UCP4 is a target effector of the NF-κB c-Rel prosurvival pathway against oxidative stress

Free Radic Biol Med. 2012 Jul 15;53(2):383-94. doi: 10.1016/j.freeradbiomed.2012.05.002. Epub 2012 May 8.

Abstract

Mitochondrial uncoupling protein-4 (UCP4) enhances neuronal survival in 1-methyl-4-phenylpyridinium (MPP(+)) toxicity by suppressing oxidative stress and preserving intracellular ATP and mitochondrial membrane potential (MMP). NF-κB regulates neuronal viability via its complexes, p65 mediating cell death and c-Rel promoting cell survival. We reported previously that NF-κB mediates UCP4 neuroprotection against MPP(+) toxicity. Here, we investigated its link with the NF-κB c-Rel prosurvival pathway in alleviating mitochondrial dysfunction and oxidative stress. We overexpressed a c-Rel-encoding plasmid in SH-SY5Y cells and showed that c-Rel overexpression induced NF-κB activity without affecting p65 level. Overexpression of c-Rel increased UCP4 promoter activity and protein expression. Electrophoretic mobility shift assay showed that H(2)O(2) increased NF-κB binding to the UCP4 promoter and that NF-κB complexes were composed of p50/p50 and p50/c-Rel dimers. Under H(2)O(2)-induced oxidative stress, UCP4 knockdown significantly increased superoxide levels, decreased reduced glutathione (GSH) levels, and increased oxidized glutathione levels, compared to controls. UCP4 expression induced by c-Rel overexpression significantly decreased superoxide levels and preserved GSH levels and MMP under similar stress. These protective effects of c-Rel overexpression in H(2)O(2)-induced oxidative stress were significantly reduced after UCP4 knockdown, indicating that UCP4 is a target effector gene of the NF-κB c-Rel prosurvival pathway to mitigate the effects of oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Electrophoretic Mobility Shift Assay
  • Gene Expression
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Membrane Transport Proteins / genetics*
  • Membrane Transport Proteins / metabolism
  • Mitochondria / genetics
  • Mitochondria / metabolism*
  • Mitochondrial Uncoupling Proteins
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Oxidative Stress
  • Promoter Regions, Genetic
  • Protein Binding
  • Proto-Oncogene Proteins c-rel
  • RNA, Small Interfering / genetics
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Signal Transduction
  • Superoxides / antagonists & inhibitors
  • Superoxides / metabolism
  • Transcription Factor RelA / genetics*
  • Transcription Factor RelA / metabolism

Substances

  • DNA-Binding Proteins
  • Membrane Transport Proteins
  • Mitochondrial Uncoupling Proteins
  • Nuclear Proteins
  • Proto-Oncogene Proteins c-rel
  • REL protein, human
  • RNA, Small Interfering
  • Recombinant Proteins
  • SLC25A27 protein, human
  • Transcription Factor RelA
  • Superoxides
  • Hydrogen Peroxide