Estrogenic Regulation of Mitochondrial Transcription in HD

HD 中线粒体转录的雌激素调节

• 批准号: 7091365
• 负责人: HOON RYU
• 金额: $ 25.61万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-15 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7091365
• 关键词: DNA footprinting; Huntington' s disease; apoptosis; cAMP response element binding protein; cell death; electron microscopy; estrogen receptors; gel mobility shift assay; genetic regulatory element; genetic transcription; genetically modified animals; hormone regulation /control mechanism; immunoprecipitation; laboratory mouse; light microscopy; longitudinal animal study; mitochondrial disease /disorder; neurochemistry; oxidative stress; phosphorylation; polymerase chain reaction; protein kinase A; receptor expression; small interfering RNA; western blottings

DESCRIPTION (provided by applicant): While the role of mitochondrial dysfunction has been proposed in neurodegenerative diseases, the exact mechanism of mitochondrial pathogenesis is unclear. Our preliminary studies show that hormone receptors, estrogen receptors (ERs), and cAMP response elements binding protein (CREB) are present in the mitochondrial matrix of neurons. CREB directly binds to cAMP response elements (CREs) in the promoter regions (D-loop) of mitochondrial DNA. We also show that CREB is transcriptionally active in mitochondria and hypothesize that the regulation of mitochondrial gene expression by mitochondrial CREB may underlie some of the established protective effects in neuronal survival. This data implies that mitochondrial localization of ERs and CREB could be regulated by novel signaling pathways in the intact central nervous system and that their functions in the mitochondria might be important in neuronal survival. Therefore, we propose that the levels and activities of mitochondrial hormone receptors and transcription factors, which induce mitochondrial gene transactivation, may contribute to mitochondrial dysfunction and the subsequent neuronal loss observed in Huntington's disease (HD). Thus, the specific aims of our proposed study are: 1) To identify the topographic brain distribution of mitochondrial ERs and characterize mitochondrial estrogen receptor element (ERE) sites and interaction with CREB in neurons. 2) To determine the regulatory mechanism of mitochondrial ERs and CREB-mediated mitochondrial transcription. Protein Kinase A (PKA) is a well known enzyme for activation of ERs and phosphorylating CREB at Ser133. In this context, we propose that PKA localizes into the mitochondrial matrix and that mitochondrial PKA activity may play a role in the phosphorylation and transactivation of mitochondrial ERs and CREB. We will further characterize mitochondrial ER, PKA, and CREB activity in mouse models of HD. 3) To develop therapeutic approaches to target mitochondrial ERs and CREB in vitro and in vivo in transgenic and Knock-in HD mice expressing short segment and full length mutant huntingtin. We will determine whether specific estrogen receptor modulators (SERMs) augment mitochondrial PKA activity and mitochondrial ER and CREB phosphorylation to induce mitochondrial gene transcription that influences neuronal survival. These studies will provide novel mechanisms for preventing mitochondrial transcriptional dysfunction and help in the design of applicable compounds that modulate mitochondrial function.

描述（由申请人提供）：虽然已经提出了线粒体功能障碍的作用在神经退行性疾病中，但线粒体发病机理的确切机制尚不清楚。我们的初步研究表明，神经元的线粒体基质中存在激素受体，雌激素受体（ERS）和CAMP反应元件结合蛋白（CREB）。 CREB直接与线粒体DNA的启动子区域（D-LOOP）中的cAMP响应元件（CRE）结合。我们还表明，CREB在线粒体中具有转录活性，并假设通过线粒体CREB调节线粒体基因表达可能是神经元存活中一些已建立的保护作用的基础。该数据表明，ERS和CREB的线粒体定位可以通过完整的中枢神经系统中的新信号通路来调节，并且它们在线粒体中的功能可能在神经元存活中很重要。因此，我们提出，诱导线粒体基因反式激活的线粒体激素受体和转录因子的水平和活性可能导致线粒体功能障碍以及随后在亨廷顿氏病（HD）中观察到的神经元丧失。因此，我们提出的研究的具体目的是：1）确定线粒体ER的地形脑分布并表征线粒体雌激素受体元件（ERE）位点以及与神经元中CREB的相互作用。 2）确定线粒体ER和CREB介导的线粒体转录的调节机制。蛋白激酶A（PKA）是一种在Ser133处激活ER和磷酸化CREB的众所周知的酶。在这种情况下，我们建议PKA定位于线粒体基质中，线粒体PKA活性可能在线粒体ER和CREB的磷酸化和反式激活中起作用。我们将进一步表征HD小鼠模型中的线粒体ER，PKA和CREB活性。 3）在体外和体内靶向线粒体ER和CREB的治疗方法，并在转基因和敲门HD小鼠中，表达短节段和全长突变体亨廷顿蛋白。我们将确定特定的雌激素受体调节剂（SERM）是否会增强线粒体PKA活性以及线粒体ER和CREB磷酸化以诱导影响神经元存活的线粒体基因转录。这些研究将提供预防线粒体转录功能障碍的新型机制，并有助于设计调节线粒体功能的适用化合物。