RESUMO
Ion channels are well placed to transduce environmental cues into signals used by cells to generate a wide range of responses, but little is known about their role in the regulation of RNA metabolism. Here we show that the TRPV4 cation channel binds the DEAD-box RNA helicase DDX3X and regulates its function. TRPV4-mediated Ca2+ influx releases DDX3X from the channel and drives DDX3X nuclear translocation, a process that involves calmodulin (CaM) and the CaM-dependent kinase II. Genetic depletion or pharmacological inhibition of TRPV4 diminishes DDX3X-dependent functions, including nuclear viral export and translation. Furthermore, TRPV4 mediates Ca2+ influx and nuclear accumulation of DDX3X in cells exposed to the Zika virus or the purified viral envelope protein. Consequently, targeting of TRPV4 reduces infectivity of dengue, hepatitis C and Zika viruses. Together, our results highlight the role of TRPV4 in the regulation of DDX3X-dependent control of RNA metabolism and viral infectivity.
Assuntos
Cálcio/metabolismo , RNA Helicases DEAD-box/metabolismo , Canais de Cátion TRPV/metabolismo , Transporte Ativo do Núcleo Celular , Sinalização do Cálcio , RNA Helicases DEAD-box/genética , Vírus da Dengue/genética , Vírus da Dengue/patogenicidade , Vírus da Dengue/fisiologia , Células HeLa , Hepacivirus/genética , Hepacivirus/patogenicidade , Hepacivirus/fisiologia , Humanos , Modelos Biológicos , Biossíntese de Proteínas , RNA Viral/genética , RNA Viral/metabolismo , Canais de Cátion TRPV/genética , Técnicas do Sistema de Duplo-Híbrido , Virulência/genética , Virulência/fisiologia , Replicação Viral/genética , Replicação Viral/fisiologia , Zika virus/genética , Zika virus/patogenicidade , Zika virus/fisiologiaAssuntos
Peptídeos e Proteínas de Sinalização Intracelular/genética , Linfoma de Células B/genética , Neoplasias do Mediastino/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Proteínas Repressoras/genética , Deleção de Genes , Homozigoto , Humanos , Linfoma de Células B/diagnóstico , Neoplasias do Mediastino/diagnóstico , Proteína 1 Supressora da Sinalização de Citocina , Proteínas Supressoras da Sinalização de CitocinaRESUMO
In B-cell chronic lymphocytic leukemia (B-CLL), somatic mutation of IgVH genes defines a subgroup with favorable prognosis, whereas the absence of IgVH mutations is correlated with a worse outcome. Mutations of the BCL-6 gene are also observed in a subset of B-CLL, but the clinical significance of this molecular alteration remains uncertain. We examined the distribution of IgVH and BCL-6 gene mutations in 95 well-characterized patients with Binet stage A B-CLL, and correlated them with clinical, laboratory, cytogenetic findings and disease progression. Mutations of the BCL-6 gene were observed only in cases harboring mutated IgVH. Unexpectedly, coexistence of IgVH and BCL-6 mutations was correlated with shorter treatment-free interval (TFI) compared to cases harboring only IgVH mutation (median, 55 months vs not reached; P=0.01), resembling the clinical course of unmutated IgVH cases (median TFI, 44 months). As expected, deletions of 17p13 (P53 locus) and 11q22 (ATM locus) were observed in cases with unmutated IgVH, except one patient who showed mutations of both IgVH and BCL-6. No other statistically significant differences were observed among the genetic subgroups. Our data indicate that BCL-6 mutations identify a subgroup of Binet stage A B-CLL patients with a high risk of progression despite the presence of mutated IgVH gene.
Assuntos
Proteínas de Ligação a DNA/genética , Leucemia Linfocítica Crônica de Células B/genética , Mutação , Proteínas Proto-Oncogênicas/genética , Fatores de Transcrição/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Deleção Cromossômica , Cromossomos Humanos Par 11 , Cromossomos Humanos Par 17 , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/diagnóstico , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Proteínas Proto-Oncogênicas c-bcl-6RESUMO
Patients with mantle cell lymphoma (MCL) may present with either nodal or leukemic disease. The molecular determinants underlying this different biologic behavior are not known. This study compared the pattern of genetic abnormalities in patients with nodal and leukemic phases of MCL using comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) for specific gene loci. Although both leukemic and nodal MCL showed similar genomic patterns of losses (involving 6q, 11q22-q23, 13q14, and 17p13) and gains (affecting 3q and 8q), genomic loss of chromosome 8p occurred more frequently in patients with leukemic disease (79% versus 11%, P <.001). Subsequent CGH analysis confirmed the genomic loss of 8p21-p23 in 6 of 8 MCL cell lines. Interestingly, MYC gene amplification was restricted to cases with 8p deletion. These data indicate the presence of a novel tumor suppressor gene locus on 8p, whose deletion may be associated with leukemic dissemination and poor prognosis in patients with MCL.
Assuntos
Cromossomos Humanos Par 8 , Deleção de Genes , Genes Supressores de Tumor , Linfoma de Célula do Manto/genética , Linfoma de Célula do Manto/patologia , Amplificação de Genes , Genes myc/genética , Humanos , Hibridização In Situ , Hibridização de Ácido Nucleico , PrognósticoRESUMO
Some confusion exists in the literature about which criteria should be used to define familial melanoma. This could explain the different reported frequencies of mutations in predisposing genes, mostly CDKN2A, in these patients. This study evaluated the human leucocyte antigen (HLA) class II genotype and the presence of mutations in CDKN2A and CDK4 genes in 2 families with very different clinical features. The family with a germinal mutation in exon 2 of CDKN2A (Gly101Try) presented the following clinical features: 3 first-degree affected members, 1 of whom had 2 melanomas, and all the melanomas appearing before 35 years of age. In contrast, the second family did not present any mutation in the studied genes and included 2 first-degree affected members diagnosed at over 45 years of age. Neither family showed an association with HLA genotype. Other genes are also involved in familial melanoma but, when the CDKN2A gene is affected, some clinical features seem to be uniform.
