Brain metabolic imaging biomarkers of HIV-1 Infection During ART

项目总结/摘要 我们的目标是部署新的磁共振成像（MRI）技术，以非侵入性跟踪抗逆转录病毒药物 抗逆转录病毒药物（ARV）在中枢神经系统中的作用，并测量与神经病理和 抗逆转录病毒药物的神经保护效果。MRI技术采用了一种新的对比度， 化学交换饱和转移（CEST）。当生物分子的可交换质子 磁饱和并通过化学交换转移到水中，导致信号降低。连续 与大量水质子的交换导致放大的信号降低 生物分子基于CEST的MRI提供代谢物的特异性检测，并具有更高的灵敏度和空间分辨率。 与磁共振波谱（MRS）相比，事实上，我们的初步数据表明， 小鼠大脑中肌醇和谷氨酸的CEST MRI，这是神经胶质激活的标志物，也是一种主要的 兴奋性神经递质。利用抗逆转录病毒药物的CEST对比，我们成功地检测到 药物在中枢神经系统中的作用。基于这些结果，我们研究了肌萎缩侧索硬化的神经病理学标志物。 肌醇和谷氨酸可以使用非侵入性成像来测量并与ART CNS生物分布相关联 技术.成像技术将部署在艾滋病毒感染的人源化小鼠，包括那些动物 富含人类小胶质细胞这些动物对于临床前研究至关重要，以确定HIV相关的 神经病理学和ART相关的神经保护活性。成像技术可以转化为临床 优化后的研究。目标1.谷氨酸盐和肌醇将使用MRI测量， CEST对比用组合ART（cART）治疗的HIV感染的人源化小胶质细胞小鼠。我们 假设谷氨酸和肌醇改变成像结果反映了病毒诱导的神经病理学 作为疾病的生物标志物。谷氨酸和肌醇的CEST对比将首先在体外表征 随后进行体内测试。三维（3D）CEST MRI序列将基于体外 结果并用于同时测量HIV感染者全脑中的谷氨酸和肌醇 用cART治疗的人源化小胶质细胞小鼠。目标2.将使用CEST MRI测量CNS中的ARV水平 感染的老鼠。这些结果将被测试与aim 1中未发现的代谢成像标记物的相关性， 研究ART对神经病理学/神经保护结果的影响。病毒、免疫（CD 4 + T细胞）数据将 并与代谢物和ART的成像结果进行比较。假设是， 抗逆转录病毒药物的生物利用度/生物分布与神经病理学的缓解有关。 总体目标是开发CEST作为神经HIV-1病理学测量的可靠生物标志物， ART神经保护。该项目为neuroHIV的临床前研究提供了必要的工具， 用于未来的人类临床研究。

Project Summary/Abstract Our goal is to deploy novel magnetic resonance imaging (MRI) techniques to noninvasively track antiretroviral drugs (ARVs) in the CNS and measure virus-associated metabolites linked to neuropathological and neuroprotective outcomes resulting from ARVs. The MRI techniques employ a novel contrast coined as “chemical exchange saturation transfer (CEST)”. CEST is seen when an exchangeable proton of a biomolecule is magnetically saturated and transferred to water by chemical exchange causing signal reduction. Continuous exchange with bulk water protons leading to amplified signal reduction enables the detection of the signature biomolecule. CEST-based MRI provides specific detection of metabolites and greater sensitivity and spatial resolution compared to magnetic resonance spectroscopy (MRS). Indeed, our preliminary data demonstrate CEST MRI of myo-inositol and glutamate in mouse brains, which are a marker of glial activation, and a primary excitatory neurotransmitter, respectively. Employing the CEST contrasts of ARVs, we have successfully detected the drugs in the CNS using MRI. Based on these results, we posit neuropathological markers of altered myo- inositol and glutamate can be measured and linked to ART CNS biodistribution using noninvasive imaging techniques. The imaging techniques will be deployed in HIV-infected humanized mice including those animals enriched for human microglia. These animals are critical for preclinical studies to determine HIV-associated neuropathology and ART-linked neuroprotective activities. The imaging techniques can be translated to clinical research after optimization. Aim 1. Glutamate and myo-inositol will be measured using MRI employing their CEST contrasts in HIV-infected humanized microglial mice treated with combination ART (cART). We hypothesize that imaging results of glutamate and myo-inositol alterations reflect virus induced neuropathology as biomarkers of disease. The CEST contrasts of glutamate and myo-inositol will be first characterized in vitro followed by in vivo testing. There-dimensional (3D) CEST MRI sequences will be developed based on the in vitro results and used to measure the glutamate and myo-inositol simultaneously in the whole brain of HIV-infected humanized microglial mice treated with cART. Aim 2. ARV levels in the CNS will be measured using CEST MRI in infected mice. The results will be tested for association with metabolic imaging markers uncovered in aim 1 to study the effects of ART on neuropathological/neuroprotective outcomes. Viral, immune (CD4+ T cell) data will be acquired and compared with imaging results of metabolites and ART. The hypothesis is that the bioavailability/biodistribution of ARVs are associated with the mitigation of neuropathology. The overarching goal is to develop CEST as a reliable biomarker for measures of neuroHIV-1 pathology and ART neuroprotection. The project provides essential tools for preclinical studies of neuroHIV that can be translated for future human clinical research.