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Targeted overexpression of α‐8‐oxoguanine DNA glycosylase in mitochondria (mt‐Ogg1) decreases cell death in response to oxidant stress or ischemia‐reperfusion injury.
Author(s) -
Kondapalli Jyothisri,
Loor Gabriel,
Schumacker Paul
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1377
Subject(s) - dna glycosylase , cell injury , mitochondrion , mitochondrial dna , reperfusion injury , programmed cell death , ischemia , oxidative stress , chemistry , dna damage , microbiology and biotechnology , apoptosis , dna , medicine , gene , biology , biochemistry , cardiology
Ischemia‐reperfusion (I/R) induces cell death through a mechanism involving increased oxidant stress and mitochondrial depolarization, but the molecular targets of oxidant damage responsible for triggering cell death are unknown. ROS are generated in mitochondria during I/R and, given the ability of nuclear DNA damage to trigger p53‐dependent cell death, we hypothesized that oxidative damage to mitochondrial DNA (mtDNA) might contribute to cell death in I/R. Oxidant damage to DNA results in 8‐hydroxyguanine (8‐OHG) formation, and the DNA repair enzyme (‐8‐oxoguanine DNA glycosylase/apurinic lyase excises 8‐OHG. A mitochondrial targeting sequence was appended to human (‐ogg1 (mt‐ogg1), and murine embryonic fibroblasts were transfected with that construct and challenged with xanthine/xanthine oxidase. Mitochondrial localization of mt‐ogg1 was confirmed by immunocytochemistry. Quantitative Southern analysis revealed that mt‐ogg1 expression suppressed the resulting mt‐DNA damage and decreased cell death. Chick cardiomyocytes expressing adenovirus mediated mt‐ogg1 were subjected to simulated I/R in flow‐through chamber. mt‐Ogg1 expressing cells demonstrated a significant decrease in cell death, compared with empty vector‐infected controls. Thus, the accumulation of 8‐OHG in mtDNA appears to be involved in the regulation of cell death of cardiomyocytes subjected I/R. These findings suggest that mtDNA may act as a sentinel molecule in the regulation of cell survival in cardiac I/R injury. Supported by HL35440 and HL079650.