Impact of changes in nuclear calcium signaling triggered by atlastin mutations and ER structural alterations on gene regulation and neuronal functions.

神经系统中大多数与可塑性相关的过程，包括学习和记忆，都依赖于钙信号。由突触活动诱导的钙瞬变刺激钙进入胞质溶胶的位点附近的局部信号传导事件。然而，钙升高也可以扩散到整个神经元，并将信号传递到细胞核，导致基因转录的激活或抑制。神经元内质网（ER）在细胞内钙离子转运中起着重要作用。然而，目前尚不清楚ER的形态特征是否以及如何影响钙瞬变和钙依赖性功能的空间方面和动力学，特别是细胞核中的那些。近年来已经描述了许多不同的蛋白质，它们用于塑造ER结构。微管弯曲的网状蛋白和微管融合的GTatlastins（ATLs）代表了两组在ER形态的发展和维持中的关键参与者，并与人类神经退行性疾病有关。本项目的目的是研究内质网结构的改变对突触活动诱导的核钙信号传导、基因表达和神经元功能的影响。我们将使用ER成形ATLs家族的功能丧失突变以及海马神经元中的RNA干扰来改变ER形态，并研究其对核钙驱动基因激活的后果，这些基因已知对巩固神经适应和神经元存活至关重要。体外研究将集中在获得性神经保护，突触活动和核钙依赖形式的增强生存活动。体内研究将使用立体定向递送至小鼠海马体的重组腺相关病毒，所述重组腺相关病毒含有GTP酶失活的显性负性ATL或靶向特异性atlastins的shRNA的表达盒，以确定ER形态对学习相关基因表达和海马体依赖性记忆巩固的贡献。

Most plasticity-related processes in the nervous system, including learning and memory rely on calcium signaling. Calcium transients induced by synaptic activity stimulate local signaling events in the vicinity of the site of calcium entry into the cytosol. However, calcium rises can also spread throughout the neuron and convey signals to the cell nucleus leading to activation or repression of gene transcription. The neuronal endoplasmic reticulum (ER) plays an important role in cellular calcium handling. However, it is unknown if and how the morphological features of the ER impact on the spatial aspects and dynamics of calcium transients and calcium-dependent functions, in particular those in the cell nucleus. Many different proteins have been described in recent years that serve to shape the ER architecture. The tubule curving reticulons and the tubule fussing GTPase atlastins (ATLs) represent two groups of key players in the development and maintenance of ER morphology and have been implicated in human neurodegenerative diseases. The goal of this project is to investigate the impact of structural alteration of ER architecture on synaptic activity induced nuclear calcium signaling, gene expression, and neuronal functions. We will use loss-of–function mutations of the ER-shaping family of ATLs as well as RNA interferences in hippocampal neurons to alter ER morphology and study the consequences of it for the activation of nuclear calcium-driven genes that are known to be important for the consolidation of neuroadaptations and neuronal survival. In vitro studies will be focused on acquired neuroprotection, a synaptic activity- and nuclear calcium-dependent form of enhanced survival activity. In vivo studies will use stereotactic delivery to the mouse hippocampus of recombinant adeno associated viruses containing expression cassettes for GTPase-inactive, dominant negative ATLs or shRNAs targeting specific atlastins to determine the contribution of ER morphology to learning associated gene expression and hippocampus-dependent memory consolidation.