Consequence of RNA oxidation

描述（由申请人提供）：胞质RNA氧化是阿尔茨海默病（AD）患者大脑易损神经元的一个突出特征。然而，RNA氧化在AD发病机制中的作用尚不清楚。我们最近开发了一种新的方法来分离和表征氧化RNA。我们发现高达50%的聚(A)+ mrna在AD大脑中被氧化。氧化mRNA种类的鉴定表明，一些mRNA更容易受到氧化损伤；因此，RNA氧化不是随机的，而是高度选择性的。重要的是，许多已确定的氧化mRNA物种与AD的发病机制有关。对氧化损伤mRNA后果的研究表明，氧化的mRNA不能正确翻译，导致蛋白质表达减少，从而失去正常的蛋白质功能。值得注意的是，将氧化mrna微注射到神经元细胞中会导致细胞死亡，这表明RNA氧化增加可能导致细胞死亡。此外，一些证据表明，RNA氧化是细胞死亡之前的早期事件，而不是垂死细胞的人工产物。综上所述，在神经退行性变过程中，RNA氧化本身与神经元退化直接相关，而不是无害的副现象。这是一个重要但尚未得到充分研究的领域。需要进一步的详细调查。我们假设mRNA的氧化损伤可能导致蛋白质功能障碍，这可能导致AD的神经元死亡。在Aim 1中，我们建议通过cDNA芯片进一步鉴定氧化mRNA种类，量化每种氧化mRNA的氧化水平，并研究AD中所鉴定的氧化mRNA种类对应的蛋白质。本研究将鉴定这些高氧化mRNA物种，并确定这些高氧化mRNA物种对应的蛋白质是否存在缺陷。在目标2中，我们建议研究RNA氧化的生物学后果。这些研究将阐明RNA氧化是否在AD的发病机制中起作用。

DESCRIPTION (provided by applicant): Cytoplasmic RNA oxidation is a prominent feature of vulnerable neurons in the brains of Alzheimer's disease (AD) patients. However, the role of RNA oxidation in the pathogenesis of AD is still unknown. We have recently developed a novel procedure to isolate and characterize oxidized RNA. We found that up to 50% of poly(A)+ mRNAs are oxidized in AD brains. Identification of oxidized mRNA species revealed that some mRNAs are more susceptible to oxidative damage; thus, RNA oxidation is not random but highly selective. Importantly, many identified oxidized mRNA species have been implicated in the pathogenesis of AD. Investigation of the consequence of oxidatively damaged mRNAs revealed that oxidized mRNA could not be translated properly leading to reduced protein expression and consequently, loss of normal protein function. Significantly, microinjection of oxidized mRNAs into neuronal cells leads to cell death, suggesting that increased RNA oxidation could lead to cell death. Furthermore, several lines of evidence suggest that RNA oxidation is an early event preceding cell death, not an artifact of dying cells. Taken these studies together, RNA oxidation itself is directly associated with neuronal deterioration instead of harmless epiphenomenona during the process of neurodegeneration. This is an important, yet understudied area. Further detailed investigation is needed. We hypothesize that oxidative damage to mRNA could result in protein malfunction, which could contribute to neuronal death in AD. In Aim 1, we propose to further identify oxidized mRNA species by cDNA microarray, to quantify the oxidation level for each oxidized mRNAs, and to investigate the proteins corresponding to the identified oxidized mRNA species in AD. This study will identify those highly oxidized mRNA species and determine whether proteins corresponding to those highly oxidized mRNA species are defective. In Aim 2, we propose to investigate the biological consequence of RNA oxidation. These studies will elucidate whether RNA oxidation plays a role in the pathogenesis of AD.