Toll-like receptor 2-mediated expression of β-defensin-2 in human corneal epithelial cells
Toll-like receptor 2-mediated expression of β-defensin-2 in human corneal epithelial cells
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DOI：
10.1016/j.micinf.2005.07.006
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发表时间：
2006-02-01
影响因子：
5.8
通讯作者：
Yu, FSX
中科院分区：
文献类型：
--
作者：
Kumar, A;Zhang, J;Yu, FSX
我们之前表明，人角膜上皮细胞（HCEC）表达Toll样受体（TLR），该受体识别革兰氏阳性细菌，并通过表达和分泌促炎细胞因子和β-防御素-2（hBD2）对金黄色葡萄球菌感染做出反应。在这项研究中，我们进一步阐明了调节 hBD-2 表达的潜在机制及其在 HCEC 响应金黄色葡萄球菌攻击的先天防御中的作用。将 HUCL 细胞（端粒酶永生化 HCEC 系）暴露于金黄色葡萄球菌、其外产物（1:10 稀释）或合成脂肽 Pam3Cys（10 μg/ml）会导致 hBD-2 上调，但不会上调 hBD1 和 hBD3。与 HUCL 细胞类似，原代 HCEC 通过表达 hBD2 mRNA 并将 hBD2 分泌到培养基中来响应金黄色葡萄球菌外产物和 Pam(3)Cys 攻击。此外，这些刺激诱导 TLR2 在 mRNA 和蛋白质水平上的表达。与其作为主要模式识别受体的作用一致，TLR2 通过细胞表面生物素化位于细胞表面。用 TLR2 中和抗体处理 HUCL 细胞导致 Pam3Cys 诱导的 hBD2 产生以及 IL-6、IL-8 和 TNF-α 分泌显着减少。 Pam3Cys 诱导的 hBD2 表达被 NF-κ B 抑制剂完全阻断，并被 p38 MAP 激酶和 JNK 抑制剂部分抑制。源自用金黄色葡萄球菌外产物或 Pam(3)Cys 攻击的 HCEC 的条件培养基对金黄色葡萄球菌、铜绿假单胞菌和大肠杆菌表现出抗菌活性。这些发现表明，金黄色葡萄球菌通过 HCEC 中 TLR2 介导的途径诱导 hBD2 产生，并且受病原体攻击、TLR 激活的 HCEC 具有抗菌活性。因此，上皮可能通过直接杀死角膜中的细菌，在抵抗细菌感染的先天防御中发挥作用。 (c) 2005 年爱思唯尔 SAS。版权所有。
We previously showed that human corneal epithelial cells (HCECs) express Toll-like receptors (TLRs), which recognize Gram-positive bacteria and respond to Staphylococcus aureus infection by the expression and secretion of proinflammatory cytokines and beta-defensin-2 (hBD2). In this study, we further elucidated the underlying mechanisms regulating hBD-2 expression and its role in innate defense in HCECs in response to S. aureus challenge. Exposure of HUCL cells, a telomerase-immortalized HCEC line, to S. aureus, its exoproducts (1:10 dilution), or synthetic lipopeptide Pam3Cys (10 mu g/ml) resulted in the up-regulation of hBD-2, but not hBD1 and hBD3. Similar to HUCL cells, primary HCECs responded to S. aureus-exoproducts and Pam(3)Cys challenge by expressing hBD2 mRNA and secreting hBD2 into the culture media. Furthermore, these stimuli induced the expression of TLR2 at both mRNA and protein levels. Consistently with its role as a major pattern- recognizing receptor, TLR2 was located at the cell surface by cell surface biotinylation. The treatment of HUCL cells with TLR2 neutralizing antibody resulted in a significant decrease in Pam3Cys-induced hBD2 production as well as IL-6, IL-8, and TNF-alpha secretion. The Pam3Cys-induced hBD2 expression was completely blocked by NF-kappa B inhibitors and partially inhibited by p38 MAP kinase and the JNK inhibitors. Conditioned media derived from HCECs challenged with S. aureus-exoproducts or Pam(3)Cys exhibited antibacterial activity against S. aureus, Pseudomonas aeruginosa and Escherichia coli. These findings suggest that S. aureus induces hBD2 production through TLR2-mediated pathways in HCECs and that pathogen-challenged, TLR-activated HCECs possess antimicrobial activity. Thus, the epithelium might play a role in innate defense against bacterial infection by directly killing bacteria in the cornea. (c) 2005 Elsevier SAS. All rights reserved.