Quantifying Axon Growth in Complex Environments

描述（由申请人提供）：在复杂环境中量化轴突生长项目摘要：我们的长期目标是双重的：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，多种生长促进线索的组合将使轴突生长能够克服局部抑制环境（即，胶质疤痕），损伤后形成。 为了验证这一假设，需要制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生长促进线索的组合;以及（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，这些实验将首次测试指导线索的组合如何在抑制环境中促进轴突生长。 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线索的特定数量和比例相关联，从而为神经再生的新策略建立基础。 这项创新的多学科提案结合了主要研究者在神经元发育，再生和生物材料方面的互补专业知识以及电化学，微加工和表面表征方面的共同研究者，以制造能够提供精确数量的生物指导线索和电刺激的平台（目标1）。 目标2集中于确定特定刺激引导线索（即，电刺激、层粘连蛋白-1和神经生长因子）在增强神经突生长方面是协同的。 目的3集中于确定特定的刺激性引导线索是否可以促进神经突生长以克服抑制性环境（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受体以及聚集在微管细胞骨架功能上的下游激酶如何解释多种指导线索。 这些研究的结果将通过提供复杂环境中轴突生长要求的更全面知识来推进神经再生生物材料领域。 公共卫生相关性：神经损伤后不能再生，目前的医学实践无法有效地操纵神经再生的过程。 拟议的研究试图通过量化指导线索如何单独和组合促进轴突在抑制环境（如神经损伤部位）中的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.