Transcriptional coactivator PGC-1α controls the energy state and contractile function of cardiac muscle

Skeletal and cardiac muscle depend on high turnover of ATP made by mitochondria in order to contract efficiently. The transcriptional coactivator PGC-1 alpha has been shown to function as a major regulator of mitochondrial biogenesis and respiration in both skeletal and cardiac muscle, but this has been based only on gain-of-function studies. Using genetic knockout mice, we show here that, while PGC-1 alpha KO mice appear to retain normal mitochondrial volume in both muscle beds, expression of genes of oxidative phosphorylation is markedly blunted. Hearts from these mice have reduced mitochondrial enzymatic activities and decreased levels of ATR Importantly, isolated hearts lacking PGC-1 alpha have a diminished ability to increase work output in response to chemical or electrical stimulation. As mice lacking PGC-1 alpha age, cardiac dysfunction becomes evident in vivo. These data indicate that PGC-1 alpha is vital for the heart to meet increased demands for ATP and work in response to physiological stimuli.