Axon motility and guidance in three dimensional matrices

对控制轴突生长和指导的过程的详细了解对于 了解神经系统的发展和工程成功再生， 脊髓损伤后切断的神经元的重新连接。许多信号通路负责 增强或抑制生长以及用于吸引和排斥引导。但 我们对轴突运动机制的绝大多数认识来自于对生长锥的研究 在平坦、坚硬的基底上导航。有相当多的证据表明，细胞运动在复杂的，柔韧的，三 三维（3D）细胞外环境可能与涂覆的玻璃盖玻片上的非常不同。目标 这一探索性研究的建议是开发必要的工具，以探测细胞骨架动力学， 3D胶原基质中的生长锥，并开始研究细胞骨架对细胞外 3D的导航提示。我们的具体目标是：（1）三维测量生长锥细胞骨架动力学 胶原蛋白凝胶。(2)量化导向因子梯度对生长锥细胞骨架动力学的影响 在3D中。- - 这些技术的发展，以调查细胞骨架动力学的指导，在3D凝胶将 为解决有关生物物理和生物化学的基本问题奠定基础 轴突运动的基础机制，并将奠定基础的发展控制 以可预测的方式影响轴突运动的环境操纵。我们将能够 生成抑制模型、发育过程中或胶质疤痕中遇到的线索，分析 这些线索影响轴突运动的机制，然后系统地操纵环境 和信号转导通路，以验证有关轴突导向机制的假设， 测试干预以控制轴突生长。

A detailed understanding of the processes that control axon growth and guidance is essential for understanding the development of the nervous system and for engineering successful regrowth and reconnection of severed neurons following spinal cord injury. Many of the signaling pathways responsible for enhancing or inhibiting growth and for attractive and repulsive guidance have been identified. However, the vast majority of our knowledge of the mechanisms of axon motility come from studies of growth cones navigating on flat, stiff substrates. There is considerable evidence that cell motility in complex, pliable, three dimensional (3D) extracellular environments can be very different than on a coated glass coverslip. The goal of this exploratory research proposal is to develop the tools necessary to probe the cytoskeletal dynamics of growth cones in 3D collagen matrices and to initiate studies of the cytoskeletal response to extracellular guidance cues in 3D. Our specific aims are to: (1) Measure growth cone cytoskeletal dynamics in 3D collagen gels. (2) Quantify the effect of gradients of guidance factors on growth cone cytoskeletal dynamics in 3D. ¿ ' - The development of these techniques to investigate the cytoskeletal dynamics of guidance in 3D gels will lay the groundwork for addressing fundamental questions about the biophysical and biochemical mechanisms that underlie axon motility, and will lay the groundwork for the development of controlled manipulations of the environment that impact axon motility in predictable ways. We will be in a position to generate models of inhibitory,cues encountered during development or in the glial scar, analyze the mechanisms by which those cues affect axon motility, and then systematically manipulate the environment and the signal transduction pathways to validate hypothesis about the mechanisms of axon guidance or to test interventions to control axon growth.