Mitochondrial cytochrome c release precedes transmembrane depolarisation and caspase-3 activation during ceramide-induced apoptosis of Jurkat T cells.
Whilst the role of ceramide, a second messenger of the sphingolipid family, in the initiation of receptor-mediated apoptosis is controversial, a growing body of evidence is emerging for a role of ceramide in the amplification of apoptosis via mitochondrial perturbations that culminate in the activation of execution caspases. Treatment of Jurkat T cells with the cell-permeable analog, C(2)-ceramide, resulted in the rapid onset of apoptosis as evidenced by Annexin V-FITC staining of externalised phosphatidylserine residues. Cells bearing this early apoptotic marker had a reduced mitochondrial transmembrane potential (Delta(Psi)m) that was preceded by the release of cytochrome c from mitochondria. Subsequent activation of caspase-3 provides the link between these ceramide-induced mitochondrial changes and execution caspases that ultimately result in the physical destruction of the cell. Collectively these results demonstrate that ceramide signalling results in caspase-mediated apoptosis via mitochondrial cytochrome c release and are further supportive of the role of ceramide in the amplification of apoptosis.
Division of Medicine, University of Tasmania, GPO Box 252-34, Hobart, Tasmania 7001, Australia.
A C
AC
Hearps
J
J
Burrows
C E
CE
Connor
G M
GM
Woods
R M
RM
Lowenthal
S J
SJ
Ragg
D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002518:Ceramides / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D019169:Jurkat Cells; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010718:Phosphatidylserines / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology
D017304:Annexin A5; D002518:Ceramides; D003574:Cytochrome c Group; C064769:N-acetylsphingosine; D010718:Phosphatidylserines; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D016650:Fluorescein-5-isothiocyanate; D013110:Sphingosine