Deciphering the mRNP Code for Successful Glia to Neuron Reprogramming

新神经元的产生及其功能整合到受损的神经元回路中是脑损伤和神经变性再生医学的主要挑战。最近，一种革命性的方法将局部反应性胶质细胞在神经原性因子的帮助下转化为功能整合的神经元，这是恢复神经元回路的一个里程碑。由于转化率惊人地高，这种方法对未来的再生疗法最有希望。然而，为了将这些革命性的发现转化为临床应用，还必须解决一些障碍，包括新神经元与原有神经回路的突触整合。我们最近发现，胶质细胞向神经元的直接转化需要RNA结合蛋白（RBP）Staufen2（Stau2）和Pumilio2（Pum2）。此外，我们发现，Stau2结合两个关键的RNA编码的Hes1和Sox11，都代表关键的神经元转录？胶质细胞直接转化为神经元所必需的因素。因此，我们将研究Stau2和Pum2在实现神经元命运的功能，通过确定直接星形胶质细胞向神经元转化所必需的一组基本RNA靶标。接下来，我们将剖析这些RBP在控制神经源性靶RNA稳定性，定位和局部翻译过程中的作用。此外，我们将解决命运决定中Stau 2和Pum 2功能的特异性（和冗余）。最后，我们将确定参与Hes 1和Sox 11 mRNAs功能调节的其他关键RBP，以详细了解mRNP组装的动力学及其对直接胶质细胞向神经元转化的功能贡献。我们设想，本提案中概述的实验将使我们能够启动新的策略，以改善新神经元向受损回路的功能整合，从而探索其潜在的神经功能。再生疗法

The generation of new neurons and their functional integration into damaged neuronal circuits are the major challenges in regenerative medicine upon brain injury and neurodegeneration. A recent, revolutionary approach to convert local, reactive glial cells with the help of neurogenic factors into functionally integrated neurons represented a milestone in restoring neuronal circuitry. As conversion works at surprisingly high rates, this approach is most promising for future regenerative therapies. However, a number of obstacles, including the synaptic integration of new neurons into the pre-existing circuitry, have to be resolved in order to translate these revolutionary discoveries into the clinic.We have recently discovered that the direct conversion of glial cells to neurons requires the RNA-binding proteins (RBPs) Staufen2 (Stau2) and Pumilio2 (Pum2). Moreover, we showed that Stau2 binds two key RNAs coding for Hes1 and Sox11, both representing key neuronal transcription? factors essential for direct glia to neuron conversion. Therefore, we will investigate Stau2 and Pum2 function in implementing neuronal fate by identifying the essential set of RNA targets necessary for direct astrocyte to neuron conversion. Next, we will dissect the role of these RBPs in controlling neurogenic target RNA stability, localization and local translation during the conversion process. Moreover, we will address the specificity (and redundancy) in Stau2 and Pum2 function(s) in fate decision. Finally, we will identify additional key RBPs involved in the functional regulation of Hes1 and Sox11 mRNAs in order to understand the dynamics of mRNP assembly and their functional contribution to direct glia to neuron conversion in detail.We envision that the experiments outlined in this proposal will enable us to initiate novel strategies to improve functional integration of new neurons into damaged circuits and hence explore their potential for regenerative therapies.