Stress Granule Formation in the Antiretroviral-Mediated Dysregulation of Oligodendrocyte Maturation in HIV-HAND

项目摘要 大约一半的艾滋病毒感染者（PWH）会经历艾滋病毒相关的神经认知障碍（HAND）， 表现为一系列神经认知障碍虽然大多数PWH在美国是 病毒被抑制或检测不到，具有HAND症状的PWH的总体比例保持不变。 不变HAND的特征之一是白色物质的萎缩，这是HAND中持续存在的病理 在PWH中ART治疗的持续时间已被证明与观察到的 白色物质的损失，导致药物本身引起这种病理学的担忧。衰减 白色物质的减少与髓鞘的损失有关，髓鞘在CNS中由少突胶质细胞（OL）产生。 髓鞘是跳跃式传导和轴突营养支持所必需的，它的缺失可能导致神经元的突触损伤。 在手部观察到的临床变化。我们实验室以前的工作已经证明，选择ART药物可以防止 少突胶质细胞的成熟和髓鞘形成，尽管这些观察结果的机制需要 额外的调查。我们进一步表明，用选择的ART药物治疗成熟的OL，如 Elvitegravir（EVG）激活综合应激反应（ISR），抑制ISR可恢复OL 在EVG存在下的分化。ISR是真核生物中用于恢复稳态的适应性途径。 在应激条件下的细胞，有时以细胞质应激颗粒的形成为特征 (SGs)，无膜细胞器被认为有助于翻译的全面抑制。压力颗粒没有 但对其他神经退行性疾病的研究发现， 它们在神经元中的存在可能会加速神经退化。在慢性压力下，SG可以 变得持久，并且mRNA和蛋白质的长期聚集可能成为病理性的。有 强有力的证据将神经元中的慢性SG积累与肌萎缩侧索硬化症（ALS）相关联， 老年痴呆和额颞叶痴呆。本实验室还在HIV+的死后白色物质中观察到SG 神经认知障碍患者。此外，我的初步数据表明，成熟的OL治疗 EVG不仅激活ISR，而且形成SGs，这些SGs随着ISR抑制而消失。我假设在 抗逆转录病毒药物治疗，应激颗粒通过PERK激活阻断OLs成熟所需的mRNA， ISR，这些颗粒的形成是为了防止细胞死亡。我将通过三个具体目标来检验这个假设。目的 1：我将确定ARV药物是否通过PERK激活的ISR以OL形式诱导应激颗粒。目标2：我会 确定在ARV药物暴露期间SG形成对OL存活的贡献。目标3：确定 是否ARV诱导的SGs在OLs中隔离成熟和髓鞘形成所需的mRNA。由于应力 颗粒以前在少突胶质细胞中没有特征，这项工作不仅将提供对 改善ART治疗PWH的结果，但也将有利于其他神经系统疾病的研究 以失去白色物质为特征。

PROJECT SUMMARY HIV-Associated Neurocognitive Disorder (HAND) is experienced by about half of people living with HIV (PWH), and presents as a spectrum of neurocognitive impairments. While the majority of PWH in the United States are virally suppressed or undetectable, the overall proportion of PWH with HAND symptoms has remained unchanged. One of the hallmarks of HAND is the atrophy of white matter, a pathology that persists in HAND patients treated with ART. The duration of ART treatment in PWH has been shown to correlate to the observed loss of white matter, leading to the concern that the drugs themselves are causing this pathology. The attenuation of white matter is associated with a loss of myelin, which in the CNS is produced by oligodendrocytes (OLs). Myelin is necessary for saltatory conduction and trophic support of axons and its loss may contribute to the clinical changes seen in HAND. Previous work from our lab has demonstrated that select ART drugs prevent the maturation of oligodendrocytes and myelination, though the mechanisms underlying these observations require additional investigation. We have further shown that treating maturing OLs with select ART drugs, such as Elvitegravir (EVG), activates the Integrated Stress Response (ISR), and inhibition of the ISR restores OL differentiation in the presence of EVG. The ISR is an adaptive pathway used to restore homeostasis in eukaryotic cells under stressful conditions, and is sometimes characterized by the formation of cytoplasmic stress granules (SGs), membraneless organelles thought to aid in the global inhibition of translation. Stress granules have not yet been extensively studied in oligodendrocytes, but research of other neurodegenerative diseases has found that their presence in neurons may cause acceleration of neurodegeneration. During chronic stress, SGs can become persistent, and the long-term aggregation of mRNAs and proteins can become pathological. There is strong evidence associating chronic SG accumulation in neurons with amyotrophic lateral sclerosis (ALS), Alzheimer’s, and frontotemporal dementia. Our lab has also observed SGs in post-mortem white matter of HIV+ patients with neurocognitive impairment. Furthermore, my preliminary data has shown that maturing OLs treated with EVG not only activate the ISR, but also form SGs that disappear with ISR inhibition. I hypothesize that during ARV drug treatment, stress granules sequester mRNAs needed for maturation of OLs via PERK activation of the ISR, and that these granules form to prevent cell death. I will test this hypothesis via three specific aims. AIM 1: I will determine if ARV Drug induced stress granules in OLs form via the PERK activated ISR. AIM 2: I will determine the contribution of SG formation to OL survival during ARV drug exposure. AIM 3: I will determine whether ARV-induced SGs in OLs sequester mRNAs needed for maturation and myelination. Since stress granules have not previously been characterized in oligodendrocytes, this work will not only provide insight into improving outcomes of ART treated PWH, but will also benefit research of other neurological diseases characterized by loss of white matter.