Knock-out of a mitochondrial sirtuin protects neurons from degeneration in Caenorhabditis elegans

PLoS Genet. 2017 Aug 18;13(8):e1006965. doi: 10.1371/journal.pgen.1006965. eCollection 2017 Aug.

Abstract

Sirtuins are NAD⁺-dependent deacetylases, lipoamidases, and ADP-ribosyltransferases that link cellular metabolism to multiple intracellular pathways that influence processes as diverse as cell survival, longevity, and cancer growth. Sirtuins influence the extent of neuronal death in stroke. However, different sirtuins appear to have opposite roles in neuronal protection. In Caenorhabditis elegans, we found that knock-out of mitochondrial sirtuin sir-2.3, homologous to mammalian SIRT4, is protective in both chemical ischemia and hyperactive channel induced necrosis. Furthermore, the protective effect of sir-2.3 knock-out is enhanced by block of glycolysis and eliminated by a null mutation in daf-16/FOXO transcription factor, supporting the involvement of the insulin/IGF pathway. However, data in Caenorhabditis elegans cell culture suggest that the effects of sir-2.3 knock-out act downstream of the DAF-2/IGF-1 receptor. Analysis of ROS in sir-2.3 knock-out reveals that ROS become elevated in this mutant under ischemic conditions in dietary deprivation (DD), but to a lesser extent than in wild type, suggesting more robust activation of a ROS scavenging system in this mutant in the absence of food. This work suggests a deleterious role of SIRT4 during ischemic processes in mammals that must be further investigated and reveals a novel pathway that can be targeted for the design of therapies aimed at protecting neurons from death in ischemic conditions.

MeSH terms

  • Animals
  • Azides / toxicity
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / genetics*
  • Cell Death / drug effects
  • Forkhead Transcription Factors / genetics*
  • Gene Knockout Techniques
  • Glycolysis / drug effects
  • Humans
  • Hydrolases / genetics*
  • Insulin / genetics
  • Ischemia / genetics*
  • Ischemia / pathology
  • Mitochondria / genetics
  • Mitochondria / pathology
  • Mitochondrial Proteins / genetics*
  • Necrosis / genetics
  • Necrosis / pathology
  • Reactive Oxygen Species / metabolism
  • Receptor, IGF Type 1 / genetics
  • Receptor, Insulin / genetics
  • Sensory Receptor Cells / drug effects
  • Sensory Receptor Cells / metabolism*
  • Sirtuins / genetics*

Substances

  • Azides
  • Caenorhabditis elegans Proteins
  • Forkhead Transcription Factors
  • Insulin
  • Mitochondrial Proteins
  • Reactive Oxygen Species
  • daf-16 protein, C elegans
  • DAF-2 protein, C elegans
  • Receptor, IGF Type 1
  • Receptor, Insulin
  • Hydrolases
  • sir-2.3 protein, C elegans
  • SIRT4 protein, human
  • Sirtuins