In Vivo Reprogramming of Reactive Astrocyte and Chemogenetic Approach for SCI Repair

脊髓损伤(SCI)是一种毁灭性的事件，会导致巨大的身体和精神痛苦。 病人。脊髓损伤患者经常瘫痪，生活质量和生产力极低。 治疗干预(S)，即使是部分恢复功能也会显著提高患者的生活质量 那些病人。轴突变性是脊髓损伤后功能丧失的重要原因。不幸的是，轴突 在成年哺乳动物中，由于形成了不允许的环境，中枢神经系统在损伤后不能再生 主要是由星形胶质疤痕造成的。星形胶质细胞疤痕不仅形成物理屏障，而且还分泌抑制物， 如硫酸软骨素蛋白多糖(CSPGs)，以抑制受损轴突的再生长。以前的研究 表明CSPG的降解或其拮抗剂的应用可以促进脊髓损伤后轴突的再生。 然而，这些方法只能暂时去除抑制的CSPG，在促进轴突方面非常有限。 脊髓损伤后的再生和功能恢复。在这项研究中，我们将使用新的遗传方法永久地 改变星形胶质细胞瘢痕命运增强脊髓损伤后轴突的自我修复。我们假设在活体内 抑制反应性星形胶质细胞重新编程为神经元将促进脊髓损伤后的功能恢复 两种协同作用机制：1)减少星形胶质细胞增生及其抑制促进再生 下行运动束；2)形成神经元中继，重新连接受损的下行轴突和其 尾部靶神经元。我们将使用三个具体目标来检验这些假设。AIM 1将在体内进行检查 脊髓损伤后反应性星形胶质细胞的重编程。我们假设强迫表达的表型特异性 转录因子将抑制反应的星形胶质细胞转化为神经元，并整合到宿主中 电路。目标2将检查体内星形胶质细胞重新编程是否会促进轴突再生和 脊髓损伤后功能恢复情况。目标3将检查体内星形胶质细胞重新编程与 多神经营养因子D15A将进一步促进慢性脊髓损伤后轴突的再生和功能恢复。这个 拟议的研究将帮助我们评估脊髓损伤后体内星形胶质细胞重新编程的治疗潜力 并了解这种新的功能恢复方法的机制。这些研究可以帮助我们 开发急需的治疗脊髓损伤的新的有效疗法。

Spinal cord injury (SCI) is a devastating event resulting in enormous physical and emotional suffering in patients. SCI patients often live with paralysis and extremely reduced quality of life and productivity. Therapeutic intervention(s) to restore even partial function would significantly increase the quality of life for those patients. Axonal degeneration significantly contributes to functional loss after SCI. Unfortunately, axons in the adult mammalian CNS fail to regenerate after injury due to the non-permissive environment formed primarily by astroglial scars. Astroglial scars not only form a physical barrier, but they also secrete inhibitors, such as chondroitin sulfate proteoglycans (CSPGs), to inhibit the regrowth of injured axons. Previous studies show that degradation of CSPGs, or application of its antagonists, can promote axonal regeneration after SCI. However, these methods only temporarily remove the inhibitory CSPG and are very limited in promoting axonal regeneration and functional recovery after SCI. In this study, we will use novel genetic methods to permanently change the fate of astroglial scars to enhance self-repair of axons after SCI. We hypothesize that in vivo reprogramming of the inhibitory reactive astrocytes into neurons will promote functional recovery after SCI by two synergistic mechanisms: 1) decreasing the astrogliosis and its inhibition to promote regeneration of descending motor tracts; and 2) forming neuronal relay reconnecting the injured descending axons and its caudal target neurons. We will test these hypotheses using three specific aims. Aim 1 will examine in vivo reprogramming of reactive astrocytes after SCI. We hypothesize that forced expression of phenotype specific transcription factors will convert the inhibitory reactive astrocytes into neurons which could integrate into host circuits. Aim 2 will examine whether in vivo astrocyte reprogramming will promote axonal regeneration and functional recovery after SCI. Aim 3 will examine whether combination of in vivo astrocyte reprogramming with multineurotrophin D15A will further promote axonal regeneration and functional recovery after chronic SCI. The proposed studies will help us evaluate the therapeutic potential of in vivo astrocyte reprogramming after SCI and understand the mechanisms of this novel approach for functional recovery. These studies could help us develop the much-needed novel effective therapies for SCI.