Airway epithelial repair in chronic bronchitis: novel signaling mechanisms

描述（由申请人提供）：此提案描述了一个为期五年的培训计划，以发展细胞和发育生物学领域的学术生涯。首席研究员是一名受过全面临床训练的肺部/重症医学医生，在气道上皮细胞生物学方面接受了30个月的博士后培训。这个项目提供了一个独特的机会，在指导阶段获得额外的培训和技术，这将使我在这个奖项的前两年结束时能够独立。其余的目标将在独立阶段实现，使我更接近成为一名独立的内科科学家的长期目标。迈阿密大学的环境是独一无二的，可以让我探索我的假设，因为肺、重症监护和睡眠医学部门的气道生物学实验室在气道上皮细胞生物学方面有着悠久的成就记录。这个小组通过迈阿密大学生命联盟器官恢复小组获得了大量的人类气道上皮细胞，这使我能够继续他的研究。考虑到小组的地理位置很近，几个主要研究人员聚集在同一个研究空间，我在奖项指导阶段的训练将受益于许多经验丰富的研究人员，他们离我很近，并在日常基础上进行合作。我的职业规划将实验室经验与指导阶段的正式课程结合起来。这将允许我在独立阶段用目标中提出的额外工作来追求我的假设。本研究旨在进一步研究RA对Wnt信号传导的影响，并评估可能的治疗方案，以改善纤毛发生和预防鳞状化生。尽管这些通路对正常上皮细胞修复很重要，但在气道中的研究很少。最后一个目标也有很大的潜力发展成为一个翻译项目。慢性炎症性气道疾病，包括吸烟引起的慢性支气管炎，导致气道上皮损伤，随后导致纤毛黏液清除受损，这种情况与发病率和死亡率增加有关。另一方面，气道上皮在损伤后具有再生其规则结构的能力。在修复过程中，细胞增殖的初始阶段随后是上皮细胞的再分化。这一机制受发育信号机制如Wnt的再激活和视黄酸（RA）刺激的通路的调节。我的初步观察结果支持这样的假设，即RA剥夺和香烟烟雾暴露诱导的慢性支气管炎通过改变Wnt通路元件的表达导致鳞状皮化生（SM）和纤毛发生受损，这些结果可以通过激活PPAR3受体来改善。这一假设将通过研究构建来调查，以解决三个主要目标。目的1将确定特定的Wnt通路元件是否对纤毛发生和预防鳞状化生至关重要，RA是这一过程中不可或缺的调节因子（体外假设检验）。目的2将确定Wnt通路元件的表达是否在吸烟相关的慢性支气管炎患者中发生改变，以及这种改变是否导致SM和纤毛发育受损（患者样本的假设检验）。目的3将确定核受体（如PPAR3和维生素D）的激活是否可以阻止SM的发展，并通过替代RA（可能的治疗干预试验）来改善纤毛的发生。本研究计划解决了气道上皮如何正确修复的一个重要方面，而不是将其修复机制误导为可能导致发育不良和最坏情况下恶性肿瘤的鳞状化生。考虑到呼吸道疾病的持续增加，尤其是与吸烟有关的疾病，这项研究尤为重要。本研究旨在阐明气道上皮细胞修复的关键参数。

DESCRIPTION (provided by applicant): This proposal describes a five-year training program for the development of an academic career in the field of cell and developmental biology. The principal investigator is a fully clinically trained pulmonary / critical care medicine physician with 30 months postdoctoral training in airway epithelial cell biology. This program provides a unique opportunity to acquire additional training and techniques during the mentored phase of the award that will allow me to be independent at the end of the first two years of this award. The rest of the aims will then be pursued during the independent phase bringing me closer to my long- term goal of becoming an independent physician scientist. The environment at the University of Miami is uniquely qualified to allow me to explore my hypothesis as the Laboratories for Airway Biology in the Division of Pulmonary, Critical Care and Sleep Medicine have a long record of accomplishment in airway epithelial cell biology. This group has access to high number of human airway epithelial cells through the University of Miami Life Alliance Organ Recovery Group, which allows me to pursue his research. Given the close physical location of the group, with several principal investigators clustered in the same research space, my training during the mentored phase of the award will benefit from many experienced investigators that are close by and collaborate on a routine basis. My career plan combines laboratory experience with formal course work during the mentored phase. This will allow me to pursue my hypothesis with the additional work proposed in the aims during the independent phase. This research is to further examine the relevance of RA effects on Wnt signaling and evaluate possible therapeutic options to improve ciliogenesis and prevent squamous metaplasia. These pathways are poorly studied in the airway, despite their importance for proper epithelial cell repair. The last aim has also a strong potential to develop into a translational project. Chronic inflammatory airway diseases, including smoking-induced chronic bronchitis, lead to damage of the airway epithelium with subsequent impairment of mucociliary clearance, a condition associated with increased morbidity and mortality. On the other hand, the airway epithelium has the capacity to regenerate its regular structure after damage occurred. During repair, an initial phase of cell proliferation is followed by re-differentiation of epithelial cells. This mechanism is regulated by reactivation of developmental signaling mechanism such as Wnt and the pathways stimulated by retinoic acid (RA). My preliminary observations support the hypothesis that RA deprivation and cigarette smoke exposure- induced chronic bronchitis lead to squamous metaplasia (SM) and impaired ciliogenesis via altered expression of Wnt pathway elements and that these outcomes can be improved by activation of PPAR3 receptors. This hypothesis will be investigated through research constructed to address three major aims. 7 Aim 1 will determine whether specific Wnt pathway elements are essential for ciliogenesis and prevention of squamous metaplasia and that RA is an indispensable regulator of this process (test of hypothesis in vitro). 7 Aim 2 will determine whether the expression of Wnt pathway elements is altered in patients with smoking-related chronic bronchitis and whether this alteration leads to SM and impaired ciliogenesis (test of hypothesis with samples of patients). 7 Aim 3 will determine whether activation of nuclear receptors (e.g., PPAR3 and vitamin D) prevents the development of SM and improves ciliogenesis by substituting for RA (test of possible therapeutic intervention). This research proposal addresses an important aspect of how airway epithelia are properly repaired and not misdirect their repair mechanism into a squamous metaplasia that could lead to dysplasia and in the worst-case malignancy. This research is especially critical considering the continuing rise in airway diseases, especially related to smoking. The proposed research aims to elucidate critical parameters in airway epithelial cell repair. PUBLIC HEALTH RELEVANCE: This research proposal addresses an important aspect of how airway epithelia are properly repaired and not misdirect their repair mechanism into a squamous metaplasia that could lead to dysplasia and in the worst-case cancer. This research is especially critical considering the continuing rise in airway diseases, especially related to smoking. The proposed research aims to elucidate critical parameters in airway epithelial cell repair.