Multiscale, Transport-Dependent NO Signaling: Cells to Vascular Networks

描述(申请人提供)：拟议研究的目标是开发一个独特的多尺度数学模型，该模型将提供有关微循环中一氧化氮(NO)活动的机制的定量信息，并利用创新的实时实验来验证该模型。该模型将把细胞内NO的产生过程与细胞外、血管和组织的运输结合起来，包括正常条件下和高胆固醇血症下NO到O2的输送和代谢的耦合。该模型将有助于阐明NO的产生和运输机制，并对其血管扩张作用提供更深入的了解。虽然一氧化氮(NO)在调节血流和新陈代谢中的重要性已经得到了很好的证实，但许多NO的产生和运输机制尚未完全阐明。重要的是，可能影响NO生物利用度的各种现象和血管动力学在一系列时间和长度尺度上相互作用。为了理解系统的行为，需要一个跨越不同空间和时间尺度的数学模型，再加上体外和活体实验。数学建模：其开发理念是顺序地将较低尺度的模拟与较高尺度的模拟相结合：从细胞尺度到血管尺度，再到血管网络。模拟的预测将使用我们的实验和文献中报告的结果进行验证。在VITR：以前设计和建造的平行板层流流室，这是我们团队第一次也是唯一一次能够在广泛的条件下直接、实时地测量NO释放的动力学，将用于细胞培养研究。我们将研究剪切力和信号分子质量传输变化对流动诱导的NO产生的耦合作用，以分离它们是如何影响NO的产生和传输的。结果将与模拟结果进行比较。体内：将使用大鼠肠系膜和载脂蛋白E缺陷小鼠进行实验。在正常和异常生理条件下，测量单个小动脉、小动脉、小静脉和小静脉的局部血流量、PO2和NO，并结合血管内径测量，以表征血管内径、NO、血流量和O2输送之间的关系。还将评估在低氧条件下，亚硝酸盐作为NO来源对血液和组织中依赖O2的亚硝酸还原酶活性的影响。建议的模型将导致对整个系统的更好的理解，并为未来的研究奠定基础，从而揭示与NO相关的病理学。

DESCRIPTION (provided by applicant): The goal of the proposed research is to develop a unique multi-scale mathematical model that will provide quantitative information regarding mechanisms governing nitric oxide (NO) activity in the microcirculation and to utilize innovative, real-time experiments to validate the model. The model will integrate intracellular NO production processes with extracellular, vascular and tissue transport, including the coupling of NO to O2 delivery and metabolism under normal conditions and in hypercholesterolemia. The model will help to elucidate mechanisms by which NO is produced and transported and provide greater insight into its vasodilatory role. While the importance of nitric oxide (NO) in regulating blood flow and metabolism is well established, many of the mechanisms by which NO is produced and transported have not been fully elucidated. Importantly, the various phenomena that can potentially affect the bioavailability of NO and vascular dynamics interact over a range of time and length scales. A mathematical model that transcends different spatial and time scales, coupled with in vitro and in vivo experiments, is required for understanding of system behavior. Mathematical Modeling: The development philosophy is to sequentially couple lower scale with higher scale simulation: cell-scale to vessel-scale, to vascular networks. Predictions of the simulation will be validated using our experiments and results reported in the literature. In vitr: A parallel plate laminar flow chamber, designed and constructed previously, which -- for the first time and only by our group -- enables direct, real time measurements of the kinetics of NO release under a wide range of conditions will be used for cell culture studies. The coupled effects of shear stress and altered mass transport of signaling molecules on flow- induced NO production will be investigated to isolate how they influence NO production and transport. Results will be compared with the simulations. In vivo: Experiments will be performed using the rat mesentery and apolipoprotein-E deficient mice. Local blood flow, PO2 and NO, combined with vessel diameter measurements, will be obtained from individual small arteries, arterioles, venules, and small veins under normal and abnormal physiological conditions to characterize relationships among vascular diameter, NO, blood flow, and O2 delivery. The effect of nitrite as an NO source from O2-dependent nitrite reductase activity in blood and tissue under hypoxic conditions will also be evaluated. The proposed model will lead to an improved understanding of the complete system, and set the groundwork for future research that can shed light on NO-related pathologies.