Oxidative damage in retinal pigment epithelial cells (RPE) is considered to be a crucial pathogenesis of age-related macular degeneration (AMD). Although dysregulation of the DNA repair system has been found in RPE cells of AMD patients, the detailed molecular mechanisms of this dysregulation and their relationship with the intraocular microenvironment of AMD patients remain unclear. Here, we established an RPE model of H₂O₂-induced oxidative stress and found that Sirtuin 1 (Sirt1)-mediated deacetylation of E2F transcription factor 1 (E2F1) was required for oxidation resistance in RPE cells. Moreover, E2F1 induced the expression of the chromatin-binding protein, high mobility group AT-Hook 1 (HMGA1), which promoted the transcription of glucose 6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, to increase NADPH level for antioxidant defense. Interrupting the E2F1/HMGA1/G6PD regulatory axis increased reactive oxygen species (ROS) levels, DNA damage, and apoptosis in RPE cells under oxidative stress. Notably, interleukin 6 (IL-6), an inflammatory cytokine that is known to be upregulated in the intraocular fluid of AMD patients, induced phosphorylation (S47) of Sirt1 by activating PI3K/AKT/mTOR signaling, thereby inhibiting Sirt1 activity and increasing the acetylation of E2F1. Specific inhibitors of PI3K/AKT/mTOR signaling decreased DNA damage and ROS while increasing NADPH in RPE cells. Collectively, our findings demonstrate that IL-6-induced acetylation of E2F1 impairs the antioxidant capacity of RPE cells by disturbing the pentose phosphate pathway, which elucidates a relationship between the intraocular microenvironment and RPE oxidative damage in AMD and provides a possible therapeutic target for AMD.

视网膜色素上皮细胞（RPE）的氧化损伤被认为是年龄相关性黄斑变性（AMD）的关键发病机理。尽管在AMD患者的RPE细胞中发现了DNA修复系统的失调，但这种失调的详细分子机制及其与AMD患者眼内微环境的关系仍不清楚。在这里，我们建立了H ₂ O ₂的RPE模型诱导氧化应激，并发现Sirtuin 1（Sirt1）介导的E2F转录因子1（E2F1）脱乙酰化是RPE细胞抗氧化所必需的。此外，E2F1诱导了染色质结合蛋白高迁移率族AT-Hook 1（HMGA1）的表达，从而促进了戊糖磷酸途径的限速酶葡萄糖6磷酸脱氢酶（G6PD）的转录。增加NADPH含量以抗氧化。中断E2F1 / HMGA1 / G6PD调节轴会增加RPE细胞在氧化应激下的活性氧（ROS）水平，DNA损伤和细胞凋亡。值得注意的是，白细胞介素6（IL-6）是一种已知在AMD患者眼内液中被上调的炎症细胞因子，它通过激活PI3K / AKT / mTOR信号传导诱导Sirt1的磷酸化（S47），从而抑制Sirt1活性并增加E2F1的乙酰化。PI3K / AKT / mTOR信号传导的特异性抑制剂可降低RPE细胞中的DNA损伤和ROS，同时增加NADPH。总的来说，我们的研究结果表明，IL-6诱导的E2F1乙酰化通过干扰戊糖磷酸途径而损害RPE细胞的抗氧化能力，这阐明了眼内微环境与RPE氧化损伤之间的关系，并为AMD提供了可能的治疗靶点。