Research ReportOver-expression of the Sirt3 sirtuin Protects neuronally differentiated PC12 Cells from degeneration induced by oxidative stress and trophic withdrawal

- Ectopically expressed Sirt3-myc localizes predominantly to mitochondria in neuronally differentiated PC12 cells.
- Ectopic over-expression of Sirt3-myc decreases mitochondrial membrane potential and decreases basal ROS levels.
- Sirt3-myc over-expression protects neuronally differentiated PC12 cells from OGD and GD insults.
- Sirt3-myc over-expression protects neuronally differentiated PC12 cells from apoptosis induced by trophic withdrawal.
- Sirt3 is a potential target for neuroprotective intervention in peripheral neurons.

Sirt3 is a mitochondrial sirtuin whose deacetylase activity regulates facets of oxidative metabolic efficiency, anti-oxidative capacity, and intra-mitochondrial signaling. In this study, we tested whether the over-expression of a human Sirt3-myc transgene in differentiated PC12 cells, a model of sympathetic catecholaminergic neurons, would affect the sensitivity of these cells to oxidative stress or trophic withdrawal insults. Expression analysis revealed the Sirt3-myc product was expressed as a 45 kDa pro-form, which localized primarily within the cytosol, and a 30 kDa processed form that localized predominantly within mitochondria. When subjected to acute glucose deprivation or acute oxygen-glucose deprivation, differentiated PC12 cells over-expressing Sirt3-myc displayed significantly lower levels of cytotoxicity, both at the end of the insult, and at different times following media reperfusion, than cells transfected with a control plasmid. Further, Sirt3-myc over-expression also protected differentiated PC12 cells from apoptosis induced by trophic withdrawal. Collectively, these data indicate that an elevation of Sirt3 is sufficient to protect neuronal PC12 cells from cytotoxic insults, and add to the growing evidence that Sirt3 could be targeted for neuroprotective intervention.