Host Ca2+, actin, and ATP production in rickettsia-endothelial cell dysfunction

立克次体内皮细胞功能障碍中宿主 Ca2、肌动蛋白和 ATP 的产生

基本信息

批准号：
10509838
负责人：
JOHN STEPHEN Dumler
金额：
$ 22.78万
依托单位：
HENRY M. JACKSON FDN FOR THE ADV MIL/MED
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：
2022-07-05 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10509838
关键词：
1-Phosphatidylinositol 3-Kinase ATP phosphohydrolase Actin-Binding Protein Actins Actomyosin Adenine Nucleotide Translocase Affect Bacteria Blood Vessels Brain Brazil Buffers Ca(2+)-Transporting ATPase Calcium Calcium Channel Calcium Channel Blockers Calmodulin Case Fatality Rates Cation Pumps Cell Death Cell Line Cell physiology Cells Cellular Structures Cessation of life Chelating Agents Colombia Communicable Diseases Consequentialism Consumption Cytoskeleton Cytosol Data Disease Endoplasmic Reticulum Endothelial Cells Endothelium Energy-Generating Resources Event Fatal Outcome Functional disorder Genetic Transcription Genome Germ Cells Goals Growth Human Hypotension Impairment In Vitro Infection Intervention Investigation Link Lung Lyme Disease Measures Membrane Metabolic Mexico Microscopy Molecular Monitor Multiple Organ Failure Myosin Light Chain Kinase Nutrient Nutritional Organ Organism PMCA1 protein Parasites Pathogenicity Pathologic Permeability Pharmacology Phospholipase Phosphorylation Phosphotransferases Preventive therapy Process Production Property Proteins Pump Regulation Research Resolution Resources Rickettsia Rickettsia Infections Rickettsia parkeri Rickettsia rickettsii Rocky Mountain Spotted Fever Role Sepsis Shock Signal Pathway Signaling Molecule Small Interfering RNA System Tick-Borne Infections Time Transcriptional Regulation Vascular Permeabilities Virulence Work adverse outcome antagonist base blood perfusion cadherin 5 calcium-dependent protein kinase cell motility chelation design electric impedance fitness hypoperfusion improved inhibitor ischemic injury microbial monolayer parasitism pathogen prevent receptor recruit release of sequestered calcium ion into cytoplasm response spotted fever temporal measurement voltage

项目摘要

Project Summary/Abstract Spotted fever group rickettsioses (SFGR) are in aggregate the second most common tick-borne infections in the U.S. and account for considerable severe disease and death, with case fatality rates over 10% in many regions of the world. Rocky Mountain spotted fever is the prototypical disease in this group for which the major pathophysiologic adverse consequence is increased vascular permeability, leading to hypotension, hypoperfusion, and ischemic injury to the lungs, brain and other organs. SFG rickettsiae infect endothelial cells and parasitize host ATP for growth and spread. Our preliminary studies showed that regulation of calcium flux in infected endothelial cell barriers using calcium chelators or specific calcium channel blockers abrogates vascular permeability. We propose that spotted fever rickettsiae utilize a nutritional virulence strategy to subvert host calcium handling – through an acquired “channelopathy” - that drives increases in access to cellular metabolic substrates, but that in turn damages key functions of endothelial cells. Our hypothesis is that increasing competition for cellular ATP by rickettsiae impairs ATP-dependent Ca2+ pumps, which in turn leads to increased intracellular calcium concentrations, activation of Ca2+ channels, Ca2+-dependent kinases, signaling pathways and transcriptional regulation that increase cellular content of key nutrients for rickettsial growth. The consequences of improved rickettsial fitness ultimately leads to reorganization of cellular cytoskeleton, disassembly of inter-endothelial junctions, and inevitably, increased vascular permeability. The proposal will measure intracellular calcium and ATP concentrations in the presence or absence of calcium channel-blocking agent, while monitoring for endothelial barrier dysfunction in both early and late stages of Rickettsia parkeri infection. Evidence of a role for calcium flux in rickettsial vascular permeability includes localized calcium “puffs” with transient focal cytosolic ATP depletion and local cytoskeletal restructuring as early post-invasion events. This is predicted to be followed by global increases in intracellular calcium, ATP depletion, cytoskeleton restructuring, and inter-endothelial junction disassembly with massive rickettsial proliferation, sensitive to buffering cytosolic calcium concentrations through chelation or blocking or silencing of key calcium channels. Rickettsial load will also be determined to understand the effect of these manipulations on microbial fitness. This work will identify key mechanisms that permit changes in vascular permeability with spotted fever rickettsia infection, perhaps driven by rickettsial effector proteins, and potential targets for host-based pharmacologic intervention to prevent severe and fatal outcomes of SFGR and potentially other infectious diseases.

项目概要/摘要斑点热群立克次体病 (SFGR) 总体上是美国第二大常见的蜱传感染，造成相当多的严重疾病和死亡，世界许多地区的病死率超过 10%。山斑热是该群体的典型疾病，其主要病理生理不良后果血管通透性增加，导致低血压、低灌注以及肺、脑和其他部位的缺血性损伤我们的初步研究表明，SFG 立克次体感染内皮细胞并寄生于宿主 ATP 上以进行生长和传播。表明使用钙螯合剂或特定钙调节受感染内皮细胞屏障中的钙通量我们认为斑疹热立克次体利用了营养毒力。颠覆宿主钙处理的策略——通过获得性“通道病”——推动细胞进入细胞的机会增加代谢底物，但这反过来又损害内皮细胞的关键功能。我们的假设是增加。立克次体对细胞 ATP 的竞争会损害 ATP 依赖性 Ca2+ 泵，进而导致细胞内钙浓度、Ca2+ 通道激活、Ca2+ 依赖性激酶、信号通路和增加立克次体生长关键营养素的细胞含量的转录调节。立克次体适应性最终导致细胞骨架的重组、内皮细胞间连接的分解以及不可避免地，血管通透性增加，该提案将测量细胞内的钙和 ATP 浓度。存在或不存在钙通道阻滞剂，同时监测早期和早期的内皮屏障功能障碍。钙流在立克次体血管通透性中作用的证据。包括局部钙“膨胀”以及短暂的局灶性细胞质 ATP 消耗和早期局部细胞骨架重组预计随后会发生入侵后事件，细胞内钙、ATP 消耗全面增加，细胞骨架重组和内皮连接分解伴随大量立克次体增殖，对通过螯合或阻断或沉默关键的立克次体来缓冲胞质钙浓度。还将确定负载以了解这些操作对微生物适应性的影响。斑疹热立克次体感染导致血管通透性发生变化的关键机制，可能是由立克次体效应蛋白，以及基于宿主的药物干预的潜在目标，以预防严重和致命 SFGR 和潜在其他传染病的结果。