RESUMEN
Adult T-cell leukemia (ATL) arises from a human T-cell leukemia virus type I (HTLV-I)-infected cell and has few therapeutic options. Here, we have uncovered a previously unrecognized role for a ubiquitin-editing enzyme A20 in the survival of HTLV-I-infected cells. Unlike in lymphomas of the B-cell lineage, A20 is abundantly expressed in primary ATL cells without notable mutations. Depletion of A20 in HTLV-I-infected cells resulted in caspase activation, cell death induction and impaired tumorigenicity in mouse xenograft models. Mechanistically, A20 stably interacts with caspase-8 and Fas-associated via death domain (FADD) in HTLV-I-infected cells. Mutational studies revealed that A20 supports the growth of HTLV-I-infected cells independent of its catalytic functions and that the zinc-finger domains are required for the interaction with and regulation of caspases. These results indicate a pivotal role for A20 in the survival of HTLV-I-infected cells and implicate A20 as a potential therapeutic target in ATL.
Asunto(s)
Caspasa 8/genética , Proteínas de Unión al ADN/genética , Proteína de Dominio de Muerte Asociada a Fas/genética , Virus Linfotrópico T Tipo 1 Humano/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Leucemia-Linfoma de Células T del Adulto/genética , Proteínas Nucleares/genética , Adulto , Animales , Caspasa 3/genética , Caspasa 3/metabolismo , Caspasa 7/genética , Caspasa 7/metabolismo , Caspasa 8/metabolismo , Muerte Celular , Línea Celular , Proteínas de Unión al ADN/antagonistas & inhibidores , Proteínas de Unión al ADN/metabolismo , Proteína de Dominio de Muerte Asociada a Fas/metabolismo , Femenino , Regulación Leucémica de la Expresión Génica , Vectores Genéticos , Células HEK293 , Interacciones Huésped-Patógeno , Virus Linfotrópico T Tipo 1 Humano/patogenicidad , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Lentivirus/genética , Leucemia-Linfoma de Células T del Adulto/metabolismo , Leucemia-Linfoma de Células T del Adulto/patología , Leucemia-Linfoma de Células T del Adulto/virología , Ratones , Ratones Endogámicos NOD , Trasplante de Neoplasias , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Carga Tumoral , Proteína 3 Inducida por el Factor de Necrosis Tumoral alfaAsunto(s)
Síndrome de Creutzfeldt-Jakob/genética , Síndrome de Creutzfeldt-Jakob/patología , Mutación , Polimorfismo Genético/genética , Encéfalo/patología , Codón/genética , Síndrome de Creutzfeldt-Jakob/diagnóstico , Resultado Fatal , Predisposición Genética a la Enfermedad , Humanos , Microesferas , Persona de Mediana Edad , Mutación/genéticaRESUMEN
Congenital hypofibrinogenemia, fibrinogen Tottori II, caused by a nonsense mutation in the fibrinogen Bbeta chain gene, was found in a 68-year-old Japanese female. The plasma fibrinogen level was 99.2 mg dL(-1) as determined by the thrombin time method. No overt molecular abnormalities were observed in purified patient fibrinogen by SDS-PAGE analysis. After sequencing all exons and exon-intron boundaries of three fibrinogen genes, we found a heterozygous single point mutation of T-->G at position 3356 of the patient fibrinogen Bbeta chain gene. This nucleotide mutation results in a nonsense mutation (TAT sequence for Bbeta 41Tyr to TAG sequence for a translation termination signal). The mutation was confirmed by polymerase chain reaction-restriction fragment length polymorphism analysis, since this nucleotide mutation results in a new NheI recognition sequence at this position. These data indicated that the nonsense mutation of the fibrinogen Bbeta chain gene caused a truncated fibrinogen Bbeta chain, which may not be assembled in the fibrinogen molecule.
Asunto(s)
Trastornos de las Proteínas de Coagulación/genética , Codón sin Sentido , Fibrinógenos Anormales/genética , Anciano , Trastornos de las Proteínas de Coagulación/congénito , Análisis Mutacional de ADN/métodos , Desoxirribonucleasas de Localización Especificada Tipo II , Femenino , Fibrinógeno/análisis , Fibrinógeno/genética , Humanos , Mutación PuntualRESUMEN
In this study, we demonstrate that an Epstein-Barr virus-transformed B cell line, A-11, produced interleukin-1 (IL-1), a cytokine that regulates bone remodeling. A-11 cells produce IL-1 in a cell dose- and culture time-related manner. The IL-1 activity was neutralized by recombinant human IL-1 (rhIL-1) alpha antiserum, but not by rhIL-1 beta antiserum. The IL-1 was semi-purified by (NH4)2SO4 precipitation, Superose prep 12 gel filtration, and anion-exchange chromatography strongly stimulated in vitro bone resorption. The stimulatory effect of the purified IL-1 on bone resorption was prostaglandin independent. Purified IL-1 inhibited DNA and collagen synthesis in the osteoblastic cell line MC3T3-E1. However, it enhanced significantly the cellular activity of alkaline phosphatase (EC 3.1.3.1), a marker enzyme for differentiation of osteoblasts. On the other hand, A-11 cell proliferation was inhibited by addition of rhIL-1 alpha antiserum, but not by rhIL-1 beta antiserum. And cell proliferation was stimulated by exogenous rhIL-1 alpha and -beta.
Asunto(s)
Linfocitos B/metabolismo , Resorción Ósea , Transformación Celular Viral , Herpesvirus Humano 4 , Interleucina-1/biosíntesis , Fosfatasa Alcalina/metabolismo , Sulfato de Amonio , División Celular , Línea Celular Transformada , Precipitación Química , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Colágeno/biosíntesis , ADN/biosíntesis , Humanos , Sueros Inmunes/farmacología , Interleucina-1/aislamiento & purificación , Interleucina-1/farmacología , Osteoblastos/metabolismo , Proteínas RecombinantesRESUMEN
Steady flows and pulsatile flows of a Newtonian fluid through a channel with a rectangular hump were numerically studied as a two-dimensional model of blood flow in a constricted artery. From the numerical calculation, it was shown that one of the hydrodynamic causes of endothelial lesion of artery and post-stenotic dilatation can be found in the large temporal variation of shear stress behind a constricted portion of artery. Local maximum of the pressure there can be seen as secondary factor for the post-stenotic dilatation.