Effect of morphine on HIV-1 neuroinvasion and brain changes in mice

描述(由申请人提供)：这份R03申请建议对一种新的小鼠HIV-1感染模型进行可行性研究，以直接解决吗啡在促进HIV-1进入大脑和对组织的病毒影响方面的潜在作用。我们发现，正常近交系小鼠可以“自然”感染携带生态亲和性MLV包膜的嵌合HIV-1，称为EcoHIV。对这种感染的动力学研究显示，病毒最初在1周内在外周T细胞和巨噬细胞中突然复制，随后病毒持续在较低水平，诱导抗病毒免疫反应，病毒神经侵袭，以及脑内的一些变化，但在几周的随访中没有其他主要疾病指标。这些特征类似于人类感染HIV-1或猕猴感染SIV的无症状阶段。有趣的是，与全身感染相比，EcoHIV在大脑中的表达和变化是延迟的。这一延迟可能代表了病毒突破血脑屏障(BBB)并建立脑感染所需的时间(和过程)。人类HIV-1介导的脑部疾病也是继发于全身感染，与HIV-1感染的巨噬细胞进入中枢神经系统和神经炎症密切相关。据信，吗啡等滥用药物通过促进艾滋病毒-1或感染细胞通过血脑屏障等途径，加剧了艾滋病毒-1的神经发病。我们相信，EcoHIV-小鼠模型给了我们一个独特的机会，在体内直接实验中解决这一假说的要素。 在这里，我们将尝试回答两个关于吗啡给药与小鼠EcoHIV感染之间可能的功能关系的离散问题：1)吗啡治疗是否促进了EcoHIV感染、神经侵袭和小鼠大脑早期分子变化？我们将使用野生型和Mu阿片受体敲除小鼠，并测定全身性EcoHIV感染的动力学，病毒在脑内的进入和表达，以及脑组织中MCP-1和IL-1β的表达作为脑病理的早期标志；2)吗啡是否增加了EcoHIV感染动物的血脑屏障对大分子和细胞的通透性？在目标1建立的最佳条件下，我们将确定标记白蛋白的摄取和巨噬细胞在小鼠脑内的跨内皮迁移。拟议的项目利用一种新的艾滋病毒-1感染的小动物模型来解决一个关键的公共卫生问题，即滥用药物在加剧艾滋病毒-1感染的后果方面的潜在贡献。这些研究将结合两个实验室在药物滥用研究、艾滋病毒-1生物学、脑研究和动物模型方面的跨学科专业知识，它们将为药物滥用和艾滋病毒-1疾病之间的关系提供新的线索。

DESCRIPTION (provided by applicant): This R03 application proposes feasibility studies in a novel model of HIV-1 infection in mice to address directly the potential role of morphine in facilitating HIV-1 entry into the brain and viral effects on the tissue. We showed that normal inbred mice can be "naturally" infected with a chimeric HIV-1 carrying ecotropic MLV envelope, termed EcoHIV. Kinetic studies of this infection revealed an initial burst of virus replication in peripheral T cells and macrophages within 1 week, followed by virus persistence at lower levels, induction of antiviral immune responses, virus neuroinvasion, and a number of changes in the brain but no other major indicators of disease during several weeks of follow up. These characteristics resemble the asymptomatic stage of HIV-1 infection in humans or SIV infection in macaques. Interestingly, EcoHIV expression and changes in the brain are delayed compared to systemic infection. The delay likely represents the time (and processes) required for the virus to breach the blood brain barrier (BBB) and establish brain infection. The HIV-1-mediated brain disease in people is also secondary to systemic infection and it closely correlates with influx of HIV-1-infected macrophages into the CNS and neuroinflammation. Drugs of abuse such as morphine are believed to exacerbate HIV-1 neuropathogenesis, among others by facilitating transit of HIV-1 or infected cells through the BBB. We believe that the EcoHIV-mouse model gives us a unique opportunity to address elements of this hypothesis in direct experimentation in vivo. Here we will attempt to answer two discrete questions on the possible functional relationship between morphine administration and EcoHIV infection in mice: 1) Does morphine treatment facilitate the course of EcoHIV infection, neuroinvasion, and early molecular changes in mouse brains? We will use wild type and mu opioid receptor knock out mice and determine kinetics of systemic EcoHIV infection, virus entry and expression in the brain, and expression of MCP-1 and IL-1beta in brain tissue as early markers of brain pathology; 2) Does morphine enhance BBB permeability to large molecules and cells in EcoHIV- infected animals? Under optimal conditions established in Aim 1, we will determine uptake of labeled albumin and trans-endothelial migration of macrophages into mouse brain. The proposed project utilizes a novel small animal'model of HIV-1 infection to address a critical public health issue of the potential contribution of drugs of abuse in exacerbating the consequences of HIV-1 infection. The studies will combine interdisciplinary expertise in drug abuse research, HIV-1 biology, brain research, and animal models from two laboratories and they should shed new light on the relationship between drug abuse and HIV-1 disease.