Bronchoalveolar Lavage Cell Biomarkers in Lung Rejection

描述（由申请人提供）：肺移植已在超过20，000例晚期肺病患者中进行，两年生存率为70%，生活质量显著改善。然而，长期存活率仍然低于肾，心脏和肝脏受体，主要是由于急性和慢性肺排斥反应（闭塞性细支气管炎综合征，BOS）的影响。目前预测和诊断肺排斥反应的方法是不精确和侵入性的，并且不允许在肺功能不可逆丧失之前诊断慢性排斥反应。同种异体肺非常适合通过支气管肺泡灌洗（BAL）进行研究，这允许对支气管肺泡微环境进行相对非侵入性的采样。因此，我们的目标是利用BAL细胞中的基因表达来改善肺排斥反应的预测、诊断和治疗。我们先前的研究表明，急性肺排斥组织学的特征是细胞毒性T淋巴细胞标志物的BAL细胞表达协同增加;并且BAL液和细胞揭示了慢性肺排斥中标志性病理生理过程的生物标志物。为了扩展这些发现，我们提出了两个假设，每个假设都有一个相关的具体目标。假设1：支气管肺泡灌洗（BAL）细胞基因表达的特定模式发生在急性排斥反应，因此可以作为诊断生物标志物。在具体目标1中，我们将通过以下方式完善和验证我们的急性肺排斥诊断模型：a）调整对常见支气管定植微生物基因表达的影响;和B）在肺受体的纵向前瞻性研究中验证最终急性肺排斥诊断模型。特异性目的1的成功完成将为使用BAL作为主要急性排斥诊断工具铺平道路，为有问题的病例保留更多的侵入性肺活检。假设二：BOS发病机制中涉及的特定生物学机制-包括先天性和适应性免疫的激活;中性粒细胞/趋化因子介导的炎症通路的激活;异常上皮细胞信号传导;和气道纤维化-反映在BAL细胞基因表达中。在特定目标2中，我们将通过以下方式定义反映闭塞性细支气管炎综合征发病机制中涉及的特定生物学机制的基因模块的BAL细胞表达：a）评价BOS发作时已知机制基因模块的表达;和B）鉴定可作为BOS候选生物标志物的新基因和途径。具体目标2的成功完成将为开发基于机制的BOS诊断和预测测试提供经验基础。这些发现将立即使用，并将改善肺移植受者的临床管理。基于我们在肺移植中以患者为导向的蛋白质组学和基因组学研究的历史，我们具有独特的优势来开展拟议的研究;我们强大的调查团队;以及我们出色的基因组研究环境。公共卫生相关性：肺移植已在超过20，000例晚期肺病患者中进行，两年生存率约为70%，生活质量显著改善。然而，长期存活率大大低于肾，心脏和肝脏受体，主要是由于急性和慢性肺排斥反应的影响。我们的总体研究目标是减少肺移植后排斥反应的负面影响。在拟议的研究中，我们将研究肺细胞中的基因表达，以开发在对移植肺造成不可逆损伤之前识别肺排斥反应的新方法。

DESCRIPTION (provided by applicant): Lung transplants have been performed in over 20,000 individuals with advanced lung disease, with two-year survival of 70% and dramatic improvements in quality of life. However, long-term survival rates remain lower than those of kidney, heart, and liver recipients, largely due to the effects of acute and chronic lung rejection (bronchiolitis obliterans syndrome, BOS). Current methods of predicting and diagnosing lung rejection are imprecise and invasive, and do not allow diagnosis of chronic rejection prior to irreversible loss of lung function. The lung allograft is ideally suited to study by bronchoalveolar lavage (BAL), which allows relatively non-invasive sampling of the bronchoalveolar microenvironment. Therefore, our objective is to use gene expression in BAL cells to improve prediction, diagnosis, and treatment of lung rejection. Our prior studies demonstrate that acute lung rejection histology is characterized by coordinately increased BAL cell expression of cytotoxic T-lymphocyte markers; and that BAL fluid and cells reveal biomarkers of the hallmark patholophysiologic processes in chronic lung rejection. To expand upon these findings we propose two hypotheses, each with a related Specific Aim. Hypothesis 1: Specific patterns of bronchoalveolar lavage (BAL) cell gene expression occur during acute rejection, and therefore can serve as diagnostic biomarkers. In Specific Aim 1, we will refine and validate our acute lung rejection diagnostic model by: a) adjusting for the effects on gene expression of common bronchial colonizing organisms; and b) validating the final acute lung rejection diagnostic model in a longitudinal, prospective study of lung recipients. Successful completion of Specific Aim 1 will pave the way to use BAL as the primary acute rejection diagnostic tool, reserving more invasive lung biopsies for problematic cases. Hypothesis 2: Specific biological mechanisms involved in BOS pathogenesis--including activation of innate and adaptive immunity; activation of neutrophil/chemokine-mediated inflammatory pathways; abnormal epithelial cell signaling; and airway fibrosis-are reflected in BAL cell gene expression. In Specific Aim 2, we will define the BAL cell expression of gene modules that reflect specific biological mechanisms involved in bronchiolitis obliterans syndrome pathogenesis by: a) evaluating the expression of known mechanism-based gene modules at the time of BOS onset; and b) identifying novel genes and pathways that can serve as candidate biomarkers for BOS. Successful completion of Specific Aim 2 will provide an empirical basis for development of mechanism-based diagnostic and predictive tests for BOS. These findings will be of immediate use, and will improve the clinical management of lung transplant recipients. We are uniquely positioned to carry out the proposed research based on our history of patient-oriented, proteomic, and genomic research in lung transplantation; our strong investigative team; and our outstanding genomic research environment. PUBLIC HEALTH RELEVANCE: Lung transplants have been performed in over 20,000 individuals with advanced lung disease, with two-year survival of approximately 70% and dramatic improvements in quality of life. However, long-term survival rates are considerably lower than those enjoyed by kidney, heart, and liver recipients, largely due to the effects of acute and chronic lung rejection. Our overall research goal is to reduce the negative impact of rejection after lung transplantation. In the proposed studies, we will study gene expression in lung cells in order to develop new ways of identifying lung rejection before it results in irreversible damage to the transplanted lungs.