Effects of opiates on neurons and their impact on HIV neuropathology

描述(申请人提供)：这项研究的重点是最近发现的阿片类药物的作用--即它们调节神经元中蛋白质铁蛋白重链(FHC)的能力--及其对艾滋病毒神经病理学的贡献。这项建议的具体目标是：a)收集阿片类药物吸毒者(DU)脑内FHC变化的证据，并研究FHC在HIV神经病理中的潜在作用；b)阐明吗啡调节神经元FHC表达的机制。这项研究的长期目标是进一步探索HIV/DU患者神经元功能障碍的生物学基础。需要检验的一般假设是，阿片剂滥用会使神经元更容易受到有毒刺激和/或改变其对破坏性侮辱的反应能力，从而加剧艾滋病毒的神经病理。从机制上讲，这可能是由于神经元中FHC的异常增加，从而损害了趋化因子/受体对CXCL12/CXCR4的保护作用。为了验证这些假设，提出了强大的技术，即多光谱成像和激光捕获显微切割，以及体外和体内/体外实验方法，在三个特定的目标下。目标1的研究集中在HIV/DU患者尸检脑组织中FHC的表达-主要目的是确定药物滥用是否改变了人脑中FHC的水平，主要是在皮质神经元中。这些研究还有望提供有关FHC变化与HIV/DU患者神经功能障碍的相关性的信息。目的2中讨论的实验重点是吗啡诱导的FHC对培养的动物脑组织和皮质神经元中CXCR4功能的影响。其目标是用在人体上不可行的对照实验来补充目标1的研究。这些研究将探讨吗啡对FHC的细胞(即神经元/胶质细胞)和亚细胞(胞浆/核)的分布，以及影响FHC与CXCR4相互作用和调节CXCR4的能力及其机制。最后，目标3将解决涉及吗啡和艾滋病毒对FHC作用的分子机制(如FHC的转录后调节和铁蛋白铁结合特性的作用)，这是在艾滋病毒神经病理学的背景下理解吗啡这一新作用的生物学意义的重要一步。总体而言，这项拟议的研究将提供关于FHC作为神经元功能和存活调节因子的新角色的基本信息，确定该蛋白是否是神经元上阿片类药物作用的相关靶点，并表征这一作用的后果和涉及神经病理学的一些机制。通过表征FHC在神经元功能障碍中的作用，并确定阿片类药物对FHC调节的机制基础，本研究将为旨在预防或减少HIV感染的神经系统并发症的治疗干预提供新的途径。 公共卫生相关性：尽管目前的抗逆转录病毒治疗有好处，但艾滋病毒感染的神经并发症，包括神经认知和运动/感觉缺陷，仍然是一个未得到满足的医疗和社会需求--部分原因是这些复杂疾病的生物学基础仍未确定。在这项申请中提出的研究将表征阿片剂对神经元的特定影响，这些神经元干扰正常的神经元功能，并可能导致神经元改变和艾滋病毒神经认知障碍。因此，这项研究将提供新的治疗策略，旨在减少吸毒者--现代艾滋病毒感染患者的一个重要群体--感染艾滋病毒的神经并发症，并为一般艾滋病毒患者的最佳管理提供新的见解。

DESCRIPTION (provided by applicant): This research focuses on a recently discovered effect of opiates - i.e. their ability to regulate the protein ferritin heavy chain (FHC) in neurons - andits contribution to HIV neuropathology. The specific objectives of this proposal are: a) to collect evidence of FHC changes in the brain of opiate drug users (DU) and examine the potential role of FHC in HIV neuropathology, and b) to elucidate the mechanisms involved in the regulation of neuronal FHC expression by morphine. The long-term goal of this research is to further explore the biological basis of neuronal dysfunction in HIV/DU patients. The general hypothesis to be tested is that opiate abuse exacerbates HIV neuropathology by rendering neurons more vulnerable to toxic stimuli and/or by altering their ability of responding to damaging insults. Mechanistically, this could be caused by abnormal increase of FHC in neurons and consequent impairment of the protective actions of the chemokine/receptor pair CXCL12/CXCR4. To test these hypotheses powerful techniques, i.e. Multispectral Imaging and Laser Capture Microdissection, along with in vitro and in vivo/ex vivo experimental approaches are proposed, within three specific aims. Studies in aim 1 focus on the expression of FHC in autopsy brain tissue from HIV/DU patients - with the primary intent of establishing whether drug abuse alters FHC levels in the human brain, mainly in cortical neurons. These studies are also expected to provide information about the correlation of FHC changes with neurological disorders in HIV/DU patients. The experiments discussed in aim 2 focuses on the consequences of morphine-induced FHC on CXCR4 function in animal brain tissue and cortical neurons in culture. The goal is to complement aim 1 studies with controlled experiments that are not feasible in humans. These studies will investigate the cellular (i.e. neurons/glia) and subcellular (cytosol /nucleus) distribution of FHC in response to morphine, which influence FHC ability to interact with and modulate CXCR4, and the mechanisms involved. Finally, aim 3 will tackle the molecular mechanisms involved in the action of morphine and HIV on FHC (such as posttranscriptional regulation of FHC and the role of ferritin iron binding properties), which is an important step toward understanding of the biological implications of this novel action of morphine in the context of HIV neuropathology. Overall, the proposed research will provide essential information about a novel role of FHC as a regulator of neuronal function and survival, determine if this protein is a relevant target of opiate action on neurons, and characterize both the consequences of this action and some of the mechanisms involved in neuropathology. By characterizing the role of FHC in neuronal dysfunction and identifying the mechanistic basis of opiates action on FHC regulation, this research will provide new avenues for therapeutic intervention aimed at preventing or reducing the neurological complications of HIV infection. PUBLIC HEALTH RELEVANCE: Despite the benefits of current antiretroviral treatments, the neurological complications of HIV infection, which include both neurocognitive and motor/sensory deficits, remain an unmet medical and social need - partly because the biological bases of these complex disorders are still undefined. The studies proposed in this application will characterize specific effects of opiates on neurons that interfere with normal neuronal function and may contribute to neuronal alteration and HIV neurocognitive impairment. As such, this research will offer new therapeutic strategies aimed at reducing the neurological complications of HIV infection in drug users, a significant group of HIV-infected patients in modern times, as well as provide new insights for best management of HIV patients in general.