Navegando por Palavras-chave "Exosomes"

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    Análise de microRNAs exossomais como potenciais biomarcadores precoces da Lesão Renal Aguda induzida por lipopolissacarídeo em ratos
    (Universidade Federal de São Paulo (UNIFESP), 2019-09-26) Silva, Carolina Carvalho Serres Da [UNIFESP]; Boim, Mirian Aparecida [UNIFESP]; http://lattes.cnpq.br/8916858915652849; http://lattes.cnpq.br/9510389234856610; Universidade Federal de São Paulo (UNIFESP)
    Acute kidney injury (AKI) consists of the abrupt reduction of the glomerular filtration rate evidenced by increased serum creatinine and/or reduced urine output, compromising the electrolyte balance and the clearance of nitrogenous slags. The cause is multifactorial, and sepsis contributes to the high prevalence of AKI. It is known that the development and the delay in the identification of AKI is a risk factor for chronicity. In this way, its early detection is essential for trigger proper treatment strategies at a more opportune moment. Serum creatinine is not an optimal marker of renal dysfunction, since the elevation is detected late during AKI onset. microRNAs (miRs), a class of non-coding RNAs responsible for gene regulation, may be promising tools for the early detection of AKI. This class of molecules can be found in biological fluids within vesicles such as exosomes and microvesicles. Aim: To evaluate potential miRs that can be used as early biomarkers in sepsis-induced AKI. Methods: Male Wistar rats at 12 weeks of age undergoing intraperitoneal administration of lipopolysaccharides (LPS) at a dose of 7.5 mg/kg were used. Renal function was initially assessed by serum creatinine, with change detected 4 hr after LPS administration. In order to evaluate whether miRs could act as earlier biomarkers, blood samples were collected before and 2 hr after LPS infusion, and therefore before creatinine elevation. Exosomes in the serum were isolated and the total miRs were extracted for evaluation of the gene expression profile by the array PCR technique. Results: miR-181a-5p and miR-23b-3p showed higher expression in LPS-treated rats compared to the control animals (p<0.05). Bioinformatic studies showed that both miRs target molecules associated with carcinogenesis and to transcription factors that regulate genes related to proinflammatory cytokines. Conclusion: Considering that LPS activates transcription factors, leading to the production of proinflammatory cytokines, possible premature changes in serum levels of miR-181a-5p and miR-23b-3p may be able define earlier the sepsis-induced AKI.
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    Exosomes from patients with septic shock convey miRNAs related to inflammation and cell cycle regulation: new signaling pathways in sepsis?
    (Biomed Central Ltd, 2018) Real, Juliana Monte; Ferreira, Ludmila Rodrigues Pinto; Esteves, Gustavo Henrique; Koyama, Fernanda Christtanini; Dias, Marcos Vinicius Salles; Bezerra-Neto, Joao Evangelista; Cunha-Neto, Edecio; Machado, Flavia Ribeiro [UNIFESP]; Salomão, Reinaldo [UNIFESP]; Azevedo, Luciano Cesar Pontes
    Background: Exosomes isolated from plasma of patients with sepsis may induce vascular apoptosis and myocardial dysfunction by mechanisms related to inflammation and oxidative stress. Despite previous studies demonstrating that these vesicles contain genetic material related to cellular communication, their molecular cargo during sepsis is relatively unknown. In this study, we evaluated the presence of microRNAs (miRNAs) and messenger RNAs (mRNAs) related to inflammatory response and redox metabolism in exosomes of patients with septic shock. Methods: Blood samples were collected from 24 patients with septic shock at ICU admission and after 7 days of treatment. Twelve healthy volunteers were used as control subjects. Exosomes were isolated by ultracentrifugation, and their miRNA and mRNA content was evaluated by qRT-PCR array. Results: As compared with healthy volunteers, exosomes from patients with sepsis had significant changes in 65 exosomal miRNAs. Twenty-eight miRNAs were differentially expressed, both at enrollment and after 7 days, with similar kinetics (18 miRNAs upregulated and 10 downregulated). At enrollment, 35 differentially expressed miRNAs clustered patients with sepsis according to survival. The pathways enriched by the miRNAs of patients with sepsis compared with control subjects were related mostly to inflammatory response. The comparison of miRNAs from patients with sepsis according to hospital survival demonstrated pathways related mostly to cell cycle regulation. At enrollment, sepsis was associated with significant increases in the expression of mRNAs related to redox metabolism (myeloperoxidase, 64-fold
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    Perfil redox sazonal e o papel do fluido folicular na maturação de oócitos bovinos submetidos ao choque térmico
    (Universidade Federal de São Paulo, 2017-09-27) Rodrigues, Thais Alves [UNIFESP]; Lopes, Fabiola Freitas de Paula [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Heat stress promotes changes in reproductive microenvironment, compromising the oocyte and embryos development. High temperature alters cells redox balance. However, it is not know how the temperature affects the oocyte microenvironment as wells as the role of follicular fluid (FF) in heat-shocked oocytes. The aim of the first experiment was to determine the effect of seasonal heat stress in the activity of antioxidant enzymes, lipid peroxidation and total protein in bovine FF. Glutathione peroxidase activity was reduced in FF collected in summer compared to winter. However, there was no effect on superoxide dismutase and lipid peroxidation. There was a tendency of total protein reduction in FF in summer. In the second series of experiments, the heat stress was applied in vitro (heat shock). The aim of those experiments was to determine the role of FF in cumulus cells (CCs) expansion, nuclear maturation, protein quinase activated by mitogens (MAPK) activity, oxygen reactive species (ROS) production and developmental competence of bovine oocytes subjected to heat shock during in vitro maturation (IVM). Cumulus-oocyte complexes (COCs) were collected from slaughterhouse ovaries and distributed to the treatments heat shock (41ºC for 14 h followed by 38.5°C for 8 h) or control (38.5ºC for 22 h) in the presence of 0, 10 or 15% FF. For CCs expansion evaluation, images before and after COCs IVM were acquired. The oocytes were stained with 5 μg/ml Hoechst 33342 to evaluate nuclear maturation. Heat shock reduced CCs expansion and nuclear maturation. However, supplementation of IVM medium with 10% FF reverted these deleterious effects. MAPK activity was determined by Western Blotting. There was no effect of heat shock or FF in oocyte MAPK activity. However, heat shock enhanced MAPK activity in CCs and 10% FF was capable of reverting this effect. Heat shock also reduced the number of cleaved oocytes and the percentage of blastocyst. However, addition of 10% FF reverted this effect. The third series of experiments determined the role of FF exosomes in CCs expansion and embryos development competence in oocytes subjected to heat shock during IVM. Exosomes were isolated by ultracentrifugation. Heat shock reduced the expansion of CCs, cleavage and blastocyst rates. However, supplementation with FF exosomes (16 x 109 particles/ml) reverted this effect. Heat shock did not affect gene expression in blastocysts. In addition, exosomes reduced expression of NANOG and enhanced the expression of SOX2, indicating that exosome supplementation accelerated the embryo development. Exosomes were uptaken by CCs and not by the oocyte, indicating that the thermoprotective effect of FF can be mediated by exosomes via CCs. In conclusion, the moderate increase in environmental temperature is capable of changing the antioxidant system in follicular fluid. In addition, exposure of oocytes to heat shock during IVM showed a negative impact in CCs expansion, nuclear maturation, MAPK activity and embryo development. However, both FF and exosomes were capable of reverting the heat stress deleterious effects.
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    Prnp/prion protein regulates the secretion of exosomes modulating cav1/caveolin-1-suppressed autophagy
    (Univ Federal Juiz Fora, Campus Univ, 2016) Dias, Marcos V. S.; Teixeira, Bianca L.; Rodrigues, Bruna R.; Sinigaglia-Coimbra, Rita [UNIFESP]; Porto-Carreiro, Isabel; Roffe, Martin; Hajj, Glaucia N. M.; Martins, Vilma R.
    Prion protein modulates many cellular functions including the secretion of trophic factors by astrocytes. Some of these factors are found in exosomes, which are formed within multivesicular bodies (MVBs) and secreted into the extracellular space to modulate cell-cell communication. The mechanisms underlying exosome biogenesis were not completely deciphered. Here, we demonstrate that primary cultures of astrocytes and fibroblasts from prnp-null mice secreted lower levels of exosomes than wild-type cells. Furthermore, prnp-null astrocytes exhibited reduced MVB formation and increased autophagosome formation. The reconstitution of PRNP expression at the cell membrane restored exosome secretion in PRNP-deficient astrocytes, whereas macroautophagy/autophagy inhibition via BECN1 depletion reestablished exosome release in these cells. Moreover, the PRNP octapeptide repeat domain was necessary to promote exosome secretion and to impair the formation of the CAV1-dependent ATG12-ATG5 cytoplasmic complex that drives autophagosome formation. Accordingly, higher levels of CAV1 were found in lipid raft domains instead of in the cytoplasm in prnp-null cells. Collectively, these findings demonstrate that PRNP supports CAV1-suppressed autophagy to protect MVBs from sequestration into phagophores, thus facilitating exosome secretion.
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    Revisão bibliográfica sobre Linfócitos B e as Vesículas Extracelulares liberadas por essas células
    (Universidade Federal de São Paulo, 2023-12-01) Oliveira, Julia Soares [UNIFESP]; Batista, Patricia Xander [UNIFESP]; http://lattes.cnpq.br/3620553457348403
    O sistema imunológico atua na proteção e homeostasia do organismo. Linfócitos B são células especializadas na produção de anticorpos, apresentação de antígenos, produção de citocinas e geração de células de memória. Essas células podem ser classificadas em linfócitos B-1 e B-2, cada um contribuindo de maneira única para a resposta imunológica. Células B-1 são conhecidos por sua participação na produção de anticorpos naturais, apresentando características como baixa afinidade e polirreatividade. Em contraste, os linfócitos B-2 desempenham um papel essencial na resposta adaptativa, produzindo anticorpos específicos em resposta a antígenos específicos. Além do seu papel na produção de anticorpos, os linfócitos B também estão envolvidos na geração de vesículas extracelulares (EVs). Essas pequenas vesículas liberadas pelos linfócitos podem transportar moléculas bioativas, incluindo proteínas e material genético, desempenhando papel crucial na comunicação intercelular. EVs podem modular a resposta imunológica, influenciando a ativação de outras células do sistema imunológico e desempenhando papel importante na regulação da inflamação. As EVs originadas de linfócitos B têm despertado crescente notoriedade na literatura devido ao seu potencial impacto em processos fisiológicos e patológicos
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    Vesículas extracelulares e sistema imunológico
    (Universidade Federal de São Paulo, 2020-10-02) Geraldo, Mariana Marques [UNIFESP]; Xander, Patricia [UNIFESP]; http://lattes.cnpq.br/3620553457348403; http://lattes.cnpq.br/9246970737548904
    Vesículas extracelulares são nanopartículas secretadas por quase todas as células presente em diferentes organismos (incluindo bactérias, fungos, protozoários, helmintos e células de mamíferos) e têm importante papel como mediadores na comunicação célula-célula e patógeno hospedeiro. As vesículas incluem os exossomos, microvesículas e corpos apoptóticos, diferenciadas pelo tamanho e composição e biogênese. Estudos mostraram a capacidade de vesículas extracelulares em armazenar e liberar moléculas como lipídios, proteínas e ácidos nucleicos e suas funções únicas relacionadas as células de origem como macrófagos e linfócitos. Trabalhos recentes mostraram que essas estruturas participam de diversos processos biológicos, da resposta imunológica, assim como no desenvolvimento de infecções e da progressão e patogênese de doenças infecciosas. Essas vesículas têm sido utilizadas para detecção, diagnostico e prognóstico de diversas doenças. A proposta deste trabalho foi realizar revisão bibliográfica sobre a estrutura das vesículas extracelulares, sua importância, sua ação no sistema imunológico e como podem ser utilizadas para diagnóstico de doenças negligenciadas, como a leishmaniose.