Macrophage and Vascular Smooth Muscle Cell dialogue: role in aortic aneurysm

项目摘要 腹主动脉瘤(Aaa)是一种常见的血管疾病，与炎症和血管表达上调有关。 导致细胞外基质(ECM)局部降解的基质金属蛋白酶(MMPs) 最终导致严重受损的主动脉壁破裂，危及生命。AAA的发病率为 高得令人无法接受。尽管在初级预防措施方面取得了进展，但美国儿科协会仍导致13000人死亡 每年由于美国的AAA破裂。因为这些机制中的主要知识空白 有助于持续的细胞外基质降解，目前还没有基于药物的疗法来规避AAA， 手术是克服或推迟患者负担的唯一选择。我们小组之前的工作已经完成 确定了神经元引导信号netrin-1在促进血管炎症方面的工具作用。 巨噬细胞在受损血管壁上的穿透是AAA的一个重要标志。他们在其中扮演的角色 在AAA中持续的ECM降解仍然知之甚少。这项提案的目标是将 Netrin-1在AAA中维持ECM破坏中的作用。中心假说是巨噬细胞衍生的 Netrin-1是一种病理信号，能够刺激血管平滑肌细胞(VSMC)中基质金属蛋白酶的激活，并 这种串扰机制的破坏对AAA的病理性血管重构具有保护作用。我们的 基本原理是基于在K99/R00颁奖期间所做的重要观察，即在 造血细胞(Ntn1-/-)可防止AAA的发展和弹性蛋白的断裂。单细胞RNA 测序结果表明，netrin-1存在于跨壁巨噬细胞中。重要的是，RNA测序 WT和Ntn1-/-主动脉证实，在Netrin-1缺陷小鼠的VSMC中，MMP3的表达下调。在我们的 将使用新的小鼠模型组织特异性或有条件地删除巨噬细胞中的netrin-1， VSMC中MMP3和新生素(netrin-1的受体)的缺失以确定这一指导信号是如何发出的 策划了一系列事件，通过增加催化酶的供应来导致ECM的持续降解 到腹部组织。这项拟议的研究具有创新性，因为我们调查了Netrin-1在 介导串扰启动和有害的血管重塑，这是迄今为止未被研究的机制 AAA。最后，我们将了解netrin-1在通过复合体同步ECM损伤中的作用 AAA的作用机制。这一贡献意义重大，因为我们将测试在AAA之后是否靶向Netrin-1 已建立的(可诱导缺失的小鼠模型)可以逆转ECM的降解，防止破裂。在……里面 这种翻译方法，我们的数据将为开发有前景的预防性治疗铺平道路 旨在靶向netrin-1或拮抗其信号事件以防止AAA的策略。

Project Summary Abdominal aortic aneurysm (AAA) is a common vascular disorder associated with inflammation and upregulation of matrix-metalloproteinases (MMP), which cause the local degradation of the extracellular matrix (ECM) culminating in life-threatening rupture of the excessively damaged aortic wall. The incidence of AAA is unacceptably high. Despite progress in primary preventive measures, AAA still accounts for > 13000 deaths annually due to ruptured AAA in the United States. Because major knowledge gaps in the mechanisms that contribute to sustained ECM degradation persist, there is currently no drug-based therapy to circumvent AAA, surgery is the only alternative to overcome or delay the burden of patients. Previous work from our group has identified an instrumental role for the neuronal guidance cue, netrin-1 in fostering vascular inflammation. Transmural macrophage infiltration in the damaged vascular wall is a key hallmark of AAA. Their role in sustaining ECM degradation in AAA remains poorly understood. The objective of this proposal is to characterize the role of netrin-1 in sustaining ECM destruction in AAA. The central hypothesis is that macrophage-derived netrin-1 is a pathological signal capable of fueling MMP activation in vascular smooth muscle cells (VSMC) and the disruption of this cross-talk mechanism protects against pathological vascular remodeling in AAA. Our rationale is based on important observations made during K99/R00 award that the absence of netrin-1 in hematopoietic cells (Ntn1-/-) protects against AAA development and elastin fragmentation. Single cell RNA sequencing revealed that netrin-1 was harbored in transmural macrophages. Importantly, RNA sequencing of WT and Ntn1-/- aortas identified that MMP3 was downregulated in the VSMC in netrin-1-deficient mice. In our specific aims, will use novel mouse models of tissue-specific or conditional deletion of netrin-1 in macrophages, deletion of MMP3 and neogenin (the receptor of netrin-1) in VSMC to determine how this guidance cue orchestrates a series of events that lead to sustained ECM degradation by fueling the supply of catalytic enzymes to the abdominal tissue. The proposed research is innovative because we investigate the role netrin-1 in mediating cross-talk startegies and deleterious vascular remodeling, a heretofore-unexamined mechanism in AAA. Upon conclusion, we will understand the role of netrin-1 in synchronizing ECM damage via complex mechanisms in AAA. This contribution is significant since we will test whether targeting netrin-1 after AAA is established (inducible deletion murine models) can reverse the degradation of the ECM and prevent rupture. In this translational approach, our data will pave the way for the development of promising preventive therapeutic strategies aimed at targeting netrin-1 or antagonizing its signaling events to prevent AAA.