstrate that the molecular chaperones heat-shock cognate 71-kDa protein (HSC70)/heat-shock protein 70 (HSP70), HSP90, and J-domain co-chaperones are sequestered by tau aggregates. By employing single-cell analysis of protein-folding and clathrin-mediated endocytosis, we show that both chaperone-dependent cellular activities are significantly impaired by tau aggregation and can be reversed by treatment with small-molecule regulators of heat-shock transcription factor 1 (HSF1) proteostasis that induce the expression of cytosolic chaperones. These results reveal that the sequestration of cytoplasmic molecular chaperones by tau aggregates interferes with two arms of the proteostasis network, likely having profound negative consequences for cellular function.


Assuntos
Vesículas Citoplasmáticas/metabolismo , Agregação Patológica de Proteínas/metabolismo , Dobramento de Proteína , Proteostase , Proteínas tau/metabolismo , Vesículas Citoplasmáticas/genética , Vesículas Citoplasmáticas/patologia , Células HEK293 , Proteínas de Choque Térmico HSC70/genética , Proteínas de Choque Térmico HSC70/metabolismo , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Fatores de Transcrição de Choque Térmico/genética , Fatores de Transcrição de Choque Térmico/metabolismo , Humanos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia , Transporte Proteico , Proteínas tau/genética
17.
PLoS One ; 14(4): e0215277, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31022188

RESUMO

Most of the Parkinson's disease (PD) cases are sporadic, although several genes are directly related to PD. Several pathways are central in PD pathogenesis: protein aggregation linked to proteasomal impairments, mitochondrial dysfunctions and impairment in dopamine (DA) release. Here we studied the close crossing of mitochondrial dysfunction and aggregation of α-synuclein (α-syn) and in the extension in the dopaminergic neuronal death. Here, using rat primary cultures of mesencephalic neurons, we induced the mitochondrial impairments using "DA-toxins" (MPP+, 6OHDA, rotenone). We showed that the DA-Toxins induced dopaminergic cell death through different pathways: caspase-dependent cell death for 6OHDA; MPP+ stimulated caspase-independent cell death, and rotenone activated both pathways. In addition, a decrease in energy production and/or a development of oxidative stress were observed and were linked to α-syn aggregation with generation of Lewy body-like inclusions (found inside and outside the dopaminergic neurons). We demonstrated that any of induced mitochondrial disturbances and processes of death led to α-syn protein aggregation and finally to cell death. Our study depicts the cell death mechanisms taking place in in vitro models of Parkinson's disease and how mitochondrial dysfunctions is at the cross road of the pathologies of this disease.


Assuntos
Neurônios Dopaminérgicos/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Neurotoxinas/toxicidade , Doença de Parkinson/patologia , Agregação Patológica de Proteínas/patologia , 1-Metil-4-fenilpiridínio/toxicidade , Animais , Apoptose/efeitos dos fármacos , Células Cultivadas , Neurônios Dopaminérgicos/citologia , Neurônios Dopaminérgicos/patologia , Embrião de Mamíferos , Metabolismo Energético/efeitos dos fármacos , Feminino , Humanos , Mesencéfalo/citologia , Mitocôndrias/metabolismo , Necrose/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Oxidopamina/toxicidade , Doença de Parkinson/etiologia , Cultura Primária de Células , Agregação Patológica de Proteínas/etiologia , Ratos , Rotenona/toxicidade , alfa-Sinucleína/metabolismo
18.
Molecules ; 24(8)2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-31022909

RESUMO

Fused in sarcoma (FUS) is a DNA/RNA binding protein that is involved in RNA metabolism and DNA repair. Numerous reports have demonstrated by pathological and genetic analysis that FUS is associated with a variety of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and polyglutamine diseases. Traditionally, the fibrillar aggregation of FUS was considered to be the cause of those diseases, especially via its prion-like domains (PrLDs), which are rich in glutamine and asparagine residues. Lately, a nonfibrillar self-assembling phenomenon, liquid-liquid phase separation (LLPS), was observed in FUS, and studies of its functions, mechanism, and mutual transformation with pathogenic amyloid have been emerging. This review summarizes recent studies on FUS self-assembling, including both aggregation and LLPS as well as their relationship with the pathology of ALS, FTLD, and other neurodegenerative diseases.


Assuntos
Doenças Neurodegenerativas/genética , Agregação Patológica de Proteínas/genética , Proteína FUS de Ligação a RNA/química , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Asparagina/química , Asparagina/genética , Degeneração Lobar Frontotemporal/genética , Degeneração Lobar Frontotemporal/patologia , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/genética , Humanos , Doenças Neurodegenerativas/patologia , Peptídeos/química , Peptídeos/genética , Príons/química , Príons/genética , Agregação Patológica de Proteínas/patologia , Domínios Proteicos/genética , Proteína FUS de Ligação a RNA/genética
19.
Neurobiol Dis ; 127: 350-361, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30910747

RESUMO

Congenital generalized lipodystrophy 2 (CGL2) is characterized by loss of adipose tissue, insulin resistance and cognitive deficits and caused by mutation of BSCL2/seipin gene. Seipin deletion in mice and rats causes severe lipodystrophy, insulin resistance, and cognitive impairment. Hippocampal neurons express seipin protein. This study aimed to investigate the influence of systemic seipin knockout (seipin-sKO), neuronal seipin knockout (seipin-nKO) or adipose seipin knockout (seipin-aKO) in hippocampal tau phosphorylation and aggregation. Levels of tau phosphorylation at Thr212/Ser214 and Ser202/Thr205 and oligomer tau protein were increased in seipin-sKO mice and seipin-nKO mice with a decrease in axonal density and expression of PPARγ. Neuronal seipin deletion increased activities of GSK3ß and Akt/mTOR signaling, which were corrected by the administration of PPARγ agonist rosiglitazone for 7 days. The autophagosome formation was reduced in seipin-sKO mice and seipin-nKO mice, which was rescued by the Akt and mTOR inhibitors. The administration of rosiglitazone or Akt, mTOR and GSK3ß inhibitors for 7 days could correct the hyperphosphorylation and aggregation of tau. On the other hand, seipin-sKO mice appeared insulin resistance and an increase in phosphorylation of tau at Ser396 and JNK, which were corrected by treatment with rosiglitazone for 30 days rather than 7 days. Inhibition of JNK in seipin-sKO mice corrected the hyperphosphorylated tau at Ser396. The results indicate that neuronal seipin deletion causes hyperphosphorylation and aggregation of tau protein leading to axonal atrophy through reduced PPARγ to enhance GSK3ß and Akt/mTOR signaling; systemic seipin deletion-induced insulin resistance causes tau hyperphosphorylation via cascading JNK pathway.


Assuntos
Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Hipocampo/metabolismo , Resistência à Insulina/fisiologia , Neurônios/metabolismo , PPAR gama/metabolismo , Proteínas tau/metabolismo , Animais , Axônios/metabolismo , Axônios/patologia , Subunidades gama da Proteína de Ligação ao GTP/genética , Glicogênio Sintase Quinase 3 beta/metabolismo , Camundongos , Camundongos Knockout , Neurônios/patologia , PPAR gama/genética , Fosforilação , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Agregação Patológica de Proteínas/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo
20.
PLoS One ; 14(3): e0213521, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30913220

RESUMO

Huntington's disease (HD) is a monogenic neurodegenerative disorder caused by an expansion of the CAG trinucleotide repeat domain in the huntingtin (HTT) gene, leading to an expanded poly-glutamine (polyQ) stretch in the HTT protein. This mutant HTT (mHTT) protein is highly prone to intracellular aggregation, causing significant damage and cellular loss in the striatal, cortical, and other regions of the brain. Therefore, modulation of mHTT levels in these brain regions in order to reduce intracellular mHTT and aggregate levels represents a direct approach in the development of HD therapeutics. To this end, assays that can be used to detect changes in HTT levels in biological samples are invaluable tools to assess target engagement and guide dose selection in clinical trials. The Meso Scale Discovery (MSD) ELISA-based assay platform is a robust and sensitive method previously employed for the quantification of HTT. However, the currently available MSD assays for HTT are primarily detecting the monomeric soluble form of the protein, but not aggregated species. In this study, we describe the development of novel MSD assays preferentially detecting mHTT in an aggregated form. Recombinant monomeric HTT(1-97)-Q46, which forms aggregates in a time-dependent manner, was used to characterize the ability of each established assay to distinguish between HTT monomers and HTT in a higher assembly state. Further validation of these assays was performed using brain lysates from R6/2, zQ175 knock-in, and BACHD mouse models, to replicate a previously well-characterized age-dependent increase in brain aggregate signals, as well as a significant reduction of aggregate levels in the striatum following mHTT knockdown with a CAG-directed allele-specific zinc-finger repressor protein (ZFP). Lastly, size exclusion chromatography was used to separate and characterize HTT species from brain tissue lysates to demonstrate specificity of the assays for the fractions containing aggregated HTT. In summary, we demonstrate that the newly developed assays preferentially detect aggregated HTT with improved performance in comparison to previous assay technologies. These assays complement the existing MSD platform assays specific for soluble HTT monomers, allowing for a more comprehensive analysis of disease-relevant HTT species in preclinical models of HD.


Assuntos
Bioensaio , Encéfalo/metabolismo , Proteína Huntingtina/metabolismo , Doença de Huntington/metabolismo , Peptídeos/metabolismo , Agregação Patológica de Proteínas/metabolismo , Animais , Modelos Animais de Doenças , Humanos , Proteína Huntingtina/genética , Doença de Huntington/genética , Doença de Huntington/patologia , Camundongos , Camundongos Transgênicos , Peptídeos/genética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/patologia
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