BRAIN AGING: MOLECULAR EFFECTS OF PERINATAL NUTRITION

项目0001的总体目标是确定受出生前胆碱可获得性支配的大脑重组所涉及的分子机制。目的1是基于胆碱作为甲基供体可以改变体内DNA甲基化和基因表达的证据，验证这一假说，即产前胆碱的可获得性通过改变表达受5-甲基胞嘧啶含量控制的基因的调控元件的DNA甲基化来调节基因表达的发育模式。我们将研究特定基因的DNA甲基化，这些基因在大脑中的表达受出生前胆碱(如胰岛素样生长因子II，lgf2)的调节。目的2是检验产前可获得胆碱改变发育的假设 以及可以通过基因表达谱识别的选定神经元群体的老化。利用寡核苷酸芯片，我们发现，包括受体配体、受体、蛋白激酶和转录因子(如Igf2、GABR1、TrkB、Camk1、Camkllbeta、PKCbeta2和Zif268)在内的多种海马区和大脑皮层基因的表达模式受到产前胆碱可获得性的调节。我们将使用免疫印迹、原位杂交和免疫组织化学(与神经解剖学核心)绘制这些蛋白的表达图，以确定相关的神经元群体。目标3是测试 个体对胆碱的需求取决于基因的假说。与胆碱和甲基代谢有关的几个编码蛋白质的基因在人类中表现出多态性，并导致代谢异常，在某些情况下，可以用营养策略成功地治疗。这些条件的小鼠遗传模型将被用来获得关于胆碱供应的变化可以调节这些动物的表型的机制的信息。将研究四种模型，包括载脂蛋白E(APOE)、磷脂酰乙胺N-甲基转移酶、 亚甲基四氢叶酸还原酶和胆碱脱氢酶。项目3已经显示 在APOE基因缺失的小鼠中观察到的认知缺陷可以通过在整个妊娠期间补充胆碱来挽救，从而为这些研究提供了实验范式。在四种小鼠模型中，我们将确定基因表达模式和信号转导机制，对产前胆碱可获得性的敏感性，包括MAPK和CREB磷酸化和乙酰胆碱转换，以及饮食胆碱对其表型的影响。

The overall goal of Project 0001 is to determine the molecular mechanisms involved in brain reorganization governed by prenatal availability of choline. Aim 1 is to test the hypothesis that prenatal choline availability modulates developmental patterns of gene expression by altering DNA methylation of the regulatory elements of genes whose expression is controlled by 5-methylcytosine content, based on the evidence showing that choline, via its action as a donor of methyl groups, can alter DNA methylation profiles and gene expression in vivo. We will study DNA methylation of selected genes known to be regulated by DNA methylation and whose expression in brain is modulated by prenatal availability of choline (e.g. insulin-like growth factor II, lgf2). Aim 2 is to test the hypothesis that prenatal choline availability alters the development and aging of selected neuronal populations that can be identified by gene expression profiles. Using oligonucleotide microarrays, we found that the expression pattern of multiple hippocampal and cerebral cortical genes, including receptor ligands, receptors, protein kinases, and transcription factors (e.g. Igf2, GABABR1, TrkB, Camkl, Camkllbeta, PKCbeta2, and Zif268), is modulated by the prenatal availability of choline. We will map the expression of these proteins using immunoblotting, in situ hybridization, and immunohistochemistry (with the Neuroanatomy Core) in order to identify the relevant neuronal populations. Aim 3 is to test the hypothesis that individual requirements for choline depend on genotype. Several genes encoding proteins involved in the metabolism of choline and of methyl groups display potymorphism in humans and cause metabolic abnormalities that, in some cases, can be successfully treated with nutritional strategies. Genetic mouse models of these conditions will be used to obtain information on the mechanisms by which alterations in the supply of choline can modulate the phenotype of these animals. Four models will be studied, including mice with targeted mutations in apolipoprotein E (Apoe), phosphatidylethanoamine N-methyltransferease, methylenetetrahydrofolate reductase, and choline dehydrogenase. Project 3 has shown that cognitive defects observed in Apoe null mice can be rescued by choline supplementation throughout gestation, thus providing the experimental paradigm for these studies. In the four mouse models, we will determine gene expression patterns and signal transduction mechanisms, sensitive to prenatal choline availability, including MAPK and CREB phosphorylation and acetylcholine turnover, and the effects of dietary choline on their phenotypes.