Soluble polyglutamine oligomers formed prior to inclusion body formation are cytotoxic.
Soluble polyglutamine oligomers formed prior to inclusion body formation are cytotoxic.
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DOI：
10.1093/hmg/ddm311
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发表时间：
2008-02
影响因子：
3.5
通讯作者：
Toshiaki Takahashi;S. Kikuchi;S. Katada;Y. Nagai;M. Nishizawa;O. Onodera
中科院分区：
文献类型：
--
作者：
Toshiaki Takahashi;S. Kikuchi;S. Katada;Y. Nagai;M. Nishizawa;O. Onodera
扩展的多聚谷氨酰胺（polyQ）重复序列引起神经退行性疾病，但其细胞毒性结构仍有待阐明。虽然可溶性polyQ寡聚体已被提出作为细胞毒性结构，但可溶性polyQ寡聚体而非包涵体（IB）的细胞毒性尚未在活细胞中得到证实。为了阐明可溶性polyQ寡聚体的细胞毒性，我们进行了荧光共振能量转移（FRET）共聚焦显微镜，并在单个活细胞中将寡聚体与单体和IB区分开。当供体和受体荧光蛋白连接到polyQ重复序列的同一侧而不是相对侧时，检测到FRET信号，这与平行β折叠或头对尾圆柱形β折叠模型一致。这些FRET信号在半完整细胞中消失，表明这些polyQ寡聚体是可溶的。PolyQ单体以长度依赖性方式组装成可溶性寡聚体，随后形成IB。值得注意的是，神经元分化细胞的存活测定显示，具有可溶性寡聚体的细胞比具有IB或单体的细胞死亡更快。这些结果表明，寡聚体的长度依赖性形成是polyQ介导的疾病中神经变性的基本机制。
Expanded polyglutamine (polyQ) repeats cause neurodegenerative disorders, but their cytotoxic structures remain to be elucidated. Although soluble polyQ oligomers have been proposed as a cytotoxic structure, the cytotoxicity of soluble polyQ oligomers, not inclusion bodies (IBs), has not been proven in living cells. To clarify the cytotoxicity of soluble polyQ oligomers, we carried our fluorescence resonance energy transfer (FRET) confocal microscopy and distinguished oligomers from monomers and IBs in a single living cell. FRET signals were detected when donor and acceptor fluorescent proteins were attached to the same side, not the opposite side, of polyQ repeats, which agrees with a parallel beta-sheet or a head-to-tail cylindrical beta-sheet model. These FRET signals disappeared in semi-intact cells, indicating that these polyQ oligomers are soluble. PolyQ monomers assembled into soluble oligomers in a length-dependent manner, which was followed by the formation of IBs. Notably, survival assay of neuronally differentiated cells revealed that cells with soluble oligomers died faster than those with IBs or monomers. These results indicate that a length-dependent formation of oligomers is an essential mechanism underlying neurodegeneration in polyQ-mediated disorders.