Tang Wenyi, Zhai Ruyi, Ma Jun, Xu Gezhi
Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, 200031, China.
Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031, China.
Mol Med. 2025 May 15;31(1):190. doi: 10.1186/s10020-025-01250-1.
Retinal degeneration is a leading cause of blindness worldwide. The induction of ferroptosis has been identified as an important mechanism contributing to the loss of photoreceptors in retinal degeneration. Lipocalin-2 (LCN2) exhibits iron-regulatory properties and may modulate cell viability in various diseases. However, the effects of LCN2 on ferroptosis in retinal degeneration remain unclear.
A light-induced injury model using 661W photoreceptor cells and a light-induced retinal degeneration male rat model were established. LCN2 protein expression was assessed by western blotting. The effects of LCN2 on ferroptosis in vitro were investigated by using recombinant LCN2 protein (rLCN2) and small-interfering RNA (siRNA) targeting LCN2 (siLCN2). Fe, malondialdehyde (MDA), tripeptide glutathione (GSH) levels, and the expression of ferroptosis-associated proteins (solute carrier family 7 member 11 [SLC7A11] and glutathione peroxidase-4 [GPX4]) were measured. A phosphokinase array and western blotting were performed to elucidate the mechanisms underlying LCN2-modulated photoreceptor ferroptosis. Additionally, the protective effects of LCN2 knockdown using adeno-associated virus (AAV)-expressing short hairpin RNA (shRNA) targeting LCN2 (AAV-shRNA-LCN2) on retinal structure and function in vivo were evaluated by hematoxylin and eosin staining and electroretinography.
LCN2 expression was significantly upregulated following light exposure. Treatment with rLCN2 significantly induced ferroptosis in photoreceptor cells, as shown by decreased cell viability, increased Fe levels, inhibition of SLC7A11 and GPX4 expression, depletion of GSH, and enhanced MDA levels, whereas siLCN2 protected against these effects. Exposure of photoreceptor cells to rLCN2 activated c-Jun N-terminal kinase (JNK), and administration of the JNK inhibitor SP600125 protected photoreceptor cells from ferroptosis. Lastly, AAV-shRNA-LCN2 administration inhibited light-induced ferroptosis in the retina, and protected the retinal structure and function in vivo.
LCN2 is a key regulator of light-induced ferroptosis in photoreceptors by modulating the JNK pathway. Therefore, LCN2 presents a new target for the treatment of retinal degeneration.
视网膜变性是全球失明的主要原因。铁死亡的诱导已被确定为导致视网膜变性中光感受器丧失的重要机制。脂质运载蛋白2（LCN2）具有铁调节特性，可能在各种疾病中调节细胞活力。然而，LCN2对视网膜变性中铁死亡的影响仍不清楚。
建立了使用661W光感受器细胞的光诱导损伤模型和光诱导视网膜变性雄性大鼠模型。通过蛋白质免疫印迹法评估LCN2蛋白表达。使用重组LCN2蛋白（rLCN2）和靶向LCN2的小干扰RNA（siRNA）（siLCN2）研究LCN2在体外对铁死亡的影响。测量铁、丙二醛（MDA）、三肽谷胱甘肽（GSH）水平以及铁死亡相关蛋白（溶质载体家族7成员11 [SLC7A11]和谷胱甘肽过氧化物酶4 [GPX4]）的表达。进行磷酸激酶阵列分析和蛋白质免疫印迹法以阐明LCN2调节光感受器铁死亡的潜在机制。此外，通过苏木精和伊红染色及视网膜电图评估使用表达靶向LCN2的短发夹RNA（shRNA）的腺相关病毒（AAV）（AAV-shRNA-LCN2）敲低LCN2对体内视网膜结构和功能的保护作用。
光照后LCN2表达显著上调。rLCN2处理显著诱导光感受器细胞发生铁死亡，表现为细胞活力降低、铁水平升高、SLC7A11和GPX4表达受抑制、GSH耗竭以及MDA水平升高，而siLCN2可防止这些效应。光感受器细胞暴露于rLCN2会激活c-Jun氨基末端激酶（JNK），给予JNK抑制剂SP600125可保护光感受器细胞免于铁死亡。最后，给予AAV-shRNA-LCN2可抑制视网膜中光诱导的铁死亡，并在体内保护视网膜结构和功能。
LCN2通过调节JNK途径是光诱导的光感受器铁死亡的关键调节因子。因此，LCN2为视网膜变性的治疗提供了一个新靶点。
