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

• 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
• 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

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.

项目总结/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， 了解在严重感染期间引起巨噬细胞功能障碍的因素仍然是一个高度优先事项， 生物医学研究巨噬细胞吞噬红细胞的急剧上升，称为应激 红细胞吞噬作用，发生在病理条件下，如输血血红素铁过载，贫血， 炎症、某些溶血性贫血或严重脓毒症，并涉及过量衰老红的摄取 细胞（sRBC）。使用红细胞输注和急性肺部感染的两次打击模型，我们最近发现 克雷伯氏菌感染后，应激性红细胞吞噬作用导致免疫抑制状态的机制 肺炎（KP）感染小鼠。这种免疫抑制状态是由干扰素干扰引起的。 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 STAT 1缺乏，这是干扰素反应的主要调节因子。我们之前建立了一个实验性的 巨噬细胞暴露于KP感染和伴随的sRBC递送或过量氯化血红素的系统， 体外此外，我们已经使用KP开发了一个完善的细菌性肺炎模型系统， 结合直接递送sRBC或血红素至肺以检查巨噬细胞中的改变， 表型和体内免疫细胞库。这项提议将检验这一假设，即过量的血红素在 肺，例如在严重感染期间局部组织损伤的情况下，可诱导STAT 1缺陷的状态 在巨噬细胞中，部分是通过损害STAT 1蛋白的稳定性，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：目标1。确定在KP过程中过量血红素是否诱导巨噬细胞中STAT 1缺乏的状态 通过损害体外STAT 1蛋白稳定性感染。目标二。检查过量血红素是否改变巨噬细胞 表型在肺中，并在体内KP感染期间损害有效的宿主防御。成功完成 该项目将提供关于在病理条件下宿主-病原体相互作用的新信息， 过量的血红素，并将解决在严重的肺疾病中对宿主反应失调的理解上的差距。 呼吸道感染