Calpain is activated in degenerating photoreceptors in the rd1 mouse
Calpain is activated in degenerating photoreceptors in the rd1 mouse
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DOI：
10.1111/j.1471-4159.2005.03628.x
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发表时间：
2006-02-01
影响因子：
4.7
通讯作者：
Ekström, P
中科院分区：
文献类型：
--
作者：
Paquet-Durand, F;Azadi, S;Ekström, P
视网膜变性（rd）1小鼠表现出遗传性视网膜变性，因此可以研究致盲性色素性视网膜炎背后的分子机制。钙依赖性蛋白酶calpain的激活已被认为在各种组织的细胞死亡中起重要作用，但对遗传性视网膜变性中calpain的表达和活性知之甚少。利用微阵列技术，分析了rd1小鼠与野生型对照相比，循环AMP反应元件结合蛋白(CREB)-1、钙pastatin和各种钙蛋白酶基因的转录水平。采用免疫荧光和免疫印迹法研究不同钙蛋白酶异构体和钙pastatin的表达。基因转录和蛋白表达水平与钙蛋白酶活性比较使用酶分析，允许在细胞水平上监测钙蛋白酶活性。我们发现CREB-1和calpastatin的表达在rd1视网膜中降低，而calpain的活性在rd1光感受器中显著增加。钙蛋白酶活性在出生后第13天达到峰值，同时rd1感光细胞死亡。calpain特异性抑制剂原位降低calpain活性。这些结果表明，钙蛋白酶的激活与rd1感光细胞死亡相关，这增加了使用钙蛋白酶抑制剂来预防或延缓感光细胞变性的可能性。
The retinal degeneration (rd)1 mouse displays an inherited retinal degeneration and therefore allows studies of the molecular mechanisms behind the blinding disease retinitis pigmentosa. Activation of the calcium-dependent protease calpain has been suggested to play an important role in cell death in various tissues, but little is known about the expression and activity of calpain during inherited retinal degeneration. Using microarray techniques, transcript levels of cyclic AMP response element-binding protein (CREB)-1, calpastatin and of various calpain genes were analysed in the rd1 mouse compared with its wild-type control. Expression of distinct calpain isoforms and calpastatin was investigated using immunofluorescence and immunoblotting. Gene transcription and protein expression levels were compared with calpain activity using an enzymatic assay that allowed monitoring of calpain activity at the cellular level. We found that CREB-1 and calpastatin expression was reduced in rd1 retinas, whereas calpain activity was substantially increased in rd1 photoreceptors. Calpain activity peaked at postnatal day 13, together with rd1 photoreceptor cell death. Calpain-specific inhibitors decreased calpain activity in situ. These results indicate that activation of calpains correlates with rd1 photoreceptor cell death, which raises the possibility of using calpain inhibitors to prevent or delay photoreceptor degeneration.