Analyzing PKA-dependent synaptic plasticity in the hippocampal mossy fiber synapse using novel optogenetic tools

使用新型光遗传学工具分析海马苔藓纤维突触中 PKA 依赖性突触可塑性

• 批准号: 417451587
• 负责人: Professor Dr. Georg Nagel
• 金额: --
• 依托单位: Lehrstuhl für Physiologie II - Neurophysiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/417451587?language=en
• 关键词: Analyzing; PKA; dependent; synaptic; plasticity

Synaptic plasticity plays an important role in brain activity and is thought to be one of the main cellular processes underlying learning and memory. While in many synapses long-term potentiation is mediated by post-synaptic mechanisms, several synapses, most notably the hippocampal mossy fiber (MF), the cerebellar parallel fiber and Drosophila neuromuscular-junction synapses, exhibit presynaptic plasticity, which manifests as changes in the probability of synaptic vesicle release. Interestingly, this form of pre-synaptic plasticity depends on presynaptic activation of PKA in all the aforementioned synapses. The molecular mechanism underlying this PKA-dependent synaptic plasticity is still largely unknown. Currently, the control over PKA-activation levels is limited to adenylyl cyclase agonists, such as forskolin (FSK), or metabotropic glutamate receptor agonists. These treatments affect both pre- and post-synaptic neurons, as well as non-neuronal cell populations, their effect is not restricted to the synapse and is usually irreversible, facts that make these pharmacological agents less-than-ideal candidates to study synapse-specific effects of PKA activation. In light of this, the ability to manipulate PKA in the synapses of a genetically-identifiable subset of cells is highly instrumental in studying presynaptic PKA-dependent mechanisms. Accordingly, the current project aims are; a) develop, optimize and characterize novel optogenetic tools to control the level of PKA-activation in a synapse-specific manner b) investigate the effects of these novel optogenetic tools on synaptic transmission in the MF synapse, c) Examine if local pre- or post-synaptic PKA activation is sufficient to potentiate synaptic transmission, d) elucidate changes in the molecular organization of the AZ machinery following PKA activation, using super resolution microscopy and e) investigate the involvement of PKA downstream targets on synaptic potentiation. We will join forces, capitalizing on the expertise in the lab of Prof. Nagel in developing novel light activated PKA tools and combining this with the genetic and physiological approaches developed in Prof. Ashery’s lab to target and activate PKA only in MF and examine its effect on synaptic plasticity and the molecular mechanisms.

突触可塑性在大脑活动中发挥着重要作用，被认为是学习和记忆的主要细胞过程之一。虽然在许多突触中，长时程增强是由突触后机制介导的，但一些突触，尤其是海马苔藓纤维（MF）、小脑平行纤维和果蝇神经肌肉接头突触，表现出突触前可塑性，表现为突触小泡释放概率的变化。有趣的是，这种形式的突触前可塑性取决于所有上述突触中 PKA 的突触前激活。这种 PKA 依赖性突触可塑性的分子机制仍然很大程度上未知。目前，对 PKA 激活水平的控制仅限于腺苷酸环化酶激动剂，例如毛喉素 (FSK) 或代谢型谷氨酸受体激动剂。这些治疗会影响突触前和突触后神经元以及非神经元细胞群，其作用不仅限于突触，而且通常是不可逆的，这些事实使得这些药物制剂不太适合研究 PKA 激活的突触特异性作用。有鉴于此，在可遗传识别的细胞子集的突触中操纵 PKA 的能力对于研究突触前 PKA 依赖性机制非常有帮助。因此，当前项目的目标是： a) 开发、优化和表征新型光遗传学工具，以突触特异性方式控制 PKA 激活水平 b) 研究这些新型光遗传学工具对 MF 突触突触传递的影响，c) 检查局部突触前或突触后 PKA 激活是否足以增强突触传递，d) 使用超级方法阐明 PKA 激活后 AZ 机器分子组织的变化 分辨率显微镜和 e) 研究 PKA 下游靶标对突触增强的参与。我们将联手，利用 Nagel 教授实验室开发新型光激活 PKA 工具的专业知识，并将其与 Ashery 教授实验室开发的遗传和生理方法相结合，仅在 MF 中靶向和激活 PKA，并检查其对突触可塑性和分子机制的影响。