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 由于HIV-1转录反式激活因子（达特）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。达特介导 增加多巴胺（DA）释放，并作为多巴胺转运蛋白的负变构调节剂 （DAT）。除了DAT，以前的工作已经确定达特作为一个负变构调节剂的囊泡 单胺转运蛋白（VMAT-2）。VMAT-2的功能是将DA重新包装成囊泡，以供随后释放。 VMAT-2的抑制引起DA神经传递的失调，这可导致DA的自氧化， 凋亡除达特外，精神兴奋剂甲基苯丙胺（METH）还抑制VMAT-2功能。甲基 是一种在HIV-1感染者中高度滥用的精神兴奋剂。达特蛋白的表达已经显示 增强METH诱导的神经毒性和行为。考虑到达特或 METH和VMAT-2，我们假设达特和METH对细胞外DA和行为的影响是 由VMAT-2介导。我们将通过首先确定VMAT-2在介导达特- 诱导DA释放增加（单独达特）。我们将使用快速扫描循环伏安法定量DA释放， 表达达特的小鼠。具体而言，我们将描述对VMAT-2抑制剂的药理学反应， 确定达特表达是否改变VMAT-2功能。其次，我们将使用两种不同的方法 如在第一个目的中那样，将VMAT-2抑制剂施用模型（急性和慢性）并描绘对VMAT-2抑制剂的应答。 最后，我们将确定VMAT-2特异性抑制剂是否减弱Tat增强的MET条件性抑制剂。 位置偏好行为这将提供VMAT-2是否介导Tat增强的METH行为的洞察。的 这项提议的发现将为达特增加的分子机制提供关键的见解 细胞外DA，并确定VMAT-2是否是未来治疗干预的合适药物靶点。 治疗HIV-1感染者中的甲基苯丙胺滥用。 .

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. .