RAMIFIED MICROGLIA AND LENTIVIRUS PERSISTENCE

描述(摘自申请者摘要)：神经元损伤和小胶质细胞 激活是相关过程，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 是高度分枝的静止细胞，分泌神经营养因子。 一般来说，神经元损伤可能是激活的一个重要的早期触发因素。 使组织小胶质细胞分枝，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各种不同的 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送信号来抑制小胶质细胞的激活 保持静止的、分叉的表型，下调神经毒素的产生 物质，并上调神经营养因子的产生。精细监管 这一可逆的小胶质细胞激活/分支循环限制了神经元 在感染或侮辱过程中受伤，并有利于再生愈合 中枢神经系统受伤。 在HAART治疗期间清除携带艾滋病毒的细胞储存库 主要取决于油藏目标单元的特定周转率 人口。大脑中大多数感染HIV-1的细胞是巨噬细胞和 小胶质细胞。中枢神经系统中的分支组织小胶质细胞是最常见的 体内细胞类型稳定，周转率是最慢的 已测量的HIV目标细胞数量。病毒可能会在这些地方持续存在 在细胞翻转之前，细胞会静止数年甚至数十年。 然而，由于表征不佳的细胞相互作用和未知的可溶物 调节和维持大脑中小胶质细胞分支的因素，因为 它们是不可接近的，分支的小胶质细胞仍然鲜为人知。这个 研究人员已经开发出富含神经元的器官型脑片培养物和 分离的皮质脑培养物支持小胶质细胞分支和 Visna慢病毒的体外感染。这种类型的系统提供了独特的 研究感染慢病毒的分枝病毒生物学的机会 富含神经元的模拟脑微环境中的小胶质细胞有助于 实验操作和机械研究。这样的模型系统可以 提供有关艾滋病毒在中枢神经系统中持续存在的重要见解。 中心假设是大脑中感染艾滋病毒的细胞包括分支细胞 潜伏感染或局限性感染的组织小胶质细胞。具备复制能力 前病毒在这个细胞储存库中持续了很长时间，尽管 由于这些细胞的周转率极低而导致的治疗 血脑屏障后面的位置。我们将通过以下方式检验这些假设：1) 小胶质细胞分枝原代培养模型的改进与鉴定， 2)确定慢病毒感染对小胶质细胞分支的影响；3) 确定慢病毒感染易感性的变化发生在 小胶质细胞的分支，以及4)表征的标志物和调节物 感染和未感染的小胶质细胞的分支。

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.