A bioinformatic analysis identifies circadian expression of splicing factors and time-dependent alternative splicing events in the HD-MY-Z cell line

The circadian clock regulates key cellular processes and its dysregulation is associated to several pathologies including cancer. Although the transcriptional regulation of gene expression by the clock machinery is well described, the role of the clock in the regulation of post-transcriptional processes, including splicing, remains poorly understood. In the present work, we investigated the putative interplay between the circadian clock and splicing in a cancer context. For this, we applied a computational pipeline to identify oscillating genes and alternatively spliced transcripts in time-course high-throughput data sets from normal cells and tissues, and cancer cell lines. We investigated the temporal phenotype of clock-controlled genes and splicing factors, and evaluated their impact in alternative splice patterns in the Hodgkin Lymphoma cell line HD-MY-Z. Our data points to a connection between clock-controlled genes and splicing factors, which correlates with temporal alternative splicing in several genes in the HD-MY-Z cell line. These include the genes DPYD, SS18, VIPR1 and IRF4, involved in metabolism, cell cycle, apoptosis and proliferation. Our results highlight a role for the clock as a temporal regulator of alternative splicing, which may impact malignancy in this cellular model

A Mathematical Model of Lysosomal Ion Homeostasis Points to Differential Effects of Cl- Transport in Ca2+ Dynamics

The establishment and maintenance of ion gradients between the interior of lysosomes and the cytosol are crucial for numerous cellular and organismal functions. Numerous ion transport proteins ensure the required variation in luminal concentrations of the different ions along the endocytic pathway to fit the needs of the organelles. Failures in keeping proper ion homeostasis have pathological consequences. Accordingly, several human diseases are caused by the dysfunction of ion transporters. These include osteopetrosis, caused by the dysfunction of Cl-/H+ exchange by the lysosomal transporter ClC-7. To better understand how chloride transport affects lysosomal ion homeostasis and how its disruption impinges on lysosomal function, we developed a mathematical model of lysosomal ion homeostasis including Ca2+ dynamics. The model recapitulates known biophysical properties of ClC-7 and enables the investigation of its differential activation kinetics on lysosomal ion homeostasis. We show that normal functioning of ClC-7 supports the acidification process, is associated with increased luminal concentrations of sodium, potassium, and chloride, and leads to a higher Ca2+ uptake and release. Our model highlights the role of ClC-7 in lysosomal acidification and shows the existence of differential Ca2+ dynamics upon perturbations of Cl-/H+ exchange and its activation kinetics, with possible pathological consequences

Estrategias de enseñanza y aprendizaje en el currículum: propuesta para el trabajo colaborativo entre el psicopedagogo y pedagogo

Tesis (Psicopedagogia)La siguiente investigación pretende comprender las acciones que implican la Ley Orgánica Constitucional de Enseñanza y el decreto 40 del sector Lenguaje y Comunicación para el desarrollo de la comprensión de lectura. Se pretende que los Objetivos Fundamentales y Contenidos Mínimos Obligatorios se operacionalicen a través del aporte de estrategias de enseñanza y aprendizaje en alumnos de 6° año de Enseñanza General Básica, de los Colegios Southern Cross y Santa Rosa de Lo Barnechea. Para la elección del problema a investigar se toma en cuenta las orientaciones educativas actuales, como temas polémicos de la educación que emanan de esta época, tales como bajo rendimiento en las mediciones curriculares SIMCE y TIMSS. Se visualizan dos aspectos conflictivos, la Reforma Educacional y las estrategias de enseñanza y aprendizaje implícitas en la Reforma. La primera, porque ha implicado cambios metodológicos curriculares, ya que el Decreto 40 significaba un cambio en el qué y cómo aprenden los niños, en el rol del docente, de la familia y la relación de la escuela con la comunidad. Por otra parte, las estrategias de enseñanza y aprendizaje, requieren un proceso de enseñanza, porque no se aprenden espontáneamente, sino que se necesita de un docente capaz de tomar decisiones estratégicas respecto a cómo enseñar y guiar la construcción del conocimiento de sus alumnos, hacia una actuación \Tj progresivamente más autónoma, que les permita gestionar y tomar decisiones en relación con su propio proceso de aprendizaje. Es así como la adquisición de estrategias de aprendizaje se ha convertido, para la escuela, en la principal garantía para "aprender a aprender", es decir, adquirir, pensar, razonar, analizar, organizar y comunicar el conocimiento, un conocimiento que se va construyendo y reconstruyendo de forma continua, que se sustenta en la memoria comprensiva y la participación activa del alumnado el proceso educativo. Esto es uno de los puntos claves para garantizar el desarrollo integral del alumno y la mejora de la calidad educativa

The Core-Clock Gene NR1D1 Impacts Cell Motility In Vitro and Invasiveness in a Zebrafish Xenograft Colon Cancer Model

International audienceMalfunctions of circadian clock trigger abnormal cellular processes and influence tumorigenesis. Using an in vitro and in vivo xenograft model, we show that circadian clock disruption via the downregulation of the core-clock genes BMAL1, PER2, and NR1D1 impacts the circadian phenotype of MYC, WEE1, and TP53, and affects proliferation, apoptosis, and cell migration. In particular, both our in vitro and in vivo results suggest an impairment of cell motility and a reduction in micrometastasis formation upon knockdown of NR1D1, accompanied by altered expression levels of SNAI1 and CD44. Interestingly we show that differential proliferation and reduced tumour growth in vivo may be due to the additional influence of the host-clock and/or to the 3D tumour architecture. Our results raise new questions concerning host–tumour interaction and show that core-clock genes are involved in key cancer properties, including the regulation of cell migration and invasion by NR1D1 in zebrafish xenograft

Early IFN-α signatures and persistent dysfunction are distinguishing features of NK cells in severe COVID-19.

Longitudinal analyses of the innate immune system, including the earliest time points, are essential to understand the immunopathogenesis and clinical course of coronavirus disease (COVID-19). Here, we performed a detailed characterization of natural killer (NK) cells in 205 patients (403 samples; days 2 to 41 after symptom onset) from four independent cohorts using single-cell transcriptomics and proteomics together with functional studies. We found elevated interferon (IFN)-α plasma levels in early severe COVD-19 alongside increased NK cell expression of IFN-stimulated genes (ISGs) and genes involved in IFN-α signaling, while upregulation of tumor necrosis factor (TNF)-induced genes was observed in moderate diseases. NK cells exert anti-SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) activity but are functionally impaired in severe COVID-19. Further, NK cell dysfunction may be relevant for the development of fibrotic lung disease in severe COVID-19, as NK cells exhibited impaired anti-fibrotic activity. Our study indicates preferential IFN-α and TNF responses in severe and moderate COVID-19, respectively, and associates a prolonged IFN-α-induced NK cell response with poorer disease outcome

Complement activation induces excessive T cell cytotoxicity in severe COVID-19.

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16+ T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16+ T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16+ T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16+ cytotoxic T cells. Proportions of activated CD16+ T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19