Loss of neutral ceramidase protects cells from nutrient- and energy -deprivation-induced cell death

Kumaran Sundaram, Andrew R. Mather, Subathra Marimuthu, Parag P. Shah, Ashley J. Snider, Lina M. Obeid, Yusuf A. Hannun, Levi J. Beverl, Leah J. Siskind

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Sphingolipids are a family of lipids that regulate the cell cycle, differentiation and cell death. Sphingolipids are known to play a role in the induction of apoptosis, but a role for these lipids in necroptosis is largely unknown. Necroptosis is a programmed form of cell death that, unlike apoptosis, does not require ATP. Necroptosis can be induced under a variety of conditions, including nutrient deprivation and plays a major role in ischaemia/reperfusion injury to organs. Sphingolipids play a role in ischaemia/reperfusion injury in several organs. Thus, we hypothesized that sphingolipids mediate nutrient-deprivation-induced necroptosis. To address this, we utilized mouse embryonic fibroblast (MEFs) treated with 2-deoxyglucose (2DG) and antimycin A (AA) to inhibit glycolysis and mitochondrial electron transport. 2DG/AA treatment of MEFs induced necroptosis as it was receptor- interacting protein (RIP)-1/3 kinase-dependent and caspase-independent. Ceramides, sphingosine (Sph) and sphingosine 1-phosphate (S1P) were increased following 2DG/AA treatment. Cells >lacking neutral ceramidase (nCDase- -/- ) were protected from 2DG/AA. Although nCDase- -/- cells generated ceramides following 2DG/AA treatment, they did not generate Sph or S1P. This protection was stimulus-independent as nCDase nCDase-/ - cells were also protected from endoplasmic reticulum (ER) stressors [tunicamycin (TN) or thapsigargin (TG)]. nCDase- -/- MEFs had higher autophagic flux and mitophagy than wild-type (WT) MEFs and inhibition of autophagy sensitized them to necroptosis. These data indicate that loss of nCDase protects cells from nutrientdeprivation-induced necroptosis via autophagy, and clearance of damaged mitochondria. Results suggest that nCDase is a mediator of necroptosis and might be a novel therapeutic target for protection from ischaemic injury.

Original languageEnglish (US)
Pages (from-to)743-755
Number of pages13
JournalBiochemical Journal
Volume473
Issue number6
DOIs
StatePublished - Mar 15 2016
Externally publishedYes

Keywords

  • Autophagy flux
  • Endoplasmic reticulum (er) stress
  • Mitophagy
  • Necroptosis
  • Neutral ceramidase
  • Sphingolipids.

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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