Dynamic temporal regulation of astrocyte coupling to shape neuronal activity during acquired epilepsy development

获得性癫痫发展过程中星形胶质细胞耦合塑造神经元活动的动态时间调节

• 批准号: 10366826
• 负责人: Stefanie Robel
• 金额: $ 34.63万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-15 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10366826
• 关键词: Affect; Antiepileptic Agents; Astrocytes; Cells; Chemicals; Chronic; Connexin 43; Connexins; Consensus; Coupling; Data; Development; Disease; Drug Targeting; Electroencephalography; Electrophysiology (science); Epilepsy; Foundations; Functional disorder; Future; Gap Junctions; Impairment; In Situ; Intractable Epilepsy; Knock-in Mouse; Knockout Mice; Measurement; Measures; Modeling; Monitor; Mus; Mutate; Mutation; Neurologic; Neurons; Pathology; Patients; Persons; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiology; Positioning Attribute; Post-Translational Protein Processing; Process; Proteins; Regulation; Seizures; Serine; Shapes; Signal Pathway; Signal Transduction; Silicon; Techniques; Technology; Testing; Time; Traumatic Brain Injury; Viral; Virus; Western Blotting; acquired epilepsy; in vivo; mild traumatic brain injury; mimetics; mouse model; mutant; prevent; research and development; therapeutic target; tool

Project Summary Astrocytes couple into networks of hundreds of cells. Impaired astrocyte coupling is associated with epilepsy, but there is no consensus on whether reduced coupling promotes or counteracts abnormal neuronal activity, which precedes seizures. A lack of astrocyte coupling can promote seizures;1 yet, the opposite has also been shown: abnormal neuronal activity and seizures were reduced after coupling was inhibited1-3. An integrated view that accounts for both findings is needed to reveal how astrocyte coupling modulates epilepsy. In acquired epilepsy, which is initiated by a neurological insult such as traumatic brain injury (TBI), many studies have demonstrated dysfunction of gap junctions (GJs) and dysregulation of Connexin43 (Cx43). Cx43 forms GJ responsible for astrocyte coupling leading to the conclusion that reduced coupling may contribute to seizures. Studies in Cx43 knockout mice suggest that the timing and duration of reduced astrocyte coupling may determine if abnormal neuronal activity is promoted or counteracted. This has not been tested due to a lack of tools that dynamically modulate coupling. To reduce or restore astrocyte coupling dynamically, we generated viral constructs that can be induced to express functional or mutated Cx43 for variable durations at different stages of acquired epilepsy. These Cx43 mutants inhibited astrocyte coupling and induced neuronal hyperexcitability in vivo. To assess the relationship between astrocyte coupling and neuronal activity, we will use a model of acquired epilepsy that progresses to spontaneous seizures after mild TBI in the absence of many confounding factors5. This model recapitulates three key aspects of Cx43 pathology: astrocyte coupling is reduced, Cx43 protein is increased and increased phosphorylation at Cx43 serine 368. This post-translational modification alters GJ conductivity, and is associated with internalization of GJ. Yet, the critical upstream signaling causing reduced astrocyte coupling and its effects on neuronal activity during different stages of acquired epilepsy must be revealed as a foundation for future therapeutic targeting. This proposal will generate an integrated model of astrocyte coupling modulation in acquired epilepsy that aims to unify previous findings. Cx43 function will be dynamically manipulated to 1) determine if the timing of reduced astrocyte coupling modulates abnormal neuronal activity 2) identify the signaling cascade controlling reduced astrocyte coupling and 3) determine if and when restoring astrocyte coupling prevents acquired epilepsy. Acquired epilepsy affects 65 million people worldwide and is notoriously difficult to treat. Even after decades of research and the development of new anti-epileptic drugs targeting neurons, one third of patients still suffer from drug-resistant epilepsy. Targeting astrocytic Cx43 might be an option, but the first step towards therapy is determining when reduced coupling is adaptive and when it is maladaptive.

项目摘要 星形胶质细胞夫妇进入数百个细胞的网络。星形胶质细胞耦合受损与 癫痫病，但尚未达成共识 活动，先于癫痫发作。缺乏星形胶质细胞耦合可以促进癫痫发作； 1然而，相反的情况也相反 显示了：抑制耦合后1-3后，神经元活性异常和癫痫发作降低。一个 需要进行两种发现的综合观点，以揭示星形胶质细胞耦合如何调节癫痫。 在获得的癫痫中，这是由神经系统侮辱（例如创伤性脑损伤（TBI））引发的，许多 研究表明，间隙连接（GJS）和连接症的功能障碍（CX43）功能障碍。 CX43 负责星形胶质细胞耦合的GJ表格，得出的结论是，耦合减少可能有助于 癫痫发作。在CX43敲除小鼠中的研究表明，星形胶质细胞耦合减少的时间和持续时间可能 确定是否促进或抵消神经元活性异常。由于缺乏 动态调节耦合的工具。为了动态减少或恢复星形胶质细胞耦合，我们生成了 可以诱导在不同持续时间以不同持续时间表达功能性或突变CX43的病毒构建体 获得癫痫的阶段。这些CX43突变体抑制星形胶质细胞耦合并诱导神经元 体内过度兴奋。为了评估星形胶质细胞耦合与神经元活动之间的关系，我们将 使用一种获得的癫痫模型，该模型在没有许多的情况下轻度TBI后自发癫痫发作 混杂因素5。该模型概括了CX43病理学的三个关键方面：星形胶质细胞耦合是 降低，CX43蛋白增加并增加了CX43丝氨酸368的磷酸化。 修改会改变GJ电导率，并与GJ的内在化有关。但是，上游的关键 信号传导导致星形胶质细胞耦合及其对神经元活动的影响在不同阶段 获得的癫痫必须被揭示为未来治疗靶向的基础。该建议将产生 旨在统一先前发现的获得性癫痫中星形胶质细胞耦合调制的集成模型。 CX43功能将动态操纵至1）确定星形胶质细胞耦合的时间是否降低 调节神经元活性异常2）确定控制星形胶质细胞耦合减少的信号级联 3）确定是否以及恢复星形胶质细胞耦合是否可以防止获得的癫痫。获得的癫痫会影响 全世界有6500万人，众所周知，很难治疗。甚至经过数十年的研究和 开发针对神经元的新型抗癫痫药，三分之一的患者仍患有抗药性 癫痫。靶向星形胶质细胞CX43可能是一种选择，但是治疗的第一步是确定何时 减少的耦合是适应性的，并且是适应不良的。