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

项目总结 我们已经发现甲氧戊酸(MA)途径脂代谢产物异戊二烯在调节 哮喘模型中的2型炎症。这一发现是新奇的，在以前的工作中出现过。 在我的K08奖项中完成，并将MA途径确立为过敏性嗜酸性炎症不可或缺的一部分 得了哮喘。我们的初步数据显示，过剩的类异戊二烯分子池被称为 金合欢基焦磷酸(FPP)和香叶基香叶基-PP(GGPP)显著增强IL-13诱导的STAT6 人呼吸道上皮细胞体外激活和嗜酸性粒细胞趋化因子-2和-3的产生 哮喘中的Th2/2型炎症。此外，HMG-CoA还原酶抑制FPP和GGPP的合成 抑制剂(他汀类药物)是合成类异戊二烯上游MA的酶，它抑制IL-13诱导的嗜酸性粒细胞趋化蛋白 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 我们的结果表明，高水平的呼吸道类异戊二烯调节并促进了2型嗜酸性粒细胞。 呼吸道发炎。此外，我们使用哮喘小鼠模型的体内数据证实了 MA途径在介导过敏性嗜酸性炎症中的作用。从药理上消耗MA，因此 下游代谢产物FPP和GGPP显著抑制肺和呼吸道嗜酸性粒细胞增多。虽然这些数据 提示它们在疾病发病机制中的作用，它们仅限于人类呼吸道上皮细胞培养和 哮喘的小鼠模型。通过R03提案，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程度相关 哮喘患者的嗜酸性炎症。因此，为了解决这一知识差距，我们假设 呼吸道上皮异戊二烯水平通过进一步诱导体内2型嗜酸性粒细胞炎症 上皮性JAK/STAT6磷酸化。我们将通过两个具体目标来解决这一假设：(1)确定 体内高水平的外源性类异戊二烯可增加嗜酸性气道炎。(2)验证 特效质谱学定量测定哮喘前期患者呼吸道和肺内异戊二烯的方法 现存的动物和人类组织。实现这些目标将建立一个原则证明，即 体内的类异戊二烯在疾病的发病机制中发挥作用，最重要的是，提供了必要的工具来 在未来的R01拨款申请中，将这项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.