Mechanisms underlying extracellular vesicle mediated changes in inflammation, neural circuitry and plasticity following cortical injury in aged monkeys

摘要 中风、头部损伤或阿尔茨海默病相关痴呆(ADRD)患者的老年脑变化 导致慢性认知和运动障碍。间充质干细胞(MSCs)最近受到关注 逆转或减缓老化大脑中神经退行性和损伤相关的变化，因为它们抑制了 炎症和促进组织修复和重新髓鞘形成。我们现在已经完成了作为R21的一部分的研究- NS102991和R56-NS112207已表明MSC来源的细胞外小泡(EVS)、活性 MSCs产物促进和促进老年女性皮质损伤后运动功能的恢复 猴子。EV治疗的猴子在受伤后3-5周表现出完全恢复，而未治疗的猴子 伤后8-12周恢复平台期。在慢性恢复阶段(伤后16周，R21- NS102991)，MSC-EVS可减少损伤诱导的小胶质细胞神经炎症、神经元兴奋性毒性、突触 缺失、少突胶质细胞损伤和髓鞘形成缺陷。然而，MSC-EVS在内部运行的确切性质 受伤后的急性或慢性恢复阶段仍不清楚，破译这一点对于 微调MSC-EVS对年龄相关损伤和神经退行性疾病的有效使用。我们的预赛 早期采集的血液和脑组织中与损伤和MSC-EV相关的变化分析 恢复(伤后6周，R56-NS112207)显示早期治疗相关的小胶质细胞差异 16周时观察到的不同于治疗相关差异的表型和神经元兴奋性 受伤后。因此，我们现在建议继续和扩大这些研究，以结合体内行为，MRI 和蛋白质组脑脊液和血液生物标志物的综合蛋白质组和单细胞转录组分析 在不同的时间点采集的脑组织的轮廓和生理和组织学评估 雄性和雌性老年猴的康复(伤后3、6、9周)。此外，使用先进的人类- 衍生的体外模型，我们将阐明特定的包裹MSC-EVS的miRNAs或/和蛋白质 改善损伤相关的炎症和氧化反应，促进康复和神经保护。我们 假设MSC-EV含有调节损伤和急性反应的miRNA和蛋白质信号 减轻直接损害，减少继发性慢性炎症和变性，促进 恢复性微环境，有助于以后恢复的神经可塑性。这些研究将阐明 肠道间充质干细胞作用的时间进程、性别依赖动力学和细胞特异性分子机制(S) 介导性康复，这将为其作为治疗年龄相关性损伤的潜在疗法铺平道路 以及人类的神经退行性疾病。

Abstract Changes in the aged brain that occur with stroke, head injury or Alzheimer’s Disease Related Dementias (ADRD) result in chronic cognitive and motor deficits. Mesenchymal stem cells (MSCs) have recently received attention to reverse or slow neurodegenerative and injury-related changes in the aging brain as they suppress inflammation and facilitate tissue repair and remyelination. We have now completed studies as part of R21- NS102991 and R56-NS112207 that have shown that MSC-derived extracellular vesicles (EVs), the active product of MSCs, accelerate and enhance recovery of motor function following cortical injury in aged female monkeys. EV-treated monkeys exhibited full recovery by 3-5 weeks post-injury and untreated monkeys reached a plateau in recovery by 8-12 weeks post-injury. At a chronic recovery stage (16-weeks post-injury, R21- NS102991), MSC-EVs reduced injury-induced microglial neuroinflammation, neuronal excitotoxicity, synapse loss, oligodendrocyte damage and myelination deficits. However, the precise nature of how MSC-EVs act within both acute or chronic stages of recovery after injury remains unknown and is important to decipher in order to fine tune the efficacious use of MSC-EVs for age-related injury and neurodegenerative diseases. Our preliminary analysis of injury- and MSC-EV-associated changes in blood and brain tissue collected at an earlier stage of recovery (6 weeks post-injury, R56-NS112207) showed early treatment-related differences in microglial phenotypes and neuronal excitability that are distinct from treatment-related differences observed at 16-week post-injury. Therefore, we now propose to continue and expand these studies to combine in vivo behavioral, MRI and proteomic CSF and blood biomarker analyses with comprehensive proteomic and single-cell transcriptomic profiling and physiological and histological assessments of brain tissue harvested at distinct time points during recovery (3, 6, 9 weeks post- injury) from male and females aged monkeys. Furthermore, using advance human- derived in-vitro models, we will elucidate specific encapsulated miRNAs or/and proteins of MSC-EVs that ameliorate injury-related inflammatory and oxidative responses, and facilitate recovery and neuroprotection. We hypothesize that MSC-EVs contain miRNA and protein signals that modulate the acute response to injury and mitigate immediate damage, leading to reduced secondary chronic inflammation and degeneration, promoting a restorative microenvironment that will facilitate neural plasticity later in recovery. These studies will elucidate the temporal progression, sex-dependent dynamics and cell-specific molecular mechanism(s) of action of MSC-EV mediated recovery, that will pave the way for its potential development as a therapeutic for age-related injury and neurodegenerative diseases in humans.