Voltage Imaging of Astrocyte-Neuron Interactions

星形胶质细胞-神经元相互作用的电压成像

• 批准号: 10711423
• 负责人: Chris G Dulla
• 金额: $ 41.25万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10711423
• 关键词: Acceleration; Action Potentials; Affect; Age Months; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease therapy; Amino Acid Transporter; Anatomy; Astrocytes; Astrocytosis; Binding; Blood - brain barrier anatomy; Brain; Cessation of life; Clinical; Data; Development; Disease; Disease Progression; Excitatory Amino Acid Antagonists; Excitatory Amino Acids; Extracellular Space; Functional disorder; GLAST Protein; Glutamates; Heterozygote; Hippocampus; Homeostasis; Human; Image; Mediating; Memantine; Metabolic; Modeling; Mus; Neurons; Optics; Parents; Pathologic; Pathology; Peripheral; Phenotype; Play; Population; Positioning Attribute; Potassium; Potassium Channel; Process; Proteins; Role; Seizures; Shapes; Specificity; Synapses; Testing; Time; aged; disease phenotype; early onset; excitotoxicity; experience; extracellular; glutamatergic signaling; mouse model; neuroinflammation; neurotransmission; normal aging; overexpression; prevent; response; uptake; voltage

ABSTRACT. Astrocytes control neurotransmission, contribute to a robust blood-brain-barrier (BBB), and metabolically support neuronal activity. In Alzheimer’s Disease (AD), astrocytes become reactive near A plaques, contribute to neuroinflammation, and contribute to synaptic and circuit abnormalities. The role that astrocytes play in controlling synaptic excitation by removing glutamate from the extracellular space is particularly intriguing in AD. Astrocytes express high levels of excitatory amino acid transporters (EAATs), including GLT1 and GLAST, in their peripheral processes that bind and remove extracellular glutamate to limit synaptic excitation. EAATs, as well as other astrocyte proteins, are known to be decreased late in AD progression. Aberrant glutamate signaling is thought to contribute to AD progression, as evidenced by the clinical use of memantine, a glutamate receptor antagonist, as an AD therapy, strongly implicating EAATs in the progression of AD. Finally, soluble A inhibits EAAT function during heightened neuronal activity. Interestingly, we recently showed that neuronal activity causes astrocyte depolarization, which drives voltage-dependent inhibition of EAAT function to enhance neuronal activation. In the parent R01, we use astrocyte-expressed genetically encoded voltage indicators (GEVIs) to optically quantify Vm and showed that neuronal activity depolarizes peripheral astrocyte processes (PAPs) with synapse-specificity. In this supplement request, we provide preliminary data that during normal aging astrocytes sporadically lose the expression of GLT1, GLAST, and Kir4.1 and take on a phenotype known as atypical astrocytes (AtAs). Importantly, AtAs are not a form of reactive astrocytosis. Preliminary data suggests AtAs are more abundant and occur earlier in the APPNL-G-F mouse model of AD and are seen in the aged human brain. Here we will test they hypothesis that because AtAs, which lack Kir4.1 and GLT-1, are abundant in the hippocampus of APPNL-G-F mice, astrocytes experience increased activity-induced depolarization, leading to exaggerated inhibition of glutamate uptake. This creates a situation in which increased neuronal activity could drive synergistic voltage-dependent and A-mediated EAAT inhibition in AD. We chose to use the APPNL-G-F model due to its early onset, overlapping with the normal development of AtAs, without APP overexpression. Using the APPNL-G-F mice, we will determine: (SA1) “Do hippocampal astrocytes in APPNL-G-F mice show increased Vm responses to neuronal activity?” and (SA2) “Is activity-dependent inhibition of glutamate uptake enhanced in the hippocampus of APPNL-G-F mice?“. Both increased activity-induced PAP depolarization and elevated A could alter activity-induced EAAT inhibition in APPNL-G-F mice. If so, this would position astrocyte-neuron interactions, K+ and glutamate homeostasis as key players in early AD progression and would motivate enhancing glutamate and K+ uptake to reduce AD-related pathology. When complete, we will know whether newly discovered changes in PAP Vm are exaggerated and contribute to aberrant glutamate excitation in APPNL-G-F mice. We will be poised to leverage these findings to enhance K+ and glutamate homeostasis to prevent pathological excitation in AD.

抽象的。 星形胶质细胞控制神经传递，有助于强大的血脑屏障（BBB），并在代谢中支持 神经元活性。在阿尔茨海默氏病（AD）中，星形胶质细胞在A斑块附近变得反应性，有助于 神经炎症，并导致突触和电路异常。星形胶质细胞在 通过从细胞外空间中去除谷氨酸来控制突触兴奋，在AD中特别有趣。 星形胶质细胞表达高水平的兴奋性氨基酸转运蛋白（EAATS），包括GLT1和GLAST，在 它们结合并去除细胞外谷氨酸以限制合成兴奋的外围过程。 eaats，as 以及其他星形胶质细胞蛋白，已知在AD进展中得到改善。异常的谷氨酸信号传导 被认为有助于AD进展，正如美金刚（Memantine）谷氨酸接收器的临床使用所证明的那样 作为AD疗法的拮抗剂，在AD的发展中强烈隐含了Eaats。最后，可溶性抑制 EAAT功能增强神经元活性。有趣的是，我们最近表明神经元活动 导致星形胶质细胞沉积，从而驱动电压依赖性抑制EAAT功能以增强 神经元激活。在父R01中，我们使用星形胶质细胞表达的一般编码电压指示器 （GEVI）光学量化VM，并表明神经元活性去极化外周星形胶质细胞过程 （PAPS）具有突触特异性。在此补充要求中，我们提供了在正常老化期间的初步数据 星形胶质细胞偶尔失去GLT1，Glast和Kir4.1的表达，并采用一种称为表型 非典型星形胶质细胞（ATA）。重要的是，ATA不是反应性星形细胞增多症的一种形式。初步数据建议 ATA更丰富，并且发生在Appnl-g-f小鼠AD模型中，并在老年人中看到 脑。在这里，我们将测试他们的假设，因为缺乏Kir4.1和GLT-1的ATA在 AppNL-G-F小鼠的海马，星形胶质细胞的经历增加了活性引起的沉积，导致 夸大谷氨酸摄取的抑制作用。这会产生一种情况，在这种情况下，神经元活动可能 驱动AD中的协同电压依赖性和A介导的EAAT抑制作用。我们选择使用appnl-g-f 模型由于其早期发作，与ATA的正常开发重叠，而无需APP过表达。 使用AppNL-G-F小鼠，我们将确定：（SA1）“ Appnl-G-F小鼠中的海马星形胶质细胞显示出增加 VM对神经元活动的反应？” （sa2）“是活性依赖性抑制谷氨酸摄取的抑制 Appnl-G-F小鼠的海马？ 改变活动引起的APPNL-G-F小鼠中的EAAT抑制作用。如果是这样，这将使星形胶质细胞神经元相互作用， K+和谷氨酸稳态作为早期广告进展的关键参与者，并会激励谷氨酸 和K+摄取以减少与广告相关的病理。完成后，我们将知道新发现的更改是否 在PAP VM中，VM被夸大，并导致AppNL-G-F小鼠中异常的谷氨酸兴奋。我们会中毒 利用这些发现来增强K+和谷氨酸稳态，以防止AD中的病理兴奋。