ILC2 memory in asthma

摘要 非过敏性哮喘约占成人哮喘人口的30%，经常与 严重的哮喘。与过敏性哮喘不同，非过敏性哮喘的发病机制知之甚少。 嗜酸性炎症在非过敏性哮喘中很常见。环境因素是否会导致 嗜酸性炎症的发病机制尚不清楚。我们已经开发出一种哮喘的小鼠模型，通过 反复暴露于过敏原相关的PAMPs(病原体相关的分子模式)。ILC(先天 淋巴样细胞)从这个模型发展出一种PAMP特异性记忆，这种记忆可以用一种 3~15周后给予阈值下剂量的PAMP。基于广泛的初步结果，我们假设 反复接触PAMPS导致ILC记忆的形成，这构成了两个程序-a 基因抑制计划和准备计划。对先前激活的基因的抑制形成 记忆的遗传基础。这种抑制可以在没有PAMP的情况下防止主机损坏。这个 防备计划通过激活 Fhl2-ERK1/2-AP1途径，它下调先前标记的基因并诱导哮喘(图1)。我们 提出3个具体目标来检验这一假说。在目标1下，我们将研究过敏原和PAMP引起的哮喘 并检测过敏原和PAMP之间的交叉反应。我们将评估 ILC和模式识别受体在哮喘模型中的重要性。在目标2下，我们将澄清 ILC记忆的形成机制。我们将研究转录和表观遗传景观 过敏原和PAMP诱导的记忆ILCs及其随时间的持久性。ScRNA-seq和 来自记忆ILCS的ATAC-SEQ提示了抑制物Bach2和准备通路Fhl2的作用。 ERK1/2-FosB分别用于记忆诱导和回忆。我们将研究Fhl2、Bach2和FosB的作用 以一种功能丧失的方法。目标3将致力于人类国际法委员会的研究。我们将检查该表达式 对人类ILC中的抑制和准备程序基因进行克隆，并研究其诱导机制。 我们将研究非嗜酸性粒细胞记忆性ILC的频率及其对变应原和PAMP的反应 过敏性哮喘患者并建立其临床相关性。我们将使用公正和强大的基因组 方法，如RNA-seq和atac-seq，并利用创新的鼠标模型来测试 PAMP-引发ILC内存。我们将研究非过敏性嗜酸性哮喘的分子机制， 测试治疗策略，并利用哮喘的临床样本寻求建立人类相关性 病人。我们有必要的专业知识和工具来进行拟议的实验。这项提议将 产生改变范式的新知识和干预策略，这将有助于治疗非过敏性哮喘。

ABSTRACT Non-allergic asthma constitutes about 30% of the adult asthma population and is frequently associated with severe asthma. Unlike that of allergic asthma the mechanism of non-allergic asthma is poorly understood. Eosinophilic inflammation is common in non-allergic asthma. Whether environmental factors contribute to the pathogenesis of eosinophilic inflammation is unclear. We have developed a mouse model of asthma through repetitive exposure to allergen-associated PAMPs (Pathogen-associated Molecular Patterns). ILCs (innate lymphoid cells) from this model developed a PAMP-specific memory, which could be elicited with a subthreshold dose of the PAMP 3-15 weeks later. Based upon extensive preliminary results, we hypothesize that repetitive exposure to PAMPS leads to the formation of ILC memory, which constitutes two programs—a gene repression program and a preparedness program. The repression of previously activated genes forms the genetic basis for memory. This repression prevents host damage in the absence of the PAMPs. The preparedness program generates a rapid response to a subthreshold PAMP exposure through activation of the Fhl2-ERK1/2-AP1 pathway, which de-represses the previously marked genes and induces asthma (Fig. 1). We propose 3 specific aims to test this hypothesis. Under Aim 1 we will study allergen- and PAMP-elicited asthma and memory ILCs in mice and examine cross-reactivity among allergens and PAMPs. We will assess the importance of ILCs and the pattern recognition receptors in this asthma model. Under aim 2 we will elucidate the mechanism of formation of ILC memory. We will study the transcriptomic and epigenetic landscapes of allergen- and PAMP-induced memory ILCs and their persistence over time. The results from scRNA-seq and ATAC-seq from memory ILCs suggested a role for the repressor Bach2 and the preparedness pathway Fhl2- ERK1/2-Fosb for memory induction and recall, respectively. We will examine the role of Fhl2, Bach2 and FosB in a loss-of-function approach. Aim 3 will be devoted to human ILCs studies. We will examine the expression of the repression and preparedness program genes in human ILCs and study the mechanism of their induction. We will study the frequency of memory ILCs and their response to allergens and PAMPs in eosinophilic non- allergic asthmatic patients and establish their clinical correlation. We will employ unbiased and robust genomic approaches such as RNA-seq and ATAC-seq, and utilize innovative mouse models to test the novel concept of PAMP-elicited ILC memory. We will examine the molecular mechanism of non-allergic eosinophilic asthma, test therapeutic strategies, and seek to establish human relevance using clinical samples from asthmatic patients. We have the necessary expertise and tools to conduct the proposed experiments. The proposal will generate paradigm-shifting new knowledge and intervention strategies that will help treat non-allergic asthma.