Neuropeptide Y in Revascularizing Ischemic Tissues

神经肽 Y 在缺血组织血运重建中的作用

• 批准号: 6538002
• 负责人: ZOFIA ZUKOWSKA
• 金额: $ 38.89万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6538002
• 关键词: angiogenesis; blood flow measurement; fibroblast growth factor; histology; ischemia; laboratory mouse; laboratory rat; myocardial ischemia /hypoxia; neuropeptide Y; neuropeptide receptor; nitric oxide; protein isoforms; vascular endothelial growth factors

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.

描述（逐字化的应用程序）：心脏和周围 血管疾病，血管生成可以改善血流并促进长期 缺血组织的存活。这个复杂的过程涉及内皮细胞 （ECS）和血管平滑肌细胞（VSMC）粘附，迁移，增殖 和分化。诸如基本成纤维细胞生长因子等体液剂 （BFGF）和血管内皮生长因子（VEGF）已被认为为 这个过程的调解人。但是，血管也有丰富的支配 交感神经，已知包含营养因素。最近，我们 发现神经肽Y（NPY），一种交感性发射器刺激 体外和体内血管生成，效力和功效可与 BFGF或VEGF的那些。此外，人类EC拥有完整的NPY自分泌 系统，合成NPY及其受体（Rs; Y1-Y5）以及 “转化酶”，二肽基肽酶IV（DPPIV）。在过去的两年中 提出了一个重大发现，即在体内大鼠血管生成模型中股动脉 闭塞和肢体缺血导致大量的NPY释放 缺血性腿但未检测到NPY RS，从而阻止了NPY施加 血管生成活性。在后续研究中，我们证明了当地的NPY 给药，既可以上调NPY RS并恢复毛细血管密度 骨骼肌达到非缺血性腿中观察到的水平。基于这些 令人兴奋的发现，我们现在建议确定NPY是否构成新的 缺血刺激的内源性血管生成系统，并确定 NPY作用的血管生成RS和机制的亚型。为此，两个 提出了缺血模型：后肢（大鼠和小鼠）和心脏（大鼠）。 具体目的是确定：1​​）如果缺血/缺氧会上调NPY释放 以及其RS在与血管生成的空间和时间关系中的表达 在缺血组织中，在EC中体外； 2）NPY的机制 血管生成效应及其对DPPIV的依赖，以及与其他的相互作用 生长因子：（ BFGF，VEGF，一氧化氮）； 3）五个NPY RS中的哪个是 血管生成； 4）如果特定的npy r激动剂血运重建 心脏和后肢。我们将专注于Y2和Y5子类型 我们最近的发现建议，但主要的血管NPY的作用 R，YL也将进行调查。这些研究将在大鼠中进行 用NPY（或其他因素）在缓慢释放的颗粒或过表达中处理 NPY基因以及NPY，YL，Y2和Y5敲除（KO）小鼠。血管生成 A将通过使用KO研究其mRNA和蛋白质表达来确定A 上述缺血中的小鼠和/或特定的npy r激动剂或拮抗剂 模型，以及在体外血管生成测定中。 NPY的血管生成活动将 在结构上进行评估（例如，通过血管造影，组织病理学，毛细血管/纤维 比率和有丝分裂指数）和功能（通过区域血流，心脏 输出和电动机评分量表）。这项研究将是第一个建立 NPY在缺血驱动的血管生成中的作用，并确定特异性 NPY RS调解此动作。除了提供对 NPY作为神经源性血管生成的介体的作用，这些发现将打开 治疗缺血性疾病的新途径。