Mir-125b/p53/POX axis and HIV-1 induced neurological damage

描述（由申请人提供）：可卡因是HIV感染者中常用的药物，其使用被认为会加重HIV相关神经认知障碍（HAND），这是艾滋病最具破坏性的并发症之一。已知滥用药物的HIV-1阳性个体患HIV脑炎和临床HIV痴呆症的比例较高;这是HAND的标志。然而，可卡因增强HIV-1在大脑中的这些神经作用的能力的详细分子机制仍有待充分理解。我们提出了一种新的机制介导的细胞microRNA“miR-125 b”和线粒体代谢酶脯氨酸氧化酶（POX）在可卡因和HIV-1诱导的神经元损伤。这是基于我们的初步数据，这些数据证明了在用可卡因和HIV-1包膜糖蛋白-gp 120处理后，人类神经元（原代和细胞系）中miR-125 b的下调。同时，我们还观察到可卡因和gp 120处理的神经元细胞中肿瘤蛋白53（p53）的上调。p53与导致HIV-1感染的中枢神经系统（CNS）中神经元损伤的许多细胞过程有关。值得注意的是，已经证明miR-125 b在神经元细胞中负调节p53。我们的数据还说明了可卡因和gp 120处理的人原代神经元和神经元细胞模型中线粒体代谢酶脯氨酸氧化酶（POX）的上调。由于POX是由p53诱导的，我们认为POX是miR-125 b/p53轴的下游靶点，可能在可卡因和HIV-1诱导的神经元损伤中起关键作用。这是因为POX在脯氨酸催化转化为吡咯啉-5-羧酸酯（P5 C）的过程中产生活性氧物质（ROS）。此外，POX的上调可以增加谷氨酸水平，因为P5 C是谷氨酸的前体。考虑到ROS和谷氨酸水平的增加与神经元损伤有关，我们假设可卡因通过下调miR-125 b和上调POX来增强HIV-1相关的神经元损伤。我们相信我们的提议是非常重要的，因为miR-125 b和POX在HIV相关神经元损伤中的作用以前没有被描述过。因此，这些研究可能揭示一种新的机制，并确定新的治疗靶点，消除神经元损伤的手患者。我们的假设将通过两个具体目标进行检验。目的1：阐明可卡因和HIV-1 gp 120诱导的POX表达上调引起神经元损伤。目的2：检测miR-125 b是神经元细胞中POX的一种新的调节剂。

DESCRIPTION (provided by applicant): Cocaine is a commonly used drug among HIV-infected individuals, and its use has been suggested to worsen HIV-associated neurocognitive disorders (HAND), one of the most devastating complications of AIDS. Drug-abusing HIV-1-positive individuals are known to have higher rates of HIV-encephalitis and clinical HIV dementia; the hallmarks of HAND. However, the detailed molecular mechanisms underlying the ability of cocaine to enhance these neurological effects of HIV-1 in the brain still remains to be fully understood. We propose a novel mechanism mediated by the cellular microRNA "miR-125b" and the mitochondrial metabolic enzyme Proline oxidase (POX) in cocaine and HIV-1 induced neuronal damage. This is based on our preliminary data that demonstrate downregulation of miR-125b in human neurons (both primary and cell lines) upon treatment with cocaine and HIV-1 envelop glycoprotein-gp120. Concurrently, we also observed upregulation of the tumor protein 53 (p53) in cocaine and gp120 treated neuronal cells. p53 has been implicated in many cellular processes leading to neuronal damage in the HIV-1 infected central nervous system (CNS). Notably, miR-125b has been demonstrated to negatively regulate p53 in neuronal cells. Our data also illustrate upregulation of the mitochondrial metabolic enzyme Proline Oxidase (POX) in cocaine and gp120 treated human primary neurons and neuronal cell models. Since POX is induced by p53, we propose that POX is a downstream target of the miR-125b/p53 axis that may play a critical role in cocaine and HIV-1 induced neuronal damage. This is because POX generates reactive oxygen species (ROS) during the catalytic conversion of proline to pyrroline-5-carboxylate (P5C). Additionally, upregulation of POX can increase glutamate levels since P5C is a precursor of glutamate. Given that increased levels of ROS and glutamate are implicated in neuronal damage, we hypothesize that cocaine enhances HIV-1 associated neuronal damage by downregulating miR-125b and upregulating POX. We believe our proposal is highly significant since the roles of miR-125b and POX in HIV associated neuronal damage have not been previously described. Therefore, these studies may uncover a novel mechanism and identify new therapeutic targets for abrogating neuronal damage in HAND patients. Our hypothesis will be tested through two specific aims. Aim 1: Elucidate that cocaine and HIV-1 gp120 induced upregulation of POX induces neuronal damage. Aim 2: Examine that miR- 125b is a novel regulator of POX in neuronal cells.