In vivo administration of calpeptin attenuates calpain activation and cardiomyocyte loss in pressure-overloaded feline myocardium
In vivo administration of calpeptin attenuates calpain activation and cardiomyocyte loss in pressure-overloaded feline myocardium
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DOI：
10.1152/ajpheart.00085.2008
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发表时间：
2008-07-01
影响因子：
4.8
通讯作者：
Kuppuswamy, Dhandapani
中科院分区：
文献类型：
--
作者：
Mani, Santhosh K.;Shiraishi, Hirokazu;Kuppuswamy, Dhandapani
钙蛋白酶激活与几种细胞骨架蛋白的裂解有关，可能是心脏压力超负荷（PO）期间心肌细胞损失和收缩功能障碍的重要因素。使用猫右心室（RV）PO模型，我们分析了钙蛋白酶激活在早期代偿期的心脏肥大。钙蛋白酶富集及其活性增加，钙蛋白酶抑制蛋白水平降低，观察在24- 48小时PO心肌，这些变化恢复到基础水平的PO 1周。24小时PO心肌组织化学研究显示存在TdT介导的dUTP缺口末端标记（TUNEL）阳性心肌细胞，其表现出钙蛋白酶和凝溶胶蛋白的富集。生物化学研究显示组蛋白H2 B磷酸化和细胞骨架结合以及凝溶胶蛋白裂解的增加，这表明程序性心肌细胞死亡。为了测试钙蛋白酶抑制是否可以防止这些变化，我们给药钙蛋白酶（0.6毫克/公斤静脉注射）推注两次，15分钟前和6小时后诱导24小时PO。Calpeptin阻断PO诱导的以下变化：钙蛋白酶富集和激活，钙蛋白酶抑制蛋白水平降低，caspase-3激活，凝溶胶蛋白富集和切割，TUNEL染色和组蛋白H2 B磷酸化。虽然类似的半胱天冬酶抑制剂N-苯甲酰基羰基-Val-Ala-Asp-fluoromethylketone（Z-VD-fetamine）的给药阻断了半胱天冬酶-3活化，但它并没有减轻其他上述变化。这些结果表明，心肌细胞死亡的生化标志物，如肌节紊乱，凝溶胶蛋白裂解，和TUNEL阳性细胞核，介导的，至少部分，钙蛋白酶和钙蛋白酶可作为一种潜在的治疗剂，以防止心肌细胞损失和保护心肌结构和功能在心脏肥大。
Calpain activation is linked to the cleavage of several cytoskeletal proteins and could be an important contributor to the loss of cardiomyocytes and contractile dysfunction during cardiac pressure overload (PO). Using a feline right ventricular (RV) PO model, we analyzed calpain activation during the early compensatory period of cardiac hypertrophy. Calpain enrichment and its increased activity with a reduced calpastatin level were observed in 24- to 48-h-PO myocardium, and these changes returned to basal level by 1 wk of PO. Histochemical studies in 24-h-PO myocardium revealed the presence of TdT-mediated dUTP nick-end label (TUNEL)-positive cardiomyocytes, which exhibited enrichment of calpain and gelsolin. Biochemical studies showed an increase in histone H2B phosphorylation and cytoskeletal binding and cleavage of gelsolin, which indicate programmed cardiomyocyte cell death. To test whether calpain inhibition could prevent these changes, we administered calpeptin (0.6 mg/kg iv) by bolus injections twice, 15 min before and 6 h after induction of 24- h PO. Calpeptin blocked the following PO-induced changes: calpain enrichment and activation, decreased calpastatin level, caspase-3 activation, enrichment and cleavage of gelsolin, TUNEL staining, and histone H2B phosphorylation. Although similar administration of a caspase inhibitor, N-benzoylcarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VD-fmk), blocked caspase-3 activation, it did not alleviate other aforementioned changes. These results indicate that biochemical markers of cardiomyocyte cell death, such as sarcomeric disarray, gelsolin cleavage, and TUNEL-positive nuclei, are mediated, at least in part, by calpain and that calpeptin may serve as a potential therapeutic agent to prevent cardiomyocyte loss and preserve myocardial structure and function during cardiac hypertrophy.