Opposite regulation of the mitochondrial apoptotic pathway by C2-ceramide and PACAP through a MAP-kinase-dependent mechanism in cerebellar granule cells.
The sphingomyelin-derived messenger ceramides provoke neuronal apoptosis through caspase-3 activation, while the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) promotes neuronal survival and inhibits caspase-3 activity. However, the mechanisms leading to the opposite regulation of caspase-3 by C2-ceramide and PACAP are currently unknown. Here, we show that PACAP prevents C2-ceramide-induced inhibition of mitochondrial potential and C2-ceramide-evoked cytochrome c release. C2-ceramide stimulated Bax expression, but had no effect on Bcl-2, while PACAP abrogated the action of C2-ceramide on Bax and stimulated Bcl-2 expression. The effects of C2-ceramide and PACAP on Bax and Bcl-2 were blocked, respectively, by the JNK inhibitor L-JNKI1 and the MEK inhibitor U0126. L-JNKI1 prevented the alteration of mitochondria induced by C2-ceramide while U0126 suppressed the protective effect of PACAP against the deleterious action of C2-ceramide on mitochondrial potential. Moreover, L-JNKI1 inhibited the stimulatory effect of C2-ceramide on caspase-9 and -3 and prevented C2-ceramide-induced cell death. U0126 blocked PACAP-induced Bcl-2 expression, abrogated the inhibitory effect of PACAP on ceramide-induced caspase-9 activity, and promoted granule cell death. The present study reveals that C2-ceramide and PACAP exert opposite effects on Bax and Bcl-2 through, respectively, JNK- and ERK-dependent mechanisms. These data indicate that the mitochondrial pathway plays a pivotal role in the pro- and anti-apoptotic effects of C2-ceramide and PACAP.
Falluel-Morel
Anthony
A
European Institute for Peptide Research (IFRMP 23), Laboratory of Cellular and Molecular Neuroendocrinology, University of Rouen, Mont-Saint-Aignan, France.
Aubert
Nicolas
N
Vaudry
David
D
Basille
Magali
M
Fontaine
Marc
M
Fournier
Alain
A
Vaudry
Hubert
H
Gonzalez
Bruno J
BJ
D000818:Animals; D000831:Animals, Newborn; D001562:Benzimidazoles; D015153:Blotting, Western / Q000379:methods; D002232:Carbocyanines; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology*; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048670:MAP Kinase Kinase 4; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008959:Models, Neurological; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects*; D009479:Neuropeptides / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013997:Time Factors; D051028:bcl-2-Associated X Protein
C066099:2,3-N-octanoylsphingosine; C495402:Adcyap1 protein, mouse; C495403:Adcyap1 protein, rat; C494827:Bax protein, mouse; C494828:Bax protein, rat; D001562:Benzimidazoles; D002232:Carbocyanines; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; C121624:Mapkbp1 protein, mouse; C064769:N-acetylsphingosine; D009414:Nerve Growth Factors; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; C068624:5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine; D045304:Cytochromes c; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; C506434:Casp9 protein, mouse; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D013110:Sphingosine