HIV interaction with drugs of abuse and adult neurogenesis

描述(申请人提供)：这是一个R21申请，以回应PAR-09-222题为“尖端基础研究奖(CEBRA)”。这一第一阶段CEBRA应用的主要目标是创建和表征一种新的小鼠模型，用于研究艾滋病毒感染和药物滥用对成人神经发生的联合影响。在整个成年期，在侧脑室的脑室下区和齿状回的颗粒下区(DG)都有活跃的神经发生；后者在海马区产生颗粒细胞，这与神经认知功能有关，并受到药物滥用和艾滋病毒感染等病理刺激的负面调节。众所周知，包括鸦片类药物、可卡因和甲基苯丙胺(冰毒)在内的滥用药物会抑制成人神经发生。相比之下，人们对艾滋病毒感染对成人神经发生的影响、负责的病毒决定因素以及潜在的细胞和分子机制知之甚少。此外，关于艾滋病毒感染和药物滥用对成人神经发生的联合影响的信息很少。我们最近建立了多西环素(Dox)诱导的脑特异性hiv-1tat双基因小鼠模型，在该模型中，tat的表达可以被诱导为仅在脑中表达，并且我们已经证明，在没有hiv-1感染的情况下，脑中tat蛋白的表达足以诱导神经行为和神经病理，概括了hiv-1感染者大脑中的一些重要特征(Kim等，Am)。J.Path，162：1693-707,2003)。我们的研究表明，TAT对成人神经发生具有潜在的抑制作用。该项目的总体假设是，艾滋病毒TAT与滥用药物相互作用，导致感染艾滋病毒的成年人神经再生减少，并导致这些人的神经认知功能障碍。为了验证这一假设，在这个第一阶段的CEBRA方案中，我们建议通过用Nestin-GFP转基因小鼠培育ITAT双基因小鼠来建立可诱导的脑特异性TAT/神经前体细胞(NPC)特异性Nestin启动子驱动的GFP小鼠模型(ITAT/Nestin-GFP)。在这个新的模型中，直接、方便和可重现的鼻咽癌可视化和跟踪将为我们提供一个独特的机会，通过表征暴露于冰毒和表达TAT的ITAT/Nestin-GFP小鼠中鼻咽癌的时空分布、分化和存活，为我们研究TAT效应和TAT/METH联合对成年神经发生的影响提供了独特的机会；其功能后果将与这些小鼠的神经认知功能相关。完成这些研究将使我们能够确定第二阶段TAT/甲基改变的神经发生的细胞和分子机制，我们相信这将最终有助于确定治疗方法(分子)，这些方法(分子)将促进新生的神经发生，以功能替代HIV介导的神经退化，并预防、改善或逆转HIV感染者和HIV感染吸毒者的HIV相关性痴呆或轻度认知和运动障碍的并发症。 与公共卫生的相关性：艾滋病毒/艾滋病的流行在21世纪构成了巨大的社会、经济和政治挑战。截至2008年12月，全世界估计有3400万成人和210万儿童感染了艾滋病毒。HIV对大脑的感染发生在感染过程的早期，通常会导致认知、运动和其他行为问题。在高效抗逆转录病毒治疗的时代，一种较轻微的艾滋病毒相关痴呆症，即所谓的轻微认知和运动障碍，在艾滋病毒感染人群中变得普遍和普遍。虽然我们对疾病机制的了解仍然不完全，但目前还没有有效的治疗方法来减少、预防或逆转艾滋病毒介导的认知、运动和行为问题。另一方面，艾滋病毒感染和药物滥用是世界各地相互关联的流行病，而两者本身都能够导致认知缺陷。在这项研究中，我们建议建立一种新的小鼠模型，用于研究艾滋病毒感染、药物滥用和认知功能障碍之间的联系。这一模式最终将导致制定治疗策略，以恢复艾滋病毒感染者和艾滋病毒感染者的正常认知功能。

DESCRIPTION (provided by applicant): This is a R21 application in response to PAR-09-222 entitled "Cutting-Edge Basic Research Award (CEBRA)". The main goal of this Phase I CEBRA application is to create and characterize a novel mouse model for studies on the combined impact of HIV infection and drug abuse on adult neurogenesis. Active neurogenesis continues throughout adulthood in both the subventricular zone of the lateral ventricle and the subgranular zone of the dentate gyrus (DG); the latter gives rise to granule cells in the hippocampus, which has been linked to neurocognitive function and is negatively regulated by pathological stimuli such as drug abuse and HIV infection. It is well established that drugs of abuse including opiates, cocaine, and methamphetamine (METH) inhibit adult neurogenesis. In contrast, not much is known about the effects of HIV infection on adult neurogenesis, the responsible viral determinants and the underlying cellular and molecular mechanisms. Furthermore, there is scant information about the combined impact of HIV infection and drug abuse on adult neurogenesis. We have recently established an doxycycline (Dox)-inducible brain-specific HIV-1 Tat bigenic mouse model (iTat) in which Tat expression can be induced to exclusively express in the brain, and we have demonstrated that expression of Tat protein in the brain in the absence of HIV-1 infection is sufficient to induce neurobehavioral and neuropathologies that recapitulate some important features in the brain of HIV-1-infected individuals (Kim et al., Am. J. Path, 162:1693-707, 2003). Our studies suggest a potential inhibitory role of Tat on adult neurogenesis. The overall hypothesis of this project is that HIV Tat interacts with drugs of abuse, leading to decreased neurogenesis in HIV-infected adults and contributing to the neurocognitive dysfunction in these individuals. To test this hypothesis, in this Phase I CEBRA proposal, we propose to create an inducible brain-specific Tat/neuron progenitor cells (NPC)-specific nestin promoter-driven GFP mouse model (iTat/nestin-GFP) by breeding the iTat bigenic mice with nestin-GFP transgenic mice. Direct, convenient and reproducible visualization and tracking of NPC in this new model will provide a unique opportunity for us to study Tat effects and Tat/METH combined effects on adult neurogenesis through characterization of the temporal and spatial distribution, differentiation and survival of NPC in METH-exposed and Tat-expressing iTat/nestin-GFP mice; the functional consequences will be correlated with the neurocognitive function of these mice. Completing the studies will allow us to define the cellular and molecular mechanisms responsible for Tat/METH-altered neurogenesis at Phase II, which we believe will eventually help identify therapeutic approaches (molecules) that promote de novo neurogenesis for functional replacement of HIV-mediated neurodegeneration and prevent, ameliorate, or reverse the complications of HIV- associated dementia or mild cognitive and motor disorders of HIV-infected individuals and HIV-infected drug abusers. PUBLIC HEALTH RELEVANCE: The HIV/AIDS epidemic has posed a great social, economic and political challenge in the 21st century. As of December 2008, 34.0 million adults and 2.1 million children are estimated to have acquired HIV infection worldwide. HIV infection of the brain occurs early in the course of infection and often leads to cognitive, motor, and other behavioral problems. In the era of highly active antiretroviral therapy, a milder form of HIV-associated dementia so-called minor cognitive and motor disorder has become predominant and prevalent among the HIV-infected population. While our understanding of the disease mechanisms remains incomplete, there are no effective therapies to reduce, prevent, or reverse HIV-mediated cognitive, motor and behavioral problems at the present time. On the other hand, HIV infection and drug abuse are interlinked epidemics throughout the world, while each alone is capable of causing cognitive deficits. In this current study, we propose to create a novel mouse model for studies on the connection between HIV infection, drug abuse and cognitive dysfunction. This model shall eventually lead to development of therapeutic strategies to restore the normal cognitive function of HIV-infected individuals and HIV-infected drug abusers.