Stimulation of astrocyte-enriched culture with C2 ceramide increases proenkephalin mRNA: involvement of cAMP-response element binding protein and mitogen activated protein kinases.
In rat astrocyte-enriched culture, C2 ceramide dose- and time-dependently increased proenkephalin (proENK) mRNA; the significant increase began at 6 h after 30 microM C2 ceramide treatment (about 13-fold) and at 12 h after treatment (about 21-fold). In addition, C2 ceramide also increased AP-1 proteins, such as Fra-1, c-Jun, JunB and JunD, and phosphorylation of CREB. The blocking of protein synthesis by cycloheximide (CHX) evokes a further increase of C2 ceramide-induced proENK mRNA and phospho-CREB level, while C2 ceramide-induced increases of AP-1 protein levels were reduced by CHX. The C2 ceramide-induced proENK mRNA expression was not changed significantly by the pretreatment with H89 (a PKA inhibitor), KN62 (a calcium/calmodulin-dependent protein kinase II inhibitor), and PD98059 (an ERK pathway inhibitor). However, calphostin C (a PKC inhibitor) and or SB203580 (a p38 inhibitor) partially but significantly reduced C2 ceramide-induced proENK mRNA expression as well as phospho-CREB level. These results suggest that, in the rat astrocyte-enriched culture, C2 ceramide increases proENK mRNA expression via phosphorylation of CREB rather than the increases of AP-1 protein levels. Additionally, the activations of PKC and p38, but not PKA, calcium/calmodulin-dependent protein kinase II, and ERK, by C2 ceramide play important regulatory roles in C2 ceramide-induced proENK mRNA expression via activating the CREB.
Won
J S
JS
Department of Pharmacology, College of Medicine, Hallym University, 1 Okchun-Dong, Chunchon, Kangwon-Do 200-702, South Korea.
Choi
M R
MR
Suh
H W
HW
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology*; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004745:Enkephalins / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D010766:Phosphorylation; D011498:Protein Precursors / Q000235:genetics*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013449:Sulfonamides; D018808:Transcription Factor AP-1 / Q000378:metabolism
D017362:Cyclic AMP Response Element-Binding Protein; D004745:Enkephalins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D007546:Isoquinolines; C064769:N-acetylsphingosine; D009281:Naphthalenes; D011498:Protein Precursors; D011500:Protein Synthesis Inhibitors; D011725:Pyridines; D012333:RNA, Messenger; D013449:Sulfonamides; D018808:Transcription Factor AP-1; C029992:proenkephalin; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D003513:Cycloheximide; D020928:Mitogen-Activated Protein Kinases; C058819:calphostin C; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D013110:Sphingosine; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one