Nef and neuroAIDS: role of cholesterol metabolism impairment and inflammation

Nef 和神经艾滋病：胆固醇代谢障碍和炎症的作用

基本信息

批准号：
9352556
负责人：
MICHAEL Ilya BUKRINSKY
金额：
$ 20万
依托单位：
GEORGE WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2020-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9352556
关键词：
AIDS Dementia Complex ATP binding cassette transporter 1 Acute Affect Anti-HIV Agents Anti-Retroviral Agents Astrocytes Atherosclerosis Autopsy Basic Science Bioinformatics Blood Brain Cells Characteristics Cholesterol Cholesterol Homeostasis Chronic Collaborations Comorbidity Complement Data Defect Demyelinations Disease Down-Regulation Encephalitis Endothelial Cells Epigenetic Process Gene Expression Goals HIV HIV Envelope Protein gp120 HIV Infections HIV-1 HIV-associated neurocognitive disorder Hepatocyte Impaired cognition Impairment In Vitro Incidence Inflammation Inflammatory Inflammatory Response Laboratories Mediating Memory Metabolic Microglia Modification Molecular Myeloid Cells Nerve Degeneration Neurocognitive Neurocognitive Deficit Neuroglia Neurologic Neurons Neuropathogenesis Oligodendroglia Pathogenesis Pathogenicity Pathologic Patients Phenotype Property Proteins Publishing Quality of life Recombinants Recording of previous events Research Personnel Role Sampling Severities Site Slice Stimulus Stream Testing Therapeutic Viral Load result Viral Proteins Virion Virulence Factors base cholesterol transporters cognitive function effective therapy functional disability in vivo innovation macrophage monocyte myelination nef Protein nervous system disorder neuroAIDS neuroinflammation neuron loss neurotoxic novel prevent protein protein interaction remyelination screening therapeutic development translational impact virtual

项目摘要

NeuroAIDS is an HIV infection-associated neurological comorbidity that significantly affects life quality of infected subjects. Introduction of combination anti-retroviral therapy (cART) has markedly reduced the incidence of HIV-associated dementia (HAD), a severe form of neuroAIDS, but cognitive impairment remains prevalent even in subjects with undetectable viral load. The mild forms of neuroAIDS are not associated with neurodegeneration or severe inflammation, but are characterized by neuronal demyelination and functional impairment. Therefore, pathogenic mechanisms responsible for the neurologic comorbidities in the cART era are different from those previously implicated in HAD. In this application, we propose a novel mechanism for pathogenesis of cognitive dysfunction in HIV-infected subjects: we hypothesize that Nef induces CNS demyelination by impairing cholesterol metabolism in glial cells and promoting pro-inflammatory status of brain macrophages. Studies from our group demonstrated Nef-induced inhibition of cholesterol efflux and characterized the mechanism of this effect, which involves downregulation and inactivation of the main cellular cholesterol transporter ABCA1. Importantly, ABCA1 downregulation occurs not only in HIV-infected cells, but also in bystander cells affected by Nef released from infected cells. Given that microglial cells and astrocytes in the brain are a recognized HIV reservoir that may produce Nef even under successful cART therapy, it is likely that ABCA1 in astrocytes and oligodendrocytes is also affected by Nef. This may be the reason for persistence of cognitive impairment despite cART, even in subjects with undetectable viral load. Our preliminary results show that treatment of brain slices with recombinant Nef induces demyelination. The mechanisms behind the Nef effects on astrocytes and oligodendrocytes will be investigated in Aim 1 of the proposal. The bioinformatics and protein interaction studies in this aim will be performed in the laboratory of our Russian partners, who are experts in neurological disorders and with whom we have established a long-standing productive collaboration in studies of Nef-induced impairment of ABCA1. Aim 2 will be devoted to studies of Nef's contribution to persistent neuroinflammation characteristic to HIV infection. Our preliminary results suggest that Nef induces pro-inflammatory memory in differentiating monocytes, leading to hyperresponsiveness of these cells to inflammatory stimuli. Together with our Russian collaborators, we will extend these findings to brain macrophages and will characterize gene expression and epigenetic changes induced by Nef. In Aim 3, we will perform screening for compounds targeting the pathogenic effect of Nef on cholesterol metabolism and inflammation. Our Russian collaborators will carry out this screening, and testing of identified compounds in vitro and in vivo will be performed at both sites. These studies will provide a comprehensive phenotypical and mechanistic characterization of the important pathogenic activity of HIV Nef, and will identify new anti-HIV agents that may be developed to treat HIV-associated neurocognitive disease.

神经辅助是一种与HIV感染相关的神经系统合并症，对生命质量显着影响感染受试者。引入抗逆转录病毒疗法（CART）的引入显着降低了艾滋病毒相关痴呆（HAD）的发病率是一种严重的神经辅助形式，但认知障碍仍然存在即使在患有无法检测的病毒负荷的受试者中也普遍存在。轻度的神经助剂形式与神经变性或严重的炎症，但具有神经元脱髓鞘和功能的特征损害。因此，导致推车时代神经系统合并症的致病机制与以前涉及的HET的人不同。在此应用中，我们提出了一种新的机制 HIV感染受试者认知功能障碍的发病机理：我们假设NEF诱导CNS 通过损害神经胶质细胞中的胆固醇代谢并促进大脑的促炎状态而脱髓鞘巨噬细胞。我们小组的研究表明，NEF诱导的胆固醇外排抑制和表征了这种作用的机制，涉及主要细胞的下调和失活胆固醇转运蛋白ABCA1。重要的是，ABCA1下调不仅发生在HIV感染的细胞中，还会发生在受感染细胞释放的NEF影响的旁观细胞中。考虑到小胶质细胞和星形胶质细胞大脑是公认的艾滋病毒水库，即使在成功的购物车治疗下，也可能会产生NEF 星形胶质细胞和少突胶质细胞中的ABCA1也受NEF的影响。这可能是坚持不懈的原因尽管卡车，但即使在患有无法检测的病毒载荷的受试者中，认知障碍也是如此。我们的初步结果证明用重组NEF处理脑切片会诱导脱髓鞘。背后的机制 NEF对星形胶质细胞和少突胶质细胞的影响将在该提案的AIM 1中进行研究。生物信息学在我们的俄罗斯合作伙伴的实验室中将进行此目标的蛋白质相互作用研究神经系统疾病的专家以及我们与之建立了长期富有成效的合作在NEF诱导的ABCA1损伤的研究中。 AIM 2将专门研究NEF对 HIV感染的持续性神经炎症特征。我们的初步结果表明NEF诱导分化单核细胞中的促炎记忆，导致这些细胞的过度反应到炎症刺激。与我们的俄罗斯合作者一起，我们将把这些发现扩展到大脑巨噬细胞并将表征NEF诱导的基因表达和表观遗传变化。在AIM 3中，我们将对靶向NEF对胆固醇代谢的致病作用的化合物进行筛查炎。我们的俄罗斯合作者将进行此次筛选，并在体内和体内都将在两个地点进行。这些研究将提供全面的表型和 HIV NEF重要的致病活性的机械表征，将识别新的抗HIV 可以开发以治疗与HIV相关的神经认知疾病的药物。