RESUMO
BACKGROUND: A large outbreak of diarrhea and the hemolytic-uremic syndrome caused by an unusual serotype of Shiga-toxin-producing Escherichia coli (O104:H4) began in Germany in May 2011. As of July 22, a large number of cases of diarrhea caused by Shiga-toxin-producing E. coli have been reported--3167 without the hemolytic-uremic syndrome (16 deaths) and 908 with the hemolytic-uremic syndrome (34 deaths)--indicating that this strain is notably more virulent than most of the Shiga-toxin-producing E. coli strains. Preliminary genetic characterization of the outbreak strain suggested that, unlike most of these strains, it should be classified within the enteroaggregative pathotype of E. coli. METHODS: We used third-generation, single-molecule, real-time DNA sequencing to determine the complete genome sequence of the German outbreak strain, as well as the genome sequences of seven diarrhea-associated enteroaggregative E. coli serotype O104:H4 strains from Africa and four enteroaggregative E. coli reference strains belonging to other serotypes. Genomewide comparisons were performed with the use of these enteroaggregative E. coli genomes, as well as those of 40 previously sequenced E. coli isolates. RESULTS: The enteroaggregative E. coli O104:H4 strains are closely related and form a distinct clade among E. coli and enteroaggregative E. coli strains. However, the genome of the German outbreak strain can be distinguished from those of other O104:H4 strains because it contains a prophage encoding Shiga toxin 2 and a distinct set of additional virulence and antibiotic-resistance factors. CONCLUSIONS: Our findings suggest that horizontal genetic exchange allowed for the emergence of the highly virulent Shiga-toxin-producing enteroaggregative E. coli O104:H4 strain that caused the German outbreak. More broadly, these findings highlight the way in which the plasticity of bacterial genomes facilitates the emergence of new pathogens.
Assuntos
Surtos de Doenças , Infecções por Escherichia coli/microbiologia , Genoma Bacteriano , Síndrome Hemolítico-Urêmica/microbiologia , Escherichia coli Shiga Toxigênica/genética , Técnicas de Tipagem Bacteriana , Sequência de Bases , Diarreia/epidemiologia , Diarreia/microbiologia , Infecções por Escherichia coli/epidemiologia , Fezes/microbiologia , Feminino , Alemanha/epidemiologia , Síndrome Hemolítico-Urêmica/epidemiologia , Humanos , Pessoa de Meia-Idade , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Escherichia coli Shiga Toxigênica/classificação , Escherichia coli Shiga Toxigênica/isolamento & purificaçãoRESUMO
The aim of this study was to investigate the changes induced by high tidal volume ventilation (HVTV) in pulmonary expression of micro-RNAs (miRNAs) and identify potential target genes and corresponding miRNA-gene networks. Using a real-time RT-PCR-based array in RNA samples from lungs of mice subjected to HVTV for 1 or 4 h and control mice, we identified 65 miRNAs whose expression changed more than twofold upon HVTV. An inflammatory and a TGF-ß-signaling miRNA-gene network were identified by in silico pathway analysis being at highest statistical significance (P = 10(-43) and P = 10(-28), respectively). In the inflammatory network, IL-6 and SOCS-1, regulated by miRNAs let-7 and miR-155, respectively, appeared as central nodes. In TGF-ß-signaling network, SMAD-4, regulated by miR-146, appeared as a central node. The contribution of miRNAs to the development of lung injury was evaluated in mice subjected to HVTV treated with a precursor or antagonist of miR-21, a miRNA highly upregulated by HVTV. Lung compliance was preserved only in mice treated with anti-miR-21 but not in mice treated with pre-miR-21 or negative-control miRNA. Both alveolar-arterial oxygen difference and protein levels in bronchoalveolar lavage were lower in mice treated with anti-miR-21 than in mice treated with pre-miR-21 or negative-control miRNA (D(A-a): 66 ± 27 vs. 131 ± 22, 144 ± 10 mmHg, respectively, P < 0.001; protein concentration: 1.1 ± 0.2 vs. 2.3 ± 1, 2.1 ± 0.4 mg/ml, respectively, P < 0.01). Our results show that HVTV induces changes in miRNA expression in mouse lungs. Modulation of miRNA expression can affect the development of HVTV-induced lung injury.
Assuntos
Biomarcadores/metabolismo , Perfilação da Expressão Gênica , MicroRNAs/genética , Lesão Pulmonar Induzida por Ventilação Mecânica/etiologia , Lesão Pulmonar Induzida por Ventilação Mecânica/patologia , Animais , Líquido da Lavagem Broncoalveolar , Modelos Animais de Doenças , Redes Reguladoras de Genes , Hibridização In Situ , Pulmão/citologia , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Fator de Crescimento Transformador beta/farmacologiaRESUMO
The observed cooperation on the level of genes, cells, tissues, and individuals has been the object of intense study by evolutionary biologists, mainly because cooperation often flourishes in biological systems in apparent contradiction to the selfish goal of survival inherent in Darwinian evolution. In order to resolve this paradox, evolutionary game theory has focused on the Prisoner's Dilemma (PD), which incorporates the essence of this conflict. Here, we encode strategies for the iterated Prisoner's Dilemma (IPD) in terms of conditional probabilities that represent the response of decision pathways given previous plays. We find that if these stochastic strategies are encoded as genes that undergo Darwinian evolution, the environmental conditions that the strategies are adapting to determine the fixed point of the evolutionary trajectory, which could be either cooperation or defection. A transition between cooperative and defective attractors occurs as a function of different parameters such as mutation rate, replacement rate, and memory, all of which affect a player's ability to predict an opponent's behavior. These results imply that in populations of players that can use previous decisions to plan future ones, cooperation depends critically on whether the players can rely on facing the same strategies that they have adapted to. Defection, on the other hand, is the optimal adaptive response in environments that change so quickly that the information gathered from previous plays cannot usefully be integrated for a response.
Assuntos
Fenômenos Fisiológicos Celulares , Biologia Computacional/métodos , Teoria dos Jogos , Genética Populacional , Modelos Genéticos , Fenômenos Fisiológicos Celulares/genética , Fenômenos Fisiológicos Celulares/fisiologia , Simulação por Computador , Genes , Mutação , Análise de Componente Principal , Processos EstocásticosRESUMO
Familial Mediterranean fever (FMF) is an autosomal, recessive disease, attributed to mutations in MEFV gene encoding pyrin, which is characterized by recurrent, acute and self-limiting attacks of fever as well as an increased neutrophil and monocyte apoptosis. Most disease-associated mutations in MEFV gene reside on the C-terminal PRYSPRY (B30.2) domain of pyrin, an area found to interact with the pro-apoptotic protein Siva. Because apoptotic events may be contributing to endogenous inflammation we hypothesized that mutations in pyrin may affect Siva-mediated apoptosis. The confirmation of this hypothesis would be of a great biological significance since it would be demonstrated a connection between apoptosis and inflammation. We used homology modeling to construct a 3-D model of Siva protein and the constructed model of Siva defined structural elements with potential of binding other proteins to induce apoptosis. Given that Siva protein binds pyrin as shown by transfection and immunoprecipitation experiments, apoptosis was assessed by FACS and Western blotting. No differences in rates of apoptosis in myeloid cells (THP-1) upon transfection with either wt pyrin or mutant forms of pyrin were found. Patients with FMF did not display any mutations in the Siva-1 (full length) gene. Siva-1 was not linked to pyrin in the major predicted FMF gene network constructed using a literature-curated gene signature for FMF. These results suggest that Siva-mediated unprovoked apoptosis is not likely to be involved in the pathogenesis of FMF.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Febre Familiar do Mediterrâneo/metabolismo , Sequência de Aminoácidos , Apoptose , Proteínas Reguladoras de Apoptose/química , Proteínas Reguladoras de Apoptose/genética , Linhagem Celular Tumoral , Proteínas do Citoesqueleto/metabolismo , Febre Familiar do Mediterrâneo/genética , Febre Familiar do Mediterrâneo/patologia , Redes Reguladoras de Genes , Humanos , Dados de Sequência Molecular , Mutação , Conformação Proteica , Estrutura Terciária de Proteína , PirinaRESUMO
Arterial hypertension (HT) is one of the most frequently recorded comorbidities among patients under antiangiogenic therapy. Inhibitors of vascular endothelial growth factor and vascular endothelial growth factor receptors are most commonly involved in new onset or exacerbation of pre-existing controlled HT. From the pathophysiology point of view, data support that reduced nitric oxide release and sodium and fluid retention, microvascular rarefaction, elevated vasoconstrictor levels, and globular injury might contribute to HT. The purpose of this review was to present recent evidence regarding the incidence of HT induced by antiangiogenic agents, to analyze the pathophysiological mechanisms, and to summarize current recommendations for the management of elevated blood pressure in this field.
Assuntos
Inibidores da Angiogênese/efeitos adversos , Pressão Arterial/efeitos dos fármacos , Hipertensão/induzido quimicamente , Inibidores de Proteínas Quinases/efeitos adversos , Animais , Anti-Hipertensivos/administração & dosagem , Humanos , Hipertensão/epidemiologia , Hipertensão/fisiopatologia , Fatores de Risco , Comportamento de Redução do Risco , Resultado do TratamentoRESUMO
OBJECTIVES: We investigated in vivo in aortic valve stenosis (AVS) whether there is: 1) thermal heterogeneity within the valve leaflets; 2) temperature difference between the leaflets and the ascending aortic wall; and 3) a possible correlation between heat production, inflammation, and neoangiogenesis. BACKGROUND: Histological studies have demonstrated a potential role of inflammation and neoangiogenesis in AVS. METHODS: We examined 96 leaflets scheduled for aortic valve replacement. Twenty-five patients had AVS, and 7 had aortic valve insufficiency (AVI). Temperature measurements were performed right before hypothermic cardioplegia. Temperature difference (DeltaT) was assigned as the mean temperature of each leaflet minus the temperature of the aortic wall. Histological, immunohistological analysis, and vascular endothelial growth factor (VEGF) immunoreactivity was performed. RESULTS: Significant thermal heterogeneity was recorded within the leaflets of AVS, compared with AVI (1.52 +/- 1.35 degrees C vs. 0.13 +/- 0.11 degrees C, p < 0.01). In AVS DeltaT was greater in all leaflets compared with the AVI group (p < 0.01). Leaflets of AVS had increased inflammatory cell infiltration, calcium deposit, and anti-VEGF expression compared with AVI (p < 0.01). CONCLUSIONS: Thermal heterogeneity is increased in AVS and correlates with inflammatory mononuclear cell infiltration, expression of pro-inflammatory cytokines and neoangiogenic factors.