Ceramide pathways modulate ethanol-induced cell death in astrocytes.
We showed previously that alcohol exposure during in vivo brain development induced astroglial damage and caused cell death. Because ceramide modulates a number of biochemical and cellular responses to stress, including apoptosis, we now investigate whether ethanol-induced cell death in astrocytes is mediated by ceramide signalling pathways triggering apoptosis. Here we show that both ethanol and ceramide are able to induce apoptotic death in cultured astrocytes, in a dose-dependent manner, and that C2-ceramide addition potentiates the apoptotic effects of ethanol. Cell death induced by ethanol is associated with stimulation of neutral and acidic sphingomyelinase (SMase) and ceramide generation, as well as with activation of stress-related kinases, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38) and extracellular signal-regulated kinase (ERK) pathways. We also provide evidence for the participation of JNK and p38 in ethanol-induced cell death, because pharmacological inhibitors of these kinases largely prevent the apoptosis induced by ethanol or by ethanol and C2-ceramide. Furthermore, we show that ethanol-induced ERK activation triggers the stimulation of cyclo-oxygenase-2 (COX-2) and the release of prostaglandin E2, and that blockade of the mitogen-activated protein kinase kinase (MEK)/ERK pathway by PD98059 abolishes the up-regulation of COX-2 induced by ethanol plus ceramide, and decreases the ethanol-induced apoptosis. These results strongly suggest that ethanol is able to stimulate the SMase-ceramide pathway, leading to the activation of signalling pathways implicated in cell death. These findings provide an insight into the mechanisms involved in ethanol-induced astroglial cell death during brain development.
Pascual
María
M
Instituto de Investigaciones Citológicas Centro Investigación Hospital 'La Fe', Valencia, Spain.
Valles
Soraya L
SL
Renau-Piqueras
Jaime
J
Guerri
Consuelo
C
D000581:Amidohydrolases / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects*; D001921:Brain / Q000166:cytology; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D016923:Cell Death; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000494:pharmacology; D055572:Ceramidases; D002851:Chromatography, High Pressure Liquid; D020756:Coatomer Protein / Q000378:metabolism; D003124:Colorimetry / Q000379:methods; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D000431:Ethanol / Q000494:pharmacology*; D015151:Immunoblotting; D066298:In Vitro Techniques; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D004676:Myelin Basic Protein / Q000378:metabolism; D010168:Palmitates / Q000494:pharmacology; D011233:Precipitin Tests; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism*; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism
D002352:Carrier Proteins; D002492:Central Nervous System Depressants; D020756:Coatomer Protein; D004791:Enzyme Inhibitors; D004676:Myelin Basic Protein; C064769:N-acetylsphingosine; D010168:Palmitates; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D000431:Ethanol; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D013108:Sphingomyelin Phosphodiesterase; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D000581:Amidohydrolases; D055572:Ceramidases; D020696:rab5 GTP-Binding Proteins; D015232:Dinoprostone; D013110:Sphingosine