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Invest Ophthalmol Vis Sci. 2020 Feb 7;61(2):31. doi: 10.1167/iovs.61.2.31.
To investigate the possible role of activating transcription factor 3 (ATF3) in retinal ganglion cell (RGC) neuroprotection and optic nerve regeneration after optic nerve crush (ONC).
Overexpression of proteins of interest (ATF3, phosphatase and tensin homolog [PTEN], placental alkaline phosphatase, green fluorescent protein) in the retina was achieved by intravitreal injections of recombinant adenovirus-associated viruses (rAAVs) expressing corresponding proteins. The number of RGCs and αRGCs was evaluated by immunostaining retinal sections and whole-mount retinas with antibodies against RNA binding protein with multiple splicing (RBPMS) and osteopontin, respectively. Axonal regeneration was assessed via fluorophore-coupled cholera toxin subunit B labeling. RGC function was evaluated by recording positive scotopic threshold response.
The level of ATF3 is preferentially elevated in osteopontin+/RBPMS+ αRGCs following ONC. Overexpression of ATF3 by intravitreal injection of rAAV 2 weeks before ONC promoted RBPMS+ RGC survival and preserved RGC function as assessed by positive scotopic threshold response recordings 2 weeks after ONC. However, overexpression of ATF3 and simultaneous downregulation of PTEN, a negative regulator of the mTOR pathway, combined with ONC, only moderately promoted short distance RGC axon regeneration (200 μm from the lesion site) but did not provide additional RGC neuroprotection compared with PTEN downregulation alone.
These results reveal a neuroprotective effect of ATF3 in the retina following injury and identify ATF3 as a promising agent for potential treatments of optic neuropathies.
研究激活转录因子 3（ATF3）在视神经挤压（ONC）后视网膜神经节细胞（RGC）神经保护和视神经再生中的可能作用。
通过注射重组腺相关病毒（rAAV）来实现感兴趣蛋白（ATF3、磷酸酶和张力蛋白同系物[PTEN]、胎盘碱性磷酸酶、绿色荧光蛋白）在视网膜中的过表达。用针对 RNA 结合蛋白多聚体（RBPMS）和骨桥蛋白的抗体对视网膜切片和全视网膜进行免疫染色，分别评估 RGC 和 αRGC 的数量。通过荧光素偶联霍乱毒素亚单位 B 标记评估轴突再生。通过记录负光阈值反应评估 RGC 功能。
在 ONC 后，ATF3 的水平优先在骨桥蛋白+/RBPMS+αRGC 中升高。在 ONC 前 2 周通过玻璃体内注射 rAAV 过表达 ATF3 可促进 RBPMS+RGC 存活，并通过记录 ONC 后 2 周的正光阈值反应来保留 RGC 功能。然而，ATF3 的过表达和 mTOR 通路的负调节剂 PTEN 的同时下调，结合 ONC，仅适度促进了短距离 RGC 轴突再生（距病变部位 200μm），但与单独下调 PTEN 相比，并没有提供额外的 RGC 神经保护作用。
这些结果揭示了损伤后 ATF3 在视网膜中的神经保护作用，并将 ATF3 确定为治疗视神经病变的有前途的药物。
