Mitochondrial Heteroplasmy as an Endophenotype of HIV-Associated Neurocognitive Disorders

摘要 HIV 相关神经认知障碍 (HAND) 和其他与衰老相关的退行性和代谢性疾病 尽管有抗逆转录病毒治疗，但艾滋病毒感染者 (PLWH) 中的疾病发生频率过高 治疗和病毒学抑制。细胞内能量发生器（线粒体）的异常功能起着重要作用 在这些复杂疾病中发挥着重要作用，但这些异常的基础在很大程度上尚不清楚。 虽然遗传性线粒体 DNA (mtDNA) 突变已被研究与复杂的人类疾病相关， 在个体一生中获得的线粒体 DNA 突变的影响才刚刚开始显现，因为 新一代 DNA 测序技术的力量对于其检测至关重要。存在感 个体每个细胞内多个 mtDNA 拷贝的数量（以及许多共存类型的 mtDNA）定义 线粒体异质性、低频致病性以及常见的异质性突变 随着年龄的增长，即使在健康个体中，也可能会超过导致疾病的组织特异性阈值。 一些研究表明，HIV 期间 mtDNA 突变增加和/或先前存在的异质性扩大 感染和慢性治疗。异质性与认知障碍和其他疾病之间的关联 是在艾滋病毒环境之外进行的。该提案将研究线粒体异质性在 HAND，以及它与已知的衰老和 HAND 相关因素的关联。对这些有更好的理解 这种关系可能会导致新的风险监测和治疗策略，旨在改善线粒体 功能并降低 PLWH 中 HAND 的风险。我们建议利用独特的纵向老化研究 在 PLWH 和类似选择的 HIV(-) 比较人群中，以实现以下具体目标： 1) 比较接受抗逆转录病毒治疗的 PLWH 之间 12 年期间 mtDNA 异质性的变化 HIV 血清阴性个体； 2a) 确定 mtDNA 异质性和生物标志物之间的关系 PLWH 脑脊液炎症、氧化应激和全身铁状态对抑制性的影响 抗逆转录病毒治疗； 2b) 确定 mtDNA 异质性与 mtDNA 拷贝数的关联 PLWH 横断面和纵向分析中神经认知表现的测量。为此， 100 名 PLWH 和 25 名年龄匹配的 HIV 血清阴性个体将接受 mtDNA 和 基线和 10-12 年随访时线粒体 DNA 拷贝数的测量。异质性关联 还将在艾滋病感染者中进行测量的铁状态以及现有的年龄和氧化应激生物标志物。的 我们为此目的组建的团队拥有最先进的下一代测序方法的专业知识， 大群体线粒体 DNA 异质性研究以及神经炎症和铁线粒体基因组学研究 手。

ABSTRACT HIV-Associated Neurocognitive Disorders (HAND) and other aging-related degenerative and metabolic disorders occur with excess frequency among people living with HIV infection (PLWH), despite antiretroviral therapy and virologic suppression. Abnormal function of energy generators within cells (mitochondria) plays an important role in these complex disorders, but the basis for these abnormalities is, for the most part, unknown. While inherited mitochondrial DNA (mtDNA) mutations have been studied in relation to complex human diseases, the impact of mtDNA mutations acquired over the lifespan of an individual is only just beginning to emerge, due to the power of next-generation DNA sequencing technologies that are essential for their detection. The presence of multiple mtDNA copies within each cell in an individual (and hence many coexisting types of mtDNA) defines mitochondrial heteroplasmy, and low-frequency pathogenic, as well as common heteroplasmic mutations increase with age, even in healthy individuals, potentially crossing tissue-specific thresholds for causing disease. Some studies suggest increased mtDNA mutations and/or expansion of pre-existing heteroplasmies during HIV infection and chronic treatment. Associations between heteroplasmy and cognitive disorders and other diseases have been made outside the HIV setting. This proposal will investigate the role of mitochondrial heteroplasmy in HAND, as well as its association with known correlates of aging and HAND. A better understanding of these relationships may lead to novel risk-monitoring and treatment strategies aimed at improving mitochondrial function and reducing the risk of HAND in PLWH. We propose to leverage a unique, longitudinal aging study among PLWH, and a similarly selected HIV(-) comparison population to implement the following Specific Aims: 1) Compare changes in mtDNA heteroplasmy over a 12-year period between PLWH on antiretroviral therapy and HIV-seronegative individuals; 2a) Determine relationships between mtDNA heteroplasmy and biomarkers of cerebrospinal-fluid inflammation, oxidative stress, and systemic iron status in PLWH on suppressive antiretroviral therapy; and 2b) Determine associations of mtDNA heteroplasmy with mtDNA copy number and measures of neurocognitive performance in cross-sectional and longitudinal analyses in PLWH. For this purpose, 100 PLWH and 25 age-matched HIV-seronegative individuals will undergo deep sequencing of mtDNA and measurement of mtDNA copy number at baseline and 10-12-yr follow-up visits. Heteroplasmy associations with measured iron status and existing age- and oxidative stress biomarkers will also be performed in PLWH. The team we have assembled for this purpose has expertise in state-of-the-art next-generation sequencing methods, mtDNA heteroplasmy studies in large cohorts, and in iron-mitochondrial genomics of neuroinflammation and HAND.