CAREER: Imaging Mechanisms of Dendritic Development in the Living Neuron

哺乳动物大脑中的神经细胞（神经元）通常具有精致的树状分支，这些分支是由被称为树突的精细细胞延伸而成的，它们接收来自其他神经元活动的化学信号。就像天线一样，树突上分支的位置和数量组织了传入输入的模式，因此决定何时何地形成分支是至关重要的。这些树突的细胞内结构包括称为肌动蛋白和微管的细胞骨架成分，这些成分是动态的，随着时间的推移，通过在特定点的分支的伸长或缩回或稳定来改变树突结构。目前尚不清楚在发育和生长过程中决定这些高度特异性乔木模式的机制是什么。为了解决这个问题，该项目结合了最近的几项技术进步，使其能够1)显著加速大脑海马区培养神经元的树突发育；2)通过高分辨率显微延时成像跟踪活神经元内蛋白质和细胞器的表达和运输；3)利用新颖的纳米制造技术，为细胞发育提供外部线索，创造出图案基底。这些实验将确定肌动蛋白和微管动力学的作用，以及外部线索（如细胞粘附分子和来自其他神经元的传入接触的位置）对树突分支的影响。结果将为神经发育的重要主题提供重大进展，其中基本信息仍然未知，跨学科的方法将加强生物学和工程学之间的相互作用。教育活动与研究的良好结合将对这所文理学院的研究经历产生重大影响，甚至对当地公立学校产生重大影响。

Nerve cells (neurons) in the mammalian brain often have elaborate treelike branching of fine cellular extensions called dendritic arbors, which receive the chemical signals of activity from other neurons. Like an antenna, the location and number of branches on a dendritic arbor organize the pattern of the afferent input, so the decision about where and when to form a branch is critical. The intracellular structures of these dendrites include cytoskeletal components called actin and microtubules, and these components are dynamic, changing the dendritic structure over time by elongation or retraction or stabilization of the branches at particular points. It remains unclear what the mechanisms are that determine the patterning of these often highly specific arbors during development and growth. To approach this question, this project combines several recent technical advances that give the ability to 1) accelerate dendritic development significantly in cultured neurons from the hippocampal region of the brain; 2) follow the expression and trafficking of proteins and organelles within the living neuron by high-resolution microscopic time-lapse imaging; and 3) to create patterned substrates, using novel creative nanofabrication techniques to provide external cues for cellular development. The experiments will determine the roles of actin and microtubule dynamics, and the influence of external cues such as cell adhesion molecules and location of afferent contacts from other neurons, on dendritic branching. Results will provide a major advance on an important topic of neural development where fundamental information is still unknown, and the interdisciplinary approach will enhance interactions between biology and engineering. The excellent integration of educational activities with the research will have a major impact on research experience in this liberal arts college, and even on the local public schools.