Hypercontractile female hearts exhibit increased S-nitrosylation of the L-type Ca2+ channel alpha1 subunit and reduced ischemia/reperfusion injury.
Mechanisms underlying gender differences in cardiovascular disease are poorly understood. We found previously that, under hypercontractile conditions, female hearts exhibit significantly less ischemia/reperfusion injury than males. Here we show that male wild-type (WT) mouse hearts pretreated with 10 nmol/L isoproterenol before ischemia exhibited increased injury versus female hearts, but this relative protection in females was absent in eNOS(-/-) and nNOS(-/-) hearts. In isoproterenol-treated female versus male hearts, there was also more endothelial NO synthase (eNOS) associated with cardiomyocyte caveolin-3, and more neuronal NOS (nNOS) translocation to caveolin-3 during ischemia/reperfusion. S-nitrosothiol (SNO) formation was increased in isoproterenol-treated ischemic/reperfused hearts in all mouse genotypes, but only in WT mice was SNO content significantly higher in females than males. Using the biotin switch method, we identified the L-type Ca2+ channel alpha1 subunit as the predominant S-nitrosylated protein in membrane fractions, and following isoproterenol and ischemia/reperfusion male/female differences in SNO were seen only in WT hearts, but not in constitutive NOS(-/-) genotypes. The isoproterenol-induced increase in L-type Ca2+ current (ICa) was smaller in females versus in males, but NOS blockade increased ICa in females. This gender difference in ICa in isoproterenol-treated myocytes (and abolition on NOS inhibition) was mirrored exactly in Ca2+ transients and SR Ca2+ contents. In conclusion, these data suggest that eNOS and nNOS both play roles in the gender differences observed in ischemia/reperfusion injury under adrenergic stimulation, and also demonstrate increased S-nitrosylation of the L-type Ca2+ channels in female cardiomyocytes.
Sun
Junhui
J
National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
Picht
Eckard
E
Ginsburg
Kenneth S
KS
Bers
Donald M
DM
Steenbergen
Charles
C
Murphy
Elizabeth
E
D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002316:Cardiotonic Agents / Q000494:pharmacology; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D052248:Nitric Oxide Synthase Type I / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D012727:Sex Characteristics
D020746:Calcium Channels, L-Type; D002316:Cardiotonic Agents; C419385:L-type calcium channel alpha(1C); D052248:Nitric Oxide Synthase Type I; D052250:Nitric Oxide Synthase Type III; D007545:Isoproterenol