A systems approach for decoding mitochondrial retrograde signaling pathways

• Published in: Science signaling Vol. 6; no. 264; p. rs4
• Main Authors: Chae, Sehyun, Ahn, Byung Yong, Byun, Kyunghee, Cho, Young Min, Yu, Myeong-Hee, Lee, Bonghee, Hwang, Daehee, Park, Kyong Soo
• Format: Journal Article
• Language: English
• Published: United States 26-02-2013
• Subjects: Blotting, Western; Cell Nucleus - physiology; Gene Expression Profiling; Heat-Shock Proteins - metabolism; Humans; MAP Kinase Kinase 4 - metabolism; Mitochondrial Diseases - physiopathology; Oxidative Phosphorylation; Oxygen Consumption - physiology; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Point Mutation - genetics; Reactive Oxygen Species - metabolism; Real-Time Polymerase Chain Reaction; Retinoid X Receptor alpha - metabolism; RNA, Transfer, Leu - genetics; Signal Transduction - physiology; Systems Biology - methods; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 1937-9145
• DOI: 10.1126/scisignal.2003266

Mitochondrial dysfunctions activate retrograde signaling from mitochondria to the nucleus. To identify transcription factors and their associated pathways that underlie mitochondrial retrograde signaling, we performed gene expression profiling of the cells engineered to have varying amounts of mitochondrial DNA with an A3243G mutation (mt3243) in the leucine transfer RNA (tRNA(Leu)), which reduces the abundance of proteins involved in oxidative phosphorylation that are encoded by the mitochondrial genome. The cells with the mutation exhibited reduced mitochondrial function, including compromised oxidative phosphorylation, which would activate diverse mitochondrial retrograde signaling pathways. By analyzing the gene expression profiles in cells with the mutant tRNA(Leu) and the transcription factors that recognize the differentially regulated genes, we identified 72 transcription factors that were potentially involved in mitochondrial retrograde signaling. We experimentally validated that the mt3243 mutation induced a retrograde signaling pathway involving RXRA (retinoid X receptor α), reactive oxygen species, kinase JNK (c-JUN N-terminal kinase), and transcriptional coactivator PGC1α (peroxisome proliferator-activated receptor γ, coactivator 1 α). This RXR pathway contributed to the decrease in mRNA abundances of oxidative phosphorylation enzymes encoded in the nuclear genome, thereby aggravating the dysfunction in oxidative phosphorylation caused by the reduced abundance of mitochondria-encoded enzymes of oxidative phosphorylation. Thus, matching transcription factors to differentially regulated gene expression profiles was an effective approach to understand mitochondrial retrograde signaling pathways and their roles in mitochondrial dysfunction.