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Brucei Gambiense和T.B.引起的人类疾病的神经系统并发症。罗德西氏菌归因于锥虫中枢神经系统的渗透。然而，非洲锥虫如何穿越血脑屏障（BBB）仍然是一个尚未解决的问题。使用由人脑微血管内皮细胞（BMEC）构建的体外BBB模型，我们发现血液形式（BSF）T。b。 Gambiense寄生虫在细胞间连接处或附近结合，并比动物感染性T. b更有效地穿越体外BBB模型。布鲁西。即使在BSF寄生虫存在的情况下，昆虫感染性的Procyclics也不会结合或跨BMEC。人类感染性BSF诱导BMEC中细胞内钙（[Ca2+] I）水平的非常快速的短暂性或振荡变化。单层完整性的早期变化来自跨内皮电阻的实时测量（TEER），虽然很快，但在观察到[Ca2+]的变化后发生了。使用PLC抑制剂U73211对人BMEC进行预处理会增加人类BMEC跨内皮电阻（TEER），抑制锥虫诱导的BMEC [Ca2+] J水平的变化，并抑制整个障碍物的锥虫体迁移。由于我们的[CA2+] J研究也表明了Bradykinin的可能作用，因此我们计划与巴西对应物一起研究这种可能性。因此，该FIRCA提案的具体目的是确定非洲锥虫相关蛋白酶和动力蛋白受体在人BMEC激活中的作用。这项研究将主要在巴西联邦联邦大学里奥德·贾尼罗（Julio Scharfstein）作为NIH授予1 RO1 AI51464-01的延伸。从拟议的研究中获得的结果将是我们理解非洲锥虫入侵大脑的最初事件的重要一步。 有了这些知识，我们将为设计疗法做好准备，以阻止寄生虫进入大脑并防止许多痛苦的神经系统症状，最终导致死亡。