Reactive Oxygen Species in Vascular Disease

 描述（由申请方提供）：右心室（RV）衰竭是肺动脉高压（PAH）患者死亡的主要原因。缺氧诱导的PAH是导致心力衰竭的常见疾病形式。对病理机制的认识不足是针对该疾病的临床方法的障碍，该疾病通常与快速和侵袭性血管重塑、丛状病变（PL）形成和RV衰竭相关。来自NADPH氧化酶（Nox）的活性氧（ROS）与PAH有关，先前的数据支持Nox 2在肺血管内皮（EC）增殖中的作用。然而，尽管它在肺血管壁中表达，但在PAH中没有Nox 1的信息。重要的是，Nox 1在血管壁增厚和PL形成中的功能作用完全未知。我们提出了一个新的作用，Nox 1在促进增殖和血管重塑通过Gremlin 1，骨形态发生蛋白的拮抗剂。这一假设是基于最近Gremlin 1与PAH的相关性以及我们支持Nox 1介导的Gremlin 1在人肺动脉内皮细胞（HPAEC）增殖中表达的初步数据。事实上，任何氮氧化物在介导EC Gremlin 1的上游和下游介质中发挥的作用，包括音刺猬和CREB，是完全未知的。我们先前的目标导致开发高选择性和有效的Nox 1抑制剂。这种抑制剂，以及其他分子遗传学技术，允许识别多个新的途径，涉及Gremlin 1缺氧诱导的PAH。我们将检验核心假设，即Nox 1传播Gremlin 1介导的信号，从而促进缺氧诱导的PAH和RV衰竭。这将通过解决以下目标来测试：（1）在缺氧条件下，探究Nox 1的表达及其对人肺内皮细胞增殖中的ROS产生和Gremlin 1介导的信号传导的贡献;（2）确定特异性Nox 1抑制剂是否渗透并靶向缺氧诱导的内皮ROS信号传导和Gremlin 1表达，并减弱PAH小鼠模型中的血流动力学;以及（3）确定Nox 1抑制剂的雾化是否预防和/或逆转血管闭塞性PAH大鼠模型中的RV衰竭。这种范式转变的建议揭示了Gremlin 1-Nox 1在PAH和RV失败中的新作用。该研究计划建立在令人信服的初步数据基础上，有望开辟血管生物学研究的新领域，并在概念和技术上具有创新性。从治疗的角度来看，递送一种新型的和高度特异性的Nox 1抑制剂以通过雾化破坏肺血管内皮中的这一通路，预计将成为新药物治疗的坚实基础。

 DESCRIPTION (provided by applicant): Right ventricular (RV) failure is the leading cause of death in patients with pulmonary arterial hypertension (PAH). Hypoxia-induced PAH is a common form of the disease leading to heart failure. A poor understanding of pathologic mechanisms presents a barrier to clinical approaches targeting the disease, which is often associated with rapid and aggressive vascular remodeling, plexiform lesion (PL) formation, and RV failure. Reactive oxygen species (ROS) from NADPH oxidases (Noxs) are implicated in PAH and previous data support a role for Nox2 in pulmonary vascular endothelial (EC) proliferation. However, despite its expression in the pulmonary vascular wall, no information exists for Nox1 in PAH. Importantly, a functional role for Nox1 in vascular wall thickening and PL formation is entirely unknown. We propose a novel role for Nox1 in promoting proliferation and vascular remodeling via Gremlin1, an antagonist of bone morphogenetic protein. This hypothesis is based on a recent association of Gremlin1 with PAH and our preliminary data supporting Nox1-mediated Gremlin1 expression in human pulmonary artery endothelial cell (HPAEC) proliferation. In fact, the role that any Nox plays in mediating upstream and downstream mediators of EC Gremlin1, including sonic hedgehog and CREB, is entirely unknown. Our previous aims led to development of a highly-selective and efficacious Nox1 inhibitor. This inhibitor, as well as other molecular genetic techniques, allows identification of multiple new pathways involving Gremlin1 in hypoxia-induced PAH. We will test the central hypothesis that Nox1 propagates Gremlin1-mediated signaling, thereby promoting hypoxia- induced PAH and RV failure. This will be tested by addressing the following aims: (1) To interrogate the expression of Nox1 and its contribution to ROS production and Gremlin1- mediated signaling in human pulmonary endothelial cell proliferation under hypoxic conditions; (2) To determine whether specific Nox1 inhibitor permeates and targets hypoxia-induced endothelial ROS signaling and Gremlin1 expression and attenuates hemodynamics in a mouse model of PAH; and (3) To determine whether aerosolization of Nox1 inhibitor prevents and/or reverses RV failure in a rat model of vascular occlusive PAH. This paradigm-shifting proposal uncovers a novel role for Gremlin1-Nox1 in PAH and RV failure. The research plan, built on compelling preliminary data, is expected to open up a new field of inquiry in vascular biology and is conceptually and technologically innovative. From a therapeutic standpoint, delivery of a novel and highly-specific Nox1 inhibitor to disrupt this pathway in the pulmonary vascular endothelium via aerosolization is expected to serve as a firm foundation for new drug therapies.