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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A114
In response to Fas/Apo-1/CD95 crosslinking or stimumation with cell-permeant
ceramide, Jurkat T cells exhibit a major, early decrease in autofluorescence
at 424±40 nm indicative of the oxidation/depletion of NADH or NADPH.
Based on kinetic studies, cytofluorometric multiparameter analyses and cell
sorting experiments, the NAD(P)H depletion was found to occur simultaneously
with the dissipation of the mitochondrial inner transmembrane potential
(delta-Phi-m), depletion/oxidation of GSH, and intracellular acidification. In
contrast, NAD(P)H depletion becomes detectable well before a number of
additional changes associated with late apoptosis occur: enhanced superoxide
generation, phosphatidyl serine exposure on the cell surface, cytosolic K+
loss, nuclear DNA fragmentation, cellular shrinkage, loss of viability, and
formation of the mitochondrial neo-antigen APO2.7. Overexpression of the
apoptosis-inhibitory proto-oncogene Bcl-2, which is an inhibitor of the
mitochondrial permeability transition (PT) pore, retarded both the
delta-Phi-m disruption and the depletion of NAD(P)H. Similar effects were observed
for the pharmacological PT pore inhibitors bongkrekic acid or cyclosporin A.
Altogether, these data point to a close functional relationship between
mitochondrial and redox changes during early apoptosis.
OXIDATION OF PYRIMIDINE NUCLEOTIDES DURING APOPTOSIS: CLOSE CORRELATION
WITH MITOCHONDRIAL ALTERATIONS, GLUTATHIONE DEPLETION, AND INTRACELLULAR
ACIDIFICATION
Petit PX 1, Métivier D 2, Gendron MC 3, Sureau F 3,
Macioroska Z 4, Kroemer G 2, Koester S 5
1) INSERM U129, ICGM, Faculté de Médecine Cochin Port-Royal,
Paris, France
2) IRC Villejuif,
3) Université Pierre et Marie Curie,
4) Institut Curie,
5) Coulter/Beckman, Paris, France