Mitochondrial cytochrome c oxidase subunit III is selectively down-regulated by aluminum exposure in PC12S cells

Aluminum (Al) has been implicated in several neurological diseases including dialysis dementia and Alzheimer's disease (AD). One possible mechanism of Al neurotoxicity could involve alteration of mitochondrial gene expression. We exposed PC12 cells to 0.1-100 μM AlCl 3 for 6h at pH 7.4. Internalized Al, measured by atomic absorption spectrometry, was linearly proportional to the extracellular Al concentration. Northern blot analyses showed that cytochrome c oxidase subunit III (COX III) mRNA was significantly reduced by 70% after addition of I μM AlCl 3 . Higher concentrations of AlCl 3 did not show a significant further effect. These results suggest that Al neurotoxicity involves a specific impairment of cytochrome c oxidase.