Insulin-like growth factor induced signals activate mitochondrial respiration

Résumé 0

From experiments with lower eukaryotes it is known that the metabolic rate and also the rate of aging are tightly controlled by the IGF / insulin signal transduction pathway. The mitochondrial theory of aging implies that an increased metabolic rate leads to increased mitochondrial activity; increased production of reactive oxygen species due to these alterations would speed up the aging process. To address the question if mitochondrial activity is influenced by insulin / IGF signalling, we have established an experimental system to determine the influence of IGF-I dependent signalling on mitochondrial function. We used DU145 prostate cancer cells, known for the intact IGF signal transduction pathway, to address the influence of IGF receptor activation on mitochondrial function by high-resolution respirometry. These experiments revealed that indeed mitochondrial function is regulated by IGF signalling, and up-regulation of respiration seems to require PI3K/AKT signalling, but is independent of IGF effects on cell cycle progression. Collectively these data establish a regulatory cross-talk between insulin / IGF signal transduction and mitochondrial function, two major pathways implicated in controlling the rate of aging.