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1.
Science ; 370(6512): 56-60, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33004511

RESUMO

Over the past decade, phase transitions have emerged as a fundamental mechanism of cellular organization. In parallel, a wealth of evidence has accrued indicating that aberrations in phase transitions are early events in the pathogenesis of several neurodegenerative diseases. We review the key evidence of defects at multiple levels, from phase transition of individual proteins to the dynamic behavior of complex, multicomponent condensates in neurodegeneration. We also highlight two concepts, dynamical arrest and heterotypic buffering, that are key to understanding how pathological phase transitions relate to pleiotropic defects in cellular functions and the accrual of proteinaceous deposits at end-stage disease. These insights not only illuminate disease etiology but also are likely to guide the development of therapeutic interventions to restore homeostasis.


Assuntos
Doenças Neurodegenerativas/metabolismo , Transição de Fase , Agregados Proteicos , Agregação Patológica de Proteínas/metabolismo , Animais , Modelos Animais de Doenças , Humanos
2.
PLoS One ; 15(9): e0239584, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966331

RESUMO

Familial forms of Alzheimer's disease (AD) are caused by mutations in the presenilin genes or in the gene encoding for the amyloid precursor protein (APP). Proteolytic cleavage of APP generates the ß-amyloid peptide (Aß), which aggregates into amyloid plaques, one of the major hallmarks of AD. APP mutations within the Aß sequence, so-called intra-Aß mutations, cluster around position E693 of APP, which corresponds to position E22 in the Aß sequence. One of these mutations is the Osaka mutation, E693Δ, which has unique aggregation properties with patients showing unusually low brain amyloid levels on amyloid PET scans. Despite intense research on the pathomechanisms of different intra-Aß mutants, our knowledge is limited due to controversial findings in various studies. Here, we investigated in an ex vivo experimental system the neuro- and synaptotoxic properties of two intra-Aß mutants with different intrinsic aggregation propensities, the Osaka mutation E22Δ and the Arctic mutation E22G, and compared them to wild-type (wt) Aß. Experiments in hippocampal slice cultures from transgenic mice were complemented by treating wild-type slices with recombinantly produced Aß40 or Aß42 containing the respective intra-Aß mutations. Our analyses revealed that wt Aß and E22G Aß, both recombinant and transgenic, caused a loss of dendritic spines along with an increase in tau phosphorylation and tau-dependent neurodegeneration. In all experiments, the 42-residue variants of wt and E22G Aß showed stronger effects than the respective Aß40 isoforms. In contrast, E22Δ Aß neither reduced dendritic spine density nor resulted in increased tau phosphorylation or neuronal cell death in our ex vivo system. Our findings suggest that the previously reported major differences in the aggregation kinetics between E22G and E22Δ Aß are likely reflected in different disease pathomechanisms.


Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/genética , Proteínas Mutantes/genética , Mutação , Proteínas tau/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Animais , Morte Celular , Espinhas Dendríticas/patologia , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Técnicas In Vitro , Cinética , Camundongos , Camundongos Transgênicos , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fosforilação , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sinapses/patologia
3.
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
4.
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
5.
PLoS One ; 15(8): e0237328, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790707

RESUMO

α-Synuclein (αSyn) fibrils spread from one neuronal cell to another. This prion-like phenomenon is believed to contribute to the progression of the pathology in Parkinson's disease and other synucleinopathies. The binding of αSyn fibrils originating from affected cells to the plasma membrane of naïve cells is key in their prion-like propagation propensity. To interfere with this process, we designed polypeptides derived from proteins we previously showed to interact with αSyn fibrils, namely the molecular chaperone Hsc70 and the sodium/potassium pump NaK-ATPase and assessed their capacity to bind αSyn fibrils and/or interfere with their take-up by cells of neuronal origin. We demonstrate here that polypeptides that coat αSyn fibrils surfaces in such a way that they are changed affect αSyn fibrils binding to the plasma membrane components and/or their take-up by cells. Altogether our observations suggest that the rationale design of αSyn fibrils polypeptide binders that interfere with their propagation between neuronal cells holds therapeutic potential.


Assuntos
Neurônios/efeitos dos fármacos , Peptídeos/farmacologia , Agregação Patológica de Proteínas/tratamento farmacológico , alfa-Sinucleína/metabolismo , Sequência de Aminoácidos , Amiloide/antagonistas & inibidores , Amiloide/metabolismo , Animais , Linhagem Celular , Proteínas de Choque Térmico HSC70/química , Proteínas de Choque Térmico HSC70/metabolismo , Proteínas de Choque Térmico HSC70/farmacologia , Humanos , Camundongos , Modelos Moleculares , Neurônios/metabolismo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Peptídeos/química , Príons/antagonistas & inibidores , Príons/metabolismo , Agregados Proteicos/efeitos dos fármacos , Agregação Patológica de Proteínas/metabolismo , ATPase Trocadora de Sódio-Potássio/química , ATPase Trocadora de Sódio-Potássio/metabolismo , ATPase Trocadora de Sódio-Potássio/farmacologia
6.
Proc Natl Acad Sci U S A ; 117(31): 18661-18669, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32675242

RESUMO

Huntington's disease (HD) is a progressive incurable neurodegenerative disorder characterized by motor and neuropsychiatric symptoms. It is caused by expansion of a cytosine-adenine-guanine triplet in the N-terminal domain of exon 1 in the huntingtin (HTT) gene that codes for an expanded polyglutamine stretch in the protein product which becomes aggregation prone. The mutant Htt (mHtt) aggregates are associated with components of the ubiquitin-proteasome system, suggesting that mHtt is marked for proteasomal degradation and that, for reasons still debated, are not properly degraded. We used a novel HD rat model, proteomic analysis, and long-term live neuronal imaging to characterize the effects of ubiquitination on aggregation of mHtt and subsequent cellular responses. We identified two lysine residues, 6 and 9, in the first exon of mHtt that are specifically ubiquitinated in striatal and cortical brain tissues of mHtt-transgenic animals. Expression of mHtt exon 1 lacking these ubiquitination sites in cortical neurons and cultured cells was found to slow aggregate appearance rates and reduce their size but at the same time increase the number of much smaller and less visible ones. Importantly, expression of this form of mHtt was associated with elevated death rates. Proteomic analysis indicated that cellular reactions to mHtt expression were weaker in cells expressing the lysineless protein, possibly implying a reduced capacity to cope with the proteotoxic stress. Taken together, the findings suggest a novel role for ubiquitination-attenuation of the pathogenic effect of mHtt.


Assuntos
Proteína Huntingtina , Doença de Huntington , Ubiquitinação/fisiologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Morte Celular/fisiologia , Células Cultivadas , Modelos Animais de Doenças , Humanos , Proteína Huntingtina/química , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/genética , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Lisina/química , Lisina/metabolismo , Neurônios/metabolismo , Complexo de Endopeptidases do Proteassoma , Agregação Patológica de Proteínas/metabolismo , Ratos , Ratos Transgênicos
7.
Nat Commun ; 11(1): 3281, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32612175

RESUMO

Amyloid fibrils result from the aggregation of host cell-encoded proteins, many giving rise to specific human illnesses such as Alzheimer's disease. Here we show that the major virulence factor of Rift Valley fever virus, the protein NSs, forms filamentous structures in the brain of mice and affects mortality. NSs assembles into nuclear and cytosolic disulfide bond-dependent fibrillary aggregates in infected cells. NSs structural arrangements exhibit characteristics typical for amyloids, such as an ultrastructure of 12 nm-width fibrils, a strong detergent resistance, and interactions with the amyloid-binding dye Thioflavin-S. The assembly dynamics of viral amyloid-like fibrils can be visualized in real-time. They form spontaneously and grow in an amyloid fashion within 5 hours. Together, our results demonstrate that viruses can encode amyloid-like fibril-forming proteins and have strong implications for future research on amyloid aggregation and toxicity in general.


Assuntos
Amiloide/metabolismo , Proteínas Amiloidogênicas/metabolismo , Febre do Vale de Rift/metabolismo , Vírus da Febre do Vale do Rift/metabolismo , Proteínas não Estruturais Virais/metabolismo , Amiloide/química , Amiloide/ultraestrutura , Proteínas Amiloidogênicas/química , Animais , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Núcleo Celular/virologia , Chlorocebus aethiops , Células HeLa , Humanos , Camundongos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Agregação Patológica de Proteínas/metabolismo , Febre do Vale de Rift/virologia , Vírus da Febre do Vale do Rift/patogenicidade , Células Vero , Proteínas não Estruturais Virais/química , Virulência , Fatores de Virulência
8.
PLoS Pathog ; 16(6): e1008611, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32511263

RESUMO

Human infection with avian influenza A (H5N1) and (H7N9) viruses causes severe respiratory diseases. PB1-F2 protein is a critical virulence factor that suppresses early type I interferon response, but the mechanism of its action in relation to high pathogenicity is not well understood. Here we show that PB1-F2 protein of H7N9 virus is a particularly potent suppressor of antiviral signaling through formation of protein aggregates on mitochondria and inhibition of TRIM31-MAVS interaction, leading to prevention of K63-polyubiquitination and aggregation of MAVS. Unaggregated MAVS accumulated on fragmented mitochondria is prone to degradation by both proteasomal and lysosomal pathways. These properties are proprietary to PB1-F2 of H7N9 virus but not shared by its counterpart in WSN virus. A recombinant virus deficient of PB1-F2 of H7N9 induces more interferon ß in infected cells. Our findings reveal a subtype-specific mechanism for destabilization of MAVS and suppression of interferon response by PB1-F2 of H7N9 virus.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Subtipo H7N9 do Vírus da Influenza A/metabolismo , Influenza Humana/metabolismo , Agregação Patológica de Proteínas/metabolismo , Transdução de Sinais , Proteínas Virais/metabolismo , Células A549 , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Cães , Células HEK293 , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Humana/genética , Influenza Humana/patologia , Interferon beta/genética , Interferon beta/metabolismo , Células Madin Darby de Rim Canino , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Agregação Patológica de Proteínas/genética , Células THP-1 , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Virais/genética
9.
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
10.
Biochim Biophys Acta Proteins Proteom ; 1868(9): 140446, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32442520

RESUMO

α-Crystallin, comprising 40-50 subunits of αA- and αB-subunits, is a long-lived major soluble chaperone protein in lens. During aging, α-crystallin forms aggregates of high molecular weight (HMW) protein and eventually becomes water-insoluble (WI). Isomerization of Asp in α-crystallin has been proposed as a trigger of protein aggregation, ultimately leading to cataract formation. Here, we have investigated the relationship between protein aggregation and Asp isomerization of αA-crystallin by a series of analyses of the soluble α-crystallin, HMW and WI fractions from human lens samples of different ages (10-76 years). Analytical ultracentrifugation showed that the HMW fraction had a peak sedimentation coefficient of 40 S and a wide distribution of values (10-450 S) for lens of all ages, whereas the α-crystallin had a much smaller peak sedimentation coefficient (10-20 S) and was less heterogeneous, regardless of lens age. Measurement of the ratio of isomers (Lα-, Lß-, Dα-, Dß-) at Asp58, Asp91/92 and Asp151 in αA-crystallin by liquid chromatography-mass spectrometry showed that the proportion of isomers at all three sites increased in order of aggregation level (α-crystallin < HMW < WI fractions). Among the abnormal isomers of Asp58 and Asp151, Dß-isomers were predominant with a very few exceptions. Notably, the chaperone activity of HMW protein was minimal for lens of all ages, whereas that of α-crystallin decreased with increasing lens age. Thus, abnormal aggregation caused by Asp isomerization might contribute to the loss of chaperone activity of α-crystallin in aged human lens.


Assuntos
Catarata/metabolismo , Cristalino/química , Agregação Patológica de Proteínas/metabolismo , alfa-Cristalinas/química , Adolescente , Adulto , Idoso , Envelhecimento/metabolismo , Criança , Cromatografia Líquida de Alta Pressão , Cristalinas , Humanos , Isomerismo , Cristalino/metabolismo , Espectrometria de Massas , Pessoa de Meia-Idade , Peso Molecular , Adulto Jovem , alfa-Cristalinas/metabolismo
11.
Sci Rep ; 10(1): 4023, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32132570

RESUMO

The Alzheimer's disease pathology is associated with accumulation of intracellular neurofibrillary tangles and extracellular senile plaques. The formation of initial nucleus triggers conformational changes in Tau and leads to its deposition. Hence, there is a need to eliminate these toxic proteins for proper functioning of neuronal cells. In this aspect, we screened the effect of basic limonoids such as gedunin, epoxyazadiradione, azadirone and azadiradione on inhibiting Tau aggregation as well as disintegration of induced Tau aggregates. It was observed that these basic limonoids effectively prevented aggregates formation by Tau and also exhibited the property of destabilizing matured Tau aggregates. The molecular docking analysis suggests that the basic limonoids interact with hexapeptide regions of aggregated Tau. Although these limonoids caused the conformational changes in Tau to ß-sheet structure, the cytological studies indicate that basic limonoids rescued cell death. The dual role of limonoids in Tau aggregation inhibition and disintegration of matured aggregates suggests them to be potent molecules in overcoming Tau pathology. Further, their origin from a medicinally important plant neem, which known to possess remarkable biological activities was also found to play protective role in HEK293T cells. Basic limonoids were non-toxic to HEK293T cells and also aided in activation of HSF1 by inducing its accumulation in nucleus. Western blotting and immunofluorescence studies showed that HSF1 in downstream increased the transcription of Hsp70 thus, aggravating cytosolic Hsp70 levels that can channel clearance of aberrant Tau. All these results mark basic limonoids as potential therapeutic natural products.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Limoninas , Simulação de Acoplamento Molecular , Agregação Patológica de Proteínas/metabolismo , Proteostase/efeitos dos fármacos , Proteínas tau , Células HEK293 , Fatores de Transcrição de Choque Térmico/metabolismo , Humanos , Limoninas/química , Limoninas/farmacologia , Proteínas tau/química , Proteínas tau/metabolismo
12.
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
13.
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
14.
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
15.
Nat Commun ; 11(1): 1004, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081878

RESUMO

Cytoplasmic aggregation of TDP-43 characterizes degenerating neurons in most cases of amyotrophic lateral sclerosis (ALS). Here, we develop an optogenetic TDP-43 variant (opTDP-43), whose multimerization status can be modulated in vivo through external light illumination. Using the translucent zebrafish neuromuscular system, we demonstrate that short-term light stimulation reversibly induces cytoplasmic opTDP-43 mislocalization, but not aggregation, in the spinal motor neuron, leading to an axon outgrowth defect associated with myofiber denervation. In contrast, opTDP-43 forms pathological aggregates in the cytoplasm after longer-term illumination and seeds non-optogenetic TDP-43 aggregation. Furthermore, we find that an ALS-linked mutation in the intrinsically disordered region (IDR) exacerbates the light-dependent opTDP-43 toxicity on locomotor behavior. Together, our results propose that IDR-mediated TDP-43 oligomerization triggers both acute and long-term pathologies of motor neurons, which may be relevant to the pathogenesis and progression of ALS.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Medula Espinal/metabolismo , Medula Espinal/patologia , Esclerose Amiotrófica Lateral/genética , Animais , Animais Geneticamente Modificados , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Humanos , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Modelos Moleculares , Mutação , Optogenética , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Multimerização Proteica , Estabilidade Proteica , Regulação para Cima , Peixe-Zebra
16.
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
17.
Biochem Biophys Res Commun ; 524(2): 453-458, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32007272

RESUMO

In most cases high cytotoxicity is characteristic of aggregates formed during lag phase of amyloid formation, whereas mature fibrils represent the depot of protein molecules incapable of damaging cell membranes. However, new experimental data show that in cases of some proteins the fibrils are the most toxic type of aggregates. Meanwhile, structural characteristics of cytotoxic fibrils and mechanisms of their cell damaging action are insufficiently explored. This work is dedicated to studying amyloid aggregation of bovine carbonic anhydrase (BCA) and effect of aggregates formed at different stages of amyloid formation on viability of the cells. Here we demonstrate that oligomers formed during lag phase do not decrease cell viability, whereas protofibrils and amyloids of BCA are cytotoxic. Obtained results allow concluding that toxicity of BCA aggregates is associated with the presence of amyloid cross-ß-structure, which signature is absorbance peak at low wavenumbers at FTIR spectra (1615-1630 cm-1). Our data suppose that cross-ß-core of ВСА amyloid fibrils is responsible for their cytotoxicity.


Assuntos
Amiloide/metabolismo , Anidrase Carbônica II/metabolismo , Agregação Patológica de Proteínas/metabolismo , Amiloide/química , Amiloide/ultraestrutura , Animais , Anidrase Carbônica II/química , Bovinos , Linhagem Celular , Sobrevivência Celular , Agregados Proteicos , Conformação Proteica em Folha beta
18.
Biochem Biophys Res Commun ; 524(2): 446-452, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32007275

RESUMO

The cMyb trans-activation domain is one of the model systems to understand the folding and binding mechanisms in intrinsically disordered proteins. cMyb (291-315) TAD (cMyb TAD) upon interaction with KIX plays a crucial role in transcriptional regulation. However, nothing is known regarding its aggregation behaviour on change of buffer conditions or stressed environment. Notably, most of the disease-associated amyloid-forming proteins such as Aß, Tau, α-synuclein, and amylin are natively unstructured. Nevertheless, to date, very fewer evidence on aggregation behaviours on TAD domains are available. Therefore, this is necessary to investigate the aggregation propensity of intrinsically disordered cMyb TAD domain in isolation. As an essential step in that direction, we have extensively studied the aggregation behaviour of cMyb TAD using the standard approaches for aggregation studies and systematically probed the amyloid conformations. These aggregates are ThT and ANS-positive whose amyloid nature was also confirmed by Far-UV CD spectroscopic studies suggesting that cMyb TAD fibrils are rich in ß-sheet secondary structure, transmission electron microscopy revealed the formation of characteristic long branched amyloid fibrils of 6-16 nm diameter, and MTT assay in SH-SY5Y neuroblastoma cells suggest that these aggregates are cytotoxic. This amyloid nature of cMyb TAD may affect its binding with KIX and alter cMyb function (transcriptional regulation) under acidic/stressed conditions.


Assuntos
Amiloide/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Agregação Patológica de Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-myb/metabolismo , Amiloide/química , Linhagem Celular , Humanos , Proteínas Intrinsicamente Desordenadas/química , Agregados Proteicos , Conformação Proteica em Folha beta , Domínios Proteicos , Dobramento de Proteína , Proteínas Proto-Oncogênicas c-myb/química
19.
Biochim Biophys Acta Gen Subj ; 1864(5): 129557, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32045632

RESUMO

BACKGROUND: Polyamines can induce protein aggregation that can be related to the physiology of the cellular function. Polyamines have been implicated in protein aggregation which may lead to neuropathic and non neuropathic amyloidosis. SCOPE OF REVIEW: Change in the level of polyamine concentration has been associated with ageing and neurodegeneration such as Parkinson's disease, Alzheimer's disease. Lysozyme aggregation in the presence of polyamines leads to non neuropathic amyloidosis. Polyamine analogues can suppress or inhibit protein aggregation suggesting their efficacy against amyloidogenic protein aggregates. MAJOR CONCLUSIONS: In this study we report the comparative interactions of lysozyme with the polyamine analogue, 1-naphthyl acetyl spermine in comparison with the biogenic polyamines through spectroscopy, calorimetry, imaging and docking techniques. The findings revealed that the affinity of binding varied as spermidine > 1-naphthyl acetyl spermine > spermine. The biogenic polyamines accelerated the rate of fibrillation significantly, whereas the analogue inhibited the rate of fibrillation to a considerable extent. The polyamines bind near the catalytic diad residues viz. Glu35 and Asp52, and in close proximity of Trp62 residue. However, the analogue showed dual nature of interaction where its alkyl amine region bind in same way as the biogenic polyamines bind to the catalytic site, while the naphthyl group makes hydrophobic contacts with Trp62 and Trp63, thereby suggesting its direct influence on fibrillation. GENERAL SIGNIFICANCE: This study, thus, potentiates, the development of a polyamine analogue that can perform as an effective inhibitor targeted towards aggregation of amyloidogenic proteins.


Assuntos
Amiloide/metabolismo , Proteínas Aviárias/metabolismo , Galinhas/metabolismo , Muramidase/metabolismo , Espermidina/metabolismo , Espermina/análogos & derivados , Amiloidose/metabolismo , Animais , Poliaminas Biogênicas/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Agregados Proteicos , Agregação Patológica de Proteínas/metabolismo , Espermina/metabolismo
20.
Mol Cell Biochem ; 466(1-2): 117-128, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32056106

RESUMO

Aberrant structural formations of Cu/Zn superoxide dismutase enzyme (SOD1) are the probable mechanism by which circumscribed mutations in the SOD1 gene cause familial amyotrophic lateral sclerosis (ALS1). SOD1 forms aberrant structures which can proceed by nucleation to insoluble aggregates. Here, the SOD1 aggregation reaction was investigated predominantly by time-course studies on ALS1 variants G85R, G37R, D101G, and D101N in human embryonic kidney cells (HEK293FT), with analysis by detergent ultracentrifugation extractions and high-resolution PAGE methodologies. Nucleation was found to be pseudo-zeroth order and dependent on time and concentration at constant 37.0 °C and pH 7.4. The predominant subsets of the total SOD1 expression set which comprised the nucleation phase were both soluble and insoluble inactive monomers, trimers, and hexamers with reduced intra-disulfide bonds. Superoxide exposure via paraquat initiated the formation of SOD1 trimers in untransfected SH-SY5Y cells and increased the aggregation propensity of G85R in HEK293FT. These data show the kinetic formation of aberrant SOD1 subsets implicated in ALS1 and indicate that superoxide substrate may initiate its radical polymerization. In an instance of the utility of methodological reductionism in molecular theory: though many ALS1 variants retain their global enzymatic activity, the SOD1 subsets most implicated in causing ALS1 do not retain their specific activity.


Assuntos
Mutação de Sentido Incorreto , Agregação Patológica de Proteínas/metabolismo , Superóxido Dismutase-1/metabolismo , Substituição de Aminoácidos , Esclerose Amiotrófica Lateral/genética , Animais , Linhagem Celular Tumoral , Células HEK293 , Humanos , Camundongos , Células NIH 3T3 , Agregação Patológica de Proteínas/genética , Superóxido Dismutase-1/química , Superóxido Dismutase-1/genética
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