Peripheral arterial disease (PAD) affects 5 million people in the US and is the primary cause of limb amputations. Exercise remains the single best intervention for PAD, in part thought to be mediated by increases in capillary density. How exercise triggers angiogenesis is not known. PPARγ coactivator (PGC)-1α is a potent transcriptional co-activator that regulates oxidative metabolism in a variety of tissues. We show here that PGC-1α mediates exercise-induced angiogenesis. Voluntary exercise induced robust angiogenesis in mouse skeletal muscle. Mice lacking PGC-1α in skeletal muscle failed to increase capillary density in response to exercise. Exercise strongly induced expression of PGC-1α from an alternate promoter. The induction of PGC-1α depended on β-adrenergic signaling. β-adrenergic stimulation also induced a broad program of angiogenic factors, including vascular endothelial growth factor (VEGF). This induction required PGC-1α. The orphan nuclear receptor ERRα mediated the induction of VEGF by PGC-1α, and mice lacking ERRα also failed to increase vascular density after exercise. These data demonstrate that β-adrenergic stimulation of a PGC-1α/ERRα/VEGF axis mediates exercise-induced angiogenesis in skeletal muscle.
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