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

• Published in: Free radical biology & medicine 2012-07, Vol.53 (2), p.383-394
• Main Authors: Wing-Man Ho, Jessica, Wing-Lok Ho, Philip, Liu, Hui-Fang, Hon-Fai So, Danny, Chan, Koon-Ho, Ho-Man Tse, Zero, Hiu-Wai Kung, Michelle, Boyer Ramsden, David, Ho, Shu-Leong
• Format: Article
• Language: English
• Subjects: adenosine triphosphate; c-Rel; cell death; Cell Line, Tumor; cell viability; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Electrophoretic Mobility Shift Assay; Free radicals; gel electrophoresis; Gene Expression; gene overexpression; genes; glutathione; Humans; hydrogen peroxide; Hydrogen Peroxide - pharmacology; membrane potential; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Mitochondria; Mitochondria - genetics; Mitochondria - metabolism; Mitochondrial dysfunction; mitochondrial membrane; Mitochondrial Uncoupling Proteins; neuroprotective effect; Nuclear factor-κB; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; oxidation; Oxidative Stress; Parkinson's disease; plasmids; Promoter Regions, Genetic; Protein Binding; protein synthesis; Proto-Oncogene Proteins c-rel; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; RNA, Small Interfering - genetics; Signal Transduction; Superoxides - antagonists & inhibitors; Superoxides - metabolism; toxicity; transcription factor NF-kappa B; Transcription Factor RelA - genetics; Transcription Factor RelA - metabolism; UCP; UCP4; Uncoupling protein
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2012.05.002

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 H2O2 increased NF-κB binding to the UCP4 promoter and that NF-κB complexes were composed of p50/p50 and p50/c-Rel dimers. Under H2O2-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 H2O2-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. ► We explored the link between c-Rel and uncoupling protein-4 (UCP4) in alleviating oxidative stress caused by H2O2. ► c-Rel overexpression induces NF-κB binding to the UCP4 promoter and UCP4 expression. ► c-Rel-induced UCP4 expression decreases O2− levels and preserves GSH levels and MMP. ► Protective effects of c-Rel overexpression are reduced after UCP4 knockdown. ► UCP4 is a target effector gene of the NF-κB c-Rel pathway to mitigate oxidative stress.