Identifying the insulin-signaling targets that regulate synapse development

我们的神经系统需要产生和维持功能性神经元和神经元-肌肉连接。利用线虫这一小型动物模型，我们发现，胰岛素信号的减弱不仅恢复了神经肌肉连接发育缺陷的遗传突变体的神经元-肌肉连接(称为神经肌肉连接)的形态和功能，而且在神经退行性变的动物模型中也起到了很强的保护作用。有趣的是，胰岛素信号的发育和神经保护作用都涉及神经系统的胰岛素分泌和肌肉细胞中信号级联的激活，这两种作用都严格依赖于肌肉中一种名为DAF-16的转录因子的存在。因此，识别肌肉特异的DAF-16转录靶点对于理解和生物医学应用胰岛素信号的发育和保护作用至关重要。*我们项目的目标是确定DAF-16的转录靶点。具体地说，我们将首先利用线虫模型来确定其在肌肉细胞中的表达被DAF-16特异性激活或抑制的基因，并进行功能分析以确定那些对动物维持强大的神经肌肉连接形态和功能至关重要的基因。一旦确定了这些靶点，我们将通过检测它们是否影响线虫神经退变模型中的神经肌肉连接表型和功能，以及它们是否具有使用人类iPS细胞衍生的体外神经肌肉系统的功能保护来进一步检验它们的生物医学影响。*****

Our nervous system needs to generate and maintain functional neuronal and neuron-muscle connections. Using C. elegans, a small animal model, we discovered that an attenuation of insulin signalling not only restores the morphology and function of the neuron-muscle connection (called neuromuscular junctions) in genetic mutants with defective neuromuscular junction developments, but also exerts strong protection in animal models for neurodegeneration. Intriguingly, both the developmental and neural protective role of insulin signalling involves secretion of insulin from the nervous system, and the activation of a signalling cascade in the muscle cells, and both roles strictly depend on the presence of a transcription factor called DAF-16 in muscles. Hence, identification of muscle-specific DAF-16 transcriptional targets becomes critical for an understanding and biomedical application of the developmental and protective roles of insulin signalling. ******The goal of our project is to identify the DAF-16 transcriptional targets. Specifically, we will first utilize the C. elegans model to identify genes whose expression is specifically activated or repressed by DAF-16 in muscle cells, and perform functional assay to identify those that are critical for animals to maintain robust neuromuscular junction morphology and function. Upon the identification of such targets, we will further examine their biomedical impact by examining whether they affect the neuromuscular junction phenotype and function in the C. elegans neurodegenerative models, and whether they have functional conservation using a human iPS cell-derived in vitro neuromuscular system. *****