Aging and brain 5-lipoxygenase

描述（由申请人提供）：表观遗传机制，包括DNA甲基化和组蛋白修饰深刻影响基因表达，也似乎在衰老中改变。更好地了解大脑中的这些机制可能会为治疗/预防与衰老相关的中枢神经系统病变提供新的靶点。在过去四年的资助中，该实验室的研究已经确定，大脑中5-脂氧合酶（5-LOX）的表达，一种炎症酶，在衰老过程中增加，受到谷氨酸受体激活和糖皮质激素的刺激，可能与神经退行性疾病有关，可能在阿尔茨海默病（AD）中。其他人已经表明，5-LOX敲除在阿尔茨海默病的小鼠模型Tg 2576小鼠中，并减少淀粉样变性。最近的初步数据表明，神经元5-LOX表达在5-LOX启动子中CpG岛的甲基化状态改变后增加（例如，通过低甲基化药物5-氮杂-2 ′-脱氧胞苷）或在改变组蛋白乙酰化后（例如，通过组蛋白脱乙酰酶-HDAC-抑制剂）。在这个建议中，我们假设，表观遗传机制改变了老化的脑神经元，并负责脑5-LOX表达的调节; 5-LOX表达是由5-LOX启动子甲基化降低和/或改变组蛋白乙酰化和甲基化在5-LOX基因。我们提出了以下三个具体的目标：1）在小鼠中研究衰老对a）脑DNMT 1和HDAC表达，B）脑区域特异性5-LOX启动子甲基化，和c）5-LOX相关的组蛋白乙酰化和甲基化的影响; 2）在原代神经元培养物中，测试细胞成熟/老化对神经元DNMT 1和HDAC表达、5-LOX启动子甲基化、和5-LOX相关的组蛋白乙酰化和甲基化;和3）使用原代神经元培养物，研究DNMT 1和HDAC抑制/敲低在5-LOX表达中的作用。这项资助提案中概述的研究旨在提供相关数据来支持我们的假设，即表观遗传神经元改变是一个假定的因素，使衰老的大脑倾向于显示5-LOX基因表达上调。拟议的实验可能会证实这一假设，即表观遗传机制参与脑老化。

DESCRIPTION (provided by applicant): Epigenetic mechanisms that include DNA methylation and histone modifications profoundly influence gene expression and also appear to be altered in aging. A better understanding of these mechanisms in the brain may point to novel targets for the therapy/prevention of aging-associated central nervous system pathologies. Over the last four years of funding, studies from this laboratory have established that the brain expression of 5-lipoxygenase (5-LOX), an inflammatory enzyme, increases during aging, is stimulated by glutamate receptor activation and by glucocorticoids, and might be associated with neurodegeneration, possibly in Alzheimer's disease (AD). Others have shown that 5-LOX knockout in a mouse model of Alzheimer's disease, the Tg2576 mouse, and decreases amyloidosis. Recent preliminary data indicate that neuronal 5-LOX expression increases following changes in the methylation state of CpG islands in 5-LOX promoter (e.g., by a hypomethylating drug 5-aza-2'-deoxycytidine) or after altered histone acetylation (e.g., by histone deacetylases - HDACs - inhibitors). In this proposal, we hypothesize that epigenetic mechanisms are altered in aging brain neurons and are responsible for the regulation of brain 5-LOX expression; 5-LOX expression is triggered by decreased methylation at the 5-LOX promoter and/or altered histone acetylation and methylation at the 5-LOX gene. We propose the following three specific AIMs: 1) Investigate in mice the effects of aging on a) brain DNMT1 and HDACs expression, b) brain region-specific 5-LOX promoter methylation, and c) 5-LOX-related histone acetylation and methylation; 2) In primary neuronal cultures, test the in-vitro effects of cell maturation/aging on neuronal DNMT1 and HDACs expression, 5-LOX promoter methylation, and 5-LOX-related histone acetylation and methylation; and 3) Using primary neuronal cultures, investigate the role of DNMT1 and HDACs inhibition/knockdown in 5-LOX expression. The research outlined in this grant proposal is designed to provide relevant data in support of our hypothesis that an epigenetic neuronal alteration is a putative factor that predisposes the aging brain to display an upregulated expression of the 5-LOX gene. The proposed experiments may corroborate the hypothesis that epigenetic mechanisms are involved in brain aging.