Quercetin prevents progression of COPD lung disease by modulating Foxo3Aactivity

描述(申请人提供)：项目摘要：栎素，一种植物类黄酮，是一种有效的抗氧化剂和消炎剂。我们进行了临床前研究，评估了栎素治疗慢性阻塞性肺疾病(COPD)的适宜性，慢性阻塞性肺疾病(COPD)是美国第三大死因。我们发现，栎素可以减少肺部炎症、杯状细胞化生和肺气肿的进展，部分原因是通过增加呈现典型COPD特征的弹性酶/脂多糖暴露小鼠的脱乙酰基酶Sirt1的表达。我们的初步研究表明，弹性蛋白酶/脂多糖暴露的小鼠表现出核FOXO3a的减少，FOXO3a是一种转录因子，它负向调节炎症并提供对氧化应激的抵抗力。此外，我们发现，保持COPD呼吸道上皮细胞表型特征的COPD气道上皮细胞也显示出Sirt1和FOXO3a的核水平降低。感染人类鼻病毒(RV)是COPD恶化的常见原因，进一步降低了核Sirt1和FOXO3a的水平。我们的初步研究还表明，在弹性酶/脂多糖处理的小鼠中，栎素促进FOXO3a到细胞核的移位。此外，对COPD上皮细胞培养的处理减少了IL-8的表达和粘液化生，同时恢复了核FOXO3a的水平。最后，在弹性酶/脂多糖小鼠和COPD上皮细胞中，栎素改善了RV攻击后的病毒清除。总体目标是阐明在慢性阻塞性肺疾病模型中，栎素调节核FOXO3a和Sirt1水平的机制，从而减少炎症、杯状细胞化生和增加病毒清除。为实现这一目标，我们提出了以下具体目标。1.明确了槲皮素调节COPD模型FOXO3a活性、抑制IL-8等趋化因子过度表达、减轻肺部炎症的机制。FOXO3a的核转位受磷酸化和乙酰化的调节。我们检验了以下假设：1)槲皮素处理阻断Akt激酶活性，从而增加FOXO3a向细胞核的移位；2)Quercetin诱导Sirt1去乙酰化核FOXO3a，阻止Akt从核输出的磷酸化；以及3)Sirt1和FOXO3a共同阻断NF-κB与CxCL-1、2、5和8启动子的结合，从而减轻细胞因子的表达和肺部炎症。2.探讨槲皮素抑制慢性阻塞性肺疾病气道杯状细胞化生的机制。我们的实验数据表明，在COPD细胞和COPD小鼠模型中，EGFR的异常激活。我们将验证假设：1)栎素诱导的核FOXO3a正向调节E-钙粘蛋白的表达，从而将EGFR隔离在上皮细胞的基底外侧表面；2)槲皮素直接抑制EGFR的活性；3)通过恢复Sirt1的水平，Quercetin抑制基质金属蛋白酶(MMP)的表达，从而减少EGF配体的可获得性；以及4)EGFR活性降低减少粘蛋白基因的表达，防止杯状细胞化生。3.确定槲皮素促进COPD呼吸道病毒清除的机制。我们将测试假设：1)氧化应激诱导自噬小体的形成和积累，为病毒复制提供平台；2)轮状病毒感染，通过其对Akt和CBP/p300的影响，减少核FOXO3a和第二阶段抗氧化酶的表达，放大COPD细胞中的紊乱；以及3)槲皮素通过调节FOXO3a和Sirt1恢复抗氧化酶的表达，减少自噬和增加病毒清除。这些研究的完成将为了解栎素在慢性阻塞性肺疾病中减少呼吸道炎症、杯状细胞化生和病毒清除的机制提供重要的见解。这些研究需要确定作为COPD肺部疾病管理的替代辅助药物的槲皮素的适宜性。

DESCRIPTION (provided by applicant): Project Summary Quercetin, a plant flavonoid is a potent antioxidant and anti-inflammatory agent. We have performed preclinical studies assessing the suitability of quercetin in the treatment of chronic obstructive pulmonary disease (COPD), a third leading cause of death in the U.S. We showed that quercetin reduces lung inflammation, goblet cell metaplasia and progression of emphysema, in part by increasing expression of the deacetylase Sirt1 in elastase/LPS-exposed mice displaying typical features of COPD. Our pilot studies indicate that elastase/LPS-exposed mice show reduced nuclear FOXO3a, a transcription factor that negatively regulates inflammation and provide resistance to oxidative stress. Further, we found that COPD airway epithelial cells which maintain the phenotypic characteristics of the COPD airway epithelium also show reduced nuclear levels of Sirt1 as well as FOXO3a. Infection with human rhinovirus (RV), a common cause of COPD exacerbations further reduced nuclear Sirt1 and FOXO3a levels. Our pilot studies also show that quercetin promotes translocation of FOXO3a to the nucleus in elastase/LPS-treated mice. Further, quercetin treatment of COPD epithelial cell cultures reduced IL-8 expression and mucus metaplasia, while restoring nuclear FOXO3a levels. Finally, quercetin improved viral clearance after RV challenge in both elastase/LPS mice and COPD epithelial cells. The overall goal is to elucidate the mechanisms by which quercetin modulates nuclear FOXO3a and Sirt1 levels, thereby decreasing inflammation, goblet cell metaplasia and augment viral clearance in COPD models. To accomplish this goal, we propose the following specific Aims. 1. Determine the mechanisms by which quercetin modulates FOXO3a activity and inhibits overexpression of IL-8 and other chemokines and reduces lung inflammation in COPD models. Nuclear translocation of FOXO3a is regulated by phosphorylation and acetylation. We test the hypotheses that 1) quercetin treatment blocks Akt kinase activity, thereby increasing FOXO3A translocation to the nucleus; 2) quercetin-induced Sirt1 deacetylates nuclear FOXO3a, preventing phosphorylation by Akt export from the nucleus; and 3) Sirt1 and FOXO3a together block NF-κB binding to the CXCL-1, 2, 5 and 8 promoter, thereby attenuating cytokine expression and lung inflammation. 2. Examine the mechanisms by which quercetin decreases goblet cell metaplasia in COPD airways. Our pilot data indicate aberrant activation of EGFR in COPD cells as well as in COPD mouse model. We will test the hypotheses that 1) quercetin-induced nuclear FOXO3a positively regulates expression of E-cadherin, which sequesters EGFR at the epithelial cell basolateral surface; 2) quercetin directly inhibits EGFR activity; 3) quercetin, by restoring Sirt1 levels, inhibits matrix metalloproteinase (MMP) expression, thereby decreasing the availability of EGF ligands; and 4) reduced EGFR activity decreases expression of mucin genes, preventing goblet cell metaplasia. 3. Determine the mechanisms by which quercetin increases viral clearance in COPD airways. COPD exacerbations are associated with increased oxidative stress We will test the hypotheses that: 1) oxidative stress induces formation and accumulation of autophagosomes, providing a platform for viral replication; 2) RV infection, via its effects on Akt and CBP/p300, decreases nuclear FOXO3a and phase II antioxidant enzyme expression, amplifying derangements present in COPD cells; and 3) quercetin restores antioxidant enzyme expression by modulation of FOXO3a and Sirt1, decreasing autophagy and increasing viral clearance. Completion of these studies will provide important insights into mechanisms by which quercetin decreases airway inflammation, goblet cell metaplasia and viral clearance in chronic obstructive lung disease. These studies are required to determine the suitability of quercetin as an alternative complimentary medicine in the management of COPD lung disease.