The role of VMAT-2 in mediating the impact of HIV-1 protein Tat and methamphetamine on dopamine neurotransmission and behavior

项目摘要 HIV-1转录反式激活因子(TAT)蛋白引起的多巴胺能功能失调 与HIV-1相关的神经认知障碍(HAND)的进展有关。TAT调停 增加多巴胺(DA)的释放，并作为多巴胺转运体的负变构调节器 (DAT)。除了DAT，以前的工作已经确定TAT是囊泡的负变构调节器 单胺转运体(VMAT-2)。VMAT-2的功能是将DA重新打包为囊泡，以供后续释放。 抑制VMAT-2可导致DA神经传递的失调，从而导致DA和 细胞凋亡。精神刺激剂甲基苯丙胺(METH)除了TAT外，还抑制VMAT-2的功能。冰毒 在HIV-1感染者中是一种高度滥用的精神刺激剂。已经证明了TAT蛋白的表达 以增强冰毒引起的神经毒性和行为。考虑到TAT或TAT之间的各自相互作用 Meth和VMAT-2，我们假设Tat和Meth对细胞外DA和行为的影响是 由VMAT-2介导。我们将首先通过确定VMAT-2在调节TAT-2中的作用来解决这一假设。 诱导DA释放增加(单独使用TAT)。我们将使用快速扫描循环伏安法来量化DA的释放 表达TAT的小鼠。具体地说，我们将描述VMAT-2抑制剂的药理反应 确定TAT表达是否会改变VMAT-2功能。其次，我们将使用两种不同的冰毒 第一个目标是建立给药模型(急性和慢性)，并描述对VMAT-2抑制剂的反应。 最后，我们将确定VMAT-2特异性抑制剂是否减弱TAT增强的甲基化条件 放置偏好行为。这将使我们深入了解VMAT-2是否介导了TAT增强的冰毒行为。这个 这项提案的发现将为TAT增加的分子机制提供关键的洞察力 细胞外DA并确定VMAT-2是否为未来治疗干预的合适药物靶点 艾滋病毒-1感染者滥用冰毒的治疗。 。

Project Summary Dysregulation of dopaminergic function due to the HIV-1 transactivator of transcription (Tat) protein has been implicated in the progression of HIV-1 associated neurocognitive disorders (HAND). Tat mediates increases in dopamine (DA) release and acts as a negative allosteric modulator for the dopamine transporter (DAT). In addition to DAT, previous work has identified Tat as a negative allosteric modulator for the vesicular monoamine transporter (VMAT-2). VMAT-2 functions to repackage DA into vesicles for subsequent release. Inhibition of VMAT-2 causes dysregulation of DA neurotransmission which can lead to autooxidation of DA and apoptosis. The psychostimulant methamphetamine (METH), in addition to Tat, inhibits VMAT-2 function. METH is a highly abused psychostimulant among HIV-1 infected persons. Expression of the Tat protein has been shown to potentiate METH induced neurotoxicity and behavior. Considering the respective interactions between Tat or METH and VMAT-2, we hypothesize that the Tat and METH effects on extracellular DA and behavior are mediated by VMAT-2. We will address this hypothesis by first, determining the role for VMAT-2 in mediating Tat- induced increases in DA release (Tat alone). We will use fast scan cyclic voltammetry to quantify DA release in Tat expressing mice. Specifically, we will profile the pharmacological response to a VMAT-2 inhibitor to determine whether Tat expression alters VMAT-2 function. Second, we will use two different METH administration models (acute and chronic) and profile the response to the VMAT-2 inhibitor as in the first aim. Lastly, we will determine whether a VMAT-2 specific inhibitor attenuates Tat-potentiated METH-conditioned place preference behavior. This will give insight whether VMAT-2 mediates Tat-potentiated METH behavior. The findings from this proposal will provide key insight into the molecular mechanism by which Tat increases extracellular DA and determine whether VMAT-2 is a suitable drug target for future therapeutic intervention in the treatment of METH abuse in HIV-1 infected persons. .