Protection against oxidant-induced apoptosis by exogenous glutathione in Leber hereditary optic neuropathy cybrids.
OBJECTIVE
To use different paradigms of oxidative and metabolic stress in a cellular model of Leber hereditary optic neuropathy (LHON), with the aim of evaluating the efficacy of potentially therapeutic molecules for the treatment of this disease.


METHODS
Cybrids bearing one of the three most common LHON pathogenic mutations (11778/ND4, 3460/ND1, 14484/ND6) were incubated with two compounds known to induce oxidative injury, tert-butyl hydroperoxide (t-BH) and rotenone. To mimic metabolic stress, cells were incubated in a glucose-free medium containing galactose. Cell viability was determined using the MTT assay. To identify the apoptotic type of cell death, nuclear morphology was examined after cell loading with Hoechst. Cellular glutathione (GSH), and oxidized glutathione (GSSG) levels were measured enzymatically.


RESULTS
Incubation with t-BH caused apoptotic cell death of control and LHON cybrids, whereas only LHON cybrids were damaged by rotenone concentrations up to 2.5 muM. Both types of stress caused a marked imbalance in the glutathione levels, but an increase in the GSSG/GSH+GSSG ratio was detected only after rotenone treatment. The efficacy of several antioxidant and antiapoptotic compounds was then assessed in cells exposed to these two oxidative paradigms. Only exogenous GSH remarkably protected the t-BH- and rotenone-treated cybrids from cell death. In contrast, GSH was unable to increase the viability of cybrids exposed to metabolic stress.


CONCLUSIONS
These results suggest that GSH is an effective antioxidant compound to be tested as a potential treatment for LHON.
Ghelli
Anna
A
Dipartimento di Biologia Evoluzionistica Sperimentale, Università di Bologna, Bologna, Italy. ghelli@alma.unibo.it
Porcelli
Anna Maria
AM
Zanna
Claudia
C
Martinuzzi
Andrea
A
Carelli
Valerio
V
Rugolo
Michela
M
D000975:Antioxidants / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival; D005690:Galactose / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism / Q000627:therapeutic use*; D019803:Glutathione Disulfide / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells; D029242:Optic Atrophy, Hereditary, Leber / Q000378:metabolism / Q000517:prevention & control*; D016877:Oxidants / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D012402:Rotenone / Q000633:toxicity*; D014407:Tumor Cells, Cultured; D020122:tert-Butylhydroperoxide / Q000633:toxicity*
D000975:Antioxidants; D016877:Oxidants; D012402:Rotenone; D020122:tert-Butylhydroperoxide; D005978:Glutathione; D019803:Glutathione Disulfide; D005690:Galactose