Etude de la multiplication des prions en culture cellulaire et analyse des formes infectieuses de la protéine PrP

L'agent infectieux et pathogène des Encéphalopathies Spongiformes Transmissibles, ou maladies à prions, est un conformère anormal (riche en feuillets beta et agrégé) de la protéine PrP, s'accumulant spécifiquement dans les cellules infectées. Nous avons tout d'abord développé un test cellulaire permettant de quantifier ces agents infectieux sans recourir à l'inoculation d'animaux. A l'aide cet outil, nous montrons que des cellules chroniquement infectées utilisent la machinerie cellulaire pour être constitutivement sécrétés en association à des microvésicules d'origine endosomale (exosomes). L'efficacité avec laquelle les prions sont secrétés semble varier fortement en fonction de la nature de la souche infectieuse. L'analyse biochimique de la PrP anormale nous a permis d'identifier des formes infectieuses peu agrégées qui pourraient être générées dans le compartiment endosomal.Prions are infectious agents responsible for transmissible spongiform encephalopathies, which are fatal neurodegenerative disorders. These agents are made of a protein (PrPsc) which becomes infectious upon abnormal folding of the normal PrPc protein. In this study, we studied the extracellular release of prions from cells chronically infected with different prion strains and we also analysed the associated abnormal PrP. We first used rabbit RK13 epithelial cells to develop a titration assay in a cell format. This system allows a fast, robust and sensitive quantification of different prion strains without resorting to animal inoculation. We then show that cell cultures infected with several prion strains secrete prions and abnormal PrP in association with microvesicles of endosomal origin (exosomes). However, the effectiveness of this release may depend on the prion strain used. Biochemical analysis of the cellular and extracellular infectious prions led to the characterization of a new form of abnormal PrP. This form is resistant to proteolysis, much less insoluble than classical PrPres and may be small aggregates of PrPres. It may be generated in the endosomal compartment

El silenciamiento de la proteína priónica celular (PrPC) mediante RNA de interferencia (siRNA) reduce la infección por HSV-1 y HSV-2 en células SK-SY5Y

The transmissible spongiform encephalopathies (TSEs) are neurodegenerative and fatal diseases, affecting humans and some other animal species. The most accepted hypothesis suggests that the infectious agent, named “prion”, is composed mainly by the prion protein scrapie (PrPSc) and it corresponds to an abnormal conformation of a host encoded protein, the cellular prion protein (PrPC), which function is still unknown. However, the ubiquitous expression of PrPC and its highly conserved presence among different species suggests it has a very important role in cell functions. In this work, the PrPC in different cell types, including a primary fish cell culture (Oreochromis spp.), was detected. In addition, based on the human PrPC sequence, we designed a short interfering RNA (siRNA) to silence the PRNP gen in neuronal SK-SY5Y cells. The designed siRNA inhibited the PrPC expression along 96 hours posttransfection and the silenced cells were less susceptible to HSV-1 and HSV-2 infections, in comparison to non siRNA-transfected cells.Las encefalopatías espongiformes transmisibles (EETs) son enfermedades neurodegenerativas fatales que afectan a humanos y ciertas especies animales. La hipótesis más aceptada indica que el agente infeccioso, denotado como prion y compuesto principalmente por la Proteína Priónica Scrapie (PrPSc), corresponde a una conformación anormal de una proteína codificada por el huésped denominada Proteína Priónica Celular (PrPC), cuya función es aún desconocida; sin embargo, la expresión ubicua de PrPC así como su elevado grado de conservación entre especies, sugieren un papel importante para esta proteína. En este trabajo se detectó a la PrPC en diferentes tipos celulares incluyendo un cultivo primario de células de peces (Tilapia, Oreochromis spp.). Además, basándonos en la secuencia de la PrPC humana, se diseñó un RNA de interferencia (siRNA) con el fin de silenciar el gen PRNP en células neuronales SK-SY5Y. El siRNA diseñado inhibió la expresión de PrPC a lo largo de las 96 h post-transfección y las células silenciadas fueron menos susceptibles a la infección por HSV-1 y HSV-2, en comparación con células no transfectadas con el siRNA

Aprendizajes Esperados: Una Educación Efectiva con Estrategias en Hábitos de Lectura

The habit of reading is a cornerstone in the learning process, because before it expands a horizon of opportunities for the acquisition of knowledge of our students, it is very useful and fundamental for our daily life, social, emotional, and academic development. From the perspective of Pérez (2018), the development of a reading habit is influenced by elements such as interest, personal preferences, and academic motivation, he also states that reading is a habit that produces pleasure and fun. The present research highlights the benefits that the habit of reading brings to young students of middle and high school education (EMS). In general terms, the methodology used to carry out this study, due to its characteristics, corresponds to a non-experimental, quantitative, correlational research; with which it was possible to collect, through the application of surveys and interviews, the necessary information to assertively reach the objective of this research: "To identify learning strategies that favor the reading habits of second semester students of the Centro de Bachillerato Tecnológico Agropecuario No. 25 and to analyze how it is related to the expected learning of the subjects they are currently studying".El hábito de lectura es pieza angular en el proceso de aprendizaje, pues ante él se expande un horizonte de oportunidades para la adquisición de conocimiento de nuestros educandos, es muy útil y fundamental para nuestra vida diaria, desarrollo social, emocional y académico; desde la perspectiva de Pérez (2018), en el desarrollo de un hábito lector intervienen factores como el interés, las preferencias personales y la motivación académica, además afirma que la lectura es un hábito que proporciona placer y diversión. La presente investigación resalta las bondades que el hábito de la lectura aporta a los jóvenes estudiantes de Educación Media Superior (EMS). En términos generales, la metodología utilizada para la ejecución de este estudio, corresponde por sus características a una investigación no experimental, de corte cuantitativo, correlacional; con la cual se logró recopilar, mediante la aplicación de cuestionarios y entrevistas, la información necesaria para alcanzar de manera asertiva el objetivo de esta exploración: “Establecer estrategias de aprendizaje que favorezcan los hábitos de lectura en alumnos de segundo semestre del Centro de Bachillerato Tecnológico Agropecuario No. 25 y analizar de qué manera se relaciona con el aprendizaje esperado de las asignaturas que cursan actualmente”

Angio-Arquitectura Visceral en 3D mediante Técnica de Plastinación por Corrosión: Visceral angio-arquitecture in 3D throught corrosion plastination technique

The preservation of anatomical structures arises from the embalming and mummification of corpses carriedout by the Egyptian civilization in the past ages until the development of the most modern techniques, which allow learning in anatomy and embryology ciences. Now at qdays plastination by corrosion injection technique allows reproducing the tubular structures in the visors. The aim of the study was the identificationof the visceral architecture in 3D using the technique of plastination by corrosion. For the plastination, freshvisors were selected; pig’s kidneys and lungs and a human placenta, which ones were injected with the polipoxic preparation colored with acrylics until get a expositation of the vascular tree, renal excretory structures and the trachebronquial tree. The results obtained facilitate the process of anatomy’s teachingto establish an analysment of the macroscopic details and the topographic relationship of the structures that comform the anatomical pieces. La preservación de estructuras anatómicas surge desde el embalsamamiento y momificación de cadáveres realizados por la civilización egipcia en la edad antigua hasta el desarrollo de técnicas más modernas, las cuales permiten el aprendizaje en anatomía y embriología. Hoy en día la plastinación mediante técnica de inyección por corrosión que permite reproducir las estructuras tubulares en las vísceras. El objetivo del estudio fue identificar la angio-arquitectura visceral en 3d mediante la técnica de plastinación por corrosión. Para la plastinación se seleccionaron vísceras frescas; riñones y pulmón de ganado porcino y una placenta humana a las cuales se les inyectó la preparación de poliepóxido teñida de colores acrílicos hasta repletar el árbol vascular, las estructuras excretoras renales y el árbol traquepbronquial Los resultados obtenidos falicitan el proceso de enseñanza de la anatomía para establecer un análisis de los detalles macroscópicos y la relación topográfica de las estructuras que conforman las piezas anatómicas

Partial protection of seasonal trivalent inactivated vaccine against novel pandemic influenza A/H1N1 2009: case-control study in Mexico City

Objective To evaluate the association of 2008-9 seasonal trivalent inactivated vaccine with cases of influenza A/H1N1 during the epidemic in Mexico

A Simple, Versatile and Sensitive Cell-Based Assay for Prions from Various Species

Detection and quantification of prion infectivity is a crucial step for various fundamental and applied aspects of prion research. Identification of cell lines highly sensitive to prion infection led to the development of cell-based titration procedures aiming at replacing animal bioassays, usually performed in mice or hamsters. However, most of these cell lines are only permissive to mouse-adapted prions strains and do not allow titration of prions from other species. In this study, we show that epithelial RK13, a cell line permissive to mouse and bank vole prion strains and to natural prion agents from sheep and cervids, enables a robust and sensitive detection of mouse and ovine-derived prions. Importantly, the cell culture work is strongly reduced as the RK13 cell assay procedure designed here does not require subcultivation of the inoculated cultures. We also show that prions effectively bind to culture plastic vessel and are quantitatively detected by the cell assay. The possibility to easily quantify a wider range of prions, including rodent experimental strains but also natural agents from sheep and cervids, should prompt the spread of cell assays for routine prion titration and lead to valuable information in fundamental and applied studies

Meta-analysis of autoimmune regulator-regulated genes in human and murine models: a novel human model provides insights on the role of autoimmune regulator in regulating STAT1 and STAT1-regulated genes

Autoimmune regulator (AIRE) regulates promiscuous expression of tissue-restricted antigens in medullary epithelial cells (mTEC) of the thymus. To understand the diverse effects of AIRE, it is crucial to elucidate the molecular mechanisms underlying the process of AIRE-regulated gene expression. In this study, we generated a recombinant AIRE expression variant of the TEC 1A3 human cell line, TEC 1A3 AIREhi, to determine genes targeted by AIRE, and using microarray analysis, we identified 482 genes showing significant differential expression (P < 0.05; false discovery rate <5%), with 353 upregulated and 129 downregulated by AIRE expression. Microarray data were validated by quantitative PCR, confirming the differential expression of 12 known AIRE-regulated genes. Comparison of AIRE-dependent differential expression in our cell line model with murine datasets identified 447 conserved genes with a number of transcription regulatory interactions, forming several key nodes, including STAT1, which had over 30 interactions with other AIRE-regulated genes. As STAT1 mutations cause dominant chronic mucocutaneous candidiasis and decreased STAT1 levels in monocytes of autoimmune polyglandular syndrome 1 (APS-1) patients, it was important to further characterize AIRE–STAT1 interactions. TEC 1A3AIREhi were treated with the STAT1 phosphorylation inhibitors fludarabine and LLL3 showed that phosphorylated STAT1 (p-STAT1) was not responsible for any of the observed differential expression. Moreover, treatment of TEC 1A3 AIREhi with STAT1 shRNA did not induce any significant variation in the expression of unphosphorylated STAT1 (U-STAT1) downstream genes, suggesting that these genes were directly regulated by AIRE but not via U-STAT1. The novel model system we have developed provides potential opportunities for further analysis of the pathogenesis of (APS-1) and the wider roles of the AIRE gene

Post-Franco Theatre

In the multiple realms and layers that comprise the contemporary Spanish theatrical landscape, “crisis” would seem to be the word that most often lingers in the air, as though it were a common mantra, ready to roll off the tongue of so many theatre professionals with such enormous ease, and even enthusiasm, that one is prompted to wonder whether it might indeed be a miracle that the contemporary technological revolution – coupled with perpetual quandaries concerning public and private funding for the arts – had not by now brought an end to the evolution of the oldest of live arts, or, at the very least, an end to drama as we know it