Contribution of astrocytes to mutant FUS-linked Amyotrophic Lateral Sclerosis

摘要 本项目的目标是确定融合基因突变的机制， 肉瘤（FUS）诱导FUS相关星形胶质细胞的病理和致病性变化， 肌萎缩侧索硬化症（FUS-ALS）。 已知星形胶质细胞在一些但不是所有形式的疾病中促进疾病进展。 直到最近，人们对星形胶质细胞在FUS-ALS中的作用知之甚少。 我们的实验室最近发表了第一个体外证据， FUS的突变形式（mutFUS），而不是野生型FUS，对运动神经元产生毒性 通过激活NFkB途径导致分泌因子的释放，和 主要是TNFα（Kia & McAb等人，GLIA，2018）。以TNFα依赖的方式，运动 暴露于mutFUS星形胶质细胞条件培养基的神经元显示AMPA受体 这些改变使它们对兴奋性毒性损伤敏感，导致细胞死亡。激活 星形胶质细胞NFkB和TNFα的释放似乎对mutFUS-ALS具有特异性，强调了 剖析每种形式的ALS特有的疾病机制的重要性， 来开发量身定制的疗法。 在本提案中，我们将关注mutFUS-ALS，并将通过以下方式研究（1）机制： FUS中哪些疾病诱发突变改变星形胶质细胞生物学和（2）突变如何改变星形胶质细胞生物学 表达FUS的星形胶质细胞影响体内脊髓中其他细胞的活力。的 最终目标是确定mutFUS靶向的关键途径， 具体治疗。最终，我们的FUS-ALS模型可以作为一个平台， 与模拟其他形式ALS的模型进行比较分析，以确定基因型- 疾病发病机制的特异性与聚合性和更全面的机制。为我们 研究中，我们将使用体外和体内模型，包括（1）原代啮齿动物星形胶质细胞 以及来自FUS的iPSC衍生的星形胶质细胞 （2）mutFUS ALS的体内小鼠模型。体外系统可以让我们 剖析mutFUS靶向星形胶质细胞的精确机制， 确定mutFUS如何改变患者的星形胶质细胞生物学。小鼠模型将允许 我们研究mutFUS星形胶质细胞如何影响体内复杂的细胞环境， 设置.

ABSTRACT The goal of this project is to identify the mechanisms by which mutations in Fused in Sarcoma (FUS) induce pathological and pathogenic changes in astrocytes in FUS-linked Amyotrophic Lateral Sclerosis (FUS-ALS). Astrocytes are known to contribute to disease progression in some, but not all, forms of ALS and, until recently, not much was known about the role of astrocytes in FUS-ALS. Our lab has recently published the first in vitro evidence that astrocytes expressing mutant forms of FUS (mutFUS), but not wild-type FUS, exert toxicity on motor neurons through activation of the NFkB pathway leading to the release of secreted factor(s), and primarily TNFα (Kia & McAvoy et al., GLIA, 2018). In a TNFα−dependent manner, motor neurons exposed to the conditioned medium of mutFUS astrocytes show AMPA receptor alterations that sensitize them to excitotoxic damage, leading to cell death. Activation of astrocytic NFkB and TNFα release seems to be specific to mutFUS-ALS, underscoring the importance of dissecting disease mechanisms specific to each form of ALS in order to develop tailored therapies. In this proposal, we will focus on mutFUS-ALS and will study (1) the mechanisms by which disease-casuative mutations in FUS alter astrocyte biology and (2) how mutant FUS expressing astrocyte affect the viability of other cells in the spinal cord in vivo. The ultimate goal is to identify key pathways targeted by mutFUS to eventually develop specific therapies. Ultimately, our models of FUS-ALS may serve as a platform for a comparative analysis with models mimicking other forms of ALS, so to identify genotype- specific vs. converging and more global mechanisms of disease pathogenesis. For our studies, we will use in vitro and in vivo models consisting of (1) primary rodent astrocytes transduced with different FUS mutations as well as iPSc-derived astrocytes from FUS patients; (2) an in vivo mouse model of mutFUS ALS. The in vitro systems will allow us to dissect the precise mechanisms by which mutFUS targets the astrocytes and to determine how mutFUS alters astrocyte biology in patients. The mouse model will allow us to study how mutFUS astrocytes affect the cellular environment in a complex in vivo setting.