Stimulation of astrocyte-enriched culture with C2 ceramide increases proenkephalin mRNA: involvement of cAMP-response element binding protein and mitogen activated protein kinases

Brain Res. 2001 Jun 8;903(1-2):207-15. doi: 10.1016/s0006-8993(01)02452-0.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / analogs & derivatives
  • 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / pharmacology
  • Animals
  • Astrocytes / cytology
  • Astrocytes / enzymology*
  • Cells, Cultured
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Cycloheximide / pharmacology
  • Enkephalins / genetics*
  • Enzyme Inhibitors / pharmacology
  • Flavonoids / pharmacology
  • Gene Expression / drug effects
  • Imidazoles / pharmacology
  • Isoquinolines / pharmacology
  • Mitogen-Activated Protein Kinases / metabolism*
  • Naphthalenes / pharmacology
  • Phosphorylation
  • Protein Precursors / genetics*
  • Protein Synthesis Inhibitors / pharmacology
  • Pyridines / pharmacology
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Sphingosine / analogs & derivatives
  • Sphingosine / pharmacology*
  • Stimulation, Chemical
  • Sulfonamides*
  • Transcription Factor AP-1 / metabolism

Substances

  • Cyclic AMP Response Element-Binding Protein
  • Enkephalins
  • Enzyme Inhibitors
  • Flavonoids
  • Imidazoles
  • Isoquinolines
  • N-acetylsphingosine
  • Naphthalenes
  • Protein Precursors
  • Protein Synthesis Inhibitors
  • Pyridines
  • RNA, Messenger
  • Sulfonamides
  • Transcription Factor AP-1
  • proenkephalin
  • KN 62
  • 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
  • Cycloheximide
  • Mitogen-Activated Protein Kinases
  • calphostin C
  • N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide
  • Sphingosine
  • SB 203580
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one