Role of Astrocyte EAAT2/GLT1 Failure in Alzheimer's Disease Pathogenesis

星形胶质细胞 EAAT2/GLT1 故障在阿尔茨海默病发病机制中的作用

• 批准号: 10594014
• 负责人: David G Cook
• 金额: $ 72.64万
• 依托单位: SEATTLE INST FOR BIOMEDICAL/CLINICAL RES
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10594014
• 关键词: Acceleration; Address; Adenovirus Vector; Affect; Age; Alzheimer' s Disease; Alzheimer' s disease brain; Alzheimer' s disease patient; Amyloid; Amyloid beta-42; Anabolism; Anatomy; Astrocytes; Automobile Driving; Autopsy; Back; Binding; Brain; Brain Pathology; Brain region; Cells; Complement; Data; Dependovirus; Disease; Drug Metabolic Detoxication; Dysmorphology; Electrophysiology (science); Equilibrium; Extracellular Space; Failure; Family; Functional disorder; Gene Expression; Genetic; Glial Fibrillary Acidic Protein; Glutamate Transporter; Glutamates; Glutamine; Goals; Hippocampus; Homeostasis; Impaired cognition; Interneurons; Intervention; Knowledge; Lentivirus; Lentivirus Vector; Measures; Mediating; Memory; Metabolic; Methods; Molecular Target; Morphology; Mus; Neurons; Neurotransmitters; Occupations; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Play; Positioning Attribute; Process; Property; Proteins; Publishing; Pyramidal Cells; Recovery; Reporting; Research; Role; Slice; Specificity; Synapses; Synaptic Transmission; System; Testing; Toxic effect; Work; astrogliosis; cognitive function; excitotoxicity; extracellular; gamma-Aminobutyric Acid; in vivo; insight; mild cognitive impairment; mind control; mouse model; neuron loss; neuropathology; neurotoxic; neurotransmission; novel; patch clamp; prevent; response; single-cell RNA sequencing; synergism; tau Proteins; tau expression; tau-1; transcriptomics; translational potential; transmission process; uptake

Astrocytes are ideally positioned to support neuronal/synaptic needs for trophic factors, metabolic homeostasis, and protection from toxicity. While reactive astrogliosis is a prominent feature of AD, this offers very limited insight about how astrocytes influence the disease process or how they may be harmed. One of the most important functions of astrocytes is to clear extracellular glutamate to prevent excitotoxicity. Glutamate taken up by astrocytes is also used as a metabolic substrate for biosynthesis of other neuro- transmitters like GABA. Thus, there are at least two major ways astrocytic glutamate clearance protects the brain. In cortex and hippocampus, the glutamate transporter Slc1a2 (also called GLT1 or EAAT2) plays the most important role in glutamate clearance. Most, but not all Slc1a2 is in astrocytes. Our research team has shown that: (i) Slc1a2 is disturbed in AD; (ii) Slc1a2 loss in an AD mouse model accelerates onset of cognitive impairment; (iii) A42 slows synaptically-released glutamate uptake in hippo- campal slices; and (iv) mice with reduced astrocytic Slc1a2 display significant transcriptomic overlaps with AD. These data complement strong work from other groups and collectively argue that Slc1a2 dysfunction may play an important role in AD. However, additional critical questions need to be answered to better understand how astrocytic Slc1a2 may interact with A42 and tau pathology. Specifically, is there pathogenic synergy among these processes? In AD more needs to be uncovered about the relationship between neurons and the fine (often GFAP-negative) astrocytic processes expressing nearly all Slc1a2 in the brain—an anatomical relationship that is crucial to their function. In addition, there is insufficient data supporting the hypothesis that astrocytic Slc1a2 can play a contributing or causal role in exacerbating A42 and tau pathology. The goal of this project is to fill these knowledge gaps. First, we will use novel mice with reduced Slc1a2 specifically in astrocytes; and with adenoviral vectors (AAVs) expressing A42 and tauP301L, dissect the in vivo molecular interactions between these pathogenic pathways. We will address whether astrocytes are lost in response to A42 and/or tau. We will use a novel lentivirus system expressing Slc1a2, which infects astrocytes, to test whether specifically rescuing astrocytic Slc1a2 ameliorates neuropathology, as well as Slc1a2 function. Second, using state-of-the art patch clamp methods that directly measure astrocyte glutamate clearance, dissect how Slc1a2 loss, A42, and tau expression interact to affect astrocytic glutamate clearance. We will address how these pathogenic processes influence astrocytic Slc1a2 that regulate synaptic network excitability by supporting GABAergic transmission. Third, using well-characterized postmortem brains from control, prodromal, and AD patients we will test the potential translational significance of the glutamate transporter and astrocyte neuropathology we have reported and is suggested by our new preliminary data. Together, these data hold promise of advancing our knowledge of Slc1a2 as a potential molecular target for intervention in AD.

星形胶质细胞处于理想位置，可以支持神经元/突触对营养因子、代谢因子的需求 虽然反应性星形胶质细胞增多症是 AD 的一个显着特征，但它提供了体内平衡和免受毒性的保护。 关于星形胶质细胞如何影响疾病过程或它们如何受到伤害的了解非常有限。 星形胶质细胞最重要的功能之一是清除细胞外谷氨酸以防止兴奋性毒性。 星形胶质细胞吸收的谷氨酸也用作其他神经元生物合成的代谢底物。 因此，星形细胞谷氨酸清除至少有两种主要方式来保护 在大脑皮层和海马体中，谷氨酸转运蛋白 Slc1a2（也称为 GLT1 或 EAAT2）发挥着重要作用。 大多数（但不是全部）Slc1a2 在星形胶质细胞中发挥着最重要的作用。 我们的研究团队表明：(i) AD 小鼠模型中 Slc1a2 受到干扰；(ii) AD 小鼠模型中 Slc1a2 缺失 加速认知障碍的发生；(iii) A42 减缓海马突触释放的谷氨酸吸收 脑切片；(iv) 星形胶质细胞 Slc1a2 减少的小鼠表现出与 AD 显着的转录组重叠。 这些数据补充了其他小组的有力工作，并共同认为 Slc1a2 功能障碍可能 然而，为了更好地理解，还需要回答其他关键问题。 星形细胞 Slc1a2 如何与 A42 和 tau 病理学相互作用，具体来说，是否存在致病协同作用。 在AD中，需要更多地揭示神经元和神经元之间的关系？ 精细（通常 GFAP 阴性）星形胶质细胞过程表达大脑中几乎所有的 Slc1a2——解剖学上的 此外，没有足够的数据支持这一假设。 星形细胞 Slc1a2 可能在加剧 A42 和 tau 病理学方面发挥促进或因果作用。 该项目的目标是填补这些知识空白，首先，我们将使用 Slc1a2 减少的新型小鼠。 特别是在星形胶质细胞中；并使用表达 A42 和 tauP301L 的腺病毒载体 (AAV)，解剖 我们将探讨这些致病途径之间的体内分子相互作用。 对 A42 和/或 tau 的反应我们将使用表达 Slc1a2 的新型慢病毒系统，该系统会感染星形胶质细胞， 测试特异性拯救星形细胞 Slc1a2 是否可以改善神经病理学以及 Slc1a2 功能。 其次，使用最先进的膜片钳方法直接测量星形胶质细胞谷氨酸清除率， 我们将剖析 Slc1a2 缺失、A42 和 tau 表达如何相互作用影响星形胶质细胞的谷氨酸清除。 解决这些致病过程如何影响调节突触网络兴奋性的星形胶质细胞 Slc1a2 第三，使用经过充分表征的死后大脑进行控制， 对于前驱期和 AD 患者，我们将测试谷氨酸转运蛋白的潜在翻译意义和 我们已经报道了星形胶质细胞神经病理学，并由我们的新初步数据得出结论。 数据有望增进我们对 Slc1a2 作为干预 AD 的潜在分子靶点的了解。