Effect of Ethanol on Cell Proliferation

了解乙醇对神经干细胞的影响对于解开缺陷的病因之结至关重要。 与胎儿酒精谱系障碍(FASD)有关。FASD是一个引人注目的问题，因为它是一个主要的 影响约2%活产的发育性精神障碍的原因(实际上，这是精神疾病的主要原因 在美国)，它提供了对其他(通常是并存的)精神健康障碍的病因学的见解 (例如，注意力缺陷多动障碍和自闭症)。大脑的组成和大小已经确定 由神经干细胞的增殖和衍生品的数量和谱系决定。号码不正确或 神经元亚群的平衡可能是精神功能障碍的基础。因此，我们将检验乙醇的假设 影响发育中的中枢神经系统产生的细胞的循环行为和命运。 大脑皮质由两种类型的神经元组成：兴奋性投射神经元和抑制性局部神经元 回路神经元(LCNs)。这些胎盘起源于两个不同的增殖区。三叉神经核来自背侧 端脑，包括两个区：脑室区(VZ)及其衍生的脑室下区 (深圳)。大多数皮质LCNs产生于端脑腹侧，位于内侧神经节隆起(MGE)。 VZ/SZ和MGe电池的命运在两步过程中确定。(1)决定单元格是否保留 在循环种群中，(2)定义表型(例如，神经元类型)。在上一时期内 此外，我们还发现转化生长因子β1是神经干细胞增殖的关键调节因子。 本项目将探索乙醇对细胞增殖动力学的影响以及对 细胞的命运。特定的AIMS 1和2将使用体内模型来确定乙醇对循环活动的影响 (细胞周期动力学和退出)以及皮质神经干细胞对转化生长因子β受体表达/激活的影响 增殖区。在发育过程中，神经干细胞表达一种同源异型盒基因产物(S)、Pax6和/或 Tbr2.这些蛋白质决定了VZ中的(Pax6+)干细胞向(Tbr2+)中间祖细胞的转变 细胞阶段。这一转变对浅层皮质的发育至关重要(例如，胼胝体投射的起源)。 这是产前接触乙醇的目标。特殊目标3将使用两种类型的培养(器官型切片 在体内保留从VZ/SZ或MGE获得的神经干细胞的组织和系)，以探索 乙醇对TGFbeta1调控的细胞增殖和命运决定的影响。此外，我们将识别出 上调和下调，并被乙醇和/或转化生长因子β1沉默(甲基化)。在特定目标4中，神经干细胞 将进行细胞移植(同位或异位)，以确定乙醇和/或转化生长因子β1对 基因和环境对决定循环行为和定义细胞命运的贡献。 同时，新的AIMS将使用三个互补的模型来获得对定义 细胞增殖和命运以及乙醇对这些关键因素的影响。

Understanding the effects of ethanol on neural stem cells is critical to unraveling the etiological knots of deficits associated with fetal alcohol spectrum disorder (FASD). FASD is a compelling problem because it is a major cause of developmental mental dysfunction affecting ~2% of all live births (indeed, it is the chief cause of mental retardation in the USA), and it provides insights into the etiology of other (often co-morbid) mental health disorders (e.g., attention deficit hyperactivity disorder and autism). The composition and size of the brain are established by the proliferation of neural stem cells and by the numbers and lineage of the derivatives. Improper numbers or balance of neuronal subpopulations can underlie mental dysfunction. Thus, we will test the hypothesis that ethanol affects the cycling behavior and fates of cells generated in the developing central nervous system. Cerebral cortex is composed of two types of neurons: excitatory projection neurons (PNs) and inhibitory local circuit neurons (LCNs). These derive prenatally from two distinct proliferative regions. PNs come from the dorsal telencephalon which comprises two zones: the ventricular zone (VZ) and its derivative, the subventricular zone (SZ). Most cortical LCNs are generated in the ventral telencephalon, in the medial ganglionic eminence (MGE). The fates of VZ/SZ and MGE cells are defined in a two-step process. (1) It is decided whether the cells remain in the cycling population and (2) the phenotype (e.g., the type of neuron) is defined. During the previous period of support, we showed that transforming growth factor (TGF) beta1 is a key regulator of neural stem cell proliferation. The present project will explore the effects of ethanol on dynamics of cell proliferation and on the definition of cell fate. Specific Aims 1 and 2 will use an in vivo model to determine the effects of ethanol on the cycling activity (cell cycle kinetics and exit) and on the expression/activation of TGFbeta receptors by neural stem cells in the cortical proliferative zones. During their development, neural stem cells express a homeobox gene product(s), Pax6 and/or Tbr2. These proteins define the transition from (Pax6+) stem cells in the VZ to an (Tbr2+) intermediate progenitor cell stage. This transition is critical for the development of superficial cortex (e.g., the origin of callosal projections) which is a target of prenatal exposure to ethanol. Specific Aim 3 will use two types of cultures (organotypic slices that retain in vivo-like organization and lines of neural stem cells harvested from the VZ/SZ or MGE) to explore the effects of ethanol on TGFbeta1-regulated cell proliferation and fate decisions. In addition, we will identify genes that are up- and down-regulated and silenced (methylated) by ethanol and/or TGFbeta1. In Specific Aim 4, neural stem cells will be transplanted (homotopically or heterotopically) to determine the effects of ethanol and/or TGFbeta1 on genetic and environmental contributions to determining cycling behavior and to defining cell fate. In concert, the novel Aims will use three complementary models to gain critical insight into mechanisms defining cell proliferation and fate and the effects of ethanol on these critical factors.