FLI1 in Pulmonary Arterial Hypertension

摘要肺动脉高压(PAH)是一种罕见且破坏性的疾病，可导致肺动脉高压。 重塑，右心衰竭和死亡。虽然有FDA批准的治疗方法，但没有一种是治愈的。它有 多年来，人们已经认识到生长因子，如血小板衍生生长因子和成纤维细胞生长 因子，通过酪氨酸激酶受体促进PAH的肺血管重构。伊马替尼，一种 非特异性酪氨酸激酶抑制剂在PAH动物模型和几个病例报告中的应用前景 演示了伊马替尼对PAH的治愈作用。伊马替尼治疗PAH的III期临床试验显示 一些患者的运动能力有所改善，但没有获得FDA的批准，因为该药物 耐受性很好。我们试图了解伊马替尼在PAH中作用的新机制。在初步数据中，我们 给表达人类突变的小鼠服用伊马替尼，已知这种突变会导致可遗传的PAH (骨形态发生受体2型，BMPR2)，并测试血浆蛋白质组学的变化作为一种新的方法 以一种可以转化为人类的方式检测关键的药物效应，可能会带来机械性的洞察力。 伊马替尼改变了血浆中的几种蛋白质，其中Friend白血病病毒整合1(FlI1)改变最多 显著改变了蛋白质。Fl1是一种转录因子，其功能在c-Abl结合后增强 伊马替尼。有趣的是，FLI1缺乏被很好地描述为在皮肤血管病变中起作用 硬皮病患者，这是一种与PAH密切相关的疾病。目前尚不清楚FLI1缺乏是否起到了作用 然而，在PAH中。我们使用伊马替尼作为一种工具来了解肺血管的机制。 PAH的功能障碍，并发现FLI1可能发挥关键作用。我们最重要的假设是，FLI1 缺乏通过破坏内皮细胞屏障功能促进PAH的发展 FLI1的修复将恢复内皮功能，改善PAH。我们提出以下目标： 检验这一假说：目的1.检验PAH中内皮屏障功能受损的假说 经伊马替尼暴露增加的FLI1表达可恢复PAH的内皮功能。我们将使用 培养的BMPR2或对照内皮细胞加或不加伊马替尼和/或Fl1 siRNA以测试屏障功能 以及FLI1在调节内皮屏障功能中的作用。目的2.检验FLI1缺乏症的假设 是PAH的啮齿动物模型，可增强PAH啮齿动物模型的肺血管疾病，并且 过表达FLI1可以预防啮齿动物的PAH。这一目标将产生两个小鼠模型：可诱导的全局FLI1 基因敲除和诱导的FLI1的全局过表达。我们将确定这些模型是加剧还是改进 一种公认的啮齿动物PAH模型，SUGEN+低氧，并在这些模型中测试肺血管渗漏。这 提案将产生必要的工具来研究FlI1在多环芳烃中的作用。从长远来看，这项工作将得到发展 针对这种罕见和高度病态的疾病的新的、耐受性良好的疾病修改疗法。

Pulmonary arterial hypertension (PAH) is a rare and devastating disease resulting in pulmonary arterial remodeling, right heart failure and death. While there are FDA-approved therapies, none is curative. It has been recognized for years that growth factors, such as platelet-derived growth factor and fibroblast growth factor, act through tyrosine kinase receptors to promote pulmonary vascular remodeling in PAH. Imatinib, a non-specific tyrosine kinase inhibitor showed promise in animal models of PAH and several case reports demonstrated cures of PAH with imatinib. A Phase III clinical trial of imatinib in PAH showed marked improvement in exercise capacity in some patients but did not receive FDA approval because the drug was not well tolerated. We sought to understand novel mechanisms of imatinib effect in PAH. In preliminary data, we administered imatinib to mice that express a human mutation that is known to cause heritable forms of PAH (bone morphogenetic receptor type 2, BMPR2) and tested changes in plasma proteomics as a novel way of detecting key drug effects in a manner that could be translated to humans and may lend mechanistic insight. imatinib altered several proteins in the plasma with Friend leukemia virus integration 1 (Fli1) being the most significantly changed protein. Fli1 is a transcription factor whose function is increased after c-Abl engagement by imatinib. Interestingly, Fli1 deficiency is well described to play a role in the vasculopathy of the skin of patients with scleroderma, a condition closely associated with PAH. it is unknown if Fli1 deficiency plays a role in PAH however. We have used imatinib as a tool to understand mechanisms of pulmonary vascular dysfunction in PAH and uncovered that Fli1 may play a key role. Our overarching hypothesis is that Fli1 deficiency contributes to PAH development through disruption of endothelial barrier function and that restoration of Fli1 will restore endothelial function and improve PAH. We propose the following aims to test this hypothesis: Aim 1. Test the hypothesis endothelial barrier function is impaired in PAH and that increased Fli1 expression through imatinib exposure restores endothelial function in PAH. We will use cultured BMPR2 or control endothelial cells with and without imatinib and/or Fli1 siRNA to test barrier function and the role of Fli1 in regulating endothelial barrier function. Aim 2. Test the hypothesis that Fli1 deficiency is a rodent model of PAH, enhances pulmonary vascular disease in a rodent model of PAH and that Fli1 overexpression prevents rodent PAH. This aim will generate two mouse models: inducible global Fli1 knockout and inducible global overexpression of Fli1. We will determine these models exacerbate or improve an accepted rodent PAH model, Sugen+Hypoxia, and test for pulmonary vascular leak in these models. This proposal will generate necessary tools to study the role of FLI1 in PAH. In the long term, this work will develop novel, well-tolerated disease modifying therapies for this rare and highly morbid disease.