Browsing by Author "Breguez, Gustavo Silveira"

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    Avaliação proteômica e caracterização do potencial angiogênico do peptídeo PR-11 e análogos.
    (2016) Breguez, Gustavo Silveira; Andrade, Milton Hércules Guerra de; Borges, William de Castro; Andrade, Milton Hércules Guerra de; Castro, Ieso de Miranda; Cardoso, Leonardo Máximo; Borges, Márcia Helena; Silva, Nilson Penha
    O proteassoma tem sido considerado um potencial alvo farmacológico devido ao seu envolvimento em processos vitais relacionados à proteólise celular, sendo a mais importante entre as vias de degradação. A literatura demonstra que estruturas análogas ao peptídeo PR-11 (RRRPRPPYLPR), que corresponde aos 11 primeiros aminoácidos da porção N-terminal do peptídeo natural PR-39, apresentam uma forte inibição sobre o proteassoma 20S. Inicialmente descoberto por suas propriedades antimicrobianas, os peptídeos desta classe desempenham importantes efeitos anti-inflamatórios e angiogênicos. Apesar da ampla atividade biológica, os estudos moleculares são predominantemente limitados à inibição do proteassoma por estes peptídeos. Dessa forma, este trabalho teve como principais objetivos: avaliar o proteoma de culturas de fibroblastos expostas ao PR-11; identificar possíveis alvos desse peptídeo por sua imobilização em coluna de afinidade e caracterizar o perfil angiogênico do PR-11 e moléculas análogas por meio de implantes subcutâneos de esponjas em camundongos. Os peptídeos PR-11, F12 e C8C15 foram sintetizados empregando-se a estratégia Fmoc em fase sólida, purificados em sistema HPLC e identificados por espectrometria de massas. A estratégia shotgun label-free foi utilizada para avaliar as alterações proteômicas causadas pela exposição de culturas de fibroblastos ao PR-11 a 1 μM durante 2, 6 e 10 horas. Esta abordagem revelou que mais da metade das proteínas diferencialmente expressas identificadas estão relacionadas à sinalização celular, transcrição e tradução. Proteínas diretamente associadas à angiogênese pela regulação ou interação com o HIF-1α foram significativamente alteradas. Além disso, ao menos três proteínas diferencialmente expressas da via do NF-κB relacionam-se a uma resposta anti-inflamatória. Em paralelo, a interação do PR-11 imobilizado com extrato solúvel de fígado de ratos permitiu a identificação de novos ligantes ao peptídeo, destacando-se a gC1qR. Esta proteína está envolvida na internalização celular do peptídeo CGKRK, o qual assemelha-se ao segmento N-terminal do PR-11. Nossos resultados apresentam evidências preliminares de que a proteína gC1qR possa mediar a internalização celular do PR-11. De modo geral, a avaliação histológica das esponjas dos animais tratados com os peptídeos PR-11, F12 e C8C15 demonstra um aumento do perfil proliferativo e maturação do processo angiogênico. Por fim, os dados obtidos neste trabalho apresentam importantes informações para a elucidação dos mecanismos moleculares envolvidos nas atividades biológicas promovidas pelo PR-11 e moléculas similares.
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    Effect of storage on retinol content and total antioxidant capacity of human milk.
    (2019) Chaves, Jaísa Oliveira; Fernandes, Angelica Maria de Freitas; Parreiras, Paola Machado; Breguez, Gustavo Silveira; Passos, Maria Cristina; Cunha, Luciana Rodrigues da; Menezes, Camila Carvalho de
    Purpose – The purpose of this paper is to evaluate the effect of different times and freezing temperatures on the antioxidant activity of raw human milk (HM) and the impact of light by different packaging on retinol level and the antioxidant activity of pasteurized HM. Design/methodology/approach – Donor milks were homogenized to form the pool of the experimental study characterized by the evaluation of the effects of time (0, 2, 4, 8 and 15 days) freezing temperatures (−3°C, −8°C and −18°C) and the interference of the type of packaging on the antioxidant activity and retinol levels of HM. Findings – The existing studies do not reveal the real impact of HM storage conditions adopted by human milk banks (HMB) in Brazil on their compounds, mainly in relation to the effects of temperature and freezing time and the incidence of light on retinol levels and antioxidant activity. In view of the already documented importance of these compounds for the growth, development and health of children, it is extremely important to assess their stability according to the procedures adopted by the banks. It has been observed in this study that lower freezing temperatures (−18°C) further preserve the antioxidant activity. It was found that the amber and transparent vials wrapped with aluminum foil allowed for greater retinol stability of HM, with values of 2.501±0.757 µmol/L and 4.991±0.825 µmol/L, respectively. On the contrary, there was no significant influence on antioxidant activity. Originality/value – It is suggested that HMB store milk at lower temperatures and use glass jars that block the passage of light.
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    Effect of thermosonication on microorganisms, the antioxidant activity and the retinol level of human milk.
    (2020) Parreiras, Paola Machado; Nogueira, Janaina Aparecida Vieira; Cunha, Luciana Rodrigues da; Passos, Maria Cristina; Gomes, Nayara Resende; Breguez, Gustavo Silveira; Falco, Thaís Silva; Bearzoti, Eduardo; Menezes, Camila Carvalho de
    In order to reduce the degradation of naturally-occurring components by conventional heat treatment, alternative processing techniques have been studied to preserve the nutritional properties of processed foods, such as thermosonication. This study evaluates the application of thermosonication for the inactivation of pathogenic microorganisms, and its effect on antioxidant activity and retinol level in donated human milk. We evaluate the effect of thermosonication on Staphylococcus aureus, Escherichia coli, and Salmonella spp. microorganisms in human milk by analyzing the effect of time and temperature of the thermosonication on these microorganisms using a central composite rotatable design. Also evaluated the effects of thermosonication (60 °C/4 min) on antioxidant activity using DPHH (2, 2-diphenyl-1-picrylhydrazyl) free radical and ABTS (2,2′-azino-bis 3- ethylbenzothiazoline-6-sulfonic acid) scavenging methods and on the retinol level in human milk and compared them to the effects of holder pasteurization (62.5 °C/30 min) in vitro. For this evaluation, a pool of the 10 human milk samples was made and distributed 40 mL, from this pool, for two interventions (holder pasteurization and thermosonication) and one control (untreated milk). Both in thermosonication and non-ultra-sound heat treatments, the microorganism counts tended to remain stable at lower temperatures, with the most significant and continuous reductions in thermosonication observed at the points of inflexion of the curves of the adjusted models: at 53.7 °C, 52.0 °C, and 60.9 °C for S. aureus, E. coli, and Salmonella, respectively. Thermosonication also promoted greater decimal reductions of the microorganisms analyzed than heat treatment at 60 °C, 48 °C, and 65 °C for S. aureus, E. coli, and Salmonella, respectively. Holder pasteurization significantly reduced the antioxidant activity when compared to the control, while thermosonication increased it. Retinol level remained stable following both pasteurization and thermosonication. This study could be used to encourage further studies to fill in the remaining gaps for this type of processing on human milk.
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    EPA/DHA and linseed oil have different effects on liver and adipose tissue in rats fed with a high-fat diet.
    (2022) Dias, Bruna Vidal; Gomes, Sttefany Viana; Castro, Maria Laura da Cruz; Carvalho, Luana Cristina Faria; Breguez, Gustavo Silveira; Souza, Débora Maria Soares de; Ramos, Camila de Oliveira; Sant’Ana, Marcella Ramos; Nakandakari, Susana Castelo Branco Ramos; Araujo, Carolina Morais; Guimaraes, Andrea Grabe; Silva, André Talvani Pedrosa da; Carneiro, Cláudia Martins; Cintra, Dennys Esper Corrêa; Costa, Daniela Caldeira
    The incidence of cardiovascular diseases and metabolic disorders has increased worldwide. Clinical and exper- imental research has shown that the consumption of ω-3 FAs can be beneficial to metabolism in several ways, as they can act on metabolic pathways. Our objective was to evaluate the effect of treatment with linseed oil, a vegetable oil rich in alpha-linolenic acid, and EPA and DHA in different proportions (3:1 EPA:DHA, and 1:3 EPA: DHA), on the metabolic disorders induced by a high-fat diet (20 % lipids) in rats for 2 weeks, after 18 weeks of consumption of a high-fat diet. In 18 weeks, the high-fat diet increased blood glucose, systolic blood pressure, triglyceride concentration in the liver and adipose tissue, and impaired insulin sensibility without interfering in the weight of the animals. All treatments were effective in reducing the deposition of hepatic type III collagen, the proportion of ω-6/ω-3 in the liver and WAT (white adipose tissue), the proportion of area/number of adi- pocytes, and the gene expression of the ACC, FAS, and CPT1 enzymes. In addition, treatment with EPA and DHA reduced blood glucose, serum TNF-α concentration, amount of liver fat, degree of microsteatosis and type I collagen deposition in the liver, deposition of type I and III collagen in TA, gene expression of the transcription factor SREBP-1c, and increased hepatic binucleation. EPA in major proportion was more effective in reducing the area of adipocytes, hepatic triglyceride concentration, PPAR-α expression, and WAT fat weight. DHA in a major proportion reduced the concentration of MCP1 in WAT. LO treatment did not have any isolated effects. We concluded that EPA and DHA were more effective in treating metabolic damage than treatment with LO, leading to a more favorable metabolic profile.
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    Exposure of cultured fibroblasts to the peptide PR-11 for the identification of induced proteome alterations and discovery of novel potential ligands.
    (2016) Breguez, Gustavo Silveira; Neves, Leandro Xavier; Rúbio, Karina Taciana Santos; Freitas, Lorran Miranda Andrade de; Faria, Gabriela de Oliveira; Isoldi, Mauro César; Borges, William de Castro; Andrade, Milton Hércules Guerra de
    The PR-11 peptide corresponds to the N-terminal and active region of the endogenously synthesized PR-39 molecule, of porcine origin. It is known to possess various biological effects including antimicrobial properties, angiogenic and anti-inflammatory activities. Apart from its reported activity as a proteasome inhibitor, a more comprehensive understanding of its function, at the molecular level, is still lacking. In this study, we used a label-free shotgun strategy to evaluate the proteomic alterations caused by exposure of cultured fibroblasts to the peptide PR-11. This approach revealed that more than half of the identified moleculeswere related to signalling, transcription and translation. Proteins directly associated to regulation of angiogenesis and interaction with the hypoxia-inducible factor 1-α (HIF-1α) were significantly altered. In addition, at least three differentially expressed molecules of the NF-κB pathway were detected, suggesting an anti-inflammatory property of PR-11. At last, we demonstrated novel potential ligands of PR-11, through its immobilization for affinity chromatography. Among the elutedmolecules, gC1qR, a known complement receptor, appearedmarkedly enriched. This provided preliminary evidence of a PR-11 ligand possibly involved in the internalization of this peptide. Altogether, our findings contributed to a better understanding of the cellular pathways affected by PR-39 derived molecules.
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    Medicamentos anti-hipertensivos utilizados na área rural de Ouro Preto, MG.
    (2007) Silva, Adriana Carneiro; Pereira, Roberta Verciano; Figueiredo, Bárbara de Castro Pimentel; Couto, Wagner Faria; Gramigna, Luísa Leite; Sana, Dandara Emery Morais; Gomes, Rodrigo Saar; Andrade, Graziela de Fátima; Brant, João Francisco de Avelar Caldeira; Breguez, Gustavo Silveira; Silva, Mariana Augusta Resende; Barbeitos, Priscila Oliveira; Junior, Luiz Carlos Pereira; Reis, Levi Eduardo Soares; Jayme, Marisa Ferrareto; Camargo, Rúbia Santos; Franco, Marcelo Nóbile; Amaral, Murilo Sena; Carneiro, Cláudia Martins; Guimarães, Andrea Grabe
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    Prevalence of anxiety, depression, and suicidal ideation symptoms among university students : a systematic review.
    (2020) Paula, Waléria de; Breguez, Gustavo Silveira; Machado, Elaine Leandro; Meireles, Adriana Lúcia
    Several studies have suggested an increase in the prevalence of mental disorders and suicidal ideation among university students. This review aims to determine the current prevalence of university students identified with anxiety, depression, and suicidal ideation symptoms worldwide. After the survey in five electronic databases utilizing the PRISMA guidelines, 48 articles involving 40 countries and 56,816 students were selected. The results showed a prevalence of 24.5% for anxiety symptoms, 26.1% for depression symptoms, and 18.8% for suicidal ideation. Moreover, the prevalence of all these situations was higher in health students than in the general university population. The high prevalence of mental disorders in university students highlights the importance of strategies for prevention, diagnosis and treatment in this population.
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    Síntese de peptídeos ricos em prolina e arginina e atividade inibitória sobre o complexo proteolítico proteassoma 20s de mamíferos e do parasito Schistosoma mansoni.
    (Programa de Pós-Graduação em Biotecnologia. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2012) Breguez, Gustavo Silveira; Andrade, Milton Hércules Guerra de
    O proteassoma tem sido considerado um potencial alvo farmacológico devido ao seu envolvimento em processos vitais relacionados à proteólise celular, sendo a mais importante entre as vias de degradação. Recentemente, foi demonstrado que moléculas análogas ao peptídeo PR-11(RRRPRPPYLPR), que corresponde aos 11 primeiros aminoácidos da porção N-terminal do peptídeo PR-39, apresentam uma forte inibição sobre o proteassoma humano 20S, inibindo a atividade quimotripsina-símile em concentrações namolares (nM). Os peptídeos dessa classe desempenham importantes atividades anti-inflamatórias e angiogênicas. Novas moléculas envolvendo substituições conservativas de aminoácidos e sínteses de peptídeos cíclicos podem ser derivadas dessas estruturas, com o intuito de se encontrar melhores inibidores. Dessa forma, este trabalho teve como objetivos a síntese do peptídeo PR-11 e análogos para a realização de ensaios de atividade peptidásica in vitro, visando verificar o potencial inibitório dos peptídeos sintetizados em frações enriquecidas com proteassoma 20S de fígado de camundongos Swiss, eritrócitos humanos e vermes adultos de Schistosoma mansoni. Os peptídeos foram sintetizados empregando-se a estratégia Fmoc em fase sólida, purificados em sistema HPLC e identificados por espectrometria de massas. As frações com proteassoma 20S foram obtidas a partir de cromatografias de filtração molecular em Sephacryl S-400, as quais permitiram preparar satisfatoriamente enriquecidos de proteassoma livres de proteases de baixa massa molecular. Todos os análogos foram capazes de inibir a atividade quimotripsina-símile in vitro do proteassoma 20S das três espécies estudadas, utilizando a concentração final de 1μM de peptídeo. De um modo geral, as intensidades das atividades inibitórias foram similares para o proteassoma 20S de camundongos e humanos e menores para o de vermes adultos de Schistosoma mansoni. Os análogos cíclicos C8C15 e C9C15, quando comparados ao PR-11, apresentaram menor atividade sobre o proteassoma de humanos e atividade similar quanto à inibição em Schistosoma mansoni. Tal fato sugere que esse tipo de alteração estrutural possa ser útil na busca por inibidores mais seletivos para o proteassoma 20S do parasito.