Wu Yang, Bu Jinghua, Yang Yiran, Lin Xiang, Cai Xiaoxin, Huang Caihong, Zheng Xiaoxiang, Ouyang Weijie, Li Wei, Zhang Xiaobo, Liu Zuguo
Eye Institute of Xiamen University and Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, Fujian, China.
Invest Ophthalmol Vis Sci. 2017 Sep 1;58(11):4898-4907. doi: 10.1167/iovs.17-22240.
To investigate the role of mitogen-activated protein kinase-activated protein kinase-2 (MK2) in ocular surface damage of dry eye.
MK2 inhibition was performed in mice subjected to desiccating stress (DS) by topical application of MK2 inhibitor (MK2i) or vehicle eye drops. The total and phosphorylated MK2 in conjunctiva were detected by Western blot. The phenol red cotton test was used to measure tear production, and Oregon green dextran staining was performed to assess corneal epithelial barrier function. PAS staining was used to quantify conjunctival goblet cells. Immunofluorescent staining and quantitative RT-PCR were used to assess the expression of matrix metalloproteinase (MMP)-3 and -9 in corneal epithelium. Apoptosis in ocular surface was assessed by TUNEL and immunofluorescent staining for activated caspase-3 and -8. Inflammation was evaluated by CD4+ T-cell infiltration and production of T helper (Th) cytokines, including IFN-γ, IL-13, and IL-17A in conjunctiva.
DS promoted MK2 activation in conjunctiva. Compared with vehicle control mice, MK2i-treated mice showed increased tear production, decreased goblet cell loss, and improved corneal barrier function. Topical MK2 inhibition decreased the expression of MMP-3 and -9 in corneal epithelium, and suppressed cell apoptosis in ocular surface under DS. Topical MK2 inhibition decreased CD4+ T-cell infiltration, with decreased production of IFN-γ and IL-17A and increased production of IL-13 in conjunctiva.
Topical MK2 inhibition effectively alleviated ocular surface damage via suppressing cell apoptosis and CD4+ T-cell-mediated inflammation in ocular surface of dry eye.
研究丝裂原活化蛋白激酶激活的蛋白激酶-2（MK2）在干眼眼表损伤中的作用。
通过局部应用MK2抑制剂（MK2i）或赋形剂滴眼液，对遭受干燥应激（DS）的小鼠进行MK2抑制。采用蛋白质免疫印迹法检测结膜中总MK2和磷酸化MK2。用酚红棉线试验测量泪液分泌量，并用 Oregon 绿葡聚糖染色评估角膜上皮屏障功能。采用 PAS 染色对结膜杯状细胞进行定量。用免疫荧光染色和定量 RT-PCR 评估角膜上皮中基质金属蛋白酶（MMP）-3和-9的表达。通过 TUNEL 以及活化的半胱天冬酶-3和-8的免疫荧光染色评估眼表细胞凋亡。通过结膜中CD4+T细胞浸润以及辅助性T细胞（Th）细胞因子（包括IFN-γ、IL-13和IL-17A）的产生来评估炎症反应。
DS促进结膜中MK2的激活。与赋形剂对照小鼠相比，MK2i处理的小鼠泪液分泌增加，杯状细胞丢失减少，角膜屏障功能改善。局部抑制MK2可降低角膜上皮中MMP-3和-9的表达，并抑制DS条件下眼表细胞凋亡。局部抑制MK2可减少结膜中CD4+T细胞浸润，降低IFN-γ和IL-17A的产生，并增加IL-13的产生。
局部抑制MK2可通过抑制干眼眼表细胞凋亡和CD4+T细胞介导的炎症反应有效减轻眼表损伤。
