Oxidative posttranslational modifications mediate decreased SERCA activity and myocyte dysfunction in Galphaq-overexpressing mice.
Oxidative posttranslational modifications mediate decreased SERCA activity and myocyte dysfunction in Galphaq-overexpressing mice.
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DOI：
10.1161/circresaha.110.217570
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发表时间：
2010-07-23
影响因子：
20.1
通讯作者：
Colucci WS
中科院分区：
文献类型：
--
作者：
Lancel S;Qin F;Lennon SL;Zhang J;Tong X;Mazzini MJ;Kang YJ;Siwik DA;Cohen RA;Colucci WS
肌细胞收缩功能障碍发生在与钙调节异常相关的病理性重塑中。具有心肌细胞特异性Gαq过表达的小鼠发生与心肌细胞收缩功能障碍和钙调节异常相关的进行性左心室（LV）衰竭。我们检验了Gαq小鼠心脏中的肌细胞收缩功能障碍是由活性氧（ROS）介导的假设，特别是损伤肌浆网Ca++-ATP酶（SERCA）功能的氧化翻译后修饰（OPTM）。新鲜分离的Gαq小鼠心室肌细胞具有显著的收缩功能和钙瞬变异常。在Gαq心肌中，SERCA蛋白的数量没有改变，但显示了氧化半胱氨酸修饰的证据，反映在生物素化碘乙酰胺标记减少，以及特异性不可逆氧化修饰的证据，包括半胱氨酸674的磺酰化和酪氨酸294/295的硝化。在Gαq心肌中，最大钙刺激的SERCA活性降低47%。将Gαq小鼠与心肌细胞特异性过氧化氢酶过表达的转基因小鼠杂交，a）减少了SERCA氧化半胱氨酸修饰，B）减少了SERCA半胱氨酸674磺酰化和酪氨酸294/295硝化，c）恢复了SERCA活性，d）改善了心肌细胞钙瞬变和收缩功能。在Gα q诱导的心肌病中，肌细胞收缩功能障碍至少部分由SERCA的一个或多个OPTM介导。蛋白质OPTM参与了心肌功能障碍的病理生理学，因此可能为治疗干预提供靶点。
Myocyte contractile dysfunction occurs in pathological remodeling in association with abnormalities in calcium regulation. Mice with cardiac myocyte-specific overexpression of Gαq develop progressive left ventricular (LV) failure associated with myocyte contractile dysfunction and calcium dysregulation. We tested the hypothesis that myocyte contractile dysfunction in the Gαq mouse heart is mediated by reactive oxygen species (ROS), and in particular, oxidative post-translational modifications (OPTM) that impair the function of sarcoplasmic reticulum Ca++-ATPase (SERCA). Freshly isolated ventricular myocytes from Gαq mice had marked abnormalities of myocyte contractile function and calcium transients. In Gαq myocardium, SERCA protein was not altered in quantity, but displayed evidence of oxidative cysteine modifications reflected by decreased biotinylated iodoacetamide labeling, and evidence of specific irreversible oxidative modifications consisting of sulfonylation at cysteine 674 and nitration at tyrosines 294/295. Maximal calcium-stimulated SERCA activity was decreased 47% in Gαq myocardium. Cross-breeding Gαq mice with transgenic mice that have cardiac myocyte-specific overexpression of catalase a) decreased SERCA oxidative cysteine modifications, b) decreased SERCA cysteine 674 sulfonylation and tyrosine 294/295 nitration, c) restored SERCA activity, and d) improved myocyte calcium transients and contractile function. In Gαq-induced cardiomyopathy, myocyte contractile dysfunction is mediated, at least in part, by one or more OPTM of SERCA. Protein OPTM contribute to the pathophysiology of myocardial dysfunction, and thus may provide a target for therapeutic intervention.