Role of the antiviral ribonuclease, RNase-L, in the host antibacterial response

抗病毒核糖核酸酶 RNase-L 在宿主抗菌反应中的作用

• 批准号: 7914406
• 负责人: BRET A HASSEL
• 金额: $ 37.5万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7914406
• 关键词: Affect; Anti-Bacterial Agents; Antibacterial Response; Antiviral Agents; Bacillus anthracis; Bacteria; Bacterial Infections; Biological; Biological Response Modifiers; Cathepsin E; Elements; Escherichia coli; Exhibits; Foundations; Gene Expression Regulation; Goals; Host Defense; Immune Response Genes; Immune response; Immune system; Immunity; Integration Host Factors; Interferons; Light; Mediating; Mediator of activation protein; Messenger RNA; Microarray Analysis; Molecular; Mus; Neutrophil Infiltration; Pathway interactions; Play; Predisposition; Process; Public Health; RNA Decay; Regulation; Ribonucleases; Role; Signal Pathway; Signal Transduction; Therapeutic; Therapeutic Agents; Trans-Activators; Transcript; Vacuole; Wild Type Mouse; antimicrobial; base; chemokine; combat; cytokine; immune function; mRNA Transcript Degradation; macrophage; mortality; novel; pathogen; public health relevance; response; therapeutic target; therapy development

DESCRIPTION (provided by applicant): Type 1 interferons (IFNs) were discovered as mediators of host antiviral functions, and were recently shown to play essential roles in the innate immune response to nonviral pathogens. Established effectors of IFN antiviral action may thus serve previously unrecognized roles in antibacterial immunity. To understand how IFN exerts its antibacterial activities, the identities and mechanisms of action of specific antibacterial effectors must be determined. Towards this goal, we identified a novel role for RNase-L, an IFN-regulated antiviral ribonuclease, in the host antibacterial response. RNase-L-/- mice exhibited a significant increase in mortality following bacterial challenge. The increased susceptibility of RNase-L-/- mice to bacterial challenge was due to a compromised immune response resulting in an increased bacterial load. Microarray analysis to identify RNase- L-regulated host transcripts that may mediate its antibacterial activity identified two classes of RNase-L- dependent gene regulation that affected transcripts encoding established immune mediators. Specifically, in RNase-L-/- macrophages: 1. basal expression of cathepsin-E (CatE), that mediates endolysosome-associated immune functions, was increased suggesting that this mRNA is an RNase-L substrate; and 2. bacteria-induced expression of proinflammatory cytokines and chemokines was diminished, suggesting that RNase-L indirectly impacts their expression via the modulation of upstream signaling pathway(s). Consistent with the altered CatE expression in RNase-L-/- macrophages, the endolysosome-mediated clearance of phagocytic vacuoles was disrupted following bacterial infection. Bacteria-induced signal transduction was impaired in RNase-L-/- macrophages, providing a mechanistic basis for the diminished cytokine and chemokine expression, and corresponding modulation of neutrophil recruitment. Based on these findings, we hypothesize that RNase-L exerts its antibacterial activity through multiple mechanisms including the regulation of CatE- mediated endolysosome functions, and the induction of host cytokines and chemokines. The goals of this proposal are to dissect the mechanisms by which RNase-L regulates the expression of host immune response genes (aims 1 and 2), and to determine the roles of this regulation in its antibacterial activity (aim 3). The antibacterial activity of RNase-L activators will also be examined. The proposed studies will provide the first information on the role of RNase-L in antibacterial activity, and will identify specific components of RNase-L action as targets for therapeutic modulation of the innate immune response. Public Health Relevance: Bacterial infections are a major public health problem, and the mechanisms by which the immune system combats bacterial infection are incompletely understood. The identification of key mediators of bacterial defense is essential for the development of therapies to enhance the antibacterial immune response. The proposed studies will provide the first information on the role of RNase-L as a novel mediator of antibacterial activity, and will evaluate the antibacterial activity of RNase-L activators as a new class of therapeutic agent.

描述（由申请人提供）：发现1型干扰素（IFN）是宿主抗病毒功能的介体，最近显示出在对非病毒病原体的先天免疫反应中起着重要作用。因此，IFN抗病毒作用的既定效应因素可能在抗菌免疫中起到以前未识别的作用。要了解IFN如何发挥其抗菌活性，必须确定特定抗菌效应子的作用的身份和机制。为了实现这一目标，我们确定了宿主抗菌反应中IFN调节的抗病毒核糖核酸酶RNase-L的新作用。 RNase-L - / - 小鼠在细菌挑战后的死亡率显着增加。 RNase-L - / - 小鼠对细菌挑战的敏感性增加是由于免疫反应受损导致细菌载荷增加所致。微阵列分析以识别可能介导其抗菌活性的RNase L调节的宿主转录本鉴定出两类的RNase-L-依赖基因调控，这些基因调节影响编码已建立的免疫介体的转录本。具体而言，在rNase-l - / - 巨噬细胞中：1。介导内溶血体相关的免疫功能的组织蛋白酶 - E（CATE）的基础表达增加，这表明该mRNA是RNase-L底物。和2。细菌诱导的促炎细胞因子和趋化因子的表达减少，这表明RNase-L间接影响其通过上游信号通路的调节（S）对其表达产生影响。与RNase-L - / - 巨噬细胞中的CATE表达变化一致，细菌感染后内溶液体介导的吞噬液泡的清除被破坏。细菌诱导的信号转导在RNase-L - / - 巨噬细胞中受损，为细胞因子和趋化因子表达降低的机械基础，以及中性粒细胞募集的相应调节。基于这些发现，我们假设RNase-L通过多种机制发挥其抗菌活性，包括调节CATE介导的内溶性函数，以及诱导宿主细胞因子和趋化因子和趋化因子。该提案的目标是剖析RNase-L调节宿主免疫反应基因表达的机制（目标1和2），并确定该调节在其抗菌活性中的作用（AIM 3）。还将检查RNase-L活化剂的抗菌活性。拟议的研究将提供有关RNase-L在抗菌活性中的作用的首次信息，并将识别RNase-L作用的特定组成部分作为对先天免疫反应的治疗调节的靶标。公共卫生相关性：细菌感染是一个主要的公共卫生问题，并且免疫系统与细菌感染作战的机制不完全理解。鉴定细菌防御的主要介质对于增强抗菌免疫反应的疗法的发展至关重要。拟议的研究将提供有关RNase-L作为抗菌活性的新介质作用的首次信息，并将评估RNase-L活化剂作为新的治疗剂的抗菌活性。