RAMIFIED MICROGLIA AND LENTIVIRUS PERSISTENCE

分支小胶质细胞和慢病毒的持久性

• 批准号: 6188328
• 负责人: DAVID L HUSO
• 金额: $ 18.83万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6188328
• 关键词: AIDS /HIV neuropathy; AIDS dementia complex; Lentivirus; cell cycle; cell line; cerebellum; cytokine receptors; disease /disorder model; fluorescent dye /probe; gene expression; human immunodeficiency virus 1; human tissue; immunocytochemistry; laboratory mouse; latent virus infection; leukocyte activation /transformation; microglia; mixed tissue /cell culture; neural cell adhesion molecules; phenotype; postmortem; provirus; sheep; tissue /cell culture; virus infection mechanism

DESCRIPTION (adapted from applicant's abstract): Neuronal injury and microglial activation are related processes that appear central to a number of chronic neurodegenerative diseases including AIDS dementia. Ramified tissue microglia are highly branched, quiescent cells that secrete neurotrophic factors. Generally, neuronal damage can be an important early trigger in activating ramified tissue microglia to become phagocytic macrophage-like cells. Uncontrolled activation of microglia results in release of a variety of substances that are toxic to bystander neurons. Conversely, healthy neurons and certain soluble factors oppose microglia activation by signaling microglia to maintain a quiescent, ramified phenotype, downregulate production of neurotoxic substances, and upregulate production of neurotrophic factors. Fine regulation of this reversible microglial activation/ramification cycle limits neuronal injury during infection or insult and favors regenerative healing following injury to the CNS. Clearance of cellular reservoirs that harbor HIV during HAART treatment is mainly dependent on the particular turnover rate of the reservoir target cell population. Most of the HIV-1-infected cells in the brain are macrophages and microglia. Ramified tissue microglia in the CNS represent one of the most stable cell types in the body and have one of the slowest turnover rates of any HIV target cell population that has been measured. Virus could persist in these quiescent cells for years or perhaps even decades before the cells turn over. However, since poorly characterized cellular interactions and unknown soluble factors mediate and maintain microglial ramification in the brain and because they are inaccessible, ramified microglia remain poorly understood. The investigators have developed neuron-rich organotypic brain slice cultures and dissociated cortical brain cultures that support microglial ramification and visna lentivirus infection in vitro. This type of system offers a unique opportunity to investigate the biology of the lentivirus-infected ramified microglia in neuron-rich, simulated brain microenvironments conducive to experimental manipulation and mechanistic studies. Such model systems could provide important insights into HIV persistence in the CNS. The central hypothesis is that HIV-infected cells in the brain include ramified tissue microglia with latent or restricted infection. Replication competent provirus persists in this cellular reservoir for prolonged periods in spite of treatment due to the extremely slow turnover rate of these cells and its location behind the blood brain barrier. We will test these hypotheses by: 1) improving and characterizing primary culture models of microglial ramification, 2) determining the effect of lentivirus infection microglial ramification, 3) identifying changes in susceptibility to lentivirus infection that occur during microglial ramification, and 4) characterizing markers and modulators of ramification of infected and uninfected microglia.

描述（改编自申请人摘要）：神经元损伤和小胶质细胞 激活是相关的过程，似乎是许多慢性疾病的核心。 神经退行性疾病，包括艾滋病痴呆症。分支组织小胶质细胞 是高度分支的静止细胞，分泌神经营养因子。 一般来说，神经元损伤可能是激活的重要早期触发因素， 分支组织小胶质细胞成为吞噬巨噬细胞样细胞。 小胶质细胞的不受控制的激活导致释放多种 对旁观者神经元有毒的物质。相反，健康的神经元和 某些可溶性因子通过向小胶质细胞发出信号来对抗小胶质细胞活化， 维持静止的分枝表型，下调神经毒素的产生 物质，并上调神经营养因子的产生。精细调节 这种可逆的小胶质细胞激活/分支循环限制了神经元的 在感染或损伤期间的损伤，并有利于再生愈合后， 损伤CNS。 在HAART治疗过程中清除携带HIV的细胞库， 主要取决于储库靶细胞的特定周转率 人口大脑中大多数感染HIV-1的细胞是巨噬细胞， 小胶质细胞中枢神经系统中的分支组织小胶质细胞代表了中枢神经系统中 稳定的细胞类型在体内，并有一个最慢的周转率的任何 已测量的HIV靶细胞群。病毒可以在这些 静止细胞数年甚至数十年，然后细胞才开始转变。 然而，由于细胞间相互作用的特征不明显， 因子介导和维持大脑中的小胶质细胞分支， 它们是不可接近的，分支的小胶质细胞仍然知之甚少。的 研究者已经开发出富含神经元的器官型脑切片培养物， 支持小胶质细胞分支的分离的皮质脑培养物， visna慢病毒体外感染。这种类型的系统提供了一个独特的 有机会研究慢病毒感染的分枝 在富含神经元的模拟大脑微环境中的小胶质细胞， 实验操作和机械研究。这种模型系统可以 提供了重要的见解艾滋病毒在中枢神经系统的持久性。 核心假设是，大脑中感染艾滋病毒的细胞包括分支的 组织小胶质细胞具有潜伏性或限制性感染。复制能力的 前病毒在细胞中存留很长时间， 由于这些细胞的周转速度非常慢， 位于血脑屏障后面。我们将通过以下方式检验这些假设：1） 改进和表征小胶质细胞衍生物的原代培养模型， 2)确定慢病毒感染小胶质细胞衍生物的影响，3） 确定在慢病毒感染期间发生的对慢病毒感染的易感性的变化， 小胶质细胞衍生物，和4）表征小胶质细胞衍生物的标记物和调节剂， 感染和未感染的小胶质细胞的分支。