Systems Biology of Angiogenesis in Peripheral Arterial Disease

 描述（由申请人提供）：外周动脉疾病（PAD），由动脉粥样硬化引起，损害下肢血流，是一个主要的健康问题。目前还没有能够增加灌注和纠正受损血流的PAD药物治疗。迄今为止，涵盖数千名患者的数十项人体治疗性血管生成试验几乎全部失败。我们认为，PAD的人类血管生成治疗方案的部署没有充分认识到在分子、细胞、组织/器官和全身水平上调节众多竞争过程的复杂性，从而导致临床试验失败。为了从根本上理解这些现象并开发新的治疗方法，定量计算系统生物学方法与实验测量协同结合不仅是可取的，而且是绝对必要的。该项目的广泛目标是利用预测计算建模和体内实验的高度协同组合，对PAD中的血管生成进行定量了解;并进一步利用这些知识，设计改进的新型人类治疗方法。该项目提出了一种范式转变，从单纯通过给予促血管生成分子刺激血管生成到通过抑制内源性抗血管生成分子刺激血管生成。在具体目标1中，我们将扩展非缺血性和缺血性肌肉的系统表征，以了解血管内皮生长因子VEGFxxxb的先前未解释的内源性抗血管生成亚型的影响。我们将制定计算模型来预测健康非缺血小鼠肌肉和后肢缺血（HLI）后以及人类患者中VEGF受体-配体激活的动态，以探索PAD的新的潜在治疗靶点。在具体目标2中，我们将表征内源性抗血管生成蛋白血小板反应蛋白1（TSP 1）作为PAD的潜在治疗靶点。TSP 1是一种强抗血管生成剂，通过多种受体转导信号; TSP 1已被证明在PAD中升高。我们将重新开发通过TSP 1受体的信号转导的计算模型，同时考虑它们与VEGF途径的串扰。我们将在小鼠中进行体内实验，以定量TSP 1的作用，使用和不使用TSP 1及其受体的中和剂。该结果将为PAD的新治疗方法奠定基础。具体目标3致力于表征既存血管稀疏的影响。人PAD是一种慢性疾病，伴随多年的动脉粥样硬化累积，导致受影响的远端肌肉中的血管稀疏，而目前的PAD小鼠模型不具有这种预先存在的较低血管密度，从而人为地增加了治疗的感知有效性。我们将关注小鼠PAD模型的后期阶段，而不是更常见的急性阶段。该项目应带来重要的新知识和新的PAD治疗策略。

 DESCRIPTION (provided by applicant): Peripheral arterial disease (PAD), caused by atherosclerosis that impairs blood flow to the lower extremities, is a major health problem. Currently there are no pharmacological therapies for PAD that have the ability to increase perfusion and correct the impaired blood flow. To date, dozens of trials of therapeutic angiogenesis in humans covering thousands of patients have almost uniformly failed. We pose that human angiogenesis treatment regimens for PAD were deployed without an adequate appreciation of the complexities that regulate the numerous competing processes at the molecular, cellular, tissue/organ, and whole body levels; thus accounting for clinical trial failurs. To understand these phenomena at the fundamental level and to develop novel therapeutic approaches, quantitative computational systems biology approaches synergistically combined with experimental measurements are not only desirable but absolutely necessary. The broad goal of the project is to gain a quantitative understanding of angiogenesis in PAD, using a highly synergistic combination of predictive computational modeling and in vivo experiments; and further, using this knowledge, to design improved and novel human therapeutics. This project presents a paradigm shift from stimulating angiogenesis purely by administration of pro-angiogenic molecules to stimulating angiogenesis by inhibiting endogenous anti-angiogenic molecules. In Specific Aim 1 we will expand systems characterization of non-ischemic and ischemic muscle to understand the impact of previously unaccounted-for endogenous anti-angiogenic isoforms of vascular endothelial growth factor VEGFxxxb. We will formulate computational models to predict the dynamics of VEGF receptor-ligand activation in healthy non-ischemic mouse muscle and following hind-limb ischemia (HLI) and in human patients to explore novel potential therapeutic targets for PAD. In Specific Aim 2 we will characterize endogenous anti-angiogenic protein thrombospondin-1 (TSP1) as a potential therapeutic target for PAD. TSP1 is a strong anti-angiogenic agent transducing signals through multiple receptors; TSP1 has been shown to be elevated in PAD. We will develop, de novo, computational models of signal transduction through TSP1 receptors, also considering their crosstalks with the VEGF pathways. We will conduct in vivo experiments in mice to quantitate the role of TSP1, with and without administration of neutralizing agents for TSP1 and its receptors. The results will serve a basis for novel therapeutic approaches to PAD. Specific Aim 3 is devoted to characterization of the impact of pre- existing vascular rarefaction. Human PAD is a chronic disease that follows years of atherosclerotic buildup, resulting in vascular rarefaction in the affected distal muscle, whereas current mouse models of PAD do not have this pre-existing lower vascular density, thereby artificially increasing the perceived effectiveness of therapies. We will focus on later stages of the mouse PAD model, instead of the more common acute stage. The project should lead to important new knowledge and to novel therapeutic strategies in PAD.