Function of profilins in the tripartite synapse- from structural plasticity to functional modulation

三方突触中的profilin功能——从结构可塑性到功能调节

• 批准号: 320128407
• 负责人: Professor Dr. Martin Korte
• 金额: --
• 依托单位: Abteilung Zelluläre Neurobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/320128407?language=en
• 关键词: Function; profilins; tripartite; synapse; structural

For a long time cell biologists have been motivated to understand how the process of cellular self-organization generates dynamic, robust and elaborate structures that organize cells. In particular there is a fundamental gap between our understanding of individual molecules and our understanding of how these molecules function collectively to form living neurons. The biological importance of establishing order over diverse length scales and timescales, as well as the challenges of understanding how systems of self-organizing molecules carry out cellular functions, is perhaps best illustrated by studies of the cytoskeleton. And here the actin cytoskeleton is of upmost important. It is crucially involved in motility in all animal cells and particular in neurons and astrocytes, where it is mandatory in processes of motility. Neurons react to different activity levels with structural changes e.g. neuronal differentiation, dendritic and axonal maintenance and plastic adaption of dendrites, axons and synapses. Modulators of the microfilament system mediate signals from the pre- or postsynaptic membrane to the actin cytoskeleton and by this means change function and structure of specific neuronal compartments. In this context the actin binding protein profilin could be a mayor player. In the central nervous system, two isoforms of profilin, PFN 1 and PFN 2a, are co-expressed. Recent studies focusing on the cellular role of profilin 1 and 2a in neurons and glia cells are showing that both isoforms possess overlapping as well as isoform specific functions. Furthermore, the findings obtained by knocking out only one of the isoforms could not exclude that each isoform could compensate the loss of the other one. This hypothesis was supported via the acute downregulation of each isoform by RNA interference which leads to results that are not completely in line with the knock out studies. Therefore we will here address the functional role of profilins in astrocytes and in neurons by its acute inactivation. By this means we will study the formation and modulation of the tripartite synapse and thereby their impact on neuronal function. To avoid compensatory effects of each other profilin we will knock out both isoforms simultaneously in a cell-type specific manner by a CRISPR/Cas9 mediated approach. We will investigate the function of the profilin isoforms in the translation of neuronal activity into cytoskeletal reorganization, specifically in processes of structural and functional synaptic plasticity via modern imaging and electrophysiological methods. We will in addition use behavioral tests in order to explore the possible role of profilin isoforms in hippocampus dependent learning tasks.

长期以来，细胞生物学家一直致力于了解细胞自组织的过程如何产生动态，强大和精细的组织细胞的结构。特别是，我们对单个分子的理解与我们对这些分子如何共同作用形成活神经元的理解之间存在根本性的差距。在不同的长度尺度和时间尺度上建立秩序的生物学重要性，以及理解自组织分子系统如何执行细胞功能的挑战，也许最好的说明是细胞骨架的研究。在这里肌动蛋白细胞骨架是最重要的。它是至关重要的参与运动在所有动物细胞，特别是在神经元和星形胶质细胞，它是强制性的运动过程。神经元对不同的活动水平作出反应，并发生结构变化，例如神经元分化、树突和轴突维持以及树突、轴突和突触的可塑性适应。微丝系统的调节剂介导从突触前或突触后膜到肌动蛋白细胞骨架的信号，并通过这种方式改变特定神经元隔室的功能和结构。在这种情况下，肌动蛋白结合蛋白profilin可能是一个主要的球员。在中枢神经系统中，共表达两种profilin亚型PFN 1和PFN 2a。最近的研究集中在profilin 1和2a在神经元和神经胶质细胞中的细胞作用上，表明这两种亚型具有重叠以及亚型特异性功能。此外，仅敲除其中一种亚型所获得的发现不能排除每种亚型可以补偿另一种亚型的损失。通过RNA干扰对每种亚型的急性下调支持了这一假设，这导致了与敲除研究不完全一致的结果。因此，我们将在这里解决的功能作用的profilins在星形胶质细胞和神经元的急性失活。通过这种方法，我们将研究三方突触的形成和调制，从而对神经元功能的影响。为了避免每个其他profilin的补偿效应，我们将通过CRISPR/Cas9介导的方法以细胞类型特异性方式同时敲除两种亚型。我们将通过现代成像和电生理学方法研究profilin亚型在神经元活动转化为细胞骨架重组中的功能，特别是在结构和功能突触可塑性过程中的功能。此外，我们将使用行为测试，以探讨可能的作用，profilin异构体在海马依赖性学习任务。