title: Reactive oxygen species production in energized cardiac mitochondria during hypoxia/reoxygenation: modulation by nitric oxide.
abstract: Mitochondria are an important source of reactive oxygen species (ROS), implicated in ischemia/reperfusion injury. When isolated from ischemic myocardium, mitochondria demonstrate increased ROS production as a result of damage to electron transport complexes. To investigate the mechanisms, we studied effects of hypoxia/reoxygenation on ROS production by isolated energized heart mitochondria. ROS production, tracked using Fe(2+)-catalyzed, H(2)O(2)-dependent H(2)DCF oxidation or Amplex Red, was similar during normoxia and hypoxia but markedly increased during reoxygenation, in proportion to the duration of hypoxia. In contrast, if mitochondria were rapidly converted from normoxia to near-anoxia ([O(2)], <1 micromol/L), the increase in H(2)DCF oxidation rate during reoxygenation was markedly blunted. To elicit the robust increase in H(2)DCF oxidation rate during reoxygenation, hypoxia had to be severe enough to cause partial, but not complete, respiratory chain inhibition (as shown by partial dissipation of membrane potential and increased NADH autofluorescence). Consistent with its cardioprotective actions, nitric oxide ( O) abrogated increased H(2)DCF oxidation under these conditions, as well as attenuating ROS-induced increases in matrix [Fe(2+)] and aconitase inhibition caused by antimycin. Collectively, these results suggest that (1) hypoxia that is sufficient to cause partial respiratory inhibition is more damaging to mitochondria than near-anoxia; and (2) O suppresses ROS-induced damage to electron transport complexes, probably by forming O-Fe(2+) complexes in the presence of glutathione, which inhibit hydroxyl radical formation.
authors.affiliation: Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA. pkorge@mednet.ucla.edu
authors.forename: Paavo
authors.initials: P
authors.lastname: Korge
authors.forename: Peipei
authors.initials: P
authors.lastname: Ping
authors.forename: James N
authors.initials: JN
authors.lastname: Weiss
mesh_terms: D000154:Aconitate Hydratase / Q000378:metabolism; D000818:Animals; D015687:Cell Hypoxia; D019069:Cell Respiration; D004579:Electron Transport; D005452:Fluoresceins; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial; D008929:Mitochondria, Heart / Q000201:enzymology / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000517:prevention & control; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D005452:Fluoresceins; D017382:Reactive Oxygen Species; D009243:NAD; C065013:2',7'-dichlorodihydrofluorescein; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D007501:Iron; D000154:Aconitate Hydratase; D005978:Glutathione; D010100:Oxygen
references.citation: Am J Physiol Heart Circ Physiol. 2006 Nov;291(5):H2067-74
references.pmid: 16798828
references.citation: Trends Cell Biol. 2007 Feb;17(2):93-100
references.pmid: 17194590
references.citation: Proc Natl Acad Sci U S A. 2006 Oct 10;103(41):15038-43
references.pmid: 17015830
references.citation: J Biol Inorg Chem. 2005 Nov;10(7):732-8
references.pmid: 16208495
references.citation: J Mol Cell Cardiol. 2006 Jan;40(1):16-23
references.pmid: 16288777
references.citation: Am J Physiol Cell Physiol. 2001 Mar;280(3):C517-26
references.pmid: 11171571
references.citation: J Biol Chem. 2007 Jun 29;282(26):19133-43
references.pmid: 17488710
references.citation: J Biol Chem. 2007 Jan 12;282(2):929-37
references.pmid: 17102132
references.citation: Proc Natl Acad Sci U S A. 2005 Apr 26;102(17):5987-91
references.pmid: 15840721
references.citation: Biochem Biophys Res Commun. 2001 Mar 23;282(1):329-33
references.pmid: 11264011
references.citation: J Biol Chem. 1984 Mar 25;259(6):3620-4
references.pmid: 6323433
references.citation: Biochim Biophys Acta. 2008 Apr;1780(4):638-51
references.pmid: 18206118
references.citation: Anal Biochem. 2002 May 1;304(1):1-18
references.pmid: 11969183
references.citation: Am J Physiol Heart Circ Physiol. 2008 Aug;295(2):H874-82
references.pmid: 18586884
references.citation: Am J Physiol. 1996 Jun;270(6 Pt 1):L931-40
references.pmid: 8764217
references.citation: Cardiovasc Res. 2006 May 1;70(2):181-90
references.pmid: 16580655
references.citation: Biochem J. 1996 Mar 15;314 ( Pt 3):877-80
references.pmid: 8615783
references.citation: Circ Res. 2001 Aug 3;89(3):224-36
references.pmid: 11485972
references.citation: Cardiovasc Res. 2006 May 1;70(2):231-9
references.pmid: 16376869
references.citation: Int J Biochem Cell Biol. 2005 Dec;37(12):2478-503
references.pmid: 16103002
references.citation: Proc Natl Acad Sci U S A. 1993 Nov 1;90(21):9813-7
references.pmid: 8234317
references.citation: Respir Physiol. 2001 Nov 15;128(3):277-97
references.pmid: 11718759
references.citation: Biochemistry. 2003 Dec 23;42(50):14846-55
references.pmid: 14674759
references.citation: Am J Physiol Cell Physiol. 2008 Feb;294(2):C460-6
references.pmid: 18077608
references.citation: Free Radic Biol Med. 2008 Jan 1;44(1):56-62
references.pmid: 18045547
references.citation: J Mol Cell Cardiol. 2001 Jun;33(6):1065-89
references.pmid: 11444914
references.citation: Cardiovasc Res. 2008 Jan 15;77(2):344-52
references.pmid: 18006449
references.citation: Anal Biochem. 2003 Feb 1;313(1):46-52
references.pmid: 12576057
references.citation: J Mol Cell Cardiol. 2007 Apr;42(4):812-25
references.pmid: 17350035
references.citation: Biochem Biophys Res Commun. 2006 Jan 6;339(1):255-62
references.pmid: 16297871
references.citation: Circ Res. 2000 Mar 17;86(5):541-8
references.pmid: 10720416
references.citation: J Exp Med. 2007 Sep 3;204(9):2089-102
references.pmid: 17682069
references.citation: Free Radic Biol Med. 2007 Oct 1;43(7):995-1022
references.pmid: 17761297
references.citation: J Biol Chem. 1998 Jul 17;273(29):18092-8
references.pmid: 9660766
references.citation: Physiol Rev. 2003 Oct;83(4):1113-51
references.pmid: 14506302