Evolutionarily conserved long-chain Acyl-CoA synthetases regulate membrane composition and fluidity

The human AdipoR1 and AdipoR2 proteins, as well as their C. elegans homolog PAQR-2, protect against cell membrane rigidification by exogenous saturated fatty acids by regulating phospholipid composition. Here, we show that mutations in the C. elegans gene acs-13 help to suppress the phenotypes of paqr-2 mutant worms, including their characteristic membrane fluidity defects. acs-13 encodes a homolog of the human acyl-CoA synthetase ACSL1, and localizes to the mitochondrial membrane where it likely activates long chains fatty acids for import and degradation. Using siRNA combined with lipidomics and membrane fluidity assays (FRAP and Laurdan dye staining) we further show that the human ACSL1 potentiates lipotoxicity by the saturated fatty acid palmitate: silencing ACSL1 protects against the membrane rigidifying effects of palmitate and acts as a suppressor of AdipoR2 knockdown, thus echoing the C. elegans findings. We conclude that acs-13 mutations in C. elegans and ACSL1 knockdown in human cells prevent lipotoxicity by promoting increased levels of polyunsaturated fatty acid-containing phospholipids.Peer reviewe

Diseño y ejecución de arquitectura de descarga, modelamiento y análisis de datos para ampliar servicios en una empresa de tecnología

Memoria para optar al título de Ingeniero Civil IndustrialEl propósito de este proyecto es diseñar e implementar una arquitectura de descarga, la cual contendrá dentro de sus capas un modelo de datos que optimice el trabajo con ellos, para el posterior análisis de los datos. La finalidad es hacer que una empresa de Tecnología, que se desenvuelve en el negocio de servicio de emisión de boletas electrónicas, posea un nuevo servicio hacia sus clientes, en conjunto con poseer una base de datos actualizada diariamente para lanzar nuevos productos hacia sus clientes en el futuro, mejorando así su propuesta de valor. Para ello se diseñó e implementó una arquitectura de descarga de cinco capas. La primera capa corresponde a la fuente de datos, siendo, es este caso, la plataforma de Servicios de Impuestos Internos (SII). Por medio de web scraping se cuantificó la cantidad de archivos disponibles para descargar dado un horizonte fijo de tiempo. La segunda corresponde a la extracción, transformación y carga de datos, en donde se utilizó web scraping por medio de Selenium para recaudar la información luego de diseñar un algoritmo de descarga; la información fue transformada en diccionarios y cargada a una base de datos en PostgreSQL. La tercera capa consistió en el modelo de datos para que el acceso a la información fuese posible por medio de consultas óptimas. Se eligió un modelo tipo estrella dado la naturaleza de los datos recolectados y se crearon tablas destinadas para el registro del proceso de descarga. La cuarta etapa consistió en el análisis de datos, en donde se procedió a realizar una plantilla de un dashboard por medio de Power BI, en donde, tras ingresar un datamart de un cliente de un año, entrega un análisis general y específico en base a su información. En este, el cliente puede filtrar por tipo y origen de documento tributario, razón social de sus clientes, ver los productos más vendidos según sus facturas electrónicas, sus clientes más importantes, entre otras cosas. La quinta capa corresponde a la propuesta de servicio, siendo, es este caso, decisiones que los clientes pueden tomar una vez tenga acceso al dashboard de la cuarta capa. Terminado el trabajo de título, se le entregó a la empresa un proceso automatizado capaz de extraer los documentos electrónicos de sus clientes, alimentar un modelo de datos estandarizado y optimizado y construir una serie de reportes que dan visibilidad a indicadores de gestión. Esto permite a la empresa ampliar sus servicios y mejorar su oferta de valor

Identification of TORC1 and TORC2 upstream regulators

All eukaryote cells, and especially singled celled species, monitor their environment and use this information to appropriately adjust their intracellular physiology. In Saccharomyces cerevisiae AGC kinase family members appear to be a major link between environmental cues and the cell growth machinery. However, how environmental cues impinge upon Pkh1/2, TORC1 and TORC2 remains a mystery. We found that TORC1, TORC2 and Pkh1/2 are positively regulated by nutrient quantity and quality. Moreover, in a complementary, hypothesis-based approach we found that regulation of TORC2 downstream of plasma membrane stress is mediated by the Slm1/2 proteins

Caffeine extends yeast lifespan by targeting TORC1

Dietary nutrient limitation (dietary restriction) is known to increase lifespan in a variety of organisms. Although the molecular events that couple dietary restriction to increased lifespan are not clear, studies of the model eukaryote Saccharomyces cerevisiae have implicated several nutrient-sensitive kinases, including the target of rapamycin complex 1 (TORC1), Sch9, protein kinase A (PKA) and Rim15. We have recently demonstrated that TORC1 activates Sch9 by direct phosphorylation. We now show that Sch9 inhibits Rim15 also by direct phosphorylation. Treatment of yeast cells with the specific TORC1 inhibitor rapamycin or caffeine releases Rim15 from TORC1-Sch9-mediated inhibition and consequently increases lifespan. This kinase cascade appears to have been evolutionarily conserved, suggesting that caffeine may extend lifespan in other eukaryotes, including man

Systematic lipidomic analysis of yeast protein kinase and phosphatase mutants reveals novel insights into regulation of lipid homeostasis

The regulatory pathways required to maintain eukaryotic lipid homeostasis are largely unknown. We developed a systematic approach to uncover new players in the regulation of lipid homeostasis. Through an unbiased mass spectrometry-based lipidomic screening, we quantified hundreds of lipid species, including glycerophospholipids, sphingolipids, and sterols, from a collection of 129 mutants in protein kinase and phosphatase genes of Saccharomyces cerevisiae. Our approach successfully identified known kinases involved in lipid homeostasis and uncovered new ones. By clustering analysis, we found connections between nutrient-sensing pathways and regulation of glycerophospholipids. Deletion of members of glucose-and nitrogen-sensing pathways showed reciprocal changes in glycerophospholipid acyl chain lengths. We also found several new candidates for the regulation of sphingolipid homeostasis, including a connection between inositol pyrophosphate metabolism and complex sphingolipid homeostasis through transcriptional regulation of AUR1 and SUR1. This robust, systematic lipidomic approach constitutes a rich, new source of biological information and can be used to identify novel gene associations and function

Probing the Global Cellular Responses to Lipotoxicity Caused by Saturated Fatty Acids

Excessive levels of saturated fatty acids are toxic to cells, although the basis for this lipotoxicity remains incompletely understood. Here, we analyzed the transcriptome, lipidome, and genetic interactions of human leukemia cells exposed to palmitate. Palmitate treatment increased saturated glycerolipids, accompanied by a transcriptional stress response, including upregulation of the endoplasmic reticulum (ER) stress response. A comprehensive genome-wide short hairpin RNA (shRNA) screen identified >350 genes modulating lipotoxicity. Among previously unknown genetic modifiers of lipotoxicity, depletion of RNF213, a putative ubiquitin ligase mutated in Moyamoya vascular disease, protected cells from lipotoxicity. On a broader level, integration of our comprehensive datasets revealed that changes in di-saturated glycerolipids, but not other lipid classes, are central to lipotoxicity in this model. Consistent with this, inhibition of ER-localized glycerol-3-phosphate acyltransferase activity protected from all aspects of lipotoxicity. Identification of genes modulating the response to saturated fatty acids may reveal novel therapeutic strategies for treating metabolic diseases linked to lipotoxicity