Characterizing age-related decline of neural circuits by single-cell profiling

项目摘要/摘要 神经系统的功能依赖于适当的神经回路组装和长期的维护 电路的完整性。利用集成的单细胞基因组学方法，我建议在这里研究细胞 以及发育组装和年龄诱导的神经回路衰退的分子机制 果蝇嗅觉系统。 在果蝇嗅觉回路中，有50类嗅觉感受器神经元(Ons；每类 表达一种独特的嗅觉感受器)与50类嗅觉投射神经元精确连接， 为研究神经元连接的特异性提供了有力的模型。单细胞图谱分析方法(RNA-seq和 ATAC-SEQ)正在成为研究众多生物学问题的有力手段，包括 神经发育[22-27]。最近，我为果蝇开发了第一个单细胞rna-seq方案。 神经元(Li等人，2017年细胞)[25]。在这里，我想应用单细胞分析方法来1)对ORN进行分类 分类，2)识别连接特异性基因，3)探索协调嗅觉受体的机制 表达和ORN连接特异性(目标1和2；主要在K99训练阶段)。 嗅觉敏感度的丧失是衰老和神经退行性疾病的首批迹象之一，例如 果蝇的嗅觉敏感度也随着年龄的增长而显著下降。在这里，我提出一个 果蝇年龄相关性嗅觉衰退的细胞和分子机制研究。 我们的实验室最近发现，胶质细胞对调节苍蝇嗅觉回路的组装至关重要[8]。 大量研究表明，在许多情况下，神经胶质细胞与神经元的相互作用对大脑功能很重要。 神经系统[9-11]。综上所述，我假设神经胶质细胞继续需要维持 嗅觉回路在一生中发挥作用，与年龄相关的神经胶质功能障碍有助于 老年果蝇的嗅觉衰退。我想将单细胞图谱技术与遗传方法结合起来进行测试 这一假设(目标3；主要针对R00独立期)。 我的导师团队由世界著名神经学家罗立群博士(导师)和罗立群博士组成。 霍华德·张(共同导师)和斯蒂芬·奎克(合作者)，两位单细胞基因组学的领军人物 和表观基因组学，以及衰老和神经退行性变专家Tony Wyss-Coray博士(顾问)， 马克·弗里曼博士(咨询师)，果蝇神经胶质的专家。在他们的指导下，我相信我会收获 在我的转型过程中，我接受了广泛的培训，成为一名独立的PI。

Project Summary/Abstract The function of the nerves system relies on appropriate neural circuit assembly and long-term maintenance of the circuit integrity. Employing integrated single-cell genomic approaches, here I propose to investigate cellular and molecular mechanisms of developmental assembly and age-induced decline of neural circuits using the Drosophila olfactory system. In the Drosophila olfactory circuit, 50 classes of olfactory receptor neurons (ORNs; each class expresses a unique olfactory receptor) connect precisely with 50 classes of olfactory projection neurons, providing a powerful model to study the neuronal wiring specificity. Single-cell profiling methods (RNA-seq and ATAC-seq) are emerging as powerful approaches to study numerous biological questions, including neurodevelopment [22-27]. Recently, I have developed the first single-cell RNA-seq protocol for Drosophila neurons (Li et al., 2017 Cell) [25]. Here, I would like to apply single-cell profiling approaches to 1) classify ORN classes, 2) identify wiring specificity genes, and 3) explore mechanisms that coordinate olfactory receptor expression and ORN wiring specificity (Aims 1&2; mainly on K99 training phase). Loss of olfactory sensitivity is among the first signs of aging and neurodegenerative diseases, such as Alzheimer's. In Drosophila, the olfactory sensitivity also significantly declines with age. Here, I propose a mechanistic study to identify cellular and molecular mechanisms for age-related olfactory decline in Drosophila. Our lab has recently found that glia cells are critical for regulating the assembly of the fly olfactory circuit [8]. Numerous studies have shown that the glia-neuron interactions are important for the brain function in many neuronal systems [9-11]. Together, I hypothesize that glial cells continue to be required for maintaining the olfactory circuit function throughout the life, and that age-associated glial dysfunction contributes to the olfactory decline in old flies. I would like to combine single-cell profiling techniques with genetic methods to test this hypothesis (Aim 3; mainly on R00 independent phase). My mentoring team consists of Dr. Liqun Luo (mentor), a world-renowned neuroscientist, and Drs. Howard Chang (co-mentor) and Stephen Quake (collaborator), two leading scientists in single-cell genomics and epigenomics, as well as Dr. Tony Wyss-Coray (consultant), an expert on aging and neurodegeneration, and Dr. Marc Freeman (consultant), an expert on Drosophila glia. With their guidance, I believe that I will gain extensive training in my transition to be an independent PI.