Sphingolipids in Ethanol-Induced Neuronal Apoptosis

产前酒精暴露会诱发一系列被称为胎儿酒精谱系障碍（FASD）的疾病。产前酒精暴露最严重的后果之一是对发育中的大脑造成损害。乙醇引发新生啮齿动物大脑在快速突触发生期间的凋亡性神经变性，这与人类大脑在怀孕的最后三个月和出生后几年的发育相对应。乙醇诱导的新生啮齿动物神经元丢失可能解释了FASD中观察到的一些神经病理状况。然而，在发育中的啮齿动物大脑中，乙醇诱导神经元丢失的机制尚不完全清楚。阐明这些机制将有助于FASD治疗应用的发展。本研究旨在阐明乙醇诱导的神经元丢失机制，使用出生后第7天（P7） C57BLl6小鼠的大脑，这些小鼠在急性暴露于乙醇后表现出强烈的凋亡性神经变性。我们之前的研究表明，乙醇影响脑脂质代谢和信号转导途径。具体来说，我们已经证明乙醇诱导神经酰胺（细胞凋亡的介质）升高，乙醇诱导amp激活的蛋白激酶（AMPK）途径和磷酸肌醇3-激酶(PI3K)/Akt途径（生存途径）的扰动。在这项应用中，我们提出验证我们的假设，即乙醇诱导的脂质改变（特别是神经酰胺升高）与乙醇诱导的AMPK和P13K1Akt通路的扰动一起触发或增强发育中的脑细胞凋亡。在Aim 1中，将检查受乙醇影响的鞘脂的细胞和亚细胞定位的变化，因为这将深入了解这些脂质的作用。在Aim 2中，将寻找乙醇诱导的神经酰胺升高的酶和调节因子，并研究抑制神经酰胺升高对乙醇诱导的细胞凋亡的影响。这些研究将揭示鞘脂在乙醇诱导的脑细胞凋亡中的作用，并为未来FASD的治疗策略提供依据。

Prenatal alcohol exposure induces a range of disorders called fetal alcohol spectrum disorders (FASD). One of the most severe consequences of prenatal alcohol exposure is the damage to the developing brain. Ethanol triggers apoptotic neurodegeneration in the newborn rodent brain during the period of rapid synaptogenesis that corresponds to human brain development during the last trimester of pregnancy and for several years after birth. The ethanol-induced neuronal loss in newborn rodents is likely to explain some of the neuropathological conditions observed in FASD. However, mechanisms of ethanol-induced neuronal loss in the developing rodent brain are not fully understood. Elucidation of these mechanisms would contribute to the development of therapeutic applications for FASD. This proposal is aimed at elucidating the mechanisms of ethanol-induced neuronal loss using the brains of postnatal day 7 (P7) C57BLl6 mice, which show robust apoptotic neurodegeneration upon acute exposure to ethanol. Our previous studies indicate that ethanol affects brain lipid metabolism and signal transduction pathways. Specifically, we have shown ethanol-induced elevation in ceramide (a mediator of apoptosis) and ethanol-induced perturbation of the AMP-activated protein kinase (AMPK) pathway and the phosphoinositol 3-kinase (PI3K)/Akt pathway (a survival pathway). In this application, we propose to test our hypothesis that ethanol-induced lipid alteration-specifically ceramide elevationtriggers or enhances apoptosis in the developing brain in concert with ethanol-induced perturbation of the AMPK and P13K1Akt pathway. In Aim 1, changes in the cellular and subcellular localization of sphingolipids affected by ethanol will be examined because this would give insight into the roles of these lipids. In Aim 2, enzymes and regulators responsible for ethanol-induced ceramide elevation will be sought, and the effects of the inhibition of ceramide elevation on ethanol-induced apoptosis will be examined. These studies will reveal the functions of sphingolipids in ethanol-induced apoptosis in the developing brain, and will offer bases for future therapeutic strategies for FASD.