RESUMEN
Diabetic Macular Edema (DME) is the most common sight-threatening complication of type 2 diabetes. Optical Coherence Tomography (OCT) is the most useful imaging technique to diagnose, follow up, and evaluate treatments for DME. However, OCT exam and devices are expensive and unavailable in all clinics in low- and middle-income countries. Our primary goal was therefore to develop an alternative method to OCT for DME diagnosis by introducing spectral information derived from spontaneous electroretinogram (ERG) signals as a single input or combined with fundus that is much more widespread. Baseline ERGs were recorded in 233 patients and transformed into scalograms and spectrograms via Wavelet and Fourier transforms, respectively. Using transfer learning, distinct Convolutional Neural Networks (CNN) were trained as classifiers for DME using OCT, scalogram, spectrogram, and eye fundus images. Input data were randomly split into training and test sets with a proportion of 80 %-20 %, respectively. The top performers for each input type were selected, OpticNet-71 for OCT, DenseNet-201 for eye fundus, and non-evoked ERG-derived scalograms, to generate a combined model by assigning different weights for each of the selected models. Model validation was performed using a dataset alien to the training phase of the models. None of the models powered by mock ERG-derived input performed well. In contrast, hybrid models showed better results, in particular, the model powered by eye fundus combined with mock ERG-derived information with a 91 % AUC and 86 % F1-score, and the model powered by OCT and mock ERG-derived scalogram images with a 93 % AUC and 89 % F1-score. These data show that the spontaneous ERG-derived input adds predictive value to the fundus- and OCT-based models to diagnose DME, except for the sensitivity of the OCT model which remains the same. The inclusion of mock ERG signals, which have recently been shown to take only 5 min to record in daylight conditions, therefore represents a potential improvement over existing OCT-based models, as well as a reliable and cost-effective alternative when combined with the fundus, especially in underserved areas, to predict DME.
Asunto(s)
Diabetes Mellitus Tipo 2 , Retinopatía Diabética , Edema Macular , Humanos , Edema Macular/diagnóstico por imagen , Retinopatía Diabética/diagnóstico por imagen , Diabetes Mellitus Tipo 2/complicaciones , Fondo de Ojo , Tomografía de Coherencia Óptica/métodosRESUMEN
New factors that influence the viral response in HCV non-genotype 2/3 patients must be identified in order to optimize anti-HCV treatment. This multicenter prospective study evaluates the influence of HCV variability and pharmacological parameters on the virological response of these patients to pegylated interferon α2a (peg-IFN-α2a: 180 µg/week) and ribavirin (RBV; 800-1,200 mg/day) for 48 weeks. HCV subtypes were identified by sequencing the NS5B region. Serum RBV and peg-IFN-α2a concentrations were measured at weeks 4 and 12. The 115 patients (67 men; median age = 49, range 31-76) included 64 who had never been treated and 27 co-infected with HIV. The mean baseline HCV RNA was 6.30 ± 0.06 log IU/ml and the HCV genotypes were: G1 (n = 93) with 1a (n = 37) and 1b (n = 50), G4 (n = 20) and G5 (n = 2). Most patients (79/108; 73%) had an early virological response. Independent predictors of an early virological response were interferon naive patients (OR= 2.98, 95% CI: 1.15-7.72) and RBV of >2,200 ng/ml at week 12 (OR = 3.41, 95% CI: 1.31-8.90). Forty of 104 patients (38%) had a sustained virological response. The only independent predictors of a sustained virological response were subtype 1b (OR = 6.82, 95% CI: 1.7-26.8), and HCV RNA <15 IU/ml at week 12 (OR = 25, 95% CI: 6.4-97.6). Thus a serum RBV concentration of >2,200 ng/ml was associated with an early virological response and patients infected with HCV subtype 1b had a better chance of a sustained virological response than did those infected with subtype 1a.
Asunto(s)
Hepacivirus/efectos de los fármacos , Hepacivirus/genética , Hepatitis C Crónica/tratamiento farmacológico , Hepatitis C Crónica/virología , Interferón-alfa/uso terapéutico , Polietilenglicoles/uso terapéutico , Ribavirina/farmacología , Ribavirina/uso terapéutico , Adulto , Anciano , Antivirales/sangre , Antivirales/uso terapéutico , Quimioterapia Combinada , Femenino , Genotipo , Infecciones por VIH/complicaciones , Infecciones por VIH/virología , Humanos , Interferón-alfa/sangre , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Proteínas Recombinantes/sangre , Proteínas Recombinantes/uso terapéutico , Ribavirina/sangre , Resultado del Tratamiento , Carga ViralRESUMEN
The human T-cell leukemia virus type 1 (HTLV-1) Tax protein activates viral transcription through three 21-bp repeats located in the U3 region of the HTLV-1 long terminal repeat and called Tax-responsive elements (TxREs). Each TxRE contains nucleotide sequences corresponding to imperfect cyclic AMP response elements (CRE). In this study, we demonstrate that the bZIP transcriptional factor CREB-2 is able to bind in vitro to the TxREs and that CREB-2 binding to each of the 21-bp motifs is enhanced by Tax. We also demonstrate that Tax can weakly interact with CREB-2 bound to a cellular palindromic CRE motif such as that found in the somatostatin promoter. Mutagenesis of Tax and CREB-2 demonstrates that both N- and C-terminal domains of Tax and the C-terminal region of CREB-2 are required for direct interaction between the two proteins. In addition, the Tax mutant M47, defective for HTLV-1 activation, is unable to form in vitro a ternary complex with CREB-2 and TxRE. In agreement with recent results suggesting that Tax can recruit the coactivator CREB-binding protein (CBP) on the HTLV-1 promoter, we provide evidence that Tax, CREB-2, and CBP are capable of cooperating to stimulate viral transcription. Taken together, our data highlight the major role played by CREB-2 in Tax-mediated transactivation.
Asunto(s)
Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/genética , Regiones Promotoras Genéticas , Proteínas de Saccharomyces cerevisiae , Factores de Transcripción/metabolismo , Activación Transcripcional , Factor de Transcripción Activador 2 , Factor de Transcripción Activador 4 , Sitios de Unión , Proteína de Unión a CREB , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Proteínas de Unión al ADN , Proteínas Fúngicas , Productos del Gen tax/genética , Leucina Zippers , Mutagénesis , Proteínas Nucleares/metabolismo , Unión Proteica , Elementos de Respuesta , Linfocitos T , Secuencias Repetidas Terminales , Transactivadores/metabolismo , Factores de Transcripción/genéticaRESUMEN
Neuroendocrine (NE) differentiation of prostate epithelial/basal cells is a hallmark of advanced, androgen-independent prostate cancer, for which there is no successful therapy. Here we report for the first time on alterations in regulatory volume decrease (RVD) and its key determinant, swelling-activated Cl- current (I(Cl,swell)), associated with NE differentiation of androgen-dependent LNCaP prostate cancer epithelial cells. NE-differentiating regimens, namely, chronic cAMP elevation or androgen deprivation, resulted in generally augmented I(Cl,swell) and enhanced RVD. This occurred as a result of both the increased endogenous expression of ClC-3, which is a volume-sensitive Cl- channel involved, as we show, in I(Cl,swell) in LNCaP (lymph-node carcinoma of the prostate) cells and the weaker negative I(Cl,swell) control from Ca2+ entering via store-dependent pathways. The changes in the RVD of NE-differentiated cells generally mimicked those reported for Bcl-2-conferred apoptotic resistance. Our results suggest that strengthening the mechanism that helps to maintain volume constancy may contribute to better survival rates of apoptosis-resistant NE cells.
Asunto(s)
Andrógenos/fisiología , Canales de Cloruro/metabolismo , Neoplasias Hormono-Dependientes/patología , Neoplasias Hormono-Dependientes/fisiopatología , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/fisiopatología , Apoptosis , Calcio/metabolismo , Diferenciación Celular , Tamaño de la Célula , Células Epiteliales/metabolismo , Células Epiteliales/patología , Humanos , Masculino , Neoplasias Hormono-Dependientes/metabolismo , Técnicas de Placa-Clamp , Neoplasias de la Próstata/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Regulación hacia ArribaRESUMEN
TRPM8 (melastatine-related transient receptor potential member 8), a member of the transient receptor potential (TRP) superfamily of cation channels, has been shown to be a calcium-channel protein. TRPM8 mRNA has also been shown to be overexpressed in prostate cancer and is considered to play an important role in prostate physiology. This study was designed to determine the androgen-regulation mechanisms for TRPM8 mRNA expression and to identify the phenotype of TRPM8-expressing cells in the human prostate. Our findings show that trpm8 gene expression requires a functional androgen receptor. Furthermore, this article argues strongly in favour of the fact that the trpm8 gene is a primary androgen-responsive gene. Single-cell reverse transcriptase PCR and immunohistochemical experiments also showed that the trpm8 gene was mainly expressed in the apical secretory epithelial cells of the human prostate and trpm8 down-regulation occurred during the loss of the apical differentiated phenotype of the primary cultured human prostate epithelial cells. The androgen-regulated trpm8 expression mechanisms are important in understanding the progression of prostate cancer to androgen-independence. These findings may contribute to design a strategy to predict prostate cancer status from the TRPM8 mRNA level. Furthermore, as the TRPM8 channel is localized in human prostate cells, it will be interesting to understand its physiological function in the normal prostate and its potential role in prostate cancer development.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Canales Iónicos/genética , Proteínas de Neoplasias/genética , Neoplasias de la Próstata/genética , Receptores Androgénicos/fisiología , 5-alfa-Dihidroprogesterona/metabolismo , 5-alfa-Dihidroprogesterona/farmacología , Andrógenos/metabolismo , Células Epiteliales/química , Células Epiteliales/metabolismo , Humanos , Canales Iónicos/metabolismo , Masculino , Miocitos del Músculo Liso/química , Miocitos del Músculo Liso/metabolismo , Proteínas de Neoplasias/metabolismo , Regiones Promotoras Genéticas/genética , Próstata/citología , Próstata/metabolismo , Neoplasias de la Próstata/metabolismo , ARN Mensajero/análisis , ARN Mensajero/metabolismo , Receptores Androgénicos/genética , Elementos de Respuesta , Canales Catiónicos TRPM , Células Tumorales CultivadasAsunto(s)
Antiinflamatorios/uso terapéutico , Anticuerpos Monoclonales/efectos adversos , Anticuerpos Monoclonales/uso terapéutico , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Enfermedad de Crohn/tratamiento farmacológico , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Enfermedad Aguda , Adalimumab , Antiinflamatorios/efectos adversos , Anticuerpos Monoclonales Humanizados , Humanos , Infliximab , Masculino , Persona de Mediana EdadRESUMEN
The human I-mfa domain-containing protein (HIC) mRNA produces two protein isoforms, HIC p32 and p40, synthesized from alternative translational initiations. p32 translation is initiated from a standard AUG codon and p40 is an N-terminal extension of p32 generated from an upstream GUG codon. The two isoforms show different subcellular localization: p32 is distributed throughout the cytoplasm whereas p40 can be found both in the cytoplasm and the nucleolus. To investigate the possibility that p40 contains a nucleolus targeting sequence in its N-terminal region, COS cells were transfected with an eukaryotic expression vector coding for green fluorescent protein (GFP) fused to the p40 N terminus. The localization of this fusion protein in the nucleolus indicated that the N-terminal amino acids of p40 probably contain a nucleolar localization signal (NoLS). To find the structural motifs required for nucleolar localization of p40, deletion mutants were expressed in COS cells as fusion polypeptides with GFP. We defined a domain of 19 amino acids near the N terminus that contains an arginine-rich subdomain that conforms to other known NoLS. To demonstrate that this sequence is an authentic NoLS, the sequence was fused to GFP. This fusion protein was observed to migrate into the nucleolus. Taken together, our studies demonstrate that p40 contains a NoLS.
Asunto(s)
Secuencias de Aminoácidos , Nucléolo Celular/metabolismo , Factores Reguladores Miogénicos/química , Factores Reguladores Miogénicos/metabolismo , Transporte de Proteínas , Secuencia de Aminoácidos , Animales , Western Blotting , Línea Celular , Gránulos Citoplasmáticos/metabolismo , Colorantes Fluorescentes/metabolismo , Proteínas Fluorescentes Verdes , Humanos , Proteínas Luminiscentes/metabolismo , Microscopía Confocal , Datos de Secuencia Molecular , Factores Reguladores Miogénicos/genética , Isoformas de Proteínas , Estructura Terciaria de Proteína , ARN Mensajero/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , TransfecciónRESUMEN
We describe here a new family of proteins characterized by a particular cysteine-rich carboxy-terminal domain and involved in gene expression regulation. This family presently includes three members: I-mfa (inhibitor of MyoD family), HIC p40 and HIC p32 (human I-mfa domain-containing protein). I-mfa, by interacting with MyoD family members, represses both transcriptional activation and myogenesis mediated by these factors. HIC two isoforms, HIC p40 and HIC p32, are involved in the positive regulation of Tax-mediated HTLV-I (human T-cell leukemia virus type 1) promoter activation and in the negative regulation of Tat-mediated HIV-1 (human immunodeficiency virus type 1) promoter transcription. The common carboxy-terminal region of HIC p40 and HIC p32, which is clearly involved in these regulations, shares 77% homology with the carboxy-terminal domain of I-mfa. This suggests that I-mfa, HIC p40 and HIC p32 are part of a new family of proteins involved in gene expression regulation and characterized by a specific cysteine-rich carboxy-terminal domain. Moreover, the three proteins present different subcellular localizations: I-mfa and HIC p32 are mainly cytoplasmic while HIC p40 is mainly nucleolar. The specific localization of each member of this new family will be discussed, possibly explaining how they work. Effectively, a mechanism of protein sequestration in a particular compartment, cytoplasm or nucleolus, could be involved in their function, as it is the case for many other proteins. This relationship between sequestration and function regulation will be exemplified for several cellular factors.
Asunto(s)
Proteínas/química , Proteínas/fisiología , Secuencia de Aminoácidos , Compartimento Celular , Núcleo Celular/metabolismo , Cisteína/química , Citoplasma/metabolismo , Regulación de la Expresión Génica , Productos del Gen tax/genética , Humanos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Datos de Secuencia Molecular , Factores Reguladores Miogénicos/química , Factores Reguladores Miogénicos/genética , Factores Reguladores Miogénicos/fisiología , FN-kappa B/metabolismo , Estructura Terciaria de Proteína , Proteínas/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
cAMP response element binding protein-2 (CREB-2) is a basic leucine zipper (bZIP) factor that was originally described as a repressor of CRE-dependent transcription but that can also act as a transcriptional activator. Moreover, CREB-2 is able to function in association with the viral Tax protein as an activator of the human T-cell leukemia virus type I (HTLV-I) promoter. Here we show that CREB-2 is able to interact with C/EBP-homologous protein (CHOP), a bZIP transcription factor known to inhibit CAAT/enhancer-dependent transcription. Cotransfection of CHOP with CREB-2 results in decreased activation driven by the cellular CRE motif or the HTLV-I proximal Tax-responsive element, confirming that CREB-2 and CHOP can interact with each other in vivo.
Asunto(s)
Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Leucina Zippers , Factores de Transcripción/metabolismo , Factor de Transcripción Activador 4 , Animales , Proteínas Potenciadoras de Unión a CCAAT/genética , Células COS , Línea Celular , Núcleo Celular/metabolismo , Chlorocebus aethiops , Regulación Viral de la Expresión Génica , Productos del Gen tat/metabolismo , VIH-1/genética , Virus Linfotrópico T Tipo 1 Humano/genética , Humanos , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae , Factor de Transcripción CHOP , Factores de Transcripción/genética , Transcripción Genética , Técnicas del Sistema de Dos Híbridos , Productos del Gen tat del Virus de la Inmunodeficiencia HumanaRESUMEN
The aim of this work was to study the reactivity of antibodies directed against the N-terminus of p53 protein. First, we analysed the cross-reactivity of anti-p53 antibodies from human, mouse and rabbit sera with peptides derived from human, mouse and Xenopus p53. Next, we characterized more precisely a series of monoclonal antibodies directed against the N-terminal part of p53 and produced by immunizing mice with either full length human or Xenopus p53. For each of these mAbs we localized the epitope recognized on human p53 by the Spot method of multiple peptide synthesis, defined critical residues on p53 involved in the interaction by alanine scanning replacement experiments and determined kinetic parameters using real-time interaction analysis. These antibodies could be divided into two groups according to their epitopic and kinetic characteristics and their cross-reactivity with murine p53. Our results indicate that critical residues involved in the interaction of some of these mAbs with p53 correspond to key residues on p53 involved in its interaction with the mdm2 protein. These antibodies could, therefore, represent powerful tools for the study of p53 regulation.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Epítopos Inmunodominantes/inmunología , Proteínas Nucleares , Proteínas Proto-Oncogénicas/inmunología , Proteína p53 Supresora de Tumor/inmunología , Alanina/inmunología , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/sangre , Anticuerpos Monoclonales/metabolismo , Especificidad de Anticuerpos , Sitios de Unión , Secuencia de Consenso , Reacciones Cruzadas , Mapeo Epitopo , Humanos , Epítopos Inmunodominantes/análisis , Epítopos Inmunodominantes/metabolismo , Cinética , Ratones , Datos de Secuencia Molecular , Péptidos/síntesis química , Péptidos/inmunología , Péptidos/metabolismo , Proteínas Proto-Oncogénicas c-mdm2 , Conejos , XenopusRESUMEN
There is a need for new evaluation of anastomotic aneurysms with increasing use of prosthetic material in aortoiliac reconstructive surgery. 503 lower extremity revascularisations performed between 1972 and 1978 were reviewed. 20 false aneurysms complication of synthetic grafts, operated on from 1972 to 1981 were analysed. A retrospective study on the aorto-iliofemoral prosthesis group (N = 97) was enable to compare patients with and without false aneurysm occurrence with an average follow up of 5 years (3 to 9 years). The management of false aneurysm is discussed. This study suggest that most important etiologic factors are the vascular pattern just below the revascularisation, the anastomotic level, an iterative intervention. Extensive reconstructive procedures on the anastomosis level should be avoided. On the other hand choice of anastomotic procedure (termino-terminal versus latero-lateral anastomosis) and HTA seems to have no deleterious in spite of the findings of other authors.
Asunto(s)
Aneurisma/etiología , Prótesis Vascular/efectos adversos , Enfermedades Vasculares/etiología , Aneurisma/epidemiología , Aneurisma/cirugía , Diagnóstico Diferencial , Humanos , Reoperación , Estudios Retrospectivos , Enfermedades Vasculares/cirugíaRESUMEN
PURPOSE: To assess the etiologies and outcome of liver granulomatosis. METHODS: We analyzed all consecutive liver granulomatosis diagnosed in our internal medicine department from 2000 to 2008. RESULTS: Among 471 liver biopsies, 21 disclosed evidence of liver granulomatosis (4.5%), in sixteen women (76%) and five men, with a median age of 41years. Thirteen were caucasians (62%). At the time of diagnosis, six (28.5%) had isolated abnormal liver function tests, and fifteen (71.4%) presented with clinical manifestations. The underlying cause was identified in 18 cases (85.7%). Eleven (52.3%) were systemic diseases: five (23.8%) primary biliary cirrhosis, two (9.5%) primary sclerosing cholangitis, two (9.5%) common variable immunodeficiency, one (4.7%) Sjögren's syndrome, and one (4.7%) Behçet's disease. Two (9.5%) patients had sarcoidosis. Three (14.3%) liver granulomatosis were of infectious origin (tuberculosis, schistosomiasis, and hepatitis C virus), two (9.5%) were neoplastic (Hodgkin's lymphoma and liver cell adenoma), and three (14.3%) were idiopathic. With a median of 38 months of follow-up, four patients (19%, two common variable immunodeficiency and two sarcoidosis) developed portal hypertension, independently of cirrhosis. One patient died of cryptococcosis. CONCLUSION: In accordance with other European studies, systemic diseases are the main causes of hepatic granulomas. Liver granulomatosis related to common variable immunodeficiency and sarcoidosis are at risk of portal hypertension.
Asunto(s)
Enfermedad de Erdheim-Chester/etiología , Hepatopatías/etiología , Adulto , Síndrome de Behçet/complicaciones , Colangitis Esclerosante/complicaciones , Criptococosis/etiología , Enfermedad de Erdheim-Chester/patología , Femenino , Estudios de Seguimiento , Humanos , Cirrosis Hepática/complicaciones , Cirrosis Hepática Biliar/complicaciones , Hepatopatías/patología , Pruebas de Función Hepática , Masculino , Estudios Retrospectivos , Sarcoidosis/complicaciones , Síndrome de Sjögren/complicacionesRESUMEN
A major clinical problem with PC (prostate cancer) is the cell's ability to survive and proliferate upon androgen withdrawal. Indeed, deregulated cell differentiation and proliferation, together with the suppression of apoptosis, provides the condition for abnormal tissue growth. Here, we examine the differential role of TRP (transient receptor potential) channels in the control of Ca(2+) homoeostasis and growth of PC cells.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Neoplasias de la Próstata/metabolismo , Canales de Potencial de Receptor Transitorio/fisiología , Diferenciación Celular , Proliferación Celular , Retículo Endoplásmico/metabolismo , Humanos , Masculino , Modelos Biológicos , ARN Interferente Pequeño/metabolismo , Canales Catiónicos TRPM/metabolismo , Canales de Potencial de Receptor Transitorio/químicaRESUMEN
The aim of this randomized prospective study was to assess the efficacy and safety of a triple therapy with interferon-alpha (IFN-alpha)-ribavirin-interleukin-2 (IL-2) for the treatment of patients with genotype 1 infection and high viral load nonresponsive to primary IFN-ribavirin therapy. Twenty hepatitis C virus (HCV) genotype 1 patients with high viral load and Metavir fibrosis score >or=2 without HIV co-infection who were previously nonviral responders to standard treatment with IFN plus ribavirin were intensively re-treated with IFN-alpha2a (3 millions (M) IU every 2 days) combined with ribavirin (1000-1200 mg/day) for a 24-week period. Patients were randomized to receive four cycles of subcutaneous injection of IL-2 (3 MIU/day, 5 days a week every 3 weeks) during either the first 12 weeks (group 1, n = 10) or the last 12 weeks (group 2, n = 10) of combination therapy. At the end of triple therapy, six patients (30%) achieved a biochemical response and 4 (20%) a viral response followed by a relapse after triple therapy withdrawal. After 12 weeks of therapy, no difference in viral load was observed between the groups. The decrease in viral load in group 2 was not raised after the addition of IL-2 to IFN plus ribavirin combination therapy. No serious adverse effects were observed. In conclusion, in patients with poor predictive factors of response, the addition of IL-2 to IFN ribavirin combination therapy does not exert a favourable impact on HCV treatment.
Asunto(s)
Antivirales/uso terapéutico , Hepacivirus/genética , Hepatitis C Crónica/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Interleucina-2/uso terapéutico , Ribavirina/uso terapéutico , Antivirales/administración & dosificación , Quimioterapia Combinada , Femenino , Francia , Hepatitis C Crónica/virología , Humanos , Inyecciones Subcutáneas , Interferón alfa-2 , Interferón-alfa/administración & dosificación , Interleucina-2/administración & dosificación , Masculino , Persona de Mediana Edad , Proyectos Piloto , Proteínas Recombinantes , Ribavirina/administración & dosificación , Especificidad de la Especie , Resultado del Tratamiento , Carga ViralRESUMEN
Prostate smooth muscle cells predominantly express alpha1-adrenoceptors (alpha1-AR). alpha1-AR antagonists induce prostate smooth muscle relaxation and therefore they are useful therapeutic compounds for the treatment of benign prostatic hyperplasia symptoms. However, the Ca(2+) entry pathways associated with the activation of alpha1-AR in the prostate have yet to be elucidated. In many cell types, mammalian homologues of transient receptor potential (TRP) genes, first identified in Drosophila, encode TRPC (canonical TRP) proteins. They function as receptor-operated channels (ROCs) which are involved in various physiological processes such as contraction, proliferation, apoptosis, and differentiation. To date, the expression and function of TRPC channels have not been studied in prostate smooth muscle. In fura-2 loaded PS1 (a prostate smooth muscle cell line) which express endogenous alpha1A-ARs, alpha-agonists epinephrine (EPI), and phenylephrine (PHE) induced Ca(2+) influx which depended on the extracellular Ca(2+) and PLC activation but was independent of PKC activation. Thus, we have tested two membrane-permeable analogues of diacylglycerol (DAG), oleoyl-acyl-sn-glycerol (OAG) and 1,2-dioctanoyl-sn-glycerol (DOG). They initiated Ca(2+) influx whose properties were similar to those induced by the alpha-agonists. Sensitivity to 2-aminoethyl diphenylborate (2-APB), SKF-96365 and flufenamate implies that Ca(2+)-permeable channels mediated both alpha-agonist- and OAG-evoked Ca(2+) influx. Following the sarcoplasmic reticulum (SR) Ca(2+) store depletion by thapsigargin (Tg), a SERCA inhibitor, OAG and PHE were both still able to activate Ca(2+) influx. However, OAG failed to enhance Ca(2+) influx when added in the presence of an alpha-agonist. RT-PCR and Western blotting performed on PS1 cells revealed the presence of mRNAs and the corresponding TRPC3 and TRPC6 proteins. Experiments using an antisense strategy showed that both alpha-agonist- and OAG-induced Ca(2+) influx required TRPC3 and TRPC6, whereas the Tg-activated ("capacitative") Ca(2+) entry involved only TRPC3 encoded protein. It may be thus concluded that PS1 cells express TRPC3 and TRPC6 proteins which function as receptor- and store-operated Ca(2+) entry pathways.
Asunto(s)
Calcio/metabolismo , Canales Iónicos/metabolismo , Músculo Liso/citología , Próstata/citología , Receptores Adrenérgicos alfa 1/metabolismo , Agonistas alfa-Adrenérgicos/farmacología , Antagonistas Adrenérgicos alfa/farmacología , Animales , Canales de Calcio/genética , Canales de Calcio/metabolismo , Línea Celular , Diglicéridos/farmacología , Expresión Génica , Receptores de Inositol 1,4,5-Trifosfato , Activación del Canal Iónico/efectos de los fármacos , Activación del Canal Iónico/fisiología , Canales Iónicos/genética , Masculino , ARN Mensajero/análisis , Ratas , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Canales Catiónicos TRPC , Canal Catiónico TRPC6RESUMEN
Regulation of viral genome expression is the result of complex cooperation between viral proteins and host cell factors. We report here the characterization of a novel cellular factor sharing homology with the specific cysteine-rich C-terminal domain of the basic helix-loop-helix repressor protein I-mfa. The synthesis of this new factor, called HIC for Human I-mfa domain-Containing protein, is controlled at the translational level by two different codons, an ATG and an upstream non-ATG translational initiator, allowing the production of two protein isoforms, p32 and p40, respectively. We show that the HIC protein isoforms present different subcellular localizations, p32 being mainly distributed throughout the cytoplasm, whereas p40 is targeted to the nucleolus. Moreover, in trying to understand the function of HIC, we have found that both isoforms stimulate in T-cells the expression of a luciferase reporter gene driven by the human T-cell leukemia virus type I-long terminal repeat in the presence of the viral transactivator Tax. We demonstrate by mutagenesis that the I-mfa-like domain of HIC is involved in this regulation. Finally, we also show that HIC is able to down-regulate the luciferase expression from the human immunodeficiency virus type 1-long terminal repeat induced by the viral transactivator Tat. From these results, we propose that HIC and I-mfa represent two members of a new family of proteins regulating gene expression and characterized by a particular cysteine-rich C-terminal domain.
Asunto(s)
Regulación Viral de la Expresión Génica/genética , VIH-1/genética , Virus Linfotrópico T Tipo 1 Humano/genética , Factores Reguladores Miogénicos/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células COS , Clonación Molecular , ADN Complementario , Duplicado del Terminal Largo de VIH , Datos de Secuencia Molecular , Homología de Secuencia de AminoácidoRESUMEN
The human T-cell leukemia virus type I (HTLV-I) is a causative agent of adult T-cell leukemia. Although the exact mechanism by which HTLV-I contributes to leukemogenesis is still unclear, the Tax protein is thought to play a major role in this process. This 40-kDa polypeptide is able to interact with the tumor suppressor p16(INK4A). Consequently, Tax can activate the signaling pathway that lead to the release of E2F that in turn induces expression of factors required for cell cycle progression. In this paper, we demonstrate that Tax can also activate E2F-mediated transcription independently of p16(INK4A). Indeed, when Tax is coexpressed with the E2F-1 transcription factor in CEM T-cells, which lack expression of p16(INK4A), it strongly potentiates the E2F-dependent activation of a reporter construct driven by a promoter containing E2F binding sites. This stimulation is abrogated by mutations affecting the E2F-binding sites. In addition, Tax also stimulates the transcription of the E2F-1 gene itself. Using Tax mutants that fail to activate either ATF- or NF-kappaB-dependent promoters and different 5' truncation mutants of the E2F-1 promoter, we show that the Tax-dependent transcriptional control of the E2F1 gene involves, at least in part, the ATF binding site located in the E2F-1 promoter.
Asunto(s)
Proteínas Portadoras , Proteínas de Ciclo Celular , Proteínas de Unión al ADN , Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/genética , Linfocitos T/metabolismo , Factores de Transcripción/metabolismo , Activación Transcripcional , Factores de Transcripción Activadores , Sitios de Unión , Proteínas Sanguíneas/metabolismo , Cloruro de Cadmio/farmacología , Línea Celular , Transformación Celular Neoplásica/genética , Cloruros/farmacología , Ciclina E/genética , Factores de Transcripción E2F , Factor de Transcripción E2F1 , Productos del Gen tax/genética , Genes Reporteros , Humanos , Leucemia de Células T/etiología , Leucemia de Células T/genética , Regiones Promotoras Genéticas , Proteína 1 de Unión a Retinoblastoma , Supresión Genética , Tetrahidrofolato Deshidrogenasa/genética , Factor de Transcripción DP1 , Transcripción Genética , Compuestos de Zinc/farmacologíaRESUMEN
Antigenic cross-reactivity, i.e., the capacity of a single antibody to react with apparently dissimilar structures, is a common characteristic of autoantibodies produced during systemic lupus erythematosus (SLE), an autoimmune disease developed by humans and certain strains of mice. Characterization of the extent of cross-reactivity of SLE-related autoantibodies may help identify the immunogenic stimulus, or stimuli, of autoantibody-secreting B-lymphocytes. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was combined with mass spectrometry (MS) to identify cell proteins recognized by a single monoclonal autoantibody (mAb 4B7), derived from an (NZW x BXSB)F1 mouse and selected based on its capacity to react with cardiolipin, that binds to elements in the cytoplasm and nucleoli of HEp-2 cells as assessed by indirect immunofluorescence assay. Proteins from HL-60 extract were separated by 1-D and 2-D PAGE. Western blotting with mAb 4B7 after SDS-PAGE revealed four bands, two intensely labeled at 35 and 32 kDa, and two weaker ones at 20 and 60 kDa; three spots were detected after 2-D PAGE. After trypsin in-gel digestion of the three protein spots, MS yielded representative matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) Reflector or quadrupole-time of flight (Q-TOF) spectra. The three corresponding proteins were identified as the nucleolar phosphoprotein B23 (nucleophosmin), heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) and the 60 kDa Ro/SS-A RNP. Thus, these results showed that 2-D PAGE combined with MS constitutes a sensitive and powerful technique to characterize the full extent of cross-reactivity of a single mAb and may constitute a new approach to further characterize the immunogenic cellular components involved in the breakage of B-cell tolerance observed in SLE.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Autoanticuerpos/inmunología , Autoantígenos/inmunología , Cardiolipinas/inmunología , Ribonucleoproteína Heterogénea-Nuclear Grupo A-B , Proteínas Nucleares/inmunología , Fosfoproteínas/inmunología , ARN Citoplasmático Pequeño , Ribonucleoproteínas/inmunología , Secuencia de Aminoácidos , Animales , Western Blotting/métodos , Extractos Celulares , Reacciones Cruzadas , Electroforesis en Gel Bidimensional/métodos , Electroforesis en Gel de Poliacrilamida/métodos , Técnica del Anticuerpo Fluorescente Indirecta , Glicoproteínas/inmunología , Células HL-60 , Ribonucleoproteínas Nucleares Heterogéneas , Humanos , Ratones , Datos de Secuencia Molecular , Nucleofosmina , Albúmina Sérica Bovina/inmunología , Dodecil Sulfato de Sodio , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Células Tumorales Cultivadas , beta 2 Glicoproteína IRESUMEN
Although the prostate gland is a rich source of alpha1-adreno- (alpha1-AR) and m1-cholino receptors (m1-AChR), the membrane processes associated with their activation in glandular epithelial cells is poorly understood. We used the whole-cell patch-clamp technique to show that the agonists of the respective receptors, phenylephrine (PHE) and carbachol (CCh), activate cationic membrane currents in lymph node carcinoma of the prostate (LNCaP) human prostate cancer epithelial cells, which are not dependent on the filling status of intracellular IP3-sensitive Ca2+ stores, but directly gated by diacylglycerol (DAG), as evidenced by the ability of its membrane permeable analogue, OAG, to mimic the effects of the agonists. The underlying cationic channels are characterized by the weak field-strength Eisenman IV permeability sequence for monovalent cations (PK(25) > PCs(4.6) > PLi(1.4) > PNa(1.0)), and the following permeability sequence for divalent cations: PCa(1.0) > PMg(0.74) > PBa(0.6) > PSr(0.36) > PMn(0.3). They are 4.3 times more permeable to Ca2+ than Na+ and more sensitive to the inhibitor 2-APB than SK&F 96365. RT-PCR analysis shows that DAG-gated members of the transient receptor potential (TRP) channel family, including TRPC1 and TRPC3, are present in LNCaP cells. We conclude that, in prostate cancer epithelial cells, alpha1-ARs and m1-AChRs are functionally coupled to Ca2+-permeable DAG-gated cationic channels, for which TRPC1 and TRPC3 are the most likely candidates.