Sphingosine kinase 1/S1P pathway involvement in the GDNF-induced GAP43 transcription.

Abstract

Glial cell line-derived neurotrophic factor (GDNF) is important for the development and maintenance of dopamine neurons (Lin et al. [1993] Science 260: 1130-1132). GDNF is neuroprotective in animal models of Parkinson disease, where dopamine neurons show selective degeneration. We previously reported GDNF-induced SPHK1 gene expression in a neuroblastoma cell line, TGW (Murakami et al. [2007] J Neurochem 102: 1585-1594). In the present study, we focused on the regulatory mechanism of GAP43 (GDNF-induced neuronal phenotype) transcription to further elucidate physiological roles of GDNF-induced SPHK1 expression and activity. Stable wild-type (SPHK1-WT) but not dominant-negative SPHK1 (SPHK1-DN) overexpression increased both control- and GDNF-induced GAP43 expression. SPHK1-WT cells showed enhanced GDNF-induced sphingosine 1-phosphate (S1P) secretion compared with mock- and SPHK1-DN cells. Exogenous S1P also increased GAP43 expression. In TGW cells, PD98059, a MEK inhibitor, but not SB203580 (a p38 MAPK inhibitor) and LY294002 (a PI3K inhibitor) inhibited GDNF-induced GAP43 expression, suggesting the MEK/ERK pathway has a major role in GDNF-induced GAP43 transcription. A G-protein-coupled receptor inhibitor, pertussis toxin, and S1P(1) and S1P(3) receptor antagonists (VPC23019 and CAY10444) also inhibited ERK activation. Moreover, both S1P1 and S1P3 were serine-phosphorylated by GDNF, suggesting their activated states. C/EBPβ transcription factor was induced by GDNF, and DNA pull-down and chromatin immunoprecipitation assays revealed the C/EBP binding site between -131 bp and -98  bp from the first exon of GAP43. Taken together, our results showed that in TGW cells, GDNF increased SPHK1 transcription, leading to the production and secretion of S1P. Through MEK/ERK pathway, S1P stimulates GAP43 transcription with increased binding of C/EBPβ to the 5'-promoter.

• Authors: Masashi Murakami, Hiromi Ito, Kazumi Hagiwara, Misa Kobayashi, Asuka Hoshikawa, Akira Takagi, Tetsuhito Kojima, Keiko Tamiya-Koizumi, Sayaka Sobue, Masatoshi Ichihara, Motoshi Suzuki, Yoshiko Banno, Yoshinori Nozawa, Takashi Murate
• Journal: Journal of cellular biochemistry (J Cell Biochem) Vol. 112 Issue 11 Pg. 3449-58 (Nov 2011) ISSN: 1097-4644 [Electronic] United States
• PMID: 21769916 (Publication Type: Journal Article)
• Copyright: Copyright © 2011 Wiley Periodicals, Inc.

Chemical References

• DNA Primers
• GAP-43 Protein
• Glial Cell Line-Derived Neurotrophic Factor
• Lysophospholipids
• sphingosine 1-phosphate
• Phosphotransferases (Alcohol Group Acceptor)
• sphingosine kinase
• Sphingosine

Topics

• Base Sequence
• Blotting, Western
• Cell Line, Tumor
• Chromatin Immunoprecipitation
• Cloning, Molecular
• DNA Primers
• GAP-43 Protein (genetics)
• Glial Cell Line-Derived Neurotrophic Factor (metabolism)
• Humans
• Lysophospholipids (metabolism)
• Phosphotransferases (Alcohol Group Acceptor) (metabolism)
• Polymerase Chain Reaction
• Promoter Regions, Genetic
• Signal Transduction
• Sphingosine (analogs & derivatives, metabolism)
• Transcription, Genetic