PGC1a and Exercise Adaptations in Zebrafish

Fish species display huge differences in physical activity ranging from lethargy to migration of thousands of miles, making them an interesting model for human exercise. Here, we show a remarkable plasticity of zebrafish in response to exercise and induction of PGC1α (encoded by PPARGC1A), a dominant regulator of mitochondrial biogenesis. Forced expression of human PPARGC1A induces mitochondrial biogenesis, an exercise-like gene expression signature, and physical fitness comparable to wild-type animals trained in counter-current swim tunnels. We quantify a stoichiometric induction of the electron transport chain (ETC) in response to exercise or PGC1α expression, identified by a proteomic SWATH-MS workflow. Exercise or PGC1α expression induce the re-organization of the ETC into respiratory supercomplexes, and we show that ndufa4/ndufa4l, previously assigned to complex I, associates to free and supramolecular complex IV in vivo. Thus, zebrafish is a useful and experimentally tractable vertebrate model to study exercise biology, including ETC expression and assembly. RNA-Seq from total RNA of skeletal muscle of adult zebrafish. Transcriptomic profiles of wild-type fish not trained (Lazy_WT), wild-type fish trained in chronic exercise (Trained_WT) and transgenic fish overexpressing PGC1α not trained (Lazy_TG)