Genes Mediating Innate Immune Suppression by Hypercapnia in Mammals and Flies

哺乳动物和果蝇高碳酸血症介导先天免疫抑制的基因

基本信息

批准号：
8238710
负责人：
GREG J BEITEL
金额：
$ 37.02万
依托单位：
NORTHWESTERN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-12-15 至 2015-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8238710
关键词：
Acute Adult Adverse effects Bacterial Infections Binding Blood CCL2 gene Candidate Disease Gene Carbon Dioxide Cause of Death Cells ChIP-seq Chromatin Chronic Chronic Obstructive Airway Disease Clinical Communities Complex Data Defect Drosophila genus Foundations Future Gene Components Gene Expression Gene Targeting Genes Genetic Transcription Histones Homologous Gene Host Defense Human Hypercapnia Immune Immune Response Genes Immunosuppression Immunosuppressive Agents In Vitro Individual Infection Inflammatory Interleukin-6 Lung Lung diseases Mammals Mediating Mediator of activation protein Molecular Mus Mutation Natural Immunity Orthologous Gene Outcome Pathway interactions Patients Phagocytes Play Pneumonia Predisposition Proteins Pseudomonas aeruginosa RNA Interference Regulator Genes Risk Risk Factors Role System TNFRSF5 gene Testing Time Tissues Validation Zinc Fingers antimicrobial peptide bacterial resistance base fly genome-wide histone methyltransferase homeodomain in vivo macrophage mortality mouse model p65 prevent promoter response transcription factor

项目摘要

DESCRIPTION (provided by applicant): Hypercapnia, elevation of PCO2 in blood and tissue, commonly occurs in severe acute and chronic lung disorders, such as chronic obstructive pulmonary disease (COPD). Patients with advanced COPD frequently develop bacterial lung infections, and hypercapnia is a risk factor for mortality in such individuals, as in those with community-acquired pneumonia. We have shown that hypercapnia suppresses transcription of innate immune response genes required for host defense in human, mouse and Drosophila cells, and increases mortality due to bacterial infections in mice and Drosophila. These findings suggest that hypercapnia is not simply a marker of advanced lung disease, but plays a causal role in poor clinical outcomes by increasing susceptibility to infection. Our data also strongly suggest that hypercapnia inhibits innate immunity and host defense by pathway(s) conserved from Drosophila to mammals. Because the molecular mediator(s) of hypercapnic immune suppression are undefined, we conducted a genome-wide RNAi screen in cultured Drosophila cells, which identified ~140 genes required for hypercapnic suppression of antimicrobial peptide (AMP) genes. The 5 most potent of these candidate CO2-mediators encode the zinc finger homeodomain transcription factor, Zfh2; a histone deactylase; a histone methyltransferase; a chromatin-associated Ig-repeat protein; and a Rac-interacting protein. None of these genes were previously known to have immunoregulatory function. Exciting new data indicate that mutations in zfh2 protect adult Drosophila against CO2-induced host defense defects. Thus, we hypothesize that Zfh2 and the proteins encoded by the other 4 candidate genes are components of pathway(s) by which hypercapnia suppresses innate immune gene expression and host defense in Drosophila, and that the mammalian orthologs of these genes mediate hypercapnic suppression of innate immune/host defense genes in mouse and human phagocytes. In the case of Zfh2 and its mammalian orthologs, ZFHX3 and ZFHX4, we further hypothesize that hypercapnia alters their abilities to bind target gene promoters or components of the NF-:B transcriptional complex, or modifies the transcriptional activity of these factors, thereby decreasing expression of specific innate immune/host defense genes. In the proposed studies, we will test these hypotheses in vitro using cultured fly, mouse and human macrophages, and in vivo using adult Drosophila and lung inflammatory cells obtained from mice with Pseudomonas aeruginosa pneumonia. These studies will for the first time define components of conserved pathway(s) by which hypercapnia impairs innate immunity and host defense, and determine their mechanisms of action. The results should lay the basis for future studies aimed at preventing hypercapnic immune suppression in patients with advanced lung disease. PUBLIC HEALTH RELEVANCE: Hypercapnia, or elevation of the level of carbon dioxide (CO2) in the body, commonly develops in people with advanced lung diseases. These individuals more frequently develop lung infections and have an increased risk of dying. This project will determine how hypercapnia leads to more and worse infections by determining the function of the first identified mediator of hypercapnic immune suppression, and by identifying additional components of immunosuppressive CO2-response pathways .

描述（由申请人提供）：高碳酸盐，血液和组织中PCO2的升高，通常发生在严重的急性和慢性肺部疾病中，例如慢性阻塞性肺疾病（COPD）。患有晚期COPD的患者经常出现细菌性肺部感染，而高碳酸血症是此类患者死亡率的危险因素，例如患有社区获得性肺炎的人。我们已经表明，高碳酸酯抑制了人，小鼠和果蝇细胞中宿主防御所需的先天免疫反应基因的转录，并因小鼠和果蝇中细菌感染而增加死亡率。这些发现表明，高碳酸血症不仅是晚期肺部疾病的标志，而且还通过增加感染易感性而在不良的临床结局中起因果作用。我们的数据还强烈表明，高碳酸盐抑制了从果蝇到哺乳动物保守的途径抑制先天免疫和宿主防御。由于超碳免疫抑制的分子介体（S）是不确定的，因此我们在培养的果蝇细胞中进行了全基因组RNAi筛选，该细胞鉴定出〜140个基因抑制过度抑制抗菌肽（AMP）基因所需的基因。这些候选二氧化碳中最有效的二氧化碳媒介物中最有效的锌指同源域转录因子ZFH2；组蛋白脱纤酶；组蛋白甲基转移酶；与染色质相关的Ig重复蛋白；和赛车蛋白。这些基因以前均不具有免疫调节功能。令人兴奋的新数据表明，ZFH2突变保护成年果蝇免受二氧化碳诱导的宿主防御缺陷。因此，我们假设其他四个候选基因编码的ZFH2和蛋白质是途径的组成部分，通过该途径，高capnia抑制了果蝇中的先天免疫基因的表达和宿主防御，并且这些基因的哺乳动物矫正力介导了这些基因的哺乳动物矫形，介导了对生物抗拒的捍卫者和人类的过度抑制小鼠和人类的pen剂和人类的pen夫。 In the case of Zfh2 and its mammalian orthologs, ZFHX3 and ZFHX4, we further hypothesize that hypercapnia alters their abilities to bind target gene promoters or components of the NF-:B transcriptional complex, or modifies the transcriptional activity of these factors, thereby decreasing expression of specific innate immune/host defense genes.在拟议的研究中，我们将使用培养的苍蝇，小鼠和人类巨噬细胞在体外测试这些假设，并使用成年果蝇和肺炎性细胞在体内进行体内测试。这些研究将首次定义保守途径的组成部分，通过该途径，高碳酸盐会损害先天的免疫力和宿主防御，并确定其作用机理。结果应为未来的研究奠定旨在防止晚期肺部疾病患者过度抑制过度抑制免疫抑制的基础。公共卫生相关性：体内二氧化碳（CO2）水平的高碳酸盐症通常在患有晚期肺部疾病的患者中发展。这些人更频繁地发展为肺部感染，并且死亡风险增加。该项目将通过确定第一个鉴定出的高碳免疫抑制介质的功能以及鉴定免疫抑制性CO2反应途径的其他成分，来确定高碳酸脂蛋白如何导致更多和更糟的感染。