Mechanisms of Basal Cell Dysfunction in Chemical-induced Bronchiolitis Obliterans

项目摘要 这个指导临床科学家研究职业发展应用程序将支持马修·麦格劳博士， 他作为一名临床科学家，研究气道基底细胞功能障碍的机制， 化学诱导的闭塞性细支气管炎（BO）。BO是一种破坏性的纤维化气道疾病，最常见于 在器官移植后看到的。然而，BO越来越频繁地与吸入暴露于 某些病毒或化学物质。与吸入诱导BO相关的最知名的化学物质之一是 二乙酰（DA; 2，3-丁二酮），一种在食品、咖啡和电子烟中发现的高活性二酮。尽管检察官 DA通常用作调味添加剂，但DA诱导BO的机制仍知之甚少。的核心 BO发展是对气道上皮的损伤。当受伤时，气道依赖于上皮祖细胞 进行适当的修复。本申请的目的是更好地理解气道基底细胞的功能作用， 在化学诱导的BO中，人气道的主要祖细胞。两种临床前化学模型- 为该应用开发了诱导BO。首先，连续暴露于DA蒸汽的大鼠 持续低氧血症、体重增加减少和BO的组织学证据。多泛素化蛋白 在空气对照中未观察到DA暴露后大鼠气道中的累积。第二，在人类气道上皮细胞中， 暴露于DA蒸气，多聚泛素化蛋白积聚并主要与气道基底膜共定位。 细胞随着DA的重复暴露，多聚泛素化蛋白的积累导致DA的蛋白毒性。 气道基底细胞我们的中心假设是重复的DA蒸汽暴露导致大量的蛋白质损伤， 导致气道基底细胞的蛋白毒性，损害气道上皮修复并促进BO发展。 本计划的目的是确定气道基底细胞中丰富的蛋白质损伤如何损害上皮修复 并使用两种重复DA蒸气暴露模型促进BO显影。目标二将决定作用 泛素蛋白酶体系统在气道基底细胞毒性和BO发展中的作用。目标三将比较 多种泛素蛋白酶体途径药物靶点在预防基底细胞毒性和BO中的功效 发展McGraw博士组建了一个由气道上皮生物学领域的专家组成的指导小组， （T马里亚尼，博士;初级）、吸入毒理学（JN Finkelstein，博士; I Rahman，博士）和蛋白质组学（WJ Qian， PhD）批判性地研究了气道基底细胞在化学诱导的BO中的作用。气道干细胞的指导 生物学和蛋白质组学，如本提案所述，将促进麦格劳博士向独立的过渡。在 K 08的完成，从这个应用程序产生的数据将显着推进我们对气道的理解 吸入暴露后的基底细胞功能，并对邻近的研究领域产生更广泛的影响， 吸入毒理学和BO开发。

PROJECT SUMMARY This Mentored Clinical Scientist Research Career Development application will support Dr. Matthew McGraw in his transition to independence as a clinician scientist studying the mechanisms of airway basal cell dysfunction in chemical-induced bronchiolitis obliterans (BO). BO is a devastating fibrotic airways disease, most commonly seen after organ transplant. However, BO is becoming more frequently associated with inhalation exposures to certain viruses or chemicals. One of the most well-known chemicals associated with inhalation-induced BO is diacetyl (DA; 2,3-butanedione), a highly reactive diketone found in foods, coffee and e-cigarettes. Despite DA’s common use as a flavoring additive, the mechanisms of DA-induced BO remain poorly understood. Central to BO development is injury to the airway epithelium. When injured, the airway relies on epithelial progenitor cells for proper repair. The objective of this application is to better understand the functional role of airway basal cells, the primary progenitor cell of the human airway, in chemical-induced BO. Two preclinical models of chemical- induced BO were developed for this application. First, rats exposed consecutively to DA vapors developed persistent hypoxemia, reduced weight gain, and histologic evidence of BO. Poly-ubiquitinated proteins accumulated in rat airways after DA exposures not seen in air controls. Second, in human airway epithelial cells exposed to DA vapors, poly-ubiquitinated proteins accumulated and co-localized primarily with airway basal cells. With repetitive DA exposures, the accumulation of polyubiquitinated proteins resulted in proteotoxicity of airway basal cells. Our central hypothesis is repetitive DA vapor exposures results in abundant protein damage, leading to proteotoxicity of airway basal cells, impairing airway epithelial repair and promoting BO development. Aim I of this proposal will determine how abundant protein damage in airway basal cells impairs epithelial repair and promotes BO development using both models of repetitive DA vapor exposure. Aim II will determine the role of the ubiquitin proteasome system in airway basal cell toxicity and BO development. Aim III will compare the efficacy of multiple ubiquitin proteasome pathway drug targets in preventing basal cell toxicity and BO development. Dr. McGraw has assembled a mentoring team of experts in the fields of airway epithelial biology (T Mariani, PhD; primary), inhalation toxicology (JN Finkelstein, PhD; I Rahman, PhD), and proteomics (WJ Qian, PhD) for critically examining the role of airway basal cells in chemical-induced BO. Mentoring in airway stem cell biology and proteomics, as described in this proposal, will facilitate Dr. McGraw’s transition to independence. At K08 completion, the data generated from this application will significantly advance our understanding of airway basal cell function following inhalation exposures and have a broader impact on neighboring research fields of inhalation toxicology and BO development.