Xanthine Oxidase and Bioenergetic Function in Volume Overload

描述（由申请人提供）：心脏容量超负荷（VO）促进导致心力衰竭的生物能量、结构和功能变化。然而，心肌失代偿的机制和由此导致的进展失败，由于VO仍不清楚。它是建立，VO增加黄嘌呤氧化酶（XO）和活性氧和氮物种（ROS/RNS）。在这项提案中，我们将整合两个关键的基础研究结果，在心力衰竭的背景下，由于VO：1）XO作为一个来源的氧化损伤的心脏，由于VO和2）的核心作用线粒体功能障碍的病因VO介导的心力衰竭。这一概念将通过在靶向动物和人类研究中追求以下具体目标进行测试。目的1验证慢性VO时XO活性增高通过心肌线粒体功能障碍引起左室功能障碍的假说。目的2将使用基因治疗来敲低大鼠急性和慢性VO中的XDH，以验证心肌细胞源性XO活性负责心肌细胞MMP活化和线粒体功能障碍的假设。目的3将验证XO抑制剂在大鼠慢性ACF闭合后减轻心肌细胞氧化应激和线粒体功能障碍并改善LV功能的假设。这些实验将利用新的基因治疗技术在大鼠中证明XO在心肌细胞中的因果关系。心肌细胞线粒体功能的研究将使用Seahorse XF 24在动物细胞中进行。提出的动物和心肌细胞研究将确定增加XO是否是纯VO慢性拉伸中氧化应激和线粒体功能障碍的关键调节因子。这些研究，如果是积极的，可以提供科学的动力，XO抑制孤立VO患者的临床试验。

DESCRIPTION (provided by applicant): Volume overload (VO) in the heart promotes bioenergetic, structural, and functional changes that lead to heart failure. However, the mechanisms of myocardial decompensation and the resulting progression to failure due to VO remain unclear. It is established that VO increases xanthine oxidase (XO) and reactive oxygen and nitrogen species (ROS/RNS). In this proposal we will integrate two critical basic research findings in the context of cardiac failure due to VO: 1) XO as a source of oxidative damage in the heart due to VO and 2) the central role mitochondrial dysfunction in the etiology of VO-mediated heart failure. This concept will be tested through pursuit of the following specific aims in targeted animal and human studies. Aim 1 will test the hypothesis that increased XO activity in VO causes LV dysfunction through cardiomyocyte mitochondrial dysfunction in chronic VO in rat. Aim 2 will test the hypothesis that cardiomyocyte-derived XO activity is responsible for cardiomyocyte MMP activation and mitochondrial dysfunction using gene therapy to knockdown XDH in acute and chronic VO in rats. Aim 3 will test the hypothesis that XO inhibition reduces cardiomyocyte oxidative stress and mitochondrial dysfunction and improves LV function after closure of chronic ACF in rat. These experiments will utilize novel gene therapy techniques in rats to prove cause and effect of XO in cardiomyocytes. Studies of cardiomyocyte mitochondrial function will be performed using Seahorse XF24 in animal cells. The animal and cardiomyocyte studies proposed will determine whether increased XO is a key regulator of oxidative stress and mitochondrial dysfunction in the chronic stretch of a pure VO. These studies, if positive, could provide the scientific impetus for a clinical trial of XO inhibition in patients with isolated VO.