TY - JOUR
T1 - Overexpression of mitochondrial ferritin sensitizes cells to oxidative stress via an iron-mediated mechanism
AU - Lu, Zhongbing
AU - Nie, Guangjun
AU - Li, Yiye
AU - Soe-lin, Shan
AU - Tao, Yi
AU - Cao, Yuanlin
AU - Zhang, Zhiyong
AU - Liu, Nianqing
AU - Ponka, Prem
AU - Zhao, Baolu
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2009/8/1
Y1 - 2009/8/1
N2 - Mitochondrial ferritin (MtFt) is a newly identified H-ferritin-like protein expressed only in mitochondria. Previous studies have shown that its overexpression markedly affects intracellular iron homeostasis and rescues defects caused by frataxin deficiency. To assess how MtFt exerts its function under oxidative stress conditions, MtFt overexpressing cells were treated with tert-butyl-hydroperoxide (tBHP), and the effects of MtFt expression on cell survival and iron homeostasis were examined. We found that MtFt expression was associated with decreased mitochondrial metabolic activity and reduced glutathione levels as well as a concomitant increase in reactive oxygen species levels and apoptosis. Moreover, mechanistic studies demonstrated that tBHP treatment led to a prolonged decrease in cytosolic ferritins levels in MtFt-expressing cells, while ferritin levels recovered to basal levels in control counterparts. tBHP treatment also resulted in elevated transferrin receptors, followed by more iron acquisition in MtFt expressing cells. The high molecular weight desferrioxamine, targeting to lysosomes, as well as the hydrophobic iron chelator salicylaldehyde isonicotinoyl hydrazone significantly attenuated tBHP-induced cell damage. In conclusion, the current study indicates that both the newly acquired iron from the extracellular environment and internal iron redistribution from ferritin degradation may be responsible for the increased sensitivity to oxidative stress in MtFt-expressing cells.
AB - Mitochondrial ferritin (MtFt) is a newly identified H-ferritin-like protein expressed only in mitochondria. Previous studies have shown that its overexpression markedly affects intracellular iron homeostasis and rescues defects caused by frataxin deficiency. To assess how MtFt exerts its function under oxidative stress conditions, MtFt overexpressing cells were treated with tert-butyl-hydroperoxide (tBHP), and the effects of MtFt expression on cell survival and iron homeostasis were examined. We found that MtFt expression was associated with decreased mitochondrial metabolic activity and reduced glutathione levels as well as a concomitant increase in reactive oxygen species levels and apoptosis. Moreover, mechanistic studies demonstrated that tBHP treatment led to a prolonged decrease in cytosolic ferritins levels in MtFt-expressing cells, while ferritin levels recovered to basal levels in control counterparts. tBHP treatment also resulted in elevated transferrin receptors, followed by more iron acquisition in MtFt expressing cells. The high molecular weight desferrioxamine, targeting to lysosomes, as well as the hydrophobic iron chelator salicylaldehyde isonicotinoyl hydrazone significantly attenuated tBHP-induced cell damage. In conclusion, the current study indicates that both the newly acquired iron from the extracellular environment and internal iron redistribution from ferritin degradation may be responsible for the increased sensitivity to oxidative stress in MtFt-expressing cells.
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U2 - 10.1089/ars.2008.2306
DO - 10.1089/ars.2008.2306
M3 - Article
C2 - 19271990
AN - SCOPUS:67650229951
SN - 1523-0864
VL - 11
SP - 1791
EP - 1803
JO - Antioxidants and Redox Signaling
JF - Antioxidants and Redox Signaling
IS - 8
ER -