Reactive Oxygen Species in Vascular Disease

 描述(申请人提供)：右室衰竭是肺动脉高压(PAH)患者的主要死亡原因。缺氧性肺动脉高压是导致心力衰竭的一种常见疾病形式。对病理机制的认识不足阻碍了针对该病的临床治疗方法，这通常与快速和侵袭性的血管重塑、丛状病变(PL)形成和RV失败有关。NADPH氧化酶(NOXs)的活性氧物种(ROS)与PAH有关，以往的数据支持NOX2在肺血管内皮细胞(EC)增殖中的作用。然而，尽管Nox1在肺血管壁中表达，但在PAH中没有关于Nox1的信息。重要的是，Nox1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Nox1通过骨形态发生蛋白拮抗剂Gremlin1在促进增殖和血管重塑中的新作用。这一假说是基于最近Gremlin1与PAH的关联，以及我们的初步数据支持Nox1介导的Gremlin1在人肺动脉内皮细胞(HPAEC)增殖中的表达。事实上，任何NOx在EC Gremlin1的上下游调节因子中扮演的角色，包括Sonic Hedgehog和CREB，都是完全未知的。我们之前的目标是开发一种高选择性和有效的NOX1抑制剂。这种抑制物，以及其他分子遗传学技术，允许识别多个涉及Gremlin1在低氧诱导的PAH中的新途径。我们将验证中心假设，即Nox1传播Gremlin1介导的信号，从而促进低氧诱导的PAH和RV失败。这将通过以下目标进行测试：(1)询问低氧条件下人肺内皮细胞增殖中NOx1的表达及其对ROS产生和Gremlin1介导的信号转导的作用；(2)确定特定的Nox1抑制剂是否渗透并靶向低氧诱导的内皮ROS信号和Gremlin1的表达并减弱PAH小鼠的血流动力学；以及(3)确定雾化Nox1抑制剂是否可以预防和/或逆转血管闭塞性PAH大鼠模型的RV衰竭。这一范式转换的建议揭示了Gremlin1-Nox1在PAH和RV故障中的新角色。该研究计划建立在令人信服的初步数据基础上，预计将开辟血管生物学研究的新领域，在概念和技术上都是创新的。从治疗的角度来看，通过雾化提供一种新型的、高度特异的Nox1抑制剂来破坏肺血管内皮细胞的这一途径，有望为新药治疗奠定坚实的基础。

 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.