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1.
Commun Biol ; 6(1): 1081, 2023 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-37875551

RESUMO

Protein-protein interactions (PPIs) are critical for biological processes and predicting the sites of these interactions is useful for both computational and experimental applications. We present a Structure-agnostic Language Transformer and Peptide Prioritization (SaLT&PepPr) pipeline to predict interaction interfaces from a protein sequence alone for the subsequent generation of peptidic binding motifs. Our model fine-tunes the ESM-2 protein language model (pLM) with a per-position prediction task to identify PPI sites using data from the PDB, and prioritizes motifs which are most likely to be involved within inter-chain binding. By only using amino acid sequence as input, our model is competitive with structural homology-based methods, but exhibits reduced performance compared with deep learning models that input both structural and sequence features. Inspired by our previous results using co-crystals to engineer target-binding "guide" peptides, we curate PPI databases to identify partners for subsequent peptide derivation. Fusing guide peptides to an E3 ubiquitin ligase domain, we demonstrate degradation of endogenous ß-catenin, 4E-BP2, and TRIM8, and highlight the nanomolar binding affinity, low off-targeting propensity, and function-altering capability of our best-performing degraders in cancer cells. In total, our study suggests that prioritizing binders from natural interactions via pLMs can enable programmable protein targeting and modulation.


Assuntos
Peptídeos , Proteínas , Peptídeos/metabolismo , Sequência de Aminoácidos , Ubiquitina-Proteína Ligases/metabolismo
2.
Mol Cell ; 83(17): 3123-3139.e8, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37625406

RESUMO

How the essential eukaryotic chaperonin TRiC/CCT assembles from eight distinct subunits into a unique double-ring architecture remains undefined. We show TRiC assembly involves a hierarchical pathway that segregates subunits with distinct functional properties until holocomplex (HC) completion. A stable, likely early intermediate arises from small oligomers containing CCT2, CCT4, CCT5, and CCT7, contiguous subunits that constitute the negatively charged hemisphere of the TRiC chamber, which has weak affinity for unfolded actin. The remaining subunits CCT8, CCT1, CCT3, and CCT6, which comprise the positively charged chamber hemisphere that binds unfolded actin more strongly, join the ring individually. Unincorporated late-assembling subunits are highly labile in cells, which prevents their accumulation and premature substrate binding. Recapitulation of assembly in a recombinant system demonstrates that the subunits in each hemisphere readily form stable, noncanonical TRiC-like HCs with aberrant functional properties. Thus, regulation of TRiC assembly along a biochemical axis disfavors the formation of stable alternative chaperonin complexes.


Assuntos
Chaperonina com TCP-1 , Actinas , Chaperonina com TCP-1/química , Chaperonina com TCP-1/metabolismo , Humanos , Animais
3.
Nat Commun ; 14(1): 3514, 2023 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-37316535

RESUMO

Here we describe a facile and robust genetic selection for isolating full-length IgG antibodies from combinatorial libraries expressed in the cytoplasm of redox-engineered Escherichia coli cells. The method is based on the transport of a bifunctional substrate comprised of an antigen fused to chloramphenicol acetyltransferase, which allows positive selection of bacterial cells co-expressing cytoplasmic IgGs called cyclonals that specifically capture the chimeric antigen and sequester the antibiotic resistance marker in the cytoplasm. The utility of this approach is first demonstrated by isolating affinity-matured cyclonal variants that specifically bind their cognate antigen, the leucine zipper domain of a yeast transcriptional activator, with subnanomolar affinities, which represent a ~20-fold improvement over the parental IgG. We then use the genetic assay to discover antigen-specific cyclonals from a naïve human antibody repertoire, leading to the identification of lead IgG candidates with affinity and specificity for an influenza hemagglutinin-derived peptide antigen.


Assuntos
Bioensaio , Imunoglobulina G , Humanos , Imunoglobulina G/genética , Citoplasma , Citosol , Escherichia coli/genética , Saccharomyces cerevisiae
4.
ACS Cent Sci ; 9(4): 787-804, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37122450

RESUMO

Glycoengineered bacteria have emerged as a cost-effective platform for rapid and controllable biosynthesis of designer conjugate vaccines. However, little is known about the engagement of such conjugates with naïve B cells to induce the formation of germinal centers (GC), a subanatomical microenvironment that converts naïve B cells into antibody-secreting plasma cells. Using a three-dimensional biomaterials-based B-cell follicular organoid system, we demonstrate that conjugates triggered robust expression of hallmark GC markers, B cell receptor clustering, intracellular signaling, and somatic hypermutation. These responses depended on the relative immunogenicity of the conjugate and correlated with the humoral response in vivo. The occurrence of these mechanisms was exploited for the discovery of high-affinity antibodies against components of the conjugate on a time scale that was significantly shorter than for typical animal immunization-based workflows. Collectively, these findings highlight the potential of synthetic organoids for rapidly predicting conjugate vaccine efficacy as well as expediting antigen-specific antibody discovery.

5.
J Virol ; 97(1): e0133122, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36475765

RESUMO

Oropouche virus (OROV; genus Orthobunyavirus) is the etiological agent of Oropouche fever, a debilitating febrile illness common in South America. We used recombinant expression of the OROV M polyprotein, which encodes the surface glycoproteins Gn and Gc plus the nonstructural protein NSm, to probe the cellular determinants for OROV assembly and budding. Gn and Gc self-assemble and are secreted independently of NSm. Mature OROV Gn has two predicted transmembrane domains that are crucial for glycoprotein translocation to the Golgi complex and glycoprotein secretion, and unlike related orthobunyaviruses, both transmembrane domains are retained during Gn maturation. Disruption of Golgi function using the drugs brefeldin A and monensin inhibits glycoprotein secretion. Infection studies have previously shown that the cellular endosomal sorting complexes required for transport (ESCRT) machinery is recruited to Golgi membranes during OROV assembly and that ESCRT activity is required for virus secretion. A dominant-negative form of the ESCRT-associated ATPase VPS4 significantly reduces recombinant OROV glycoprotein secretion and blocks virus release from infected cells, and VPS4 partly colocalizes with OROV glycoproteins and membranes costained with Golgi markers. Furthermore, immunoprecipitation and fluorescence microscopy experiments demonstrate that OROV glycoproteins interact with the ESCRT-III component CHMP6, with overexpression of a dominant-negative form of CHMP6 significantly reducing OROV glycoprotein secretion. Taken together, our data highlight differences in M polyprotein processing across orthobunyaviruses, indicate that Golgi and ESCRT function are required for glycoprotein secretion, and identify CHMP6 as an ESCRT-III component that interacts with OROV glycoproteins. IMPORTANCE Oropouche virus causes Oropouche fever, a debilitating illness common in South America that is characterized by high fever, headache, myalgia, and vomiting. The tripartite genome of this zoonotic virus is capable of reassortment, and there have been multiple epidemics of Oropouche fever in South America over the last 50 years, making Oropouche virus infection a significant threat to public health. However, the molecular characteristics of this arbovirus are poorly understood. We developed a recombinant protein expression system to investigate the cellular determinants of OROV glycoprotein maturation and secretion. We show that the proteolytic processing of the M polypeptide, which encodes the surface glycoproteins (Gn and Gc) plus a nonstructural protein (NSm), differs between OROV and its close relative Bunyamwera virus. Furthermore, we demonstrate that OROV M glycoprotein secretion requires the cellular endosomal sorting complexes required for transport (ESCRT) membrane-remodeling machinery and identify that the OROV glycoproteins interact with the ESCRT protein CHMP6.


Assuntos
Infecções por Bunyaviridae , Complexos Endossomais de Distribuição Requeridos para Transporte , Glicoproteínas de Membrana , Orthobunyavirus , Proteínas Virais , Humanos , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Orthobunyavirus/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo
6.
REVISA (Online) ; 12(2)2023.
Artigo em Português | LILACS | ID: biblio-1437541

RESUMO

Na definição padrão da medicina a nocicepção ou algesia é a transdução, condução e processamento de sinais nervosos aferentes gerados por nociceptores estimulados,resultando na percepção da dor. Os sinais de estímulos nocivos (mecânicos, térmicos ou químicos) são transmitidos principalmente através de dois tipos de nervos. As terminações nervosas das pequenas fibras mielinizadas a delta e as fibras C não mielinizadas estão localizadas na pele, tecido subcutâneo, periósteo, articulações, músculos e vísceras. As fibras beta mielinizadas, as maiores, normalmente transmitem estímulos não nocivos, como toque, vibração, pressão, movimento e propriocepção. No entanto, a entrada não nociva dessas fibras pode ser incorretamente processada em um sistema nervoso central alterado, resultando na percepção da dor (alodinia).


Assuntos
Dor , Psicoterapia , Fibras Nervosas Amielínicas , Dor Aguda , Dor Crônica , Modelos Biopsicossociais , Fibras Nervosas Mielinizadas
7.
Mundo saúde (Impr.) ; 47: e13672022, 2023.
Artigo em Inglês, Português | LILACS-Express | LILACS | ID: biblio-1418448

RESUMO

O consumo alimentar atual, caracterizado pelo aumento da ingestão de alimentos de alta densidade calórica e baixo valor nutricional pode influenciar negativamente no estado nutricional e surgimento de agravos à saúde. Este estudo teve como objetivo avaliar a qualidade da dieta e fatores associados em pacientes adultos e idosos atendidos num ambulatório de nutrição. Trata-se de um estudo transversal realizado de maio a outubro de 2021 no ambulatório de nutrição do Instituto de Medicina Integral Prof. Fernando Figueira em Recife, Pernambuco. Foram coletadas as informações do perfil sociodemográfico e econômico, estilo de vida, variáveis clínicas e estado nutricional, no momento do atendimento nutricional (primeira consulta e/ou consulta de acompanhamento). A avaliação do consumo alimentar foi realizada por meio da análise do Índice de Qualidade da Dieta Revisado (IQDR). A amostra foi composta por 102 pacientes, e foi evidenciada uma maior frequência de excesso de peso/obesidade e risco cardiovascular muito elevado. Com relação ao IQDR, 72,6% da amostra apresentam dieta saudável. O tempo de acompanhamento foi correlacionado positivamente com a qualidade da dieta (ρ 0,199; p<0,045); e quanto à glicemia de jejum, houve uma correlação negativa com o consumo de cereais totais (ρ -0,229; p<0,050), e positiva com o consumo de leite e derivados (ρ0,265; p<0,023). No que se refere às variáveis antropométricas, evidenciou-se correlações negativas com o consumo de hortifrútis e cereais integrais. O consumo alimentar é considerado complexo e necessita da avaliação dos fatores que possam interferir no mesmo. O acompanhamento nutricional, a modificação e a melhora da qualidade da alimentação, favorecem à adoção de um estilo de vida mais saudável, relacionando-se com a prevenção e/ou o controle das doenças crônicas não transmissíveis e suas complicações.


Current food consumption, characterized by increased intake of high-density foods and low nutritional value can negatively influence nutritional status and the emergence of health problems. This study aimed to evaluate the quality of the diet and associated factors in adult and elderly patients treated in a nutrition outpatient clinic. This is a cross-sectional study conducted from May to October 2021 at the Nutrition Outpatient Unit of the Fernando Figueira Institute of Integral Medicine in Recife, Pernambuco. The information of the sociodemographic and economic profile, lifestyle, clinical variables, and nutritional status was collected at the time of nutritional consultation (first consultation and/or follow-up consultation). The evaluation of food consumption was performed through the analysis of the Diet Quality Index - Revised (DQI-R). The sample consisted of 102 patients, and there was a higher frequency of overweight/obesity and very high cardiovascular risk. Regarding DQI-R, 72.6% of the sample has a healthy diet. The follow-up time was positively correlated with the quality of the diet (ρ 0.199; p <0.045); and regarding fasting blood glucose, there was a negative correlation with the consumption of total cereals (ρ -0.229; p <0.050) and a positive correlation with the consumption of milk and derivatives (ρ 0.265; p <0.023). Regarding anthropometric variables, negative correlations with the consumption of whole grains and cereals was demonstrated. Food consumption is considered complex and requires the evaluation of factors that may interfere with it. Nutritional monitoring, modifying, and improving the quality of food, favors the adoption of a healthier lifestyle, which relates to the prevention and/or control of chronic non-communicable diseases and their complications.

8.
Annu Rev Biomed Data Sci ; 5: 67-94, 2022 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-35472290

RESUMO

The formation of protein complexes is crucial to most biological functions. The cellular mechanisms governing protein complex biogenesis are not yet well understood, but some principles of cotranslational and posttranslational assembly are beginning to emerge. In bacteria, this process is favored by operons encoding subunits of protein complexes. Eukaryotic cells do not have polycistronic mRNAs, raising the question of how they orchestrate the encounter of unassembled subunits. Here we review the constraints and mechanisms governing eukaryotic co- and posttranslational protein folding and assembly, including the influence of elongation rate on nascent chain targeting, folding, and chaperone interactions. Recent evidence shows that mRNAs encoding subunits of oligomeric assemblies can undergo localized translation and form cytoplasmic condensates that might facilitate the assembly of protein complexes. Understanding the interplay between localized mRNA translation and cotranslational proteostasis will be critical to defining protein complex assembly in vivo.


Assuntos
Biossíntese de Proteínas , Dobramento de Proteína , Chaperonas Moleculares/genética , Biossíntese de Proteínas/genética , RNA Mensageiro/genética , Saccharomyces cerevisiae/genética
9.
Nanomaterials (Basel) ; 10(6)2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32599744

RESUMO

Removal of azo and diazo dye content from textile industry wastewaters is crucial due to their environmental impact. Here, we report on the use of the fungal laccase from Pycnoporus sanguineus CS43 immobilized on silica nanoparticles and entrapped in textile-based filters for the degradation of Congo Red. Laccase immobilization and synthesis of the nanocomposites were carried out by two different methods, one in the presence of acetone and the second using water as solvent. This led to a change in the hydrophobicity of the obtained biofilters. Successful preparation of the nanocomposites was confirmed via FTIR spectroscopy. Changes in the secondary structure of the enzyme were inspected through the second derivative of the FTIR spectra. Six different types of filter were fabricated and tested in a continuous flow bioreactor in terms of their decolorization capabilities of Congo Red. The results indicate removal efficiencies that approached 40% for enzymes immobilized on the more hydrophobic supports. Backscattered electron (BSE) images of the different filters were obtained before and after the decolorization process. Percentage of decolorization and activity loss were determined as a function of time until a plateau in decolorization activity was reached. Experimental data was used to recreate the decolorization process in COMSOL Multiphysics® (Stockholm, Sweden). These simulations were used to determine the proper combination of parameters to maximize decolorization. Our findings suggest that the treatment of textile-based filters with immobilized laccase in conjunction with hydrophobic nanocomposites provides a suitable avenue to achieve more efficient laccase dye decolorization (39%) than that obtained with similar filters treated only with free laccase (8%). Filters treated with silica-based nanocomposites and immobilized laccases showed an increase in their decolorization capability, probably due to changes in their wetting phenomena.

10.
Viruses ; 12(7)2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32708342

RESUMO

Oropouche orthobunyavirus (OROV) is an emerging arbovirus with a high potential of dissemination in America. Little is known about the role of peripheral blood mononuclear cells (PBMC) response during OROV infection in humans. Thus, to evaluate human leukocytes susceptibility, permissiveness and immune response during OROV infection, we applied RNA hybridization, qRT-PCR and cell-based assays to quantify viral antigens, genome, antigenome and gene expression in different cells. First, we observed OROV replication in human leukocytes lineages as THP-1 monocytes, Jeko-1 B cells and Jurkat T cells. Interestingly, cell viability and viral particle detection are maintained in these cells, even after successive passages. PBMCs from healthy donors were susceptible but the infection was not productive, since neither antigenome nor infectious particle was found in the supernatant of infected PBMCs. In fact, only viral antigens and small quantities of OROV genome were detected at 24 hpi in lymphocytes, monocytes and CD11c+ cells. Finally, activation of the Interferon (IFN) response was essential to restrict OROV replication in human PBMCs. Increased expression of type I/III IFNs, ISGs and inflammatory cytokines was detected in the first 24 hpi and viral replication was re-established after blocking IFNAR or treating cells with glucocorticoid. Thus, in short, our results show OROV is able to infect and remain in low titers in human T cells, monocytes, DCs and B cells as a consequence of an effective IFN response after infection, indicating the possibility of leukocytes serving as a trojan horse in specific microenvironments during immunosuppression.


Assuntos
Infecções por Bunyaviridae/metabolismo , Leucócitos Mononucleares/virologia , Orthobunyavirus , RNA Viral/metabolismo , Citometria de Fluxo , Imunofluorescência , Genoma Viral/genética , Humanos , Microscopia Confocal , Orthobunyavirus/genética , Orthobunyavirus/metabolismo , Orthobunyavirus/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Replicação Viral
11.
Drug Deliv ; 27(1): 864-875, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32515999

RESUMO

Therapeutic drugs for Alzheimer's disease have been extensively studied due to its recurrence and abundance among neurodegenerative diseases. It is thought that the accumulation of amyloid precursor protein (APP) products, a consequence of an up-regulation of the ß-site APP-cleaving enzyme 1 (BACE1), is the main triggering mechanism during the early stages of the disease. This study aims to explore the ability of a multifunctional conjugate based on magnetite nanoparticles for the cellular delivery of siRNA against the expression of the BACE1 gene. We immobilized the siRNA strand on PEGylated magnetite nanoparticles and investigated the effects on biocompatibility and efficacy of the conjugation. Similarly, we co-immobilized the translocating protein OmpA on PEGylated nanoparticles to enhance cellular uptake and endosomal escape. BACE1 suppression was statistically significant in HFF-1 cells, without any presence of a cytotoxic effect. The delivery of the nanoconjugate was achieved through endocytosis pathways, where endosome formation was likely escaped due to the proton-sponge effect characteristic of PEGylated nanoparticles or mainly by direct translocation in the case of OmpA/PEGylated nanoparticles.


Assuntos
Doença de Alzheimer , Secretases da Proteína Precursora do Amiloide/genética , Ácido Aspártico Endopeptidases/genética , Inativação Gênica , Nanopartículas de Magnetita/uso terapêutico , RNA Interferente Pequeno/uso terapêutico , Doença de Alzheimer/genética , Doença de Alzheimer/terapia , Animais , Encéfalo/metabolismo , Linhagem Celular , Endocitose/fisiologia , Endossomos/metabolismo , Técnicas de Transferência de Genes , Humanos , Teste de Materiais
12.
Polymers (Basel) ; 12(6)2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32560036

RESUMO

Polymeric microcapsules with the fungal laccase from Pycnoporus sanguineus CS43 may represent an attractive avenue for the removal or degradation of dyes from wastewaters. Microcapsules of alginate/chitosan (9.23 ± 0.12 µm) and poly(styrenesulfonate) (PSS) (9.25 ± 0.35 µm) were synthesized and subsequently tested for catalytic activity in the decolorization of the diazo dye Congo Red. Successful encapsulation into the materials was verified via confocal microscopy of labeled enzyme molecules. Laccase activity was measured as a function of time and the initial reaction rates were recovered for each preparation, showing up to sevenfold increase with respect to free laccase. The ability of substrates to diffuse through the pores of the microcapsules was evaluated with the aid of fluorescent dyes and confocal microscopy. pH and thermal stability were also measured for encapsulates, showing catalytic activity for pH values as low as 4 and temperatures of about 80 °C. Scanning electron microscope (SEM) analyses demonstrated the ability of PSS capsules to avoid accumulation of byproducts and, therefore, superior catalytic performance. This was corroborated by the direct observation of substrates diffusing in and out of the materials. Compared with our PSS preparation, alginate/chitosan microcapsules studied by others degrade 2.6 times more dye, albeit with a 135-fold increase in units of enzyme per mg of dye. Similarly, poly(vinyl) alcohol microcapsules from degrade 1.7 times more dye, despite an eightfold increase in units of enzyme per mg of dye. This could be potentially beneficial from the economic viewpoint as a significantly lower amount of enzyme might be needed for the same decolorization level achieved with similar encapsulated systems.

13.
ACS Biomater Sci Eng ; 6(1): 415-424, 2020 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33463215

RESUMO

Outer membrane protein A (OmpA) has been extensively studied in Gram-negative bacteria due to its relevance in the adhesion of pathogens to host cells and its surfactant capabilities. It consists of a hydrophobic ß-barrel domain and a hydrophilic periplasmic domain, that confers OmpA an amphiphilic structure. This study aims to elucidate the capacity of Escherichia coli OmpA to translocate liposomal membranes and serve as a potential cell-penetrating vehicle. We immobilized OmpA on magnetite nanoparticles and investigated the possible functional changes exhibited by OmpA after immobilization. Liposomal intake was addressed using egg lecithin liposomes as a model, where magnetite-OmpA nanobioconjugates were able to translocate the liposomal membrane and caused a disruptive effect when subjected to a magnetic field. Nanobioconjugates showed both low cytotoxicity and hemolytic tendency. Additional interactions within the intracellular space led to altered viability results via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Confocal microscopy images revealed that immobilized nanoparticles effectively enter the cytoplasm of THP-1 and Vero cells by different routes, and, subsequently, some escape endosomes, lysosomes, and other intracellular compartments with relatively high efficiencies. This was demonstrated by co-localization analyses with LysoTracker green that showed Pearson correlations of about 80 and 28%.


Assuntos
Proteínas da Membrana Bacteriana Externa , Óxido Ferroso-Férrico , Animais , Chlorocebus aethiops , Endossomos , Células Vero
14.
Arch Pharm (Weinheim) ; 353(2): e1900241, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31840866

RESUMO

Nineteen 3,5-disubstituted-isoxazole analogs were synthesized based on nitrofuran scaffolds, by a [3 + 2] cycloaddition reaction between terminal acetylenes and 5-nitrofuran chloro-oxime. The compounds were obtained in moderate to very good yields (45-91%). The antileishmanial activity was assayed against the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. Alkylchlorinated compounds 14p-r were active on both the promastigote and amastigote forms, with emphasis on compound 14p, which showed strong activity against the amastigote form (IC50 = 0.6 µM and selectivity index [SI] = 5.2). In the alkyl series, compound 14o stands out with an IC50 = 8.5 µM and SI = 8.0 on the amastigote form. In the aromatic series, the most active compounds were those containing electron-donor groups, such as trimethoxy isoxazole 14g (IC50 = 1.2 µM and SI = 20.2); compound 14h, with IC50 = 7.0 µM and SI = 6.1; and compound 14j containing the 4-SCH3 group, with IC50 = 5.7 µM and SI = 10.2. In addition, the antifungal activity of 19 nitrofuran isoxazoles was evaluated against five strains of Candida (C. albicans, C. parapsilosis, C. krusei, C. tropicalis, and C. glabrata). Eleven isoxazole derivatives were active against C. parapsilosis, and compound 14o was found to be the most active (minimal inhibitory concentration [MIC] = 3.4 µM) for this strain. Compound 14p was active against all the strains tested, with an MIC = 17.5 µM for C. glabrata, lower than that of the fluconazole used as the reference drug.


Assuntos
Antifúngicos/farmacologia , Antiprotozoários/farmacologia , Candida/efeitos dos fármacos , Desenho de Fármacos , Isoxazóis/farmacologia , Leishmania/efeitos dos fármacos , Nitrofuranos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Antiprotozoários/síntese química , Antiprotozoários/química , Relação Dose-Resposta a Droga , Isoxazóis/síntese química , Isoxazóis/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Nitrofuranos/química , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade
15.
Sci Rep ; 9(1): 17206, 2019 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-31748561

RESUMO

The genus Paracoccidioides consist of dimorphic fungi geographically limited to the subtropical regions of Latin America, which are responsible for causing deep systemic mycosis in humans. However, the molecular mechanisms by which Paracoccidioides spp. causes the disease remain poorly understood. Paracoccidioides spp. harbor genes that encode proteins involved in host cell interaction and mitochondrial function, which together are required for pathogenicity and mediate virulence. Previously, we identified TufM (previously known as EF-Tu) in Paracoccidioides brasiliensis (PbTufM) and suggested that it may be involved in the pathogenicity of this fungus. In this study, we examined the effects of downregulating PbTUFM using a silenced strain with a 55% reduction in PbTUFM expression obtained by antisense-RNA (aRNA) technology. Silencing PbTUFM yielded phenotypic differences, such as altered translation elongation, respiratory defects, increased sensitivity of yeast cells to reactive oxygen stress, survival after macrophage phagocytosis, and reduced interaction with pneumocytes. These results were associated with reduced virulence in Galleria mellonella and murine infection models, emphasizing the importance of PbTufM in the full virulence of P. brasiliensis and its potential as a target for antifungal agents against paracoccidioidomycosis.


Assuntos
Comunicação Celular , Interações Hospedeiro-Patógeno , Paracoccidioides/patogenicidade , Paracoccidioidomicose/microbiologia , Fator Tu de Elongação de Peptídeos/metabolismo , Fatores de Virulência/metabolismo , Virulência , Animais , Regulação para Baixo , Macrófagos/imunologia , Macrófagos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Paracoccidioides/metabolismo , Paracoccidioidomicose/metabolismo , Fagocitose
16.
Chem Biol Drug Des ; 94(6): 2004-2012, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31444858

RESUMO

Isoxazole analogues derived from the neolignans veraguensin, grandisin, and machilin G were previously synthesized with different substitution patterns through the bioisosterism strategy. These compounds were tested on intracellular amastigotes of Leishmania (Leishmania) amazonensis; the derivatives proved to be active against intracellular amastigotes, with IC50 values ranging from 0.4 to 25 µM. The most active analogues were 4', 14', 15', and 18', with IC50 values of 0.9, 0.4, 0.7, and 1.4 µM, respectively, showing high selectivity indexes (SI = 277.0; 625.0; 178.5 and 357.1). Overall, the isoxazole analogues did not induce nitric oxide (NO) production by infected cells; there was no evidence that NO influences the antileishmanial mechanism of action, except for compound 4'. Trimethoxy groups as substituents seemed to be critical for antileishmanial activity. The SAR study demonstrated that the isoxazole compounds were more active than 1,2,3-triazole compounds with the same substitution pattterns, demonstrating the importance of the bioisosterism strategy in drug design.


Assuntos
Antiprotozoários/farmacologia , Furanos/química , Isoxazóis/química , Leishmania/efeitos dos fármacos , Lignanas/química , Triazóis/química , Animais , Antiprotozoários/química , Desenho de Fármacos , Feminino , Concentração Inibidora 50 , Isoxazóis/farmacologia , Leishmania/crescimento & desenvolvimento , Estágios do Ciclo de Vida/efeitos dos fármacos , Macrófagos Peritoneais/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Relação Estrutura-Atividade
17.
Biosci. j. (Online) ; 35(1): 333-346, jan./fev. 2019. ilus
Artigo em Inglês | LILACS | ID: biblio-1048587

RESUMO

Young patients are increasingly concerned with smile aesthetics, resulting in the early visit to the dental office. It is of great importance that professionals such as orthodontists, pediatric dentists, and general practitioners are aware of the potential changes in positioning and development that may compromise aesthetics, considering they may prevent future complex orthodontic treatments. This case report describes the treatment of a patient aged 9 years and 4 months, who complained at assessment about the size and position of maxillary incisors. Clinically, the patient presented atresic maxilla and eruption of teeth 12 and 22. The poor positioning of tooth 22 alerted for the potential retention of tooth 23. A two-phase treatment was proposed, including an intercepting phase and a corrective phase. In the intercepting phase, rapid maxillary expansion (RME) was performed, which increased the room for eruption of tooth 23 and prevented the collapse of tooth 22. After the activation period, the Haas expander was locked and removed six months later. Twenty-five months after the removal, the second phase started with fixed corrective orthodontics and traction of tooth 23, for which the enamel was drilled and traction was performed using the segmented technique with a 0.019" x 0.025" Titanium Molybdenum Alloy (TMA) cantilever and anchorage in passive transpalatal arch (PTA). The use of this technique minimizes the side effects on the teeth adjacent to tooth 23 and enamel drilling prevents potential losses of the traction device by detachment. After 4 months of segmented mechanics, the devices were removed and the PTA was maintained. Twenty-six months later, the patient was 14 years and 4 months old, presenting direct subdivision Class III molar relationship, upper and lower crowding, and unsatisfactory relationship between bone bases due to the excessive mandibular growth. A new RME was performed, and after 3 months a Capelozza Pattern III fixed appliance was installed in the lower arch. Additionally, an upper fixed appliance was installed after the RME retention period. One year and 4 months later, the appliances were removed and a maxillary Hawley plate was installed with a 0.6-mm fixed mandibular intercanine arch. The follow-up lasted 3 years and 4 months and the results were maintained, preserving the occlusal and facial characteristics.


A preocupação dos pacientes jovens com a estética do sorriso está cada vez maior, ocasionando na visita precoce ao consultório odontológico. É de grande importância que os profissionais, tanto ortodontistas quanto odontopediatras e clínicos gerais, estejam atentos à possíveis alterações de posicionamento e desenvolvimento que comprometam a estética, visto que isso pode evitar tratamentos ortodônticos complexos no futuro. Este relato de caso descreve o tratamento de uma paciente de 9 anos e 4 meses que na avaliação se queixou do tamanho e posição dos incisivos superiores. Clinicamente apresentou maxila atrésica e dentes 12 e 22 em erupção. O mal posicionamento do dente 22 alertou para possível retenção do dente 23. Um tratamento em duas fases foi proposto: uma fase interceptadora e uma segunda fase corretiva. Na interceptadora foi realizada expansão rápida da maxila (ERM), aumentando o espaço para erupção do dente 23 e evitando colapso com o dente 22. Após o período de ativação, o expansor de Haas foi travado e sua remoção feita seis meses após o travamento. Passados 25 meses da remoção, iniciou-se a segunda fase, com ortodontia fixa corretiva e tracionamento do dente 23. Para o tracionamento, foi feita perfuração no esmalte e tracionamento por meio da técnica segmentada, utilizando cantilever de Titanium Molybdenum Alloy (TMA) 0,019" x 0,025" e ancoragem em barra transpalatina passiva (BTP). A utilização desta técnica minimiza efeitos colaterais aos dentes adjacentes ao 23 e a perfuração de esmalte evita possíveis perdas do dispositivo de tracionamento por descolagem. Após 4 meses de mecânica segmentada, removeu-se os dispositivos mantendo a BTP. Passados mais 26 meses, a paciente se encontrava com 14 anos 4 meses, relação molar de Classe III subdivisão direita, apinhamento superior e inferior e relação insatisfatória das bases ósseas, devido ao crescimento excessivo da mandíbula. Foi realizada nova ERM, após 3 meses instalou-se aparelho fixo Padrão III de Capelozza no arco inferior e, após o período de contenção da ERM, instalou-se o aparelho fixo superior. Após 1 ano e 4 meses, removeu-se os dispositivos e se instalou uma placa de Hawley superior, com barra fixa intercaninos de 0.6mm no arco inferior. Com acompanhamento de 3 anos e 4 meses, os resultados foram mantidos, preservando ascaracterísticas oclusais e faciais.


Assuntos
Ortodontia , Sorriso , Anormalidades Dentárias , Dente Impactado
18.
Angle Orthod ; 89(1): 71-77, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30230376

RESUMO

OBJECTIVES: To assess reliability and reproducibility of the individual assessment of midpalatal suture maturation in computed tomography among orthodontists and radiologists for potential diagnosis application. MATERIALS AND METHODS: Sixty axial slices from cone-beam computed tomography and multi-slice CT scans of patients aged between 11 and 21 years old (33 females and 27 males) were selected. For the investigation of reliability and reproducibility of the method, two groups of examiners were established. The first group consisted of 11 orthodontists and the second consisted of 10 radiologists. Each group examined the images and performed individual assessment of the midpalatal suture maturation method twice within an interval of 21 days. During the first and second analyses, the sequence of images was randomized to reduce potential bias. Weighted Cohen's kappa was performed to assess inter- and intra-examiners' agreement. The percentage of perfect agreement and the number of stages apart for each disagreement were calculated. The significance level was P < .05. RESULTS: The overall inter-examiner agreement was satisfactory in the first (kappaw: 0.37) and the second (kappaw: 0.34) analyses. Intra-examiner agreement outcomes were similar between orthodontists (kappaw: 0.44) and radiologists (kappaw: 0.41). The percentage of perfect agreement was 43.2%. CONCLUSIONS: The method for individual assessment of midpalatal suture maturation revealed potential reliability and reproducibility. However, the agreement rate observed in the present study was not high enough for a method designed for routine clinical applications.


Assuntos
Suturas Cranianas , Palato , Tomografia Computadorizada por Raios X , Adolescente , Adulto , Criança , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Masculino , Palato/crescimento & desenvolvimento , Reprodutibilidade dos Testes , Adulto Jovem
19.
J Cell Biochem ; 120(4): 6015-6025, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30320934

RESUMO

Ribosomal S6 kinase 1 (S6K1) and S6K2 proteins are effectors of the mammalian target of rapamycin complex 1 pathway, which control the process of protein synthesis in eukaryotes. S6K2 is associated with tumor progression and has a conserved C-terminus polyproline rich motif predicted to be important for S6K2 interactions. It is noteworthy that the translation of proteins containing sequential prolines has been proposed to be dependent of eukaryotic translation initiation factor 5A (eIF5A) translation factor. Therefore, we investigated the importance of polyproline-rich region of the S6K2 for its intrinsic phosphorylation activity, protein-protein interaction and eIF5A role in S6K2 translation. In HeLa cell line, replacing S6K2 polyproline by the homologous S6K1-sequence did not affect its kinase activity and the S6K2 endogenous content was maintained after eIF5A gene silencing, even after near complete depletion of eIF5A protein. Moreover, no changes in S6K2 transcript content was observed, ruling out the possibility of compensatory regulation by increasing the mRNA content. However, in the budding yeast model, we observed that S6K2 production was impaired when compared with S6K2∆Pro, after reduction of eIF5A protein content. These results suggest that although the polyproline region of S6K2 is capable of generating ribosomal stalling, the depletion of eIF5A in HeLa cells seems to be insufficient to cause an expressive decrease in the content of endogenous S6K2. Finally, coimmunoprecipitation assays revealed that the replacement of the polyproline motif of S6K2 alters its interactome and impairs its interaction with RPS6, a key modulator of ribosome activity. These results evidence the importance of S6K2 polyproline motif in the context of S6Ks function.


Assuntos
Fatores de Iniciação de Peptídeos/química , Fatores de Iniciação de Peptídeos/metabolismo , Peptídeos/química , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo , Inativação Gênica , Células HeLa , Humanos , Imunoprecipitação , Espectrometria de Massas , Fatores de Iniciação de Peptídeos/genética , Fosforilação , Reação em Cadeia da Polimerase , Ligação Proteica , Isoformas de Proteínas/genética , Proteínas de Ligação a RNA/genética , Proteínas Quinases S6 Ribossômicas/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Fator de Iniciação de Tradução Eucariótico 5A
20.
Chem Biol Drug Des ; 93(3): 313-324, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30354012

RESUMO

Using bioisosterism as a medicinal chemistry tool, 16 3,5-diaryl-isoxazole analogues of the tetrahydrofuran neolignans veraguensin, grandisin and machilin G were synthesized via 1,3-dipolar cycloaddition reactions, with yields from 43% to 90%. Antitrypanosomatid activities were evaluated against Trypanosoma cruzi, Leishmania (L.) amazonensis and Leishmania (V.) braziliensis. All compounds were selective for the Leishmania genus and inactive against T. cruzi. Isoxazole analogues showed a standard activity on both promastigotes of L. amazonensis and L. braziliensis. The most active compounds were 15, 16 and 19 with IC50 values of 2.0, 3.3 and 9.5 µM against L. amazonensis and IC50 values of 1.2, 2.1 and 6.4 µM on L. braziliensis, respectively. All compounds were noncytotoxic, showing lower cytotoxicity (>250 µM) than pentamidine (78.9 µM). Regarding the structure-activity relationship (SAR), the methylenedioxy group was essential to antileishmanial activity against promastigotes. Replacement of the tetrahydrofuran nucleus by an isoxazole core improved the antileishmanial activity.


Assuntos
Antiprotozoários/química , Desenho de Fármacos , Furanos/química , Isoxazóis/química , Lignanas/química , Animais , Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Concentração Inibidora 50 , Isoxazóis/síntese química , Isoxazóis/farmacologia , Leishmania/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacos
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