Bortom GWAS av fetma: från genetisk association till funktion
Tidsperiod: 2016-01-01 till 2019-12-31
Projektledare: Casimiro Castillejo-Lopez, Casimiro Castillejo-López
Medarbetare: Casimiro Castillejo-Lopez, Casimiro Castillejo-López, Marcel den Hoed
Budget: 4 000 000 SEK
Over the next decades, dramatic increases of obesity and type 2 diabetes are expected in the U.S. and throughout the world. As insulin resistance is a usual intermediate step between obesity, type 2 diabetes and cardiovascular disease, discovery of more efficient ways of preventing, diagnosing and treating obesity and insulin resistance are of uttermost importance.In the past few years, our genome-wide association studies have identified more than 200 genetic loci that are robustly associated with adiposity and/or insulin resistance, but the causal genes and mechanisms are unknown for all but a handful of these loci, and their role in development of insulin resistance has not been studied systematically. This represents a gold mine for in-depth physiological and mechanistic studies, and as insulin resistance is a usual intermediate step between obesity, type 2 diabetes and cardiovascular disease, increased understanding of the links between conditions may lead to new approaches to prevention and treatment that could have a huge public health impact. To establish and characterize genes associated with insulin resistance, we plan a series of experiments in large human cohorts with functional follow-up using zebrafish and cell-based models.We will characterize suggested insulin resistance loci using detailed phenotypic information from large population-based samples (total N=13,811) assessed with dynamic measures of glucose and insulin metabolism, metabolomic, transcriptomic, epigenomic and proteomic profiling together with in silico data on gene regulation and transcription from public resources.Next, we will take about 30 candidate genes forward to our pipeline for efficient characterization in zebrafish using high-throughput visualization techniques and biochemical measurements. We use CRISPR-Cas9 to knockout the homologous genes of a selected number of genes based on results in aim 1 and study the effect of perturbing these genes on several traits related to insulin resistance.Finally, we will prioritize five candidate genes for IR development for mechanistic studies using model systems. We will use CRISPR-Cas9 for gene knockdown in adipocytes and hepatocytes to study glucose, insulin and lipid metabolism, gene expression and metabolic pathways.By performing detailed follow-up analyses of loci hypothesized to be involved in insulin resistance, we expect to establish causal genes and mechanisms of action for several of these loci. The in-depth characterization using in vivo and in vitro models will provide further evidence towards causality and the mechanisms of action, as well as a first evaluation of which could be viable drug targets. Our approach of integrating comprehensive characterization in humans with experiments in functional model systems provides a translational framework, which by design is more likely to yield findings relevant for human biology and medicine. Importantly, we have access to unique study materials, state-of-the art methodology, and have a strong track record of successful collaborations in this field. Our work is anticipated to benefit the scientific community, to lead to new important insights into insulin resistance, cardiovascular disease and type 2 diabetes.