A clonal analysis of smooth muscle development in the mouse lung

描述(申请人提供)：摘要：在胚胎发育期间，肺的传导气道被一层收缩的平滑肌层包裹，该层保持张力并调节管子的扩张和收缩。呼吸道平滑肌调节失调和肥大是包括哮喘在内的出生后影响肺的严重疾病的一个重要特征。起源于气道平滑肌的信号在气道重塑和肥大细胞侵袭中起重要作用，从而导致过敏性哮喘患者的气道高反应性。哮喘的易感性与胎儿发育过程中出现的图案缺陷有关，这突显了在细胞分辨率上了解平滑肌肉发育的正常过程的必要性，以提供了解突变表型和疾病发病机制的框架。呼吸道平滑肌的发育和构型对于正常的肺功能是必不可少的，但人们对这种组织的细胞前体以及它们在发育过程中如何组装成平滑肌的发育潜力知之甚少。使用条件性Cre介导的重组技术，在肺发育过程中的特定时间对单个细胞进行荧光标记，并跟踪其后代的命运，这项建议中详细介绍的实验将确定祖细胞何时何地形成气道平滑肌，并将确定这些平滑肌前体细胞的发育潜力。然后，这种克隆标记技术将扩展到肺器官外植体，这将使标记事件可视化，并在培养过程中连续跟踪标记细胞及其后代。这些实验将提供对呼吸道平滑肌如何形成的细胞水平的理解，我希望从长远来看，这种理解将引导人们找到诊断和治疗哮喘和其他影响肺平滑肌谱系的疾病的新途径。 相关性：过敏性哮喘患者气道平滑肌肥大的细胞基础尚未完全了解。细胞迁移、诱导和细胞凋亡减少等其他因素可能在气道重塑中起关键作用，目前尚不清楚细胞增殖是否单独导致平滑肌层扩张。除了提供对正常平滑肌发育过程的清楚了解外，本提案中详细介绍的技术还可以扩展到定义导致哮喘模型中气道重塑的细胞事件，从而为疾病的诊断和治疗开辟新的途径。

DESCRIPTION (provided by applicant): Summary: During embryonic development the conducting airways of the lung are wrapped in a layer of contractile smooth muscle that maintains tone and regulates dilation and constriction of the tubes. Misregulation and hypertrophy of the airway smooth muscle is a key feature of serious diseases affecting the lung in postnatal life including asthma. Signals originating in the airway smooth muscle play an essential role in airway remodeling and mast cell invasion, resulting in the airway hyperresponsiveness observed in allergic asthma. A predisposition to asthma is associated with patterning defects that arise during fetal development, highlighting the need to understand the normal process of smooth muscle development at a cellular resolution to provide a framework for understanding mutant phenotypes and disease pathogenesis. The development and patterning of the airway smooth muscle is essential for proper lung function, yet little is known about the cell progenitors of this tissue, their developmental potential how they assemble into smooth muscle during development. Using conditional Cre-mediated recombination techniques to fluorescently mark single cells at defined times during lung development and follow the fate of their progeny, the experiments detailed in this proposal will identify when and where progenitor cells are specified to form airway smooth muscle, and will define the developmental potential of those smooth muscle progenitors. This clonal labeling technique will then be extended to lung organ explants, which will allow visualization of the marking event and continual tracking of the marked cell and its progeny during development in culture. These experiments will provide a cellular level understanding of how airway smooth muscle is formed, an understanding that I hope will lead in the long run to new avenues for diagnosis and treatment of asthma and other disease affecting smooth muscle lineages of the lung. Relevance: The cellular basis for airway smooth muscle hypertrophy in allergic asthma is not completely understood. Doubt has been cast on whether proliferation alone is responsible for the expansion of the smooth muscle layer, and other factors such as cell migration, induction, and decreased apoptosis may play key roles in airway remodeling. In addition to providing a clear understanding of the process of normal smooth muscle development, the techniques detailed in this proposal can be extended to define the cellular events responsible for airway remodeling in asthma models, thereby opening new avenues for the diagnosis and treatment of the disease.