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1.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200180

RESUMO

Tauopathies are a heterogeneous class of neurodegenerative diseases characterized by intracellular inclusions of aggregated tau proteins. Tau aggregates in different tauopathies have distinct structural features and can be found in different cell types. Transgenic animal models overexpressing human tau have been used for over two decades in the research of tau pathology. However, these models poorly recapitulate the heterogeneity of tauopathies found in human brains. Recent findings demonstrate that injection of purified tau aggregates from the brains of human tauopathy patients recapitulates both the structural features and cell-type specificity of the tau pathology of the donor tauopathy. These models may therefore have unique translational value in the study of functional consequences of tau pathology, tau-based diagnostics, and tau targeting therapeutics. This review provides an update of the literature relating to seeding-based tauopathy and their potential applications.


Assuntos
Doença de Alzheimer/patologia , Encéfalo/patologia , Modelos Animais de Doenças , Agregados Proteicos , Tauopatias/patologia , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Animais , Encéfalo/metabolismo , Humanos , Camundongos , Tauopatias/metabolismo , Proteínas tau/química
2.
Int J Mol Sci ; 22(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202166

RESUMO

Copper (Cu) has been implicated in the progression of Alzheimer's disease (AD), and aggregation of Cu and amyloid ß peptide (Aß) are considered key pathological features of AD. Metal chelators are considered to be potential therapeutic agents for AD because of their capacity to reduce metal ion-induced Aß aggregation through the regulation of metal ion distribution. Here, we used phage display technology to screen, synthesize, and evaluate a novel Cu(II)-binding peptide that specifically blocked Cu-triggered Aß aggregation. The Cu(II)-binding peptide (S-A-Q-I-A-P-H, PCu) identified from the phage display heptapeptide library was used to explore the mechanism of PCu inhibition of Cu2+-mediated Aß aggregation and Aß production. In vitro experiments revealed that PCu directly inhibited Cu2+-mediated Aß aggregation and regulated copper levels to reduce biological toxicity. Furthermore, PCu reduced the production of Aß by inhibiting Cu2+-induced BACE1 expression and improving Cu(II)-mediated cell oxidative damage. Cell culture experiments further demonstrated that PCu had relatively low toxicity. This Cu(II)-binding peptide that we have identified using phage display technology provides a potential therapeutic approach to prevent or treat AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Proteínas de Transporte/metabolismo , Cobre/metabolismo , Peptídeos/metabolismo , Agregados Proteicos , Mapeamento de Interação de Proteínas , Sequência de Aminoácidos , Peptídeos beta-Amiloides/química , Animais , Proteínas de Transporte/química , Técnicas de Visualização da Superfície Celular , Humanos , Camundongos , Oxirredução , Estresse Oxidativo , Peptídeos/química , Agregação Patológica de Proteínas/metabolismo , Mapeamento de Interação de Proteínas/métodos
3.
Molecules ; 26(12)2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34205516

RESUMO

Neurodegenerative disorders, including Tauopathies that involve tau protein, base their pathological mechanism on forming proteinaceous aggregates, which has a deleterious effect on cells triggering an inflammatory response. Moreover, tau inhibitors can exert their mechanism of action through noncovalent and covalent interactions. Thus, Michael's addition appears as a feasible type of interaction involving an α, ß unsaturated carbonyl moiety to avoid pathological confirmation and further cytotoxicity. Moreover, we isolated three compounds from Antarctic lichens Cladonia cariosa and Himantormia lugubris: protolichesterinic acid (1), fumarprotocetraric acid (2), and lichesterinic acid (3). The maleimide cysteine labeling assay showed that compounds 1, 2, and 3 inhibit at 50 µM, but compounds 2 and 3 are statistically significant. Based on its inhibition capacity, we decided to test compound 2 further. Thus, our results suggest that compound 2 remodel soluble oligomers and diminish ß sheet content, as demonstrated through ThT experiments. Hence, we added externally treated oligomers with compound 2 to demonstrate that they are harmless in cell culture. First, the morphology of cells in the presence of aggregates does not suffer evident changes compared to the control. Additionally, the externally added aggregates do not provoke a substantial LDH release compared to the control, indicating that treated oligomers do not provoke membrane damage in cell culture compared with aggregates alone. Thus, in the present work, we demonstrated that Michael's acceptors found in lichens could serve as a scaffold to explore different mechanisms of action to turn tau aggregates into harmless species.


Assuntos
Fumaratos/farmacologia , Agregados Proteicos/efeitos dos fármacos , Proteínas tau/antagonistas & inibidores , Proteínas tau/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/farmacologia , Regiões Antárticas , Ascomicetos/metabolismo , Linhagem Celular Tumoral , Humanos , Líquens/metabolismo , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/metabolismo , Parmeliaceae/metabolismo , Tauopatias/tratamento farmacológico , Tauopatias/metabolismo
4.
Int J Mol Sci ; 22(12)2021 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-34199295

RESUMO

Spinocerebellar ataxia type 3 (SCA3), a hereditary and lethal neurodegenerative disease, is attributed to the abnormal accumulation of undegradable polyglutamine (polyQ), which is encoded by mutated ataxin-3 gene (ATXN3). The toxic fragments processed from mutant ATXN3 can induce neuronal death, leading to the muscular incoordination of the human body. Some treatment strategies of SCA3 are preferentially focused on depleting the abnormal aggregates, which led to the discovery of small molecule n-butylidenephthalide (n-BP). n-BP-promoted autophagy protected the loss of Purkinje cell in the cerebellum that regulates the network associated with motor functions. We report that the n-BP treatment may be effective in treating SCA3 disease. n-BP treatment led to the depletion of mutant ATXN3 with the expanded polyQ chain and the toxic fragments resulting in increased metabolic activity and alleviated atrophy of SCA3 murine cerebellum. Furthermore, n-BP treated animal and HEK-293GFP-ATXN3-84Q cell models could consistently show the depletion of aggregates through mTOR inhibition. With its unique mechanism, the two autophagic inhibitors Bafilomycin A1 and wortmannin could halt the n-BP-induced elimination of aggregates. Collectively, n-BP shows promising results for the treatment of SCA3.


Assuntos
Autofagia , Doença de Machado-Joseph/tratamento farmacológico , Doença de Machado-Joseph/patologia , Anidridos Ftálicos/uso terapêutico , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Adenilato Quinase/metabolismo , Animais , Ataxina-3/genética , Autofagia/efeitos dos fármacos , Cerebelo/patologia , Feminino , Células HEK293 , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Doença de Machado-Joseph/fisiopatologia , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Mutação/genética , Anidridos Ftálicos/farmacologia , Agregados Proteicos/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/patologia , Transdução de Sinais/efeitos dos fármacos
5.
Molecules ; 26(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199487

RESUMO

Phenolic compounds are thought to be important to prevent neurodegenerative diseases (ND). Parkinson's Disease (PD) is a neurodegenerative disorder known for its typical motor features, the deposition of α-synuclein (αsyn)-positive inclusions in the brain, and for concomitant cellular pathologies that include oxidative stress and neuroinflammation. Neuroprotective activity of fisetin, a dietary flavonoid, was evaluated against main hallmarks of PD in relevant cellular models. At physiologically relevant concentrations, fisetin protected SH-SY5Y cells against oxidative stress overtaken by tert-butyl hydroperoxide (t-BHP) and against methyl-4-phenylpyridinuim (MPP+)-induced toxicity in dopaminergic neurons, the differentiated Lund human Mesencephalic (LUHMES) cells. In this cellular model, fisetin promotes the increase of the levels of dopamine transporter. Remarkably, fisetin reduced the percentage of cells containing αsyn inclusions as well as their size and subcellular localization in a yeast model of αsyn aggregation. Overall, our data show that fisetin exerts modulatory activities toward common cellular pathologies present in PD; remarkably, it modulates αsyn aggregation, supporting the idea that diets rich in this compound may prove beneficial.


Assuntos
Butiratos/efeitos adversos , Flavonóis/farmacologia , Doença de Parkinson/metabolismo , Piperidinas/efeitos adversos , alfa-Sinucleína/metabolismo , Linhagem Celular , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Humanos , Modelos Biológicos , Estresse Oxidativo , Doença de Parkinson/tratamento farmacológico , Agregados Proteicos/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , terc-Butil Hidroperóxido/metabolismo
6.
Int J Mol Sci ; 22(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199513

RESUMO

Intrinsic disorder is a natural feature of polypeptide chains, resulting in the lack of a defined three-dimensional structure. Conformational changes in intrinsically disordered regions of a protein lead to unstable ß-sheet enriched intermediates, which are stabilized by intermolecular interactions with other ß-sheet enriched molecules, producing stable proteinaceous aggregates. Upon misfolding, several pathways may be undertaken depending on the composition of the amino acidic string and the surrounding environment, leading to different structures. Accumulating evidence is suggesting that the conformational state of a protein may initiate signalling pathways involved both in pathology and physiology. In this review, we will summarize the heterogeneity of structures that are produced from intrinsically disordered protein domains and highlight the routes that lead to the formation of physiological liquid droplets as well as pathogenic aggregates. The most common proteins found in aggregates in neurodegenerative diseases and their structural variability will be addressed. We will further evaluate the clinical relevance and future applications of the study of the structural heterogeneity of protein aggregates, which may aid the understanding of the phenotypic diversity observed in neurodegenerative disorders.


Assuntos
Doenças Neurodegenerativas/genética , Agregados Proteicos/genética , Agregação Patológica de Proteínas/genética , Conformação Proteica em Folha beta , Amiloide/genética , Amiloide/ultraestrutura , Humanos , Proteínas Intrinsicamente Desordenadas , Doenças Neurodegenerativas/patologia , alfa-Sinucleína/genética , alfa-Sinucleína/ultraestrutura , Proteínas tau/genética , Proteínas tau/ultraestrutura
7.
Int J Mol Sci ; 22(12)2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208575

RESUMO

Due to their high specificity, monoclonal antibodies have been widely investigated for their application in drug delivery to the central nervous system (CNS) for the treatment of neurological diseases such as stroke, Alzheimer's, and Parkinson's disease. Research in the past few decades has revealed that one of the biggest challenges in the development of antibodies for drug delivery to the CNS is the presence of blood-brain barrier (BBB), which acts to restrict drug delivery and contributes to the limited uptake (0.1-0.2% of injected dose) of circulating antibodies into the brain. This article reviews the various methods currently used for antibody delivery to the CNS at the preclinical stage of development and the underlying mechanisms of BBB penetration. It also describes efforts to improve or modulate the physicochemical and biochemical properties of antibodies (e.g., charge, Fc receptor binding affinity, and target affinity), to adapt their pharmacokinetics (PK), and to influence their distribution and disposition into the brain. Finally, a distinction is made between approaches that seek to modify BBB permeability and those that use a physiological approach or antibody engineering to increase uptake in the CNS. Although there are currently inherent difficulties in developing safe and efficacious antibodies that will cross the BBB, the future prospects of brain-targeted delivery of antibody-based agents are believed to be excellent.


Assuntos
Anticorpos Monoclonais/metabolismo , Anticorpos/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Animais , Anticorpos/administração & dosagem , Anticorpos/efeitos adversos , Anticorpos/uso terapêutico , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/uso terapêutico , Transporte Biológico , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Encéfalo/efeitos dos fármacos , Vias de Administração de Medicamentos , Humanos , Imunoconjugados/administração & dosagem , Imunoconjugados/efeitos adversos , Imunoconjugados/metabolismo , Imunoconjugados/uso terapêutico , Permeabilidade , Agregados Proteicos , Agregação Patológica de Proteínas , Engenharia de Proteínas , Distribuição Tecidual
8.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207662

RESUMO

p62/Sequestosome-1 (p62) is a multifunctional adaptor protein and is also a constant component of disease-associated protein aggregates, including Mallory-Denk bodies (MDBs), in steatohepatitis and hepatocellular carcinoma. We investigated the interaction of the two human p62 isoforms, p62-H1 (full-length isoform) and p62-H2 (partly devoid of PB1 domain), with keratins 8 and 18, the major components of MDBs. In human liver, p62-H2 is expressed two-fold higher compared to p62-H1 at the mRNA level and is present in slightly but not significantly higher concentrations at the protein level. Co-transfection studies in CHO-K1 cells, PLC/PRF/5 cells as well as p62- total-knockout and wild-type mouse fibroblasts revealed marked differences in the cytoplasmic distribution and aggregation behavior of the two p62 isoforms. Transfection-induced overexpression of p62-H2 generated large cytoplasmic aggregates in PLC/PRF/5 and CHO-K1 cells that mostly co-localized with transfected keratins resembling MDBs or (transfection without keratins) intracytoplasmic hyaline bodies. In fibroblasts, however, transfected p62-H2 was predominantly diffusely distributed in the cytoplasm. Aggregation of p62-H2 and p62ΔSH2 as well as the interaction with K8 (but not with K18) involves acquisition of cross-ß-sheet conformation as revealed by staining with luminescent conjugated oligothiophenes. These results indicate the importance of considering p62 isoforms in protein aggregation disease.


Assuntos
Queratinas/metabolismo , Agregados Proteicos , Proteína Sequestossoma-1/metabolismo , Animais , Células CHO , Cricetulus , Humanos , Queratinas/genética , Camundongos , Camundongos Knockout , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteína Sequestossoma-1/genética
9.
Int J Mol Sci ; 22(13)2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34209175

RESUMO

Apolipoprotein E (ApoE) isoforms exert intricate effects on cellular physiology beyond lipid transport and metabolism. ApoEs influence the onset of Alzheimer's disease (AD) in an isoform-dependent manner: ApoE4 increases AD risk, while ApoE2 decreases it. Previously we demonstrated that syndecans, a transmembrane proteoglycan family with increased expression in AD, trigger the aggregation and modulate the cellular uptake of amyloid beta (Aß). Utilizing our previously established syndecan-overexpressing cellular assays, we now explore how the interplay of ApoEs with syndecans contributes to key events, namely uptake and aggregation, in Aß pathology. The interaction of ApoEs with syndecans indicates isoform-specific characteristics arising beyond the frequently studied ApoE-heparan sulfate interactions. Syndecans, and among them the neuronal syndecan-3, increased the cellular uptake of ApoEs, especially ApoE2 and ApoE3, while ApoEs exerted opposing effects on syndecan-3-mediated Aß uptake and aggregation. ApoE2 increased the cellular internalization of monomeric Aß, hence preventing its extracellular aggregation, while ApoE4 decreased it, thus helping the buildup of extracellular plaques. The contrary effects of ApoE2 and ApoE4 remained once Aß aggregated: while ApoE2 reduced the uptake of Aß aggregates, ApoE4 facilitated it. Fibrillation studies also revealed ApoE4's tendency to form fibrillar aggregates. Our results uncover yet unknown details of ApoE cellular biology and deepen our molecular understanding of the ApoE-dependent mechanism of Aß pathology.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Apolipoproteína E2/metabolismo , Apolipoproteína E4/metabolismo , Apolipoproteínas E/metabolismo , Agregados Proteicos , Sindecana-3/metabolismo , Linhagem Celular Tumoral , Humanos , Isoformas de Proteínas
10.
Nat Commun ; 12(1): 3396, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099711

RESUMO

Amyotrophic lateral sclerosis and frontotemporal dementia are two neurodegenerative diseases with overlapping clinical features and the pathological hallmark of cytoplasmic deposits of misfolded proteins. The most frequent cause of familial forms of these diseases is a hexanucleotide repeat expansion in the non-coding region of the C9ORF72 gene that is translated into dipeptide repeat polymers. Here we show that proline/arginine repeat polymers derail protein folding by sequestering molecular chaperones. We demonstrate that proline/arginine repeat polymers inhibit the folding catalyst activity of PPIA, an abundant molecular chaperone and prolyl isomerase in the brain that is altered in amyotrophic lateral sclerosis. NMR spectroscopy reveals that proline/arginine repeat polymers bind to the active site of PPIA. X-ray crystallography determines the atomic structure of a proline/arginine repeat polymer in complex with the prolyl isomerase and defines the molecular basis for the specificity of disease-associated proline/arginine polymer interactions. The combined data establish a toxic mechanism that is specific for proline/arginine dipeptide repeat polymers and leads to derailed protein homeostasis in C9orf72-associated neurodegenerative diseases.


Assuntos
Esclerose Amiotrófica Lateral/patologia , Proteína C9orf72/genética , Dipeptídeos/metabolismo , Demência Frontotemporal/patologia , Peptidilprolil Isomerase/metabolismo , Esclerose Amiotrófica Lateral/genética , Arginina/genética , Arginina/metabolismo , Biopolímeros/metabolismo , Encéfalo/patologia , Domínio Catalítico , Cristalografia por Raios X , Expansão das Repetições de DNA , Dipeptídeos/genética , Demência Frontotemporal/genética , Humanos , Ressonância Magnética Nuclear Biomolecular , Peptidilprolil Isomerase/isolamento & purificação , Peptidilprolil Isomerase/ultraestrutura , Prolina/genética , Prolina/metabolismo , Agregados Proteicos/genética , Ligação Proteica , Dobramento de Proteína , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Sequências Repetitivas de Aminoácidos/genética
11.
J Cell Sci ; 134(11)2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34085697

RESUMO

The toxic metalloid arsenic causes widespread misfolding and aggregation of cellular proteins. How these protein aggregates are formed in vivo, the mechanisms by which they affect cells and how cells prevent their accumulation is not fully understood. To find components involved in these processes, we performed a genome-wide imaging screen and identified Saccharomyces cerevisiae deletion mutants with either enhanced or reduced protein aggregation levels during arsenite exposure. We show that many of the identified factors are crucial to safeguard protein homeostasis (proteostasis) and to protect cells against arsenite toxicity. The hits were enriched for various functions including protein biosynthesis and transcription, and dedicated follow-up experiments highlight the importance of accurate transcriptional and translational control for mitigating protein aggregation and toxicity during arsenite stress. Some of the hits are associated with pathological conditions, suggesting that arsenite-induced protein aggregation may affect disease processes. The broad network of cellular systems that impinge on proteostasis during arsenic stress identified in this current study provides a valuable resource and a framework for further elucidation of the mechanistic details of metalloid toxicity and pathogenesis. This article has an associated First Person interview with the first authors of the paper.


Assuntos
Arsênio , Arsenitos , Proteínas de Saccharomyces cerevisiae , Arsenitos/toxicidade , Agregados Proteicos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
12.
Nat Commun ; 12(1): 3493, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34108467

RESUMO

In brown adipose tissue, thermogenesis is suppressed by thioesterase superfamily member 1 (Them1), a long chain fatty acyl-CoA thioesterase. Them1 is highly upregulated by cold ambient temperature, where it reduces fatty acid availability and limits thermogenesis. Here, we show that Them1 regulates metabolism by undergoing conformational changes in response to ß-adrenergic stimulation that alter Them1 intracellular distribution. Them1 forms metabolically active puncta near lipid droplets and mitochondria. Upon stimulation, Them1 is phosphorylated at the N-terminus, inhibiting puncta formation and activity and resulting in a diffuse intracellular localization. We show by correlative light and electron microscopy that Them1 puncta are biomolecular condensates that are inhibited by phosphorylation. Thus, Them1 forms intracellular biomolecular condensates that limit fatty acid oxidation and suppress thermogenesis. During a period of energy demand, the condensates are disrupted by phosphorylation to allow for maximal thermogenesis. The stimulus-coupled reorganization of Them1 provides fine-tuning of thermogenesis and energy expenditure.


Assuntos
Metabolismo Energético , Palmitoil-CoA Hidrolase/metabolismo , Tecido Adiposo Marrom/metabolismo , Agonistas Adrenérgicos/farmacologia , Sequência de Aminoácidos , Animais , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos/metabolismo , Espaço Intracelular/metabolismo , Gotículas Lipídicas/metabolismo , Camundongos , Mitocôndrias/metabolismo , Oxirredução , Palmitoil-CoA Hidrolase/química , Palmitoil-CoA Hidrolase/genética , Fosforilação/efeitos dos fármacos , Agregados Proteicos , Serina/metabolismo , Termogênese/efeitos dos fármacos
13.
J Phys Chem B ; 125(23): 6068-6079, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-34080429

RESUMO

Investigation of protein self-assembly processes is important for understanding the growth processes of functional proteins as well as disease-causing amyloids. Inside cells, intrinsic molecular fluctuations are so high that they cast doubt on the validity of the deterministic rate-equation approach. Furthermore, the protein environments inside cells are often crowded with other macromolecules, with volume fractions of the crowders as high as 40%. We have developed a stochastic kinetic framework using Gillespie's algorithm for general systems undergoing particle self-assembly, including particularly protein aggregation at the cellular level. The effects of macromolecular crowding are investigated using models built on scaled-particle and transition-state theories. The stochastic kinetic method can be formulated to provide information on the dominating aggregation mechanisms in a method called reaction frequency (or propensity) analysis. This method reveals that the change of scaling laws related to the lag time can be directly related to the change in the frequencies of reaction mechanisms. Further examination of the time evolution of the fibril mass and length quantities unveils that maximal fluctuations occur in the periods of rapid fibril growth and the fluctuations of both quantities can be sensitive functions of rate constants. The presence of crowders often amplifies the roles of primary and secondary nucleation and causes shifting in the relative importance of elongation, shrinking, fragmentation, and coagulation of linear aggregates. We also show a dual effect of changing volume on the halftime of aggregation for ApoC2 which is reduced in the presence of crowders. A comparison of the results of stochastic simulations with those of rate equations gives us information on the convergence relation between them and how the roles of reaction mechanisms change as the system volume is varied.


Assuntos
Amiloide , Agregados Proteicos , Algoritmos , Cinética , Substâncias Macromoleculares , Processos Estocásticos
14.
Int J Mol Sci ; 22(10)2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34067963

RESUMO

The effects that solid-liquid interfaces exert on the aggregation of proteins and peptides are of high relevance for various fields of basic and applied research, ranging from molecular biology and biomedicine to nanotechnology. While the influence of surface chemistry has received a lot of attention in this context, the role of surface topography has mostly been neglected so far. In this work, therefore, we investigate the aggregation of the type 2 diabetes-associated peptide hormone hIAPP in contact with flat and nanopatterned silicon oxide surfaces. The nanopatterned surfaces are produced by ion beam irradiation, resulting in well-defined anisotropic ripple patterns with heights and periodicities of about 1.5 and 30 nm, respectively. Using time-lapse atomic force microscopy, the morphology of the hIAPP aggregates is characterized quantitatively. Aggregation results in both amorphous aggregates and amyloid fibrils, with the presence of the nanopatterns leading to retarded fibrillization and stronger amorphous aggregation. This is attributed to structural differences in the amorphous aggregates formed at the nanopatterned surface, which result in a lower propensity for nucleating amyloid fibrillization. Our results demonstrate that nanoscale surface topography may modulate peptide and protein aggregation pathways in complex and intricate ways.


Assuntos
Agonistas dos Receptores da Amilina/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Nanoestruturas/química , Agregados Proteicos , Humanos , Modelos Moleculares , Propriedades de Superfície
15.
Aging (Albany NY) ; 13(11): 15620-15637, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34106880

RESUMO

Amyloid ß (Aß) plays a major role in the neurodegeneration of Alzheimer's disease (AD). The accumulation of misfolded Aß causes oxidative stress and inflammatory damage leading to apoptotic cell death. Traditional Chinese herbal medicine (CHM) has been widely used in treating neurodegenerative diseases by reducing oxidative stress and neuroinflammation. We examined the neuroprotective effect of formulated CHM Shaoyao Gancao Tang (SG-Tang, made of Paeonia lactiflora and Glycyrrhiza uralensis at 1:1 ratio) in AD cell and mouse models. In Aß-GFP SH-SY5Y cells, SG-Tang reduced Aß aggregation and reactive oxygen species (ROS) production, as well as improved neurite outgrowth. When the Aß-GFP-expressing cells were stimulated with conditioned medium from interferon (IFN)-γ-activated HMC3 microglia, SG-Tang suppressed expressions of inducible nitric oxide synthase (iNOS), NLR family pyrin domain containing 1 (NLRP1) and 3 (NLRP3), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and IL-6, attenuated caspase-1 activity and ROS production, and promoted neurite outgrowth. In streptozocin-induced hyperglycemic APP/PS1/Tau triple transgenic (3×Tg-AD) mice, SG-Tang also reduced expressions of NLRP1, NLRP3, Aß and Tau in hippocampus and cortex, as well as improved working and spatial memories in Y maze and Morris water maze. Collectively, our results demonstrate the potential of SG-Tang in treating AD by moderating neuroinflammation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Cognição , Medicamentos de Ervas Chinesas/uso terapêutico , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Neuroproteção , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/metabolismo , Animais , Linhagem Celular , Cognição/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/farmacologia , Proteínas de Fluorescência Verde/metabolismo , Humanos , Interferon gama/metabolismo , Memória/efeitos dos fármacos , Transtornos da Memória/complicações , Transtornos da Memória/fisiopatologia , Camundongos Transgênicos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Modelos Biológicos , Crescimento Neuronal/efeitos dos fármacos , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Agregados Proteicos/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Aprendizagem Espacial/efeitos dos fármacos , Proteínas tau/metabolismo
16.
Nat Commun ; 12(1): 3817, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-34155194

RESUMO

α-Synuclein is critical in the pathogenesis of Parkinson's disease and related disorders, yet it remains unclear how its aggregation causes degeneration of human dopaminergic neurons. In this study, we induced α-synuclein aggregation in human iPSC-derived dopaminergic neurons using fibrils generated de novo or amplified in the presence of brain homogenates from Parkinson's disease or multiple system atrophy. Increased α-synuclein monomer levels promote seeded aggregation in a dose and time-dependent manner, which is associated with a further increase in α-synuclein gene expression. Progressive neuronal death is observed with brain-amplified fibrils and reversed by reduction of intraneuronal α-synuclein abundance. We identified 56 proteins differentially interacting with aggregates triggered by brain-amplified fibrils, including evasion of Parkinson's disease-associated deglycase DJ-1. Knockout of DJ-1 in iPSC-derived dopaminergic neurons enhance fibril-induced aggregation and neuronal death. Taken together, our results show that the toxicity of α-synuclein strains depends on aggregate burden, which is determined by monomer levels and conformation which dictates differential interactomes. Our study demonstrates how Parkinson's disease-associated genes influence the phenotypic manifestation of strains in human neurons.


Assuntos
Neurônios Dopaminérgicos/patologia , Atrofia de Múltiplos Sistemas/patologia , Doença de Parkinson/patologia , alfa-Sinucleína/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Morte Celular , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas , Atrofia de Múltiplos Sistemas/metabolismo , Doença de Parkinson/metabolismo , Fenótipo , Agregados Proteicos , Agregação Patológica de Proteínas , Conformação Proteica , Proteína Desglicase DJ-1/metabolismo , Mapeamento de Interação de Proteínas , alfa-Sinucleína/química , alfa-Sinucleína/toxicidade
17.
Int J Mol Sci ; 22(9)2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-34066830

RESUMO

Protein solubility is based on the compatibility of the specific protein surface with the polar aquatic environment. The exposure of polar residues to the protein surface promotes the protein's solubility in the polar environment. The aquatic environment also influences the folding process by favoring the centralization of hydrophobic residues with the simultaneous exposure to polar residues. The degree of compatibility of the residue distribution, with the model of the concentration of hydrophobic residues in the center of the molecule, with the simultaneous exposure of polar residues is determined by the sequence of amino acids in the chain. The fuzzy oil drop model enables the quantification of the degree of compatibility of the hydrophobicity distribution observed in the protein to a form fully consistent with the Gaussian 3D function, which expresses an idealized distribution that meets the preferences of the polar water environment. The varied degrees of compatibility of the distribution observed with the idealized one allow the prediction of preferences to interactions with molecules of different polarity, including water molecules in particular. This paper analyzes a set of proteins with different levels of hydrophobicity distribution in the context of the solubility of a given protein and the possibility of complex formation.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Agregados Proteicos , Proteínas Anticongelantes Tipo III/química , Proteínas de Fímbrias/química , Hemoglobinas/química , Humanos , Proteínas de Membrana/química , Modelos Moleculares , Domínios Proteicos , Solubilidade
18.
Int J Mol Sci ; 22(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34064208

RESUMO

In Parkinson's disease, aggregates of α-synuclein within Lewy bodies and Lewy neurites represent neuropathological hallmarks. However, the cellular and molecular mechanisms triggering oligomeric and fibrillary α-synuclein aggregation are not fully understood. Recent evidence indicates that oxidative stress induced by metal ions and post-translational modifications such as phosphorylation, ubiquitination, nitration, glycation, and SUMOylation affect α-synuclein conformation along with its aggregation propensity and neurotoxic profiles. In addition, proteolytic cleavage of α-synuclein by specific proteases results in the formation of a broad spectrum of fragments with consecutively altered and not fully understood physiological and/or pathological properties. In the present review, we summarize the current knowledge on proteolytical α-synuclein cleavage by neurosin, calpain-1, cathepsin D, and matrix metalloproteinase-3 in health and disease. We also shed light on the contribution of the same enzymes to proteolytical processing of pathogenic proteins in Alzheimer's disease and report potential cross-disease mechanisms of pathogenic protein aggregation.


Assuntos
alfa-Sinucleína/metabolismo , Doença de Alzheimer/metabolismo , Animais , Humanos , Doença de Parkinson/metabolismo , Peptídeo Hidrolases/metabolismo , Agregados Proteicos/fisiologia , Proteólise
19.
Molecules ; 26(10)2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064874

RESUMO

ERp57, a member of the protein disulfide isomerase family, is a ubiquitous disulfide catalyst that functions in the oxidative folding of various clients in the mammalian endoplasmic reticulum (ER). In concert with ER lectin-like chaperones calnexin and calreticulin (CNX/CRT), ERp57 functions in virtually all folding stages from co-translation to post-translation, and thus plays a critical role in maintaining protein homeostasis, with direct implication for pathology. Here, we present mechanisms by which Ca2+ regulates the formation of the ERp57-calnexin complex. Biochemical and isothermal titration calorimetry analyses revealed that ERp57 strongly interacts with CNX via a non-covalent bond in the absence of Ca2+. The ERp57-CNX complex not only promoted the oxidative folding of human leukocyte antigen heavy chains, but also inhibited client aggregation. These results suggest that this complex performs both enzymatic and chaperoning functions under abnormal physiological conditions, such as Ca2+ depletion, to effectively guide proper oxidative protein folding. The findings shed light on the molecular mechanisms underpinning crosstalk between the chaperone network and Ca2+.


Assuntos
Cálcio/metabolismo , Calnexina/metabolismo , Isomerases de Dissulfetos de Proteínas/metabolismo , Dissulfetos/metabolismo , Humanos , Modelos Biológicos , Oxirredução , Agregados Proteicos , Ligação Proteica , Dobramento de Proteína , Termodinâmica
20.
Molecules ; 26(10)2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34068293

RESUMO

Alzheimer's disease is the most common type of neurodegenerative disease in the world. Genetic evidence strongly suggests that aberrant generation, aggregation, and/or clearance of neurotoxic amyloid-ß peptides (Aß) triggers the disease. Aß accumulates at the points of contact of neurons in ordered cords and fibrils, forming the so-called senile plaques. Aß isoforms of different lengths are found in healthy human brains regardless of age and appear to play a role in signaling pathways in the brain and to have neuroprotective properties at low concentrations. In recent years, different substances have been developed targeting Aß production, aggregation, interaction with other molecules, and clearance, including peptide-based drugs. Aß is a product of sequential cleavage of the membrane glycoprotein APP (amyloid precursor protein) by ß- and γ-secretases. A number of familial mutations causing an early onset of the disease have been identified in the APP, especially in its transmembrane domain. The mutations are reported to influence the production, oligomerization, and conformational behavior of Aß peptides. This review highlights the results of structural studies of the main proteins involved in Alzheimer's disease pathogenesis and the molecular mechanisms by which perspective therapeutic substances can affect Aß production and nucleation.


Assuntos
Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Conformação Proteica , Animais , Humanos , Agregados Proteicos , Mapas de Interação de Proteínas , Proteólise
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