Reactive Oxygen Species and Respiratory Muscle Dysfunction in Heart Failure

摘要 膈肌无力是慢性心力衰竭患者的一个重要健康问题， 射血分数（CHF），因为它会损害通气和气道清除率并导致心脏病 心律失常、外周血管收缩和肢体肌肉疲劳。生产和清除的不匹配 活性氧（ROS），伴随着肌原纤维蛋白的氧化修饰，是一个关键的 比力损失的决定因素（即，收缩功能障碍）。在本提案中，我们的目标是确定 引起膈肌氧化还原失衡和ROS介导的收缩功能障碍的机制 单位：瑞士法郎。根据我们在上一个资助周期收集的数据和初步研究， 知识从现有的文献中，我们提出了三个具体的目标来实现我们的目标。在目标1中，我们 确定是否下调转录因子，这是已知的调节几个氧化还原基因， 隔膜对于过量的ROS和CHF中的虚弱是足够的和必需的。在目标2中，我们将定义 蛋白质氧化在心力衰竭膈肌无力中的作用和机制。我们的初步数据显示， 逆转特定巯基氧化的酶的过表达阻止CHF诱导的收缩性心肌炎。 功能障碍我们将扩大这些研究，以确定这些酶在CHF诱导的保护作用。 横膈膜无力以及参与这一过程的细胞和分子机制。目标3将测试 膈肌α-肌动蛋白（骨骼肌）氧化作为CHF诱导收缩的重要分子事件 功能障碍肌动蛋白是特别相关的，因为它含有对蛋白质高度敏感的氨基酸残基。 蛋白质结构和功能关键区域的氧化。我们将使用病毒介导的质粒转导 以引发相关基因的过度表达和敲低。一般的主要因变量是 完整束和透化单纤维的隔膜收缩特性，肌肉超微结构，RNA- 测序，活性氧排放和氧化还原平衡的标志物，蛋氨酸氧化还原蛋白质组学。的目标和 在我们的建议实验将建立呼吸肌生物学，氧化还原介导的深入了解 收缩功能障碍，并确定新的机制和目标，以治疗膈肌无力的CHF。

Abstract Diaphragm weakness is a significant health problem in patients with chronic heart failure and reduced ejection fraction (CHF) because it compromises ventilation and airway clearance and contributes to cardiac arrhythmias, peripheral vasoconstriction, and limb muscle fatigue. A mismatch in production and scavenging of reactive oxygen species (ROS), accompanied by oxidative modifications of myofibrillar proteins, is a critical determinant of loss of specific force (i.e., contractile dysfunction) in CHF. In this proposal, our goal is to identify the mechanisms which are causative in diaphragm redox imbalance and ROS-mediated contractile dysfunction in CHF. Based on our data collected during the previous funding cycle and preliminary studies, coupled with knowledge from the existing literature, we propose three specific aims to achievel our goal. In Aim 1, we will determine whether downregulation of a transcription factor, which is known to regulate several redox genes, in the diaphragm is sufficient and required for excess ROS and weakness in CHF. In Aim 2, we will define the role and mechanisms of protein oxidation on diaphragm weakness in CHF. Our preliminary data suggests that overexpression of enzymes that reverse oxidation of specific thiol groups prevents CHF-induced contractile dysfunction. We will expand on these studies to define the protective effects of these enzymes in CHF-induced diaphragm weakness and the cellular and molecular mechanisms involved in this process. Aim 3 will test oxidation of diaphragm α-actin (skeletal) as an essential molecular event in CHF-induced contractile dysfunction. Actin is particularly relevant because it contains amino acid residues that are highly sensitive to oxidation in regions critical for protein structure and function. We will use viral-mediated plasmid transduction to elicit overexpression and knockdown of the relevant genes. The general main dependent variables are diaphragm contractile properties in intact bundles and permeabilized single fibers, muscle ultrastructre, RNA- Sequencing, ROS emission and markers of redox balance, and methionine redox proteomics. The aims and experiments in our proposal will build an in-depth understanding of respiratory muscle biology, redox-mediated contractile dysfunction, and identify novel mechanisms and targets to treat diaphragm weakness in CHF.