Apoptotic cell death of cybrid cells bearing Leber's hereditary optic neuropathy mutations is caspase independent.

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disease characterized by selective death of retinal ganglion cells. Three pathogenic mtDNA point mutations induce an impairment of oxidative phosphorylation. We have investigated whether the release of cytochrome c during incubation of LHON cybrids in galactose medium leads to activation of the executive caspase-3 and to alteration of the energetic status of cells. From our research, it can be concluded that apoptotic cell death induced in LHON cybrid by galactose medium is caspase independent. It remains to be explained how the significant fragmentation of intranucleosomal DNA observed in LHON cybrids could also occur in the absence of caspase activation.