Quantifying Axon Growth in Complex Environments

描述(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：阐明损伤后轴突指导的细胞和分子机制，以及开发支持和促进轴突生长的生物材料平台。我们的工作假设是，多种促生长信号的组合将使轴突生长能够克服损伤后形成的局部抑制环境(即胶质瘢痕)。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促进生长的线索的组合；以及(2)提供一种手段，用于测试刺激性环境与抑制性环境。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组合如何在抑制环境中促进轴突生长。与NIBIB通过促进生物工程的基本发现、设计和开发来改善健康的使命相关，我们的目标是将轴突生长和方向与特定数量和比例的刺激和抑制线索联系起来，从而为神经再生的新策略奠定基础。这一创新的多学科方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免费专业知识，以及联合研究员在电化学、微制造和表面表征方面的专业知识，构建了一个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)。目的2着重于确定特定的刺激性引导信号(即电刺激、层粘连蛋白-1和神经生长因子)在促进神经突起生长方面是否具有协同作用。目的3着重于确定特定的刺激性引导信号是否能促进轴突生长以克服抑制环境(即硫酸软骨素蛋白多糖)。通过药物抑制剂和激光灭活方法，我们将确定整合素受体和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，以解释多种指导信号。这些研究的结果将提供更全面的关于复杂环境中轴突生长要求的知识，从而推动神经再生生物材料领域的发展。公共卫生相关性：神经在受伤后不能再生，目前的医学实践无法有效地操纵神经再生的过程。这项拟议的研究试图通过量化指导线索如何在抑制环境中(如神经损伤部位)促进轴突生长来解决这一问题。

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.