FET proteins TAF15 and EWS are selective markers that distinguish FTLD with FUS pathology from amyotrophic lateral sclerosis with FUS mutations
FET proteins TAF15 and EWS are selective markers that distinguish FTLD with FUS pathology from amyotrophic lateral sclerosis with FUS mutations
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DOI：
10.1093/brain/awr201
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发表时间：
2011-09-01
期刊：
影响因子：
14.5
通讯作者：
Mackenzie, Ian R. A.
中科院分区：
文献类型：
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作者：
Neumann, Manuela;Bentmann, Eva;Mackenzie, Ian R. A.
所有肌萎缩性侧索硬化症（肌萎缩性侧索硬化症）患者以及额颞叶变性的几种亚型（与FUS突变无关）的FUS突变患者的病理特征是，肉瘤中以细胞质包涵体形式融合的DNA/RNA结合蛋白在神经元和神经胶质细胞中积累。导致包涵体形成和融合的机制在肉瘤相关的神经退行性变只是知之甚少。由于融合肉瘤属于FET蛋白家族，该家族还包括尤文氏肉瘤和tata结合蛋白相关因子15，因此我们研究了这些FET蛋白家族成员在融合肉瘤蛋白病变发病机制中的潜在参与。FET蛋白的免疫组织化学分析揭示了不同情况下FET蛋白的显著差异，在肌萎缩侧索硬化症中，FUS突变被标记为仅融合在肉瘤中，而在额颞叶变性亚型中，融合在肉瘤阳性包涵体中，也一致地对塔塔结合蛋白相关因子15进行免疫染色，并对尤文氏肉瘤进行不同的免疫染色。免疫印迹分析从伴有肉瘤病理融合的额颞叶变性患者的死后组织中提取的蛋白质表明，所有FET蛋白都向不溶性蛋白部分相对转移，而对tata结合蛋白相关因子15和Ewing肉瘤基因的遗传分析未发现任何致病变异。细胞培养实验证实了肌萎缩性侧索硬化症合并FUS突变的结果，证实了tata结合蛋白相关因子15的缺失，以及肉瘤中融合突变表达后的尤文氏肉瘤改变。相比之下，所有内源性FET蛋白都在转运蛋白介导的核输入普遍抑制的情况下被招募到细胞质应激颗粒中，这与合并肉瘤病理的额颞叶变性相似。这些结果可以根据神经病理特征区分由FUS突变引起的融合肉瘤蛋白病变和那些没有已知遗传原因的肉瘤蛋白病变。更重要的是，我们的数据表明两种情况下包涵体形成和细胞死亡的病理过程不同；肌萎缩性侧索硬化症合并FUS突变的发病机制似乎更局限于肉瘤融合功能障碍，而所有FET蛋白的更全面和复杂的失调与融合肉瘤病理的额颞叶变性亚型有关。
Accumulation of the DNA/RNA binding protein fused in sarcoma as cytoplasmic inclusions in neurons and glial cells is the pathological hallmark of all patients with amyotrophic lateral sclerosis with mutations in FUS as well as in several subtypes of frontotemporal lobar degeneration, which are not associated with FUS mutations. The mechanisms leading to inclusion formation and fused in sarcoma-associated neurodegeneration are only poorly understood. Because fused in sarcoma belongs to a family of proteins known as FET, which also includes Ewing's sarcoma and TATA-binding protein-associated factor 15, we investigated the potential involvement of these other FET protein family members in the pathogenesis of fused in sarcoma proteinopathies. Immunohistochemical analysis of FET proteins revealed a striking difference among the various conditions, with pathology in amyotrophic lateral sclerosis with FUS mutations being labelled exclusively for fused in sarcoma, whereas fused in sarcoma-positive inclusions in subtypes of frontotemporal lobar degeneration also consistently immunostained for TATA-binding protein-associated factor 15 and variably for Ewing's sarcoma. Immunoblot analysis of proteins extracted from post-mortem tissue of frontotemporal lobar degeneration with fused in sarcoma pathology demonstrated a relative shift of all FET proteins towards insoluble protein fractions, while genetic analysis of the TATA-binding protein-associated factor 15 and Ewing's sarcoma gene did not identify any pathogenic variants. Cell culture experiments replicated the findings of amyotrophic lateral sclerosis with FUS mutations by confirming the absence of TATA-binding protein-associated factor 15 and Ewing's sarcoma alterations upon expression of mutant fused in sarcoma. In contrast, all endogenous FET proteins were recruited into cytoplasmic stress granules upon general inhibition of Transportin-mediated nuclear import, mimicking the findings in frontotemporal lobar degeneration with fused in sarcoma pathology. These results allow a separation of fused in sarcoma proteinopathies caused by FUS mutations from those without a known genetic cause based on neuropathological features. More importantly, our data imply different pathological processes underlying inclusion formation and cell death between both conditions; the pathogenesis in amyotrophic lateral sclerosis with FUS mutations appears to be more restricted to dysfunction of fused in sarcoma, while a more global and complex dysregulation of all FET proteins is involved in the subtypes of frontotemporal lobar degeneration with fused in sarcoma pathology.