Isoprenoid Biology in Asthma: Proof-of-Principle and Method Development

项目摘要 我们已经发现甲羟戊酸（MA）途径的脂质代谢产物（称为类异戊二烯）在介导 哮喘疾病模型中的2型炎症。这一发现是新颖的，并出现在以前的工作 在我的K 08奖中完成，并建立了MA通路作为过敏性嗜酸性粒细胞炎症的组成部分 哮喘病我们的初步数据表明，过量的类异戊二烯分子池， 法尼基焦磷酸（FPP）和香叶基香叶基-PP（GGPP）显著增强白细胞介素-13诱导的STAT 6 体外人气道上皮细胞的活化和嗜酸性粒细胞趋化因子-2和-3的产生， 哮喘中的Th 2/2型炎症此外，用HMG-CoA还原酶抑制FPP和GGPP合成 抑制剂（他汀类），在类异戊二烯上游合成MA的酶，抑制IL-13诱导的嗜酸性粒细胞趋化因子 生产和胞外分泌。嗜酸性粒细胞趋化因子是嗜酸性粒细胞募集到 我们的研究结果表明，高水平的气道类异戊二烯介导和促进2型嗜酸性粒细胞增多， 气道炎症此外，我们使用哮喘小鼠模型的体内数据证实了 MA通路介导过敏性嗜酸性粒细胞炎症。消耗MA，因此 下游代谢物FPP和GGPP显著抑制肺和气道嗜酸性粒细胞增多。虽然这些数据 提示了它们在疾病发病机制中的作用，但它们限于人气道上皮细胞培养物， 小鼠哮喘模型。通过R 03的建议，我们希望确定类异戊二烯在人类疾病中的作用 并最终确定气道粘膜类异戊二烯的过量水平是否与持续气道炎症的程度相关 哮喘中的嗜酸性粒细胞炎症。因此，为了解决这一知识差距，我们假设，过度 气道上皮类异戊二烯的水平通过进一步诱导2型嗜酸性粒细胞炎症而增强体内2型嗜酸性粒细胞炎症 上皮细胞JAK/STAT 6磷酸化。我们将通过两个具体目标来解决这个假设：（1）确定是否 高水平外源性气道类异戊二烯增加体内嗜酸性气道炎症。(2)来验证 使用专门的质谱法测量气道和肺类异戊二烯的定量方法， 现有的动物和人体组织。实现这些目标将建立一个原则证明， 体内类异戊二烯在疾病发病机制中起作用，最重要的是，提供了必要的工具， 在未来的R 01资助申请中将该技术应用于人类哮喘患者。

PROJECT SUMMARY We have discovered a role for the mevalonate (MA) pathway lipid metabolites known as isoprenoids in mediating type 2 inflammation in asthma disease models. This finding is novel and emerges from work previously accomplished in my K08 award, and establishes the MA pathway as integral to allergic eosinophilic inflammation in asthma. Our preliminary data show that excess pools of the isoprenoid molecules known as farnesylpyrophosphate (FPP) and geranylgeranyl-PP (GGPP) markedly augment interleukin-13-induced STAT6 activation and eotaxin-2 and -3 production in human airway epithelial cells in vitro, key molecular pathways in Th2/type 2 inflammation in asthma. Further, inhibition of FPP and GGPP synthesis with HMG-CoA reductase inhibitors (‘statins’), the enzyme that synthesizes MA upstream of the isoprenoids, inhibits IL-13-induced eotaxin production and extracellular secretion. The eotaxins being a major chemokine for eosinophil recruitment into airway tissues, our results suggest that high levels of airway isoprenoids mediate and promote type 2 eosinophilic airway inflammation. Furthermore, our in vivo data using mouse models of asthma, confirm the critical role of the MA pathway in mediating allergic eosinophilic inflammation. Depleting MA pharmacologically, and therefore the downstream metabolites FPP and GGPP, significantly inhibits lung and airway eosinophilia. While these data are suggestive of their role in disease pathogenesis, they are limited to human airway epithelial cell culture and mouse models of asthma. Via this R03 proposal, we wish to establish the role of isoprenoids in human disease and ultimately determine if excess levels of airway mucosal isoprenoids correlate with degree of persistent airway eosinophilic inflammation in asthma. Therefore to address this gap in knowledge, we hypothesize that excess levels of airway epithelial isoprenoids enhance type 2 eosinophilic inflammation in vivo by further inducing epithelial JAK/STAT6 phosphorylation. We will address this hypothesis via two specific aims: (1) To determine if high levels of exogenous airway isoprenoids augment eosinophilic airway inflammation in vivo. (2) To validate a quantitative method of measuring airway and lung isoprenoids using specialized mass spectrometry in pre- existing animal and human tissues. Accomplishing these goals will establish the proof-of-principle that excess isoprenoids in vivo play a role in disease pathogenesis, and most importantly, provide the tools necessary to apply this technology to human asthmatics in future grant R01 grant applications.