C/EBP-delta induction by gp130 signaling. Role in transition to myelin gene expressing phenotype in a melanoma cell line model.
Expression of genes encoding structural myelin proteins marks the inception of the myelinating Schwann cell (SC) phenotype. Earlier embryonic SC as well as adult non-myelinating SC produce the intermediate filament glial fibrillary acid protein (GFAP), which disappears from the myelinating SC. We previously observed that triggering of the gp130 receptor system by the IL6RIL6 ligand, comprising interleukin-6 (IL-6) fused to the soluble IL-6 receptor, induces myelin gene expression in rat embryonic dorsal root ganglia (DRG) cultures as well as in the murine melanoma cell line B16/F10.9. Study of target genes regulated by IL6RIL6 indicates a strong and selective induction of the transcriptional regulator C/EBP-delta in DRG cultures and in the F10.9 cell line. As shown here, silencing of C/EBP-delta mRNA and protein expression by introduction of small interference RNA-producing plasmids in the F10.9 cells prevented the induction of myelin protein zero (P0) and myelin basic protein (MBP) mRNAs by IL6RIL6. Doxycycline-regulated overexpression of C/EBP-delta was sufficient to induce accumulation of P0 and MBP mRNAs, the effect being selective, because C/EBP-delta did not affect several other genes strongly regulated by IL6RIL6. Interestingly, GFAP was inhibited by C/EBP-delta overexpression, leading to a modulation of the ratio between myelin gene products versus GFAP and suggesting that C/EBP-delta plays a role in the switch to a myelinating phenotype. The down-regulation of Pax3, also typical of the transition to myelinating cells, was observed after C/EBP-delta expression in correlation to P0 induction and to decrease of melanogenesis and cell growth. In cultures of dissociated cells of embryonic rat DRG, where we knocked-down the C/EBP-delta mRNA, we found an inhibition of P0 mRNA induction by IL6RIL6, showing that the role of C/EBP-delta on this myelin gene is not unique to the melanoma system.
Kamaraju
Anil K
AK
Department of Molecular Genetics, Weizmann Institute of Science, Rehov Herzl, Rehovot 76100, Israel.
Adjalley
Sophie
S
Zhang
Peilin
P
Chebath
Judith
J
Revel
Michel
M
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015703:Antigens, CD / Q000378:metabolism*; D015153:Blotting, Western; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins / Q000502:physiology*; D002455:Cell Division; D045744:Cell Line, Tumor; D050822:Cytokine Receptor gp130; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004318:Doxycycline / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008024:Ligands; D008545:Melanoma / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor; D009186:Myelin Sheath / Q000378:metabolism*; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D010641:Phenotype; D011485:Protein Binding; D018075:RNA, Complementary / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013752:Tetracycline / Q000494:pharmacology; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection
D000900:Anti-Bacterial Agents; D015703:Antigens, CD; D022762:CCAAT-Enhancer-Binding Proteins; C497253:Cebpd protein, mouse; C497254:Cebpd protein, rat; D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; C494200:Il6st protein, mouse; C494201:Il6st protein, rat; D015850:Interleukin-6; D008024:Ligands; D008562:Membrane Glycoproteins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; C497236:Mitf protein, rat; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D018075:RNA, Complementary; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; D050822:Cytokine Receptor gp130; C068686:Pax3 protein, mouse; D051743:CCAAT-Enhancer-Binding Protein-delta; D004247:DNA; D013752:Tetracycline; D004318:Doxycycline