Cigarette smoke and the acute respiratory distress syndrome: mechanisms and the role of alveolar macrophages in priming

项目摘要/摘要 急性呼吸窘迫综合征(ARDS)，也被称为急性肺损伤，是 发病率和死亡率，美国每年有近20万例，死亡率为30%-40%。香烟 吸烟最近被确定为患ARDS的一个危险因素。然而，很少有研究直接 研究了吸烟者易患ARDS的机制，包括肺泡的作用 巨噬细胞，肺泡腔中的主要细胞成分。此外，目前还不清楚 吸烟者只是容易患上ARDS，或者那些确实患有ARDS的人是否有 与患有ARDS的非吸烟者相比，损伤的关键通路的不同激活。进一步深入了解 在吸烟者和非吸烟者中，ARDS的机制都可以确定关键的预防和治疗 一种疾病的目标，没有有效的治疗方法。拟议的项目旨在研究这些机制。 通过这种机制，吸烟者会患上ARDS，并确定其发病机制 吸烟者和不吸烟者的ARDS有所不同。在目标1中，我将研究ARDS的发病机制 通过蛋白质生物标记物和转录组方法在已建立的危重患者队列中 确定与非吸烟者相比，吸烟者是否有不同的损伤激活途径。我假设 吸烟者会有不同激活的炎症、氧化应激和损伤途径 通过蛋白质生物标记物(假设1a)以及增加的促炎和氧化应激来衡量 BAL转录组中的基因表达(假设1b)。在目标2中，我将使用一个人体实验模型 应用吸入性脂多糖(LPS)治疗急性肺损伤探讨香烟 吸烟者已经做好了患ARDS的准备。我假设，在出现由内毒素模拟的“二次命中”时， 吸烟者的肺泡巨噬细胞会过度释放炎性细胞因子和 氧化剂/抗氧化剂失衡使吸烟者易患ARDS(假设2)。这些研究将 提供对吸烟者和非吸烟者ARDS生物学的更深入的了解，奠定了 为这些患者亚组的新预防和治疗策略奠定基础。要完成 为了实现这些目标，我组建了一个多学科的指导团队，他们的专业知识横跨相关领域 需要的学科包括1)卡罗琳·卡尔菲博士，她是我的主要导师和使用翻译的专家 研究急性呼吸窘迫综合征的人类队列技术迈克尔·马泰博士，他是我的合作导师，在使用方面有专业知识 研究ARDS发病机制的基础科学实验室方法3)科学顾问普雷斯科特·伍德拉夫博士 在a)基因组学，b)人类支气管镜研究和c)肺泡巨噬细胞和4) 丹尼尔·麦考利博士是一位科学顾问，在急性胰腺炎的人体模型中安全使用吸入性内毒素方面拥有专业知识 肺损伤。这种指导，以及旨在解决关键培训差距的培训计划，将使我能够 完成这份申请中提出的项目，并为我作为一名独立调查员的职业生涯做好准备。

PROJECT SUMMARY/ABSTRACT The acute respiratory distress syndrome (ARDS), also known as acute lung injury, is a major source of morbidity and mortality, with nearly 200,000 cases annually in the US and a mortality of 30-40%. Cigarette smoking has recently been identified as a risk factor for developing ARDS. However, few studies have directly examined the mechanisms that predispose smokers to develop ARDS, including the role of alveolar macrophages, the predominant cellular constituent in the alveolar space. Furthermore, it is unknown if cigarette smokers are simply predisposed to develop ARDS, or whether those that do develop ARDS have differential activation of key pathways of injury compared to non-smokers with ARDS. Further insight into the mechanisms of ARDS, both in smokers and non-smokers, may identify key preventative and therapeutic targets for a disease with no effective treatments. The proposed project aims to study the mechanisms through which cigarette smokers are primed to develop ARDS and to determine whether the pathogenesis of ARDS differs in cigarette smokers compared to non-smokers. In Aim 1, I will study the pathogenesis of ARDS via protein biomarker and transcriptomic approaches in an established cohort of critically ill patients to determine if smokers have differentially activated pathways of injury compared to non-smokers. I hypothesize that cigarette smokers will have differentially activated pathways of inflammation, oxidative stress and injury as measured by protein biomarkers (Hypothesis 1a) as well as increased pro-inflammatory and oxidative stress gene-expression in the BAL transcriptome (Hypothesis 1b). In Aim 2, I will use a human experimental model of acute lung injury using inhaled lipopolysaccharide (LPS) to investigate mechanisms through which cigarette smokers are primed to develop ARDS. I hypothesize that in the presence of a “second hit,” modeled by LPS, alveolar macrophages from cigarette smokers will have an exaggerated release of inflammatory cytokines and oxidant/antioxidant imbalance that predisposes smokers to develop ARDS (Hypothesis 2). These studies will provide increased insight into the biology of ARDS in both cigarette smokers and non-smokers, laying the foundation for novel preventative and therapeutic strategies in these subgroups of patients. To accomplish these aims, I have assembled a multidisciplinary mentoring team whose expertise spans the relevant disciplines needed including 1) Dr. Carolyn Calfee, my primary mentor and expert on using translational techniques in human cohorts to study ARDS 2) Dr. Michael Matthay, my co-mentor with expertise in using basic science laboratory approaches to study ARDS pathogenesis 3) Dr. Prescott Woodruff, a scientific advisor with expertise in a) genomics b) human bronchoscopy research studies and c) alveolar macrophages and 4) Dr. Daniel McAuley, a scientific advisor with expertise in safely using inhaled LPS in a human model of acute lung injury. This mentorship, along with a training plan designed to address key training gaps, will allow me to complete the projects proposed in this application and prepare me for a career as an independent investigator.