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Enhanced Generation of Mitochondrial Reactive Oxygen Species in Cybrids Containing 4977‐bp Mitochondrial DNA Deletion
Author(s) -
JOU MEIJIE,
PENG TSUNGI,
WU HONGYUEH,
WEI YAUHUEI
Publication year - 2005
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1338.024
Subject(s) - mitochondrial dna , reactive oxygen species , oxidative stress , mitochondrion , bioenergetics , mitochondrial ros , biology , oxidative phosphorylation , microbiology and biotechnology , chemistry , genetics , biochemistry , gene
A bstract : The poor bioenergetic state in mitochondria containing mtDNA with the 4977‐bp deletion has been well documented. However, information on mitochondrial reactive oxygen species (ROS) generation at rest or under intense oxidative stress in mitochondria lacking the 4977‐bp mtDNA fragment inside intact living cells was insufficient. We used cybrids containing truncated mtDNA lacking the 4977‐bp fragment and measured ROS levels inside cybrids by fluorescence probe, 2′,7′‐dichlorodihydrofluorescein (DCF), and confocal microscopy. Mitochondrial ROS at resting state was slightly higher in cybrids containing 4977‐bp deletion mtDNA as compared to cybrids without mtDNA defects. For intense oxidative stress treatment, cybrids were treated with 5 mM H 2 O 2 for 10 min. Consecutive DCF images were acquired after H 2 O 2 had been washed away. Progressive increase of DCF signals, especially in the mitochondrial area, was observed in cybrids containing 4977‐bp deletion mtDNA, even long after the brief, intense H 2 O 2 treatment. This result suggests that a feed‐forward, self‐accelerating vicious cycle of mitochondrial ROS production could be initiated in cybrids containing 4977‐bp deletion fragment mitochondria after brief, intense H 2 O 2 treatment. This mechanism may play an important role in the pathophysiology of the disease process caused by mitochondria containing mtDNA with the 4977‐bp deletion.