Multipronged approach to promote functional axonal regeneration in the spinal cord after injury

项目摘要 在成熟的中枢神经系统中，损伤后缺乏成功的再生是由于内在的和 环境障碍。虽然在这一领域取得了进展，但克服这些障碍， 强健的功能性轴突再生和恢复仍然是一个重大的挑战。我们根据初步数据 并假设损伤后复发性DREADD介导的神经元激活是增强 功能性轴突再生此外，我们将测试神经元激活增加轴突的假设， 通过mTOR激活和增加动态微管的再生。我们将这两个假设 在体外使用成年背根神经节神经元培养物和在体内使用背根压碎、背柱 脊髓损伤（SCI）/周围神经移植物（PNG）和不完全颈部SCI/PNG模型。目标1： 将阐明如何重复，化学神经元激活增强轴突再生。在目标2中，我们 评估神经元激活-单独或与增加动态微管的操作组合 和mTOR激活-促进功能性轴突再生。总的来说，我们将：1）阐明机制 神经元激活如何促进生长的背后，潜在地确定新的治疗靶点; 2）确定 神经元激活在不同损伤模型（背根挤压，SCI）中增强再生的程度; 3)确定神经元激活是否在不同的神经元群体中具有不同或相似的效应（DRG与 CNS）; 4）测试是否使用独特的多方面方法促进有意义的轴突再生 a）使用化学发生神经元激活-可能沿着进一步增加动态微管 和/或mTOR激活-以增强轴突生长反应; B）提供更允许生长的 损伤后的环境（即用软骨素酶减轻神经胶质瘢痕的抑制性基质; PNG移植到SCI腔中;软骨素酶消化可塑性限制性神经束膜网）。 这些实验完成后，我们将确定新的治疗途径，以促进功能性 SCI后修复

PROJECT SUMMARY The lack of successful regeneration after injury in the mature central nervous system is due to intrinsic and environmental obstacles. Though progress in the field has been made, overcoming these barriers to result in robust functional axon regeneration and recovery is still a significant challenge. We build upon preliminary data and hypothesize that recurrent DREADD-mediated neuronal activation after injury is a means to enhance functional axon regeneration. Additionally, we will test the hypothesis that neuronal activation increases axon regeneration via both mTOR activation and increasing dynamic microtubules. We will these our hypotheses both in vitro using adult dorsal root ganglion neuron cultures and in vivo using dorsal root crush, dorsal columns spinal cord injury (SCI)/peripheral nerve graft (PNG), and incomplete cervical SCI/PNG models. In Aim 1, we will elucidate how repeated, chemogenetic neuronal activation enhances axon regeneration. In Aim 2, we will assess if neuronal activation – alone or in combination with manipulations that increase dynamic microtubules and mTOR activation – promotes functional axon regeneration. Collectively, we will: 1) elucidate mechanisms behind how neuronal activation enhances growth, potentially identifying new therapeutic targets; 2) determine the extent to which neuronal activation enhances regeneration in different injury models (dorsal root crush, SCI); 3) determine if neuronal activation has disparate or similar effects in different populations of neurons (DRG vs. CNS); 4) test whether meaningful axonal regeneration is facilitated using a unique, multi-faceted approach that: a) uses chemogenetic neuronal activation – possibly along with further increasing dynamic microtubules and/or mTOR activation – to enhance the axonal growth response; b) provides a more growth-permissive environment after an injury (i.e. mitigation of the inhibitory matrix of the glial scar with chondroitinase; transplantation of a PNG into an SCI cavity; chondroitinase digestion of plasticity-limiting perineuronal nets). After the completion of these experiments, we will have identified novel therapeutic avenues to foster functional repair after SCI.