Interaction of HIV-Tat and methamphetamine: Role of ion channels and epigenetics

描述(申请人提供)：甲基苯丙胺(冰毒)是艾滋病毒感染者常用(和滥用)的一种非法药物。冰毒会加剧艾滋病毒相关的神经损伤和脑损伤。临床研究表明，与单独使用艾滋病毒或冰毒相比，艾滋病毒和冰毒对神经元丢失和胶质细胞激活具有相加的影响。最近的发现还表明，APOE4抑制K+通道的活动，而冰毒则引起动作电位的爆发。ApoE4是ApoE？4等位基因的产物，是阿尔茨海默病的危险因素。APOE？4等位基因也与加速HIV疾病的进展有关。到目前为止，还没有研究调查APOE基因多态如何在HIV感染和联合使用冰毒的情况下影响中枢神经系统损伤的性质。我们的长期目标是阐明在艾滋病毒感染和这些人通常滥用的药物存在的情况下，基因变异的作用及其对大脑的影响。这项拟议工作的目的是更好地了解APOE蛋白、HIV-TAT蛋白和冰毒之间的相互作用，从而通过破坏电和生理反应来促进神经元损伤。我们的总体假设是，APOE亚型的差异表达将通过直接影响电活动从而影响细胞内钙(Ca~(2+))平衡来决定HIV-TAT(在HIV感染期间)和METH诱导的神经损伤的严重程度。在目标1中，我们将研究APOE？4等位基因(？4-)携带者(？4+)和非携带者(？4-)的死后脑组织DNA甲基化模式。我们将确定甲基苯丙胺的使用如何改变？4+和？4-HIV患者的APOE启动子和外显子4 CpG岛的DNA甲基化模式。在目标2中，我们将通过监测神经元的电活动(钙、钠、钾电流和静息膜电位)来检测神经元在APOE3和APOE4蛋白存在的情况下对TAT和METH的反应。为了实现这一点，我们将使用全细胞膜片钳记录(在电压钳和电流钳模式下)测量宏观的钙、钠、钾电流和膜电位的变化。这些记录将在不同的APOE异构体背景下进行，有无冰毒。这项研究的数据将成为这位处于研究生涯早期的新调查员申请者未来R01级提案的基础。

DESCRIPTION (provided by applicant): Methamphetamine (METH) is an illicit drug commonly used (and abused) by HIV-infected patients. METH exacerbates HIV-related neurological impairments and brain injury. Clinical studies show that HIV and METH have additive effects on neuronal loss and glial activation compared to either HIV or METH insult alone. Recent findings also demonstrate that APOE4 suppress K+ channel activities while METH elicits bursts of action potentials. APOE4, a product of the APOE ?4 allele, is a risk factor for Alzheimer's Disease. The APOE ?4 allele is also implicated in accelerating the progression of HIV Disease. To date, no study has been conducted to investigate how APOE gene polymorphisms affect the nature of CNS injury in the presence of HIV infection and in combination with METH use. Our long-term goal is to elucidate the role of genetic variations and their effects on the brain in the presence f both HIV infection and the drugs commonly abused by these individuals. The objective of this proposed work is to better understand the interactions between APOE protein, HIV-Tat protein and METH in promoting neuronal injury via disruption of electrical and physiological responses. Our overall hypothesis is that differential expression of APOE isoforms will determine the severity of neural damage induced by HIV-Tat (during HIV infection) and by METH by directly influencing electrical activities and consequently affecting intracellular calcium (Ca2+) homeostasis. In Aim 1, we will characterize the DNA methylation patterns of post-mortem brain tissues of HIV+ and HIV + METH individuals who are carriers (?4+) and non-carriers of the APOE ?4 allele (?4-). We will determine how methamphetamine use changes the DNA methylation patterns of the APOE promoter and exon 4 CpG islands in HIV-individuals who are ?4+ and ?4-. In Aim 2, we will examine neuronal responses to Tat and METH in the presence of APOE3 and APOE4 proteins by monitoring neurons' electrical activities (Ca2+, Na+, and K+ currents and resting membrane potentials). To achieve this, we will measure macroscopic Ca2+, Na+, and K+ currents and membrane potentials changes using whole-cell patch clamp recordings (in voltage clamp and current clamp modes). These recordings will be done in different APOE isoform backgrounds with and without METH. The data from this research will form the basis of a future R01-level proposal for this New Investigator applicant who is at the early stage of her research career.