Mechanisms of ethanol-induced neurodevelopmental effects

乙醇诱导神经发育效应的机制

• 批准号: 7690393
• 负责人: Marina Guizzetti
• 金额: $ 31.01万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-25 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7690393
• 关键词: Address; Affect; Alcohols; Alzheimer' s Disease; Apolipoprotein E; Apolipoproteins; Astrocytes; Atherosclerosis; Binding; Brain; Brain Injuries; Calories; Cell Proliferation; Cells; Cholesterol; Cholesterol Homeostasis; Coculture Techniques; Conditioned Culture Media; Congenital Abnormality; Country; Cultured Cells; Development; Developmental Neurotoxicity of Ethanol; Diet; Employee Strikes; Ethanol; Event; Exposure to; Fetal Alcohol Exposure; Fetal Alcohol Syndrome; Fetal Development; Fetus; Foundations; Gel Chromatography; Generations; Genetic Transcription; Guidelines; Homeostasis; Immunohistochemistry; In Vitro; Inborn Genetic Diseases; Incubated; Injury; Investigation; Lead; Lipids; Lipoproteins; Liquid substance; Malnutrition; Mediating; Membrane; Membrane Microdomains; Mental Retardation; Microcephaly; Mutation; NIH Program Announcements; Neocortex; Neuraxis; Neurites; Neurons; Phospholipase D; Phospholipids; Play; Population; Pregnancy; Pregnant Women; Prevalence; Production; Proteins; Rattus; Research Personnel; Risk; Role; Signal Transduction Pathway; Small Interfering RNA; Smith-Lemli-Opitz Syndrome; Sonic Hedgehog Pathway; South Africa; System; Testing; Tissues; Up-Regulation; alcohol effect; cholesterol biosynthesis; cholesterol trafficking; cholesterol transporters; experience; feeding; in vivo; in vivo Model; lipoprotein cholesterol; neuron development; neurotrophic factor; novel; pregnant; public health relevance; research study; response; synaptogenesis

DESCRIPTION (provided by applicant): This proposal will address a novel aspect of ethanol's developmental neurotoxicity, i.e. its effect on cholesterol homeostasis in the central nervous system. While too much cholesterol may be deleterious, as in case of atherosclerosis and Alzheimer's disease, too little can produce birth defects. Different degrees of mental retardation are often observed in inborn errors of cholesterol synthesis such as Smith-Lemli-Opitz syndrome. Lack of cholesterol during brain development as a consequence of these genetic defects leads to severe brain damage, including microcephaly and mental retardation, both of which are hallmarks of the fetal alcohol syndrome. The effects of ethanol on cholesterol homeostasis in the developing brain have not been investigated. In the brain, cholesterol is mostly produced endogenously, and its homeostasis is regulated by endogenously produced lipoproteins and cholesterol transporters. This proposal will investigate the hypothesis that ethanol, by upregulating cholesterol transporters and lipoprotein production by central nervous system cells, will increase the clearance of cholesterol from the brain, causing cholesterol depletion. Low levels of cholesterol are consistent with some of the effects caused by in utero alcohol exposure such as inhibition of the sonic hedgehog pathway, neuronal development and survival, and cell proliferation. Specific Aims of the proposal are: 1) The investigation of the role of ABCA1 and ABCG1 in ethanol-induced cholesterol efflux. The effect of ethanol on cholesterol efflux and cholesterol levels will be investigated in cortical neurons in vitro; in addition, the role of ABCA1, ABCG1, and phospholipase D in ethanol-induced upregulation of cholesterol efflux and cholesterol transporter induction in astrocytes and, possibly, in neurons will be examined by selectively removing these proteins form astrocyte and neuron cultures. 2) The investigation of the effect of ethanol on astrocyte-generated lipoproteins and their interaction with neurons. The effect of ethanol on the composition of astrocyte-produced lipoproteins separated by gel filtration, and their role on cholesterol efflux from neurons will be analyzed. Furthermore, the effect of ethanol on lipoprotein composition and cholesterol efflux will be examined in an astrocyte/neuron co- culture system. 3) The investigation of the effect of in vivo ethanol administration on ABC cholesterol transporters and on cholesterol levels in the developing brain. The effect of in vivo exposure to ethanol during gestation on the cholesterol transporters ABCA1 and ABCG1 transcription and expression in neurons and astrocytes and on cholesterol levels will be assessed in the neocortex of rat fetuses at gestational day 21. Altogether, these studies are directed at characterizing a possible novel mechanism involved in ethanol-induced neurodevelopmental effects, i.e. its effects on cholesterol homeostasis in the brain. PUBLIC HEALTH RELEVANCE The proposed studies on the effect of ethanol on cholesterol homeostasis in the developing brain were prompted by the observation that several of the neurodevelopmental effects caused by ethanol are consistent with effects caused by lack of cholesterol. Cholesterol is indeed necessary for various aspects of brain development. We hypothesized that ethanol, by mechanisms to be investigated in the proposed project, may affect cholesterol homoeostasis and reduce cholesterol levels in the developing brain. The most recent discoveries in the field of cholesterol trafficking will be applied to the investigation of the effects of ethanol on cholesterol transporters, lipoprotein generation and, ultimately, cholesterol levels in the developing brain. As cholesterol is a regular component of the diet, our studies could potentially lead to the revision of dietary guidelines for pregnant women at risk. It may also help understanding why in some very poor regions of South Africa the prevalence of FAS is much higher than in Western countries as these populations also experience severe malnutrition.

描述（由申请人提供）：该提案将解决乙醇发育神经毒性的新方面，即其对中枢神经系统中胆固醇稳态的影响。尽管过多的胆固醇可能是有害的，就像动脉粥样硬化和阿尔茨海默氏病一样，太少会产生先天缺陷。经常在胆固醇合成的先天误差（例如史密斯 - 莱姆利 - 奥皮兹综合征）中观察到不同程度的智力低下。由于这些遗传缺陷，在大脑发育过程中缺乏胆固醇会导致严重的脑损伤，包括小头畸形和智力低下，这两者都是胎儿酒精综合征的标志。尚未研究乙醇对发育中大脑中胆固醇稳态的影响。在大脑中，胆固醇主要是内源性产生的，其稳态受到内源产生的脂蛋白和胆固醇转运蛋白的调节。该提议将调查以下假设：乙醇通过中枢神经系统细胞上调胆固醇转运蛋白和脂蛋白的产生，将增加大脑胆固醇的清除，从而导致胆固醇消耗。低水平的胆固醇与子宫酒精暴露在诸如抑制声音刺猬途径，神经元发育和生存以及细胞增殖等的某些影响一致。该提案的具体目的是：1）研究ABCA1和ABCG1在乙醇诱导的胆固醇外排的作用。乙醇对胆固醇外排和胆固醇水平的影响将在体外的皮质神经元中研究；此外，ABCA1，ABCG1和磷脂酶D在乙醇诱导的星形胶质细胞中胆固醇外排和胆固醇转运蛋白诱导的上调中的作用，在神经元中可能会通过选择性地去除这些蛋白质形成星形胶质细胞和神经元培养物来检查神经元中。 2）研究乙醇对星形胶质细胞生成的脂蛋白的影响及其与神经元的相互作用。将分析乙醇对由凝胶过滤分离的星形胶质细胞产生的脂蛋白组成的作用，将分析它们对神经元胆固醇外排的作用。此外，将在星形胶质细胞/神经元共培养系统中检查乙醇对脂蛋白组成和胆固醇外排的影响。 3）研究体内乙醇对ABC胆固醇转运蛋白以及发育中大脑中胆固醇水平的影响。妊娠期间体内暴露于乙醇对胆固醇转运蛋白转运蛋白转运蛋白和ABCG1转录以及在神经元和星形胶质细胞以及胆固醇水平上的转录和表达的影响，将在妊娠天大鼠胎儿的新皮层进行评估。大脑中的胆固醇稳态。公共卫生相关性关于乙醇对发育中大脑中胆固醇稳态影响的拟议研究是由观察到的，即乙醇引起的几种神经发育作用与缺乏胆固醇引起的作用一致。胆固醇确实是大脑发育的各个方面所必需的。我们假设乙醇通过在拟议的项目中进行研究的机制可能会影响胆固醇的同源性，并降低发育中的大脑中的胆固醇水平。胆固醇运输领域的最新发现将用于研究乙醇对胆固醇转运蛋白，脂蛋白产生以及最终在发育中的大脑中的胆固醇水平的影响。由于胆固醇是饮食的常规组成部分，因此我们的研究可能会导致修订有风险的孕妇饮食指南。这也可能有助于理解为什么在南非一些非常贫穷的地区，FAS的流行率远高于西方国家，因为这些人口也经历了严重的营养不良。