Immunosuppression by Myeloid Cells in Pneumonia - Project 3

肺炎中骨髓细胞的免疫抑制 - 项目 3

• 批准号: 10204082
• 负责人: Prabir Ray
• 金额: $ 42.78万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-03 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10204082
• 关键词: Acute Lung Injury; Adult Respiratory Distress Syndrome; Anti-Inflammatory Agents; Antibodies; Arylesterase; Bacteria; Bacterial Infections; Bacterial Pneumonia; Biochemical; Biological Assay; Cells; Chronic; Critical Illness; Cytokine Gene; Data; Enzymes; Exposure to; FRAP1 gene; Flow Cytometry; Frequencies; Gene Expression; Generations; Gluconolactonase; Goals; Hemorrhage; Human; Hydroxyeicosatetraenoic Acids; ITGAX gene; Immune; Immunoblotting; Immunological Models; Immunosuppression; Individual; Infection Control; Inflammation Mediators; Inflammatory; Interleukin-10; Interleukin-6; Investigation; Lactones; Lead; Ligands; Lipopolysaccharides; Lung; Lung infections; Magnetic Resonance Imaging; Mediator of activation protein; Messenger RNA; Metabolic; Modeling; Morbidity - disease rate; Mus; Myelogenous; Myeloid Cells; Myeloid-derived suppressor cells; Nuclear Receptors; Organ; Outcome; PPAR gamma; Patients; Peripheral; Peripheral Blood Mononuclear Cell; Phase; Phenotype; Plasma; Pneumonia; Population; Predisposition; Production; Prognosis; Pseudomonas; Pseudomonas aeruginosa; Reporting; Risk; Role; Sampling; Secondary to; Sepsis; Signal Transduction; T-Lymphocyte; TNF gene; Virulence Factors; adverse outcome; aryldialkylphosphatase; cell type; cytokine; genetic signature; homoserine lactone; imaging study; knock-down; lung injury; mTOR inhibition; macrophage; mouse model; novel; peripheral blood; quorum sensing; response; secondary infection; single-cell RNA sequencing

ABSTRACT A primary insult that precipitates sepsis can induce a profound state of immunosuppression, which renders an individual highly susceptible to secondary infections by bacteria such as Pseudomonas aeruginosa (PA). PA- induced pneumonia can cause acute respiratory distress syndrome (ARDS). We have established a 2-hit model in mice involving an initial peripheral exposure to bacterial lipopolysaccharide (LPS) followed by pulmonary infection with PA that induces immune suppression in the lung. The lungs of these mice show high levels of expression of the anti-inflammatory cytokine IL-10 but barely detectable expression of the pro- inflammatory cytokine IL-6. Compared to mice subjected to a single hit with PA only, those with 2-hits show increased morbidity, lung injury and lung bacterial dissemination. Pseudomonas secretes different virulence factors and the host in turn expresses enzymes called paraoxonases (PONs) to defend against these factors. PON2 was shown to induce a switch from pro-inflammatory M1 to suppressive M2 phenotype in macrophages (Mφs). We previously demonstrated increased numbers of regulatory myeloid cells resembling myeloid-derived suppressor cells (MDSCs) in the lung in response to LPS or bacterial infection that produce high levels of IL- 10. Studies of human sepsis have implicated peripheral blood MDSCs in chronic immune suppression and high plasma IL-10 levels were associated with poor prognosis in severely ill ARDS patients. Among cell types that defend against bacterial infections, a subset of innate-like T cells, MAIT cells, control infections of the lung by different bacteria including PA. We failed to detect MAIT cells in the peripheral blood of critically ill patients raising the possibility that susceptibility to secondary infections during sepsis is caused by a decline in host protective cells. Single cell RNA-seq (scRNA-seq) analysis of peripheral blood mononuclear cells (PBMCs) of patients show dynamic changes in gene expression, which may aid in prognosis. Collectively, these observations lead us to hypothesize that immune suppression in the lung during bacterial pneumonia involves dominance of anti-inflammatory mechanisms such as PPARγ and mTOR that induce increased generation of regulatory myeloid cells and increased expression of the anti-inflammatory mediators IL-10 and PON2 but decreased expression of host-protective mediators (IL-6, TNF-α) and cell types (MAIT cells). To prove this hypothesis, we will: Aim 1. Determine immune cell dynamics and gene signatures in PBMCs from critically ill patients and the role of mTOR in immune suppression. Aim 2. Determine the role of PPARγ and PON2 in persistent anti-inflammatory cytokine gene expression in the lungs of mice subjected to the 2-hit model.

摘要 导致脓毒症的原发性损伤可诱导严重的免疫抑制状态， 对细菌如铜绿假单胞菌（PA）的继发感染高度敏感的个体。PA- 诱发的肺炎可引起急性呼吸窘迫综合征（ARDS）。我们已经确定了两次袭击 小鼠模型，涉及初始外周暴露于细菌脂多糖（LPS），随后 PA肺部感染，导致肺部免疫抑制。这些小鼠的肺显示高 抗炎细胞因子IL-10的表达水平，但几乎检测不到促炎细胞因子IL-10的表达。 炎症细胞因子IL-6。与仅用PA进行单次撞击的小鼠相比，具有2次撞击的小鼠显示出 增加发病率、肺损伤和肺部细菌传播。假单胞菌分泌不同的毒力 宿主反过来表达称为对氧磷酶（脑桥）的酶来防御这些因子。 PON 2在巨噬细胞中诱导从促炎性M1表型到抑制性M2表型的转变 （Mφs）。我们先前证实了类似于髓源性的调节性髓样细胞数量增加， 肺中的抑制细胞（MDSC）响应LPS或细菌感染，产生高水平的IL-10， 10.人脓毒症的研究表明外周血MDSC参与慢性免疫抑制， 高血浆IL-10水平与严重ARDS患者预后不良相关。在细胞类型中 一种先天性类T细胞的亚群MAIT细胞控制肺部感染 包括PA在内的不同细菌。我们未能在危重患者的外周血中检测到MAIT细胞 提高了脓毒症期间继发感染的易感性是由宿主免疫力下降引起的可能性， 保护细胞图13：外周血单核细胞（PBMC）的单细胞RNA-seq（scRNA-seq）分析。 患者显示基因表达的动态变化，这可能有助于预后。总的来说，这些 观察结果使我们假设细菌性肺炎期间肺部的免疫抑制涉及 抗炎机制的优势，如PPARγ和mTOR，诱导增加的产生， 调节性骨髓细胞和抗炎介质IL-10和PON 2的表达增加， 宿主保护性介质（IL-6、TNF-α）和细胞类型（MAIT细胞）表达减少。 为了证明这个假设，我们将： 目标1.确定重症患者PBMC中的免疫细胞动力学和基因特征， mTOR在免疫抑制中的作用。 目标2.确定PPARγ和PON 2在持续性抗炎细胞因子基因中的作用 在经受2次打击模型的小鼠的肺中的表达。