Efectos del cortisol sobre la dinámica entre la accesibilidad de la cromatina y la expresión génica en tejido muscular de trucha arcoíris (Oncorhynchus mykiss)
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Fecha
2024
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Profesor/a Guía
Facultad/escuela
Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
La acuicultura en Chile es una actividad económica de suma importancia, que ha ido en aumento durante
los últimos años. Chile resalta especialmente en la producción de salmónidos, el segundo productor del
mundo después de Noruega, entre ellos se destaca la trucha arcoíris (Oncorhynchus mykiss). Por esto,
la relevancia de su estudio es esencial para así mejorar las condiciones intensivas de cultivo optimizando
la biomasa de los cultivos acuícolas. Uno de los principales desafíos es la constante exposición de los
peces a diversos factores de estrés, tales como diferencias de temperatura, densidad de cultivo o
infecciones por patógenos, los cuales pueden afectar la homeostasis y el bienestar animal lo cual
impactaría finalmente en la calidad del producto comercializado. La respuesta al estrés en peces implica
la liberación de la hormona glucocorticoide cortisol a través del eje hipotálamo-pituitario-interrenal
(HPI) al torrente sanguíneo. Su mecanismo de acción biológico involucra atravesar la membrana de las
células diana para unirse a receptores intracelulares de glucocorticoides (GR), cuyo complejo se unirá
a elementos de respuesta a glucocorticoides (GRE) en el promotor de genes blanco para regular su
transcripción. Aunque se conoces los efectos catabólicos del cortisol los cuales inducen atrofia muscular
en teleósteos, los mecanismos epigenéticos asociados a la respuesta a estrés aun no son comprendidos
a fondo. El objetivo general de este proyecto fue evaluar los efectos del cortisol sobre la accesibilidad
de la cromatina y la expresión de genes asociados al crecimiento del músculo esquelético de trucha
arcoíris. Para esto, se recolectó tejido muscular de especies juveniles tratadas con cortisol (10 mg/Kg)
y otro grupo control con la solución vehículo por 3 horas, mediante inyección intraperitoneal (n = 6
cada grupo). Se seleccionaron 3 réplicas biológicas por grupo para analizar las regiones accesibles de
cromatina mediante la secuenciación por ensayo de cromatina accesible por transposasa (ATAC-seq),
donde posteriormente se validaron estos efectos analizando la expresión de genes asociados al
crecimiento por PCR en tiempo real. Los resultados indican que cortisol es capaz de inducir cambios en
la estructura de la cromatina, inhibiendo algunos procesos biológicos asociados a la síntesis de proteínas
y vías de señalización de proliferación celular como las MAPKs. Además, cortisol induce positivamente
regiones accesibles de genes asociados con la macroautofagia, la regulación positiva de la señalización
TORC1, y la proteólisis por ubiquitinación mediada por proteosoma, contribuyendo a la inhibición del
crecimiento. Posteriormente, se analizaron los genes sens1, sens2, samtor y cullin-3, de los cuales se
encontraron también sitios GRE en las regiones accesibles de samtor y sens1. Estos resultados pueden
contribuir a generar potenciales biomarcadores epigenéticos a través de la identificación de patrones
específicos de accesibilidad de la cromatina para así mejorar las técnicas de cultivo en la acuicultura.
Aquaculture in Chile is an extremely important economic activity that has been increasing in recent years. Chile especially highlights in the salmonid production, the second largest producer in the world after Norway, among them the rainbow trout (Oncorhynchus mykiss) stands out. Therefore, the relevance of its study is essential to improve intensive farming conditions and optimize the biomass of aquaculture cultures. One of the main challenges is the constant exposure of fish to various stress factors, such as temperature differences, culture density or pathogen infections, which can affect homeostasis and animal welfare, ultimately impacting the quality of the marketed product. The stress response in fish involves the release of the glucocorticoid hormone cortisol through the hypothalamic-pituitary-interrenal (HPI) axis into the bloodstream. Its biological mechanism of action involves crossing the membrane of target cells to bind to intracellular glucocorticoid receptors (GR), which complex will bind to glucocorticoid response elements (GRE) in the promoter of target genes to regulate their transcription. Although the catabolic effects of cortisol are known to induce muscle atrophy in teleost, the epigenetic mechanisms associated with the stress response are not yet fully understood. The general aim of this project was to evaluate the effects of cortisol on chromatin accessibility and gene expression associated with rainbow trout skeletal muscle growth. For this purpose, muscle tissue was collected from juvenile species treated with cortisol (10 mg/kg) and another control group with the vehicle solution for 3 hours, by intraperitoneal injection (n = 6 each group). Three biological replicates per group were selected to analyze the accessible chromatin regions by transposase accessible chromatin assay sequencing (ATAC-seq), where these effects were subsequently validated by analyzing the expression of growth-related genes by real-time PCR. The results indicate that cortisol can induce changes in chromatin structure, inhibiting some biological processes associated with protein synthesis and cell proliferation signaling pathways such as MAPKs. In addition, cortisol positively induces accessible regions of genes associated with macroautophagy, positive regulation of TORC1 signaling, and proteolysis by proteosome-mediated ubiquitination, contributing to growth inhibition. Subsequently, the genes sens1, sens2, samtor and cullin-3 were analyzed, which GRE sites were also found in the accessible regions of samtor and sens1. These results may contribute to generate potential epigenetic biomarkers through the identification of specific chromatin accessibility patterns to improve culture techniques in aquaculture.
Aquaculture in Chile is an extremely important economic activity that has been increasing in recent years. Chile especially highlights in the salmonid production, the second largest producer in the world after Norway, among them the rainbow trout (Oncorhynchus mykiss) stands out. Therefore, the relevance of its study is essential to improve intensive farming conditions and optimize the biomass of aquaculture cultures. One of the main challenges is the constant exposure of fish to various stress factors, such as temperature differences, culture density or pathogen infections, which can affect homeostasis and animal welfare, ultimately impacting the quality of the marketed product. The stress response in fish involves the release of the glucocorticoid hormone cortisol through the hypothalamic-pituitary-interrenal (HPI) axis into the bloodstream. Its biological mechanism of action involves crossing the membrane of target cells to bind to intracellular glucocorticoid receptors (GR), which complex will bind to glucocorticoid response elements (GRE) in the promoter of target genes to regulate their transcription. Although the catabolic effects of cortisol are known to induce muscle atrophy in teleost, the epigenetic mechanisms associated with the stress response are not yet fully understood. The general aim of this project was to evaluate the effects of cortisol on chromatin accessibility and gene expression associated with rainbow trout skeletal muscle growth. For this purpose, muscle tissue was collected from juvenile species treated with cortisol (10 mg/kg) and another control group with the vehicle solution for 3 hours, by intraperitoneal injection (n = 6 each group). Three biological replicates per group were selected to analyze the accessible chromatin regions by transposase accessible chromatin assay sequencing (ATAC-seq), where these effects were subsequently validated by analyzing the expression of growth-related genes by real-time PCR. The results indicate that cortisol can induce changes in chromatin structure, inhibiting some biological processes associated with protein synthesis and cell proliferation signaling pathways such as MAPKs. In addition, cortisol positively induces accessible regions of genes associated with macroautophagy, positive regulation of TORC1 signaling, and proteolysis by proteosome-mediated ubiquitination, contributing to growth inhibition. Subsequently, the genes sens1, sens2, samtor and cullin-3 were analyzed, which GRE sites were also found in the accessible regions of samtor and sens1. These results may contribute to generate potential epigenetic biomarkers through the identification of specific chromatin accessibility patterns to improve culture techniques in aquaculture.
Notas
Tesis (Ingeniera en Biotecnología)
Palabras clave
Trucha Arcoiris, Genética, Cortisol