MicroRNA-10a in Airway Smooth Muscle and Asthma

项目总结 超过3亿人患有哮喘，其中许多是儿童。呼吸道平滑肌 (ASM)控制气道狭窄，在哮喘的发病机制中起着关键作用。 哮喘ASM过度增殖，分泌更多炎性细胞因子/趋化因子 而且可能会更容易收缩。ASM中的这些表型变化直接对呼吸道起作用 哮喘的主要特征是重塑和气道高反应性(AHR)。尽管 对ASM表型调控机制的广泛研究，没有单一基因或 已知通路控制多种ASM表型。因此，主干哮喘 治疗可以降低ASM的收缩能力(激动剂)或呼吸道炎症(糖皮质激素)， 而且目前还没有直接针对ASM增殖的治疗方法。MicroRNAs虽小但功能强大 基因调谐器：单个microRNA能够靶向多个基因，因此具有 有可能影响不同的细胞过程。我们最近确定miR-10a是一种高度ASM- 最丰富和最丰富的microRNA--占总microRNA的20%以上 在ASM中的表达。我们已报道miR-10a通过以下途径抑制ASM细胞的增殖 直接靶向PI3KCA--PI3K途径的中心成分。初步数据显示 MiR-10a还抑制了NFB信号转导，同时增加了2-肾上腺素能受体的表达 受体(2AR)-主要哮喘药物激动剂的靶标。重要的是，miR-10a 哮喘ASM细胞和炎性细胞因子的表达减少。基于这些 研究表明，我们假设miR-10a通过调节多种关键的ASM表型 抑制特定靶基因和该调控的扰动有助于 与哮喘的发展有关，并改变对哮喘治疗的反应。为了测试这一点 假设，我们提出了这个高度整合的项目，将活体小鼠模型， 原代ASM细胞的分子机制研究和人类遗传流行病学 哮喘人群。AIM 1将确定miR-10a是否通过抑制ASM来抑制AHR 增殖和趋化因子的分泌。目标2将调查miR-10a是否增加 通过抑制-2AR下调来保护支气管。目标3将确定关联和 MiR-10a和靶基因变异在哮喘及哮喘治疗反应中的作用。 这项研究的结果将确立miR-10a作为多个关键ASM的主调节因子 并将microRNA-10a确定为哮喘的新治疗靶点。

PROJECT SUMMARY Over 300 million people, many of them children, suffer from asthma. Airway smooth muscle (ASM) controls airway narrowing and plays a pivotal role in the pathogenesis of asthma. Asthmatic ASM becomes hyper-proliferative, secretes more inflammatory cytokines/chemokines and may be more contractile. These phenotypic changes in ASM contribute directly to airway remodeling and airway hyperresponsiveness (AHR)—cardinal features of asthma. Despite extensive studies on the regulatory mechanisms governing ASM phenotypes, no single gene or pathway is known to control multiple ASM phenotypes. Consequently, mainstay asthma therapies reduce either ASM contractility (-agonists) or airway inflammation (glucocorticoids), and there is no therapy that directly targets ASM proliferation. MicroRNAs are small yet powerful gene tuners: a single microRNA is capable of targeting a multitude of genes and thus has the potential to impact diverse cellular processes. We recently identified miR-10a as a highly ASM- enriched and the most abundant microRNA—accounting for more than 20% of total microRNA expression in the ASM. We have reported that miR-10a inhibits the proliferation of ASM cells by directly targeting PI3KCA--the central component of the PI3K pathway. Preliminary data indicate that miR-10a also suppresses NFB signaling while increasing the expression of 2-adrenergic receptor (2AR)—the target of mainstay asthma drug -agonists. Importantly, miR-10a expression is reduced in asthmatic ASM cells and by inflammatory cytokines. Based on these studies, we hypothesize that miR-10a regulates multiple critical ASM phenotypes via suppression of specific target genes and that perturbation of this regulation contributes to the development of asthma and alters response to asthma therapies. To test this hypothesis, we propose this highly integrative project that combines in vivo mouse models, molecular mechanistic studies in primary ASM cells, and genetic epidemiology in human asthma populations. Aim 1 will determine whether miR-10a inhibits AHR by suppressing ASM proliferation and chemokine secretion. Aim 2 will investigate whether that miR-10a augments bronchoprotection by inhibiting 2AR downregulation. Aim 3 will determine the association and function of miR-10a and target gene variants in asthma and in the response to asthma therapy. Results from this study will establish miR-10a as a master regulator of multiple critical ASM phenotypes and identify microRNA-10a as a novel therapeutic target for asthma.