Neuropeptide Y in Revascularizing Ischemic Tissues

描述(来自应用程序的逐字记录)：心脏和外围设备 血管疾病时，血管新生可改善血液流动，利于长期 缺血组织的存活率。这一复杂的过程涉及内皮细胞 (ECS)与血管平滑肌细胞(VSMC)的黏附、迁移、增殖 和差异化。碱性成纤维细胞生长因子等体液因子 (碱性成纤维细胞生长因子)和血管内皮生长因子(VEGF)被认为是 这一进程的调解人。然而，船只也被丰富的 交感神经，已知含有营养因子。最近，我们 发现神经肽Y(NPY)，一种交感神经递质刺激 体外和体内血管生成，其效力和疗效可与 碱性成纤维细胞生长因子和血管内皮细胞生长因子的表达。此外，人内皮细胞具有完整的神经肽Y自分泌 系统，它合成NPY及其受体(Rs；Y1-Y5)以及 转换酶，二肽基肽酶IV(DPPIV)。在过去的两年里我们 一项重大发现，在体内大鼠血管新生模型中，股动脉 闭塞，从而导致肢体缺血导致大量NPY从 缺血小腿但未检测到NPY受体，从而阻止NPY发挥其作用 血管生成活性。在后续研究中，我们证明了局部NPY 给药后，神经肽Y受体上调，毛细血管密度恢复 骨骼肌达到非缺血腿部观察到的水平。基于这些 令人兴奋的发现，我们现在建议确定NPY是否构成了一个新的 缺血刺激的内源性血管生成系统，并测定 血管生成受体的亚型和NPY的作用机制。为此，有两个 建立缺血模型：后肢(大鼠和小鼠)和心脏(大鼠)。 具体目的是确定：1)缺血/缺氧是否上调NPY的释放 及其受体在血管生成时空关系中的表达 缺血组织和体外内皮细胞；2)神经肽Y的作用机制 血管生成效应及其对DPPIV的依赖以及与其他药物的相互作用 生长因子：(碱性成纤维细胞生长因子、血管内皮生长因子、一氧化氮)；3)五种NPY受体中的哪一种 血管生成；以及4)如果特定的NPY受体激动剂使缺血的血管重新血运 心脏和后肢。我们将重点介绍Y2和Y5亚型，它们是 我们最近的发现表明，但主要的血管NPY的作用 R，即Yl，也将接受调查。这些研究将在大鼠身上进行 用NPY(或其他因素)处理缓释微丸或过度表达 NPY基因，以及在NPY、Y1、Y2和Y5基因敲除(KO)小鼠中。血管生成 A(S)将通过KO研究其基因和蛋白的表达来确定 小鼠和/或特异性NPY受体激动剂或拮抗剂 模型，以及体外血管生成试验。NPY的血管生成活性将 在结构上进行评估(例如，通过血管造影术、组织病理学、毛细血管/纤维 比率和有丝分裂指数)和功能(通过局部血流量、心脏 产量和运动评分表)。这项研究将是第一个建立 神经肽Y在缺血诱导的血管生成中的作用 NPY是调解这一行动的机构。除了提供对 NPY作为神经源性血管生成的中介的作用，这些发现将打开 治疗缺血性疾病的新途径。

DESCRIPTION (Verbatim from the application): In the heart and peripheral vascular diseases, angiogenesis can improve blood flow and facilitate long-term survival of ischemic tissues. This complex process involves endothelial cell (ECs) and vascular smooth muscle cell (VSMC) adhesion, migration, proliferation and differentiation. Humoral agents such as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have been suggested as mediators of this process. However, vessels are also richly innervated with sympathetic nerves, which are known to contain trophic factors. Recently, we discovered that neuropeptide Y (NPY), a sympathetic transmitter stimulates angiogenesis in vitro and in vivo, with potency and efficacy comparable to those of bFGF or VEGF. In addition, human ECs possess a complete NPY autocrine system, which synthesizes NPY and its receptors (Rs; Y1-Y5)as well as the "converting enzyme," dipeptidyl peptidase IV (DPPIV). In the last two years we made a major discovery that in the in vivo rat angiogenic model, femoral artery occlusion and hence limb ischemia results in substantial NPY release from the ischemic leg yet no NPY Rs are detected, thus preventing NPY from exerting its angiogenic activity. In a follow up study, we demonstrated that local NPY administration, both up-regulates NPY Rs and restores capillary density in the skeletal muscles to the level observed in the non-ischemic leg. Based on these exciting discoveries, we now propose to establish if NPY constitutes a new endogenous angiogenic system stimulated by ischemia, and to determine the subtypes of angiogenic Rs and mechanisms of NPY action. To this end, two ischemic models are proposed: the hindlimb (rat and mouse) and the heart (rat). Specific aims are to determine: 1) if ischemia/hypoxia up-regulates NPY release and the expression of its Rs in spatial and temporal relation to angiogenesis in the ischemic tissues, and in vitro in ECs; 2) the mechanisms of NPY's angiogenic effects and its dependence on DPPIV, and interactions with other growth factors: (bFGF, VEGF, nitric oxide); 3) which of the five NPY Rs are angiogenic; and 4) if the specific NPY R agonist revascularizes the ischemic heart and hindlimb. We will focus on the Y2 and Y5 subtypes, which are suggested by our recent findings, but the role of the predominant vascular NPY R, the Yl, will also be investigated. These studies will be performed in rats treated with NPY (or other factors) in slow release pellets or over-expressing the NPY gene, and in NPY, Yl, Y2, and Y5 knockout (KO) mice. The angiogenic A(s) will be determined by studying their mRNA and protein expression using KO mice and/or specific NPY R agonists or antagonists in the above ischemic models, and in the in vitro angiogenic assays. NPY's angiogenic activity will be assessed structurally (e.g. by angiograms, tissue pathology, capillary/fiber ratio, and mitotic index) and functionally (by regional blood flow, cardiac output and motor scoring scale). This research will be the first to establish the role of NPY in ischemia-driven angiogenesis, and to determine the specific NPY Rs mediating this action. In addition to providing an understanding of the NPY's role as a mediator of neurogenic angiogenesis, these findings will open new avenues for treatment of ischemic diseases.