microRNA-25 attenuates allergic inflammation by altering airway smooth muscle phenotype and function

 描述(申请人提供)：体外研究已经证实，在转录和转录后机制所介导的炎症事件中，呼吸道平滑肌(ASM)细胞表现出表型可塑性，这些机制尚未完全阐明。MicroRNA(MiRNA)介导的基因沉默是一种基因表达的调节因子，研究miRNA在ASM中的功能有望开发基于miRNA的新的预后和治疗工具。我们研究的长期目标是确定决定哮喘ASM细胞表型的miRNA介导的基因沉默机制。我们的实验室首次表征了促炎刺激后ASM中miRNA的表达，并确定miR-25是调节ASM细胞可塑性的炎症反应的靶点。这项建议将验证miR-25的表达通过改变ASM表型来减轻过敏性哮喘发病机制的假设。在特定的目标1中，我们将使用一种独特的以平滑肌靶向miR-25表达的转基因小鼠模型来确定miR-25在过敏性炎症小鼠模型中的表达是否可以减轻高反应性、重塑和改变ASM收缩力量。这些小鼠将被用来评估miR-25在卵清蛋白敏化和激发的急性和慢性模型后对AHR、重塑和ASM收缩的影响。在特定的目标2中，我们将通过评估增殖标记物和有丝分裂信号通路来研究在急性和慢性卵清蛋白敏化和攻击后，在体内平滑肌靶向miR-25表达在ASM质量增加中的作用，以解决这一miR-25功能的分子机制。在特定的目标3中，我们将通过miR-25的获得和丢失功能研究来确定miR-25是否影响哮喘ASM细胞的表型，以及对miR-25介导的基因沉默的识别靶点的影响。这种独特的实验方法，再加上人类疾病细胞的相关性，将提供描述miR-25在肺中功能的机制数据，并成为开发针对哮喘miRNA的新治疗策略的关键一步。

 DESCRIPTION (provided by applicant): In vitro studies have established that airway smooth muscle (ASM) cells exhibit phenotypic plasticity in response to inflammatory events mediated by transcriptional and post-transcriptional mechanisms that have not been fully elucidated. microRNA (miRNA)-mediated gene silencing has emerged as an regulator of gene expression and studies of miRNA function in ASM hold promise for the development of novel miRNA-based tools for prognosis and therapy. The long-term goal of our studies is to identify the miRNA-mediated gene- silencing mechanisms determining ASM cell phenotype in asthma. Our laboratory was the first to characterize miRNA expression in ASM following a pro-inflammatory stimulus and identified miR-25 as a target of the inflammatory response that regulates plasticity of ASM cells. This proposal will test the hypothesis that expression of miR-25 attenuates allergic asthma pathogenesis by altering ASM phenotype. In Specific Aim 1, we will determine whether miR-25 expression in a mouse model of allergic inflammation attenuates hyperreactivity, remodeling and alters ASM contractile force using a unique transgenic mouse model of smooth muscle-targeted miR-25 expression. These mice will be used to assess the effects of miR-25 on AHR, remodeling and ASM contractility following acute and chronic models of ovalbumin-sensitization and challenge. In Specific Aim 2, we will study the effect of smooth muscle-targeted miR-25 expression on increased ASM mass in vivo following acute and chronic ovalbumin-sensitization and challenge by assessing proliferative markers and mitogenic signaling pathways to address the molecular mechanisms underlying this miR-25 function. In Specific Aim 3, we will determine whether miR-25 affects the phenotype of asthmatic ASM cells using gain and loss of miR-25 function studies, as well as effects on identified targets of miR-25 mediated gene-silencing. This unique experimental approach, coupled with correlations in human diseased cells, will provide mechanistic data describing miR-25 function in the lung and be an essential step towards developing novel therapeutic strategies targeting miRNA in asthma.