CF sputum LC-MSMS - Proteomic profile of cystic fibrosis sputum cells in adults chronically infected with Pseudomonas aeruginosa

Lung disease is the main cause of morbidity and mortality in cystic fibrosis (CF), and involves chronic infection by a destructive microbiota and perturbed innate and adaptive immune responses. Tissue damage is considered to be mediated mostly by proteases, but other bacterial and host factors may also play a role. To determine the presence of potentially injurious proteins we employed semi-quantitative Multidimensional Protein Identification Technology to identify sputum cellular proteins with consistently altered expression in CF compared to healthy controls. Ingenuity Pathway Analysis, Gene Ontology functions, protein abundance and correlation with lung function were used to infer their clinical significance. The CF proteome exhibited differential expression of proteins relating to Rho family small GTPase activity, immune cell movement and activation, generation of reactive oxygen species and dysregulation of cell death and proliferation. Compositional breakdown established neutrophil extracellular trap proteins as the consistently most abundant cellular proteins detected, while a further 13 biologically relevant proteins were found to correlate negatively with lung function. These findings expand the current understanding of the mechanisms underlying CF lung disease and identify sputum cell proteins which might be useful as markers of disease status, prognostic indicators, stratification determinants for treatment prescription or as therapeutic targets.

肺部疾病是囊性纤维化（cystic fibrosis, CF）患者发病与死亡的首要诱因，其病理过程涉及破坏性微生物群介导的慢性感染，以及先天免疫与适应性免疫应答的紊乱。目前认为组织损伤主要由蛋白酶介导，但其他细菌与宿主因素或也发挥作用。为明确潜在损伤性蛋白的存在情况，本研究采用半定量多维蛋白质鉴定技术，对比分析囊性纤维化患者与健康对照者的痰液细胞蛋白质组，筛选出表达持续异常的蛋白。本研究通过Ingenuity通路分析（Ingenuity Pathway Analysis）、基因本体（Gene Ontology, GO）功能注释、蛋白质丰度分析，以及与肺功能的相关性分析，推断这些异常蛋白的临床意义。囊性纤维化患者的蛋白质组显示，与Rho家族小GTP酶活性、免疫细胞迁移与活化、活性氧（reactive oxygen species, ROS）生成，以及细胞死亡与增殖失调相关的蛋白均存在差异表达。蛋白质组组成分析显示，中性粒细胞胞外陷阱（neutrophil extracellular trap, NET）相关蛋白为本次检测到的丰度最高的持续存在的细胞蛋白；另有13种具有生物学相关性的蛋白与肺功能呈负相关。本研究结果拓展了当前对囊性纤维化肺部疾病潜在发病机制的认知，并筛选出可作为疾病状态标志物、预后指标、治疗方案分层依据，或潜在治疗靶点的痰液细胞蛋白。