Interplay of Neuroinflammation and Tau Transport in a Microfluidic Primary Neural Cell Tri-Culture Model

项目总结 阿尔茨海默病(AD)是一种进行性神经退行性脑疾病，损害记忆和认知 功能。它是65岁以上老年人中最常见的痴呆症，据估计，超过 580万美国人可能患有AD引起的痴呆症。而阿尔茨海默病的发病机制尚不清楚，异常 大脑中淀粉样蛋白β(Aβ)斑块和过度磷酸化的tau蛋白的沉积被认为是 在神经炎症、突触丢失和神经细胞死亡中起作用。而β似乎是以扩散的方式传播的 以这种方式，磷酸化的tau蛋白被假设在突触连接的神经元之间传播。 最近的研究表明，Aβ的存在可能会增加传播速度，可能是由于 神经炎症效应。此外，神经炎症可直接诱发或加重Aβ和Tau 蛋白质病，从而加重神经炎症，导致突触和神经元的进一步丧失， 造成恶性循环，可能会促进疾病的发展。然而，其背后的确切机制 增殖的磷酸化tau及其与神经炎症的相互作用仍然难以捉摸。区分这两个 在体内存在大量混杂信号的情况下，来自彼此的复杂因素是极其具有挑战性的。 因此，需要新的方法来弥补这一差距，以揭示潜在的机制 异常蛋白的运输和神经炎症加速了AD的进展。 为了满足这一需求，我们将采用微流控体外平台和一种新的三种培养方法相结合。 (初级神经元、星形胶质细胞、小胶质细胞)大鼠神经炎症模型 PIS的当前R03奖。微流控平台包括两个物理上不同的培养室(例如， 初级和次级)，对应于通过微通道互连的近端和远端解剖区域 允许两种文化之间的突触连接。这份行政副刊的近期目标是 研究神经胶质细胞和炎症在异常tau蛋白运输中的作用。具体来说， 我们将(I)确定Aβ和磷酸化的人tau(由转基因神经元表达)对 三培养模型中的神经炎症，以及(Ii)使用微流控平台来解耦 β添加本身和Aβ引发的神经炎症对tau沿轴索连接的传播的影响 两种培养物保存在初级和次级腔室中。这里描述的试验性研究是预期的 为了(I)确定致病构象的影响添加到培养物和/或人tau表达的β 通过转基因神经元对神经炎症的影响，(Ii)去偶联致病Aβ本身或其影响 相应的神经炎性细胞因子在致病性tau通过轴索传播中的分布，以及(Iii) 为今后神经炎症和轴突相互作用的机制研究奠定基础 阿尔茨海默病背景下致病tau的运输。

PROJECT SUMMARY Alzheimer’s Disease (AD) is a progressive neurodegenerative brain disorder that impairs memory and cognitive functions. It is the most common dementia among older adults over age 65 and it is estimated that more than 5.8 million Americans may have dementia caused by AD. While the pathogenesis of AD is unclear, abnormal deposits of amyloid-β (Aβ) plaques and hyperphosphorylated tau proteins throughout the brain are thought to play a role in neuroinflammation, synapse loss, and neuronal cell death. While Aβ appears to spread in a diffuse manner, phosphorylated tau proteins are hypothesized to propagate between synaptically connected neurons. Recent studies suggest that the presence of Aβ may increase the rate of propagation, potentially due to neuroinflammatory effects. In addition, neuroinflammation may directly induce or exacerbate Aβ and tau proteinopathies, thereby worsen neuroinflammation and leading to further loss of synapses and neurons, creating a vicious cycle that likely promotes disease progression. However, the exact mechanisms that underlie propagation phosphorylated tau and its interplay with neuroinflammation remain elusive. Distinguishing these complex factors from each other in vivo, where numerous confounding signals exist, is extremely challenging. There is, therefore, a need for new methodologies to bridge this gap for revealing the underlying mechanisms by which transport of aberrant proteins and neuroinflammation accelerate the progression of AD. In order to address this need, we will employ a microfluidic in vitro platform in combination with a novel tri-culture (primary neuron, astrocyte, microglia) rat model of neuroinflammation that have been developed as part of the PIs’ current R03 award. The microfluidic platform consists of two physically distinct culture chambers (e.g., primary and secondary), corresponding to proximal and distal anatomic regions interconnected by microchannels that allow synaptic connectivity between the two cultures. The immediate goal of this administrative supplement is to study the contribution of glial cells and inflammation to the transport of abnormal tau proteins. Specifically, we will (i) determine the influence of Aβ and phosphorylated human tau (expressed by transfected neurons) on neuroinflammation in the tri-culture model, and (ii) employ the microfluidic platform to decouple the influences of Aβ addition itself and the Aβ-triggered neuroinflammation on tau propagation along the axonal tracts connecting the two cultures maintained in the primary and secondary chambers. The pilot study described here is expected to (i) identify the influence of pathogenic conformations Aβ added to the culture and/or human tau expression by transfected neurons on neuroinflammation, (ii) decouple the influence of pathogenic Aβ itself or its corresponding neuroinflammatory cytokine profile on propagation of pathogenic tau via axonal tracts, and (iii) establish the foundation for future mechanistic studies of the interplay between neuroinflammation and axonal transport of pathogenic tau in the context of Alzheimer’s Disease.