Effects of opiates on neurons and their impact on HIV neuropathology

项目摘要/摘要 HIV相关的神经认知障碍(HAND)在病毒抑制的患者中持续存在。手是一种 一种以慢性低水平炎症、兴奋性毒性、 神经毒性HIV蛋白，APP处理过程改变，以及其他加剧神经元结构和 功能。阿片类药物的使用在艾滋病毒患者中很常见，被认为与手部疾病有关，尽管这 仍然存在争议。上一次资助时期的研究表明，吗啡可以通过 通过一种新的、铁依赖的途径改变应用程序的处理。已知有毒应用程序切割产品 减少几个大脑区域的树突，这是学习和记忆的关键媒介。 令人惊讶的是，APP裂解产物对前额叶皮质(PFC)树突棘的影响 一个手头至关重要的领域，还没有得到深入的研究。这个项目将阐明 改变了吗啡和HIV诱导的PCF神经元缺陷的APP处理。研究将揭开 人类免疫缺陷病毒与Aβ蛋白的相互作用及吗啡对APP的影响 加工和手中的脊椎。目标1的研究将集中在Aβ寡聚体对树枝状结构的影响 在存在和不存在HIV神经毒素或吗啡的情况下，PFC神经元中的脊柱结构和功能。 这些体外和体内研究将确定树突棘密度/形态/周转率的有意义的变化 ，并对外源性增加的A-β在这一关键脑区的作用( 内源Aβ的作用将在目标3)中进一步测试。目标2的主要目标是确定 哪些类阿片可以通过调节神经元铁来影响淀粉样蛋白的发生。这些机械论研究 是基于我们最近的发现，表明铁在吗啡介导的树突棘减少中起作用 在大脑皮层神经元。还有一个发现也支持这一观点，即内小体脱酸会导致 胞质Fe2和Aβ。重要的是，胞质Fe2调节APP的表达，同时内溶酶体的pH 调节蛋白质的降解。在目标3中，我们将使用新生成的分子工具来移动APP 对α-裂解途径的处理或阻止β-分泌酶的APP裂解。在中进行功能测试后 在原代培养中，最有希望的结构将在手动物模型的PFC神经元中表达 确定在存在艾滋病毒蛋白/吗啡的情况下，它们如何有效降低Aβ水平，以及是否降低β水平 有助于PFC认知任务的恢复。这一建议将阐明铁依赖的机制。 艾滋病毒/阿片类药物滥用受试者认知能力加速下降，这与抗逆转录病毒治疗的相关性越来越大 接受治疗的患者寿命更长。

Project Summary/Abstract HIV-associated neurocognitive disorders (HAND) persist in virally suppressed patients. HAND is a heterogeneous disease that is characterized by chronic low-level inflammation, excitotoxicity, presence of neurotoxic HIV proteins, altered APP processing, and other factors that aggravate neuronal structure and function. Opioid use is common among HIV+ patients and thought to contribute to HAND, although this remains controversial. Studies from the previous funding period suggest that morphine can augment HAND by altering APP processing through a novel, iron-dependent pathway. Toxic APP cleavage products are known to reduce dendritic spines in several brain areas, which are critical mediators of learning and memory. Surprisingly, the effects of APP cleavage products on dendritic spines of the prefrontal cortex (PFC), which is an area of critical importance to HAND, have not been studied in depth. This project will elucidate the role of altered APP processing in morphine and HIV-induced neuronal deficits in the PCF. Studies will unravel the interaction between HIV and Aβ proteins and determine whether morphine can contribute to alteration of APP processing and spines in HAND. Research in aim 1 will concentrate on the effect of Aβ oligomers on dendritic spine structure and function in PFC neurons, in the presence and absence of HIV neurotoxins or morphine. These in vitro and in vivo studies will define meaningful changes in dendritic spine density/morphology/turnover in PFC neurons, and provide a full assessment of exogenously added Aβ actions in this critical brain area (the role of endogenous Aβ will be further tested in aim 3). The main goal of aim 2 is to establish the extent to which µ-opioids can affect amyloidogenesis through modulation of neuronal iron. These mechanistic studies are based on our recent discoveries suggesting a role for iron in morphine-mediated dendritic spine reduction in cortical neurons. They are also supported by the finding that endosome deacidification leads to increase of cytosolic Fe2+ and Aβ. Importantly, cytosolic Fe2+ regulates APP expression whilst endolysosomal pH modulates protein degradation. In aim 3, we will employ newly generated molecular tools able to shift APP processing to the α-cleavage pathway or prevent APP cleavage by β-secretases. After functional testing in primary cultures, the most promising constructs will be expressed in PFC neurons of HAND animal models to determine how effectively they reduce Aβ levels in the presence of HIV proteins/morphine and if Aβ reduction contributes to recovery of PFC cognitive tasks. This proposal will shed light on iron-dependent mechanisms of accelerated cognitive decline in HIV+/opiate abusing subjects, which is becoming increasingly relevant as ART- treated patients live longer.