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FUS在突触后神经肌肉接头分化中的作用

Role of FUS in post synaptic neuromuscular junction differentiation
课程网址: http://videolectures.net/encals2017_picchiarelli_junction_differe...  
主讲教师: Gina Picchiarelli
开课单位: 医学研究所
开课时间: 2017-07-21
课程语种: 英语
中文简介:
在ALS疾病的进展过程中,神经肌肉接头(NMJ),即运动神经元和肌肉纤维之间的特殊突触,是第一个受到影响的结构。事实上,NMJ在运动神经元细胞体退化之前被拆除。我们实验室的结果还表明ALS患者和模型中观察到的神经退行性变中存在肌肉代谢缺陷。ALS病例的一部分是由编码FUS基因的显性遗传突变引起的,FUS是一种RNA结合蛋白,参与RNA代谢的多个步骤。ALS相关的FUS突变导致典型的ALS,发病年轻且疾病进展迅速。大多数已知的FUS突变改变了FUS在细胞核中的输入,导致最严重临床表现的突变是截断突变,删除C末端核定位信号(NLS)。我们的实验室先前开发了ALS的条件Fus敲入模型(Scekic-Zahirovic等人,EMBO J,2016;Scekic-Zahirovic,神经病理学报,2017)。这些小鼠表现出NLS的组成性缺失,可在CRE介导的重组后被拯救到野生型情况。我们观察到纯合子敲除小鼠中FUS的完全细胞质错误定位导致围产期死亡,并伴有运动神经元变性。有趣的是,挽救运动神经元中的FUS定位挽救了运动神经元变性,但并未挽救围产期死亡。我们的工作假设是Fus突变主要导致NMJ结构和分化缺陷。事实上,在细胞模型中,FUS对于驱动NMJ的乙酰胆碱受体基因的表达是必要的,并且在动物模型中,FUS完全错误定位显示NMJ的超微结构突触前缺陷。除了突触前缺陷外,这些小鼠的肌肉表现出异常的突触后乙酰胆碱受体簇,这与肌肉中许多NMJ相关基因的表达缺陷有关。此外,小鼠中的成年杂合子Fus敲除显示Fus的部分细胞质定位错误,显示较小的终板。因此,正常的神经肌肉接头分化需要适当的FUS功能。了解FUS在NMJ结构和功能中的作用有助于设计FUS-ALS的治疗策略。
课程简介: During ALS disease progression, the neuromuscular junction (NMJ), that is the specialized synapse between the motor neuron and the muscle fiber, is the first structure to be affected. Indeed, the NMJ is dismantled before degeneration of motor neuron cell body. Results from our laboratory also implicate muscle metabolic defects in the neurodegeneration observed in ALS patients and models. A subset of ALS cases is caused by dominantly inherited mutations in the gene encoding FUS, a RNA-binding protein involved in multiple steps of RNA metabolism. ALS-linked FUS mutations cause typical ALS, with young onset and rapid disease progression. Most of the known FUS mutations alter the import of FUS in the nucleus, and the mutations leading to the most severe clinical pictures are truncating mutations deleting the C-terminal nuclear localization signal (NLS). Our laboratory previously developed a conditional Fus Knock-In model of ALS (Scekic-Zahirovic et al., EMBO J, 2016; Scekic- Zahirovic, Acta Neuropathol, 2017). These mice display a constitutive deletion of NLS that can be rescued to the wild type situation upon CRE-mediated recombination. We observed that the complete cytoplasmic mislocalization of FUS in homozygous Knock-In mice leads to perinatal death, accompanied by motor neuron degeneration. Interestingly, rescuing FUS localization in motor neurons rescued motor neuron degeneration, yet perinatal death was not rescued. Our working hypothesis is that Fus mutation is primarily causing defects in NMJ structure and differentiation. Indeed in a cell model, FUS is both necessary and sufficient to drive expression of acetylcholine receptor genes of the NMJ and in an animal model, complete Fus mislocalization showed ultrastructural presynaptic defects at the NMJ. Besides presynaptic defects, muscles of these mice showed abnormal post-synaptic acetylcholine receptor clusters, and this was associated with defects in expression of a number of NMJ-related genes in muscles. Furthermore, adult heterozygous Fus knock-in mice, showing partial cytoplasmic mislocalization of FUS, display smaller endplates. So, proper FUS function is required for the normal neuromuscular junction differentiation. The understanding of the role of FUS in NMJ structure and function could be instrumental in designing therapeutic strategies for FUS-ALS.
关 键 词: ALS; 神经肌肉接头; 运动神经元细胞
课程来源: 视频讲座网
数据采集: 2021-12-11:zkj
最后编审: 2021-12-11:zkj
阅读次数: 62