L10P mutation in DJ-1 gene induced oxidative stress and mitochondrial disfunction.

OBJECTIVE: To investigate the effect of the L10P mutation on the cellular mitochondrial disfunction.

METHODS: Spectrophotometer, flow cytometry and electron microscope was utilized to examine cell viability, reactive oxygen species (ROS), mitochondrial transmembrane potential, complex I activity and mitochondrial morphous of the HEK293 monoclone cell lines, in which wild-type and L10P mutant DJ-1 protein are stably expressed.

RESULTS: Compared with the cell lines expressing empty vector, we found the ROS levels were elevated, the cell viability, mitochondrial transmembrane potential, complex I activity were reduced in the cells expressing L10P mutant DJ-1 protein (P<0.05). We also found mitochondria in these cells were swelling and some mitochondria were vacuolar degeneration. These phenomena were more obvious when rotenone was used. But in the cells expressing wild-type DJ-1, ROS levels were lower, the cell viability, mitochondrial transmembrane potential, and complex I activity were higher than other cell lines (P<0.05), especially under the induction of rotenone. These results suggested that L10P mutant DJ-1 protein probably lost the ability of anti-oxidative stress and affect the normal function of mitochondria.

CONCLUSION: The L10P DJ-1 mutation results in a toxic protein, which lacks the protective function of wild-type protein on mitochondria due to the decrease in the ability of anti-oxidative stress.