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Proyecto

Transcription factor interplay as a driving force in the hepatic response to fasting and its dysregulation in metabolic disease
 

Brazil
Middle East
Identificador del Proyecto
109155
Total del financiamiento
CAD 670,000.00
Funcionario del IDRC
Fabiano Santos
Estado de Proyecto
Completed
Fecha de finalización
Duración
36 meses

Programas y alianzas

Principales instituciones

Resumen

Metabolic diseases, including diabetes, obesity, and non-alcoholic fatty liver disease are reaching epidemic levels worldwide. Improper cellular energy production, storage, and use underlie many of these conditions.Más información

Metabolic diseases, including diabetes, obesity, and non-alcoholic fatty liver disease are reaching epidemic levels worldwide. Improper cellular energy production, storage, and use underlie many of these conditions. The enzymes that control glucose, fat, and ketone body production in the liver are under the control of numerous proteins called transcription factors. In response to fasting, a specific series of transcription factors are required to ensure proper activation of the enzymes that are important for maintaining fuel levels in the absence of an external food source.

In this project, researchers will use specific gene knockout mouse models of these transcription factors, in combination with state-of-the-art DNA and RNA sequencing technologies, to uncover the importance of these transcription factors in modifying the basic physiologic response to fasting and how these are modified in disease. The team will also test novel small molecules that target these transcription factors for their ability to restore the proper fasting response in a mouse model of diet-induced obesity.

The project was selected for funding through the fifth research competition of the Joint Canada-Israel Health Research Program. This initiative is a partnership between IDRC, the Canadian Institutes of Health Research, the Israel Science Foundation, and the Azrieli Foundation.

Publicaciones

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Article
Idioma:

Inglés

Resumen

The accessibility of different chromatin regions to transcription factors and other DNA-binding proteins is a critical determinant of cell function. Here, we detail a modified assay for transposase-accessible chromatin sequencing (ATAC-seq) protocol which measures chromatin accessibility genome wide. We describe nuclei isolation, tagmentation, PCR amplification, and pre- and post sequencing quality control. Our protocol is optimized for the liver, a tissue where nuclei isolation requires distinct steps. We provide two detailed vignettes: one for bulk ATAC-seq and another for single-nuclei ATAC-seq. Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Autores
Korenfeld, Noga
Artículo
Resumen

During fasting, hepatocytes produce glucose in response to hormonal signals. Glucagon and glucocorticoids are principal fasting hormones that cooperate in regulating glucose production via gluconeogenesis. However, how these hormone signals are integrated and interpreted to a biological output is unknown. Here, we use genome-wide profiling of gene expression, enhancer dynamics and transcription factor (TF) binding in primary mouse hepatocytes to uncover the mode of cooperation between glucagon and glucocorticoids. We found that compared to a single treatment with each hormone, a dual treatment directs hepatocytes to a pro-gluconeogenic gene program by synergistically inducing gluconeogenic genes. The cooperative mechanism driving synergistic gene expression is based on ‘assisted loading’ whereby a glucagon-activated TF (cAMP responsive element binding protein; CREB) leads to enhancer activation which facilitates binding of the glucocorticoid receptor (GR) upon glucocorticoid stimulation. Glucagon does not only activate single enhancers but also activates enhancer clusters, thereby assisting the loading of GR also across enhancer units within the cluster. In summary, we show that cells integrate extracellular signals by an enhancer-specific mechanism: one hormone-activated TF activates enhancers, thereby assisting the loading of a TF stimulated by a second hormone, leading to synergistic gene induction and a tailored transcriptional response to fasting.

Autores
Goldberg, Dana
Resultados de la investigación Opens in new tab

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Alianzas

Joint Canada-Israel Health Research Program

Canada’s International Development Research Centre, in partnership with the Azrieli Foundation, the Canadian Institutes of Health Research (CIHR) and the Israel Science Foundation (ISF), is supporting cutting-edge biomedical and global health research.