Cardiac microlesion formation during invasive pneumococcal disease

侵袭性肺炎球菌疾病期间心脏微病变的形成

• 批准号: 10517516
• 负责人: Carlos J Orihuela
• 金额: $ 44.48万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10517516
• 关键词: Acetates; Adult; Adverse event; Antibodies; Antioxidants; Area; Arrhythmia; Attenuated; Autopsy; Bacteremia; Blood; Blood Circulation; Carbon; Cardiac; Cardiac Electrophysiologic Techniques; Cardiac Myocytes; Cardiotoxicity; Cell Death; Cell membrane; Cells; Cessation of life; Disease; Drops; Enzymes; Event; Formates; Gene Expression; Genes; Glucose; Glucose-6-Phosphate; Goals; Gram-Positive Bacteria; Gram-Positive Cocci; Heart; Heart Injuries; Heart failure; Hospitalization; Human; Hydrogen Peroxide; In Vitro; Individual; Inflammatory; Invaded; Ions; Learning; Lesion; Link; Metabolic; Metabolism; Microbial Biofilms; Mus; Mutation; Myocardial; Myocardial Infarction; Myocardium; Passive Immunization; Pathogenesis; Pneumococcal Infections; Pneumonia; Process; Production; Pyruvate; Pyruvate Metabolism Pathway; Pyruvate Oxidase; Research; Risk Factors; Role; Sampling; Seminal; Streptococcus; Streptococcus pneumoniae; Streptococcus pneumoniae plY protein; Testing; Therapeutic Intervention; Toxin; Virulence; Work; acetyl phosphate; cell killing; clinical epidemiology; community acquired pneumonia; cytotoxic; epidemiology study; experience; experimental study; heart damage; in vivo; mortality; mutant; nonhuman primate; oxidative damage; programs; prototype; targeted treatment; tempol; transcriptome sequencing; uptake

ABSTRACT: One-in-four adults hospitalized for community-acquired pneumonia (CAP) experience an adverse cardiac event. Clinical epidemiological studies, as well as those performed in mice, non-human primates, and with human autopsy samples indicate that Streptococcus pneumoniae (Spn), the leading cause of CAP, can invade the heart from the bloodstream and cause direct cardiotoxicity. Within the myocardium Spn cause focal areas of damage we have called microlesions and these disrupt contractility. One recent break-through in our understanding of Spn pathogenesis was the observation that pneumococci are taken up by cardiomyocytes and Spn kill these cells from within. What is more, the pore-forming toxin pneumolysin and Streptococcal pyruvate oxidase (SpxB) derived H2O2 were both requisite for cardiotoxicity. Herein, our goal is to gain an understanding of the events that take place within a cardiomyocyte immediately after Spn uptake. Along such lines, results from in vitro and in vivo experiments, including dual-species RNA sequencing of Spn- infected hearts, have revealed highly compelling connections between changes in carbon availability, H2O2 production, biofilm / cardiac microlesion formation, and pneumolysin production. Thus, we hypothesize that glucose restriction encountered by Spn within a cardiomyocyte, and again in cardiac microlesions, results in metabolic and gene expression changes that enhance bacterial cardiotoxicity. To test this hypothesis and learn how pneumolysin and H2O2 work together to kill cardiomyocytes we will: AIM 1: Determine how environmental glucose, metabolism, and virulence are interlinked. To elucidate the basis, extent, and consequences of these connections we will: 1) determine how purposeful shunting of pyruvate metabolism (by means of mutation) towards the production of acetate, lactate, and/or formate impacts gene expression under high and low glucose conditions; 2) identify how Spn gene expression changes in longitudinal fashion after bacterial uptake by a cardiomyocyte and how this is linked to changes in Spn metabolism; 3) determine the importance of metabolism-linked genes to Spn survival within a cardiomyocyte, killing of the cardiomyocyte, and the overall disease process. AIM 2: Determine how bacterial derived H2O2, together with pneumolysin, kills cardiomyocytes. SpxB derived H2O2 and pneumolysin are both required for Spn killing of cardiomyocytes; each alone is insufficient. To determine why we will: 1) determine how varying production of H2O2 and pneumolysin together modulate the form of cardiomyocyte death; 2) determine if H2O2 potentiates pneumolysin production, its release from Spn, or host cell membrane targeting; and, 3) determine if SpxB-derived H2O2 contributes to the ion dysregulation that has previously been implicated in pneumolysin-induced necroptosis. This aim, at its completion, will advance our understanding of how Spn kills host cells.

抽象的： 四分之一的成年人住院的社区获得性肺炎（CAP）经历不良心脏 事件。临床流行病学研究以及在小鼠，非人类灵长类动物以及与 人体尸检样品表明肺炎链球菌（SPN）是CAP的主要原因，可以入侵 血液中的心脏并引起直接心脏毒性。在心肌内，SPN导致焦点区域 我们称之为造成的损坏，这些破坏了收缩力。我们最近的一次突破 对SPN发病机理的理解是，肺炎球菌被心肌细胞吸收 SPN从内部杀死这些细胞。更重要的是，孔形成孔毒素肺炎和链球菌 衍生出H2O2的丙酮酸氧化酶（SPXB）都是心脏毒性的必要条件。在这里，我们的目标是获得 了解SPN吸收后立即在心肌细胞中发生的事件。 沿着这样的线，体外和体内实验的结果，包括SPN-的双物种RNA测序 感染的心脏揭示了碳供应变化之间的高度令人信服的联系，H2O2 生产，生物膜 /心脏微观形成和肺炎生产。因此，我们假设 SPN在心肌细胞中遇到的葡萄糖限制，并在心脏微观中再次导致 代谢和基因表达变化，增强了细菌心脏毒性。检验这一假设并学习 肺炎和H2O2如何共同杀死心肌细胞： 目标1：确定环境葡萄糖，代谢和毒力如何相互联系。阐明 这些联系的基础，程度和后果我们将：1）确定如何有目的的分类 丙酮酸代谢（通过突变）朝着乙酸，乳酸和/或甲酸甲酸盐的影响产生 在高葡萄糖条件下的基因表达； 2）确定SPN基因表达如何变化 心肌细胞细菌摄取后的纵向方式，以及如何与SPN的变化有关 代谢; 3）确定与代谢基因在心肌细胞内生存的重要性， 杀死心肌细胞和整体疾病过程。 AIM 2：确定细菌衍生的H2O2与肺炎素如何杀死心肌细胞。 SPXB SPN杀死心肌细胞需要衍生的H2O2和肺炎素。每个人都不足够。 确定我们为什么要：1）确定H2O2和肺炎的产生如何调节 心肌细胞死亡的形式； 2）确定H2O2是否增强了肺炎的产生，其释放从 SPN或宿主细胞膜靶向； 3）确定SPXB衍生的H2O2是否有助于离子 以前与肺炎诱导的坏死作用有关的失调。这个目标， 完成，将促进我们对SPN如何杀死宿主细胞的理解。