Gene-Environment Interactions with Ozone and Non-atopic Asthma

项目概要 流行病学研究提供的证据表明，臭氧 (O3) 暴露与疾病的发生有关 哮喘，特别是非特应性（非过敏性）亚型。这些发现得到了临床研究的支持 研究表明，环境中的 O3 暴露与非特应性儿童的嗜酸粒细胞性气道炎症有关。 实验室研究表明，接触 O3 会导致非人类粘液细胞化生/增生 灵长类动物、大鼠和小鼠。这包括我们小组的最新结果，证明经典近交系 暴露于 0.8 ppm O3（4 小时/天）9 天的小鼠品系会出现嗜酸性粒细胞性气道炎症 另外还有粘液细胞增生。因此，三个物种和人类的数据提供了强有力的理由 旨在了解 O3 ® 非特应性哮喘关联的潜在机制的研究。 我们采用遗传学方法来解决机制问题。我们调查了来自协作交叉的菌株 (CC) 小鼠群体，一组新的重组近交品系，并鉴定出一个品系 CC002，该品系 在反复暴露于 O3 后表现出比任何其他菌株更高水平的嗜酸性粒细胞炎症 迄今为止已测试。 O3 暴露的 CC002 小鼠也出现粘液细胞化生和气道过度增生。 反应性（AHR），哮喘的另外两种标志性表型。因此，CC002提供了一种新的遗传模型 我们可以利用它来确定 O3 诱导的非特应性哮喘关联的潜在机制。在 第一个目标，我们将检验以下假设：CC002 对 O3 暴露的夸大反应是由于 通过警报素调节上皮信号传导失调，进而刺激 2 型先天淋巴细胞 (ILC2)。我们 将确定暴露于 O3 的上皮源性先天细胞因子（IL-1a/b、IL-25、IL-33、TSLP）是否增加 CC002 小鼠与无反应品系相比，如果这些细胞因子的中和减弱了 O3 诱导的 气道炎症和 AHR。接下来，我们将确定 O3 中 ILC2 数量和激活是否增加- 暴露的 CC002 小鼠，如果 ILC2 耗竭或 ILC2 衍生细胞因子（IL-5、IL-13）抑制改善 O3 在 CC002 小鼠中诱导气道炎症和 AHR。全面表征分子 为了了解上皮细胞、ILC2 和其他白细胞对 O3 的反应，我们将进行单细胞 RNA 测序。使用 通过这种创新而强大的方法，我们将量化基因表达和细胞组成的差异 /- O3，菌株内部和菌株之间。我们还将通过测试来检查 CC002 响应的特异性 该菌株是否对其他暴露表现出过度反应，包括内毒素、香烟烟雾、 和屋尘螨过敏原。在第二个目标中，我们将确定使 CC002 敏感的遗传位点 O3。我们将进行数量性状基因座作图，以确定含有 CC002 等位基因的染色体区域 与 O3 敏感性相关，然后进行生物信息分析，以确定高优先级候选基因 每个基因座。总的来说，我们的工作将揭示 O3 暴露与 非特应性哮喘表型的发展并确定潜在的治疗目标途径。

PROJECT SUMMARY Epidemiologic studies have provided evidence that ozone (O3) exposure is associated with the development of asthma, in particular the non-atopic (non-allergic) sub-type. These findings are supported by clinical studies showing that ambient O3 exposure is associated with eosinophilic airway inflammation in non-atopic children. Laboratory studies have shown that O3 exposure causes mucous cell metaplasia/hyperplasia in non-human primates, rats and mice. This includes recent results from our groups demonstrating that classical inbred strains of mice exposed to 0.8 ppm O3 (4 hours/day) for 9 days develop eosinophilic airway inflammation in addition to mucous cell hyperplasia. Thus, data in three species and humans provide strong rationale for studies geared towards understanding the underlying mechanisms of the O3 ® non-atopic asthma association. We take a genetic approach to the question of mechanism. We surveyed strains from the Collaborative Cross (CC) mouse population, a new panel of recombinant inbred strains and identified one strain, CC002, that exhibited much higher levels of eosinophilic inflammation after repeated O3 exposure than any other strain tested to date. O3 exposed CC002 mice also developed mucous cell metaplasia and airway hyper- responsiveness (AHR), two other hallmark phenotypes of asthma. Thus, CC002 provides a new genetic model that we can exploit to identify mechanisms underlying the of O3-induced non-atopic asthma association. In the first Aim, we will test the hypothesis that CC002’s exaggerated response to O3 exposure are due to dysregulated epithelial signaling via alarmins that in turn stimulates type 2 innate lymphoid cells (ILC2s). We will determine if epithelial-derived innate cytokines (IL-1a/b, IL-25, IL-33, TSLP) are increased in O3-exposed CC002 mice compared to non-responder strains, and if neutralization of these cytokines attenuates O3-induced airway inflammation and AHR. Next, we will determine if ILC2 numbers and activation are increased in O3- exposed CC002 mice, and if depletion of ILC2s or inhibition of ILC2-derived cytokines (IL-5, IL-13) ameliorates O3-induced airway inflammation and AHR in CC002 mice. To comprehensively characterize molecular responses to O3 in epithelia, ILC2s, and other leukocytes, we will perform single cell RNA-sequencing. Using this innovative and powerful approach, we will quantify differences in gene expression and cellular composition +/- O3, both within and between strains. We will also examine the specificity of CC002’s response by testing whether this strain exhibits exaggerated responses to other exposures, including endotoxin, cigarette smoke, and house dust mite allergen. In the second aim, we will identify the genetic loci that render CC002 sensitive to O3. We will perform quantitative trait locus mapping to identify chromosomal regions harboring CC002 alleles associated with O3 sensitivity, followed by bioinformatic analyses to identify high priority candidate genes at each locus. In total, our work will reveal mechanisms underlying the association between O3 exposure and the development of non-atopic asthma phenotypes and identify potential pathways to target therapeutically.