Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Terapia Genética/efeitos adversos , Subunidade gama Comum de Receptores de Interleucina/genética , Proteínas com Domínio LIM/genética , Leucemia de Células T/genética , Doenças por Imunodeficiência Combinada Ligada ao Cromossomo X , Animais , Camundongos , Camundongos Transgênicos , Timócitos/patologiaRESUMO
Ideopathic myelofibrosis (IMF) is a chronic myeloproliferative disorder resulting in bone marrow fibrosis as a consequence of growth factor release from clonal haematopoiesis. Conventional cytogenetic analysis identifies abnormalities in approximately a third of cases at diagnosis, although rarely uncovers unique, primary genetic events. We have used comparative genomic hybridization (CGH) to study 25 IMF cases and have compared the results with conventional cytogenetics. Metaphase cells were available for analysis in 13 cases, of which seven showed an abnormal karyotype. CGH chromosomal profiles showed imbalances in 21 of 25 cases. The most frequent aberrations were gains of 9p (12 cases), 2q (seven cases), 3p (seven cases), chromosome 4 (seven cases), 12q (seven cases), 13q (eight cases). The main losses were at 17q and occurred in six cases. The results for CGH and cytogenetics were matched for one case only. Investigation of IMF by CGH suggests that genomic aberrations are much more common than has been previously indicated by conventional cytogenetic analysis and occur in the majority of cases. Gains of 9p were the most frequent finding, occurring in 50% of patients and suggests that genes on 9p may play a crucial role in the pathogenesis of IMF.
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 9/genética , Mielofibrose Primária/genética , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Hibridização de Ácido Nucleico/métodos , Reprodutibilidade dos TestesRESUMO
We irradiated different cellular compartments and measured changes in expression of the FOS gene at the mRNA and protein levels. [(3)H]Thymidine and tritiated water were used to irradiate the nucleus and the whole cell, respectively. (125)I-Concanavalin A binding was used to irradiate the cell membrane differentially. Changes in FOS mRNA and protein levels were measured using semi-quantitative RT-PCR and SDS-PAGE Western blotting, respectively. Irradiation of the nucleus or the whole cell at a dose rate of 0.075 Gy/h caused no change in the level of FOS mRNA expression, but modestly (1.5-fold) induced FOS protein after 0.5 h. Irradiation of the nucleus at a dose rate of 0.43 Gy/h induced FOS mRNA by 1.5-fold after 0.5 h, but there was no significant effect after whole-cell irradiation. FOS protein was transiently induced 2.5-fold above control levels 0.5 h after a 0. 43-Gy/h exposure of the nucleus or the whole cell. Irradiation of the cell membrane at a dose rate of 1.8 Gy/h for up to 2 h caused no change in the levels of expression of FOS mRNA or protein, but a dose rate of 6.8 Gy/h transiently increased the level of FOS mRNA 3-fold after 0.5 h. These data demonstrate the complexity of the cellular response to radiation-induced damage at low doses. The lack of quantitative agreement between the transcript and protein levels for FOS suggests a role for post-transcriptional regulation.
Assuntos
Regulação da Expressão Gênica/efeitos da radiação , Proteínas Oncogênicas v-fos/genética , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Núcleo Celular/genética , Núcleo Celular/efeitos da radiação , Humanos , Proteínas Oncogênicas v-fos/biossíntese , Proteínas Oncogênicas v-fos/efeitos da radiação , RNA Mensageiro/biossíntese , RNA Mensageiro/efeitos da radiação , Transdução de Sinais/efeitos da radiação , Trítio , Células Tumorais CultivadasRESUMO
Pericytes are known to communicate with endothelial cells by direct contact and by releasing cytokines such as TGF-beta. There is also strong evidence that pericytes act as regulators of endothelial cell proliferation and differentiation. We have investigated the effect of pericyte-conditioned medium (PCM) on proliferation of human microvascular endothelial cells in vitro, together with the expression of the vasoregulatory molecules, constitutive and inducible nitric oxide synthases (ecNOS and iNOS), and endothelin-1 (ET-1). Expression was measured at the mRNA level using semiquantitative RT-PCR for all three genes and at the protein level for ecNOS and iNOS using Western blotting. Growth curves for HMECs showed that PCM inhibits proliferation, eventually leading to cell death. Exposure to PCM repressed iNOS mRNA expression fivefold after 6 h. A similar, though delayed, reduction in protein levels was observed. ecNOS mRNA was slightly induced at 6 h, though there was no significant change in ecNOS protein. By contrast, ET-1 mRNA was induced 2.3-fold after 6 h exposure to PCM. We conclude that pericytes release a soluble factor or factors that are potent inhibitors of endothelial cell growth and promote vasoconstriction by up-regulating endothelin-1 and down-regulating iNOS.