The molecular basis for the translocation of fungi from blood-to-brain.

真菌从血液转移到大脑的分子基础。

• 批准号: 10330006
• 负责人: ANGIE GELLI
• 金额: $ 36.12万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-15 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10330006
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Area; Aspergillus; Autopsy; Binding; Blood; Brain; Brain Injuries; CD44 gene; Candida albicans; Cause of Death; Cells; Central Nervous System Agents; Central Nervous System Fungal Infections; Central Nervous System Infections; Cessation of life; Chronic; Coccidioides; Columbidae; Complex; Cryptococcus; Cryptococcus neoformans; Cryptococcus neoformans infection; Cystic Lesion; Cytoskeleton; Data; Development; Disease; Drops; Elements; Endocytosis; Endothelium; Environment; Fungal Spores; Goals; Health; Histoplasma capsulatum; Hospitalization; Human; In Vitro; Infection; Inhalation; Knock-out; Knowledge; Label; Lead; Mediating; Meningoencephalitis; Mission; Modeling; Molecular; Morbidity - disease rate; Movement; Mucor; Nature; Neuraxis; Pathogenesis; Pathologic; Pathway interactions; Patients; Permeability; Pharmaceutical Preparations; Process; Proliferating; Publishing; Receptor Protein-Tyrosine Kinases; Regulation; Reporting; Reproduction spores; Research; Risk; Role; Route; Series; Signal Transduction; Soil; Structure of parenchyma of lung; Technology; Testing; Time; Transactivation; Trees; United States National Institutes of Health; Work; aerosolized; blood-brain barrier crossing; blood-brain barrier permeabilization; brain endothelial cell; design; experimental study; fungus; improved; in vivo; innovation; migration; mortality; mouse model; neurotropic; novel strategies; novel therapeutics; pathogen; pathogenic fungus; prevent; prophylactic; recruit; response; spatiotemporal; trafficking

PROJECT ABSTRACT Infections of the central nervous system (CNS) caused by fungi have the highest morbidity and mortality when compared to other causative agents of CNS infections. Cryptococcus neoformans (Cn), Candida albicans, Aspergillus spp., Mucor, Coccidioides spp., and Histoplasma capsulatum are the most common cause of fungal brain infections resulting in a chronic instead of an acute or subacute meningoencephalitis. The long-term goal will investigate the spatio-temporal organization and molecular basis of Cn trafficking across the BBB and investigate a cross-talk between a transcellular mechanism and the opening of a paracellular path in response to Cn infection. Given our preliminary data and published studies, we propose that Cn represents an excellent model pathogen with which to determine the mechanisms that pathogenic fungi use to breach the BBB and enter the CNS. In our efforts to understand the molecular basis mediating the Cn-brain endothelium interactions, we identified a tyrosine kinase receptor (EphA2-TKR) as the central player. The central hypothesis states that fungal cells penetrate the BBB by engaging EphA2-TKR in order to access a binary path into the CNS. To test our hypothesis, we will investigate the interplay between fungal cells, EphA2-TRK and its downstream signaling components in mediating the translocation of Cn from blood-to-brain. The following specific aims will test the hypothesis: SA1 will investigate a Cn-induced CD44-mediated transactivation of EphA2-TKR activity and the interactome of EphA2-TKR. SA2 will examine the role of EphA2-TKR in upregulating vesicular traffic of Cn and resolve whether Cn-induced activity of EphA2-TKR promotes a co-regulation of a transcellular and paracellular pathway. SA3 will resolve the contribution of EphA2-TKR activity to the translocation of Cn from blood-to-brain in vivo and examine the molecular basis of changes in the permeability of the BBB when challenged by Cn. The proposed research is innovative because it will for the first time, detail the key players that promote the internalization and trafficking of fungi across the BBB. The innovation extends to our published studies that identified EphA2-TKR in the brain endothelium as a central element in mediating the migration Cn from blood-to-brain. This along with the notion that crossing of the BBB is initiated by a fungal-induced CD44-transactivation of EphA2-TKR to trigger a pathological use of endocytosis (and possibly a secondary paracellular path) in brain endothelial cells is a paradigm shift from our current understanding. We have proposed experiments that will use multiple complementary approaches to tease apart the molecular interaction between Cn, EphA2- TKR and CD44 while also using proximity-dependent labeling to identify the interactome of EphA2-TKR. The knowledge gained from our studies will make a significant contribution to fungal pathogenesis of the CNS, because it remains significantly understudied, and this work will spearhead the development of molecules that could block fungal entry and thus serve as pre- emptive or prophylactic therapy in patients at risk for developing fungal meningoencephalitis.

项目摘要 由真菌引起的中枢神经系统（CNS）感染的发病率最高， 与中枢神经系统感染的其他病原体相比，死亡率更高。新型隐球菌 (Cn)、白色念珠菌、曲霉属、毛霉菌、球孢子菌属和荚膜组织胞浆菌 是导致脑部真菌感染的最常见原因，导致慢性而不是急性 或亚急性脑膜脑炎。长期目标将调查时空 Cn 跨 BBB 贩运的组织和分子基础并调查串扰 跨细胞机制和响应 Cn 的细胞旁路径开放之间的关系 感染。根据我们的初步数据和已发表的研究，我们建议 Cn 代表 优秀的模型病原体，用于确定致病真菌利用的机制 突破血脑屏障并进入中枢神经系统。在我们努力了解介导的分子基础的过程中 Cn-脑内皮相互作用，我们鉴定了酪氨酸激酶受体（EphA2-TKR） 核心球员。中心假设指出，真菌细胞通过接合来穿透血脑屏障 EphA2-TKR，以便访问 CNS 的二进制路径。为了检验我们的假设，我们将 研究真菌细胞、EphA2-TRK 及其下游信号传导之间的相互作用 介导 Cn 从血液到大脑易位的成分。具体目标如下 将检验假设：SA1 将研究 Cn 诱导的 CD44 介导的反式激活 EphA2-TKR 活性和 EphA2-TKR 的相互作用组。 SA2 将检查 EphA2-TKR 的作用 上调 Cn 的囊泡运输并解决 Cn 是否诱导 EphA2-TKR 活性 促进跨细胞和细胞旁途径的共同调节。 SA3将解决 EphA2-TKR活性对体内Cn从血液到大脑易位的贡献 检查 BBB 受到 Cn 挑战时渗透性变化的分子基础。 拟议的研究具有创新性，因为它将首次详细介绍关键参与者 促进真菌跨 BBB 的内化和贩运。创新延伸到我们的 已发表的研究表明，脑内皮细胞中的 EphA2-TKR 是 介导 Cn 从血液到大脑的迁移。这与跨越 BBB 由真菌诱导的 EphA2-TKR 的 CD44 反式激活启动，从而引发病理性的 在脑内皮细胞中使用内吞作用（可能是次要的旁细胞路径）是一种 我们当前理解的范式转变。我们提出了实验，将使用 多种互补方法来梳理 Cn、EphA2- 之间的分子相互作用 TKR 和 CD44，同时还使用邻近依赖性标记来识别 EphA2-TKR。从我们的研究中获得的知识将为真菌做出重大贡献 中枢神经系统的发病机制，因为它仍然没有得到充分研究，这项工作将 率先开发出可以阻止真菌进入的分子，从而作为预 对有发生真菌性脑膜脑炎风险的患者进行预防性治疗。