Role of mTOR signaling in endothelial responses to Rickettsia rickettsii infection.

mTOR 信号传导在内皮细胞对立克次体感染反应中的作用。

• 批准号: 10097995
• 负责人: Abha Sahni
• 金额: $ 19.75万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-04 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10097995
• 关键词: 1-Phosphatidylinositol 3-Kinase; Address; Adhesions; Adhesives; Anti-Inflammatory Agents; Area; Autophagocytosis; Biological; Blood Vessels; C3H/HeN Mouse; CCL2 gene; Cell Communication; Cells; Cellular Metabolic Process; Cellular biology; Clinical Trials; Communicable Diseases; Complex; Disease; Disease Outbreaks; Edema; Endothelial Cells; Endothelium; Equilibrium; Exploratory/Developmental Grant; FDA approved; FRAP1 gene; Functional disorder; Genetic Transcription; Granulocyte Colony-Stimulating Factor; Growth; Health; Host Defense Mechanism; Human; IL8 gene; Immune response; In Vitro; Incidence; Infection; Inflammation; Inflammatory; Inflammatory Response; Innate Immune Response; Intercellular Adhesion Molecules; Intercellular adhesion molecule 1; Interleukin-1 alpha; Interleukin-10; Interleukin-6; Interleukins; Iowa; Kinetics; Knowledge; Laboratories; Liquid substance; Location; Mediator of activation protein; Modeling; Molecular; Molecular Biology; Mus; Mutation; Natural Immunity; Nuclear; Organ; Pathogenesis; Pathogenicity; Pharmaceutical Preparations; Pharmacology; Phase; Phenotype; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Play; Process; Protein-Serine-Threonine Kinases; Proteobacteria; Proto-Oncogene Proteins c-akt; Publishing; Raptors; Regulation; Resistance; Rickettsia; Rickettsia Infections; Rickettsia conorii; Rickettsia rickettsii; Rocky Mountain Spotted Fever; Role; STAT protein; Signal Pathway; Signal Transduction; Stat3 protein; Structure; Subgroup; Therapeutic; Ticks; Tissues; Transcriptional Activation; Translation Initiation; Tropism; Vascular Cell Adhesion Molecule-1; Vascular Permeabilities; Vasculitis; Virulence; Virulent; Work; Zoonoses; base; chemokine; combat; cytokine; disease transmission; extracellular; high reward; high risk; in vivo; in vivo Model; inhibitor/antagonist; innovation; insight; interdisciplinary approach; mortality; mouse model; neglect; novel; novel therapeutics; pathogen; pathogenic microbe; recruit; response; spotted fever; tick transmission; transcription factor; vector mosquito; vector-borne infection; virtual

PROJECT SUMMARY/ABSTRACT Rickettsioses as infectious diseases stand out for their historic and continued impact on the global human health. Rocky Mountain spotted fever due to tick-transmitted Rickettsia rickettsii (Rr), a Gram-negative obligate intracellular α-proteobacterium, is one of the most severe rickettsioses and a notifiable illness in the USA. An important determinant of disease pathogenesis in humans and established laboratory models of infection is disseminated infection of microvascular endothelial cell lining of blood vessels, resulting in ‘rickettsial vasculitis’ defined by inflammation of the vasculature and compromised vascular permeability leading to tissue fluid imbalance and edema of vital organs. Rr-induced endothelial responses include acquisition of pro-adhesive, pro-coagulant, and pro-inflammatory phenotypes and activation of master transcription regulator nuclear factor- κB, yet the mechanisms underlying determination of innate immune responses and host cell fate represent a neglected area of fundamental relevance. Notably, potential roles of autophagy as a ‘double-edged’ host defense mechanism capable of supporting intracellular pathogens, anti-inflammatory endothelial responses to minimize vascular damage and dysfunction, and the balance of pro- vis-à-vis anti-inflammatory signaling as the biological basis of rickettsial virulence represent unexplored arenas of scientific enquiry. We present evidence suggesting increased phosphorylation of signal transducer and activator of transcription protein STAT3, a response coinciding with the onset of autophagy and activation of mechanistic target of rapamycin (mTOR) complexes C1 and C2 during Rr infection of human endothelial cells. Our intriguing preliminary findings and extensive published work on Rr-induced transcriptional activation serve as the basis of our hypothesis that mTOR functions as a central regulatory determinant of the balance of pro-inflammatory/pro-adhesive vis-a-vis anti-inflammatory innate immune responses of Rr-infected endothelium. Considering that mTOR signaling involves two structurally and functionally distinct complexes, Aim 1 will address the fundamentally important definition of the activation status of mTORC1 and mTORC2 during endothelial infection with Rr strains of varying virulence and determine the effects of their inhibition on host cell autophagy and rickettsial replication. Aim 2 will then decipher potentially differential roles of mTORC1 and C2 in infection-induced inflammatory signaling. We will strategically employ contemporary, cutting-edge, and interdisciplinary approaches of cell and molecular biology to gain new and unique insights into host mTORC1/C2 activation in correlation with rickettsial virulence and their roles in governing innate immune responses via regulation of autophagy and pro- /anti-inflammatory signaling using in vitro and in vivo models of infection. The proposed analysis of pathogen interactions with novel signaling checkpoints capable of regulating beneficial and/or detrimental host responses will guide innovative therapeutic strategies to combat the sequelae associated with (re)emerging rickettsioses.

项目概要/摘要 立克次体作为传染病因其对全球人类的历史性和持续影响而引人注目 健康。由蜱传播的立克次体 (Rr) 引起的落基山斑疹热，一种革兰氏阴性专性立克次体 细胞内α-变形杆菌是最严重的立克次体病之一，也是美国的法定疾病。一个 人类疾病发病机制和已建立的感染实验室模型的重要决定因素是 血管微血管内皮细胞内壁的播散性感染，导致“立克次体血管炎” 由脉管系统炎症和血管通透性受损导致组织液定义 重要器官的不平衡和水肿。 Rr 诱导的内皮反应包括获得亲粘附、 促凝血和促炎表型以及主转录调节核因子的激活- κB，但决定先天免疫反应和宿主细胞命运的机制代表了 被忽视的基本相关领域。值得注意的是，自噬作为“双刃”宿主的潜在作用 能够支持细胞内病原体、抗炎内皮反应的防御机制 最大限度地减少血管损伤和功能障碍，以及抗炎信号传导的平衡 立克次体毒力的生物学基础代表了科学探究的未探索领域。我们提出证据 表明信号转导子和转录蛋白 STAT3 激活剂的磷酸化增加， 反应与自噬的开始和雷帕霉素机械靶标（mTOR）的激活同时发生 Rr 感染人内皮细胞期间复合物 C1 和 C2。我们有趣的初步发现和 关于 Rr 诱导的转录激活的大量已发表的工作是我们假设的基础： mTOR 作为促炎/促粘附平衡的中心调节决定因素 Rr 感染内皮细胞的抗炎先天免疫反应。考虑到 mTOR 信号传导 涉及两个结构和功能不同的复合体，目标 1 将解决根本上重要的问题 Rr菌株内皮感染期间mTORC1和mTORC2激活状态的定义 不同的毒力并确定它们对宿主细胞自噬和立克次体复制的抑制作用。 目标 2 将破译 mTORC1 和 C2 在感染诱导的炎症中的潜在差异作用 发信号。我们将战略性地采用当代、尖端和跨学科的细胞和 分子生物学，以获得与宿主 mTORC1/C2 激活相关的新的、独特的见解 立克次体毒力及其通过调节自噬和亲细胞在控制先天免疫反应中的作用 /使用体外和体内感染模型的抗炎信号传导。拟议的病原体分析 与能够调节有益和/或有害宿主反应的新型信号检查点的相互作用 将指导创新的治疗策略，以对抗与（重新）出现的立克次体病相关的后遗症。

项目成果

Comparative transcriptomic analysis of Rickettsia conorii during in vitro infection of human and tick host cells.

• DOI: 10.1186/s12864-020-07077-w
• 发表时间: 2020-09-25
• 期刊: BMC genomics
• 影响因子: 4.4
• 作者: Narra HP;Sahni A;Alsing J;Schroeder CLC;Golovko G;Nia AM;Fofanov Y;Khanipov K;Sahni SK
• 通讯作者: Sahni SK

Activation of Mechanistic Target of Rapamycin (mTOR) in Human Endothelial Cells Infected with Pathogenic Spotted Fever Group Rickettsiae.

• DOI: 10.3390/ijms21197179
• 发表时间: 2020-09-29
• 期刊: International journal of molecular sciences
• 影响因子: 5.6
• 作者: Sahni A;Narra HP;Sahni SK
• 通讯作者: Sahni SK