Commitment to apoptosis by GD3 ganglioside depends on opening of the mitochondrial permeability transition pore.
We have studied the effects of GD3 ganglioside on mitochondrial function in isolated mitochondria and intact cells. In isolated mitochondria, GD3 ganglioside induces complex changes of respiration that depend on the substrate being oxidized. However, these effects are secondary to opening of the cyclosporin A-sensitive permeability transition pore and to the ensuing swelling and cytochrome c depletion rather than to an interaction with the respiratory chain complexes. By using a novel in situ assay based on the fluorescence changes of mitochondrially entrapped calcein (Petronilli, V., Miotto, G., Canton, M., Colonna, R., Bernardi, P., and Di Lisa, F. (1999) Biophys. J. 76, 725-734), we unequivocally show that GD3 ganglioside also induces the mitochondrial permeability transition in intact cells and that this event precedes apoptosis. The mitochondrial effects of GD3 ganglioside are selective, in that they cannot be mimicked by either GD1a or GM3 gangliosides, and they are fully sensitive to cyclosporin A, which inhibits both the mitochondrial permeability transition in situ and the onset of apoptosis induced by GD3 ganglioside. These results provide compelling evidence that opening of the permeability transition pore is causally related to apoptosis.
Scorrano
L
L
Consiglio Nazionale delle Ricerche Unit for the Study of Biomembranes and the Departments of Biomedical Sciences, University of Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy.
Petronilli
V
V
Di Lisa
F
F
Bernardi
P
P
D000818:Animals; D017209:Apoptosis; D016572:Cyclosporine / Q000494:pharmacology; D003524:Cyclosporins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005679:G(M3) Ganglioside / Q000494:pharmacology; D005732:Gangliosides / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects*; D007473:Ion Channels; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D010101:Oxygen Consumption / Q000187:drug effects; D010539:Permeability; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured
D003524:Cyclosporins; D005679:G(M3) Ganglioside; D005732:Gangliosides; D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; C021298:ganglioside, GD1a; C026226:ganglioside, GD3; D016572:Cyclosporine