Cortical pathophysiology in cocaine sef-administering HIV-1 transgenic rats

描述（由申请人提供）： 可卡因滥用，艾滋病毒+个人经历更严重和迅速发展的神经精神障碍和艾滋病毒相关的神经认知障碍（手）比非滥用艾滋病毒+个人。这些疾病部分反映了内侧前额叶皮质（mPFC）的失调，但其潜在机制尚不清楚。为了显著推进对这种现象的理解，我们提交了这个R21应用程序，以实现一种新的人类共病大鼠模型，其中模拟HIV+和可卡因滥用的关键特征，以研究mPFC神经元的功能状态。研究目标是：（1）揭示非感染性的年轻（10-12周龄）成年HIV-1转基因（Tg）大鼠中mPFC的功能障碍，所述大鼠在脑中长期表达多种HIV-1蛋白毒素，但不表现出在老年Tg大鼠中观察到的明显病理（即，10-12个月大）。（2）确定接受可卡因自我给药训练的HIV-1 Tg大鼠mPFC中是否存在夸大的病理生理学。我们的中心假设是，mPFC锥体神经元更容易过度激活可卡因自我管理的Tg大鼠比盐水治疗的Tg大鼠或可卡因自我管理的非Tg大鼠。我们将用两个具体目标来检验这个假设。目的1将验证mPFC中的[小胶质细胞增生水平]，并确定其与年轻成年Tg大鼠中通过过度激活的L型Ca 2+通道介导的异常增强的神经元兴奋性的相关性。非Tg大鼠作为对照。将使用膜片钳记录技术在离体脑切片中评估mPFC锥体神经元的功能活性。我们预计，Tg大鼠将显示[mPFC小胶质细胞增生]和过度激活的L-通道介导的锥体神经元的过度兴奋性，反映了对兴奋性刺激的反应异常增加。目的2将确定可卡因自身给药增强在Tg大鼠中观察到的锥体细胞病理生理学。我们预计，可卡因将加剧过度兴奋的mPFC锥体神经元中观察到的Tg大鼠。这项研究是重要的和创新的，因为它将提供第一种手段来确定可卡因自我管理条件下慢性脑暴露的HIV-1蛋白的功能后果;这样做，它将提供一种全新的方法来调查负责这种共病的分子和细胞机制。预计到两年结束时的结果将确定HIV-1蛋白诱导的病理学和可卡因滥用通过过度激活的L-通道会聚到mPFC神经元功能失调。这些结果将指导我们未来的调查机制失调的Ca 2+稳态mPFC。因此，这项大胆的研究将垂直提升我们对可能导致HAND神经发病机制以及与HIV+和可卡因滥用相关的神经精神疾病的机制的理解。这一新的知识也将导致R 01的应用，其中将开发新的治疗策略以减少这种病理。 公共卫生相关性： 可卡因滥用和艾滋病的结合加速了单独伴随任何一种情况的脑损伤。不幸的是，这种组合的频率，或共病，它是在我们的社会增加。该项目将确定在有或没有可卡因自我给药的情况下，艾滋病毒在大鼠大脑中产生的有毒病毒蛋白如何改变麸皮区域（内侧前额叶皮层）神经元的功能，而在人类中，该区域易受艾滋病毒感染和可卡因滥用的影响。我们认为，可卡因对正常神经元放电至关重要的特定蛋白质会增强HIV毒素的有害影响。通过确定可卡因和艾滋病毒毒素的共同分子靶点，该项目的成果应证明对开发治疗手段以减缓可卡因滥用对艾滋病毒/艾滋病并发症的破坏以及促进这些人的药物戒断至关重要。

DESCRIPTION (provided by applicant): Cocaine-abusing, HIV+ individuals experience more severe and rapidly evolving neuropsychiatric disorders and HIV-associated neurocognitive disorders (HAND) than non-abusing HIV+ individuals. These disorders reflect in part, a dysregulation of the medial prefrontal cortex (mPFC), but the underlying mechanisms are unclear. To significantly advance understanding of this phenomenon, we submit this R21 application to implement a new rat model of the comorbid human condition wherein critical features of both HIV+ and cocaine abuse are emulated to investigate the functional state of mPFC neurons. The research objectives are: (1) To reveal dysfunction of the mPFC in non-infectious, young (10-12 week old) adult HIV-1 transgenic (Tg) rats that chronically express multiple HIV-1 protein toxins in the brain, but do not exhibit the overt pathologies seen in old Tg rats (i.e., 10-12 months of age). (2 To determine if an exaggerated pathophysiology exists in the mPFC of HIV-1 Tg rats trained to self-administer cocaine. Our central hypothesis is that mPFC pyramidal neurons are more prone to over-activation in cocaine self-administering Tg rats than in saline-treated Tg rats or cocaine self-administering non-Tg rats. We will test this hypothesis with two Specific Aims. Aim 1 will validate [the level of microgliosis] in the mPFC, and determine their association with abnormally- enhanced neuronal excitability mediated via over-activated L-type Ca2+ channels in the young adult Tg rats. Non-Tg rats will serve as controls. Functional activity of mPFC pyramidal neurons will be assessed in ex vivo brain slices using patch-clamp recording techniques. We expect that the Tg rats will show [mPFC microgliosis] and hyper-excitability of pyramidal neurons mediated by over-activated L-channels, reflected by abnormally-increased responses to excitatory stimuli. Aim 2 will determine that cocaine self- administration enhances the pyramidal cell pathophysiology seen in the Tg rats. We expect that cocaine will exacerbate the hyper-excitability of mPFC pyramidal neurons observed in the Tg rats. This research is significant and innovative because it will provide the first means to ascertain the functional consequences of the chronic brain exposure of HIV-1 proteins under conditions of cocaine self-administration; in so doing, it will provide a completely novel method to investigate the molecular and cellular mechanisms responsible for this comorbid condition. The outcomes expected by the end of two years will determine that the HIV-1 proteins-induced pathology and cocaine abuse converge to dysregulate mPFC neuronal function via over- activated L-channels. These outcomes will guide our future investigations on mechanisms underlying the dysregulated Ca2+ homeostasis in the mPFC. Thus, this bold research will vertically elevate our understanding of the mechanisms that may contribute to the neuropathogenesis of HAND and neuropsychiatric disorders associated with HIV+ and cocaine abuse. This new knowledge will also lead to a R01 application in which novel therapeutic strategies will be developed to reduce such pathology. PUBLIC HEALTH RELEVANCE: The combination of cocaine abuse and AIDS accelerates the brain damage that can accompany either condition alone. Unfortunately, the frequency of this combination, or comorbidity, it is increasing in our society. This project will determine how toxic viral proteins produced by HIV in the rat brain, with or without cocaine self- administration, alter the function of neurons in a bran region (the medial prefrontal cortex) which, in humans, is vulnerable to both HIV infection and cocaine abuse. We propose that the detrimental effects of HIV toxins will be potentiated by cocaine on specific proteins that are critical for normal neuronal firing. By identifying common molecular targets of cocaine and HIV toxins, outcomes from this project should prove to be critically important in developing therapeutic means to slow the devastation of HIV/AIDS comorbidity with cocaine abuse, as well as to promote drug abstinence in these individuals.