Markers of HIV Brain Disease under HAART: Validation in a Mouse Model

描述（由申请人提供）：本提案是针对PA-07-089提交的。尽管在恢复艾滋病毒1型感染者的免疫功能和认知功能方面取得了总体成功，但高活性抗逆转录病毒疗法对日益普遍的轻度中枢神经系统疾病的影响有限。基于我们的研究结果，轻度认知和运动障碍（MCMD）患者的大脑中存在治疗独立的、显著的基因失调，我们假设，通过现有的治疗方法持续存在的长期感染细胞引起的脑生理学核心变化，这些治疗方法不是为了阻止整合前病毒的表达而设计的。这些细胞不断产生的病毒蛋白会引起累积的炎症、抗病毒和氧化应激反应，从而影响神经元的功能。为了验证这一假设以及核心缺陷背后的一种机制，我们提出了四个具体目标：1)建立代表轻度HIV CNS疾病患者的全基因组脑基因表达谱；2)在接受抗逆转录病毒治疗的情况下，确定持续轻度HIV中枢神经系统疾病的生物学途径和大脑特征中的生物标志物；3)在免疫正常和免疫缺陷小鼠HIV感染模型中验证选定的轻度HIV CNS疾病标记物；4)验证轻度、慢性HIV中枢神经系统疾病依赖于不受现有抗逆转录病毒治疗影响的低水平病毒转录的假设。我们依靠S. Morgello博士收集的定义明确的患者队列的脑组织，通过基因组宽表达分析和生物信息学发现的基因，Haughey博士的确认性研究，包括脂质代谢物中可见的氧化应激途径，以及复制轻度中枢神经系统疾病许多特征的小鼠HIV感染的强大实验模型。使用可以感染小鼠并可进行基因修饰的嵌合HIV，我们将测试轻度中枢神经系统疾病的一个因果假设：尽管有效治疗，大脑中持续存在的低水平病毒转录维持了以MCMD表达的脑细胞生理学失调。如果这些研究表明，尽管抗病毒治疗，低水平的HIV-1表达仍会损害大脑的细胞功能，那么应该努力开发新的抗病毒药物来阻断细胞储存库的病毒转录。医学通过开发有效的抗病毒药物，延长了艾滋病毒感染者的寿命，改善了他们的健康状况。然而，尽管进行了治疗，HIV疾病的某些方面仍然存在，其中之一导致大脑和中枢神经系统的功能异常。我们建议使用最先进的基因发现和脂质代谢组学工具来确定这种轻微但显著且持续的脑部疾病的分子基础。一旦在人类身上得到证实，我们将使用这些轻度脑部疾病的标记物来测试由HIV感染引起的类似疾病是否在药物治疗的情况下持续存在，即使病毒感染开始在大脑中。最后，我们将通过有效的治疗，在小鼠大脑中建立一种实验性的HIV感染，直到它被激活，我们将对HIV感染者轻度脑部疾病的起源提出疑问。通过开启和关闭这种大脑HIV，我们将确定是否是残留的HIV表达本身导致了大脑中现有药物无法控制的轻微疾病。这项研究可能会对控制目前HAART疗法下持续存在的HIV中枢神经系统损伤提出两项建议：a)相对于目前的惯例，更早地进行血清转化的抗病毒干预；b)呼吁科学界和药学界开发能够阻止HIV表达的抗HIV药物。

DESCRIPTION (provided by applicant): This proposal is submitted in response to PA-07-089. Despite its overall success at restoring immune function and often cognitive function in demented HIV-1-infected persons, highly active antiretroviral therapy has limited effects upon milder CNS disease that is increasingly prevalent. Based on our findings of treatment independent, significant gene dysregulation in brains of patients with minor cognitive and motor disorder (MCMD), we hypothesize that there are core changes in brain physiology arising from long-lived infected cells that persist through existing therapies, which were not designed to arrest expression of integrated provirus. Unabated production of viral proteins by these cells can cause cumulative inflammatory, antiviral, and oxidative stress reactions that affect neuronal function. To test this hypothesis as well as one mechanism underlying the core defect we propose four Specific Aims to: 1) establish genome-wide brain gene expression profiles representative of patients with milder forms of HIV CNS disease; 2) identify biological pathways and biomarkers in the brain characteristic of continuing mild HIV CNS disease in the presence of antiretroviral treatment; 3) validate selected markers of mild HIV CNS disease in a mouse model of HIV infection in immunocompetent and immunodeficient mice; 4) test the hypothesis that mild, chronic HIV CNS disease depends upon low level virus transcription unaffected by existing antiretroviral treatment. We rely upon brain tissue from well defined patient cohorts assembled by Dr. S. Morgello, gene discovery through genome wide expression analysis and bioinformatics, confirmatory studies including pathways of oxidative stress visible in lipid metabolites with Dr. Haughey, and a robust experimental model of HIV infection in mice that reproduces many features of mild CNS disease. Using chimeric HIV that can infect mice and is amenable to genetic modification, we shall test one causal hypothesis for mild CNS disease: low-level virus transcription that persists in the brain despite effective therapy maintains dysregulation of brain cell physiology that is expressed as MCMD. If these studies demonstrate that low level HIV-1 expression impairs cellular function in the brain despite antiviral treatment, efforts should be directed toward development of new antiviral agents to block viral transcription from cellular reservoirs. PUBLIC HEALTH RELEVANCE Medical science has prolonged life and improved health of HIV-infected people through development of effective antiviral drugs. Nevertheless, some aspects of HIV disease persist despite treatment, one of these leads to functional abnormalities in the brain and central nervous system. We propose to determine the molecular bases of this mild, but significant and persistent brain disease using state-of-the-art gene discovery and lipid metabolomics tools. Once confirmed in human beings, we shall use these markers of mild brain disease to test whether a similar disease caused by HIV infection of mice persists in the presence of drug treatment, even when the virus infection begins in the brain. Finally, we shall ask questions about the origin of mild brain disease in HIV infected people with effective therapy by establishing an experimental HIV infection in the brains of mice that is silent until it is turned on. By turning on and off this brain HIV, we shall determine whether it is residual HIV expression itself that causes the mild disease in the brain that cannot be controlled by existing drugs. This research may lead to two recommendations for control of the HIV CNS impairment that persists under current HAART regimes: a) earlier antiviral intervention relative to seroconversion than it is customary today; b) a call to the scientific and pharmaceutical communities to develop anti-HIV drugs that stop HIV expression.