Cytotoxic Lung Endothelial Amyloids

细胞毒性肺内皮淀粉样蛋白

• 批准号: 9760953
• 负责人: Sarah B. Voth
• 金额: $ 2.9万
• 依托单位: UNIVERSITY OF SOUTH ALABAMA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9760953
• 关键词: Alveolar; Amyloid; Amyloid beta-Protein; Attenuated; Autophagocytosis; Bacteria; Blood Circulation; Cells; Clinical; Complex; Critical Illness; Cyclic AMP; Cyclic GMP; Cyclic Nucleotides; Cytosol; Data; Disease; Endothelial Cells; Endothelium; Floods; Gases; Generations; Health; Hematogenous; Hour; Hypoxemia; Impaired cognition; Infection; Innate Immune Response; Innate Immune System; Intoxication; Lung; Lung infections; MAP3K7 gene; Mediating; Microtubules; Mus; Neurodegenerative Disorders; Nosocomial pneumonia; Organ; Outcome; Pathogenicity; Pathologic; Pathway interactions; Patients; Permeability; Phosphorylation; Phosphotransferases; Prions; Process; Production; Pseudomonas aeruginosa; Recycling; Reporting; Role; Signal Transduction; Testing; Transforming Growth Factors; Type III Secretion System Pathway; Work; antimicrobial; cytotoxic; exoenzyme; extracellular; hyperphosphorylated tau; inhibition of autophagy; novel; pathogen; prevent; respiratory; tau Proteins; tau aggregation

PROJECT SUMMARY/ABSTRACT Pulmonary endothelial barrier integrity is vital for efficient gas exchange and to prevent the hematogenous dissemination of respiratory pathogens. Pseudomonas aeruginosa, a predominant agent of nosocomial pneumonia, breaches the endothelial barrier by inducing junctional complex disruption leading to alveolar flooding and hypoxemia. Here, we propose to study a previously unidentified, novel disease process defined by the interaction of the common nosocomial pathogen, P. aeruginosa, with the host endothelium. P. aeruginosa utilizes a Type III Secretion System (T3SS) to inject cytotoxic exoenzymes directly into the host cell. Exoenzyme Y (ExoY), a T3SS effector expressed by ~90% of clinical P. aeruginosa strains, causes marked increases in cytosolic cGMP, cUMP, and cAMP. The increase in cAMP facilitates the phosphorylation of an endothelial tau, which dissociates from microtubules, followed by microtubule collapse, interendothelial gap formation, and increased permeability. Hyperphosphorylated tau then coalesces into cytotoxic tau oligomers that are released into the extracellular milieu. These cytotoxic tau oligomers are transmissibleand self-propagating amyloid prions. The respective roles of cGMP and cUMP are currently unknown, although preliminary data establishes both a temporal and spatial correlation between the increase in ExoY-generated cUMP and oligomeric tau release from PMVECs. The cUMP signal in the bulk cytosol closely coincides with both the reduction of cytosolic tau and the concomitant increase of extracellular tau. Thus, an ExoY-instigated increase in cUMP is implicated in the export of cytotoxic tau. Furthermore, within the context of neurodegenerative disease, the degradation and recycling pathway of autophagy is often pathologically constrained thereby preventing the breakdown of excess or dysregulated amyloids. Following the inhibition of autophagic flux, dysregulated amyloids accumulate and oligomerize. Clearance of nascent tau oligomers is often facilitated via exosomal and/or secretion mediated export. Concordant with our observations, ExoY has recently been implicated in the suppression of the innate immune response via the inhibition of transforming growth factor-β-activating kinase 1 (TAK1) which has also been reported to obstruct autophagy. Taken together, ExoY suppression of TAK1 in PMVECs may contribute to the inhibition of autophagy and the production of infection-induced tau prions. Therefore, this proposal tests the hypothesis that ExoY-induced cUMP contributes to the suppression of autophagic flux thereby promoting the generation and release of cytotoxic tau that transmissibly disrupts interendothelial junctions and promotes perm eability. .

项目概要/摘要 肺内皮屏障的完整性对于有效的气体交换和防止血行反应至关重要 呼吸道病原体的传播。铜绿假单胞菌，院内感染的主要病原体 肺炎，通过诱导连接复合体破坏而突破内皮屏障，导致肺泡 洪水和低氧血症。在这里，我们建议研究一种以前未识别的新型疾病过程，其定义为 常见的医院病原体铜绿假单胞菌与宿主内皮细胞的相互作用。铜绿假单胞菌 利用 III 型分泌系统 (T3SS) 将细胞毒性外切酶直接注射到宿主细胞中。胞外酶 Y (ExoY) 是一种 T3SS 效应子，约 90% 的临床铜绿假单胞菌菌株表达，可导致 胞质 cGMP、cUMP 和 cAMP。 cAMP 的增加促进内皮 tau 蛋白的磷酸化， 从微管解离，然后微管塌陷，内皮间隙形成， 增加渗透性。然后，过度磷酸化的 tau 蛋白结合成细胞毒性 tau 寡聚体并释放 进入细胞外环境。这些细胞毒性 tau 寡聚体是可传播且自我繁殖的淀粉样蛋白朊病毒。 尽管初步数据表明 cGMP 和 cUMP 各自的作用目前尚不清楚 ExoY 产生的 cUMP 增加与寡聚 tau 释放之间的时间和空间相关性 PMVEC。大量胞质中的 cUMP 信号与胞质 tau 的减少和 细胞外 tau 蛋白随之增加。因此，ExoY 引发的 cUMP 增加与出口有关 细胞毒性 tau 蛋白。此外，在神经退行性疾病的背景下，降解和回收 自噬途径通常受到病理学限制，从而防止过量或 淀粉样蛋白失调。自噬流受到抑制后，失调的淀粉样蛋白会积累并 低聚。新生 tau 寡聚体的清除通常通过外泌体和/或分泌介导来促进 出口。与我们的观察一致，ExoY 最近与先天性的抑制有关 通过抑制转化生长因子-β-激活激酶 1 (TAK1) 产生免疫反应，该激酶也具有 据报道可阻碍自噬。综上所述，PMVEC 中 TAK1 的 ExoY 抑制可能有助于 抑制自噬和感染诱导的 tau 朊病毒的产生。因此，本提案测试了 假设 ExoY 诱导的 cUMP 有助于抑制自噬流，从而促进 细胞毒性 tau 蛋白的产生和释放，可传播性破坏内皮间连接并促进 烫发能力。 。