RESUMEN
Hyperbaric oxygen (HBO) is 100% oxygen administered at elevated atmospheric pressure. In this study, we examined the effect of HBO on hematopoietic cell apoptosis. Cells exposed to HBO were incubated in a chamber containing 97.9% O(2) and 2.1% CO(2) at 2.4 atmospheres absolute (ATA). HBO enhanced spontaneous HL-60 cell apoptosis in a time-dependent manner; a 12 h exposure increased apoptosis by 42%. Exposing these cells to hyperoxia at standard atmospheric pressure (95% O(2), 5% CO(2) at 1 ATA) or increased pressure alone (8.75% O(2), 2.1% CO(2) at 2.4 ATA) had minimal effect on apoptosis. HBO also enhanced stimulus-induced apoptosis. HL-60 cells stimulated to die using gamma radiation underwent 33% more apoptosis than cells exposed to radiation alone. HBO enhanced melphalan, camptothecin, and chlorambucil-induced apoptosis by 22%, 13%, and 8%, respectively. Jurkat cells stimulated to die with anti-Fas antibody underwent 44% more apoptosis when exposed to HBO. Spontaneous apoptosis was increased by 15% in HBO-exposed murine thymocytes. HBO's effect on apoptosis did not require new protein synthesis. As expected, HBO exposure increased the intracellular concentration of H(2)O(2). Incubating HL-60 cells in the presence of dehydroascorbic acid partially abrogated HBO-induced increases in intracellular H(2)O(2) and apoptosis. In summary, HBO enhances spontaneous and stimulus-induced apoptosis in hematopoietic cells, at least in part, by enhancing the intracellular accumulation of H(2)O(2).
Asunto(s)
Apoptosis/efectos de los fármacos , Sistema Hematopoyético/citología , Sistema Hematopoyético/efectos de los fármacos , Oxigenoterapia Hiperbárica , Animales , Apoptosis/fisiología , Caspasa 3 , Caspasas/biosíntesis , Catalasa/metabolismo , Ácido Deshidroascórbico/farmacología , Femenino , Células HL-60 , Humanos , Peróxido de Hidrógeno/metabolismo , Presión Hidrostática , Hiperoxia , Técnicas In Vitro , Células Jurkat , Ratones , Ratones Endogámicos BALB C , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Oxígeno/fisiología , Inhibidores de la Síntesis de la Proteína/farmacología , Especies Reactivas de Oxígeno/metabolismo , Linfocitos T/citología , Linfocitos T/efectos de los fármacosRESUMEN
Pseudorabies rabies (PrV) replication in Vero cells was suppressed by treatment with human natural interferon-alpha (IFN-alpha). Messenger RNA transcribed from the PrV immediate-early (IE) gene was reduced in the IFN-alpha-treated cells. Transient expression assays showed that transcription from the PrV IE promoter was selectively inhibited in the IFN-alpha-treated cells. Analysis of deletion mutants of the PrV IE promoter sequence suggested that at least one element between the transcription initiation site (+1) and -90 in the PrV IE promoter was concerned with the negative regulation.
Asunto(s)
Regulación Viral de la Expresión Génica/efectos de los fármacos , Genes Inmediatos-Precoces/efectos de los fármacos , Herpesvirus Suido 1/fisiología , Interferón-alfa/farmacología , Replicación Viral/efectos de los fármacos , Animales , Línea Celular , Cloranfenicol O-Acetiltransferasa/biosíntesis , Chlorocebus aethiops , Herpesvirus Suido 1/efectos de los fármacos , Herpesvirus Suido 1/genética , Humanos , Cinética , Regiones Promotoras Genéticas , ARN Mensajero/biosíntesis , Proteínas Recombinantes/biosíntesis , Porcinos , Transcripción Genética/efectos de los fármacos , Transfección , Células VeroRESUMEN
A chimeric gene encoding a fusion protein consisting of the DNA-binding domain of the immediate-early (IE) protein of pseudorabies virus (PRV) and a tail-truncated Vmw65 of herpes simplex virus 1, lacking the transcription activation domain, was constructed. The chimeric gene product inhibited transcription from the PRV IE promoter in a transient expression assay. A HeLa cell line stably transformed with the chimeric gene showed remarkable resistance to PRV infection. In the transformed cells infected with PRV, transcription of the PRV IE gene was repressed, indicating that the resistance of the cells to PRV infection was due to interference with IE gene transcription by the fusion protein.