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1.
Commun Biol ; 5(1): 417, 2022 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-35513705

RESUMO

Amyloid-ß (Aß) and semen-derived enhancer of viral infection (SEVI) are considered as the two causative proteins for central pathogenic cause of Alzheimer's disease (AD) and HIV/AIDS, respectively. Separately, Aß-AD and SEVI-HIV/AIDS systems have been studied extensively both in fundamental research and in clinical trials. Despite significant differences between Aß-AD and SEVI-HIV/AIDS systems, they share some commonalities on amyloid and antimicrobial characteristics between Aß and SEVI, there are apparent overlaps in dysfunctional neurological symptoms between AD and HIV/AIDS. Few studies have reported a potential pathological link between Aß-AD and SEVI-HIV/AIDS at a protein level. Here, we demonstrate the cross-seeding interactions between Aß and SEVI proteins using in vitro and in vivo approaches. Cross-seeding of SEVI with Aß enabled to completely prevent Aß aggregation at sub-stoichiometric concentrations, disaggregate preformed Aß fibrils, reduce Aß-induced cell toxicity, and attenuate Aß-accumulated paralysis in transgenic AD C. elegans. This work describes a potential crosstalk between AD and HIV/AIDS via the cross-seeding between Aß and SEVI, identifies SEVI as Aß inhibitor for possible treatment or prevention of AD, and explains the role of SEVI in the gender difference in AD.


Assuntos
Síndrome de Imunodeficiência Adquirida , Doença de Alzheimer , Infecções por HIV , Viroses , Doença de Alzheimer/genética , Amiloide/metabolismo , Peptídeos beta-Amiloides , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Infecções por HIV/metabolismo , Sementes , Fatores Sexuais
2.
Nat Commun ; 13(1): 2363, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35501361

RESUMO

Chaperones, as modulators of protein conformational states, are key cellular actors to prevent the accumulation of fibrillar aggregates. Here, we integrated kinetic investigations with structural studies to elucidate how the ubiquitous co-chaperonin prefoldin inhibits diabetes associated islet amyloid polypeptide (IAPP) fibril formation. We demonstrated that both human and archaeal prefoldin interfere similarly with the IAPP fibril elongation and secondary nucleation pathways. Using archaeal prefoldin model, we combined nuclear magnetic resonance spectroscopy with electron microscopy to establish that the inhibition of fibril formation is mediated by the binding of prefoldin's coiled-coil helices to the flexible IAPP N-terminal segment accessible on the fibril surface and fibril ends. Atomic force microscopy demonstrates that binding of prefoldin to IAPP leads to the formation of lower amounts of aggregates, composed of shorter fibrils, clustered together. Linking structural models with observed fibrillation inhibition processes opens perspectives for understanding the interference between natural chaperones and formation of disease-associated amyloids.


Assuntos
Polipeptídeo Amiloide das Ilhotas Pancreáticas , Chaperonas Moleculares , Amiloide/metabolismo , Chaperoninas , Humanos , Chaperonas Moleculares/metabolismo
3.
Cell Rep ; 39(5): 110753, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35508136

RESUMO

Amyloids are fibrous protein aggregates associated with age-related diseases. While these aggregates are typically described as irreversible and pathogenic, some cells use reversible amyloid-like structures that serve important functions. The RNA-binding protein Rim4 forms amyloid-like assemblies that are essential for translational control during Saccharomyces cerevisiae meiosis. Rim4 amyloid-like assemblies are disassembled in a phosphorylation-dependent manner at meiosis II onset. By investigating Rim4 clearance, we elucidate co-factors that mediate clearance of amyloid-like assemblies in a physiological setting. We demonstrate that yeast 14-3-3 proteins bind to Rim4 assemblies and facilitate their subsequent phosphorylation and timely clearance. Furthermore, distinct 14-3-3 proteins play non-redundant roles in facilitating phosphorylation and clearance of amyloid-like Rim4. Additionally, we find that 14-3-3 proteins contribute to global protein aggregate homeostasis. Based on the role of 14-3-3 proteins in aggregate homeostasis and their interactions with disease-associated assemblies, we propose that these proteins may protect against pathological protein aggregates.


Assuntos
Proteínas de Saccharomyces cerevisiae , Proteínas 14-3-3/metabolismo , Amiloide/metabolismo , Proteínas Amiloidogênicas/metabolismo , Agregados Proteicos , Proteínas de Ligação a RNA/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
4.
J Chem Phys ; 156(16): 164904, 2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35490011

RESUMO

Protein self-assembly into amyloid fibrils underlies several neurodegenerative conditions, including Alzheimer's and Parkinson's diseases. It has become apparent that the small oligomers formed during this process constitute neurotoxic molecular species associated with amyloid aggregation. Targeting the formation of oligomers represents, therefore, a possible therapeutic avenue to combat these diseases. However, it remains challenging to establish which microscopic steps should be targeted to suppress most effectively the generation of oligomeric aggregates. Recently, we have developed a kinetic model of oligomer dynamics during amyloid aggregation. Here, we use this approach to derive explicit scaling relationships that reveal how key features of the time evolution of oligomers, including oligomer peak concentration and lifetime, are controlled by the different rate parameters. We discuss the therapeutic implications of our framework by predicting changes in oligomer concentrations when the rates of the individual microscopic events are varied. Our results identify the kinetic parameters that control most effectively the generation of oligomers, thus opening a new path for the systematic rational design of therapeutic strategies against amyloid-related diseases.


Assuntos
Amiloide , Doenças Neurodegenerativas , Amiloide/metabolismo , Proteínas Amiloidogênicas , Humanos , Cinética
5.
Methods Mol Biol ; 2491: 471-490, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35482203

RESUMO

Conformational antibodies specific for amyloid-forming peptides and proteins are important for a range of biomedical applications, including detecting, inhibiting, and potentially treating protein aggregation disorders ranging from Alzheimer's to Parkinson's diseases. Generation of anti-amyloid antibodies is greatly complicated by the complex, heterogeneous and insoluble nature of amyloid antigens. Here we describe systematic methods for isolating and affinity maturing anti-amyloid antibodies using yeast surface display. Magnetic-activated cell sorting is used to sort single-chain antibody libraries positively for binding to amyloid antigens and negatively against the corresponding disaggregated antigens to remove antibodies that bind in a conformation-independent manner. Isolated lead antibody clones with conformational specificity are affinity matured via targeted CDR mutagenesis and magnetic-activated cell sorting.


Assuntos
Amiloide , Saccharomyces cerevisiae , Amiloide/metabolismo , Proteínas Amiloidogênicas/genética , Proteínas Amiloidogênicas/metabolismo , Anticorpos/química , Agregados Proteicos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
6.
Nat Commun ; 13(1): 2273, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35477706

RESUMO

Parkinson's disease (PD) is a progressive neurodegenerative disorder for which there is no successful prevention or intervention. The pathological hallmark for PD involves the self-assembly of functional Alpha-Synuclein (αS) into non-functional amyloid structures. One of the potential therapeutic interventions against PD is the effective inhibition of αS aggregation. However, the bottleneck towards achieving this goal is the identification of αS domains/sequences that are essential for aggregation. Using a protein mimetic approach, we have identified αS sequences-based targets that are essential for aggregation and will have significant therapeutic implications. An extensive array of in vitro, ex vivo, and in vivo assays is utilized to validate αS sequences and their structural characteristics that are essential for aggregation and propagation of PD phenotypes. The study aids in developing significant mechanistic and therapeutic insights into various facets of αS aggregation, which will pave the way for effective treatments for PD.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Amiloide/metabolismo , Humanos , Doença de Parkinson/metabolismo , alfa-Sinucleína/metabolismo
7.
Biochim Biophys Acta Gen Subj ; 1866(7): 130151, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35421539

RESUMO

α-Synuclein (α-Syn) aggregation/fibrillation is a leading cause of neuronal death and is one of the major pathogenic factors involved in the progression of Parkinson's' disease (PD). Against this backdrop, discovering new molecules as inhibitors or modulators of α-Syn aggregation/fibrillation is a subject of enormous research. In this study, we have shown modulation, disaggregation, and neuroprotective potential of aloin and emodin against α-Syn aggregation/fibrillation. Thioflavin T (ThT) fluorescence assay showed an increase in lag phase from (51.14 ± 2) h to (68.58 ± 2) h and (74.14 ± 3) h in the presence of aloin and emodin respectively. ANS binding assay represents a modulatory effect of these molecules on hydrophobicity which is crucial for aggregates/fibril formation. NMR spectroscopy and tyrosine quenching studies reveal the binding of aloin/emodin with monomeric α-Syn. TEM and DLS micrographs illustrate the attenuating effect of aloin/emodin against the development of large aggregates/fibrils. Our seeding experiments suggest aloin/emodin generate seeding incompetent oligomers that direct the off-pathway aggregation/fibrillation. Also, aloin/emodin capably reduces the fibrils-induced cytotoxicity and disassembles the preexisting amyloid fibrils. These findings provide deep insight into the modulatory mechanism of α-Syn aggregation/fibrillation in the presence of aloin and emodin, thereby suggesting their potential roles as promising therapeutic molecules against aggregation/fibrillation related disorders.


Assuntos
Emodina , Doença de Parkinson , Amiloide/metabolismo , Emodina/análogos & derivados , Emodina/farmacologia , Humanos , Doença de Parkinson/tratamento farmacológico , alfa-Sinucleína/química
8.
Int J Biol Macromol ; 208: 1072-1081, 2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35381286

RESUMO

As a major microtubule-associated protein, tau is involved in the assembly of microtubules in the central nervous system. However, under pathological conditions tau assembles into amyloid filaments. Liquid droplets formed by liquid-liquid phase separation (LLPS) are a recently identified assembly state of tau and may have a major effect on the physiological function of tau and the formation of tau aggregates. 14-3-3 proteins are ubiquitously expressed in various tissues and regulate a wide variety of biological processes. In this work, we demonstrate that 14-3-3ζ is recruited into tau droplets and regulates tau LLPS by in vitro assays. While the mobility of tau molecules inside the droplets is not affected in the presence of 14-3-3ζ, the amount and size of droplets can vary significantly. Mechanistic studies reveal that 14-3-3ζ regulates tau LLPS by electrostatic interactions and hydrophobic interactions with the proline-rich domain and the microtubule-binding domain of tau. Surprisingly, the disordered C-terminal tail rather than the amphipathic binding groove of 14-3-3ζ plays a key role. Our findings not only provide a novel dimension to understand the interactions between 14-3-3 proteins and tau, but also suggest that 14-3-3 proteins may play an important role in regulating the LLPS of their binding partners.


Assuntos
Proteínas 14-3-3 , Proteínas tau , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Amiloide/metabolismo , Humanos , Simulação de Dinâmica Molecular , Agregação Patológica de Proteínas/metabolismo , Proteínas tau/química
9.
JCI Insight ; 7(7)2022 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-35393947

RESUMO

Amyloidosis involves stepwise growth of fibrils assembled from soluble precursors. Transthyretin (TTR) naturally folds into a stable tetramer, whereas conditions and mutations that foster aberrant monomer formations facilitate TTR oligomeric aggregation and subsequent fibril extension. We investigated the early assembly of oligomers by WT TTR compared with its V30M and V122I variants. We monitored time-dependent redistribution among monomer, dimer, tetramer, and oligomer contents in the presence and absence of multimeric TTR seeds. The seeds were artificially constructed recombinant multimers that contained 20-40 TTR subunits via engineered biotin-streptavidin (SA) interactions. As expected, these multimer seeds rapidly nucleated TTR monomers into larger complexes, while having less effect on dimers and tetramers. In vivo, SA-induced multimers formed TTR-like deposits in the heart and the kidney following i.v. injection in mice. While all 3 variants prominently deposited glomerulus in the kidney, only V30M resulted in extensive deposition in the heart. The cardiac TTR deposits varied in size and shape and were localized in the intermyofibrillar space along the capillaries. These results are consistent with the notion of monomeric TTR engaging in high-avidity interactions with tissue amyloids. Our multimeric induction approach provides a model for studying the initiation of TTR deposition in the heart.


Assuntos
Amiloide , Pré-Albumina , Amiloide/química , Amiloide/genética , Amiloide/metabolismo , Animais , Camundongos , Pré-Albumina/genética
10.
Minerva Cardiol Angiol ; 70(2): 248-257, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35412035

RESUMO

Transthyretin (TTR) is a tetrameric protein synthesized mostly by the liver. As a result of gene mutations or as an ageing-related phenomenon, TTR molecules may misfold and deposit in the heart and in other organs as amyloid fibrils. Amyloid transthyretin cardiac amyloidosis (ATTR-CA) manifests typically as left ventricular pseudohypertrophy and/or heart failure with preserved ejection fraction and is an underdiagnosed disorder affecting quality of life and prognosis. This justifies the current search for novel tools for early diagnosis and accurate risk prediction, as well as for safe and effective therapies. In this review we will provide an overview of the main unsolved issues and the most promising research lines on ATTR-CA, ranging from the mechanisms of amyloid formation to therapies.


Assuntos
Neuropatias Amiloides Familiares , Cardiologia , Amiloide/genética , Amiloide/metabolismo , Neuropatias Amiloides Familiares/complicações , Neuropatias Amiloides Familiares/diagnóstico , Neuropatias Amiloides Familiares/genética , Proteínas Amiloidogênicas , Humanos , Pré-Albumina/genética , Pré-Albumina/metabolismo , Qualidade de Vida
11.
Biomolecules ; 12(3)2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35327638

RESUMO

Amyloid formation is a pathological process associated with a wide range of degenerative disorders, including Alzheimer's disease, Parkinson's disease, and diabetes mellitus type 2. During disease progression, abnormal accumulation and deposition of proteinaceous material are accompanied by tissue degradation, inflammation, and dysfunction. Agents that can interfere with the process of amyloid formation or target already formed amyloid assemblies are consequently of therapeutic interest. In this context, a few endogenous proteins have been associated with an anti-amyloidogenic activity. Here, we review the properties of transthyretin, apolipoprotein E, clusterin, and BRICHOS protein domain which all effectively interfere with amyloid in vitro, as well as displaying a clinical impact in humans or animal models. Their involvement in the amyloid formation process is discussed, which may aid and inspire new strategies for therapeutic interventions.


Assuntos
Doença de Alzheimer , Amiloidose , Doença de Parkinson , Amiloide/metabolismo , Peptídeos beta-Amiloides , Proteínas Amiloidogênicas/metabolismo , Animais , Humanos , Doença de Parkinson/metabolismo , alfa-Sinucleína/metabolismo
12.
Cell Tissue Res ; 388(2): 211-223, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35258715

RESUMO

Estimating the amyloid level in yeast Saccharomyces, we found out that the red pigment (product of polymerization of aminoimidazole ribotide) accumulating in ade1 and ade2 mutants leads to drop of the amyloid content. We demonstrated in vitro that fibrils of several proteins grown in the presence of the red pigment stop formation at the protofibril stage and form stable aggregates due to coalescence. Also, the red pigment inhibits reactive oxygen species accumulation in cells. This observation suggests that red pigment is involved in oxidative stress response. We developed an approach to identify the proteins whose aggregation state depends on prion (amyloid) or red pigment presence. These sets of proteins overlap and in both cases involve many different chaperones. Red pigment binds amyloids and is supposed to prevent chaperone-mediated prion propagation. An original yeast-Drosophila model was offered to estimate the red pigment effect on human proteins involved in neurodegeneration. As yeast cells are a natural feed of Drosophila, we could compare the data on transgenic flies fed on red and white yeast cells. Red pigment inhibits aggregation of human Amyloid beta and α-synuclein expressed in yeast cells. In the brain of transgenic flies, the red pigment diminishes amyloid beta level and the area of neurodegeneration. An improvement in memory and viability accompanied these changes. In transgenic flies expressing human α-synuclein, the pigment leads to a decreased death rate of dopaminergic neurons and improves mobility. The obtained results demonstrate yeast red pigment potential for the treatment of neurodegenerative diseases.


Assuntos
Amiloidose , Príons , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Animais Geneticamente Modificados , Drosophila , Príons/metabolismo , Agregados Proteicos , Saccharomyces cerevisiae/metabolismo , alfa-Sinucleína/metabolismo
13.
Methods Mol Biol ; 2405: 95-113, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35298810

RESUMO

Amyloid fibril formation is an intrinsic property of short peptides, non-disease proteins, and proteins associated with neurodegenerative diseases. Aggregates of the Aß and tau proteins, the α-synuclein protein, and the prion protein are observed in the brain of Alzheimer's, Parkinson's, and prion disease patients, respectively. Due to the transient short-range and long-range interactions of all species and their high aggregation propensities, the conformational ensemble of these devastating proteins, the exception being for the monomeric prion protein, remains elusive by standard structural biology methods in bulk solution and in lipid membranes. To overcome these limitations, an increasing number of simulations using different sampling methods and protein models have been performed. In this chapter, we first review our main contributions to the field of amyloid protein simulations aimed at understanding the early aggregation steps of short linear amyloid peptides, the conformational ensemble of the Aß40/42 dimers in bulk solution, and the stability of Aß aggregates in lipid membrane models. Then we focus on our studies on the interactions of amyloid peptides/inhibitors to prevent aggregation, and long amyloid sequences, including new results on a monomeric tau construct.


Assuntos
Doença de Alzheimer , Amiloide , Amiloidose , Doença de Parkinson , Doenças Priônicas , Doença de Alzheimer/metabolismo , Amiloide/química , Amiloide/metabolismo , Amiloidose/metabolismo , Humanos , Doença de Parkinson/metabolismo , Doenças Priônicas/metabolismo , Proteínas tau
14.
Biochem Biophys Res Commun ; 603: 13-20, 2022 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-35276458

RESUMO

α-Synuclein (α-Syn) is an aggregation-prone protein whose accumulation in Lewy bodies leads to neurodegenerative diseases like Parkinson's disease (PD). Calcium plays a critical role in neurons, and calcium dysregulation is one of the risk factors of PD. It is known that Ca2+ interacts with α-Syn and affects its assembly. However, how Ca2+ regulates α-Syn aggregation remains unclear. Here, we reported that Ca2+ accelerates α-Syn amyloid aggregation through the modulation of protein phase separation. We observed that Ca2+ promotes the formation of α-Syn liquid droplets but does not change the protein fluidity inside the droplets. Further studies showed Ca2+-involved α-Syn droplets are still able to fuse. A metal chelator eliminated Ca2+-induced enlargement of α-Syn droplets, suggesting the influence of Ca2+ on α-Syn assembly could be reversed at the stage of liquid-liquid phase separation (LLPS). Interestingly, our data showed Ca2+ still promoted α-Syn phase separation in the presence of the lipid membranes. In addition, Ca2+/α-syn droplets could efficiently recruit lipid vesicles to the surface of these condensates. Our findings demonstrate that Ca2+ facilitates α-Syn phase separation to accelerate amyloid aggregation and pave the path for understanding the implications of Ca2+ in α-Syn accumulation and PD.


Assuntos
Amiloidose , Cálcio , Doença de Parkinson , Amiloide/metabolismo , Proteínas Amiloidogênicas , Humanos , Corpos de Lewy/metabolismo , Lipídeos , Doença de Parkinson/metabolismo , alfa-Sinucleína/metabolismo
15.
Cell Mol Life Sci ; 79(3): 174, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35244787

RESUMO

Protein misfolding is a general hallmark of protein deposition diseases, such as Alzheimer's disease or Parkinson's disease, in which different types of aggregated species (oligomers, protofibrils and fibrils) are generated by the cells. Despite widespread interest, the relationship between oligomers and fibrils in the aggregation process and spreading remains elusive. A large variety of experimental evidences supported the idea that soluble oligomeric species of different proteins might be more toxic than the larger fibrillar forms. Furthermore, the lack of correlation between the presence of the typical pathological inclusions and disease sustained this debate. However, recent data show that the ß-sheet core of the α-Synuclein (αSyn) fibrils is unable to establish persistent interactions with the lipid bilayers, but they can release oligomeric species responsible for an immediate dysfunction of the recipient neurons. Reversibly, such oligomeric species could also contribute to pathogenesis via neuron-to-neuron spreading by their direct cell-to-cell transfer or by generating new fibrils, following their neuronal uptake. In this Review, we discuss the various mechanisms of cellular dysfunction caused by αSyn, including oligomer toxicity, fibril toxicity and fibril spreading.


Assuntos
Amiloide/metabolismo , Sinucleinopatias/patologia , alfa-Sinucleína/metabolismo , Amiloide/toxicidade , Humanos , Corpos de Lewy/metabolismo , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Agregados Proteicos , Dobramento de Proteína , Sinucleinopatias/metabolismo , alfa-Sinucleína/química , alfa-Sinucleína/genética
16.
Biomolecules ; 12(3)2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-35327591

RESUMO

Passive immunotherapy is a very promising approach for the treatment of Alzheimer's disease (AD). Among the different antibodies under development, those targeting post-translationally modified Aß peptides might combine efficient reduction in beta-amyloid accompanied by lower sequestration in peripheral compartments and thus anticipated and reduced treatment-related side effects. In that regard, we recently demonstrated that the antibody-mediated targeting of isoD7-modified Aß peptides leads to the attenuation of AD-like amyloid pathology in 5xFAD mice. In order to assess novel strategies to enhance the efficacy of passive vaccination approaches, we investigated the role of CD33 for Aß phagocytosis in transgenic mice treated with an isoD7-Aß antibody. We crossbred 5xFAD transgenic mice with CD33 knock out (CD33KO) mice and compared the amyloid pathology in the different genotypes of the crossbreds. The knockout of CD33 in 5xFAD mice leads to a significant reduction in Aß plaques and concomitant rescue of behavioral deficits. Passive immunotherapy of 5xFAD/CD33KO showed a significant increase in plaque-surrounding microglia compared to 5xFAD treated with the antibody. Additionally, we observed a stronger lowering of Aß plaque load after passive immunotherapy in 5xFAD/CD33KO mice. The data suggest an additive effect of passive immunotherapy and CD33KO in terms of lowering Aß pathology. Hence, a combination of CD33 antagonists and monoclonal antibodies might represent a strategy to enhance efficacy of passive immunotherapy in AD.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/terapia , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Imunização Passiva , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Placa Amiloide/patologia
17.
Nat Commun ; 13(1): 1351, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35292653

RESUMO

Heterotypic amyloid interactions between related protein sequences have been observed in functional and disease amyloids. While sequence homology seems to favour heterotypic amyloid interactions, we have no systematic understanding of the structural rules determining such interactions nor whether they inhibit or facilitate amyloid assembly. Using structure-based thermodynamic calculations and extensive experimental validation, we performed a comprehensive exploration of the defining role of sequence promiscuity in amyloid interactions. Using tau as a model system we demonstrate that proteins with local sequence homology to tau amyloid nucleating regions can modify fibril nucleation, morphology, assembly and spreading of aggregates in cultured cells. Depending on the type of mutation such interactions inhibit or promote aggregation in a manner that can be predicted from structure. We find that these heterotypic amyloid interactions can result in the subcellular mis-localisation of these proteins. Moreover, equilibrium studies indicate that the critical concentration of aggregation is altered by heterotypic interactions. Our findings suggest a structural mechanism by which the proteomic background can modulate the aggregation propensity of amyloidogenic proteins and we discuss how such sequence-specific proteostatic perturbations could contribute to the selective cellular susceptibility of amyloid disease progression.


Assuntos
Amiloidose , Proteômica , Sequência de Aminoácidos , Amiloide/metabolismo , Proteínas Amiloidogênicas/metabolismo , Humanos
18.
Bioorg Med Chem Lett ; 64: 128677, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35301136

RESUMO

Preventing the aggregation of certain amyloid proteins has the potential to slow down the progression of diseases like Alzheimer's, Parkinson's, and type 2 diabetes mellitus. During a high-throughput screen of 300 Australian marine invertebrate extracts, the extract of the marine sponge Thorectandra sp. 4408 displayed binding activity to the Parkinson's disease-associated protein, α-synuclein. Isolation of the active component led to its identification as the known plant growth promoter asterubine (1). This molecule shares distinct structural similarities with potent amyloid beta aggregation inhibitors tramiprosate (homotaurine) and ALZ-801. Herein we report the isolation, NMR data acquired in DMSO and α-synuclein binding activity of asterubine (1).


Assuntos
Diabetes Mellitus Tipo 2 , Doença de Parkinson , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Austrália , Humanos , Doença de Parkinson/metabolismo , alfa-Sinucleína
19.
Proc Natl Acad Sci U S A ; 119(15): e2109617119, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35353605

RESUMO

SignificanceConverging evidence points to the build-up of phosphorylated α-synuclein (α-syn) at residue serine 129 (pS129) in Lewy body disease, suggesting its central role in the regulation of α-syn aggregation and neuronal degeneration. However, a comprehensive understanding of the role of α-syn phosphorylation at pS129 in α-synuclenopathies pathogenesis is still lacking. Herein, we study the phosphorylation incidence and its effect on α-syn aggregation propensity and cellular toxicity. Collectively, our data suggest that pS129 occurred subsequent to initial α-syn aggregation, lessened aggregation propensity, and attenuated cytotoxicity through diverse assays. Our findings highlight major implications for a better understanding of the role of a molecular modification on protein aggregation.


Assuntos
Amiloide , Doença por Corpos de Lewy , Doença de Parkinson , Agregação Patológica de Proteínas , alfa-Sinucleína , Amiloide/metabolismo , Humanos , Doença por Corpos de Lewy/genética , Doença por Corpos de Lewy/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Fosforilação , Agregados Proteicos , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Serina/metabolismo , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo
20.
Proc Natl Acad Sci U S A ; 119(14): e2113520119, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-35349341

RESUMO

SignificanceClassic serine proteases are synthesized as inactive precursors that are proteolytically processed, resulting in irreversible activation. We report an alternative and reversible mechanism of activation that is executed by an inactive protease. This mechanism involves a protein complex between the serine protease HTRA1 and the cysteine protease calpain 2. Surprisingly, activation is restricted as it improves the proteolysis of soluble tau protein but not the dissociation and degradation of its amyloid fibrils, a task that free HTRA1 is efficiently performing. These data exemplify a challenge for protein quality control proteases in the clearing of pathogenic fibrils and suggest a potential for unexpected side effects of chemical modulators targeting PDZ or other domains located at a distance to the active site.


Assuntos
Calpaína , Serina Endopeptidases , Amiloide/metabolismo , Calpaína/metabolismo , Serina Peptidase 1 de Requerimento de Alta Temperatura A/química , Proteólise , Serina Endopeptidases/metabolismo , Serina Proteases/metabolismo
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