Activation of neuronal caspase-3 by intracellular accumulation of wild-type Alzheimer amyloid precursor protein
Activation of neuronal caspase-3 by intracellular accumulation of wild-type Alzheimer amyloid precursor protein
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DOI：
10.1523/jneurosci.19-16-06955.1999
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发表时间：
1999-08-15
影响因子：
5.3
通讯作者：
Yoshikawa, K
中科院分区：
文献类型：
--
作者：
Uetsuki, T;Takemoto, K;Yoshikawa, K
野生型阿尔茨海默淀粉样蛋白（APP）的过度表达导致有丝分裂后神经元变性。Caspase-3 （CPP32）是一种主要的细胞死亡蛋白酶，在生理发育和病理条件下参与神经元凋亡。在这里，我们通过腺病毒介导的基因转移研究了APP过表达是否激活了人类有丝分裂后神经元中的caspase-3。将表达人野生型APP695的重组腺病毒载体体外感染神经分化的胚胎癌NT2细胞，只有有丝分裂后神经元发生严重变性。在神经退行性变前，感染的神经元中积累了全长APP-和A - β免疫反应肽，caspase-3样蛋白酶活性明显升高。Western blot分析显示，app积累神经元中产生了活化的caspase-3亚基。这种神经元caspase-3激活在被表达β -半乳糖苷酶的腺病毒感染的NT2神经元中检测不到。在培养基中加入caspase-3抑制剂乙酰- asp - glu - val - asp -醛，可显著降低过表达app的神经元的退化程度。免疫细胞化学分析显示，部分app积累神经元含有活化的caspase-3亚基，并表现出染色质凝聚和DNA断裂等凋亡特征。应用表达app的腺病毒感染大鼠海马神经元后，在体内也观察到caspase-3的活化。这些结果表明，野生型APP是有丝分裂后神经元中caspase-3介导的死亡机制的内在激活因子。
Forced overexpression of wild-type Alzheimer amyloid precursor protein (APP) causes postmitotic neurons to degenerate. Caspase-3 (CPP32) is a principal cell death protease involved in neuronal apoptosis during physiological development and under pathological conditions. Here, we investigated whether APP overexpression activates caspase-3 in human postmitotic neurons using adenovirus-mediated gene transfer. When a recombinant adenovirus vector expressing human wild-type APP695 was infected in vitro into neurally differentiated embryonal carcinoma NT2 cells, only postmitotic neurons underwent severe degeneration. Before neurodegeneration, full-length APP- and A beta-immunoreactive peptides were accumulated in infected neurons, and caspase-3-like protease activity was markedly elevated. Western blot analysis revealed that activated caspase-3 subunits were generated in APP-accumulating neurons. Such neuronal caspase-3 activation was undetectable in NT2 neurons infected with beta-galactosidase-expressing adenovirus. Addition of the caspase-3 inhibitor acetyl-Asp-Glu-Val-Asp-aldehyde to the culture medium significantly reduced the severity of degeneration exhibited by APP-overexpressing neurons. Immunocytochemical analyses revealed that some APP-accumulating neurons contained activated caspase-3 subunits and exhibited the characteristics of apoptosis, such as chromatin condensation and DNA fragmentation. Activation of caspase-3 was also observed in vivo in rat hippocampal neurons infected with the APP-expressing adenovirus. These results suggest that wild-type APP is an intrinsic activator of caspase-3-mediated death machinery in postmitotic neurons.