Mature iPSC-derived astrocytes of an ALS/FTD patient carrying the TDP43A90V mutation display a mild reactive state and release polyP toxic to motoneurons

Astrocytes play a critical role in the maintenance of a healthy central nervous system and astrocyte dysfunction has been implicated in various neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). There is compelling evidence that mouse and human ALS and ALS/FTD astrocytes can reduce the number of healthy wild-type motoneurons (MNs) in co-cultures or after treatment with astrocyte conditioned media (ACM), independently of their genotype. A growing number of studies have shown that soluble toxic factor(s) in the ACM cause non-cell autonomous MN death, including our recent identification of inorganic polyphosphate (polyP) that is excessively released from mouse primary astrocytes (SOD1, TARDBP, and C9ORF72) and human induced pluripotent stem cells (iPSC)-derived astrocytes (TARDBP) to kill MNs. However, others have reported that astrocytes carrying mutant TDP43 do not produce detectable MN toxicity. This controversy is likely to arise from the findings that human iPSC-derived astrocytes exhibit a rather immature and/or reactive phenotype in a number of studies. Here, we have succeeded in generating a highly homogenous population of functional quiescent mature astrocytes from control subject iPSCs. Using identical conditions, we also generated mature astrocytes from an ALS/FTD patient carrying the TDP43A90V mutation. These mutant TDP43 patient-derived astrocytes exhibit key pathological hallmarks, including enhanced cytoplasmic TDP-43 and polyP levels. Additionally, mutant TDP43 astrocytes displayed a mild reactive signature and an aberrant function as they were unable to promote synaptogenesis of hippocampal neurons. The polyP-dependent neurotoxic nature of the TDP43A90V mutation was further confirmed as neutralization of polyP in ACM derived from mutant TDP43 astrocytes prevented MN death. Our results establish that human astrocytes carrying the TDP43A90V mutation exhibit a cell-autonomous pathological signature, hence providing an experimental model to decipher the molecular mechanisms underlying the generation of the neurotoxic phenotype

Aplicación Web de Apoyo Docente

Tesis (Ingeniero de Ejecución en Computación e Informática)El proyecto fue realizado para la Fundación Educacional Santa Teresita, conformada por tres establecimientos educacionales: Liceo Santa Teresita, Escuela Santa Teresita y Colegio Regina Pacis. Esta Fundación desea mejorar los procesos actuales de sus tres establecimientos a través de un sistema online, que a la vez les permita tener más participación en el mundo de la Internet. La solución se basa en la implementación de una aplicación Web, la cual posea distintas funcionalidades que permitan mejorar los procesos internos así como también la participación de la comunidad educacional. Para esto existirá un servidor que almacenará toda la información curricular de los tres establecimientos, con el fin de que usuarios (alumnos y apoderados) puedan hacer consultas desde la página y vean sus notas actuales. A su ves la aplicación contará con un generador de pruebas, el cual utilizará una base de conocimiento que guardará todas las preguntas disponibles para la creación de las pruebas. Este generador permitirá a los docentes crear las pruebas que ellos necesiten realizar señalando los parámetros específicos de cómo quieren que sea dicha prueba. Los docentes serán los encargados de ingresar las preguntas a la base de conocimiento desde la misma página Web. A continuación se presenta el informe de memoria que detalla los distintos procesos que conforman la creación del proyecto

PCR Restriction Fragment Length Polymorphism Analyses of V. Parahaemolyticus MAM-7 Virulence Gene in Clinical and Environmental Strains

Virulent and non-virulent Vibrio parahaemolyticus (V. parahaemolyticus) strains coexist together in seawater. A PCR–restriction fragment length polymorphism (PCR-RFLP) technique could differentiate between clinical (virulent) and environmental V. parahaemolyticus strains. MAM- 7 corresponds to a virulence gene described in V. parahaemolyticus and that participates in initial stages of pathogen gut colonization. The objective of our study is to evaluate if PCR-RFLP analyses of MAM-7 gene can discriminate between clinical and environmental V. parahaemolyticus strains. Ten V. parahaemolyticus clinical isolates and nine V. parahaemolyticus environmental isolates were used to obtain genomic DNA. A 2619 bp PCR product from MAM-7 gene was digested with HindIII and AcuI restriction enzymes revealing a characteristic common pattern in 100% of V. parahaemolyticus clinical isolates. These patterns were absolutely different of those obtained from environmental isolates. PCR of toxin related genes (tdh and trh) showed that only clinical isolates were tdh+. As a conclusion, PCR-RFLP of V. parahaemolyticus MAM-7 gene could discriminate between clinical tdh+ isolates and environmental ones and could complement other diagnostic tools to detect and classify virulent strains. However, it is still necessary to analyze more samples of V. parahaemolyticus. Thus, while these results are promising, this study corresponds to preliminary work

Neuronal Rubicon Represses Extracellular APP/Amyloid β Deposition in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most prevalent age-associated neurodegenerative disease. A decrease in autophagy during aging contributes to brain disorders by accumulating potentially toxic substrates in neurons. Rubicon is a well-established inhibitor of autophagy in all cells. However, Rubicon participates in different pathways depending on cell type, and little information is currently available on neuronal Rubicon’s role in the AD context. Here, we investigated the cell-specific expression of Rubicon in postmortem brain samples from AD patients and 5xFAD mice and its impact on amyloid β burden in vivo and neuroblastoma cells. Further, we assessed Rubicon levels in human-induced pluripotent stem cells (hiPSCs), derived from early-to-moderate AD and in postmortem samples from severe AD patients. We found increased Rubicon levels in AD-hiPSCs and postmortem samples and a notable Rubicon localization in neurons. In AD transgenic mice lacking Rubicon, we observed intensified amyloid β burden in the hippocampus and decreased Pacer and p62 levels. In APP-expressing neuroblastoma cells, increased APP/amyloid β secretion in the medium was found when Rubicon was absent, which was not observed in cells depleted of Atg5, essential for autophagy, or Rab27a, required for exosome secretion. Our results propose an uncharacterized role of Rubicon on APP/amyloid β homeostasis, in which neuronal Rubicon is a repressor of APP/amyloid β secretion, defining a new way to target AD and other similar diseases therapeutically