Mechanisms of ROS Balance and Cardiac Energy Metabolism in Diabetes Mellitus

项目摘要 在这项建议中，我们旨在研究活性氧物种(ROS)的综合代谢和 能量学，通过实验和计算建模，应用了最近引入的两个概念：“氧化还原- 优化的ROS平衡“(R-OR Balance)，以及”弥散循环控制“。为了综合分析 一种重要疾病能量和ROS平衡的控制和调节机制 公共卫生，我们将研究2型糖尿病(T2 DM)大鼠模型的工作心肌， 重点关注胰岛素和二甲双胍对能量和ROS通路的影响。 在糖尿病心肌中，我们试图了解能量和ROS通量以及 它们与氧化还原环境的关系，我们将重点讨论胰岛素和二甲双胍(一种广泛使用的药物)的作用 降血糖药物)对代谢控制的影响。这些研究将使用最先进的量化工具 基于抑制剂滴定方法的代谢控制分析，以及基于之后的瞬变分析 稳态区的摄动。我们计划监测大鼠心脏的代谢变量和ROS 在力传感器装置的工作条件下，装载有荧光指示器的小梁。这个 实验结果将被用来约束和微调心肌细胞的计算模型 整合机械、电生理和代谢活动(ECME模型)。到目前为止，ECME模式 已经能够成功地模拟i)线粒体膜电位振荡的行为， NADH、谷胱甘肽和ROS，II)线粒体NADH、钙和ADP的动态变化 心脏的供需，以及iii)心肌细胞膜电位的动态变化。 在经历心律失常的整个心脏中的线粒体振荡。 该模型将扩展到包括乙酰辅酶A上游的途径，即糖酵解、戊糖 磷酸盐途径和β-氧化。电子输运的更详细的数学描述 呼吸链和ROS清除途径的复合体将能够解释 ROS平衡的机制。计算模型将受到新陈代谢控制，以努力 确定参与控制和调节能源和ROS路径网络的步骤。 我们相信，为了合理地干预治疗和预防 关于心血管系统的疾病，对代谢的综合行为有更深入的了解 网络是必需的。这证明了我们试图建立一个计算模型的合理性，该模型将导致 了解心脏生理学的失调方面，并指出可能的潜在靶点 用于药理学、营养学或基因疗法的治疗干预。

Project Summary In this proposal we aim to study the integrated metabolism of reactive oxygen species (ROS) and energetics, experimentally and by computational modeling, applying two recently introduced concepts: "Redox- optimized ROS balance" (R-OR balance), and "control by diffuse loops". In order to analyze in an integrated manner the mechanisms of control and regulation of energy and ROS balance in an important disease for public health, we will investigate working cardiac muscle in a type 2 diabetes mellitus (T2DM) rat model, focusing on the effects of insulin and metformin upon energy and ROS pathways. In the diabetic cardiac muscle, we seek to understand the interdependence of energy and ROS fluxes and their relation to the redox environment, We will focus on the effects of insulin and metformin (a widely-used anti-hyperglycemic drug) on metabolic control. These studies will apply state of the art quantitative tools of metabolic control analysis based on the inhibitor titration method, and on the analysis of transients after perturbation of the steady state regime. We plan to monitor metabolic variables and ROS in rat cardiac trabeculae loaded with fluorescent indicators, under working conditions in a force transducer device. The experimental results will be used to constrain and fine-tune a computational model of the cardiac myocyte that integrates mechanical, electrophysiological and metabolic activities (ECME model). So far, the ECME model has been able to successfully simulate the behavior of i) oscillations in mitochondrial membrane potential, NADH, glutathione, and ROS, ii) the dynamics of mitochondrial NADH, calcium, and ADP during changes in supply and demand in the heart, and iii) the dynamics of the sarcolemmal membrane potential during mitochondrial oscillations in whole hearts undergoing arrhythmias. The model will be extended to incorporate pathways upstream Acetyl CoA, namely glycolysis, pentose phosphate pathways and beta-oxidation. A more detailed mathematical description of the electron-transport complexes of the respiratory chain, and of the ROS scavenging pathways, will enable accounting for the mechanisms of ROS balance. The computational model will be subjected to metabolic control in an effort to identify the steps that participate in the control and regulation of the network of energy and ROS pathways. We are convinced that in order to perform a rational intervention in the treatment and prevention of a disease regarding the cardiovascular system, a deeper understanding of the integrated behavior of metabolic networks is needed. This justifies our attempt to build a computational model that will lead to a quantitative understanding of the dysfunctional aspects of heart physiology, and point out potential targets that could be used for therapeutic interventions, either pharmacological, nutritional or by gene therapy.