Neurotrophic factors and HIV-mediated neuronal injury

神经营养因子和 HIV 介导的神经元损伤

• 批准号: 6893180
• 负责人: Italo Mocchetti
• 金额: $ 35.07万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6893180
• 关键词: AIDS dementia complex; HIV envelope protein gp120; NMDA receptors; RNase protection assay; apoptosis; brain derived neurotrophic factor; chemokine receptor; confocal scanning microscopy; cysteine endopeptidases; enzyme linked immunosorbent assay; granule cell; hippocampus; human immunodeficiency virus 1; immunocytochemistry; laboratory mouse; laboratory rat; magnetic resonance imaging; nerve injury; neural degeneration; neural plasticity; neurotoxicology; receptor expression; western blottings

DESCRIPTION (provided by applicant): Patients with the human immunodeficiency virus type 1 (HIV-1) develop in the late phase of infection a complex of neurological signs termed Acquired Immune Deficiency Syndrome-related Dementia (AIDSD). These patients exhibit a broad spectrum of motor impairments and cognitive deficits, which follow or parallel cellular loss, atrophy and morphological changes in their brains. The viral envelope glycoprotein gp120 has been suggested to be one of the causal agents of neuronal loss observed in these patients. However, little is known about the molecular and cellular mechanism(s) of the neurotoxic effect of gp120. Data from a previous proposal have established that gp120 causes neuronal cell death by activating an apoptotic pathway through the chemokine receptor CXCR4. Interestingly, the neurotrophin brain-derived neurotrophic factor (BDNF) prevents gp120-mediated neurotoxicity in vitro by decreasing CXCR4 levels. These data lead to the overall hypothesis that BDNF may reduce gp120 toxicity also in vivo. We propose to study the molecular and cellular mechanisms whereby BDNF blocks gp120 neurotoxicity and the involvement of CXCR4. In particular, we plan to examine the role of CXCR4 in gp120-mediated toxicity in vivo by injecting gp120IIIB into the lateral ventricle of rats and comparing its toxic activity with that of gpBal, a strain of gp120 that binds to the chemokine receptor CCR5. We propose to analyze apoptosis by immunohistochemical and biochemical assessment of activated caspase-3 and caspase-9, two proteases that play a crucial role in the apoptotic pathway. These studies will be accompanied by experiments aimed at establishing the molecular and cellular mechanisms whereby BDNF regulates CXCR4 expression. We propose to use BDNF heterozygous (+/-) mice and cerebellar granule cells in culture. In these studies, we will test the hypothesis that BDNF is neuroprotective against gp120 because of its ability to reduce the expression of CXCR4 or increase its internalization. CXCR4 expression will be determined by histological and biochemical detection of CXCR4 immunoreactivity and mRNA, and CXCR4 internalization will be monitored by quantifying beta-arrestin- mediated endocytosis. Moreover, we propose to establish whether BDNF, infused in the lateral ventricle or by recombinant adeno-associated virus, impairs the ability of gp120 to induce apoptosis. Overall, the results of the present study 1) will provide a major break-through on the mechanisms whereby gp120 causes neuronal cell death and the related morphological alterations that may account for the motor and cognitive deficits found in human AIDSD, and 2) will explore the significance of endogenous and exogenous BDNF in the development of a new therapeutic approach for HIV-1-related neurodegenerative diseases.

描述（由申请人提供）：患有人类免疫缺陷病毒1型（HIV-1）的患者在感染的后期发展出一种称为获得性免疫缺陷综合征相关痴呆症（AIDSD）的神经系统症状的复合物。这些患者表现出广泛的运动障碍和认知缺陷，这些缺陷伴随着或平行的细胞丧失，大脑的萎缩和形态变化。已经认为病毒包膜GP120是这些患者观察到的神经元丧失的因果因子之一。然而，对GP120神经毒性作用的分子和细胞机制知之甚少。先前提案的数据确定，GP120通过激活通过趋化因子受体CXCR4的凋亡途径来引起神经元细胞死亡。有趣的是，神经营养蛋白脑源性的神经营养因子（BDNF）通过降低CXCR4水平来防止GP120介导的神经毒性。这些数据导致了总体假设，即BDNF可能在体内降低GP120的毒性。我们建议研究BDNF阻断GP120神经毒性和CXCR4参与的分子和细胞机制。特别是，我们计划通过将GP120IIIB注射到大鼠外侧心室中，并将其毒性活性与GPBAL的毒性活性进行比较，该菌株是GP120的GP120菌株，该毒性活性通过将GP120IIIB注射到GP120介导的体内毒性中，该毒性与趋化因子受体CCR5结合。我们建议通过对活化的caspase-3和caspase-9进行免疫组织化学和生化评估来分析凋亡，这两种蛋白酶在凋亡途径中起着至关重要的作用。这些研究将伴随着旨在建立分子和细胞机制的实验，BDNF调节CXCR4表达。我们建议在培养中使用BDNF杂合（+/-）小鼠和小脑颗粒细胞。在这些研究中，我们将检验以下假设：BDNF对GP120具有神经保护作用，因为它具有降低CXCR4表达或增加其内在化的能力。 CXCR4表达将由CXCR4免疫反应性和mRNA的组织学和生化检测确定，并且CXCR4内部化将通过量化β-art甲介导的内吞作用来监测。此外，我们建议确定BDNF是在侧心室中注入还是通过重组腺相关病毒损害GP120诱导凋亡的能力。总体而言，本研究的结果1）将为GP120引起神经元细胞死亡和相关形态变化的机制提供重大突破，这可能解释了人类AIDSD中的运动和认知缺陷，而2）将探索在Newurease neureder neureder neureder的开发中，探索BDNF的意义。