Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong Province, China.
Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong Province, China.
Cell Signal. 2018 Sep;49:39-45. doi: 10.1016/j.cellsig.2018.05.007. Epub 2018 May 24.
Interleukin (IL)-32, a novel cytokine, participates in a variety of inflammatory disorders. Thymic stromal lymphopoietin (TSLP) plays important roles in mucosal epithelial cells, especially in allergy-induced inflammation, through the TSLP-TSLPR (thymic stromal lymphopoietin receptor) signalling pathway. However, the association of IL-32 with TSLP on the ocular surface remains unclear. The present work aimed to assess the functional association of IL-32 with TSLP in the control of pro-inflammatory cytokine levels in the corneal epithelium. Human corneal tissue specimens and human corneal epithelial cells (HCECs) were administered different concentrations of IL-32 in the presence or absence of various inhibitors to assess TSLP levels and localization, as well as the molecular pathways that control pro-inflammatory cytokine production. TSLP mRNA levels were determined by real time RT- PCR, while protein levels were quantitated by ELISA and immunohistochemical staining. TSLP protein expression was examined in donor corneal epithelium samples. IL-32 significantly upregulated TSLP and pro-inflammatory cytokines (TNFα and IL-6) in HCECs at the gene and protein levels. The production of pro-inflammatory molecules by IL-32 was increased by recombinant TSLP. Interestingly, both NF-κB (quinazoline) and caspase-1 (VX-765) inhibitors suppressed the IL-32-related upregulation of pro-inflammatory cytokines (TNFα and IL-6). These findings demonstrate that IL-32 and IL-32-induced-TSLP are critical cytokines that participate in inflammatory responses through the caspase-1 and NF-κB signalling pathways in the corneal epithelium, suggesting new molecular targets for inflammatory diseases of the ocular surface. The effects of IL-32 on cell proliferation and apoptosis were investigated by MTT assays and RT-PCR,respectively. The results demonstrated that IL-32 inhibits cells apoptosis in HCECs.
白细胞介素 (IL)-32 是一种新型细胞因子，参与多种炎症性疾病。胸腺基质淋巴细胞生成素 (TSLP) 通过 TSLP-TSLPR（胸腺基质淋巴细胞生成素受体）信号通路在黏膜上皮细胞中发挥重要作用，特别是在过敏引起的炎症中。然而，IL-32 与眼表面的 TSLP 的关联尚不清楚。本研究旨在评估 IL-32 与 TSLP 在控制角膜上皮细胞中促炎细胞因子水平方面的功能关联。用人角膜组织标本和人角膜上皮细胞（HCEC）在不同浓度的 IL-32 存在或不存在不同抑制剂的情况下，评估 TSLP 水平和定位，以及控制促炎细胞因子产生的分子途径。通过实时 RT-PCR 测定 TSLP mRNA 水平，通过 ELISA 和免疫组织化学染色定量测定蛋白水平。检查供体角膜上皮组织样本中的 TSLP 蛋白表达。IL-32 在 HCEC 中显著上调 TSLP 和促炎细胞因子（TNFα 和 IL-6）的基因和蛋白水平。重组 TSLP 增加了促炎分子的产生。有趣的是，NF-κB（喹唑啉）和 caspase-1（VX-765）抑制剂均抑制了 IL-32 相关的促炎细胞因子（TNFα 和 IL-6）的上调。这些发现表明，IL-32 和 IL-32 诱导的 TSLP 是通过角膜上皮细胞中的 caspase-1 和 NF-κB 信号通路参与炎症反应的关键细胞因子，为眼表面炎症性疾病提供了新的分子靶点。通过 MTT 测定和 RT-PCR 分别研究了 IL-32 对细胞增殖和凋亡的影响。结果表明，IL-32 抑制 HCEC 细胞凋亡。
