Quantifying Axon Growth in Complex Environments

描述（由申请人提供）：量化复杂环境中的轴突生长项目摘要：我们的长期目标有两个：阐明损伤后轴突引导的细胞和分子机制，并开发生物材料平台以支持和增强轴突生长。 我们的工作假设是，多种生长促进信号的结合将使轴突生长能够克服损伤后形成的局部抑制环境（即神经胶质疤痕）。 为了检验这一假设，需要建造一个新的物理平台来研究神经元的生长。 该平台将（1）以可控和可量化的方式提供促进生长的线索组合； (2) 提供一种测试刺激环境与抑制环境的方法。 这些平台将使创新实验成为可能，首次测试引导线索的组合如何促进抑制环境中的轴突生长。 NIBIB 的使命是通过促进生物工程的基础发现、设计和开发来改善健康，我们的目标是将轴突生长和方向与刺激和抑制信号的特定数量和比例相关联，从而为神经再生的新策略奠定基础。 这项创新的多学科提案结合了首席研究员在神经元发育、再生和生物材料方面的专业知识以及联合研究员在电化学、微加工和表面表征方面的互补专业知识，以制造一个能够提供精确数量的生物引导线索和电刺激的平台（目标 1）。 目标 2 侧重于确定特定的刺激引导线索（即电刺激、层粘连蛋白-1 和神经生长因子）是否在促进神经突生长方面具有协同作用。 目标 3 侧重于确定特定的刺激引导信号是否可以促进神经突生长以克服抑制环境（即硫酸软骨素蛋白聚糖）。 通过药理学抑制剂和激光灭活方法，我们将确定整合素和 trk 受体以及汇聚在微管细胞骨架上的下游激酶如何发挥作用来解释多个引导线索。 这些研究的结果将提供有关复杂环境中轴突生长要求的更全面的知识，从而推动神经再生生物材料领域的发展。 公共健康相关性：神经受伤后无法再生，目前的医疗实践无法有效地操纵神经再生过程。 拟议的研究旨在通过量化单独和组合的引导线索如何促进神经损伤部位等抑制环境中的轴突生长来解决这个问题。

DESCRIPTION (provided by applicant): Quantifying Axon Growth in Complex Environments Project Summary: Our long-term objective is twofold: to elucidate the cellular and molecular mechanisms that underlie axon guidance after injury, and to develop biomaterial platforms to support and enhance axon growth. Our working hypothesis is that the combination of multiple growth-promoting cues will enable axon growth to overcome the local inhibitory environment (i.e., glial scar) that develops post-injury. To test this hypothesis will require the fabrication of a new physical platform upon which to study neuronal growth. The platform will (1) deliver a combination of growth-promoting cues in a controllable and quantifiable manner; and (2) provide a means by which to test a stimulatory environment against an inhibitory environment. These platforms will make possible innovative experiments that will test for the first time how combinations of guidance cues promote axon growth in an inhibitory environment. Relevant to NIBIB's mission to improve health by promoting fundamental discoveries, design, and development in bioengineering, our objective is to correlate axon growth and direction to specific quantities and ratios of stimulatory and inhibitory cues, thus establishing the basis for new strategies for nerve regeneration. This innovative multidisciplinary proposal combines the complimentary expertise of the Principal Investigator in neuronal development, regeneration, and biomaterials and the Co-Investigator in electrochemistry, microfabrication, and surface characterization, to fabricate a platform capable of delivering precise quantities of both biological guidance cues and electrical stimulation (Aim 1). Aim 2 focuses on determining if specific stimulatory guidance cues (i.e., electrical stimulation, laminin-1, and nerve growth factor) are synergistic at enhancing neurite growth. Aim 3 focuses on determining if specific stimulatory guidance cues can promote neurite growth to overcome an inhibitory environment (i.e., chondroitin sulfate proteoglycans). With pharmacological inhibitors and laser inactivation approaches, we will determine how integrin and trk receptors and downstream kinases that converge on the microtubule cytoskeleton function to interpret multiple guidance cues. Results from these studies will advance the field of biomaterials for nerve regeneration by providing more comprehensive knowledge of the requirements for axon growth in complex environments. PUBLIC HEALTH RELEVANCE: Nerves fail to regenerate after injury and current medical practice is unable to manipulate effectively the process of nerve regeneration. The proposed research seeks to solve this problem by quantifying how guidance cues, both individually and in combination, promote axon growth in an inhibitory environment such as a nerve injury site.