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

基本信息

批准号：
9891766
负责人：
Carlos J Orihuela
金额：
$ 45.55万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
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/9891766
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 Clinical Communities Disease Drops Enzymes Event Gene Expression Genes Glucose Glucose-6-Phosphate Goals Gram-Positive Bacteria Gram-Positive Cocci Heart Heart Injuries Heart failure Human Hydrogen Peroxide In Vitro Individual Inflammatory Invaded Ions Learning 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 Time Toxin Virulence Work acetyl phosphate cell killing cytotoxic epidemiology study experience experimental study glucose metabolism heart damage in vivo mortality mutant nonhuman primate oxidative damage prototype targeted treatment tempol transcriptome sequencing uptake

项目摘要

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：四分之一因社区获得性肺炎 (CAP) 住院的成年人会出现心脏不良症状事件。临床流行病学研究，以及在小鼠、非人类灵长类动物中进行的研究人体尸检样本表明，CAP 的主要原因肺炎链球菌 (Spn) 可以侵入从血液中进入心脏并引起直接心脏毒性。心肌内 Spn 引起焦点区域我们称之为微损伤的损伤会破坏收缩性。我们最近取得的一项突破对 Spn 发病机制的理解是观察到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，成孔毒素肺炎球菌溶血素和链球菌丙酮酸氧化酶 (SpxB) 衍生的 H2O2 都是心脏毒性所必需的。在此，我们的目标是获得了解 Spn 摄取后心肌细胞内立即发生的事件。沿着这样的思路，体外和体内实验的结果，包括 Spn- 的双物种 RNA 测序受感染的心脏，揭示了碳可用性变化与 H2O2 之间的高度引人注目的联系产生、生物膜/心脏微病变形成和肺炎球菌溶血素产生。因此，我们假设 Spn 在心肌细胞内以及心脏微病变中遇到葡萄糖限制，导致代谢和基因表达的变化会增强细菌的心脏毒性。为了检验这个假设并学习肺炎球菌溶血素和 H2O2 如何协同作用杀死心肌细胞我们将：目标 1：确定环境葡萄糖、新陈代谢和毒力如何相互关联。阐明这些联系的基础、程度和后果，我们将：1）确定如何有目的地分流丙酮酸代谢（通过突变）对乙酸盐、乳酸和/或甲酸盐的产生产生影响高糖和低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吸收细菌后的纵向时尚及其与 Spn 变化的关系代谢; 3) 确定代谢相关基因对心肌细胞内 Spn 存活的重要性，心肌细胞的杀死，以及整个疾病过程。目标 2：确定细菌来源的 H2O2 与肺炎球菌溶血素如何杀死心肌细胞。斯普克斯B 衍生的 H2O2 和肺炎球菌溶血素都是 Spn 杀死心肌细胞所必需的；单独一个是不够的。为了确定原因，我们将： 1) 确定 H2O2 和肺炎球菌溶血素的不同产量如何共同调节心肌细胞死亡的形式； 2) 确定 H2O2 是否增强肺炎球菌溶血素的产生及其释放 Spn，或宿主细胞膜靶向； 3) 确定 SpxB 衍生的 H2O2 是否对离子有贡献此前曾被认为与肺炎球菌溶血素诱导的坏死性凋亡有关。这一目标，旨在完成后，将加深我们对 Spn 如何杀死宿主细胞的理解。