Transcriptional regulation of oxidative death

氧化死亡的转录调控

• 批准号: 7553885
• 负责人: Rajiv R Ratan
• 金额: $ 20.8万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7553885
• 关键词: Huntington' s disease; amidohydrolases; apoptosis; brain disorder chemotherapy; cAMP response element binding protein; cerebral cortex; clinical research; corpus striatum; enzyme inhibitors; gel mobility shift assay; gene expression; gene mutation; genetic regulation; genetic transcription; immunoprecipitation; laboratory rat; mithramycin; nerve /myelin protein; neuroprotectants; neuroregulation; oxidative stress; pathologic process; protein structure; tissue /cell culture; transfection /expression vector

Huntington's Disease (HD) is an autosomal dominant disorder resulting from selective loss of neurons in the striatum and cerebral cortex. Loss of neurons in HD results from pathological expansion of CAG repeats encoding glutamine. Though the precise mechanisms by which glutamine repeats lead to neuronal loss in HD are unclear, oxidative stress, apoptosis, and transcriptional dysregulation have all been implicated in disease pathogenesis. To understand better oxidative and transcriptional mechanisms that may lead to neuronal loss in HD, we have utilized an in vitro model of oxidative stress in primary cortical neurons. In preliminary studies we have shown that oxidative cell death can be fully abrogated by sequence-selective DNA binding drugs, including mithramycin A (MMA) and chromomcyin A3. These agents are members of the aureolic acid antitumor antibiotics that share a common chromophore, aglycon ring, but differ in the nature of the sugar moieties connected to either side of the aglycone ring. Both antibiotics inhibit transcription during macromoleclar biosynthesis by binding to the "GC" rich transcriptional response elements. To test whether aureolic antibiotics can protect neurons in an in vivo model ofneurodegeneration that may inolve oxidative stress, we examined the effect of MMA in the R6/2 transgenic model of HD. We found that MMA prolongs survival in these mice by nearly 30%, a magnitude superior to any other single neuroprotective agent. These preliminary data are consistent with the overall hypothesis to be tested in this proposal: MMA inhibits neuronal death due to oxidative stress and/or mutant Huntington protein in vitro and in vivo by inhibiting the binding of pro-apoptotic zinc finger transcription factors such as TIEG, and enhancing the DNA binding of pro-survival transcription factors such as CREB. We will examine this hypothesis by determining whether protective concentrations of MMA inhibit TIEG binding to its GC rich DNA binding sites and whether TIEG is critical for oxidative death in cortical neurons. In the second aim, we will determine how MMA affects CREB DNA binding and whether increases in CREB DNA binding contribute to MMA's salutary effects. In the last specific aim, we will compare the mechanism of neuroprotection of MMA to those ofhistone deacetylase inhibitors, another class of transcriptional regulators. These studies will provide critical, mechanistic data on neuroprotective modulators of transcription.

亨廷顿氏病（HD）是一种常染色体显性疾病，是由于纹状体和脑皮质中神经元的选择性丧失而引起的。 HD中神经元的丧失是由编码谷氨酰胺的CAG重复的病理扩张引起的。 尽管谷氨酰胺重复的确切机制导致HD神经元丧失尚不清楚，但氧化应激，凋亡和转录失调都与疾病发病机理有关。为了理解可能导致HD神经元丧失的更好氧化和转录机制，我们在原代皮质神经元中使用了氧化应激的体外模型。在初步研究中，我们已经表明，氧化细胞死亡可以通过序列选择性DNA结合药物（包括毛霉素A（MMA）和染色体A3）完全消除。这些药物是具有共同发色团敏感环但 连接到良性环的两侧的糖部分的性质不同。两种抗生素都通过与“ GC”丰富的转录响应元件结合来抑制大分子生物合成过程中的转录。为了测试金黄色抗生素是否可以在可能会影响氧化应激的体内模型中保护神经元，我们检查了MMA在HD的R6/2转基因模型中的作用。我们发现，MMA在这些小鼠中延长了近30％的生存率，这是比任何其他单一神经保护剂高的级级。 These preliminary data are consistent with the overall hypothesis to be tested in this proposal: MMA inhibits neuronal death due to oxidative stress and/or mutant Huntington protein in vitro and in vivo by inhibiting the binding of pro-apoptotic zinc finger transcription factors such as TIEG, and enhancing the DNA binding of pro-survival transcription factors such as CREB.我们将通过确定MMA的保护浓度是否抑制扎根来检查这一假设 与其富含GC的DNA结合位点结合，以及绑带对于皮质神经元中的氧化死亡至关重要。在第二个目标中，我们将确定MMA如何影响CREB ​​DNA结合，以及CREB ​​DNA结合的增加是否有助于MMA的有益作用。在最后一个特定目的中，我们将比较MMA神经保护的机理与组蛋白脱乙酰基酶抑制剂，另一种转录调节剂。这些研究将提供有关转录神经保护调节剂的关键机械数据。