Transcriptional and physiological analysis of cardiac HIF1

描述(申请人提供)：低氧诱导因子-1是所有脊椎动物的主要氧气感应分子。它是一种转录因子，受环境氧浓度对其稳定性的影响而调节。HIF1调节与低氧反应有关的一系列基因，包括促进血管生成和有利于糖酵解代谢的因子。这些反应在任何地方都比心脏更令人关注，在发达国家，冠状动脉疾病引起的缺氧是发病率和死亡率的主要原因。因此，我们试图确定HIF1在心脏中的作用，以更好地了解缺氧的内源性生理反应。我们已经创建了一种转基因模型，在该模型中，HIF可以以一种受调控的、心脏特异的方式表达。我们已经用一种不受氧气浓度影响的抗降解HIF1产生了我们的转基因动物。我们的基本假设是，心脏特异性HIF1活性的升高将引导心脏概括缺氧反应。我们的具体目标是使用分子、代谢和生理技术的组合来检验这一假说。具体目标1：确定体内HIF1转录激活的直接下游靶点。随着HIF1活性的增加，我们将对我们的模型进行全面的转录分析，以捕捉第一反应并识别受HIF1调控的新基因。具体目标2：测量特定的生化途径在HIF1介导的心脏从氧化代谢到糖酵解代谢的转换中的作用。这将通过自旋标记底物的磁共振光谱来实现。具体目的3：明确HIF1在心脏中的过度表达对血管生成的影响。这将需要组织学和生理学分析，并将在缺氧和脑梗塞模型中进行探索。

DESCRIPTION (provided by applicant): Hypoxia inducible factor-1 is a principal oxygen sensing molecule in all vertebrates. It is a transcription factor that is regulated by the effect of ambient oxygen concentration on its stability. HIF1 regulates a panoply of genes involved in response to hypoxia, including factors that augment angiogenesis and favor glycolytic metabolism. Nowhere are these responses of greater interest than in the heart, where hypoxia due to coronary artery disease is a major cause of morbidity and mortality in the developed world. We thus seek to determine the effects of HIF1 in the heart, to better understand the endogenous physiological response to hypoxia. We have created a transgenic model where HIF can be expressed in a regulated, cardiac-specific manner. We have generated our transgenic animal with a degradation-resistant HIF1 that is not affected by oxygen concentration. Our underlying hypothesis is that cardiac-specific elevation of HIF1 activity will direct the heart to recapitulate hypoxic responses. Our specific aims test this hypothesis using a combination of molecular, metabolic and physiological techniques. Specific Aim 1: To identify the immediate down-stream targets of HIF1 transcriptional activation in vivo. We will apply comprehensive transcriptional analysis to our model as HIF1 activity increases to catch the first response and identify novel genes that are regulated by HIF1. Specific Aim 2: To measure the contribution of specific biochemical pathways to the HIF1-mediated switch from oxidative to glycolytic metabolism in the heart. This will be accomplished with the magnetic resonance spectroscopy of spin-labeled substrates. Specific Aim 3: To define the angiogenic effects of HIF1 overexpression in the heart. This will require histological and physiological analysis and will be explored in models of hypoxia and infarction.