Enhancing induced neurogenesis in the damaged mouse cerebral cortex by activation of local microcircuits

在过去的十年里，我们和其他人已经证明了通过直接谱系重编程将脑实质胶质细胞转化为缺乏典型成人神经发生的大脑区域中的诱导神经元的可行性。我们最近发现，皮质损伤促进神经原性转录因子Sox 2和Ascl 1的强制表达后，神经胶质细胞转化为神经元。然而，未知的机制阻止了这些诱导神经元的成熟，使其具有完整的功能和适当的网络整合。Schinder博士的实验室最近表明，在成人大脑的典型神经原性小生境中，如海马齿状回，新产生的神经元的功能整合大大促进了宿主微电路的电活动。该项目结合了两个小组的研究结果和专业知识，旨在研究电活动对受损成人大脑皮层中诱导神经元的发育和整合的影响，从而优化未来大脑修复的策略。在这里，我们假设来自谱系重编程胶质细胞的神经元的成熟和功能整合遵循与内源性产生的神经元类似的逻辑，因此电活动将在促进其形态功能发育和最终适当连接到预先存在的网络中发挥关键作用。为此，我们将利用最先进的技术在体内操纵局部皮层微电路的活动。我们将结合联合收割机不同的病毒载体系统（逆转录病毒，腺相关病毒，狂犬病病毒）和转基因小鼠与光和化学遗传学在体内和体外。这将使我们能够选择性地操纵大脑皮层内的特定回路组件，例如锥体神经元与小清蛋白阳性中间神经元，并研究诱导神经元的解剖和功能特性。虽然最初每个实验室将提供不同的实验方法和努力，但拟议的项目将强调交流专门知识，以便培训人力资源，使两组的能力相等。

During the last decade we and others have demonstrated the feasibility of converting parenchymal glia into induced neurons in brain regions devoid of canonical adult neurogenesis via direct lineage reprogramming. We recently discovered that cortical damage faciliates the conversion of glia into neurons upon forced expression of the neurogenic transcription factors Sox2 and Ascl1. Yet, unknown mechanisms prevent the maturation of these induced neurons towards complete functionality and proper network integration. The laboratory of Dr. Schinder has recently shown that functional integration of newly generated neurons in a canonical neurogenic niche of the adult brain such as the dentate gyrus of the hippocampus is greatly facilitated by electrical activity of the host microcircuits. This project combines the findings and expertise of both groups with the aim of investigating the effects of electrical activity on the development and integration of induced neurons in the damaged adult cerebral cortex and thereby optimizing strategies for future brain repair. Here we hypothesize that the maturation and functional integration of neurons derived from lineage reprogrammed glia follows a similar logic as that of endogenously generated neurons, and that therefore electrical activity will play a pivotal role in promoting their morphofunctional development and ultimately appropriate connectivity into the pre-existing network. To this end, we will utilize state-of-the-art technologies for manipulating in vivo the activity of local cortical microcircuits. We will combine different viral vector systems (retroviruses, adenoassociated viruses, rabies virus) and genetically modified mice with opto- and chemogenetics in vivo and ex vivo. This will allow us to manipulate selectively specific circuit components within the cerebral cortex, such as pyramidal neurons versus parvalbumin-positive interneurons, and to study the resulting anatomical and functional properties of induced neurons. Although initially each laboratory will contribute different experimental approaches and exertise, the proposed project will emphasize the exchange of know-how to allow for training of human resources to equalize the capacities of both groups.