Gag-like Proteins in exosome-mediated Neural Development and Fetal Alcohol Spectrum Disorders

项目摘要 产前酒精暴露（PAE）可导致一系列称为胎儿酒精的脑功能障碍 谱系障碍（FASD）。据估计，FASD影响美国约1-5%的学龄儿童。而 社会文化因素使PAE难以预防，FASD可通过早期干预预防。拟议 研究，旨在确定新的，酒精敏感的大脑生长控制机制介导的一个家庭， Gag样蛋白（GLP）可能会发现新的方法来最大限度地减少PAE的影响。 GLP是古老的逆转录病毒感染的基因组残余物，其已经被改造用于人类的基因组。 宿主生物一些已经进化到控制胚胎干细胞中的转录调控网络， 而另一些像Arc促进分化神经元的可塑性，并被假设为介导 在神经发育障碍如安格尔曼综合征中观察到的一些认知缺陷。Arc也 最近被鉴定为衣壳形成蛋白，其能够在外泌体中转运其自身的mRNA， 神经细胞，让人想起它的Gag起源。其他GLP也可以保留Gag的功能方面，例如 与mRNA相互作用和自我靶向膜结合输出的能力。这些数据引发了令人兴奋的 GLP可能促进RNA的细胞间转移，因此可以作为一种手段， 编程神经干细胞集合的发育和成熟。 初步数据表明，两种GLP（PEG 10和PNMA 2）的表达在胎儿中被选择性诱导， 神经干细胞，酒精暴露。总体假设是，这些GLP，通过两者 细胞内机制和外泌体介导细胞间通讯，控制神经干细胞更新 并促进神经发生，并且由于酒精暴露导致GLP表达的扰动将导致 干细胞更新和减少神经发生的可能性。目前的目标是识别RNA和蛋白质 GLP PEG 10和PNMA 2的伴侣介导乙醇对神经分化和发育的作用。 目的1：确定GAG样蛋白PEG 10和PNMA 2在基础和乙醇中的细胞内作用 影响神经干细胞的分化和神经发育。 目的2：确定PEG 10和存在于外泌体中的其他Gag样蛋白在细胞间 在基础和乙醇条件下神经发育的通信和协调。 目的3：探讨PAG样蛋白与PAE在胚胎神经发育中的相互作用。 这些研究有望发现新的GLP分化介质，可在细胞内进行调控。 外泌体控制神经干细胞集合的自我更新和成熟，并最大限度地减少PAE的影响 早期的神经发育。这个训练计划的重点是破坏PAE和FASD之间的联系 与职业目标很好地结合在一起，成为一名专注于发育障碍的儿科医生-科学家。

Project Summary Prenatal alcohol exposure (PAE) can result in a collection of brain-based disabilities termed Fetal Alcohol Spectrum Disorders (FASD). FASDs are estimated to affect ~1-5% of school-aged children in the US. While sociocultural factors make PAE difficult to prevent, FASD may be prevented by early interventions. The proposed studies, aimed at identifying novel, alcohol-sensitive brain growth control mechanisms mediated by a family of Gag-Like Proteins (GLPs), may uncover new ways to minimize effects of PAE. GLPs are genomic remnants of ancient retroviral infections that have since been adapted for utilization in the host organism. Some have evolved to control transcriptional regulatory networks in embryonic stem cells, whereas others like Arc facilitate plasticity in differentiated neurons, and have been hypothesized to mediate some cognitive deficits observed in neurodevelopmental disorders like Angelman’s syndrome. Arc has also recently been identified as a capsid forming protein capable of transporting its own mRNA in exosomes between neural cells, reminiscent of its Gag origin. Other GLPs may also retain functional aspects of Gag, such as the ability to interact with mRNAs and to self-target for membrane bound export. These data raise the exciting possibility that GLPs may facilitate intercellular transfer of RNAs and therefore serve as a means for programming the development and maturation of neural stem cell ensembles. Preliminary data indicate that expression of two GLPs (PEG10 and PNMA2) are selectively induced in fetal neural stem cells, following alcohol exposure. The overarching hypotheses are that these GLPs, through both intracellular mechanisms and exosome-mediated intercellular communication, control neural stem cell renewal and facilitate neurogenesis, and that perturbations in GLP expression due to alcohol exposure will result in loss of stem cell renewal and diminished neurogenesis. The immediate goal will be to identify RNA and protein partners of GLPs PEG10 and PNMA2 which mediate ethanol-effects on neural differentiation and development. Aim 1: Determine the intracellular role of Gag-like proteins PEG10 and PNMA2 in the basal and ethanol influenced differentiation of neural stem cells and neural development. Aim 2: Determine the extracellular role of PEG10 and other Gag-like proteins present in exosomes in intercellular communication and coordination of neural development under basal and ethanol conditions. Aim 3: Determine the in vivo interaction between Gag-like proteins and PAE on fetal neural development. These studies are expected to uncover novel GLP mediators of differentiation that may be manipulated in exosomes to control self-renewal and maturation of neural stem cell ensembles and to minimize effects of PAE on early neural development. This training plan’s focus on disrupting the connection between PAE and FASD integrates well with a career goal to become a pediatrician-scientist with a focus on developmental disabilities.