Increased longevity and refractoriness to Ca(2+)-dependent neurodegeneration in Surf1 knockout mice

Hum Mol Genet. 2007 Feb 15;16(4):431-44. doi: 10.1093/hmg/ddl477. Epub 2007 Jan 8.

Abstract

Leigh syndrome associated with cytochrome c oxidase (COX) deficiency is a mitochondrial disorder usually caused by mutations of SURF1, a gene encoding a putative COX assembly factor. We present here a Surf1-/- recombinant mouse obtained by inserting a loxP sequence in the open reading frame of the gene. The frequency of -/-, +/+ and +/- genotypes in newborn mice followed a mendelian distribution, indicating that the ablation of Surf1 is compatible with postnatal survival. The biochemical and assembly COX defect was present in Surf1(loxP)-/- mice, but milder than in humans. Surprisingly, not only these animals failed to show spontaneous neurodegeneration at any age, but they also displayed markedly prolonged lifespan, and complete protection from Ca(2+)-dependent neurotoxicity induced by kainic acid. Experiments on primary neuronal cultures showed markedly reduced rise of cytosolic and mitochondrial Ca(2+) in Surf1(loxP)-/- neurons, and reduced mortality, compared to controls. The mitochondrial membrane potential was unchanged in KO versus wild-type neurons, suggesting that the effects of the ablation of Surf1 on Ca(2+) homeostasis, and possibly on longevity, may be independent, at least in part, from those on COX assembly and mitochondrial bioenergetics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Calcium / metabolism
  • Calcium / physiology*
  • Calcium Signaling / drug effects
  • Cells, Cultured
  • Female
  • Glutamic Acid / pharmacology
  • Kainic Acid
  • Longevity / genetics*
  • Male
  • Membrane Potential, Mitochondrial / genetics
  • Membrane Proteins / genetics*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred DBA
  • Mice, Knockout
  • Mitochondrial Proteins / genetics*
  • Neurodegenerative Diseases / chemically induced*
  • Neurodegenerative Diseases / genetics
  • Phenotype

Substances

  • Membrane Proteins
  • Mitochondrial Proteins
  • Surf-1 protein
  • Glutamic Acid
  • Kainic Acid
  • Calcium