Nur77: Novel Mechanistic Insights and Activation in COPD

通常由吸烟引起的慢性阻塞性肺疾病(COPD)的患病率正在上升 预计到本世纪中叶，它将成为全球主要的死亡原因。可用的治疗方法可提供 只是短期受益，并不能阻止COPD的必然进展。即使戒烟，在戒烟后 最早的阶段，提供的好处有限。因此，迫切需要新的机械疗法来阻止病情发展。 需要的。慢性阻塞性肺疾病的病理生理包括支气管炎和重塑，合并间隔 炎症相关的氧化应激和蛋白酶分泌导致的破坏/肺气肿。 炎症诱导的呼吸道上皮细胞(AECs)凋亡也被认为是导致呼吸道疾病的原因之一。 改建。基于有希望的初步发现，拟议的研究将检验新的假设，即 孤儿核激素受体Nur77的激动剂激活可能对COPD有有益的影响。 初步结果显示，COPD患者的AECs和肺，以及吸烟小鼠的肺 烟雾(CS)诱导的COPD细胞中Nur77的表达明显下调。我们还发现，Nur77 基因敲除(KO)可加重CS诱导的小鼠炎症和肺损伤，提示KO具有保护作用 内源性NUR77。我们测试了经典的Nur77激动剂环孢素B和 发现它改善了CS诱导的小鼠肺损伤和炎症，导致我们假设Nur77 激动剂可能在慢性阻塞性肺疾病的治疗中有用。我们的计算机研究结果表明，Nur77表现出双重的(经典的和 另一种)配体结合位点。还没有确定任何替代位点的配体，但评估了任何潜在的 激活它的有益效果我们在计算机模拟中使用，以确定一种新的化合物，在体外研究 证明了它与Nur77替代位点结合，并发现它是激活Nur77的激动剂 体外转录活性高于胞孢素B的CS提取物可诱导血管内皮细胞和II型 肺内皮细胞发生凋亡，这是一条可能导致COPD的途径。Nur77本地化到 已知线粒体可触发细胞凋亡，这使我们假设CS提取物正在诱导细胞运动 Nur77从细胞核到细胞质，再到线粒体。我们的初步数据显示，我们的小说 替代位点Nur77激动剂通过锚定Nur77逆转COPD相关细胞质定位 其靶向反应元件位于细胞核内，从而减轻肺内皮细胞的炎症和凋亡。基座 根据这些新的发现，目的是：1：确定内源性抑制核和总 在COPD中出现的Nur77活性促进了疾病的进展和严重程度。2：测试是否激活Nur77 改善COPD的严重程度和进展，并促进肺内皮细胞的凋亡。我们将实现这些目标 目的：用我们的新型有效的Nur77体外处理健康对照组和COPD患者的人AEC 激动剂，并在小鼠中测试其效果±转基因全局或AEC特异性Nur77缺失，在标准CS- 诱导小鼠慢性阻塞性肺疾病模型。这一结果将阐明受体Nur77在COPD中的保护作用，以及 可能会将其确定为特定激动剂治疗一种广泛的致命疾病的有前途的新治疗靶点。

Chronic obstructive pulmonary disease (COPD), usually caused by cigarette smoking, is rising in prevalence and is predicted to become the leading cause of death worldwide by mid-century. Available treatments provide only short-term benefit, and fail to stop COPD’s inexorable progression. Even smoking cessation, after the earliest stages, provides limited benefit. New mechanistic therapies to halt progression are thus urgently needed. COPD pathophysiology includes bronchial inflammation and remodeling, combined with septal destruction/emphysema driven by inflammation-associated oxidative stress and protease secretion. Inflammation-driven apoptosis of airway epithelial cells (AECs) is also thought to contribute to airway remodeling. Based on promising preliminary findings, the proposed research will test the novel hypothesis that agonist activation of the orphan nuclear hormone receptor Nur77 may have beneficial effects in COPD. Preliminary findings revealed that AECs and lungs of COPD patients and also lungs of mice with cigarette smoke (CS)-induced COPD exhibit marked downregulation of Nur77 expression. We also found that Nur77 knockout (KO) exacerbates CS-induced inflammation and lung damage in mice, suggesting a protective role of endogenous Nur77. We tested the effects of treatment with the classical Nur77 agonist cytosporone B and found it ameliorated CS-induced lung damage and inflammation in mice, leading us to hypothesize that Nur77 agonists may be useful in COPD therapy. Our in silico findings show that Nur77 exhibits dual (classical and alternate) ligand binding sites. No alternate site ligand had been identified, but to assess any potential beneficial effects of activating it we used in silico modeling to identify a novel compound that in vitro studies demonstrated binds to the Nur77 alternate site, and found that it is an agonist that activates Nur77 transcriptional activity more effectively than cytosporone B. CS extract in vitro causes AECs and type ll pulmonary ECs to become apoptotic, a pathway that potentially contributes to COPD. Nur77 localization to mitochondria is known to trigger apoptosis, leading us to hypothesize that CS extract is inducing movement of Nur77 from the nucleus to cytoplasm and thence to the mitochondria. Our preliminary data show that our novel alternate site Nur77 agonist reverses such COPD-associated cytoplasmic localization by anchoring Nur77 to its target response elements in the nucleus, thus ameliorating inflammation and apoptosis of lung ECs. Based on these novel findings, the aims are to: 1: Determine whether endogenous suppression of nuclear and total Nur77 activity that occurs in COPD promotes disease progression and severity. 2: Test if activating Nur77 ameliorates COPD severity and progression and its contributing lung EC apoptosis. We will achieve these aims by treating human AECs of healthy controls and COPD patients in vitro with our novel, effective Nur77 agonist, and testing its effects in mice ± transgenic global or AEC-specific Nur77 deletion, in a standard CS- induced murine COPD model. The results will elucidate a protective role in COPD of the receptor Nur77, and may identify it as a promising new therapeutic target for specific agonists to treat a widespread fatal disease.