NPY and Angiogenesis in Adipose Tissue

描述（申请人提供）：白色脂肪组织（WAT）是高度血管化的，其生长可以被抗血管生成药物抑制，是治疗肥胖的新方法。在之前的资助期内，我们发现神经肽Y (NPY)，一种交感递质，通过其gi偶联的Y2受体，二肽基肽酶IV （DPPIV，一种形成Y2激动剂的酶）和内皮型一氧化氮合酶（eNOS）有效地血管生成，并刺激缺血，动脉粥样硬化，肿瘤和视网膜病变的血管生成。由于WAT有交感神经，应激可激活它们，我们假设NPY是WAT血管生成和脂肪生成的神经源性介质。在初步研究中，当局部应用于ob/ob小鼠腹部WAT时，NPY增加，而Y2拮抗剂减少脂肪沉积（MRI）和血管密度；同样，Y2-/-小鼠的冷应激和高脂肪饮食引起的腹部肥胖也减少了。为了确定NPY是否激活血管生成脂肪的营养循环，以及通过何种机制，将在人类WAT和小鼠中研究血管生成和脂肪生成，野生型和Y2， DPPIV, eNOS （NPY的血管生成信号）及其衍生细胞的缺失。为了模拟WAT中神经血管-脂肪细胞的交叉对话，我们将使用已建立的NPYergic交感神经母细胞瘤或大鼠颈上神经节与来自人和鼠WAT的内皮细胞或前脂肪细胞共培养。NPY神经元表达的上游调节剂及其血管生成和脂肪生成/抗脂肪分解的下游调节剂将在Aims 1-2中确定。目的3将测试异种移植裸鼠模型中人类或小鼠脂肪垫的生长是否受到NPY或宿主交感神经支配（交感神经切除术）的刺激，并依赖于血管生成（MRI、超声、组织学）。在Aim 4中，NPY和Y2Rs的作用将在遗传或应激+高脂肪饮食诱导的肥胖中得到证实，使用Y2拮抗剂局部治疗并产生内皮细胞和脂肪细胞特异性的条件Y2敲除。如果得到证实，NPY及其Y2Rs可能因其血管生成活性而成为应激依赖性肥胖的新危险因素。

DESCRIPTION (provided by applicant): White adipose tissue (WAT) is highly vascularized and its growth can be inhibited by anti-angiogenic drugs, promising new treatment for obesity. In the previous grant period, we discovered that neuropeptide Y (NPY), a sympathetic transmitter, is potently angiogenic via its Gi-coupled Y2 receptors, dipeptidyl peptidase IV (DPPIV, an enzyme forming Y2 agonist) and an endothelial nitric oxide synthase (eNOS) - and stimulates angiogenesis in ischemia, atherosclerosis, tumors and retinopathy. Since WAT has sympathetic nerves and stress activates them - we hypothesized that NPY is a neurogenic mediator of WAT angiogenesis and adipogenesis. In pilot studies, NPY increased, while Y2 antagonist decreased fat deposits (MRI) and vascular density when applied locally into abdominal WAT of ob/ob mice; similarly, cold stress- and high fat diet-induced abdominal obesity was reduced in Y2-/- mice. To determine if NPY activates angiogenic adipogenic trophic cycle, and by which mechanisms, angiogenesis and adipogenesis will be studied in human WAT and mice, wild type and null for Y2, DPPIV, eNOS (NPY's angiogenic signals), and cells derived from them. To mimic nerve-vessel-adipocyte cross-talk in WAT, we will use established co-culture of NPYergic sympathetic neuroblastoma or rat superior cervical ganglia with endothelial cells or preadipocytes from human and murine WAT. Upstream modulators of NPY neuronal expression and its downstream modulators of angiogenesis and adipogenesis/anti-lipolysis will be determined in Aims 1-2. Aim 3 will test if growth of human or murine fat pad in a xenograft nude mouse model is stimulated by NPY or host sympathetic innervation (sympathectomy) and dependent on angiogenesis (MRI, ultrasound, histology). In Aim 4, the role of NPY and Y2Rs will be confirmed in genetic or stress+high fat diet-induced obesity, using local treatment with Y2 antagonist and generating endothelial and adipocyte-specific conditional Y2 knockouts. If proven, NPY and its Y2Rs may become a new risk factor for stress-dependent obesity, due to its angiogenic activity.