Extracellular Vesicle treatment and age-related neuropathology in non-human primates

摘要 正常衰老的特征是认知缺陷，特别是在记忆(1-6)和执行能力方面 功能。(1，2，7-11)证据表明，这些变化不是广泛的皮质神经元丢失的结果， 而是由于白质髓鞘、轴突、突触和树突的改变和/或丢失，以及 氧化代谢和炎症的变化。(12-18)此外，越来越多的证据表明， 病理性Tau和A-Beta与年龄相关的认知能力下降有关，即使在没有阿尔茨海默病的情况下也是如此 疾病及相关痴呆(ADRD)。因此，一种潜在的疗法--间充质干细胞(MSCs)--具有 最近作为一种可能的衰老干预措施而受到关注(19-22)，因为它们被认为可以抑制炎症 并促进组织修复和重新髓鞘形成。(19，23，24)此外，我们还证明了人类的脐带血- 来源的细胞和MSC来源的细胞外小泡(EVS)，MSCs的活性产物，减少炎症 并促进非人类灵长类动物(NHP)和啮齿动物皮质损伤后运动功能的恢复(25，26) 并在体外促进轴突生长和髓鞘形成。(27-37)类似地，EV已被证明可以改善认知能力 糖尿病大鼠和APP/PS1小鼠(阿尔茨海默病模型)的缺陷。(24，38，39)这些EV是否介导 有益的影响可以应用于正常衰老，灵长类动物与年龄相关的神经病理在很大程度上是未知的。 然而，我们的试点数据显示，在老年雌性恒河猴中使用MSC-EVS会降低A-β 证词。基于这一证据和我们的数据显示EV介导的皮质后恢复 NIH-NIA计划项目，我们以过去三十年的经验为基础 AG00001-34)描述了恒河猴在整个寿命和年龄相关的认知功能 大脑的变化(40，41)，以评估MSC-EVS在我们的恒河猴衰老模型中的影响。具体来说， 我们将研究EVS在延缓或逆转与年龄相关的认知衰退和降低标记物方面的有效性 炎症，髓鞘萎缩，tau和A-Beta沉积。然后我们将量化电动汽车对减排的影响 年龄相关性突触功能障碍和神经元电生理特性的变化。最后，我们会 对治疗和内源性EVS进行深入的蛋白质组学分析，以建立活性EVS的概况 生物货载对治疗效果负责。这项纵向的、多学科的研究将揭示 神经炎性通路、髓鞘损伤与ADRD样病理及认知功能关系的研究 与正常衰老相关的下降，并测试EVS在改善这些与年龄相关的缺陷方面的有效性 神经结构和功能。

ABSTRACT Normal aging is characterized by deficits in cognition particularly in the domains of memory (1-6) and executive function.(1, 2, 7-11) Evidence suggests these changes are not a consequence of widespread cortical neuronal loss, but rather are attributable to alteration and/or loss of white matter myelin, axons, synapses and dendrites, and changes in oxidative metabolism and inflammation.(12-18) Further there is growing evidence that accumulation of pathological Tau and A-Beta are related to age-related cognitive decline, even in the absence of Alzheimer’s Disease and Related Dementias (ADRD). Thus, one potential therapy, mesenchymal stem cells (MSCs), have recently received attention as a possible intervention in aging,(19-22) as they are known to suppress inflammation and facilitate tissue repair and remyelination. (19, 23, 24) Further, we have demonstrated that human umbilical- derived cells, and MSC-derived extracellular vesicles (EVs), the active product of MSCs, reduce inflammation and enhance recovery of motor function in non-human primates (NHP) and rodents following cortical injury(25, 26) and promote axonal growth and myelination in vitro.(27-37) Similarly, EVs have been shown to improve cognitive deficits in diabetic rats and APP/PS1 mice (model of Alzheimer’s disease).(24, 38, 39) Whether these EV-mediated beneficial effects can be applied to normal aging and age-related neuropathology in primates is largely unknown. However, our pilot data show that administration of MSC-EVs in aged female rhesus monkeys decreases A-Beta deposition. Based on this evidence and our data showing EV-mediated enhancement of recovery after cortical injury in NHPs, we build upon on our experience over the past three decades (NIH-NIA Program Project AG00001-34) characterizing cognitive function in the rhesus monkey across the life-span and age-related changes in the brain (40, 41) to assess the impact of MSC-EVs in our rhesus monkey model of aging. Specifically, we will investigate the efficacy of EVs to slow or reverse age-related cognitive decline and reduce markers of inflammation, myelin atrophy, and tau and A-Beta deposition. We will then quantify the effects of EVs on reducing age-related synaptic dysfunction and changes in electrophysiological properties of neurons. Finally, we will conduct an in-depth proteomic analysis of treatment and endogenous EVs to establish the profile of the active biological cargo load responsible for treatment efficacy. This longitudinal, multi-disciplinary study will shed light on the relationships of neuroinflammatory pathways, myelin damage and ADRD like pathology and cognitive decline associated with normal aging, and test the efficacy of EVs in ameliorating these age-related deficits in neural structure and function.