Mechanisms of Basal Cell Dysfunction in Chemical-induced Bronchiolitis Obliterans

项目总结 这项有指导的临床科学家研究职业发展申请将支持马修·麦格劳博士 作为一名研究呼吸道基底细胞功能障碍机制的临床科学家，他向独立的转变 在化学诱导闭塞性毛细支气管炎(BO)中。BO是一种毁灭性的纤维性呼吸道疾病，最常见的 在器官移植后看到的。然而，BO越来越频繁地与吸入接触到 某些病毒或化学物质。与吸入性BO有关的最广为人知的化学物质之一是 双乙酰(DA；2，3-丁二酮)，一种高活性的二酮，存在于食物、咖啡和电子烟中。尽管地方检察官 作为一种常用的调味剂，DA诱导BO的机制仍然知之甚少。中心到 BO的发生是对呼吸道上皮的损伤。当受损时，呼吸道依赖上皮祖细胞 以便进行适当的维修。这一应用的目的是为了更好地了解呼吸道基底细胞的功能作用， 人类呼吸道的原始祖细胞，在化学诱导的BO中。两种临床前药物模型- 诱导型BO就是为这一应用而开发的。首先，连续暴露在DA蒸气中的大鼠 持续性低氧血症，体重增加减少，以及BO的组织学证据。多泛素化蛋白质 在空气对照中未见的DA暴露后，在大鼠呼吸道中蓄积。第二，在人类呼吸道上皮细胞中 暴露在DA蒸气中，多泛素化蛋白积累并主要与气道基底部共定位 细胞。在重复暴露DA的情况下，多泛素化蛋白的积累导致了 呼吸道基底层细胞。我们的中心假设是重复暴露DA蒸气会导致大量的蛋白质损伤， 导致呼吸道基底层细胞蛋白毒性，损害呼吸道上皮修复，促进BO的发展。 这项提案的目的一将确定呼吸道基底细胞中丰富的蛋白质损伤如何损害上皮修复 并使用两种重复的DA蒸汽暴露模式促进BO的发展。AIM II将确定角色 泛素蛋白酶体系统在呼吸道基底细胞毒性和BO发生中的作用。AIM III将比较 多种泛素蛋白酶体途径药物靶点预防基底细胞毒性和BO的效果 发展。麦格劳博士组建了一个由呼吸道上皮生物学领域的专家组成的指导团队 (t Mariani，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)，用于关键检查呼吸道基底细胞在化学诱导的BO中所起的作用。呼吸道干细胞的指导 这项提案中描述的生物学和蛋白质组学将促进麦格劳博士向独立的过渡。在… K08完成后，此应用程序生成的数据将极大地促进我们对呼吸道的理解 吸入暴露后的基础细胞功能，并对邻近的研究领域产生更广泛的影响 吸入毒理学和BO的发展。

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.