Adenovirus-mediated expression of mutant DRPLA proteins with expanded polyglutamine stretches in neuronally differentiated PC12 cells. Preferential intranuclear aggregate formation and apoptosis
Adenovirus-mediated expression of mutant DRPLA proteins with expanded polyglutamine stretches in neuronally differentiated PC12 cells. Preferential intranuclear aggregate formation and apoptosis
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DOI：
10.1093/hmg/8.6.997
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发表时间：
1999-06-01
影响因子：
3.5
通讯作者：
Tsuji, S
中科院分区：
文献类型：
--
作者：
Sato, A;Shimohata, T;Tsuji, S
为了研究齿状红核-苍白球卢伊西亚萎缩症 (DRPLA) 中 CAG 重复序列扩增引起的神经变性的分子机制，DRPLA 是一种常染色体显性遗传性神经退行性疾病，由 12p13.31 上 DRPLA 基因中的 CAG 三核苷酸重复不稳定扩增引起，我们在神经元分化的 PC12 细胞和使用腺病毒表达系统的成纤维细胞。尽管在神经元分化的 PC12 细胞和用 Q82 表达截短的 DRPLA 蛋白的成纤维细胞中均观察到聚集体形成，但 >97% (n = 3) 的神经元分化的 PC12 细胞显示核内包涵体，而只有 31 +/- 21% (n = 3) 的成纤维细胞在感染后 3 天有核内包涵体。在表达带有 Q82 的截短 DRPLA 蛋白的神经元分化 PC12 细胞中，凋亡细胞的百分比显着高于成纤维细胞，这表明核内聚集体可能优先在神经元分化的 PC12 细胞中形成，并且这些细胞比成纤维细胞更容易受到 DRPLA 蛋白中扩展的聚谷氨酰胺延伸段的毒性作用。当带有Q82的全长DRPLA蛋白表达时，聚集体仅出现在神经元分化的PC12细胞的细胞核中，而它们出现在成纤维细胞的细胞质中。尽管存在聚集体，但在神经元分化的 PC12 细胞或成纤维细胞中表达全长 DRPLA 蛋白和 Q82 并不诱导细胞凋亡，这表明核内聚集体的存在本身不一定对细胞有毒。
To investigate the molecular mechanisms of neuro- degeneration caused by expanded CAG repeats in dentatorubral-pallidoluysian atrophy (DRPLA), an autosomal dominant neurodegenerative disorder caused by unstable expansion of a CAG trinucleotide repeat in the DRPLA gene on 12p13.31, we established an efficient expression system for truncated and full-length DRPLA proteins with normal or expanded polyglutamine stretches in neuronally differentiated PC12 cells and fibroblasts using an adenovirus expression system. Although aggregate body formation was observed both in neuronally differentiated PC12 cells and in fibroblasts expressing truncated DRPLA proteins with Q82, >97% (n = 3) of neuronally differentiated PC12 cells showed intranuclear inclusions, while only 31 +/- 21% (n = 3) of fibroblasts had intranuclear inclusions at 3 days after infection. The percentage of apoptotic cells was significantly higher in neuronally differentiated PC12 cells expressing the truncated DRPLA protein with Q82 than in fibroblasts, suggesting the possibility that intranuclear aggregate bodies are formed preferentially in neuronally differentiated PC12 cells and that these cells are more vulnerable than fibroblasts to the toxic effects of expanded polyglutamine stretches in the DRPLA protein. When the full-length DRPLA protein with Q82 was expressed, aggregate bodies were found exclusively in the nuclei of the neuronally differentiated PC12 cells, while they were found in the cytoplasm of fibroblasts. Despite the presence of aggregate bodies, apoptosis was not induced by expression of the full-length DRPLA protein with Q82 in either neuronally differentiated PC12 cells or fibroblasts, suggesting that the presence of intranuclear aggregate bodies is in itself not necessarily toxic to cells.