MicroRNA-10a in Airway Smooth Muscle and Asthma

项目摘要 超过3亿人，其中许多是儿童，患有哮喘。气道平滑肌 (ASM)控制气道狭窄并在哮喘发病机制中起关键作用。 哮喘ASM过度增殖，分泌更多炎性细胞因子/趋化因子 并且可能更易收缩。ASM的这些表型变化直接导致气道炎症。 重塑和气道高反应性（AHR）-哮喘的主要特征。尽管 关于ASM表型调控机制的广泛研究，没有单一基因或 已知该途径控制多种ASM表型。因此， 治疗降低ASM收缩性（β-激动剂）或气道炎症（糖皮质激素）， 并且没有直接靶向ASM增殖的疗法。MicroRNA很小，但很强大 基因调谐器：单个microRNA能够靶向多个基因，因此具有 可能影响不同的细胞过程。我们最近发现miR-10a是一种高度ASM- 最丰富的microRNA-占总microRNA的20%以上 ASM中的表达式。我们已经报道了miR-10a通过以下方式抑制ASM细胞的增殖： 直接靶向PI 3 KCA-PI 3 K通路的中心成分。初步数据显示 miR-10 a还抑制NF κ B B信号传导，同时增加β 2-肾上腺素能受体的表达。 受体（β 2 AR）--主要哮喘药物β受体激动剂的靶点。重要的是，miR-10a 在哮喘ASM细胞中和通过炎性细胞因子降低表达。基于这些 研究中，我们假设miR-10a通过以下途径调节多种关键的ASM表型： 特异性靶基因抑制和这种调节的干扰有助于 哮喘的发展和改变对哮喘治疗的反应。为了验证这一 假设，我们提出了这个高度整合的项目，结合体内小鼠模型， 原代ASM细胞的分子机制研究和人类的遗传流行病学 哮喘人群目的1将确定miR-10a是否通过抑制ASM来抑制AHR 增殖和趋化因子分泌。目标2将研究miR-10a是否会增加 支气管保护作用通过抑制β 2 AR下调。目标3将确定关联， miR-10a和靶基因变异体在哮喘和哮喘治疗反应中的功能。 这项研究的结果将确立miR-10a作为多个关键ASM的主要调节因子 表型和鉴定microRNA-10a作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.