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

描述（由申请人提供）：本R03申请提出了在小鼠HIV-1感染的新模型中进行可行性研究，以直接解决吗啡在促进HIV-1进入大脑和病毒对组织的影响中的潜在作用。我们发现正常的近亲繁殖小鼠可以“自然”感染嵌合HIV-1携带亲生态MLV包膜，称为EcoHIV。这种感染的动力学研究显示，在1周内，病毒在周围T细胞和巨噬细胞中复制的初始爆发，随后病毒在较低水平持续存在，诱导抗病毒免疫反应，病毒神经侵入，在几周的随访中，大脑发生了许多变化，但没有其他主要疾病指标。这些特征类似于人类HIV-1感染或猕猴SIV感染的无症状阶段。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。这种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，它与hiv -1感染的巨噬细胞流入中枢神经系统和神经炎症密切相关。滥用药物如吗啡被认为会加剧HIV-1的神经发病机制，其中包括促进HIV-1或受感染细胞通过血脑屏障的转运。我们相信，ecohiv小鼠模型为我们提供了一个独特的机会，可以在体内直接实验中解决这一假设的要素。

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.