Overexpression of a calpastatin transgene in mdx muscle reduces dystrophic pathology
Overexpression of a calpastatin transgene in mdx muscle reduces dystrophic pathology
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DOI：
10.1093/hmg/11.21.2645
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发表时间：
2002-10-01
影响因子：
3.5
通讯作者：
Mellgren, RL
中科院分区：
文献类型：
--
作者：
Spencer, MJ;Mellgren, RL
据报道，mdx小鼠和杜氏肌营养不良症（DMD）患者的肌营养不良蛋白缺陷型肌肉中肌膜完整性降低会导致钙稳态改变。以前的研究表明，钙依赖性蛋白酶（钙蛋白酶）的活性在营养不良的肌肉和肌肉坏死之间的相关关系，但还没有测试是否钙蛋白酶激活之前的细胞死亡或它的后果。为了测试钙蛋白酶激活和肌细胞死亡之间的因果关系，肌营养不良蛋白缺乏症，mdx小鼠产生过表达钙蛋白酶抑制蛋白转基因的肌肉。钙蛋白酶抑制素（CS）是一种特异性的、内源性的m-和mu-钙蛋白酶抑制剂，其不抑制钙蛋白酶3（p94）。在C57/BL 10背景下CS过表达不产生表型。测试与mdx小鼠杂交的转基因（Tg）小鼠的坏死、再生和膜损伤的病理学指标。检查了具有不同CS过表达水平的两个品系的小鼠。两种品系的Tg/mdx小鼠在4周龄时均显示肌肉坏死减少。这些小鼠的病变较少且较小。此外，一组小鼠的再生明显较少，表明先前的坏死减少。改善程度与CS蛋白表达水平相关。通过普罗西翁橙子和肌酸激酶测定评估的膜损伤没有变化，支持钙蛋白酶在原发性肌肉缺陷下游起作用的观点。这些数据表明，钙蛋白酶在营养不良肌肉的坏死过程中起着积极的作用，抑制钙蛋白酶可能为治疗DMD提供一个很好的治疗选择。
Reduced sarcolemmal integrity in dystrophin-deficient muscles of mdx mice and Duchenne muscular dystrophy (DMD) patients has been reported to result in altered calcium homeostasis. Previous studies have shown a correlative relationship between calcium-dependent protease (calpain) activity in dystrophic muscle and muscle necrosis, but have not tested whether calpain activation precedes cell death or is a consequence of it. To test a causal relationship between calpain activation and muscle cell death in dystrophin deficiency, mdx mice were generated that overexpress a calpastatin transgene in muscle. Calpastatin (CS) is a specific, endogenous inhibitor of m- and mu-calpains that does not inhibit calpain 3 (p94). CS overexpression on a C57/BL 10 background produced no phenotype. Transgenic (Tg) mice crossed with mdx mice were tested for pathological indicators of necrosis, regeneration and membrane damage. Two lines of mice were examined, with different levels of CS overexpression. Both lines of Tg/mdx mice showed reductions in muscle necrosis at 4 weeks of age. These mice had fewer as well as smaller lesions. In addition, one line of mice had significantly less regeneration, indicating a reduction in previous necrosis. The extent of improvement correlated with the level of CS protein expression. Membrane damage, as assessed by procion orange and creatine kinase assays, was unchanged, supporting the idea that calpains act downstream of the primary muscle defect. These data suggest that calpains play an active role in necrotic processes in dystrophic muscle and that inhibition of calpains might provide a good therapeutic option for treatment of DMD.