Blood-brain barrier traversal by African trypanosomes

非洲锥虫穿越血脑屏障

• 批准号: 6883609
• 负责人: Dennis John Grab
• 金额: $ 4.03万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-15 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6883609
• 关键词: Brazil; Trypanosoma brucei; blood brain barrier; digital imaging; endopeptidases; enzyme activity; enzyme linked immunosorbent assay; fluorescence microscopy; host organism interaction; human tissue; intracellular parasitism; kinins; membrane permeability; neuropeptide receptor; pathologic process; phosphorylation; polymerase chain reaction; receptor binding; vascular endothelium

DESCRIPTION (provided by applicant) The neurological complications of sleeping sickness in man caused by Trypanosoma brucei gambiense and T.b. rhodesiense are attributed to the penetration of the central nervous system by trypanosomes. Yet, how African trypanosomes cross the blood-brain barrier (BBB) remains an unresolved issue. Using our in vitro BBB model constructed of human brain micro vascular endothelial cells (BMEC), we find that bloodstream form (BSF) T. b. gambiense parasites bind at or near intercellular junctions and cross the in vitro BBB model paracellularly more efficiently than do animal infective T. b. brucei. Insect infective procyclics do not bind nor cross BMEC even in the presence of BSF parasites. Human infective BSF induce very rapid transient or oscillatory changes in intracellular calcium ([Ca2+]i) levels in BMEC. The early changes in monolayer integrity from real-time measurements of transendothelial electrical resistance (TEER), though rapid, occur after the observed changes in [Ca2+];. Pretreatment of human BMEC with the PLC inhibitor U73211 increases human BMEC transendothelial electrical resistance (TEER), inhibits the trypanosome-induced changes in BMEC [Ca2+]j levels, and inhibits trypanosome transmigration across the barrier. Because our [Ca2+]j studies also suggest a possible role for bradykinin, we plan to investigate this possibility with our Brazilian counterparts. The Specific Aim for this FIRCA proposal therefore will be to determine the role of African trypanosome-associated proteases and kinin-receptors in human BMEC activation. This research will be done primarily in Brazil at Universidade Federal do Rio de Janeiro with Julio Scharfstein as an extension of NIH grant # 1 RO1 AI51464-01. The results obtained from the proposed study will be an important step in our understanding of the initial events of African trypanosome invasion into the brain. Armed with this knowledge we will be better prepared to design therapies that will stop the parasites from entering the brain and prevent many of the agonizing neurological symptoms, which eventually lead to death.

描述(由申请人提供) 由布氏冈比亚锥虫和结核杆菌引起的人类昏睡病的神经系统并发症。罗氏菌是由于锥虫穿透中枢神经系统所致。然而，非洲锥虫如何跨越血脑屏障(BBB)仍然是一个悬而未决的问题。利用我们构建的人脑微血管内皮细胞(BMEC)体外BBB模型，我们发现血流形式(BSF)冈比亚弓形虫在细胞间连接处或附近结合，并通过体外BBB模型比动物感染布氏锥虫更有效。即使在BSF寄生虫存在的情况下，昆虫感染性前循环也不能结合或交叉BMEC。人感染的BSF可引起BMEC细胞内钙离子([Ca~(2+)]_i)的快速、瞬时或振荡变化。通过实时测量跨内皮细胞电阻(TEER)，单层完整性的早期变化虽然很快，但发生在观察到的[Ca~(2+)]；变化之后。用PLC抑制剂U73211预处理人BMEC可增加人BMEC的跨内皮细胞电阻(TEER)，抑制锥虫引起的BMEC[Ca~(2+)]j水平的变化，并抑制锥虫跨屏障迁移。由于我们的[Ca~(2+)]j研究也表明缓激肽可能起作用，我们计划与巴西同行一起研究这种可能性。因此，FIRCA建议的具体目的将是确定非洲锥虫相关蛋白和激动素受体在人BMEC激活中的作用。这项研究将主要在巴西里约热内卢联邦大学进行，胡里奥·沙尔夫斯坦将作为NIH#1 RO1 AI51464-01的延伸。拟议的研究结果将是我们理解非洲锥虫入侵大脑的初始事件的重要一步。有了这些知识，我们将更好地准备设计治疗方法，阻止寄生虫进入大脑，并防止许多令人痛苦的神经症状，这些症状最终会导致死亡。