Invasion of brain endothelial cells by C. neoformans

新型隐球菌对脑内皮细胞的侵袭

• 批准号: 7248691
• 负责人: AMBROSE Y JONG
• 金额: $ 23.38万
• 依托单位: CHILDREN'S HOSPITAL OF LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7248691
• 关键词: 4-methylumbelliferone; Abbreviations; Acquired Immunodeficiency Syndrome; Actins; Adhesions; Amino Acid Sequence; Binding; Biological Models; Blocking Antibodies; Blood - brain barrier anatomy; Brain; CD44 Antigens; CD44 gene; Cell surface; Central Nervous System Infections; Cryptococcus; Cryptococcus neoformans infection; DNA Sequence Rearrangement; Development; Dose; Endothelial Cells; Genes; Genetic; Glucosamine; Goals; Human; Hyaluronan; Hyaluronic Acid; Hyaluronidase; Immune response; In Vitro; Individual; Membrane; Meningitis; Meningoencephalitis; Modeling; Morbidity - disease rate; Neuraxis; Oxidoreductase; Pathogenesis; Patients; Peptide Sequence Determination; Polysaccharides; Process; Proteins; Role; Study models; Terminology; Testing; capsule; hyaluronan synthase 1; in vivo; inhibitor/antagonist; mutant; novel strategies; pathogen; prevent; response

DESCRIPTION (provided by applicant): The long-term goal of this project is to dissect the pathogenesis of Cryptococcus meningitis. In recent years infection by Cryptococcus neoformans has increased considerably, particularly in immunocomprised individuals and AIDS patients. This pathogen has a predilection to the brain, resulting in devastating meningoencephalitis. It is unclear how C. neoformans traverses across the blood-brain barrier and causes the central nervous system infection. We propose to investigate the mechanisms of C. neoformans invasion in human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We have established in vitro and in vivo BBB models for the pathogen invasion studies. Using these model systems, we found that C. neoformans, either treated with hyaluronidase or with 4-methylumbelliferone (a hyaluronan synthase inhibitor) substantially reduced its binding ability to HBMEC. In contrast, exogenous hyaluronan was found to stimulate C. neoformans binding activity. The CPS1 protein sequence shares homology with hyaluronan synthase. The cpsl-disrupted strain lost its hyaluronan on the cell surface, and also substantially reduced its binding activity to HBMEC. Finally, anti-CD44 blocking antibody could neutralize the interaction between C. neoformans and HBMEC. Taken together, our preliminary studies suggested that the C. neoformans capsule component, hyaluronan, and HBMEC CD44 were involved in the invasion process. In this proposal, we will test the hypothesis that C. neoformans hyaluronan and HBMEC CD44 are crucial for C. neoformans pathogenesis. We will explore the mechanisms of C. neoformans invasion to HBMEC by the following Aims: First, we will examine the role of CPS1 in hyaluronan synthesis and C. neoformans invasion. Second, we will determine how C. neoformans hyaluronan contribute to the binding and invasion of HBMEC. Third, we will determine whether and how HBMEC CD44 functions as a HA receptor during C. neoformans invasion. The proposed approach will allow us to determine the role(s) of the crucial C. neoformans component, hyaluronan, and host responses during invasion. The information derived from this proposal should be helpful in the development of novel strategies to prevent C. neoformans meningitis and its associated morbidity.

描述（由申请人提供）：本项目的长期目标是剖析隐球菌脑膜炎的发病机制。近年来，新型隐球菌的感染显著增加，特别是在免疫缺陷个体和艾滋病患者中。这种病原体对大脑有偏爱，导致毁灭性的脑膜脑炎。目前还不清楚C。新生儿穿过血脑屏障并引起中枢神经系统感染。本文拟探讨C.新生儿侵袭构成血脑屏障的人脑微血管内皮细胞（HBMEC）。我们已经建立了体外和体内血脑屏障模型的病原体入侵的研究。利用这些模型系统，我们发现C.用透明质酸酶或用4-甲基伞形酮（一种透明质酸合成酶抑制剂）处理的新生儿显著降低了其与HBMEC的结合能力。相反，外源性透明质酸被发现刺激C。neoformans结合活性。CPS 1蛋白序列与透明质酸合酶具有同源性。cpsl破坏的菌株失去了其在细胞表面上的透明质酸，并且还显著降低了其与HBMEC的结合活性。抗CD 44封闭抗体可中和C.新生儿和HBMEC。综上所述，我们的初步研究表明，C。新生儿囊膜成分、透明质酸和HBMEC CD 44参与了侵袭过程。 在这个建议中，我们将测试的假设，C。新生儿透明质酸和HBMEC CD 44对C.新生儿发病机制我们将探讨C.通过以下目的研究新生儿对HBMEC的侵袭：首先，我们将研究CPS 1在透明质酸合成和C.新生物入侵 其次，我们将确定C。新生儿透明质酸有助于HBMEC的结合和侵袭。 第三，我们将确定HBMEC CD 44是否以及如何在C.新生物入侵所提出的方法将使我们能够确定关键C的作用。新生菌成分，透明质酸和宿主反应在入侵。从这一建议中获得的信息应该有助于开发新的策略来预防C。新型脑膜炎及其相关发病率。