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部残疾 频谱障碍(FASD)。据估计，在美国，大约1-5%的学龄儿童会受到FASD的影响。而当 社会文化因素使PAE难以预防，FASD可通过早期干预预防。建议数 研究旨在确定由一个家族介导的新颖的、酒精敏感的脑生长控制机制 类Gag蛋白(GLP)，可能发现将PAE的影响降至最低的新方法。 GLP是古老的逆转录病毒感染的基因组残留物，后来被改造成用于 寄主生物体。其中一些已经进化到控制胚胎干细胞的转录调控网络， 而其他的如Arc促进分化的神经元的可塑性，并被假设为 在安杰曼综合症等神经发育障碍中观察到一些认知缺陷。ARC也有 最近被发现是一种衣壳形成蛋白，能够在外体之间转运自己的mRNAs 神经细胞，让人想起它的恶作剧起源。其他GLP也可能保留GAG的功能方面，例如 能够与mRNAs相互作用，并自我定位于膜结合的出口。这些数据提高了令人兴奋的 GLP可能促进RNA的细胞间转移，从而作为一种手段 规划神经干细胞群的发展和成熟。 初步数据表明，两个GLP(PEG10和PNMA2)在胎儿中被选择性地诱导表达 神经干细胞，在酒精暴露后。最重要的假设是，这些GLP，通过两者 细胞内机制和外体介导的细胞间通讯，控制神经干细胞更新 并促进神经发生，而酒精暴露引起的GLP表达紊乱将导致丢失 干细胞更新和神经发生减少。近期的目标将是识别RNA和蛋白质 GLPs PEG10和PNMA2的伙伴，它们介导乙醇-对神经分化和发育的影响。 目的1：确定GAG样蛋白PEG10和PNMA2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PEG10和其他存在于外切体中的类Gag蛋白在细胞间的细胞外作用 基础和乙醇条件下神经发育的沟通和协调。 目的3：研究GAG样蛋白与PAE在体内对胎儿神经发育的影响。 这些研究有望发现新的GLP分化介质，这些介质可能在 外体控制神经干细胞群的自我更新和成熟，并将PAE的影响降至最低 关于早期神经发育的。本培训计划的重点是破坏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和科学家。

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.