Heme-mediated STAT1 Dysfunction in Macrophages During Klebsiella pneumoniae Lung Infection

肺炎克雷伯菌肺部感染期间巨噬细胞中血红素介导的 STAT1 功能障碍

基本信息

批准号：
10534918
负责人：
Shekina Gonzalez-Ferrer
金额：
$ 4.68万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-05 至 2025-08-04
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10534918
关键词：
Acute Acute Respiratory Distress Syndrome Address Anemia due to Chronic Disorder Antioxidants Autophagocytosis Bacteremia Bacterial Infections Bacterial Pneumonia Biochemical Genetics Biological Models Biological Process Biomedical Research Blood Transfusion Bone Marrow Cells Development Dysmyelopoietic Syndromes Effector Cell Erythrocytes Erythrophagocytosis Excision Exhibits Exposure to Functional disorder Gene Expression Profile Healthcare Hematological Disease Heme Heme Iron Hemeproteins Hemin Hemoglobin Hemolytic Anemia Hemorrhage Host Defense IRF1 gene Immune Immune response Immunosuppression Impairment In Vitro Infection Inflammation Inflammatory Injury Interferons Invaded Iron Iron Overload Kidney Kinetics Klebsiella pneumoniae Leukocyte Elastase Life Liver Lung Lung infections Macrophage Activation Mediating Metabolism Modeling Mus Oxidative Stress Pathogenesis Pathogenicity Pathologic Patients Phenotype Physiological Prevention strategy Process Production Proteins Recycling Respiratory Tract Infections Risk STAT1 protein Sepsis Sickle Cell Anemia Signal Transduction Stress Structure System Testing Tissues Transfusion Wild Type Mouse antimicrobial peptide base chemokine combat confocal imaging cytokine genetic approach high risk in vivo in vivo Model macrophage mortality neutrophil novel opportunistic pathogen pathogen protein expression resilience response senescence transcription factor treatment strategy uptake

项目摘要

PROJECT SUMMARY/ABSTRACT Macrophages are key effector immune cells in host defense against pathogen invasion, and understanding factors that cause macrophage dysfunction during severe infection remains a high priority in biomedical research. An acute rise in red blood cell engulfment by macrophages, called stressed erythrophagocytosis, occurs in pathologic conditions such as transfusion heme-iron overload, anemia of inflammation, certain hemolytic anemias, or severe sepsis, and involves the uptake of excess senescent red cells (sRBCs). Using a two-hit model of red cell transfusion and acute pulmonary infection, we recently uncovered a mechanism whereby stressed erythrophagocytosis led to a state of immunosuppression following Klebsiella pneumoniae (KP) infection in mice. This state of immunosuppression arose from a disruption in interferon signaling in the liver during infection, was caused by excess heme handling by macrophages, and led to a deficiency of STAT1, a master regulator of interferon responses. We previously established an experimental system in which macrophages are exposed to KP infection and concomitant sRBC delivery or excess hemin in vitro. In addition, we have developed a well-established bacterial pneumonia model system using KP that will be combined with direct delivery of sRBC or heme to the lung in order to examine alterations in macrophage phenotype and the immune cell repertoire in vivo. This proposal will test the hypothesis that excess heme in the lung, such as in conditions of local tissue damage during severe infection, can induce a state of STAT1-deficiency in macrophages, in part, by impairing STAT1 protein stability with deleterious consequences on host defense. Utilizing in vitro and in vivo model systems, I propose to investigate this hypothesis by pursuing the following aims: Aim 1. Determine whether excess heme induces a state of STAT1 deficiency in macrophages during KP infection by impairing STAT1 protein stability in vitro. Aim 2. Examine whether excess heme alters macrophage phenotype in the lung and impairs effective host defense during KP infection in vivo. Successful completion of this project will provide novel information regarding host-pathogen interactions during pathologic conditions of excess heme, and will address a gap in understanding of dysregulated host response in the lung during severe respiratory infection.

项目概要/摘要巨噬细胞是宿主防御病原体入侵的关键效应免疫细胞，了解严重感染期间导致巨噬细胞功能障碍的因素仍然是重中之重生物医学研究。巨噬细胞吞噬红细胞的急剧增加，称为应激噬红细胞作用，发生在病理情况下，例如输血血红素铁超载、贫血炎症、某些溶血性贫血或严重败血症，并涉及吸收过量的衰老红细胞（sRBC）。使用红细胞输注和急性肺部感染的二次打击模型，我们最近发现克雷伯菌感染后应激性噬红细胞作用导致免疫抑制状态的机制小鼠肺炎支原体（KP）感染。这种免疫抑制状态是由干扰素破坏引起的感染期间肝脏中的信号传导是由巨噬细胞处理过量血红素引起的，并导致 STAT1 缺乏，STAT1 是干扰素反应的主要调节因子。我们之前建立了一个实验巨噬细胞暴露于 KP 感染和伴随的 sRBC 输送或过量血红素的系统体外。此外，我们还利用 KP 开发了一个完善的细菌性肺炎模型系统，该系统将用于与直接将 sRBC 或血红素输送至肺部相结合，以检查巨噬细胞的变化表型和体内免疫细胞库。该提案将检验以下假设：肺部，例如在严重感染期间局部组织损伤的情况下，可以诱发 STAT1 缺陷状态在巨噬细胞中，部分是通过损害 STAT1 蛋白稳定性来对宿主防御产生有害后果。利用体外和体内模型系统，我建议通过以下方式研究这一假设目标：目的 1. 确定过量血红素是否会在 KP 期间诱导巨噬细胞出现 STAT1 缺陷状态通过损害 STAT1 蛋白体外稳定性来抑制感染。目标 2. 检查过量的血红素是否会改变巨噬细胞体内 KP 感染期间，肺部表型会损害宿主的有效防御。顺利完成该项目将提供有关病理条件下宿主与病原体相互作用的新信息过量的血红素，并将解决严重期间肺部宿主反应失调的理解空白呼吸道感染。