Project III- Impact of Hypoxia-Ischemia and/or Inflammation on Lipid Rafts in Cerebellum

在足月新生儿(相当于出生后10天的大鼠)，小脑容易受到 缺氧-缺血。在这段时间里，小脑正在发生迅速的变化：小脑 浦肯野神经元、小脑深部核神经元和小脑颗粒细胞迅速增殖， 轴突延长，小脑小胶质细胞数量增多。我们的实验室专注于研究脂质 小脑和其他主要病灶的神经发育障碍的移植物功能和功能障碍 关于酒精，胎儿酒精谱系障碍的致病因素。脂筏是细胞的动态微域 调节信号转导和蛋白质运输的质膜。缺氧/缺血(H/I)可能 引起信号变化或产生活性氧(ROS)。ROS可能导致脂质氧化 从而导致脂筏功能障碍。这些变化可导致长期的小脑发育改变。 对小脑功能的影响。L1细胞黏附分子(L1)--大脑的关键分子 Toll样受体TLR4可作为小脑脂筏功能的报告基因 颗粒神经元(CGN)、浦肯野神经元(PN)、小脑深核神经元(DCN)和小脑 小胶质细胞。胆碱--磷脂酰胆碱(PtdCho)和鞘磷脂的重要营养物质和前体 (SM)在脂筏调节中都很重要，可改善脂筏功能和酒精后的行为 曝光。我们使用PN7大鼠的初步数据显示，在以下情况下，皮质中的脂筏功能障碍 H/I和胆碱/GM1神经节苷脂部分地阻止了这种作用。此外，补充胆碱 保护L1信号、脂筏分布和小脑调节行为不受其他因素的影响 神经毒药。我们的假设是PN10的H/I导致CGN、PN、DCN和 小胶质细胞导致小脑功能低下。由内毒素引起的炎症协同作用增加了这种 功能障碍，降温、胆碱和/或头孢曲松将部分改善这些影响。我们将使用 PN10大鼠幼鼠(相当于术语)和H/I的改进的Rice-Vanucci模型。我们的三个具体目标是：1) 或测定缺氧缺血后小脑全脑及CGN、PN和DCN的脂筏功能和组成 2)测定小脑小胶质细胞的脂筏功能和组成 H/I后伴有或不伴有先前的内毒素引起的炎症；3)确定低温、胆碱和/或 头孢曲松可改善1)H/I和H/I后脂筏功能和成分的急性变化。 小脑、CGN、PN、DCN和小胶质细胞的早期炎症；2)H/I伴或不伴炎症的影响 关于小脑相关行为的研究。我们的首要目标是减少与H/I相关的发病率 新生儿。

In the term newborn (equivalent to the postnatal day (PN) 10 rat), the cerebellum is vulnerable to the effects of hypoxia-ischemia. During this period of time, rapid change in the cerebellum is taking place: the cerebellar Purkinje neurons, the deep cerebellar nuclear neurons and the cerebellar granule cells are rapidly proliferating, and extending their axons and the numbers of cerebellar microglia are increasing. Our lab is focused on lipid raft function and dysfunction in the cerebellum and in other neurodevelopmental disorders with a primary focus on ethanol, the causative agent of fetal alcohol spectrum disorder. Lipid rafts are dynamic microdomains of the plasma membrane which regulate signal transduction and protein trafficking. Hypoxia/ischemia (H/I) may cause alterations in signaling or generate reactive oxygen species (ROS). ROS may cause oxidation of lipids and therefore lipid raft dysfunction. These changes can lead to altered cerebellar development with long term consequences for cerebellar function. L1 cell adhesion molecule (L1), a molecule critical for brain development, and the toll like receptor, TLR4, can be used as reporters for lipid raft function in cerebellar granule neurons (CGN), Purkinje neurons (PN), deep cerebellar nuclear neurons (DCN) and cerebellar microglia. Choline, an essential nutrient and precursor to phosphatidylcholine (PtdCho) and sphingomyelin (SM), both important in lipid raft regulation, improves lipid raft function and behavior following alcohol exposure. Our preliminary data using PN7 rats shows that lipid rafts are dysfunctional in the cortex following H/I and that choline/GM1 ganglioside partially prevents this effect. In addition, choline supplementation protects L1 signaling, lipid raft distribution and cerebellar mediated behavior from the effects of other neurotoxicants. Our hypothesis is that H/I at PN10 causes lipid raft dysfunction in CGN, PN, DCN and microglia leading to poor cerebellar function. Inflammation caused by LPS synergistically increases this dysfunction, and hypothermia, choline, and/or ceftriaxone will partially ameliorate these effects. We will use PN10 rat pups (term equivalent) and the modified Rice-Vanucci model of H/I. Our three specific aims are: 1) Determine lipid raft function and composition in whole cerebellum and CGN, PN and DCN following H/I with or without prior LPS induced inflammation; 2) Determine lipid raft function and composition in cerebellar microglia following H/I with or without prior LPS induced inflammation; 3) Determine if hypothermia, choline, and/or ceftriaxone ameliorates 1) the acute alterations in function and composition of lipid rafts after H/I and H/I with prior inflammation in cerebellum, CGN, PN, DCN and microglia; 2) effects of H/I with or without inflammation on cerebellar related behaviors. Our overarching goal is to reduce the morbidity associated with H/I in neonates.