RESUMO
A healthy, 34-year-old primigravida at 41 weeks gestational age presented for cesarean delivery due to a category 2 fetal heart tracing remote from delivery. After completion of the surgery under epidural anesthesia, bilateral quadratus lumborum blocks were performed for postoperative pain. Approximately 4 hours later, the patient developed left-sided arm weakness, left miosis, and ptosis. These symptoms resolved within 24 hours. Considering the time course of her symptoms, we believe that the quadratus lumborum block was the likely culprit.
Assuntos
Síndrome de Horner/induzido quimicamente , Bloqueio Nervoso/efeitos adversos , Dor Pós-Operatória/terapia , Adulto , Cesárea/efeitos adversos , Feminino , Humanos , GravidezRESUMO
Epigenetic gene silencing by histone modifications and DNA methylation is essential for cancer development. The molecular mechanism that promotes selective epigenetic changes during tumorigenesis is not understood. We report here that the PIAS1 SUMO ligase is involved in the progression of breast tumorigenesis. Elevated PIAS1 expression was observed in breast tumor samples. PIAS1 knockdown in breast cancer cells reduced the subpopulation of tumor-initiating cells, and inhibited breast tumor growth in vivo. PIAS1 acts by delineating histone modifications and DNA methylation to silence the expression of a subset of clinically relevant genes, including breast cancer DNA methylation signature genes such as cyclin D2 and estrogen receptor, and breast tumor suppressor WNT5A. Our studies identify a novel epigenetic mechanism that regulates breast tumorigenesis through selective gene silencing.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Mama/patologia , Carcinogênese/genética , Epigênese Genética/genética , Proteínas Inibidoras de STAT Ativados/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Animais , Linhagem Celular Tumoral , Ciclina D2/genética , Metilação de DNA/genética , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Inativação Gênica , Humanos , Camundongos SCID , Proteínas Proto-Oncogênicas/genética , Receptores de Estrogênio/genética , Ubiquitina-Proteína Ligases/genética , Proteínas Wnt/genética , Proteína Wnt-5aRESUMO
How inflammatory stimuli signal to the nucleus to restrict inflammation is poorly understood. Protein inhibitor of activated STAT1 (PIAS1), a transcriptional regulator that possesses small ubiquitin-related modifier (SUMO) E3 ligase activity, inhibits immune responses by selectively blocking the binding of NF-kappaB and STAT1 to gene promoters. We report here that PIAS1 becomes rapidly phosphorylated on Ser90 residue in response to various inflammatory stimuli. Mutational studies indicate that Ser90 phosphorylation is required for PIAS1 to repress transcription. Upon TNF treatment, wild-type PIAS1, but not the Ser90A mutant, becomes rapidly associated with the promoters of NF-kappaB target genes. Furthermore, IKKalpha, but not IKKbeta, interacts with PIAS1 in vivo and mediates PIAS1 Ser90 phosphorylation, a process that requires the SUMO ligase activity of PIAS1. Our results identify a signaling pathway in which proinflammatory stimuli activate the IKKalpha-mediated sumoylation-dependent phosphorylation of PIAS1 for the immediate repression of inflammatory gene activation.
Assuntos
Quinase I-kappa B/metabolismo , Inflamação/imunologia , Proteínas Inibidoras de STAT Ativados/metabolismo , Animais , Linhagem Celular , Núcleo Celular/metabolismo , Expressão Gênica , Humanos , Quinase I-kappa B/genética , Ligantes , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Fosforilação , Regiões Promotoras Genéticas , Interferência de RNA , RNA Interferente Pequeno , Baço/citologia , Baço/imunologia , Baço/metabolismo , Transcrição GênicaRESUMO
Murine gammaherpesvirus 68 (MHV-68) has been developed as a model for the human gammaherpesviruses Epstein-Barr virus and human herpesvirus 8/Kaposi's sarcoma-associated herpesvirus (HHV-8/KSHV), which are associated with several types of human diseases. Open reading frame 45 (ORF45) is conserved among the members of the Gammaherpesvirinae subfamily and has been suggested to be a virion tegument protein. The repression of ORF45 expression by small interfering RNAs inhibits MHV-68 viral replication. However, the gene product of MHV-68 ORF45 and its function have not yet been well characterized. In this report, we show that MHV-68 ORF45 is a phosphorylated nuclear protein. We constructed an ORF45-null MHV-68 mutant virus (45STOP) by the insertion of translation termination codons into the portion of the gene encoding the N terminus of ORF45. We demonstrated that the ORF45 protein is essential for viral gene expression immediately after the viral genome enters the nucleus. These defects in viral replication were rescued by providing ORF45 in trans or in an ORF45-null revertant (45STOP.R) virus. Using a transcomplementation assay, we showed that the function of ORF45 in viral replication is conserved with that of its KSHV homologue. Finally, we found that the C-terminal 23 amino acids that are highly conserved among the Gammaherpesvirinae subfamily are critical for the function of ORF45 in viral replication.
Assuntos
Gammaherpesvirinae/fisiologia , Proteínas Imediatamente Precoces/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Linhagem Celular , Códon/genética , Sequência Consenso , Cricetinae , Gammaherpesvirinae/genética , Genoma Viral , Dados de Sequência Molecular , Terminação Traducional da Cadeia Peptídica , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Proteínas Virais/genética , Replicação ViralRESUMO
Murine gammaherpesvirus 68 (MHV-68) is genetically related to the human gammaherpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) and Epstein-Barr virus (EBV). It has been proposed as a model for gammaherpesvirus infection and pathogenesis. Open reading frame 31 (ORF31) is conserved among the Beta- and Gammaherpesvirinae subfamily, and there is no known mammalian homologue of this protein. The function of MHV-68 ORF31 and its viral homologues has not yet been determined. We described here a primary characterization of this protein and its requirement for lytic replication. The native MHV-68 ORF31 was detected at peak levels by 24 h postinfection, and the FLAG-tagged and green fluorescent protein fusion ORF31 were localized in the cytoplasm and nucleus in a diffuse pattern. Two independent experimental approaches were then utilized to demonstrate that ORF31 was required for lytic replication. First, small interfering RNA generated against ORF31 expression blocked protein expression and virus production in transfected cells. Then, two-independent bacterial artificial chromosome-derived ORF31-null MHV-68 mutants (31STOP) were generated and found to be defective in virus production in fibroblast cells. This defect can be rescued in trans by MHV-68 ORF31 and importantly by its KSHV homologue. A repair virus of 31STOP was also generated by homologous recombination in fibroblast cells. Finally, we showed that the defect in ORF31 blocked late lytic protein expression. Our results demonstrate that MHV-68 ORF31 is required for viral lytic replication, and its function is conserved in its KSHV homologue.