Hypoxia-induced neuronal apoptosis is mediated by de novo synthesis of ceramide through activation of serine palmitoyltransferase.

Cellular hypoxia can lead to cell death or adaptation and has important effects on development, physiology, and pathology. Here, we investigated the role and regulation of ceramide in hypoxia-induced apoptosis of SH-SY5Y neuroblastoma cells. Hypoxia increased the ceramide concentration; subsequently, we observed biochemical changes indicative of apoptosis, such as DNA fragmentation, nuclear staining, and poly ADP-ribose polymerase (PARP) cleavage. The hypoxic cell death was potently inhibited by a caspase inhibitor, zVAD-fmk (benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone). l-Cycloserine, a serine palmitoyltransferase (SPT) inhibitor, and fumonisin B(1) (FB(1)), a ceramide synthase inhibitor, inhibited the hypoxia-induced increase in ceramide, indicating that the increase occurred via the de novo pathway. Hypoxia increased the activity and protein levels of SPT2, suggesting that the hypoxia-induced increase in ceramide is due to the transcriptional up-regulation of SPT2. Specific siRNA of SPT2 prevented hypoxia-induced cell death and ceramide production. However, hypoxia also increased the cellular level of glucosylceramide, which was inhibited by a glucosylceramide synthase (GCS) inhibitor and specific siRNA, but not a ceramidase inhibitor. The increase in glucosylceramide was accompanied by increases in both PARP cleavage and DNA fragmentation. Together, the current results suggest that both SPT and GCS may regulate the cellular level of ceramide, and thus may be critical enzymes for deciding the fate of the cells exposed to hypoxia.
AuthorsMi Sun Kang, Kyong Hoon Ahn, Seok Kyun Kim, Hyung Jun Jeon, Jung Eun Ji, Jong Min Choi, Kwang Mook Jung, Sung Yun Jung, Dae Kyong Kim
JournalCellular signalling (Cell Signal) Vol. 22 Issue 4 Pg. 610-8 (Apr 2010) ISSN: 1873-3913 [Electronic] England
PMID19932170 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
CopyrightCopyright 2009 Elsevier Inc. All rights reserved.
Chemical References
  • Ceramides
  • Endocannabinoids
  • Enzyme Inhibitors
  • Ethanolamines
  • Glucosylceramides
  • Morpholines
  • Oleic Acids
  • N-oleoylethanolamine
  • RV 538
  • Serine C-Palmitoyltransferase
  • Glucosyltransferases
  • ceramide glucosyltransferase
  • Sphingosine
  • Apoptosis
  • Cell Hypoxia
  • Cell Line, Tumor
  • Ceramides (metabolism)
  • Endocannabinoids
  • Enzyme Inhibitors (pharmacology)
  • Ethanolamines (pharmacology)
  • Glucosylceramides (metabolism)
  • Glucosyltransferases (metabolism)
  • Humans
  • Morpholines (pharmacology)
  • Neurons (cytology, metabolism)
  • Oleic Acids
  • Serine C-Palmitoyltransferase (metabolism)
  • Sphingosine (metabolism)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research network!

Choose Username:
Verify Password: