Regulation of vascular remodeling & angiogenesis by Nogo

描述(申请人提供)：我们实验室发现RTN-4B(称为Nogo-B)是一种在血管内皮细胞(EC)和血管平滑肌(VSM)细胞中高度丰富的蛋白质，Nogo-B缺陷小鼠血管损伤后新生内膜加速，创面愈合缺陷，缺血后血流恢复受阻。在令人兴奋的初步数据中，我们发现内皮细胞中的Nogo-B在体外和体内调节急性炎症反应和中性粒细胞迁移。从机制上讲，Nogo的丢失抑制了ICAM-1介导的信号转导和EC中VE钙粘蛋白的磷酸化，这有助于减轻缺乏Nogo-B的小鼠的炎症。在另一系列检测NGBR细胞内功能的实验中，我们发现除了与Nogo-B结合外，NGBR还通过稳定Niemann Pick C2蛋白(NPC2)来调节细胞内的胆固醇代谢，这增加了Nogo-B/NGBR信号在胆固醇稳态的基本方面发挥基础作用的可能性。为了了解NGBR的整合作用，我们建立了条件基因敲除小鼠，并将检测其在Nogo-A/B KO小鼠中受损的几种实验性血管范例中的作用。因此，我们假设Nogo-B和NGBR是一种新的内源性调节系统，它协调对血管损伤或组织缺血的反应，并通过稳定NPC2来调节内质网(ER)功能，如胆固醇代谢。在这项提案中，我们将：1.确定Nogo-B如何调控白细胞跨内皮细胞迁移和血管炎症；2.检测Nogo-B对NGBR介导的NPC2稳定和细胞胆固醇代谢的调节；以及3.描述条件性NGBR基因敲除小鼠的特征。总体而言，这项建议的中心目标是广泛了解Nogo-B作为典型网状蛋白家族成员的功能，并研究其作为血管内稳态调节因子的功能。 公共卫生相关性：这项研究与公共健康相关，因为炎症是大多数心血管疾病的常见表现。我们的研究发现了动脉粥样硬化或高血压时血管功能和重塑的新调节剂。由这笔赠款支持的研究可能有助于确定减少心脏病和改善心血管疾病患者生活质量的新药。

DESCRIPTION (provided by applicant): Our lab discovered RTN-4B (called Nogo-B) as a protein highly abundant in endothelial cells (EC) and vascular smooth muscle (VSM) cells and mice deficient in Nogo-B have accelerated neointima after vascular injury, defective wound healing and impaired blood flow recovery post-ischemia. In exciting, preliminary data, we show that Nogo-B in the endothelium regulates the acute inflammatory response and neutrophil transmigration in vitro and in vivo. Mechanistically, the loss of Nogo suppresses ICAM-1 mediated signaling and the phosphorylation of VE cadherin in EC, which contributes to reduced inflammation in mice lacking Nogo-B. In a separate series of experiments examining the intracellular function of NgBR, we have discovered that in addition to binding Nogo-B, NgBR is critical for regulating intracellular cholesterol metabolism by stabilizing the Niemann Pick C2 protein (NPC2), raising the possibility that Nogo-B/NgBR signaling exerts a fundamental role in basic aspects of cholesterol homeostasis. In order to understand the integrated role of NgBR, we have generated conditional knockout mice and will examine its role in several experimental vascular paradigms that are impaired in Nogo-A/B KO mice. Thus, we hypothesize that Nogo-B and NgBR function as a novel endogenous regulatory system that coordinates the response to vascular injury or tissue ischemia and regulates endoplasmic reticulum (ER) functions such as cholesterol metabolism via stabilization of NPC2. In this proposal we will: 1. Define how Nogo-B regulates leukocyte transendothelial migration and vascular inflammation; 2. Examine Nogo-B regulation of NgBR mediated stabilization of NPC2 and cellular cholesterol metabolism; and 3. Characterize conditional NgBR knockout mice. Overall, the central goal of this proposal is to broadly understand the functions of Nogo-B as a prototypical reticulon family member and to examine its functions as a regulator of vascular homeostasis. PUBLIC HEALTH RELEVANCE: This research is relevant to public health since inflammation is a common manifestation of most cardiovascular diseases. Our research has discovered a new modulator of blood vessel function and remodeling during atherosclerosis or hypertension. Research supported by this grant may help identify new drugs that reduce heart disease and improve the quality of life of people suffering with cardiovascular disease.