Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China.
Department of Ophthalmology, the Affiliated Hospital of Xuzhou Medical College, Xuzhou, 221000, Jiangsu Province, China.
BMC Ophthalmol. 2015 Jun 3;15:55. doi: 10.1186/s12886-015-0041-z.
Fungal keratitis is a kind of intractable and sight-threatening diseases. Spleen-tyrosine kinase (Syk) is a non-receptor tyrosine kinase, which plays an important role in the signaling pathway of the receptors. In the current study, we investigate the expression and function of Syk in human corneal epithelial cells with Aspergillus fumigatus (A. fumigatus) infection.
Cultured telomerase-immortalized human corneal epithelial cells (THCEs) were treated with A. fumigatus hyphae with or without treatment of Syk inhibitors. Activation of Syk and the role of Syk in regulating inflammatory cytokines and chemokines expression were evaluated. The mRNA expression was determined by real time PCR, and protein activation was measured by western blotting.
Syk protein was detected in THCEs, and its activation was enhanced after treatment of A. fumigatus hyphae. Expression of inflammatory cytokines (IL-1β and IL-6) and chemokines (IL-8 and CXCL1) mRNA were significantly increased after stimulation of A. fumigatus hyphae in THCEs. Activation of Syk and expression of IL-1β, IL-6, IL-8 and CXCL1 by A. fumigatus hyphae were blocked by Syk inhibitors.
These findings demonstrate that normal human corneal epithelial cells produce Syk, and Syk activation plays an important role in regulating A. fumigatus hyphae-induced inflammatory responses in THCEs.
真菌性角膜炎是一种难治性、致盲性眼病。脾酪氨酸激酶（Syk）是一种非受体酪氨酸激酶，在受体信号通路中发挥重要作用。本研究旨在探讨 Aspergillus fumigatus（A. fumigatus）感染人角膜上皮细胞中 Syk 的表达和功能。
用 A. fumigatus 菌丝处理或不处理 Syk 抑制剂培养永生化人角膜上皮细胞（THCE）。评估 Syk 的激活及其在调节炎症细胞因子和趋化因子表达中的作用。通过实时 PCR 测定 mRNA 表达，通过 Western blot 测定蛋白激活。
在 THCE 中检测到 Syk 蛋白，A. fumigatus 菌丝处理后其激活增强。A. fumigatus 菌丝刺激后 THCE 中炎症细胞因子（IL-1β和 IL-6）和趋化因子（IL-8 和 CXCL1）mRNA 的表达显著增加。Syk 抑制剂阻断了 Syk 的激活以及 A. fumigatus 菌丝诱导的 IL-1β、IL-6、IL-8 和 CXCL1 的表达。
这些发现表明，正常的人角膜上皮细胞产生 Syk，Syk 的激活在调节 A. fumigatus 菌丝诱导的 THCE 炎症反应中起重要作用。
