Regulation of Neuroprotective Lipid Sgnals by Spatially Distinct NMDA Receptors

描述(由申请人提供)： 这项拟议的研究是一项长期努力的一部分，目的是了解脂质信号机制如何决定受表现出兴奋性毒性细胞死亡的疾病影响的脑细胞的命运。刺激突触NMDA受体促进神经元存活，而刺激突触外NMDA受体导致主导的促死亡信号。然而，决定这两种结果的分子途径并不完全清楚。两个主要不重叠的基因表达程序分别介导细胞生存和细胞死亡，分别由来自这些空间上不同的NMDA受体亚群的信号诱导。神经保护因子1(NPD1)是一种来源于二十二碳六烯酸(DMA)的立体特异性脂质介质，可激活人脑和视网膜细胞中有利于生存的基因表达程序。NPD1是否介导突触NMDA受体的促生存信号？通过原代培养的海马细胞研究突触和突触外NMDA受体对NPD1生物利用度的控制。实验将集中在脑源性神经营养因子(BDNF)对NPD1池大小的调节，BDNF是突触NMDA受体促生存信号的中介，也是合成NPD1的已知激动剂。实验将使用细胞和分子生物学和生物化学的技术，基于高效液相-电喷雾串联质谱仪的脂组分析，以及使用15-脂氧合酶-1(15-LOX-1)缺陷小鼠，这些小鼠不能合成NPD1。这项研究的结果将证明，突触NMDA受体的促生存信号是通过增加BDNF的表达来增加NPD1池的大小来介导的。此外，缺乏15-LOX-1的神经元培养细胞将被证明比野生型培养细胞更容易受到兴奋毒性损伤，在体外和体内，NPD1将被证明可以减轻兴奋毒性损伤。

DESCRIPTION (provided by applicant): The proposed research is part of a long-term effort to understand how lipid signaling mechanisms determine the fate of brain cells affected by diseases which exhibit excitotoxic cell death. Stimulation of synaptic NMDA receptors promotes neuronal survival, while stimulation of extrasynaptic NMDA receptors leads to dominant, pro-death signaling. However, the molecular pathways that determine these two outcomes are not fully understood. Two largely non-overlapping gene expression programs mediating cell survival and cell death, respectively, are induced by signaling from these spatially distinct NMDA receptor subpopulations. Neuroprotection D1 (NPD1) is a stereospecific lipid mediator derived from docosahexaenoic acid (DMA) that activates a pro-survival gene expression program in human brain and retinal cells. Does NPD1 mediate pro- survival signals from synaptic NMDA receptors? Control of NPD1 bioavailability by synaptic and extrasynaptic NMDA receptors will be investigated using primary hippocampal cell cultures. Experiments will focus on NPD1 pool size regulation by brain-derived neurotrophic factor (BDNF), which is a mediator of pro- survival signaling from synaptic NMDA receptors and a known agonist of NPD1 synthesis. Experiments will employ techniques from cell and molecular biology and biochemistry, HPLC-ESI tandem mass spectrometry-based lipidomic analysis, and the use of 15-lipoxygenase-1 (15-LOX-1) deficient mice, which are incapable of NPD1 synthesis. The results of the proposed studies will demonstrate that pro-survival signaling from the synaptic NMDA receptor is mediated through enhancement of the NPD1 pool size via increased expression of BDNF. Additionally, 15-LOX-1 deficient neuronal cultures will be shown to be significantly more vulnerable to excitotoxic injury than wild type cultures, and NPD1 will be shown to attenuate excitotoxic injury in vitro and in vivo.