BRAIN AGING--MOLECULAR EFFECTS OF PERINATAL NUTRITION

项目1的总体目标是确定大脑重组所涉及的分子机制，这些机制受出生前胆碱或叶酸的可获得性和载脂蛋白E(ApoE)基因控制。我们发现，在大鼠妊娠的后半期，胆碱的供应会引起脑内生化、结构和电生理的变化，以及深刻的行为改变。总体而言，年轻的成年和老年大鼠产前补充胆碱，在测量记忆和注意力的任务中，相对于对照组和产前缺陷的动物，表现有所改善。相比之下，胎儿期缺陷的动物在测量记忆和注意力的注意力任务中受到损害。相比之下，出生前缺陷的动物在注意力任务中受到损害，但在记忆任务中有所改善。对数据进行的研究表明，产前胆碱的可获得性可能会影响大脑中多个突触信号通路的发展。具体地说，产前胆碱的可获得性改变了海马区的长期潜力、乙酰胆碱(ACh)周转、磷脂酶D活性和神经生长因子信号转导指数。我们将确定胎儿期胆碱和叶酸在发育、成年期和衰老过程中对大脑信号转导系统的影响。到目前为止进行的研究表明，产前胆碱的可获得性改变了发育中大脑的有丝分裂和凋亡模式，以及几种蛋白质的表达模式。这些数据与我们的假设是一致的，即产前获得必要的营养物质会导致大脑组织的多种变化。我们建议使用与高密度寡核苷酸阵列的杂交和反向Northern分析来确定脑基因表达的发育模式，然后对所识别的基因进行原位杂交分析。叶酸和胆碱的代谢是高度相关的；因此，叶酸的有效性对大脑ACh周转的影响将被研究。在大脑内，胆碱可以通过一种涉及载脂蛋白A介导的含胆碱的脂质运输的机制在细胞之间重新分配。卵磷脂(PC)。我们将确定ApoE-/-小鼠的大脑ACh周转是否发生改变。我们将研究膳食胆碱改变叶酸缺乏和载脂蛋白E-/-动物ACh代谢的可能性。此外，我们建议使用CULL培养模型来确定含apoE的脂蛋白是否可以向胆碱能神经元供应PC。

The overall goal of Project 1 is to determine the molecular mechanisms involved in brain reorganization governed by prenatal availability of choline or folic acid and by apolipoprotein E (apoE) genotype. We have found that the availability of choline during the second half of gestation in rats causes biochemical, structural and electrophysiologic changes in brain as well as profound behavioral modifications.. In general, young adult and aged rats supplemented prenatally with choline and improved performance relative to control and prenatally-deficient animals in tasks measuring memory and attention. In contrast,, prenatally deficient animals were impaired in attentional tasks measuring memory and attention. In contrast, prenatally deficient animals were impaired in attentional tasks but somewhat improved in memory tasks. Studies performed to data indicated that prenatal availability of choline may affect the development of multiple synaptic signaling pathways in brain. Specifically prenatal choline availability modifies hippocampal long-term potential,.acetylcholine (ACh) turnover, phospholipase D activity, and indices of nerve growth factor signaling. We will determine the effects of prenatal choline availability and folate availability on signal transduction systems in brain during development, adulthood and aging. Studies performed to date show that prenatal availability of choline alters the patterns of mitosis and apoptosis in developing brain as well as patterns of expression of several proteins. These data are consistent with our hypothesis that prenatal availability of essential nutrients causes multiple changes in brain organization. We propose to determine the developmental patterns of expression of brain genes using hybridization to high density oligonucleotide arrays and reverse Northern analysis followed by in situ hybridization assays of thus identified genes. The metabolism of folate and choline are highly interrelated; therefore the effects of folate availability on ACh turnover in brain will be examined. Within the brain, choline may be redistribut4ed between cells by a mechanism involving apolipoprotein A-mediated transport of a choline- containing lipid. phosphatidylcholine (PC). We will determine if brain ACh turnover is altered in ApoE-/- mice. We will investigate the possibility that dietary choline will modify ACh turnover in folate deficient and ApoE-/- animals. In addition we propose to determine if apoE-containing lipoproteins can supply PC to cholinergic neurons using a cull culture model.