中国神经再生研究(英文版) ›› 2023, Vol. 18 ›› Issue (4): 840-848.doi: 10.4103/1673-5374.344952

• 原著:视神经损伤修复保护与再生 • 上一篇    下一篇

西尼莫德对实验性青光眼视网膜和高级视觉通路神经保护的作用

  

  • 出版日期:2023-04-15 发布日期:2022-10-29
  • 基金资助:
    澳大利亚国家健康与医学研究委员会(NHMRC)、Perpetual Hilcrest、澳大利亚眼科研究所(ORIA)和澳大利亚新南威尔士州麦考瑞大学资助;澳大利亚诺华公司资助

Siponimod exerts neuroprotective effects on the retina and higher visual pathway through neuronal S1PR1 in experimental glaucoma

Devaraj Basavarajappa*, Vivek Gupta*, Nitin Chitranshi, Roshana Vander Wall, Rashi Rajput, Kanishka Pushpitha, #br# Samridhi Sharma, Mehdi Mirzaei, Alexander Klistorner, Stuart L. Graham#br#   

  1. Department of Clinical Medicine, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, Australia
  • Online:2023-04-15 Published:2022-10-29
  • Contact: Devaraj Basavarajappa, PhD, devaraj.basavarajappa@mq.edu.au; Vivek Gupta, PhD, vivek.gupta@mq.edu.au.
  • Supported by:
    This investigator-initiated study grant (to SLG) was funded by Novartis, Australia. The investigators also like to acknowledge the funding support from the National Health and Medical Research Council (NHMRC) of Australia, Perpetual Hilcrest, Ophthalmic Research Institute of Australia (ORIA) and Macquarie University, NSW, Australia. 

摘要:

鞘氨醇-1-磷酸受体(S1PR)信号调节着中枢神经系统(CNS)的各种病理生理过程,但其在神经退行性疾病中的作用在很大程度上仍未得到确认。西尼莫德是S1P1和S1P5受体的特异性调节剂,是治疗继发进展型多发性硬化的免疫抑制药物。为研究西尼莫德在体内对视网膜和大脑的神经保护特性,实验建立了由慢性眼压升高(IOP)或急性N-甲基-D-天门冬氨酸(NMDA)兴奋性毒性诱发的视神经损伤模型。通过在Syn1启动子下表达AAV-PHP.eB-Cre重组酶使S1PR1flox/flox小鼠产生神经元特异性缺失,以确定S1PR1在神经元中的作用。视网膜电生理反应、视网膜和视神经的组织学和免疫荧光分析显示,在慢性和急性视神经损伤模型中,西尼莫德显示出明显的神经保护作用;同时,西尼莫德对视神经损伤引起的大脑高级视觉中心的跨神经元退行性变化也显示出明显的保护作用。西尼莫德干预还减少了小胶质细胞的激活和沿视觉通路的反应性胶质增生,明显地提高了视网膜和大脑中的神经保护性Akt和Erk1/2的激活。在慢性视神经损伤条件下, S1PR1在神经元中的特异性缺失会增强视网膜和背外侧膝状核(dLGN)的退行性变化,并削弱西尼莫德的保护作用。以上实验数据表明,西尼莫德通过S1PR1在中枢神经系统的神经元中发挥直接的神经保护作用,而不依赖于其外周的免疫调节作用。从而提示,神经元S1PR1是一个神经保护的干预标靶,西尼莫德对它的调节对于减轻青光眼病情有积极意义。

https://orcid.org/0000-0003-0997-0196 (Devaraj Basavarajappa); https://orcid.org/0000-0002-0202-7843 (Vivek Gupta)

Abstract: Sphingosine-1-phosphate receptor (S1PR) signaling regulates diverse pathophysiological processes in the central nervous system. The role of S1PR signaling in neurodegenerative conditions is still largely unidentified. Siponimod is a specific modulator of S1P1 and S1P5 receptors, an immunosuppressant drug for managing secondary progressive multiple sclerosis. We investigated its neuroprotective properties in vivo on the retina and the brain in an optic nerve injury model induced by a chronic increase in intraocular pressure or acute N-methyl-D-aspartate excitotoxicity. Neuronal-specific deletion of sphingosine-1-phosphate receptor (S1PR1) was carried out by expressing AAV-PHP.eB-Cre recombinase under Syn1 promoter in S1PR1flox/flox mice to define the role of S1PR1 in neurons. Inner retinal electrophysiological responses, along with histological and immunofluorescence analysis of the retina and optic nerve tissues, indicated significant neuroprotective effects of siponimod when administered orally via diet in chronic and acute optic nerve injury models. Further, siponimod treatment showed significant protection against trans-neuronal degenerative changes in the higher visual center of the brain induced by optic nerve injury. Siponimod treatment also reduced microglial activation and reactive gliosis along the visual pathway. Our results showed that siponimod markedly upregulated neuroprotective Akt and Erk1/2 activation in the retina and the brain. Neuronal-specific deletion of S1PR1 enhanced retinal and dorsolateral geniculate nucleus degenerative changes in a chronic optic nerve injury condition and attenuated protective effects of siponimod. In summary, our data demonstrated that S1PR1 signaling plays a vital role in the retinal ganglion cell and dorsolateral geniculate nucleus  neuronal survival in experimental glaucoma, and siponimod exerts direct neuroprotective effects through S1PR1 in neurons in the central nervous system independent of its peripheral immuno-modulatory effects. Our findings suggest that neuronal S1PR1 is a neuroprotective therapeutic target and its modulation by siponimod has positive implications in glaucoma conditions. 

Key words: glaucoma, intraocular pressure, neurodegeneration, neuroprotection, optic nerve injury, retinal ganglion cells, siponimod, sphingosine-1-phosphate