Redox Mechanisms of Respiratory Muscle Stress Adaptation

骨骼肌产生活性氧（ROS）以响应各种应激刺激，包括 热应激、渗透应激、强刺激和缺氧。这些信号似乎在功能上 但在大多数正常生理条件下不会造成损伤或损害。我们假设 在这种情况下，ROS在信号网络中起着重要作用， 应力当前提案的重点将放在从高O2到低O2转变过程中产生的ROS上 在骨骼肌中。这一现象与缺氧诱导的氧化还原态的转变是一致的。 细胞（NADH/NAD+），但我们不知道信号是否来自氧化还原或其他缺氧的变化- 诱导细胞反应。我们也不知道这种信号的亚细胞起源或什么表型 该提案的AIM 1将确定ROS形成的主要细胞和亚细胞来源 它将决定ROS生成系统对代谢应激的敏感性， PO 2的变化与NADH/NAD+的变化。为了实现这一目标，我们设计了新的成像方法， 包括多光子寿命和荧光寿命，以及一种新的超氧阴离子荧光定位探针 靠近膜。我们还将通过测量来确定关键刺激方式和强度， 独立地操纵PO 2和电池氧化还原状态。在AIM 2中，我们将研究 低氧诱导的ROS。我们假设应激诱导的活性氧促进能量动员， 能量消耗首先，我们将评估AMP依赖性蛋白激酶和糖酵解的潜在作用， 通量作为应激诱导的ROS的可能靶点。其次，我们将确定ROS如何影响 Ca+2释放和力之间的关系以及ROS和细胞氧化还原状态在细胞内的潜在作用。 改变Ca+2诱导的力。这项基础科学研究将为基本的骨骼 肌肉生物学将应用于与O2运输限制相关的各种肌肉疾病。

Skeletal muscles produce reactive oxygen species (ROS) in response to a variety of stress stimuli, including thermal stress, osmotic stress, intense stimulation and hypoxia. These signals appear to be functionally significant but do not cause injury or damage under most normal physiologic conditions. We hypothesize that ROS, in this setting, play important roles in signaling networks designed to assist cells to withstand stress. The focus of the current proposal will be on the ROS produced in the transition from high to low O2 in skeletal muscle. This phenomenon is coincident with the hypoxia-induced shift in the redox state of the cell (NADH/NAD+), but we do not know if the signal arises from changes in redox or some other hypoxia- induced cellular response. We also do not know the sub-cellular origins of this signal or what phenotype produces it. AIM 1 of the proposal will identify the primary cellular and subcellular origins of ROS formation produced during metabolic stress and it will determine the sensitivity of the ROS-generating system to changes in PO2 vs. shifts in NADH/NAD+. To address this aim we have designed new imaging methods, including multiphoton and fluorescence lifetime, and a new fluorescent probe for localization of superoxide close to membranes. We will also determine the critical stimulus modality and intensity by measuring, and independently manipulating PO2 and cell redox state. In AIM 2, we will study the functional significance of hypoxia-induced ROS. We hypothesize that stress-induced ROS promotes energy mobilization and inhibits energy expenditure. First, we will evaluate the potential role of AMP-dependent protein kinase and glycolytic flux as a possible target for stress-induced ROS. Second, we will determine how ROS influences the relationships between Ca+2 release and force and the potential roles ROS and cell redox state have in altering Ca+2-induced force. This basic science investigation will give new insights into fundamental skeletal muscle biology that will have applications to a variety of muscle disorders related to O2 transport limitation.