MITOCHIP assessment of differential gene expression in the skeletal muscle of Ant1 knockout mice: coordinate regulation of OXPHOS, antioxidant, and apoptotic genes.
Genetic inactivation of the nuclear-encoded mitochondrial heart-muscle adenine nucleotide translocator-1 (ANT1), which exports mitochondrial ATP to the cytosol in both humans (ANT1-/-) and mice (Ant1-/-), results in lactic acidosis and mitochondrial cardiomyopathy and myopathy, the latter involving hyper-proliferation of mitochondria, induction of oxidative phosphorylation (OXPHOS) enzymes, increased reactive oxygen species (ROS), and excessive mtDNA damage. To understand these manifestations, we analyzed Ant1-/- mouse skeletal muscle for changes in gene expression using our custom 644 and 1087 gene MITOCHIP microarrays and for changes in the protein levels of key mitochondrial transcription factors. Thirty-four mRNAs were found to be up-regulated and 29 mRNAs were down-regulated. Up-regulated mRNAs included the mitochondrial DNA (mtDNA) polypeptide and rRNA genes, selected nuclear-encoded OXPHOS genes, and stress-response genes including Mcl-1. Down-regulated mRNAs included glycolytic genes, pro-apoptotic genes, and c-Myc. The mitochondrial regulatory proteins Pgc-1alpha, Nrf-1, Tfam, and myogenin were up-regulated and could account for the induction of the OXPHOS and antioxidant enzymes. By contrast, c-Myc levels were reduced and might account for a reduction in apoptotic potential. Therefore, the Ant1-/- mouse skeletal muscle demonstrates that energy metabolism, antioxidant defenses, and apoptosis form an integrated metabolic network.
Subramaniam
Vaidya
V
Center of Molecular and Mitochondrial Medicine and Genetics (MAMMAG) and Department of Biological Chemistry, University of California Irvine, 2010 Hewitt Hall, Irvine, CA 92697, USA.
Golik
Pawel
P
Murdock
Deborah G
DG
Levy
Shawn
S
Kerstann
Keith W
KW
Coskun
Pinar E
PE
Melkonian
Goarik A
GA
Wallace
Douglas C
DC
D033741:Adenine Nucleotide Translocator 1 / Q000172:deficiency* / Q000235:genetics*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000235:genetics*; D003001:Cloning, Molecular; D004734:Energy Metabolism; D051379:Mice; D018345:Mice, Knockout; D020411:Oligonucleotide Array Sequence Analysis; D010085:Oxidative Phosphorylation; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D015854:Up-Regulation
D033741:Adenine Nucleotide Translocator 1; D000975:Antioxidants; D011994:Recombinant Proteins; D012313:RNA