Phosphoinositide 3-kinase (PI3K) is a key component of the insulin signaling pathway that controls cellular me-tabolism and growth. Loss-of-function mutations in PI3K signaling and other downstream effectors of the insulin signaling pathway extend the lifespan of various model organisms. However, the pro-longevity effect appears to be sex-specific and young mice with reduced PI3K signaling have increased risk of cardiac disease. Hence, it remains elusive as to whether PI3K inhibition is a valid strategy to delay aging and extend healthspan in humans. We recently demonstrated that reduced PI3K activity in cardiomyocytes delays cardiac growth, causing subnormal contractility and cardiopulmonary functional capacity, as well as increased risk of mortality at young age. In stark contrast, in aged mice, experi-mental attenuation of PI3K signaling reduced the age-dependent decline in cardiac function and extended maximal lifespan, suggesting a biphasic effect of PI3K on cardiac health and survival. The cardiac anti-aging effects of reduced PI3K activity coincided with enhanced oxida-tive phosphorylation and required increased autophagic flux. In humans, explanted failing hearts showed in-creased PI3K signaling, as indicated by increased phos-phorylation of the serine/threonine-protein kinase AKT. Hence, late-life cardiac-specific targeting of PI3K might have a therapeutic potential in cardiac aging and related diseases.
Keywords: IGF1; PI3K; aging; autophagy; cardiomyopathy; heart failure; insulin signaling; mitochondrial dysfunction.
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