中国神经再生研究(英文版) ›› 2021, Vol. 16 ›› Issue (10): 1996-1997.doi: 10.4103/1673-5374.308081

• 观点:视神经损伤修复保护与再生 • 上一篇    下一篇

基于MicroRNA治疗视神经病变–机遇与挑战

  

  • 出版日期:2021-10-15 发布日期:2021-03-19

MicroRNA-based therapeutics for optic neuropathy: opportunities and challenges

Heather K. Mak, Christopher K. S. Leung*   

  1. Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
  • Online:2021-10-15 Published:2021-03-19
  • Contact: Christopher K. S. Leung, MD, MBChB, cksleung@gmail.com.

摘要:

Neural Regen Res:为什么视网膜神经节细胞随年龄增长会失去轴突再生的能力?

     

随着microRNAmiRNA)基因表达技术的发展,越来越多证据表明了miRNA对哺乳动物视觉系统的发育、维持和修复的贡献。尽管对年轻和成熟视网膜神经节细胞(RGC)之间的轴突再生潜力的不同分子特征仍然知之甚少,但研究已经证明microRNA在协调中枢神经系统神经元轴突生长转录因子的表达中起着关键作用。视神经病变动物模型中miRNA介导的RGC凋亡减轻显示了miRNA的治疗潜力,但尚不清楚miRNA是否可以调控导致RGC轴突再生能力丧失的内在分子事件。由于RGC仅占视网膜细胞的5%,因此使用整个视网膜进行miRNA分析几乎无法明确RGCmiRNA的表达方式。

 

来自中国香港大学的Christopher K. S. Leung团队使用微阵列表征不同发育年龄(E21P6P30)纯化的啮齿动物RGCmiRNA谱的表达。他们发现从胚胎到成年年龄有76miRNA差异表达,其中包括六个成员中的五个miR-17 / 92簇的结构。在这个miRNA簇中,miR-19a在衰老的RGC中显着下调,有望靶向一种已知的视神经再生抑制剂—PTEN。随着时间的推移,轴突再生能力的发育障碍与miR-19a固有下降有关,减轻了PTEN抑制作用,从而抑制了轴突再生。细胞内miR-19a水平的增加显著增强了在微流室内培养的产后啮齿动物RGC的轴突生长。而降低miR-19a的内源性水平则表明轴突的生长明显减少。从6975岁的人类供体中补充了miR-19a纯化的RGC中,轴突生长得到了类似的增强。在视神经挤压的小鼠模型中,通过基于腺相关病毒的递送补充成年RGC中的miR-19a,可提高RGC存活率并促进轴突再生。但是,miRNA介导的PTEN抑制不能完全去除细胞内PTENmiRNA是基因表达的微调,而miR-19a上调的RGC的比例取决于AAV的转导效率。这一事实说明,与PTEN敲除视神经后转基因动物相比,miR-19a对轴突再生的影响更为微妙。虽然如此,Leung团队依然强调了基于microRNA的疗法可以使老化的RGC再生并促进视神经再生的潜力。

 

 

文章在《中国神经再生研究(英文版)》杂志20201010期发表。

https://orcid.org/0000-0003-4862-777X(Christopher K. S. Leung) 

Abstract: Optic nerve degeneration is a major cause of irreversible blindness worldwide with glaucoma being the most common optic neuropathy, affecting approximately 76 million people worldwide in 2020. The optic nerve comprises axons of retinal ganglion cells (RGCs), the output neurons of the inner retina. Protecting RGCs and axons from degeneration and regenerating RGC axons to preserve and recover vision in patients with progressive optic neuropathy is an unmet need. Unlike embryonic neurons, mature neurons of the mammalian central nervous system fail to regenerate their axons following injury. The age-related loss of axon regenerative capacity of RGCs over time renders vision loss from optic neuropathy irreversible. The failure of injured RGCs to regenerate axons is largely attributed to inhibitory molecules in the extrinsic environment and a change in the intrinsic molecular makeup of aging cells. Early studies have demonstrated that RGCs require specific molecular signals for the stimulation of axon growth even without inhibitory molecules in the extrinsic environment, leading successive efforts to focus on uncovering the intrinsic signaling pathways that control axon extension during RGC development. Phosphatase and tensin homolog (PTEN), suppressor of cytokine signaling 3 (SOCS3), dual leucine zipper kinase, and krüppel-like factor (KLF) family members are some of the transcription factors and proteins that have been demonstrated to govern the intrinsic signaling pathways of axon regeneration (He and Jin, 2016). Whereas the molecular signatures that contribute to the differential axon regenerative potential between young and mature RGCs remain poorly understood, increasing evidence has revealed that microRNAs play a critical role in orchestrating the expression of transcription factors for axon growth in neurons of the central nervous system. A recent study has unveiled a previously unrecognized involvement of the miR-19a/PTEN axis in regulating the developmental decline of axon regenerative capacity in RGCs, highlighting the potential of microRNA-based therapeutics to rejuvenate aged RGCs and promote optic nerve regeneration (Mak et al., 2019).