Molecular basis of neuronal dysfunction in AIDS

艾滋病神经元功能障碍的分子基础

• 批准号: 6863758
• 负责人: Francesca Peruzzi
• 金额: $ 26.34万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-02 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6863758
• 关键词: AIDS; AIDS /HIV neuropathy; AIDS dementia complex; DNA footprinting; apoptosis; cellular pathology; clinical research; flow cytometry; gene expression; gene induction /repression; green fluorescent proteins; human immunodeficiency virus 1; immunoprecipitation; laboratory rat; molecular pathology; neurons; polymerase chain reaction; protein structure; terminal nick end labeling; tissue /cell culture; transcription factor

DESCRIPTION (provided by applicant): HIV-1 invasion of the Central Nervous System, CNS, induces a variety of clinical abnormalities including dementia, also known as HIV-1 associated dementia, HAD. Histologically, brain biopsy from AIDS patients with neurological disorders exhibit a broad ranges of abnormalities, most notably neuronal cell loss. The absence of neuronal infection suggested an indirect role for the virus to induce neuronal cell damages. Results from a large number of studies indicated that expression and secretion of several cellular proteins including cytokines and immunomodulators from the infected macrophages, microglia, and astrocytes in the brain participate in the neuronal cell damages. In addition to cellular factors, the viral regulatory protein Tat has received attention due to its unique ability to be secreted by the infected cells, enter into uninfected cells and alter the expression of cellular genes in the absence of viral infection. Moreover, Tat protein has been shown to have neurotoxic activity, most likely through dysregulating signaling pathways that are critical for neuronal cell survival. By using PC12 neuronal cell model, as well as primary rat neuronal cells, we demonstrated that Tat stimulate the expression of Id gene, a known cellular protein that inhibits differentiation of neuronal cells. Id, by affecting expression and activity of several factors which control the cell cycle promotes unscheduled entering of quiescent cells into proliferating stage and that results in suppression of a group of proteins that are implicated in the maintenance of differentiated cells. The basic helix-loop-helix, bHLH, family of DNA binding proteins such as Ngn, NeuroD, and Mash1, are the primary targets for Id1 which upon dysregulation may promote neuronal cell injury and apoptosis. Our preliminary data suggest that activation of Id1 gene by Tat is mediated via a novel regulatory pathway that includes critical transcription factors such as Egr1, C/EBP and SP1, all of which physically and functionally interact with Tat. In Aim one of this project we will perform a series of comprehensive functional and structural studies to unravel the molecular mechanisms involved in activation of Id1 by Tat in neuronal cells. In Aim two, we will investigate the importance of Id1, whose expression is elevated by Tat, in neuronal cell cycle, control of expression and activity of factors controlling cell entry into cell cycle and checkpoints such as p21, p16, pRb, and various cyclins. Furthermore, the role of Tat-induced overproduction of Id1 on the expression and activity of bHLH will be assessed. The outcome of these studies will provide a new information on the pathways which are affected by HIV-1 Tat, and will assist to improve our effort for developing strategies against HIV-1 induced neuronal cell injury.

描述(申请人提供)：HIV-1入侵中枢神经系统，导致多种临床异常，包括痴呆症，也称为HIV-1相关性痴呆症。组织学上，患有神经系统疾病的艾滋病患者的脑活检显示出广泛的异常，最明显的是神经细胞丢失。没有神经细胞感染表明病毒在诱导神经细胞损伤方面起到了间接作用。大量研究结果表明，脑内感染的巨噬细胞、小胶质细胞和星形胶质细胞等多种细胞蛋白的表达和分泌参与了神经细胞的损伤。除了细胞因子外，病毒调节蛋白TAT因其独特的能力而受到关注，它可以由感染细胞分泌，进入未感染的细胞，并在没有病毒感染的情况下改变细胞基因的表达。此外，TAT蛋白已被证明具有神经毒性活性，很可能是通过对神经细胞生存至关重要的信号通路失调来实现的。通过使用PC12神经细胞模型和原代培养的大鼠神经细胞，我们证明了TAT刺激ID基因的表达，ID基因是一种已知的抑制神经细胞分化的细胞蛋白。通过影响几个控制细胞周期的因子的表达和活性，促进静止期细胞进入增殖期，导致一组与分化细胞维持有关的蛋白质被抑制。碱性螺旋-环-螺旋(BHLH)是DNA结合蛋白家族，如NGN、NeuroD和Mash1，是Id1的主要靶点，一旦失调，可能会促进神经细胞的损伤和凋亡。我们的初步数据表明，TAT激活Id1基因是通过一种新的调控途径来实现的，其中包括Egr1、C/EBP和SP1等关键转录因子，所有这些转录因子都与TAT在物理和功能上相互作用。作为该项目的目标之一，我们将进行一系列全面的功能和结构研究，以揭示TAT在神经细胞中激活Id1的分子机制。在第二个目标中，我们将研究Id1在神经细胞周期中的重要性，它的表达被TAT上调，控制控制细胞进入细胞周期的因子的表达和活性，以及p21、p16、pRb和各种周期蛋白。此外，还将评估TAT诱导的Id1过度生产对bHLH表达和活性的影响。这些研究的结果将提供关于HIV-1 TAT影响途径的新信息，并将有助于我们努力制定应对HIV-1诱导的神经细胞损伤的策略。