Molecular mechanisms underlying upper airway patterning and tracheomalacia

描述（由申请人提供）：本申请的目标是为少数族裔申请人提供额外的培训，使她能够成为一名独立的RO1资助的研究者。该研究者完成了生理学生殖博士学位，这是发育生物学的博士后培训，目前是肺生物学部门的讲师。在执行本项目期间，主要研究者将获得以下方面的专业知识： 哺乳动物肺生物学、小鼠转基因技术、组织学和显微镜检查。儿科教授兼围产期研究所主任Jeff惠特塞特博士将担任主要研究者的导师。惠特塞特博士是国际公认的肺生物学领域的领导者。一个由杰出科学家组成的咨询委员会将就主要研究者的科学活动和职业发展提供咨询意见。该项目将在辛辛那提儿童医院医学中心的新生儿学和肺生物学部门进行，该部门致力于候选人的学术生涯，并为她作为独立研究者的发展提供理想的培训环境。该部门内的研究环境与整个医院的资源相结合，将最大限度地提高研究者在肺生物学领域建立科学利基的潜力。本申请的研究部分侧重于Wntless（一种致力于分泌Wnt配体的分子伴侣）控制气道形态发生的机制。在小鼠呼吸道中缺失Wntless导致气管和支气管软骨环缺失。Sox 9是软骨形成的主要调节因子，在平滑肌肌动蛋白的表达域扩展时未检测到。该提案将检验Wntless通过旁分泌机制调节软骨形成转录因子Sox 9诱导上气道模式化从而促进气管间充质分化的假设。具体目的是：1）确定Wntless在气管发育过程中的作用。该目的将鉴定由上皮产生并由Wntless分泌的Wnt配体。它也将定义这些配体介导的气管软骨形成的步骤。2)确定气管间充质细胞命运质量标准是否需要Wntless。使用细胞谱系追踪，我将研究体内气管间充质的细胞命运，我将在体外确定Wntless是否差异调节软骨形成和肌形成基因的表达。3)确定Wntless调控Sox9表达的机制。使用胚胎气管外植体培养，我将确定是否旁分泌典型或非典型信号控制的表达Sox 9在气管软骨。这些研究将提供关键的见解，了解很少的正常气管发育和气管软化症的病因。了解Sox转录因子如何通过Wnt信号传导来促进气管软骨发育，将为修复受损或畸形气道的新型细胞疗法奠定基础。 (End摘要）

DESCRIPTION (provided by applicant): The goal of this application is to provide the minority applicant with additional training that will enable her to become an independent RO1 funded investigator. This investigator completed her PhD in Reproduction of Physiology, a postdoctoral training in Developmental Biology and is currently an instructor in the Division of Pulmonary Biology. During the execution of this project, the principal investigator will acquire expertise in mammalian pulmonary biology, mouse transgenic technology, histology and microscopy. Dr. Jeff Whitsett, Professor of Pediatrics and Director of the Perinatal Institute, will serve as a mentor for the principal investigator. Dr. Whitsett is an internationally recognized leader in the field of Pulmonary Biology. An advisory committee comprise of outstanding scientists, will advise on scientific activities and career development of the principal investigator. This project will be carried out in the Division of Neonatology and Pulmonary Biology at Cincinnati Children's Hospital Medical Center, which is committed to the candidate's academic career and provides an ideal training setting for her development as an independent investigator. The research environment within the division combined with resources across the hospital will maximize the potential for the investigator to establish a scientific niche in pulmonary biology. The research component of this application focuses on the mechanisms by which Wntless, a chaperone dedicated to secretion of Wnt ligands, governs airway morphogenesis. Deletion of Wntless in mouse respiratory tract results in absent tracheal and bronchial cartilaginous rings. Sox9, a master regulator of chondrogenesis, is not detected while the expression domain of Smooth Muscle Actin is expanded. This proposal will test the hypothesis that Wntless induces upper airway patterning by modulation of chondrogenic transcription factor Sox9 via a paracrine mechanism thus promoting differentiation of tracheal mesenchyme. The specific aims are: 1) to define the role of Wntless during tracheal development. This aim will identify Wnt ligands produced by the epithelium and secreted by Wntless. It will also define steps in tracheal chondrogenesis mediated by these ligands. 2) To determine if Wntless is required for cell fate specification of the tracheal mesenchyme. Using cell lineage tracing I will study the cell fate of the tracheal mesenchyme in vivo and I will determine in vitro if Wntless differentially regulates expression of chondrogenic and myogenic genes. 3) To determine the mechanism by which Wntless regulates Sox9 expression. Using embryonic tracheal explant culture I will determine if paracrine canonical or non-canonical signaling controls the expression of Sox9 in tracheal cartilage. These studies will provide critical insights into the poorly understood normal tracheal development and the etiology of tracheomalacia. Understanding how Sox transcription factors are directed by Wnt signaling to promote tracheal cartilage development will lay the foundation for novel cell based therapies to repair damaged or malformed airways. (End of Abstract)