mRNA Translation Dysregulation in Neurodevelopmental and Neurodegenerative Diseases (Stephanie Herrlinger)

项目摘要： 越来越多的证据表明，mRNA翻译在各种神经系统疾病中发生改变。然而，在这方面， mRNA失调是否以及如何导致疾病的发生仍然是未知的。小头畸形 是一种在神经发育中出现的疾病，其特征是婴儿的头部尺寸较小， 在美国有10,000名儿童。利用小鼠胚胎脑内接种模型， 已经确定，在大脑发育期间，寨卡病毒的脑内感染可导致 小头畸形。该提案的目的是调查寨卡病毒（ZIKV）感染是否会导致小头畸形 通过mRNA翻译的失调。ZIKV感染导致细胞增殖减少，细胞周期停滞， 和神经祖细胞（NPC）的凋亡增加，这些细胞被认为是最脆弱的， 小头畸形最近的研究报告称，感染寨卡病毒或其他黄病毒家族成员的细胞 登革病毒表现出宿主细胞mRNA的mRNA翻译减少。以前发表的工作有 还表明RNA结合蛋白Lin 28 a的敲除导致NPC自我更新减少， 小鼠的小头畸形利用小鼠遗传工具，本研究描述了Lin 28可以促进NPC 增殖细胞的行为，并且它可以通过调节mRNA翻译来实现。初步证据 进一步表明NPC中mRNA翻译的减少足以引起小头畸形。这些 研究共同表明，在小头畸形的NPC中，mRNA翻译可能是脆弱的， 发现Lin 28 a功能获得和丧失小鼠模型是操纵mRNA的有价值的遗传工具 特别是在NPC中。 这些主要观察结果导致了以下假设：寨卡病毒通过以下途径引起小头畸形： 神经祖细胞中的整体和基因特异性宿主mRNA翻译失调。 为了解决上述假设，将执行以下目标： 1)测试mRNA翻译功能障碍在多大程度上有助于寨卡病毒诱导的小头畸形。到 确定增加NPC中的mRNA翻译是否可以挽救ZIKV诱导的小头畸形，Lin 28 a 过表达小鼠模型将与ZIKV的胚胎接种组合。这将有助于确定 减少宿主细胞mRNA翻译在引起ZIKV诱导的小头畸形中的影响或贡献。 2)确定ZIKV诱导的NPCs中哪些基因在mRNA翻译水平上受到差异调节。 小头畸形。为了研究体内NPC中特异性的mRNA翻译，将使用一种新的小鼠模型， 该HA标记的核糖体蛋白Rp 122将以Cre依赖性方式表达，并且所产生的pull- 将取下样品用于RNA-seq。这将阐明mRNA失调的趋势， 在ZIKV诱导的小头畸形的背景下具有潜在的治疗靶点。

Project Summary: Accumulating evidence suggests that mRNA translation is altered in various neurological disorders. However, it remains largely unknown whether and how mRNA dysregulation contributes to disease onset. Microcephaly is a condition that arises in neurodevelopment characterized by smaller head size in infants that affects 6 in 10,000 children in the United States. Using a model of intracerebral inoculation of mouse embryonic brain, it has been established that intracerebral infection of the Zika virus during brain development can cause Microcephaly. The purpose of this proposal is to investigate if Zika virus (ZIKV) infection induces microcephaly through dysregulation of mRNA translation. ZIKV infection results in reduced cell proliferation, cell cycle arrest, and an increased apoptosis of Neural Progenitor Cells (NPCs), the cells considered to be most vulnerable in microcephaly. Recent work has reported that cells infected with the Zika Virus or other flavivirus family member Dengue Virus exhibit a decrease in mRNA translation of the host cell mRNA. Previously published work has also shown that knockout of the RNA-binding protein Lin28a leads to reduced NPC self-renewal and microcephaly in mice. Using mouse genetic tools, this study described that Lin28 can promote NPC proliferative cell behaviors, and that it may do so through modulating mRNA translation. Preliminary evidence has further suggested that reduced mRNA translation in NPCs is sufficient to cause microcephaly. These studies have collectively suggested that mRNA translation may be vulnerable in NPCs in Microcephaly, and identified that Lin28a gain- and loss-of-function mouse models are valuable genetic tools to manipulate mRNA translation specifically in NPCs. These major observations have led to the following hypothesis: The Zika virus causes Microcephaly through dysregulating global and gene specific host mRNA translation in neural progenitor cells. To address the hypothesis stated above, the following Aims will be performed: 1) Test to what extent mRNA translation dysfunction contributes to Zika virus-induced Microcephaly. To determine if increasing mRNA translation in NPCs can rescue ZIKV-induced microcephaly, the Lin28a overexpression mouse model will be combined with embryonic inoculation of ZIKV. This will help determine the impact or contribution that decreased host cell mRNA translation has in causing ZIKV-induced Microcephaly. 2) Identify what genes are differentially regulated in NPCs at the mRNA translation level in ZIKV-induced Microcephaly. To study mRNA translation specifically in NPCs in vivo, a novel mouse model will be used in which HA-tagged ribosomal protein Rpl22 will be expressed in a Cre-dependent manner and the resulting pull- down sample will be taken for RNA-seq. This will illuminate trends in mRNA dysregulation and provide the field with potential therapeutic targets in the context of ZIKV-induced microcephaly.!