Insights on Glucocorticoid Receptor Activity Modulation through the Binding of Rigid Steroids

Background: The glucocorticoid receptor (GR) is a transcription factor that regulates gene expression in a ligand-dependent fashion. This modular protein is one of the major pharmacological targets due to its involvement in both cause and treatment of many human diseases. Intense efforts have been made to get information about the molecular basis of GR activity. Methodology/Principal Findings: Here, the behavior of four GR-ligand complexes with different glucocorticoid and antiglucocorticoid properties were evaluated. The ability of GR-ligand complexes to oligomerize in vivo was analyzed by performing the novel Number and Brightness assay. Results showed that most of GR molecules form homodimers inside the nucleus upon ligand binding. Additionally, in vitro GR-DNA binding analyses suggest that ligand structure modulates GRDNA interaction dynamics rather than the receptor's ability to bind DNA. On the other hand, by coimmunoprecipitation studies we evaluated the in vivo interaction between the transcriptional intermediary factor 2 (TIF2) coactivator and different GR-ligand complexes. No correlation was found between GR intranuclear distribution, cofactor recruitment and the homodimerization process. Finally, Molecular determinants that support the observed experimental GR LBD-ligand/TIF2 interaction were found by Molecular Dynamics simulation. Conclusions/Significance: The data presented here sustain the idea that in vivo GR homodimerization inside the nucleus can be achieved in a DNA-independent fashion, without ruling out a dependent pathway as well. Moreover, since at least one GR-ligand complex is able to induce homodimer formation while preventing TIF2 coactivator interaction, results suggest that these two events might be independent from each other. Finally, 21-hydroxy-6,19-epoxyprogesterone arises as a selective glucocorticoid with potential pharmacological interest. Taking into account that GR homodimerization and cofactor recruitment are considered essential steps in the receptor activation pathway, results presented here contribute to understand how specific ligands influence GR behavior. © 2010 Presman et al.Fil:Presman, D.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Alvarez, L.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Levi, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Martí, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Veleiro, A.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Burton, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Pecci, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Validación prospectiva y multicéntrica del ArgenSCORE en la cirugía de reemplazo valvular aórtico. Comparación con el EuroSCORE I y el EuroSCORE II

Introduction: In patients with aortic stenosis and planned aortic valve replacement, an accurate stratification of surgical risk is mandatory to offer the best individual option. Preoperative risk scores have recovered a leading role in the assessment of these patients.Objectives: The aim of this study was to perform a prospective, multicentric validation of the ArgenSCORE in patients with aortic valve replacement and compare its performance with the EuroSCORE I and the EuroSCORE II.Methods: A total of 250 adult patients undergoing aortic valve replacement at four centers ofthe City of Buenos Aires were included in the study from February 2008 to December2012. The ArgenSCORE was compared with the EuroSCORE I and the Euro-SCORE II, evaluating model discrimination with the area under the ROC curve andcalibration power comparing the relation between observed mortality and predictedmortality.Results: The mean age of the validation population (n = 250) was 68.62 ± 13.3 years and overall mortality of was 3.6 %. The ArgenSCORE showed good discrimination power (area under the ROC curve of 0.82) and a good predictive capacity to allocate risk (relation between observed mortality: 3.6 % vs. predicted mortality: 3.39%; p = 0.471).The EuroSCORE I showed poor discrimination power (area under the ROC curve of0.62) and risk overestimation (relation between observed mortality: 3.6 % vs. predictedmortality: 5.58 %; p < 0.0001). The EuroSCORE II showed an acceptable discrimination power (area under the ROC curve of 0.76), though lower than that of the ArgenSCORE, but a significant underestimation of predicted risk (relation betwee nobserved mortality: 3.6 % vs. predicted mortality: 1.64 %; p < 0.0001).Conclusions: The ArgenSCORE evidenced adequate excellent ability to predict mortality inpatients undergoing AVR aortic valve replacementsurgery. This local model demonstrated good discrimination power and better calibration compared to with the European models, as the EuroSCORE I overestimated and the EuroSCORE II underestimatedpredicted risk.IntroducciónLos modelos de riesgo preoperatorios hanrecobrado un papel protagónico en la evaluación de pacientes para un eventual reemplazovalvular aórtico (RVA).ObjetivosValidarel AgenSCORE en forma prospectiva y multicéntrica en pacientes con RVA y comparar su rendimiento con el EuroSCORE I y el EuroSCOREII.Material y métodosSeincluyeron 250 pacientes consecutivos con RVA en 4 centros de Buenos Aires, desde Febrero 2008 hasta Diciembre 2012. Se comparó el rendimiento del ArgenSCORE, EuroSCORE I y EuroSCORE II, evaluando la discriminación mediante el área bajo la curva ROC y el poder de calibración comparando larelación entre mortalidad observada / mortalidad predicha.ResultadosLapoblación de validación incluyó 250 pacientes, con  edad media de 68.62 ± 13.3 años y mortalidadglobal del 3,6 %. El ArgenSCORE mostró buen poder de discriminación, curva ROC:0,82, y buena capacidad para asignar riesgo, relación mortalidad observada (3,6% versus mortalidad predicha 3,39 %; p= 0,471). El EuroSCORE I mostró bajo poderdiscriminativo, curva ROC: 0,62 y además, sobrevaloró el riesgo estimado,relación mortalidad observada (3,6 % versus mortalidad predicha 5,58 %; p <0,0001).El EuroSCORE II mostró aceptable capacidad discriminativa, curva ROC: 0,76,  aunque menor al del ArgenSCORE, pero mostró unasignificativa subvaloración del riesgo estimado, relaciónmortalidad observada (3,6 % versus  mortalidadpredicha 1,64 %; p <0,0001)ConclusionesEl ArgenSCORE demostrótener un excelente rendimiento en pacientes operados con RVA. Este modelo localmostró buen poder de discriminación y una mejor calibración comparado a losmodelos europeos, ya que el riesgo estimado fue sobrevalorado por el EuroSCOREI y subvalorado por EuroSCORE II

Fish oil and postoperative atrial fibrillation : the Omega-3 Fatty Acids for Prevention of Post-operative Atrial Fibrillation (OPERA) randomized trial

Context: Postoperative atrial fibrillation or flutter (AF) is one of the most common complications of cardiac surgery and significantly increases morbidity and health care utilization. A few small trials have evaluated whether long-chain n-3-polyunsaturated fatty acids (PUFAs) reduce postoperative AF, with mixed results. Objective: To determine whether perioperative n-3-PUFA supplementation reduces postoperative AF. Design, Setting, and Patients: The Omega-3 Fatty Acids for Prevention of Postoperative Atrial Fibrillation (OPERA) double-blind, placebo-controlled, randomized clinical trial. A total of 1516 patients scheduled for cardiac surgery in 28 centers in the United States, Italy, and Argentina were enrolled between August 2010 and June 2012. Inclusion criteria were broad; the main exclusions were regular use of fish oil or absence of sinus rhythm at enrollment. Intervention: Patients were randomized to receive fish oil (1-g capsules containing 65840 mg n-3-PUFAs as ethyl esters) or placebo, with preoperative loading of 10 g over 3 to 5 days (or 8 g over 2 days) followed postoperatively by 2 g/d until hospital discharge or postoperative day 10, whichever came first. Main Outcome Measure: Occurrence of postoperative AF lasting longer than 30 seconds. Secondary end points were postoperative AF lasting longer than 1 hour, resulting in symptoms, or treated with cardioversion; postoperative AF excluding atrial flutter; time to first postoperative AF; number of AF episodes per patient; hospital utilization; and major adverse cardiovascular events, 30-day mortality, bleeding, and other adverse events. Results: At enrollment, mean age was 64 (SD, 13) years; 72.2% of patients were men, and 51.8% had planned valvular surgery. The primary end point occurred in 233 (30.7%) patients assigned to placebo and 227 (30.0%) assigned to n-3-PUFAs (odds ratio, 0.96 [95% CI, 0.77-1.20]; P=.74). None of the secondary end points were significantly different between the placebo and fish oil groups, including postoperative AF that was sustained, symptomatic, or treated (231 [30.5%] vs 224 [29.6%], P=.70) or number of postoperative AF episodes per patient (1 episode: 156 [20.6%] vs 157 [20.7%]; 2 episodes: 59 [7.8%] vs 49 [6.5%]; 653 episodes: 18 [2.4%] vs 21 [2.8%]) (P=.73). Supplementation with n-3-PUFAs was generally well tolerated, with no evidence for increased risk of bleeding or serious adverse events. Conclusion: In this large multinational trial among patients undergoing cardiac surgery, perioperative supplementation with n-3-PUFAs, compared with placebo, did not reduce the risk of postoperative AF. Trial Registration: clinicaltrials.gov Identifier: NCT0097048

GWAS analysis implicates NF-κB-mediated induction of inflammatory T cells in multiple sclerosis

To identify genes and biologically relevant pathways associated with risk to develop multiple sclerosis (MS), the Genome-Wide Association Studies noise reduction method (GWAS-NR) was applied to MS genotyping data. Regions of association were defined based on the significance of linkage disequilibrium blocks. Candidate genes were cross-referenced based on a review of current literature, with attention to molecular function and directly interacting proteins. Supplementary annotations and pathway enrichment scores were generated using The Database for Annotation, Visualization and Integrated Discovery. The candidate set of 220 MS susceptibility genes prioritized by GWAS-NR was highly enriched with genes involved in biological pathways related to positive regulation of cell, lymphocyte and leukocyte activation (P=6.1E-15, 1.2E-14 and 5.0E-14, respectively). Novel gene candidates include key regulators of NF-κB signaling and CD4+ T helper type 1 (Th1) and T helper type 17 (Th17) lineages. A large subset of MS candidate genes prioritized by GWAS-NR were found to interact in a tractable pathway regulating the NF-κB-mediated induction and infiltration of pro-inflammatory Th1/Th17 T-cell lineages, and maintenance of immune tolerance by T-regulatory cells. This mechanism provides a biological context that potentially links clinical observations in MS to the underlying genetic landscape that may confer susceptibility