Epigenomic Remodeling of Metabolism by Exercise through AP-1

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Project Summary/Abstract We want to address how physical exercise remodels metabolism and ameliorates type 2 diabetes. Exercise is a first-line treatment for type 2 diabetes, and exerts its beneficial effects not only by burning off energy but also by causing prolonged metabolic changes through epigenomic regulation of gene expression. Nonbiased identification of key epigenomic players that mediate exercise-induced gene expression changes has not been attempted. Using global nuclear-run on (GRO-seq) and enhancer RNA (eRNA) as functional enhancer markers, we identified activation protein-1 (AP-1) as the dominant transcription factors that drive exercise- induced enhancers in mouse skeletal muscles after bouts of exercise. Loss-of-function screening identified the pivotal role of JunD, an AP-1 factor, in muscle contraction-induced stress response and metabolic changes in fully-differentiated primary myotubes. We will address the in vivo function of JunD/AP-1 in exercise-mediated metabolic remodeling using conditional knockout and overexpression mouse models. We will also characterize the upstream signals that activates JunD/AP-1, determine the genuine target genes and epigenomic changes controlled by JunD/AP-1, and address the conservation of the JunD pathway in human exercise physiology. Together, this work will provide epigenomic insights into the intermediary metabolism system that is shaped by intermittent exercise during natural evolution. This will lay intellectual groundwork for drug discovery programs that aim to maximize the metabolic benefit of physical exercise, especially considering that accumulating epigenome-modifying drugs are available and show promises in treating cancer and many other diseases in clinical trials.