Choroid Plexus as a Target in Metal-Induced Neurotoxicity

脉络丛作为金属诱导神经毒性的靶点

• 批准号: 7536391
• 负责人: WEI ZHENG
• 金额: $ 33.37万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7536391
• 关键词: 3' Untranslated Regions; Affect; Area; Binding; Biological Assay; Biological Markers; Blood; Blood - brain barrier anatomy; Blood capillaries; Body Fluids; Brain; Carrier Proteins; Cell Line; Cell membrane; Cells; Cerebrospinal Fluid; Chronic; Confocal Microscopy; Disease; Electrophoretic Mobility Shift Assay; Epithelial; Epithelium; Exposure to; Ferritin; Functional disorder; Funding; Gene Expression; Gene Silencing; Genetic Transcription; Goals; Grant; Heterogeneous Nuclear RNA; Homeostasis; Human; In Vitro; Iron; Iron Regulatory Protein 1; Iron-Regulatory Proteins; Kinetics; Laboratory Research; Location; Manganese; Messenger RNA; Metabolic Diseases; Metals; Modeling; Molecular; Neurodegenerative Disorders; Neurons; Nuclear; Parkinson Disease; Parkinsonian Disorders; Peer Review; Perfusion; Population; Progress Reports; Proteins; RNA; Rattus; Regulation; Reporting; Research; Research Personnel; Research Support; Reverse Transcriptase Polymerase Chain Reaction; Role; Rotenone; Running; SLC11A2 gene; Serum; Side; Small Interfering RNA; Steel; Structure; Structure of choroid plexus; Study Section; System; Techniques; Testing; Time; Transferrin Receptor; US Army Medical Research and Material Command; Welding; Western Blotting; base; blood cerebrospinal fluid barrier; capillary; career; divalent metal; early onset; in vivo; insight; knock-down; mRNA Transcript Degradation; metal transporting protein 1; neurotoxicity; novel; programs; research study; stem; toxicant; uptake

DESCRIPTION (provided by applicant): Altered brain iron (Fe) homeostasis has been shown in idiopathic Parkinson's disease (IPD) and in manganese (Mn)-induced Parkinsonism. The current proposal continues the central theme of our long-time research goal, i.e., to explore the role of brain barrier systems in metal-induced neurotoxicities. Divalent metal transporter-1 (DMT1) and metal transport protein-1 (MTP1) are two newly discovered metal transporters and function to transport metals across the cell membrane. In the Progress Report, we have demonstrated the presence of DMT1 and MTP1 in the choroid plexus, where the blood-cerebrospinal fluid (CSF) barrier (BCB) is located. We have also observed that Mn exposure increases DMT1 expression and mobilizes subcellular MTP1 in the BCB epithelia. However, the questions as to where the DMT1 and MTP1 are subcellularly co-localized in the BCB, how they function in concert to respond to divalent-metal fluxes on both sides of the BCB, by what mechanism Mn exposure alters the expression and function of both transporters, and how the dysregulation of DMT1 and MTP1 in the BCB by Mn exposure affects brain homeostasis of Fe and Mn, remain mysterious. Thus, to understand the structural functionality of DMT1 and MTP1 in the brain barrier and their dysfunction-associated neuronal disorders, we hypothesize that the altered expression of DMT1 and MTP1 in the choroid plexus following Mn exposure contributes to Mn- induced Fe metabolism disorder in the CSF. Our specific aims are: (1) to explore whether DMT1 and MTP1 control the direction of Fe transport at the BCB by investigating the subcellular location of DMT1 and MTP1 in choroidal epithelia, by blocking or inducing DMT1 and MTP1 expression to determine the direction of Fe and Mn transport at BCB, and by using siRNA technique to silence the genes encoding DMT1 and MTP1 to investigate Fe and Mn uptake and transport kinetics under DMT1 or MTP1 knock-down conditions; (2) to explore whether in vivo chronic Mn exposure distorts the expression of DMT1 and MTP1 in the BCB and selected regional blood-brain barrier and leads to increased fluxes of Fe between the blood and CSF, by using a rat chronic Mn exposure model and by a ventriculo-cisternal perfusion technique; and (3) to explore whether Mn exposure interferes the binding of iron-regulatory proteins to mRNAs of DMT1 and MTP1, since the stem-loop structure exists in 3'-untranslated regions (UTR) and 5'-UTR in DMT1 and MTP1 mRNA, respectively. Studies proposed in this application will define the inter-relationship between DMT1 and MTP1 in the BCB with regard to their subcellular locations, roles in transport of divalent metals at the BCB, and their regulation as affected by Mn exposure; will provide insight into the molecular mechanism by which Mn affects divalent Fe transport by brain barriers; and will ultimately provide a better understanding of Fe dysfunction-related neuronal diseases such as IPD.

描述（由申请人提供）：在特发性帕金森病（IPD）和锰（Mn）诱导的帕金森病中已经显示出改变的脑铁（Fe）稳态。目前的提案延续了我们长期研究目标的中​​心主题，即探索脑屏障系统在金属引起的神经毒性中的作用。二价金属转运蛋白-1 (DMT1) 和金属转运蛋白-1 (MTP1) 是两种新发现的金属转运蛋白，具有跨细胞膜转运金属的功能。在进展报告中，我们证明了血脑脊液 (CSF) 屏障 (BCB) 所在的脉络丛中存在 DMT1 和 MTP1。我们还观察到，Mn 暴露会增加 BCB 上皮细胞中 DMT1 的表达并动员亚细胞 MTP1。然而，以下问题是 DMT1 和 MTP1 在 BCB 中亚细胞共定位的位置、它们如何协同作用以响应 BCB 两侧的二价金属通量、Mn 暴露通过什么机制改变两种转运蛋白的表达和功能，以及 Mn 暴露导致 BCB 中 DMT1 和 MTP1 的失调如何影响脑中 Fe 和 Fe 的稳态 嗯，保持神秘。因此，为了了解脑屏障中 DMT1 和 MTP1 的结构功能及其功能障碍相关的神经元疾病，我们假设锰暴露后脉络丛中 DMT1 和 MTP1 表达的改变导致脑脊液中锰诱导的铁代谢紊乱。我们的具体目标是：（1）通过研究DMT1和MTP1在脉络膜上皮中的亚细胞定位，通过阻断或诱导DMT1和MTP1表达来确定BCB中Fe和Mn转运的方向，并通过使用siRNA技术沉默编码DMT1和 MTP1 用于研究 DMT1 或 MTP1 敲除条件下 Fe 和 Mn 的吸收和运输动力学； (2) 通过使用大鼠慢性锰暴露模型和脑室脑池灌注技术，探讨体内慢性锰暴露是否会扭曲 BCB 和选定区域血脑屏障中 DMT1 和 MTP1 的表达，并导致血液和脑脊液之间 Fe 通量增加； (3)探讨锰暴露是否会干扰铁调节蛋白与DMT1和MTP1 mRNA的结合，因为茎环结构分别存在于DMT1和MTP1 mRNA的3'-非翻译区(UTR)和5'-UTR中。本申请中提出的研究将定义 BCB 中 DMT1 和 MTP1 之间的相互关系，包括它们的亚细胞位置、BCB 中二价金属转运的作用以及它们受 Mn 暴露影响的调节；将深入了解锰影响脑屏障二价铁转运的分子机制；并最终将有助于更好地了解铁功能障碍相关的神经元疾病，例如 IPD。