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1.
Food Chem ; 462: 140996, 2025 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-39213962

RESUMO

The mechanisms of trypsin hydrolysis time on the structure of soy protein hydrolysate fibril aggregates (SPHFAs) and the stability of SPHFAs-high internal phase Pickering emulsions (HIPPEs) were investigated. SPHFAs were prepared using soy protein hydrolysate (SPH) with different trypsin hydrolysis time (0 min-120 min) to stabilize SPHFAs-HIPPEs. The results showed that moderate trypsin hydrolysis (30 min, hydrolysis degree of 2.31 %) induced SPH unfolding and increased the surface hydrophobicity of SPH, thereby promoting the formation of flexible SPHFAs with maximal thioflavin T intensity and ζ-potential. Moreover, moderate trypsin hydrolysis improved the viscoelasticity of SPHFAs-HIPPEs, and SPHFAs-HIPPEs remained stable after storage at 25 °C for 80 d and heating at 100 °C for 1 h. Excessive trypsin hydrolysis (> 30 min) decreased the stability of SPHFAs-HIPPEs. In conclusion, moderate trypsin hydrolysis promoted the formation of flexible SPHFAs with high surface charge by inducing SPH unfolding, thereby promoting the stability of SPHFAs-HIPPEs.


Assuntos
Emulsões , Interações Hidrofóbicas e Hidrofílicas , Hidrolisados de Proteína , Proteínas de Soja , Tripsina , Tripsina/química , Hidrólise , Emulsões/química , Proteínas de Soja/química , Hidrolisados de Proteína/química , Agregados Proteicos
2.
Food Chem ; 462: 141004, 2025 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-39216378

RESUMO

This study assessed the effect of konjac glucomannan (KGM) on the aggregation of soy protein isolate (SPI) and its gel-related structure and properties. Raman results showed that KGM promoted the rearrangement of SPI to form more ß-sheets, contributing to the formation of an ordered structure. Atomic force microscopy, confocal laser scanning microscopy, and small-angle X-ray scattering results indicated that KGM reduced the size of SPI particles, narrowed their size distribution, and loosened the large aggregates formed by the stacking of SPI particles, improving the uniformity of gel system. As the hydrogen bonding between the KGM and SPI molecules enhanced, a well-developed network structure was obtained, further reducing the immobilized water's content (T22) and increasing the water-holding capacity (WHC) of SPI gel. Furthermore, this gel structure showed improved gel hardness and resistance to both small and large deformations. These findings facilitate the design and production of SPI-based gels with desired performance.


Assuntos
Géis , Mananas , Proteínas de Soja , Proteínas de Soja/química , Mananas/química , Géis/química , Tamanho da Partícula , Agregados Proteicos
3.
Ultrason Sonochem ; 110: 107059, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39250863

RESUMO

The aim of the present study was to evaluate the effects of ultrasound-assisted intermittent tumbling (UT) at 300 W, 20 kHz and 40 min on the conformation, intermolecular interactions and aggregation of myofibrillar proteins (MPs) and its induced gelation properties at various tumbling times (4 and 6 h). Raman results showed that all tumbling treatments led the helical structure of MPs to unfold. In comparison to the single intermittent tumbling treatment (ST), UT treatment exerted more pronounced effects on strengthening the intermolecular hydrogen bonds and facilitating the formation of an ordered ß-sheet structure. When the tumbling time was the same, UT treatment caused higher surface hydrophobicity, fluorescence intensity and disulfide bond content in the MPs, inducing the occurrence of hydrophobic interaction and disulfide cross-linking between MPs molecules, thus forming the MPs aggregates. Additionally, results from the solubility, particle size, atomic force microscopy and SDS-PAGE further indicated that, relative to the ST treatment, UT treatment was more potent in promoting the polymerization of myosin heavy chain. The MPs aggregates in the UT group were more uniform than those in the ST group. During the gelation process, the pre-formed MPs aggregates in the UT treatment increased the thermal stability of myosin, rendering it more resistant to heat-induced unfolding of the myosin rod region. Furthermore, they improved the protein tail-tail interaction, resulting in the formation of a well-structured gel network with higher gel strength and cooking yield compared to the ST treatment.


Assuntos
Géis , Miofibrilas , Reologia , Géis/química , Miofibrilas/química , Ondas Ultrassônicas , Proteínas Musculares/química , Conformação Proteica , Interações Hidrofóbicas e Hidrofílicas , Animais , Agregados Proteicos
4.
Colloids Surf B Biointerfaces ; 244: 114185, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39226848

RESUMO

Supramolecular medicine refers to the formulation of therapeutic and diagnostic agents through supramolecular techniques, amid treating, diagnosing, and preventing disease. Recently, there has been growing interest in developing metal nanoparticles (MNPs)-amyloid hybrid materials, which have the potential to revolutionize medical applications. Furthermore, the development of MNPs-amyloid hydrogel/scaffold supramolecules represents a promising new direction in amyloid nanotechnology, with potential applications in tissue engineering and biomedicine. This review first provides a brief introduction to the formation process of protein amyloid aggregates and their unique nanostructures. Subsequently, we focused on recent investigations into the use of MNPs-amyloid hybrid materials in tissue engineering and biomedicine. We anticipate that MNPs-amyloid supramolecular materials will pave the way for new functional materials in medical science, particularly in the field of tissue engineering.


Assuntos
Proteínas Amiloidogênicas , Sistemas de Liberação de Medicamentos , Nanopartículas Metálicas , Engenharia Tecidual , Engenharia Tecidual/métodos , Nanopartículas Metálicas/química , Sistemas de Liberação de Medicamentos/métodos , Agregados Proteicos , Alicerces Teciduais/química , Proteínas Amiloidogênicas/química , Dobramento de Proteína , Conformação Proteica , Humanos
5.
Sci Rep ; 14(1): 20867, 2024 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-39242711

RESUMO

Huntington's disease (HD) is a rare neurodegenerative disease caused due to aggregation of Huntingtin (HTT) protein. This study involves the cloning of 40 DnaJ chaperones from Drosophila, and overexpressing them in yeasts and fly models of HD. Accordingly, DnaJ chaperones were catalogued as enhancers or suppressors based on their growth phenotypes and aggregation properties. 2 of the chaperones that came up as targets were CG5001 and P58IPK. Protein aggregation and slow growth phenotype was rescued in yeasts, S2 cells, and Drosophila transgenic lines of HTT103Q with these overexpressed chaperones. Since DnaJ chaperones have protein sequence similarity across species, they can be used as possible tools to combat the effects of neurodegenerative diseases.


Assuntos
Proteínas de Drosophila , Proteínas de Choque Térmico HSP40 , Proteína Huntingtina , Doença de Huntington , Animais , Humanos , Animais Geneticamente Modificados , Modelos Animais de Doenças , Drosophila , Drosophila melanogaster , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP40/metabolismo , Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/genética , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Agregados Proteicos , Agregação Patológica de Proteínas/genética , Saccharomyces cerevisiae
6.
Sci Rep ; 14(1): 21464, 2024 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-39271700

RESUMO

The inner capsid protein of rotavirus, VP6, emerges as a promising candidate for next-generation vaccines against rotaviruses owing to its abundance in virion particles and high conservation. However, the formation of inclusion bodies during prokaryotic VP6 expression poses a significant hurdle to rotavirus research and applications. Here, we employed experimental and computational approaches to investigate inclusion body formation and aggregation-prone regions (APRs). Heterologous recombinant VP6 expression in Escherichia coli BL21(DE3) cells resulted in inclusion body formation, confirmed by transmission electron microscopy revealing amorphous aggregates. Thioflavin T assay demonstrated incubation temperature-dependent aggregation of VP6 inclusion bodies. Computational predictions of APRs in rotavirus A VP6 protein were performed using sequence-based tools (TANGO, AGGRESCAN, Zyggregator, Waltz, FoldAmyloid, ANuPP, Camsol intrinsic) and structure-based tools (SolubiS, CamSol structurally corrected, Aggrescan3D). A total of 24 consensus APRs were identified, with 21 of them being surface-exposed in VP6. All identified APRs display a predominance of hydrophobic amino acids, ranging from 33 to 100%. Computational identification of these APRs corroborates our experimental observation of VP6 inclusion body or aggregate formation. Characterization of VP6's aggregation propensity facilitates understanding of its behaviour during prokaryotic expression and opens avenues for protein engineering of soluble variants, advancing research on rotavirus VP6 in pathology, therapy, and diagnostics.


Assuntos
Antígenos Virais , Proteínas do Capsídeo , Escherichia coli , Corpos de Inclusão , Rotavirus , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Antígenos Virais/genética , Antígenos Virais/metabolismo , Corpos de Inclusão/metabolismo , Rotavirus/genética , Rotavirus/metabolismo , Agregados Proteicos , Simulação por Computador , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
7.
Commun Biol ; 7(1): 1143, 2024 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-39277689

RESUMO

Alzheimer's disease (AD) and more than twenty other dementias, termed tauopathies, are pathologically defined by insoluble aggregates of the microtubule-associated protein tau (MAPT). Although tau aggregation correlates with AD symptomology, the specific tau species, i.e., monomers, soluble oligomers, and insoluble aggregates that induce neurotoxicity are incompletely understood. We developed a light-responsive tau protein (optoTAU) and used viscosity-sensitive AggFluor probes to investigate the consequence(s) of tau aggregation in human neurons and identify modifiers of tau aggregation in AD and other tauopathies. We determined that optoTAU reproduces biological and structural properties of tau aggregation observed in human brains and the pathophysiological transition in tau solubility in live cells. We also provide proof-of-concept for the utilization of optoTAU as a pharmacological platform to identify modifiers of tau aggregation. These findings have broad implications for the characterization of aggregation-prone proteins and investigation of the complex relationship between protein solubility, cellular function, and disease progression.


Assuntos
Neurônios , Agregação Patológica de Proteínas , Proteínas tau , Proteínas tau/metabolismo , Proteínas tau/química , Humanos , Neurônios/metabolismo , Agregação Patológica de Proteínas/metabolismo , Agregados Proteicos , Tauopatias/metabolismo , Tauopatias/patologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Solubilidade
8.
Acta Pharm ; 74(3): 479-493, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39279529

RESUMO

The formulation of biopharmaceutical drugs is designed to eliminate chemical instabilities, increase conformational and colloidal stability of proteins, and optimize interfacial stability. Among the various excipients involved, buffer composition plays a pivotal role. However, conventional buffers like histidine and phosphate buffers may not always be the optimal choice for all monoclonal antibodies (mAbs). In this study, we investigated the effects of several alternative buffer systems on seven different mAbs, exploring various combinations of ionic strengths, concentrations of the main buffer component, mAb concentrations, and stress conditions. Protein stability was assessed by analyzing soluble aggregate formation through size exclusion chromatography. At low protein concentrations, protein instability after temperature stress was exclusively observed in the bis-TRIS/ glucuronate buffer. Conversely, freeze-thaw stress led to a significant increase in aggregate formation in tested formulations, highlighting the efficacy of several alternative buffers, particularly arginine/ citrate, in preserving protein stability. Under temperature stress, the introduction of arginine to histidine buffer systems provided additional stabilization, while the addition of lysine resulted in protein destabilization. Similarly, the incorporation of arginine into histi-dine/HCl buffer further enhanced protein stability during freeze--thaw cycles. At high protein concentrations, the histidine/citrate buffer emerged as one of the most optimal choices for addressing temperature and light-induced stress. The efficacy of histidine buffers in combating light stress might be attributed to the light-absorbing properties of histidine molecules. Our findings demonstrate that the development of biopharmaceutical formulations should not be confined to conventional buffer systems, as numerous alternative options exhibit comparable or even superior performance.


Assuntos
Anticorpos Monoclonais , Excipientes , Estabilidade Proteica , Soluções Tampão , Anticorpos Monoclonais/química , Excipientes/química , Concentração Osmolar , Composição de Medicamentos/métodos , Temperatura , Estabilidade de Medicamentos , Histidina/química , Congelamento , Química Farmacêutica/métodos , Arginina/química , Agregados Proteicos
9.
Mikrochim Acta ; 191(10): 573, 2024 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-39227417

RESUMO

Tannic acid (TA)-derived carbon dots (TACDs) were synthesized for the first time via a solvothermal method using TA as one of the raw materials, which may effectively inhibit amyloid fibril aggregation and disaggregate mature fibril. The fluorescent property of TACDs were modulated by adjusting the ratio of TA to o-phenylenediamine (oPD), and TACDs fabricated with the precursor ratio as 1:1 showed the best fluorescent property. Circular dichroism spectra (CD) showed that the structure of ß-sheet decreased as the concentration of TACDs increased. The inhibition efficiency, as confirmed by thioflavin T (ThT) and transmission electron microscopy (TEM), is extraordinary at 98.16%, whereas disaggregation efficiency is noteworthy at 97.97%, and the disaggregated lysozyme fibrils did not reaggregate after 7 days. More critically, TACDs can also alleviate the cellular toxicity caused by Aß fibrils and improve cell viability. This work offers a new perspective on the design of scavengers for amyloid plaques.


Assuntos
Carbono , Agregados Proteicos , Taninos , Taninos/química , Taninos/farmacologia , Carbono/química , Humanos , Agregados Proteicos/efeitos dos fármacos , Muramidase/química , Muramidase/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Pontos Quânticos/química , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Amiloide/química , Amiloide/metabolismo , Fenilenodiaminas/química , Fenilenodiaminas/farmacologia , Animais , Polifenóis
10.
PLoS One ; 19(9): e0309416, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39255305

RESUMO

Age-related neurodegenerative disorders like Alzheimer's disease (AD) and Parkinson's disease (PD) are characterized by deposits of protein aggregates, or amyloid, in various regions of the brain. Historically, aggregation of a single protein was observed to be correlated with these different pathologies: tau in AD and α-synuclein (αS) in PD. However, there is increasing evidence that the pathologies of these two diseases overlap, and the individual proteins may even promote each other's aggregation. Both tau and αS are intrinsically disordered proteins (IDPs), lacking stable secondary and tertiary structure under physiological conditions. In this study we used a combination of biochemical and biophysical techniques to interrogate the interaction of tau with both soluble and fibrillar αS. Fluorescence correlation spectroscopy (FCS) was used to assess the interactions of specific domains of fluorescently labeled tau with full length and C-terminally truncated αS in both monomer and fibrillar forms. We found that full-length tau as well as individual tau domains interact with monomer αS weakly, but this interaction is much more pronounced with αS aggregates. αS aggregates also mildly slow the rate of tau aggregation, although not the final degree of aggregation. Our findings suggest that co-occurrence of tau and αS in disease are more likely to occur through monomer-fiber binding interactions, rather than monomer-monomer or co-aggregation.


Assuntos
alfa-Sinucleína , Proteínas tau , alfa-Sinucleína/metabolismo , alfa-Sinucleína/química , Proteínas tau/metabolismo , Proteínas tau/química , Humanos , Ligação Proteica , Agregados Proteicos , Amiloide/metabolismo , Amiloide/química , Espectrometria de Fluorescência , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Agregação Patológica de Proteínas/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia
11.
Cells ; 13(17)2024 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-39273071

RESUMO

Alkaptonuria (AKU) is a rare autosomal recessive metabolic disorder caused by mutations in the homogentisate 1,2-dioxygenase (HGD) gene, leading to the accumulation of homogentisic acid (HGA), causing severe inflammatory conditions. Recently, the presence of serum amyloid A (SAA) has been reported in AKU tissues, classifying AKU as novel secondary amyloidosis; AA amyloidosis is characterized by the extracellular tissue deposition of fibrils composed of fragments of SAA. AA amyloidosis may complicate several chronic inflammatory conditions, like rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease, chronic infections, neoplasms, etc. Treatments of AA amyloidosis relieve inflammatory disorders by reducing SAA concentrations; however, no definitive therapy is currently available. SAA regulation is a crucial step to improve AA secondary amyloidosis treatments. Here, applying a comprehensive in vitro and in silico approach, we provided evidence that HGA is a disruptor modulator of SAA, able to enhance its polymerization, fibril formation, and aggregation upon SAA/SAP colocalization. In silico studies deeply dissected the SAA misfolding molecular pathway and SAA/HGA binding, suggesting novel molecular insights about it. Our results could represent an important starting point for identifying novel therapeutic strategies in AKU and AA secondary amyloidosis-related diseases.


Assuntos
Alcaptonúria , Ácido Homogentísico , Proteína Amiloide A Sérica , Alcaptonúria/metabolismo , Alcaptonúria/patologia , Proteína Amiloide A Sérica/metabolismo , Proteína Amiloide A Sérica/genética , Humanos , Ácido Homogentísico/metabolismo , Agregados Proteicos , Amiloidose/metabolismo , Amiloidose/patologia , Amiloide/metabolismo , Modelos Biológicos , Homogentisato 1,2-Dioxigenase/metabolismo , Homogentisato 1,2-Dioxigenase/genética
12.
Int J Mol Sci ; 25(17)2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39273350

RESUMO

Protein amyloid aggregation is linked with widespread and fatal neurodegenerative disorders as well as several amyloidoses. Insulin, a small polypeptide hormone, is associated with injection-site amyloidosis and is a popular model protein for in vitro studies of amyloid aggregation processes as well as in the search for potential anti-amyloid compounds. Despite hundreds of studies conducted with this specific protein, the procedures used have employed a vast array of different means of achieving fibril formation. These conditions include the use of different solution components, pH values, ionic strengths, and other additives. In turn, this variety of conditions results in the generation of fibrils with different structures, morphologies and stabilities, which severely limits the possibility of cross-study comparisons as well as result interpretations. In this work, we examine the condition-structure relationship of insulin amyloid aggregation under a range of commonly used pH and ionic strength conditions as well as solution components. We demonstrate the correlation between the reaction solution properties and the resulting aggregation kinetic parameters, aggregate secondary structures, morphologies, stabilities and dye-binding modes.


Assuntos
Amiloide , Insulina , Agregados Proteicos , Insulina/química , Insulina/metabolismo , Concentração de Íons de Hidrogênio , Concentração Osmolar , Amiloide/química , Cinética , Humanos , Estrutura Secundária de Proteína , Agregação Patológica de Proteínas
13.
Colloids Surf B Biointerfaces ; 244: 114192, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39226847

RESUMO

Medin amyloid, prevalent in the vessel walls of 97 % of individuals over 50, contributes to arterial stiffening and cerebrovascular dysfunction, yet our understanding of its aggregation mechanism remains limited. Dividing the full-length 50-amino-acid medin peptide into five 10-residue segments, we conducted individual investigations on each segment's self-assembly dynamics via microsecond-timescale atomistic discrete molecular dynamics (DMD) simulations. Our findings showed that medin1-10 and medin11-20 segments predominantly existed as isolated unstructured monomers, unable to form stable oligomers. Medin31-40 exhibited moderate aggregation, forming dynamic ß-sheet oligomers with frequent association and dissociation. Conversely, medin21-30 and medin41-50 segments demonstrated significant self-assembly capability, readily forming stable ß-sheet-rich oligomers. Residue pairwise contact frequency analysis highlighted the critical roles of residues 22-26 and 43-49 in driving the self-assembly of medin21-30 and medin41-50, acting as the ß-sheet core and facilitating ß-strand formation in other regions within medin monomers, expecting to extend to oligomers and fibrils. Regions containing residues 22-26 and 43-49, with substantial self-assembly abilities and assistance in ß-sheet formation, represent crucial targets for amyloid inhibitor drug design against aortic medial amyloidosis (AMA). In summary, our study not only offers deep insights into the mechanism of medin amyloid formation but also provides crucial theoretical and practical guidance for future treatments of AMA.


Assuntos
Amiloide , Simulação de Dinâmica Molecular , Humanos , Amiloide/química , Amiloide/metabolismo , Aorta/metabolismo , Agregados Proteicos , Peptídeos/química , Peptídeos/metabolismo , Conformação Proteica em Folha beta , Antígenos de Superfície/metabolismo , Antígenos de Superfície/química , Sequência de Aminoácidos , Proteínas do Leite
14.
Biophys Chem ; 314: 107319, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39232485

RESUMO

The aggregation of the protein α-synuclein into amyloid deposits is associated with multiple neurological disorders, including Parkinson's disease. Soluble amyloid oligomers are reported to exhibit higher toxicity than insoluble amyloid fibrils, with dimers being the smallest toxic oligomer. Small molecule drugs, such as fasudil, have shown potential in targeting α-synuclein aggregation and reducing its toxicity. In this study, we use atomistic molecular dynamics simulations to demonstrate how fasudil affects the earliest stage of aggregation, namely dimerization. Our results show that the presence of fasudil reduces the propensity for intermolecular contact formation between protein chains. Consistent with previous reports, our analysis confirms that fasudil predominantly interacts with the negatively charged C-terminal region of α-synuclein. However, we also observe transient interactions with residues in the charged N-terminal and hydrophobic NAC regions. Our simulations indicate that while fasudil prominently interacts with the C-terminal region, it is the transient interactions with residues in the N-terminal and NAC regions that effectively block the formation of intermolecular contacts between protein chains and prevent early dimerization of this disordered protein.


Assuntos
1-(5-Isoquinolinasulfonil)-2-Metilpiperazina , Simulação de Dinâmica Molecular , Multimerização Proteica , alfa-Sinucleína , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/análogos & derivados , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/farmacologia , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/química , Humanos , Multimerização Proteica/efeitos dos fármacos , Agregados Proteicos/efeitos dos fármacos
15.
Biol Direct ; 19(1): 77, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39237967

RESUMO

BACKGROUND: GALNTs (UDP-GalNAc; polypeptide N-acetylgalactosaminyltransferases) initiate mucin-type O-GalNAc glycosylation by adding N-GalNAc to protein serine/threonine residues. Abnormalities in O-GalNAc glycosylation are involved in various disorders such as Parkinson's disease (PD), a neurodegenerative disorder. GALNT9 is potentially downregulated in PD patients. METHODS: To determine whether GALNT9 enrichment ameliorates cytotoxicity related to PD-like variations, a pcDNA3.1-GALNT9 plasmid was constructed and transfected into SH-SY5Y cells to establish a GALNT9-overexpressing cell model. RESULTS: Downregulation of GALNT9 and O-GalNAc glycosylation was confirmed in our animal and cellular models of PD-like variations. GALNT9 supplementation greatly attenuated cytotoxicity induced by MPP+ (1-Methyl-4-phenylpyridinium iodide) since it led to increased levels of tyrosine hydroxylase and dopamine, reduced rates of apoptosis, and significantly ameliorated MPP+-induced mitochondrial dysfunction by alleviating abnormal levels of mitochondrial membrane potential and reactive oxygen species. A long-lasting mPTP (mitochondrial permeability transition pores) opening and calcium efflux resulted in significantly lower activity in the cytochrome C-associated apoptotic pathway and mitophagy process, signifying that GALNT9 supplementation maintained neuronal cell health under MPP+ exposure. Additionally, it was found that glycans linked to proteins influenced the formation of protein aggregates containing α-synuclein, and GALNT9 supplement dramatically reduced such insoluble protein aggregations under MPP+ treatment. Glial GALNT9 predominantly appears under pathological conditions like PD-like variations. CONCLUSIONS: GALNT9 enrichment improved cell survival, and glial GALNT9 potentially represents a pathogenic index for PD patients. This study provides insights into the development of therapeutic strategies for the treatment of PD.


Assuntos
1-Metil-4-fenilpiridínio , Mitocôndrias , N-Acetilgalactosaminiltransferases , Polipeptídeo N-Acetilgalactosaminiltransferase , alfa-Sinucleína , N-Acetilgalactosaminiltransferases/metabolismo , N-Acetilgalactosaminiltransferases/genética , alfa-Sinucleína/metabolismo , alfa-Sinucleína/genética , Humanos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Animais , 1-Metil-4-fenilpiridínio/toxicidade , 1-Metil-4-fenilpiridínio/farmacologia , Agregados Proteicos , Doença de Parkinson/metabolismo , Doença de Parkinson/genética , Linhagem Celular Tumoral , Camundongos , Apoptose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Glicosilação , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Masculino
16.
Nat Commun ; 15(1): 7887, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39251571

RESUMO

Importin ß-superfamily nuclear import receptors (NIRs) mitigate mislocalization and aggregation of RNA-binding proteins (RBPs), like FUS and TDP-43, which are implicated in neurodegenerative diseases. NIRs potently disaggregate RBPs by recognizing their nuclear localization signal (NLS). However, disease-causing mutations in NLS compromise NIR binding and activity. Here, we define features that characterize the anti-aggregation activity of NIR and NLS. We find that high binding affinity between NIR and NLS, and optimal NLS location relative to the aggregating domain plays a role in determining NIR disaggregation activity. A designed FUS chimera (FUSIBB), carrying the importin ß binding (IBB) domain, is solubilized by importin ß in vitro, translocated to the nucleus in cultured cells, and downregulates the expression of endogenous FUS. In this study, we posit that guiding the mutual recognition of NLSs and NIRs will aid the development of therapeutics, illustrated by the highly soluble FUSIBB replacing the aggregation-prone endogenous FUS.


Assuntos
Regulação para Baixo , Sinais de Localização Nuclear , Proteína FUS de Ligação a RNA , beta Carioferinas , Proteína FUS de Ligação a RNA/metabolismo , Proteína FUS de Ligação a RNA/genética , Humanos , beta Carioferinas/metabolismo , beta Carioferinas/genética , Núcleo Celular/metabolismo , Ligação Proteica , Células HEK293 , Agregados Proteicos , Células HeLa , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/genética , Transporte Ativo do Núcleo Celular
17.
ACS Chem Neurosci ; 15(18): 3270-3285, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39197832

RESUMO

α-Synuclein (αSyn) aggregates, detected in the biofluids of patients with Parkinson's disease (PD), have the ability to catalyze their own aggregation, leading to an increase in the number and size of aggregates. This self-templated amplification is used by newly developed assays to diagnose Parkinson's disease and turns the presence of αSyn aggregates into a biomarker of the disease. It has become evident that αSyn can form fibrils with slightly different structures, called "strains" or polymorphs, but little is known about their differential reactivity in diagnostic assays. Here, we compared the properties of two well-described αSyn polymorphs. Using single-molecule techniques, we observed that one of the polymorphs had an increased tendency to undergo secondary nucleation and we showed that this could explain the differences in reactivity observed in in vitro seed amplification assay and cellular assays. Simulations and high-resolution microscopy suggest that a 100-fold difference in the apparent rate of growth can be generated by a surprisingly low number of secondary nucleation "points" (1 every 2000 monomers added by elongation). When both strains are present in the same seeded reaction, secondary nucleation displaces proportions dramatically and causes a single strain to dominate the reaction as the major end product.


Assuntos
Doença de Parkinson , alfa-Sinucleína , alfa-Sinucleína/metabolismo , alfa-Sinucleína/química , Humanos , Doença de Parkinson/metabolismo , Imagem Individual de Molécula/métodos , Agregados Proteicos/fisiologia , Agregação Patológica de Proteínas/metabolismo
18.
J Phys Chem B ; 128(36): 8662-8671, 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39205400

RESUMO

Sickle cell disease (SCD) is a monogenic blood disorder associated with a mutation in the hemoglobin subunit ß gene encoding for the ß-globin of normal adult hemoglobin (HbA). This mutation transcribes into a Glu-ß6 → Val-ß6 substitution in the ß-globins, inducing the polymerization of this hemoglobin form (HbS) when in the T-state. Despite advances in stem cell and gene therapy, and the recent approval of a new antisickling drug, therapeutic limitations persist. Herein, we demonstrate through molecular dynamics and umbrella sampling, that (unrestrained) blockage of the hydrophobic pocket involved in the lateral contact of the HbS fibers by 5-mer cyclic peptides, recently proposed as SCD aggregation inhibitors (Neto, V.; J. Med. Chem. 2023, 66, 16062-16074), is enough to turn the dimerization of HbS thermodynamically unfavorable. Among these potential drugs, some exhibit an estimated pocket abandonment probability of around 15-20% within the simulations' time frame, and an impressive specificity toward the mutated Val-ß6. Additionally, we show that the dimerization can be thermodynamically unfavored by blocking a nearby region while the pocket remains vacant. These results are compared with curcumin, an antisickling molecule and a pan-assay interference compound, with a good binding affinity for different proteins and protein domains. Our results confirm the potential of some of these cyclic peptides as antisickling drug candidates to reduce the concentration of aggregation-competent HbS.


Assuntos
Hemoglobina Falciforme , Simulação de Dinâmica Molecular , Peptídeos Cíclicos , Hemoglobina Falciforme/química , Hemoglobina Falciforme/metabolismo , Humanos , Peptídeos Cíclicos/química , Peptídeos Cíclicos/metabolismo , Peptídeos Cíclicos/farmacologia , Agregados Proteicos/efeitos dos fármacos , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/metabolismo , Termodinâmica
19.
ACS Chem Neurosci ; 15(18): 3391-3400, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39215387

RESUMO

The aggregation of the proteins tau and amyloid-ß is a salient feature of Alzheimer's disease, the most common form of neurodegenerative disorders. Upon aggregation, proteins transition from their soluble, monomeric, and functional state into insoluble, fibrillar deposits through a complex process involving a variety of intermediate species of different morphologies, including monomers, toxic oligomers, and insoluble fibrils. To control and direct peptide aggregation, a complete characterization of all species present and an understanding of the molecular processes along the aggregation pathway are essential. However, this is extremely challenging due to the transient nature of oligomers and the complexity of the reaction networks. Therefore, we have employed a combined approach that allows us to probe the structure and kinetics of oligomeric species, following them over time as they form fibrillar structures. Targeting the tau protein peptide segment Ac-PHF6-NH2, which is crucial for the aggregation of the full protein, soft nano-electrospray ionization combined with ion mobility mass spectrometry has been employed to study the kinetics of heparin-induced intact oligomer formation. The oligomers are identified and characterized using high-resolution ion mobility mass spectrometry, demonstrating that the addition of heparin does not alter the structure of the oligomeric species. The kinetics of fibril formation is monitored through a Thioflavin T fluorescence assay. Global fitting of the kinetic data indicates that secondary nucleation plays a key role in the aggregation of the Ac-PHF6-NH2 tau segment, while the primary nucleation rate is greatly accelerated by heparin.


Assuntos
Proteínas tau , Proteínas tau/metabolismo , Proteínas tau/química , Humanos , Cinética , Heparina/química , Espectrometria de Massas por Ionização por Electrospray , Agregados Proteicos/fisiologia
20.
ACS Appl Mater Interfaces ; 16(32): 41843-41854, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39092532

RESUMO

Oxidative degradation of the pathogenic amyloid-ß-peptide (Aß) aggregation is an effective and promising method to treat Alzheimer's disease under light irradiation. However, the limited penetration of external light sources into deep tissues has hindered the development of this treatment. Therefore, we have designed an unprecedented chemiluminescence-initiated photodynamic therapy system to replace external laser irradiation, primarily composed of d-glucose-based polyoxalate (G-poly(oxalate)), the novel photosensitizer (BD-Se-QM), and bis [2,4,5-trichloro-6-(pentoxy-carbonyl) phenyl] ester. BD-Se-QM possesses excellent singlet oxygen (1O2) generation efficiency and the ability to photooxidize Aß1-42 aggregates under white light. G-poly(oxalate) not only helps the nanosystem to cross the blood-brain barrier but also has sufficient oxalate ester groups to significantly enhance the efficiency of chemiluminescence resonance energy transfer. The oxalate ester groups in BD-Se-QM/NPs can chemically react with H2O2 to produce high-energy intermediates that activate BD-Se-QM, which can generate 1O2 to inhibit Aß1-42 aggregates and also promote microglial uptake of Aß1-42, reducing the Aß1-42-induced neurotoxicity. The chemically stimulated nanoplatform not only solves the drug delivery problem but also eliminates the need for external light sources. We anticipate that this chemically excited nanosystem could also be used for targeted delivery of other small molecule drugs.


Assuntos
Peptídeos beta-Amiloides , Oxirredução , Fragmentos de Peptídeos , Fármacos Fotossensibilizantes , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Fotoquimioterapia , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Humanos , Animais , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Luz , Peróxido de Hidrogênio/química , Agregados Proteicos/efeitos dos fármacos , Camundongos
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