RESUMEN
Three strains of Pseudomonas aeruginosa were isolated: wild-type (WT, NO4) showed normal quorum sensing (QS), whereas QSD3 and QSD7 were QS-deficient (QSD) containing limited N-butyryl homoserine lactone (C4-HSL). The autoinducer activity produced by NO4 was found to be at least 50-fold higher than those by the QSD3 and the QSD7 strains. The QSDs produced lower levels of phenazine compounds (pyocyanin), siderophores (pyoverdine) and biosurfactants (rhamnolipids) than NO4. Therefore, the swarming motility and the swimming motility of the QSD3 and the QSD7 strains also decreased. Treatment with exogenous C4-HSL completely restored rhamnolipid production in both QSDs, suggesting that the biosynthesis of C4-HSL is defective. However, the biofilm production of the QSDs reached much higher levels than those of wild-types (NO4 and P. aeruginosa PAO1). And both QSD strains were more resistant than wild-type cell (NO4) against kanamycin and tobramycin. The RpoS gene, which function is related with QS, is point-nonsense mutated in QSD3 strain. But eleven QS-related genes in QSD3 were not mutated, compared to those of PAO1, which carries intact QS genes and is used as a positive control. This study is helpful in the development of novel approaches in the treatment of P. aeruginosa infections.
Asunto(s)
Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Percepción de Quorum/genética , Percepción de Quorum/fisiología , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/fisiología , Biopelículas/crecimiento & desarrollo , ADN Bacteriano/genética , Farmacorresistencia Bacteriana Múltiple , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos/genética , Glucolípidos/metabolismo , Kanamicina/farmacología , Oligopéptidos/metabolismo , Infecciones por Pseudomonas , Pseudomonas aeruginosa/efectos de los fármacos , Piocianina/metabolismo , Análisis de Secuencia , Análisis de Secuencia de ADN , Factor sigma/genética , Factor sigma/fisiología , Tobramicina/farmacología , Factores de Virulencia/genéticaRESUMEN
Amyloid ß peptide (Aß) induces hydrogen peroxide (H2O2) and superoxide generation, leading to neuronal death. Many studies have shown the involvement of NADPH oxidase, but the isotype-specific role was not assessed. Moreover, the activation status of phosphoinositide 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) 1/2 is unclear in extracellular H2O2 generation. In this paper, we showed that Aß1-42 induced extracellular H2O2 generation and the resulting cytotoxicity in a concentration-dependent manner. Nox2- and Nox4-specific siRNAs suppressed H2O2 and superoxide generation. LY294002 and U0126, inhibitors of PI3K and ERK1/2, respectively, reduced H2O2 generation in concentration-dependent manners. Furthermore, PI3K activation is responsible for ERK1/2 phosphorylation. An additional increase in H2O2 generation and corresponding cytotoxicity was observed after treatment with Aß1-42 and glutamate. These results suggest that Aß1-42 enhances the neuronal vulnerability to oxidative injury in Alzheimer's disease (AD) by increasing H2O2 generation.
Asunto(s)
Péptidos beta-Amiloides/metabolismo , Peróxido de Hidrógeno/metabolismo , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Neuronas/metabolismo , Fragmentos de Péptidos/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Péptidos beta-Amiloides/toxicidad , Animales , Dominio Catalítico/genética , Células Cultivadas , Activación Enzimática , Espacio Extracelular/metabolismo , Técnicas de Inactivación de Genes , Ácido Glutámico/metabolismo , Ácido Glutámico/toxicidad , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Ratones , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , NADPH Oxidasa 2 , NADPH Oxidasa 4 , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , Neuronas/efectos de los fármacos , Fragmentos de Péptidos/toxicidad , Inhibidores de las Quinasa Fosfoinosítidos-3 , Cultivo Primario de Células , Superóxidos/metabolismoRESUMEN
BACKGROUND: Lung cancer is the leading cause of cancer deaths worldwide. We evaluated the diagnostic potential of sera XAGE-1a and XAGE-1d in lung cancer, both of which are variants of the X antigen family, member 1. METHODS: The expression levels of XAGE-1a and XAGE-1d in cell lines were determined using western blot analysis. Competitive ELISA was used to analyze XAGE-1a and XAGE-1d levels in culture supernatants and sera from 194 lung cancer patients and 194 healthy sex- and age-group-matched controls. To evaluate the diagnostic performance of these proteins, we also analyzed carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA 21-1) in culture supernatants and 388 sera using commercial ELISA kits. RESULTS: XAGE-1a and XAGE-1d proteins were expressed in both breast cancer and lung cancer cell lines, but they were only secreted by the latter. The areas under the curves (AUCs) for XAGE-1a and XAGE-1d were 0.787 and 0.806, respectively. The cutoff values (sensitivity, specificity) for XAGE-1a and XAGE-1d were 1.62 ng/ml (0.866, 0.572) and 2.51 ng/ml (0.871, 0.613), respectively. The diagnostic performance was improved for patients with squamous cell carcinoma. The AUC values for XAGE-1a and XAGE-1d for patients with squamous cell carcinoma versus a group containing all healthy participants and patients with any illness other than squamous cell carcinoma were similar to those for CEA and CYFRA 21-1. Better performance (AUC: 0.914) for all patients was obtained when using a combination of four markers (Random Forest). CONCLUSIONS: Sera XAGE-1a and XAGE-1d are potential biomarkers for lung cancer; they display a diagnostic performance comparable to that of CEA or CYFRA 21-1. Further studies are needed to evaluate the diagnostic and prognostic potential of XAGE-1a and XAGE-1d in lung cancer.