Mechanisms of innate immune response modulation by mechanical ventilation

机械通气调节先天免疫反应的机制

• 批准号: 8212042
• 负责人: William A Altemeier
• 金额: $ 38.61万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8212042
• 关键词: Acute; Acute Lung Injury; Adult Respiratory Distress Syndrome; Agonist; Alveolar; Attenuated; Bacteremia; Binding; Biological Assay; Caring; Cell Wall; Cessation of life; Chronic; Critical Illness; DNA Binding; Data; Defect; Development; Distal; Dose; Environmental air flow; Epithelial Cells; Exposure to; Future; Gene Targeting; Generations; Genes; Genetic Transcription; Goals; Gram-Negative Bacteria; Hospitalization; Immune response; Incidence; Individual; Inflammation; Inflammatory Response; Interferons; Interleukin-1; Intervention; JNK-activating protein kinase; JUN gene; Knowledge; Lead; Length; Ligands; Link; Lipopolysaccharides; Lung; MAPK8 gene; Measures; Mechanical ventilation; Messenger RNA; Mitogen-Activated Protein Kinases; Modeling; Molecular; Mus; Myelogenous; Myeloid Cells; Nuclear Translocation; Pathogenesis; Pathway interactions; Patients; Pattern; Pattern Recognition; Phosphotransferases; Pneumonia; Principal Investigator; Promoter Regions; Protein Subunits; RNA Interference; Receptor Signaling; Recruitment Activity; Reporting; Research; Role; Safety; Secondary to; Severities; Signal Pathway; Signal Transduction; Source; Specificity; Testing; Tissue-Specific Gene Expression; Toll-Like Receptor 2; Toll-like receptors; Transcription Factor AP-1; Transgenic Mice; Ventilator; Ventilator-induced lung injury; activating transcription factor; adapter protein; base; cell type; chemokine; chromatin immunoprecipitation; design; disability; economic impact; human TLR3 protein; immunoregulation; improved; in vivo; injured; lung injury; microbial; mortality; mouse model; novel; pathogen; programs; promoter; public health relevance; research study; response; standard of care; toll-like receptor 4; transcription factor

DESCRIPTION (provided by applicant): Mechanical ventilation is frequently used to support critically ill patients even in the absence of overt lung injury. A recent study, however, has linked exposure to mechanical ventilation with subsequent development of the acute respiratory distress syndrome (ARDS). The mechanism linking mechanical ventilation with initiation of lung injury is unknown. We have shown that mechanical ventilation can alter the transcriptional response to low-dose bacterial product exposure leading to excessive inflammation and early development of lung injury. Our long-term goal is to identify how mechanical ventilation modulates the transcriptional response to microbial pathogens as a first step toward developing specific interventions to improve survival in mechanically ventilated patients. The specific hypothesis for this proposal is that mechanical ventilation activates the activator protein-1 (AP-1) transcription factor, which augments gene transcription in response to pathogen-associated molecular pattern (PAMP) recognition by toll-like receptors (TLRs). We base this hypothesis on the observations that: A) mechanical ventilation preferentially induces transcription of genes with a promoter region containing the AP-1 binding sequence, B) mechanical ventilation causes nuclear translocation of AP-1, C) mechanical ventilation synergistically augments mRNA levels of genes transcribed in response to lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria, and D) inhibition of c-Jun amino-terminal kinase (JNK - a kinase activator of AP-1) is protective against other types of lung injury. The specific aims of this proposal are to: 1) Determine whether ventilator augmentation of PAMP-induced inflammation is (a) specific for individual TLR- signaling pathways and/or (b) dependent on generation of endogenous TLR ligands. This aim is accomplished through the combination of highly specific toll-like receptor agonists and genetically modified mice, which lack either the MyD88 or TRIF adapter protein necessary for specific TLR signaling. 2) Determine the lung cell type primarily responsive to ventilator-induced immunomodulation by (a) measuring response to TLR ligands and ventilation in chimeric mice, which lack MyD88 in either myeloid or non- myeloid cells and (b) measuring response to TLR ligands and ventilation in transgenic mice in which distal lung epithelial cells have an isolated defect in downstream TLR signaling pathways. 3) Determine the role of AP-1 activation in ventilator-augmentation of LPS-induced inflammation by (a) using chromatin immunoprecipitation assay to identify which protein subunits of AP-1 are recruited to target gene promoters by mechanical ventilation, (b) inhibiting AP-1 activation during mechanical ventilation and LPS exposure, and (c) using RNA interference to determine the function of specific AP-1 subunits identified in (a). Relevance for public health - The incidence of acute lung injury (ALI) is 78.9 per 100,000 patient-years with a mortality rate of 38.5%. Based on these values, there are an estimated 190,600 cases of ALI in the U.S. each year with 74,500 associated deaths. Additionally, the economic impact of ALI is high secondary to prolonged ICU care and overall length of hospitalization and to chronic post-hospitalization disability. These data highlight the importance of further research to help understand the factors, which promote the development of ALI. This project will help identify mechanisms by which mechanical ventilation support causes lung injury; thereby, providing guidance for the development of future interventions to decrease the incidence and severity of acute lung injury.

描述（由申请人提供）：即使在没有明显的肺损伤的情况下，机械通气也经常用于支持重症患者。然而，最近的一项研究将接触机械通气与随后的急性呼吸窘迫综合征（ARDS）联系起来。将机械通气与肺损伤引发的机制尚不清楚。我们已经表明，机械通气可以改变对低剂量细菌产物暴露的转录反应，从而导致过度炎症和肺部损伤的早期发育。我们的长期目标是确定机械通气如何调节对微生物病原体的转录反应，这是开发特定干预措施以改善机械通气患者生存的第一步。该提议的特定假设是，机械通气激活了活化剂蛋白-1（AP-1）转录因子，该因子会增强基因转录，以响应与病原体相关的分子模式（PAMP）识别（TOLL样受体（TLR））。 We base this hypothesis on the observations that: A) mechanical ventilation preferentially induces transcription of genes with a promoter region containing the AP-1 binding sequence, B) mechanical ventilation causes nuclear translocation of AP-1, C) mechanical ventilation synergistically augments mRNA levels of genes transcribed in response to lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria, and d）抑制C-Jun氨基末端激酶（JNK- AP-1的激酶激活剂）可防止其他类型的肺损伤。该提案的具体目的是：1）确定PAMP诱导的炎症的呼吸机的增强是否（a）针对单个TLR信号通路的特异性和/或（b）取决于内源性TLR配体的产生。通过高度特定的Toll样受体激动剂和转基因小鼠的组合来实现此目标，这些小鼠缺乏特定TLR信号传导所需的MyD88或TRIF衔接蛋白。 2）确定（a）通过（a）测量对TLR配体的反应和通气的肺细胞类型，主要反应于呼吸机诱导的免疫调节，并在嵌合小鼠中缺乏MyD88，在髓样细胞或非髓样细胞中缺乏MyD88，以及（B）对TLR良好的小细胞的隔离和通风的响应，以隔离为单位的小细胞和通风。信号通路。 3）确定AP-1激活在LPS诱导的炎症中通过（a）使用染色质质免疫沉淀测定法确定AP-1的蛋白质亚基的作用（a）通过机械通风募集了哪些AP-1的蛋白质亚基来靶向基因启动子，（b）使用机械通风和LPS曝光过程中的AP-1激活（b）抑制AP-1的AP-1激活（C），并确定AP-1的aP-1均可用机械通风和LPS的功能（c）进行RRNNA的作用（C），（C） （a）。与公共卫生的相关性 - 急性肺损伤的发生率为每100,000名患者年78.9，死亡率为38.5％。基于这些值，美国估计有190,600例ALI病例，有74,500例相关死亡。此外，ALI的经济影响是长期护理和总体住院时间和慢性院后残疾的较高继发的。这些数据强调了进一步研究的重要性，以帮助了解促进ALI发展的因素。该项目将有助于确定机械通气支持导致肺损伤的机制；因此，为发展未来干预措施的发展提供指导，以减少急性肺损伤的发病率和严重程度。

项目成果

Experimental acute lung injury induces multi-organ epigenetic modifications in key angiogenic genes implicated in sepsis-associated endothelial dysfunction.

• DOI: 10.1186/s13054-015-0943-4
• 发表时间: 2015-05-11
• 期刊: Critical care (London, England)
• 作者: Bomsztyk K;Mar D;An D;Sharifian R;Mikula M;Gharib SA;Altemeier WA;Liles WC;Denisenko O
• 通讯作者: Denisenko O