Oleuropein induces mitochondrial biogenesis and decreases reactive oxygen species generation in cultured avian muscle cells, possibly via an up-regulation of peroxisome proliferator-activated receptor γ coactivator-1α.

Abstract

It has been shown that oleuropein, a phenolic compound in the fruit and leaves of the olive tree (Olea europaea) induces mammalian uncoupling protein 1 (UCP1) expression via an increased secretion of noradrenaline and adrenaline. This study investigated the effects of oleuropein on avian UCP (avUCP) expression as well as genes related to mitochondrial oxidative phosphorylation and biogenesis in cultured avian muscle cells, together with reactive oxygen species generation. Oleuropein induced avUCP as well as peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor-1 (NRF1), mitochondrial transcription factor A (TFAM) and ATP5a1 (a component of mitochondrial adenosine triphosphate synthase) gene expression and cytochrome c oxidase activity, indicating the induction of mitochondrial biogenesis. Sirtuin-1 (SIRT1) gene expression was also up-regulated by this compound, which could contribute to an increase in PGC-1α activity. Oleuropein suppressed the level of superoxide generation per mitochondrion, possibly via the up-regulation of avUCP and manganese superoxide dismutase (MnSOD) expression. Based on these findings, this study is the first to show that oleuropein may induce avUCP expression in avian muscle cells independent of the catecholamines, in which PGC-1α may be involved.