Role of the autophagic-lysosomal system on low potassium-induced apoptosis in cultured cerebellar granule cells
Role of the autophagic-lysosomal system on low potassium-induced apoptosis in cultured cerebellar granule cells
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DOI：
10.1111/j.1471-4159.2004.02956.x
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发表时间：
2005-03-01
影响因子：
4.7
通讯作者：
Calissano, P
中科院分区：
文献类型：
--
作者：
Canu, N;Tufi, R;Calissano, P
根据形态学和生物化学标准，细胞凋亡和自噬性细胞死亡与神经退行性疾病中发生的神经元损失有关，并且已经表明它们可能重叠。我们研究了血清和钾剥夺后小脑颗粒细胞（CGC）凋亡与自噬性细胞死亡之间的关系。我们发现，细胞凋亡是伴随着早期和显着的增殖的自噬体-溶酶体车厢检测电子显微镜和免疫荧光分析。自噬被hrIGF-1和毛喉素阻断，这两种众所周知的CGC细胞凋亡抑制剂，以及被腺病毒介导的Bcl-2过表达阻断。3-甲基腺嘌呤（3-MA）是自噬的抑制剂，它不仅能阻止自噬的发生，还能阻断细胞凋亡. 3-MA的神经保护作用伴随着细胞溶质中细胞色素c（cyt c）释放的阻断和半胱天冬酶-3活化的抑制，而这似乎是由组织蛋白酶B介导的，因为CA 074-Me（该酶的选择性抑制剂）完全阻断了半胱天冬酶原-3的加工。免疫荧光分析表明，组织蛋白酶B，通常局限于内的溶酶体-内体区室，在细胞凋亡过程中释放到胞质溶胶中，这种酶可能作为一种执行蛋白酶。总的来说，这些观察结果表明，自噬先于程序性死亡，并与随后的程序性死亡发生有因果关系。
Apoptotic and autophagic cell death have been implicated, on the basis of morphological and biochemical criteria, in neuronal loss occurring in neurodegenerative diseases and it has been shown that they may overlap. We have studied the relationship between apoptosis and autophagic cell death in cerebellar granule cells (CGCs) undergoing apoptosis following serum and potassium deprivation. We found that apoptosis is accompanied by an early and marked proliferation of autophagosomal-lysosomal compartments as detected by electron microscopy and immunofluorescence analysis. Autophagy is blocked by hrIGF-1 and forskolin, two well-known inhibitors of CGC apoptosis, as well as by adenovirus-mediated overexpression of Bcl-2. 3-Methyladenine (3-MA) an inhibitor of autophagy, not only arrests this event but it also blocks apoptosis. The neuroprotective effect of 3-MA is accompanied by block of cytochrome c (cyt c) release in the cytosol and by inhibition of caspase-3 activation which, in turn, appears to be mediated by cathepsin B, as CA074-Me, a selective inhibitor of this enzyme, fully blocks the processing of pro-caspase-3. Immunofluorescence analysis demonstratesd that cathepsin B, normally confined inside the lysosomal-endosomal compartment, is released during apoptosis into the cytosol where this enzyme may act as an execution protease. Collectively, these observations indicate that autophagy precedes and is causally connected with the subsequent onset of programmed death.