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)，并为新陈代谢提供支持 神经元活动。在阿尔茨海默病(AD)中，星形胶质细胞在斑块附近变得活跃，有助于 神经炎症，并导致突触和回路异常。星形胶质细胞在其中发挥的作用 在AD中，通过从细胞外空间移除谷氨酸来控制突触兴奋尤其耐人寻味。 星形胶质细胞高水平表达兴奋性氨基酸转运体，包括GLT1和GLAST 它们的外周突起结合和移除细胞外的谷氨酸，以限制突触的兴奋。东亚航空运输协会，AS 和其他星形细胞蛋白一样，已知在AD进展的后期会减少。谷氨酸信号异常 被认为是促进AD进展的因素，临床使用谷氨酸受体美金刚证明了这一点 拮抗剂作为AD的一种治疗方法，强烈地提示EAATs参与了AD的进展。最后，可溶性A抑制 EAAT在神经元活动增强过程中的作用。有趣的是，我们最近发现神经元活动 引起星形胶质细胞去极化，从而促使对EAAT功能的电压依赖性抑制增强 神经元激活。在亲本R01中，我们使用星形胶质细胞表达的遗传编码电压指示器 (GEVI)对VM进行光学量化，并显示神经元活动使外周星形胶质细胞突起去极化 (PAPs)，具有突触特异性。在本补充请求中，我们提供了在正常老化期间的初步数据 星形胶质细胞零星丢失GLT1、GLAST和Kir4.1的表达，并呈现一种称为 非典型星形胶质细胞(ATA)。重要的是，ATAS不是反应性星形细胞增多症的一种形式。初步数据显示 在阿尔茨海默病APPNL-G-F小鼠模型中，ATA含量更丰富，发生得更早，在老年人中也可见 大脑。在这里，我们将检验他们的假设，因为缺少Kir4.1和GLT-1的atas在 在APPNL-G-F小鼠的海马区，星形胶质细胞经历了活动诱导的去极化增加，导致 对谷氨酸摄取的夸大抑制。这创造了一种情况，在这种情况下，神经元活动增加可能 驱动协同电压依赖和A-介导的阿尔茨海默病的抑制作用。我们选择使用APPNL-G-F 模型因起病早，与正常的ATAS发展重叠，无APP过度表达。 利用APPNL-G-F小鼠，我们将确定：(SA1)APPNL-G-F小鼠的海马星形胶质细胞是否表现出增加 VM对神经元活动的反应？“和(SA2)“是否增强了谷氨酸摄取的活性依赖性抑制作用 APPNL-G-F小鼠的海马区？“。活动诱发的PAP去极化增加和A升高均可 改变活性诱导的APPNL-G-F小鼠EAAT抑制。如果是这样的话，这将定位星形胶质细胞与神经元的相互作用， K+和谷氨酸稳态在早期AD进展中的关键作用，并将促进谷氨酸的增加 K+摄取减少AD相关病理改变。完成后，我们将知道新发现的更改是否 在PAP中，Vm被夸大，并导致APPNL-G-F小鼠异常的谷氨酸兴奋。我们会做好准备 利用这些发现来增强K+和谷氨酸的动态平衡，以防止AD的病理性兴奋。