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

项目摘要 阿尔茨海默病（AD）是一种进行性神经退行性脑疾病，其损害记忆和认知功能， 功能协调发展的它是65岁以上老年人中最常见的痴呆症，据估计， 5.8数百万美国人可能患有由AD引起的痴呆症。虽然AD的发病机制尚不清楚，但异常 淀粉样β蛋白（Aβ）斑块和过度磷酸化的tau蛋白在整个大脑中的沉积被认为是 在神经炎症、突触丧失和神经元细胞死亡中起作用。虽然Aβ呈弥漫性扩散， 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，这可能是由于 神经炎症作用。此外，神经炎症可能直接诱导或加重Aβ和tau蛋白 蛋白质病，从而使神经炎症恶化并导致突触和神经元的进一步损失， 形成一个恶性循环，可能会促进疾病的进展。然而，在这一过程中 磷酸化tau的增殖及其与神经炎症的相互作用仍然是难以捉摸的。区分这些 在存在众多混杂信号的体内，相互分离复杂因素是极其具有挑战性的。 因此，需要新的方法来弥合这一差距，以揭示潜在的机制 异常蛋白质的转运和神经炎症通过其加速AD的进展。 为了满足这一需求，我们将采用一种微流体体外平台与一种新的三元培养相结合， （初级神经元、星形胶质细胞、小胶质细胞）神经炎症的大鼠模型，其已被开发作为神经炎症的一部分。 PI当前的R 03奖。微流体平台由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 使得两种文化之间的突触连接。这一行政补充的直接目标是 是研究神经胶质细胞和炎症对异常tau蛋白运输的贡献。具体地说， 我们将（i）确定Aβ和磷酸化人tau（由转染的神经元表达）对 （ii）采用微流体平台来解耦三培养模型中的神经炎症的影响， Aβ添加本身和Aβ触发的神经炎症对tau蛋白沿着沿着连接神经元的轴突束传播的影响 两种培养物保持在初级室和次级室中。本文所述的试点研究预计 （i）鉴定添加到培养物和/或人tau表达中的致病性构象Aβ的影响 通过转染的神经元对神经炎症的影响，（ii）解耦致病性Aβ本身或其 相应的神经炎性细胞因子谱对致病性tau通过轴突束传播的影响，和（iii） 为将来神经炎症和轴突之间相互作用的机制研究奠定基础 在阿尔茨海默病的背景下致病性tau的转运。

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.