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：
10659249
负责人：
JOHN STEPHEN Dumler
金额：
$ 18.98万
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/10659249
关键词：
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 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 Invaded Investigation Link Lung Lyme Disease Measures Membrane Metabolic Mexico Microscopy Molecular Monitor Multiple Organ Failure Myosin Light Chain Kinase Nutrient Nutritional Organ Organism PIK3CG gene PMCA1 protein Parasites Pathogenicity Pathologic Permeability Phospholipase Phosphorylation Phosphotransferases Preventive therapy Process Production Proliferating 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 Endothelial Cell Vascular Permeabilities Virulence Visualization Work adverse outcome antagonist blood perfusion cadherin 5 calcium-dependent protein kinase cell motility chelation design electric impedance fitness hypoperfusion improved inhibitor ischemic injury microbial monolayer parasitism pathogen pharmacologic 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.

项目摘要/摘要斑点发烧组立克斯（SFGR）是美国第二常见的tick传播感染，考虑到严重的疾病和死亡，世界许多地区的病例死亡率超过10％。岩石山斑发烧是这一组的原型疾病，主要病理生理不良后果是血管渗透性增加，导致肺，大脑和其他肺部缺血性和缺血性损伤器官。 SFG人力素体感染了内皮细胞，并使宿主ATP寄生以生长和扩散。我们的初步研究表明使用钙螯合剂或特定钙调节感染内皮细胞屏障中钙通量的调节通道阻滞剂废除了血管通透性。我们建议发现发烧的人力体利用营养病毒通过获得的“通道疗法”颠覆宿主钙处理的策略，该策略可以增加进入细胞的机会代谢底物，但这反过来损害了内皮细胞的关键功能。我们的假设是增加 Rickettsiae的细胞ATP竞争会损害ATP依赖的Ca2+泵，从而导致增加细胞内钙浓度，Ca2+通道的激活，Ca2+依赖性激酶，信号通路和转录调节增加了立克生长的关键营养素的细胞含量。改善的后果人力素的适应性最终导致细胞骨骼的重组，拆卸内皮连接的拆卸以及不可避免地，血管渗透性增加。该提案将测量细胞内钙和ATP浓度钙通道阻滞剂的存在或不存在，同时在两种早期监测内皮屏障功能障碍时以及立克帕克里（Rickettsia Parkeri）感染的晚期。钙通量在立克血管通透性中的作用的证据包括局部钙的“泡芙”，随着瞬态局灶性胞质ATP部署和局部细胞骨架重组入侵事件。预计之后将是细胞内钙的全球增加，ATP部署，恢复细胞骨架，并与大量的立克性增殖，对通过螯合，关键钙通道的阻塞或沉默来缓冲胞质钙浓度。立克还将确定负载以了解这些操纵对微生物适应性的影响。这项工作将确定允许通过斑点发烧的立克感染变化血管通透性的关键机制，也许是由立克效应子蛋白，以及基于宿主的药学干预措施的潜在靶标，以防止严重和致命 SFGR的结果以及潜在的其他传染病。