中国神经再生研究(英文版) ›› 2017, Vol. 12 ›› Issue (4): 525-528.doi: 10.4103/1673-5374.205080

• 综述:神经损伤修复保护与再生 • 上一篇    下一篇

RhoA可作为促进神经元存活和轴突再生的靶标

  

  • 收稿日期:2017-03-31 出版日期:2017-04-15 发布日期:2017-04-15
  • 基金资助:

    本研究由(NIH)R01-NS092876、SHC-85400(Shriners研究基金会)、SHC-85220(Shriners研究基金会)和SHC-84293(Shriners研究基金会)共同赞助

RhoA as a target to promote neuronal survival and axon regeneration

Jianli Hu1, Michael E. Selzer1, 2   

  1. 1 Shriners Hospitals for Children, Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA; 2 Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
  • Received:2017-03-31 Online:2017-04-15 Published:2017-04-15
  • Contact: Michael E. Selzer, Ph.D., mselzer@temple.edu.
  • Supported by:

    This study was supported by R01-NS092876 (NIH, MES, PI); SHC-85400 (Shriners Research Foundation, MES, PI); SHC-85220 (Shriners Research Foundation, MES, PI) and SHC-84293 (Shriners Research Foundation, JH, PI).

摘要:

 

RhoA是在脊髓损伤位点局部被激活和/或上调的小GTP酶,并且被认为是限制损伤恢复的重要参与者。RhoA表达的增加过程可持续4周,证据表明RhoA是涉及限制脊髓损伤后恢复的几种细胞外分子的神经元内信号汇合点,例如,硫酸软骨素蛋白聚糖和髓鞘相关糖蛋白,少突胶质细胞髓鞘糖蛋白,Nogo和其相应受体。这使RhoA成为一种有前景的研究靶标,即促进轴突生长和提高脊髓损伤后的功能恢复。RhoA限制恢复的手段是复杂的,并且可能涉及对至少两种脊髓损伤类型的神经反应:1)神经元凋亡;和2)再生失效。这两种现象如何相互关联并不清楚,但并不是简单的死亡神经元无法再生。体内哺乳动物脊髓损伤的实验结果很难解释这一现象原因有三:1)难以区分受损轴突是能够真正再生的旁路发芽轴突。2)损伤部位附近的神经元死亡原因不明确。3)两种效应的时间过程重叠。

文中研究使用海七鳃鳗作为模型来解决这些模糊问题,因为其体型大,并且具有单独确定的网状脊髓神经元,这些可以显示它们的轴突通过相同脊髓环境再生的能力和在轴突切除后长期生存的能力之间的巨大异质性。文章使用七鳃鳗的这些功能来分析轴突切断诱发的逆行神经元死亡因素,以及轴突再生失败的原因。此外,在脊髓损伤后的早期时间点轴突再生不良的神经元,最终会在后期死亡。这表明抑制轴突再生和母体神经元存活的途径可能会通过RhoA汇集。

ORCID:0000-0002-1141-217X(Michael E. Selzer);0000-0002-3022-1950(Jianli Hu)

Abstract:

Paralysis following spinal cord injury (SCI) is due to failure of axonal regeneration. It is believed that the capacities of neurons to regrow their axons are due partly to their intrinsic characteristics, which in turn are greatly influenced by several types of inhibitory molecules that are present, or even increased in the extracellular environment of the injured spinal cord. Many of these inhibitory molecules have been studied extensively in recent years. It has been suggested that the small GTPase RhoA is an intracellular convergence point for signaling by these extracellular inhibitory molecules, but due to the complexity of the central nervous system (CNS) in mammals, and the limitation of pharmacological tools, the specific roles of RhoA are unclear. By exploiting the anatomical and technical advantages of the lamprey CNS, we recently demonstrated that RhoA knockdown promotes true axon regeneration through the lesion site after SCI. In addition, we found that RhoA knockdown protects the large, identified reticulospinal neurons from apoptosis after their axons were axotomized in spinal cord. Therefore, manipulation of the RhoA signaling pathway may be an important approach in the development of treatments that are both neuroprotective and axon regeneration-promoting, to enhance functional recovery after SCI.

Key words: RhoA, spinal cord injury, neuronal survival, apoptosis, axon regeneration, morpholino, C3 transferase