Linking Spatial Variations in Shear Stress with Oxidation Stress

描述（由申请方提供）：流体剪切应力对血管内皮功能产生代谢和机械效应。剪切应力的空间（D/ x）和时间（D/ t）分量在很大程度上决定了血管氧化应激的局部性质，导致促炎状态。上一个资助期的重点是从静态模型（氧化生物学）到动态模型的研究（血管氧化应激），结合生物物理和生物化学方法的病理生理学意义的方法的范式转变。我们证明，D/ x和D/ t的变化差异调节O2的内皮生产。和NO，导致与动脉粥样硬化病变的起始相关的低密度脂蛋白（LDL）氧化修饰。我们开发了微机电系统（MEMS）传感器，以实时测量血管内的剪切应力在新西兰白色（NZW）兔的高胆固醇饮食，并应用我们的血管内的方法，猪模型。 我们对动脉粥样硬化保护性血流动力学增加线粒体膜电位（（m）伴随线粒体O2减少的机制有了新的认识。通过上调Mn-SOD活性而产生。相反，致动脉粥样硬化血流动力学和氧化LDL诱导线粒体O2。产生，通过c-Jun NH 2末端激酶（JNK）诱导的Mn-SOD泛素化和蛋白质降解导致细胞凋亡。我们的发现导致了一个新的观察，即血管壁中的活性脂质和巨噬细胞引起电化学修饰，可以通过电化学阻抗谱（EIS）测量。在这种情况下，我们假设，剪切应力调节线粒体氧化还原状态，调节血管氧化应激，引起明显的变化，电化学阻抗的非阻塞性，虽然炎症病变的地区。在新的目标1中，我们将提供一个EIS的离体模型;具体而言，同心双极微电极与人动脉和NZW兔动脉外植体的腔内表面之间的频率依赖性电和介电特性。在目标2中，我们将使用脂肪喂养的NZW兔建立EIS测量的体内模型;具体地，用于血管内EIS测量的电极的微制造和部署。在目标3中，我们将提供分子和遗传模型来证明氧化还原信号作为电化学修饰变化的潜在因素。下一个资助期的重点将整合电化学、氧化还原信号传导和遗传方法，以建立血管造影期间响应局部促炎状态而发生的特异性EIS，并有可能识别不稳定斑块。总之，我们实验室在上一个资助周期的出版记录（30位通讯作者）证明了我们在机械生物学和血管氧化应激研究方面的承诺和生产力。

DESCRIPTION (provided by applicant): Fluid shear stress imparts both metabolic and mechanical effects on vascular endothelial function. The spatial ( D/ x) and temporal ( D/ t) components of shear stress largely determine the focal nature of vascular oxidative stress, leading to pro-inflammatory states. The focus of the previous grant period was a paradigm shift in the approach from one of the static models (oxidative biology) to the dynamic models of investigation (vascular oxidative stress) that combined biophysical and biochemical approaches of pathophysiological significance. We demonstrated that variations in D/ x and D/ t differentially regulated the endothelial production of O2.- and .NO, leading to low density lipoprotein (LDL) oxidative modifications relevant for the initiation of atherosclerotic lesions. We developed microelectromechanical systems (MEMS) sensors to measure in real-time intravascular shear stress in the New Zealand White (NZW) rabbits on a hypercholesterolemic diet, and applied our intravascular methodology to the swine model. We gained new insights into the mechanisms whereby atheroprotective hemodynamics increased mitochondrial membrane potential ( (m) accompanied by a decrease in mitochondrial O2.- production via an up-regulation in Mn-SOD activities. In contrast, atherogenic hemodynamics and oxidized LDL induced mitochondrial O2.- production, leading to apoptosis via c-Jun NH2 terminal kinase (JNK)-induced Mn-SOD ubiquitination and protein degradation. Our finding led to a novel observation that active lipid and macrophages in the vessel wall cause electrochemical modifications that can be measured by electrochemical impedance spectroscopy (EIS). In this context, we hypothesize that shear stress regulates mitochondrial redox status, modulating vascular oxidative stress to cause distinct changes in electrochemical impedance in regions of non-obstructive, albeit inflammatory lesions. In the new Aim 1, we will provide an ex vivo model of EIS; specifically, the frequency-dependent electrical and dielectrical properties between concentric bipolar microelectrodes and endoluminal surface of explants of human arteries and NZW rabbit aortas. In Aim 2, we will establish an in vivo model of EIS measurements using fat-fed NZW rabbits; specifically, microfabrication and deployment of the electrodes for intravascular EIS measurements. In Aim 3, we will provide molecular and genetic models to demonstrate redox signaling as a requite factor underlying changes in electrochemical modifications. The focus in the next grant period will integrate electrochemical, redox signaling, and genetic approaches to establish specific EIS that occur in response to local pro- inflammatory states during angiograms with the possibility of identifying unstable plaque. In summary, the publication record (30 corresponding authors) of our laboratory in the previous funding cycle is a testimony of our commitment and productivity in mechanobiology and vascular oxidative stress research.