Role of MicroRNAs in Fetal Alcohol Syndrome

描述(申请人提供)：怀孕期间滥用酒精会对发育中的胎儿产生深远的影响，导致胎儿酒精综合症(FAS)。酒精尤其会损害发育中的大脑，导致小脑、智力迟缓和多动。Fas是导致智力低下的主要原因之一，是一个主要的公共卫生问题。在发育中的大脑中，神经元死亡是酒精最显著的病理效应之一，这种神经元的丧失是与该综合征相关的许多行为缺陷的基础。在大脑生长突变期，神经元对酒精引起的死亡特别敏感，这是大脑快速增长的时期，在此期间，许多神经元通过延伸轴突和形成突触连接而在形态上成熟。为什么发育中的神经元在大脑生长激增期间特别容易受到酒精的影响尚不清楚，但可能是由于酒精和调节神经元形态发育的基因表达模式之间的相互作用。MicroRNAs是一种小的、非编码的RNAs，通过控制许多基因的表达来调节中枢神经系统的发育。两个对大脑发育特别重要的microRNA是microRNA-132(miR-132)和miR-124，它们都富含在大脑中，调节神经元的形态发生和轴突的生长。这一提议的中心假设是，酒精通过干扰miR-132和miR-124的表达，扰乱神经元的成熟，使神经元容易受到酒精毒性的影响。因此，这一提议的实验将侧重于酒精与这些微小RNA在大脑发育过程中的相互作用。在这项提案中，我们将确定miR-132和miR-124的表达是否受发育调控，它们的表达水平是否与酒精脆弱期有关，以及酒精是否影响它们的表达。我们还将确定miR-132和miR-124的实验操作是否会改变神经元的形态和对酒精的脆弱性。我们将确定这些microRNAs的异位表达是否促进轴突生长并保护发育中的神经元免受酒精毒性。相反，我们将确定miR-132和miR-124的沉默是否会损害轴突生长，并增加发育中的神经元对酒精诱导的细胞死亡的易感性。因此，这些研究将考察酒精对两个相关和重要的microRNAs的影响，并确定它们在依赖成熟的酒精抵抗中的作用，这是Fas中的一个基本重要现象。 公共卫生意义：怀孕期间酗酒会对发育中的胎儿产生深远影响，导致胎儿酒精综合征(FAS)。酒精损害发育中的大脑，导致小脑、智力迟缓和多动。在这项建议中，我们将研究酒精对microRNAs的影响，microRNAs是控制与神经元形态成熟有关的几个基因表达的主开关。

DESCRIPTION (provided by applicant): Alcohol abuse during pregnancy can profoundly affect the developing fetus, resulting in fetal alcohol syndrome (FAS). Alcohol particularly damages the developing brain, leading to microencephaly, mental retardation, and hyperactivity. One of the leading causes of mental retardation, FAS is a major public health problem. In the developing brain, neuronal death is one of alcohol's most prominent pathologic effects, and this loss of neurons underlies many of the behavioral deficits associated with the syndrome. Neurons are particularly sensitive to alcohol-induced death during the brain growth spurt, a period of rapid brain growth, during which many neurons morphologically mature by extending neurites and forming synaptic connections. Why developing neurons are particularly vulnerable to alcohol during the brain growth spurt is unknown, but may be due to an interaction between alcohol and patterns of gene expression regulating neuronal morphological development. MicroRNAs are small, non-coding RNAs that regulate the development of the central nervous system by controlling the expression of many genes. Two microRNAs of particular importance to brain development are microRNA-132 (miR-132) and miR-124, both of which are enriched in brain and regulate neuronal morphogenesis and neurite outgrowth. The central hypothesis of this proposal is that alcohol disrupts neuronal maturation and renders neurons vulnerable to alcohol toxicity by interfering with miR-132 and miR-124 expression. Thus, the experiments of this proposal will focus on the interaction between alcohol and these microRNAs during brain development. In this proposal, we will determine whether miR-132 and miR-124 expression are developmentally regulated, whether their expression levels are related to periods of alcohol vulnerability, and whether alcohol affects their expression. We will also determine whether experimental manipulations of miR-132 and miR-124 alter neuronal morphology and vulnerability to alcohol. We will determine whether ectopic expression of these microRNAs promotes neurite outgrowth and protects developing neurons against alcohol toxicity. Conversely, we will determine whether silencing of miR-132 and miR-124 impairs neurite outgrowth and increases the vulnerability of developing neurons to alcohol-induced cell death. Thus, these studies will examine the effect of alcohol on two related and important microRNAs and determine their role in maturation-dependent alcohol resistance, a phenomenon of fundamental importance in FAS. PUBLIC HEALTH RELEVANCE: Alcohol abuse during pregnancy can profoundly affect the developing fetus, resulting in fetal alcohol syndrome (FAS). Alcohol damages the developing brain, leading to microencephaly, mental retardation, and hyperactivity. In this proposal we will examine the effect of alcohol on microRNAs, master switches that control the expression of several genes involved in the morphological maturation of neurons.