Huang Weifeng, Liu Yaoming, Li Jinmiao, Gao Yang, Tang Junjie, Yip Siuhang, Wang Xinyue, Zhang Hongwei, Ma Yujun, Su Shicai, Nie Jiahe, Lu Rong
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology Visual Science, Guangzhou, China.
Invest Ophthalmol Vis Sci. 2025 May 1;66(5):12. doi: 10.1167/iovs.66.5.12.
This study aims to explore how lipocalin 2 (LCN2) connects endoplasmic reticulum (ER) stress and inflammation in optic nerve injury (ONI) and identify potential therapeutic strategies.
An optic nerve crush (ONC) mouse model was used to investigate the role of ER stress and LCN2 in ONI. Immunofluorescence, quantitative PCR, and Western blot analyses were performed to assess ER stress markers, LCN2, inflammation-related genes, and retinal ganglion cell (RGC) survival, with or without treatment of 4PBA (an ER stress inhibitor) and TUN (an ER stress activator) in both the ONC model and BV2 cells. Lcn2 knockdown was achieved using small interfering RNA in BV2 cells and adeno-associated virus (AAV)-mediated gene silencing in vivo to explore underlying signaling pathways.
ER stress markers (GRP78, ATF4, CHOP) and LCN2 expression were increased in ONC retinas, accompanied by microglial activation and RGC loss. Inhibition of ER stress using 4PBA effectively decreased LCN2 expression, attenuated microglial activation, and increased RGC survival post-ONC. Intravitreal injection of recombinant LCN2 induced a proinflammatory phenotype in microglia and exacerbated neurotoxicity. AAV-mediated Lcn2 silencing mitigated microglial activation, reduced neuroinflammation, and provided RGC neuroprotection, surpassing 4PBA treatment. In vitro studies further confirmed that Lcn2 knockdown significantly reduced the inflammatory response in BV2 cells by inhibiting NLRP3 inflammasome activation via the TLR4/NF-κB pathway.
This study elucidates the critical role of LCN2 in linking ER stress and inflammation in ONI, offering a promising therapeutic target. AAV-mediated Lcn2 silencing outperforms broad ER stress inhibition, providing a novel strategy for treating optic nerve injuries.
本研究旨在探讨脂质运载蛋白2（LCN2）如何在视神经损伤（ONI）中连接内质网（ER）应激与炎症反应，并确定潜在的治疗策略。
采用视神经挤压（ONC）小鼠模型来研究ER应激和LCN2在ONI中的作用。通过免疫荧光、定量PCR和蛋白质印迹分析来评估ER应激标志物、LCN2、炎症相关基因以及视网膜神经节细胞（RGC）的存活情况，在ONC模型和BV2细胞中分别使用4PBA（一种ER应激抑制剂）和TUN（一种ER应激激活剂）进行处理。在BV2细胞中使用小干扰RNA实现Lcn2基因敲低，并在体内通过腺相关病毒（AAV）介导的基因沉默来探索潜在的信号通路。
ONC视网膜中ER应激标志物（GRP78、ATF4、CHOP）和LCN2表达增加，同时伴有小胶质细胞激活和RGC丢失。使用4PBA抑制ER应激可有效降低LCN2表达，减轻小胶质细胞激活，并增加ONC后RGC的存活。玻璃体内注射重组LCN2可诱导小胶质细胞产生促炎表型并加剧神经毒性。AAV介导的Lcn2基因沉默减轻了小胶质细胞激活，减少了神经炎症，并为RGC提供了神经保护，效果优于4PBA治疗。体外研究进一步证实，Lcn2基因敲低通过TLR4/NF-κB途径抑制NLRP3炎性小体激活，显著降低了BV2细胞中的炎症反应。
本研究阐明了LCN2在ONI中连接ER应激与炎症反应的关键作用，提供了一个有前景的治疗靶点。AAV介导的Lcn2基因沉默优于广泛的ER应激抑制，为治疗视神经损伤提供了一种新策略。
