Shandong University of Traditional Chinese Medicine, Jinan 250002, China.
School of Ophthalmology & Optometry, Shandong University of Traditional Chinese Medicine, Jinan 250002, China.
Int Immunopharmacol. 2020 Feb;79:106107. doi: 10.1016/j.intimp.2019.106107. Epub 2019 Dec 18.
Uveitis is the most common cause in inflammatory eye diseases that can lead to visual impairment even blindness worldwide. T helper (Th) 17 and regulatory T (Treg) cells are critical mediators for immune response. Notch signaling can regulate the cell differentiation, playing a role in the pathogenesis of the diseases. In this study, we measured the expression levels of Notch1, DLL4, IL-10, IL-17, RORγt and Foxp3 in T cells from lymph node, spleen and eye tissues in experimental autoimmune uveitis (EAU) rats in vitro, determined the ratios of CD4/CD8 and Th17/Treg. Moreover, we also investigated the effect of Notch signaling inhibitor N-(N-(3,5-Difluorophenacetyl-L-alanyl))-S-phenylglycine t-Butyl Ester (DAPT) on Notch1, DLL4 expression and on Th17, Treg cell differentiation. The results indicated that the pathogenesis of uveitis accompanied by the elevated expression of Notch1, DLL4, IL-10, IL-17, RORγt, and Foxp3 as well as the imbalanced CD4/CD8 and Th17/Treg ratios. By contrast, inhibition of Notch signaling by DAPT can efficiently decrease Th17 cell response, downregulate the expression of Notch1, DLL4, IL-17 and the transcription of RORγt, reduce Th17 levels and restore the CD4/CD8, Th17/Treg balance. Moreover, DAPT can also inhibit Th17 cell differentiation in healthy rats, though the inhibitory capacity of Th17, Treg differentiation is less than that in EAU rats. Overall, Notch signaling activation can lead to the disturbed Th17/Treg balance in uveitis, whereas inhibition of Notch signaling can ameliorate the inflammatory response and may be a potential immunoregulatory strategy in patients with uveitis.
葡萄膜炎是全球范围内最常见的致盲性眼病之一,也是炎症性眼病的最常见病因。辅助性 T 细胞 17(Th17)和调节性 T(Treg)细胞是免疫反应的关键介质。Notch 信号通路可以调节细胞分化,在疾病的发病机制中发挥作用。在这项研究中,我们测量了实验性自身免疫性葡萄膜炎(EAU)大鼠体外淋巴结、脾脏和眼组织 T 细胞中 Notch1、DLL4、IL-10、IL-17、RORγt 和 Foxp3 的表达水平,确定了 CD4/CD8 和 Th17/Treg 的比值。此外,我们还研究了 Notch 信号通路抑制剂 N-(N-(3,5-二氟苯乙酰基)-L-丙氨酰基)-S-苯甘氨酸叔丁酯(DAPT)对 Notch1、DLL4 表达以及 Th17、Treg 细胞分化的影响。结果表明,葡萄膜炎的发病机制伴随着 Notch1、DLL4、IL-10、IL-17、RORγt 和 Foxp3 的表达升高,以及 CD4/CD8 和 Th17/Treg 比值的失衡。相反,DAPT 抑制 Notch 信号通路可以有效地减少 Th17 细胞反应,下调 Notch1、DLL4、IL-17 和 RORγt 的转录,降低 Th17 水平,并恢复 CD4/CD8、Th17/Treg 平衡。此外,DAPT 还可以抑制健康大鼠 Th17 细胞的分化,尽管其对 Th17、Treg 分化的抑制作用小于 EAU 大鼠。总之,Notch 信号通路的激活可导致葡萄膜炎中 Th17/Treg 平衡失调,而抑制 Notch 信号通路可能是葡萄膜炎患者潜在的免疫调节策略。