Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Henan Provincial Ophthalmic Hospital, Zhengzhou, Henan 450000, China.
The Key Laboratory for Human Disease Gene Study of Sichuan Province, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China.
Curr Med Chem. 2024;31(25):4022-4033. doi: 10.2174/0109298673240896231027053716.
Retinal pigment epithelium (RPE) 65 is a key enzyme in the visual cycle involved in the regeneration of 11-cis-retinal. Mutations in the human RPE65 gene cause Leber's congenital amaurosis (LCA), a severe form of an inherited retinal disorder. Animal models carrying Rpe65 mutations develop early-onset retinal degeneration. In particular, the cones degenerate faster than the rods. To date, gene therapy has been used successfully to treat RPE65-associated retinal disorders. However, gene therapy does not completely prevent progressive retinal degeneration in patients, possibly due to the vulnerability of cones in these patients. In the present study, we tested whether leukemia inhibitory factor (LIF), a trophic factor, protects cones in rd12 mice harboring a nonsense mutation in Rpe65.
LIF was administered to rd12 mice by intravitreal microinjection. Apoptosis of retinal cells was analyzed by TUNEL assay. The degeneration of cone cells was evaluated by immunostaining of retinal sections and retinal flat-mounts. Signaling proteins regulated by LIF in the retinal and cultured cells were determined by immunoblotting.
Intravitreal administration of LIF activated the STAT3 signaling pathway, thereby inhibiting photoreceptor apoptosis and preserving cones in rd12 mice. Niclosamide (NCL), an inhibitor of STAT3 signaling, effectively blocked STAT3 signaling and autophagy in cultured 661W cells treated with LIF. Co-administration of LIF with NCL to rd12 mice abolished the protective effect of LIF, suggesting that STAT3 signaling and autophagy mediate the protection.
LIF is a potent factor that protects cones in rd12 mice. This finding implies that LIF can be used in combination with gene therapy to achieve better therapeutic outcomes for patients with RPE65-associated LCA.
视网膜色素上皮（RPE）65 是视觉循环中涉及 11-顺式视黄醛再生的关键酶。人类 RPE65 基因突变导致莱伯先天性黑蒙（LCA），这是一种遗传性视网膜疾病的严重形式。携带 Rpe65 突变的动物模型会发生早期视网膜变性。特别是，锥体比杆体更快地退化。迄今为止，基因疗法已成功用于治疗与 RPE65 相关的视网膜疾病。然而，基因疗法并不能完全阻止这些患者的进行性视网膜变性，这可能是由于这些患者的锥体易感性。在本研究中，我们测试了白血病抑制因子（LIF）是否作为一种营养因子保护携带 Rpe65 无义突变的 rd12 小鼠中的锥体。
通过玻璃体内微注射将 LIF 施用于 rd12 小鼠。通过 TUNEL 测定分析视网膜细胞的凋亡。通过对视网膜切片和视网膜平面标本进行免疫染色评估锥体细胞的变性。通过免疫印迹测定确定 LIF 在视网膜和培养细胞中调节的信号蛋白。
玻璃体内给予 LIF 激活了 STAT3 信号通路，从而抑制了 rd12 小鼠中的光感受器细胞凋亡并保留了锥体。STAT3 信号抑制剂尼克罗米酚（NCL）有效阻断了 LIF 处理的培养的 661W 细胞中的 STAT3 信号和自噬。将 LIF 与 NCL 共同给予 rd12 小鼠可消除 LIF 的保护作用，表明 STAT3 信号和自噬介导了保护作用。
LIF 是保护 rd12 小鼠中锥体的有效因子。这一发现表明，LIF 可与基因疗法联合使用，为 RPE65 相关 LCA 患者带来更好的治疗效果。
