Neonatal asphyxia induces the nitration of cardiac myosin light chain 2 that is associated with cardiac systolic dysfunction.
Hypoxia followed by reoxygenation (H-R) observed during perinatal asphyxia is a serious complication with high mortality and morbidity rates that may cause adverse cardiovascular effects in neonates. Our aim was to determine if oxidative stress related to H-R induces peroxynitrite-dependent modifications of the cardiac contractile protein, myosin regulatory light chain 2 (MLC2), and whether this is associated with development of cardiac systolic dysfunction. Twelve newborn piglets were acutely instrumented for hemodynamic monitoring and randomized to a control group ventilated with only atmospheric air or to the H-R study group exposed to alveolar normocapnic hypoxia followed by reoxygenation. Afterward, animals were euthanized, and the hearts were harvested for biochemical analyses. Systolic function as well as cardiac MLC2 levels decreased in H-R animals, whereas nitrates and nitrotyrosine levels increased. Negative correlations between nitrates, nitrotyrosine, and MLC2 levels were observed. Moreover, H-R induced nitration of two tyrosine residues within the MLC2 protein. Similarly, in vitro exposure of MLC2 to peroxynitrite resulted in the nitration of tyrosine, which increased the susceptibility of MLC2 to subsequent degradation by matrix metalloproteinase 2. Substitution of this tyrosine with phenylalanine prevented the matrix metalloproteinase 2-dependent degradation of MLC2. In addition, a large decrease in MLC2 phosphorylation caused by H-R was observed. Oxidative stress related to asphyxia induces nitration of cardiac MLC2 protein and thus increases its degradation. This and a large decrease in MLC2 phosphorylation contribute to the development of systolic dysfunction. Inhibition of MLC2 nitration and/or direct inhibition of its degradation by MMP-2 could be potential therapeutic targets aiming at reduction of myocardial damage during resuscitation of asphyxiated newborns.
Doroszko
Adrian
A
Department of Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Polewicz
Dorota
D
Cadete
Virgilio J J
VJ
Sawicka
Jolanta
J
Jones
Michelle
M
Szczesna-Cordary
Danuta
D
Cheung
Po-Yin
PY
Sawicki
Grzegorz
G
D000818:Animals; D000831:Animals, Newborn; D001238:Asphyxia Neonatorum / Q000378:metabolism*; D015153:Blotting, Western; D024722:Cardiac Myosins / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D006333:Heart Failure / Q000378:metabolism; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D047468:Immunoprecipitation; D007231:Infant, Newborn; D018994:Myosin Light Chains / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D013552:Swine; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D018994:Myosin Light Chains; D009566:Nitrates; D009573:Nitrites; C107184:myosin light chain 2; C002744:3-nitrotyrosine; D014443:Tyrosine; D024722:Cardiac Myosins
Heart Fail Rev. 2002 Oct;7(4):359-69
12379821
J Appl Physiol (1985). 1989 Dec;67(6):2447-53
2606853
Lancet. 2005 Mar 5-11;365(9462):891-900
15752534
Basic Res Cardiol. 2009 Nov;104(6):669-79
19452190
Heart Fail Rev. 2005 Sep;10(3):187-97
16416042
Anal Biochem. 1982 Oct;126(1):131-8
7181105
J Mol Cell Cardiol. 1997 Oct;29(10):2641-52
9344759
Br J Pharmacol. 2003 Feb;138(4):532-43
12598407
Recent Adv Stud Cardiac Struct Metab. 1976 May 26-29;11:111-20
145626
Shock. 2008 Jan;29(1):65-70
17666953
Circ Res. 1999 Sep 3;85(5):446-56
10473674
Pharmacol Res. 2004 Jan;49(1):7-16
14597146
J Mol Cell Cardiol. 2009 Jan;46(1):108-15
18929571
Circulation. 2002 Sep 17;106(12):1543-9
12234962
Biomed Chromatogr. 2007 Mar;21(3):273-8
17236239
Curr Drug Targets Cardiovasc Haematol Disord. 2003 Jun;3(2):187-97
12769642
Am J Physiol Heart Circ Physiol. 2005 Jan;288(1):H371-81
15345482
Circulation. 2005 Jul 26;112(4):544-52
16027249
Anal Biochem. 1997 Sep 5;251(2):187-95
9299015
Science. 1993 Jul 2;261(5117):50-8
8316857
Cardiovasc Res. 2006 May 1;70(2):181-90
16580655
J Mol Cell Cardiol. 2003 Jul;35(7):833-40
12818574
Cochrane Database Syst Rev. 2007 Jan 24;(1):CD005090
17253539
FASEB J. 2009 Oct;23(10):3571-80
19470801
Basic Res Cardiol. 1992;87 Suppl 1:129-41
1386730
Am J Physiol Heart Circ Physiol. 2007 Apr;292(4):H1643-54
17142342
J Mol Cell Cardiol. 2002 Apr;34(4):401-11
11991730
J Mol Med (Berl). 1999 Jul;77(7):544-55
10494800
Shock. 2007 Sep;28(3):317-25
17545944
Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):4462-4
8633090
Arch Dis Child Fetal Neonatal Ed. 2004 Mar;89(2):F152-5
14977901
Shock. 2005 Apr;23(4):383-9
15803064
Lancet. 2009 May 9;373(9675):1581-2
19386356
Heart Fail Rev. 2002 Oct;7(4):391-405
12379824
J Mol Cell Cardiol. 1988 Oct;20(10):875-86
2975339
Acta Physiol Scand. 1995 Jul;154(3):343-53
7572232
Biochem J. 1986 Nov 15;240(1):205-14
3827840