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

 描述（由申请人提供）：体外研究已经确定，气道平滑肌（ASM）细胞对由尚未完全阐明的转录和转录后机制介导的炎症事件的反应表现出表型可塑性。microRNA（miRNA）介导的基因沉默已成为基因表达的调节因子，并且对ASM中miRNA功能的研究有望开发用于预后和治疗的新型基于miRNA的工具。我们研究的长期目标是确定在哮喘中决定ASM细胞表型的miRNA介导的基因沉默机制。我们的实验室是第一个在促炎刺激后表征ASM中miRNA表达的实验室，并将miR-25鉴定为调节ASM细胞可塑性的炎症反应的靶点。该提案将验证miR-25的表达通过改变ASM表型来减弱过敏性哮喘发病机制的假设。在具体目标1中，我们将使用平滑肌靶向miR-25表达的独特转基因小鼠模型，确定在过敏性炎症小鼠模型中miR-25表达是否减弱高反应性、重塑并改变ASM收缩力。这些小鼠将用于评估在卵清蛋白致敏和激发的急性和慢性模型后miR-25对AHR、重塑和ASM收缩性的影响。在特定目标2中，我们将通过评估增殖标志物和促有丝分裂信号通路来研究平滑肌靶向miR-25表达对急性和慢性卵清蛋白致敏和激发后体内ASM质量增加的影响，以解决miR-25功能的分子机制。在具体目标3中，我们将使用miR-25功能的获得和丧失研究以及对miR-25介导的基因沉默的已鉴定靶点的影响来确定miR-25是否影响哮喘ASM细胞的表型。这种独特的实验方法，加上人类患病细胞中的相关性，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的新治疗策略的重要一步。

 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.