Chronic low-grade retinal inflammation is an essential contributor to the pathogenesis of diabetic retinopathy (DR). It is characterized by increased retinal cell expression and secretion of a variety of inflammatory cytokines; among these, IL-1β has the reputation of being a major driver of cytokine-induced inflammation. IL-1β and other cytokines drive inflammatory changes that cause damage to retinal cells, leading to the hallmark vascular lesions of DR; these include increased leukocyte adherence, vascular permeability, and capillary cell death. Nuclear factor of activated T-cells (NFAT) is a transcriptional regulator of inflammatory cytokines and adhesion molecules and is expressed in retinal cells. Consequently, it may influence multiple pathogenic steps early in DR. We investigated the NFAT-dependency of IL-1β-induced inflammation in human Müller cells (hMC) and human retinal microvascular endothelial cells (hRMEC). Our results show that an NFAT inhibitor, Inhibitor of NFAT-Calcineurin Association-6 (INCA-6), decreased IL-1β-induced expression of IL-1β and TNFα in hMC, while having no effect on VEGF, CCL2, or CCL5 expression. We also demonstrate that INCA-6 attenuated IL-1β-induced increases of IL-1β, TNFα, IL-6, CCL2, and CCL5 (inflammatory cytokines and chemokines), and ICAM-1 and E-selectin (leukocyte adhesion molecules) expression in hRMEC. INCA-6 similarly inhibited IL-1β-induced increases in leukocyte adhesion in both hRMEC monolayers in vitro and an acute model of retinal inflammation in vivo. Finally, INCA-6 rescued IL-1β-induced permeability in both hRMEC monolayers in vitro and an acute model of retinal inflammation in vivo. Taken together, these data demonstrate the potential of NFAT inhibition to mitigate retinal inflammation secondary to diabetes.

慢性低度视网膜炎症是糖尿病视网膜病变（DR）发病机制的重要因素。其特点是视网膜细胞表达和分泌多种炎症细胞因子增加；其中，IL-1β 被誉为细胞因子诱导炎症的主要驱动因素。 IL-1β 和其他细胞因子驱动炎症变化，对视网膜细胞造成损害，导致 DR 的标志性血管病变；这些包括增加白细胞粘附、血管通透性和毛细血管细胞死亡。活化 T 细胞核因子 (NFAT) 是炎症细胞因子和粘附分子的转录调节因子，在视网膜细胞中表达。因此，它可能影响 DR 早期的多个致病步骤。我们研究了人 Müller 细胞 (hMC) 和人视网膜微血管内皮细胞 (hRMEC) 中 IL-1β 诱导炎症的 NFAT 依赖性。我们的结果表明，NFAT 抑制剂，即N FAT- C alcineurin A sociation-6 (INCA-6)抑制剂，可降低 hMC 中 IL-1β 诱导的 IL-1β 和 TNFα 表达，同时对 VEGF、CCL2 没有影响，或CCL5表达。我们还证明，INCA-6 减弱了 IL-1β 诱导的 IL-1β、TNFα、IL-6、CCL2 和 CCL5（炎性细胞因子和趋化因子）以及 ICAM-1 和 E-选择素（白细胞粘附分子）表达的增加在 hRMEC 中。 INCA-6 同样抑制 IL-1β 诱导的体外hRMEC 单层和体内急性视网膜炎症模型中白细胞粘附的增加。最后，INCA-6 挽救了体外hRMEC 单层和体内急性视网膜炎症模型中 IL-1β 诱导的通透性。 总而言之，这些数据证明了 NFAT 抑制在减轻糖尿病继发的视网膜炎症方面的潜力。