Schepens Eye Research Institute/Massachusetts Eye and Ear and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America ; Centre for Molecular Biosciences, University of Ulster, Coleraine, N. Ireland.
PLoS One. 2013 Sep 10;8(9):e74010. doi: 10.1371/journal.pone.0074010. eCollection 2013.
The conjunctiva is a moist mucosal membrane that is constantly exposed to an array of potential pathogens and triggers of inflammation. The NACHT, leucine rich repeat (LRR), and pyrin domain-containing protein 3 (NLRP3) is a Nod-like receptor that can sense pathogens or other triggers, and is highly expressed in wet mucosal membranes. NLRP3 is a member of the multi-protein complex termed the NLRP3 inflammasome that activates the caspase 1 pathway, inducing the secretion of biologically active IL-1β, a major initiator and promoter of inflammation. The purpose of this study was to: (1) determine whether NLRP3 is expressed in the conjunctiva and (2) determine whether goblet cells specifically contribute to innate mediated inflammation via secretion of IL-1β. We report that the receptors known to be involved in the priming and activation of the NLRP3 inflammasome, the purinergic receptors P2X4 and P2X7 and the bacterial Toll-like receptor 2 are present and functional in conjunctival goblet cells. Toxin-containing Staphylococcus aureus (S. aureus), which activates the NLRP3 inflammasome, increased the expression of the inflammasome proteins NLRP3, ASC and pro- and mature caspase 1 in conjunctival goblet cells. The biologically active form of IL-1β was detected in goblet cell culture supernatants in response to S. aureus, which was reduced when the cells were treated with the caspase 1 inhibitor Z-YVAD. We conclude that the NLRP3 inflammasome components are present in conjunctival goblet cells. The NRLP3 inflammasome appears to be activated in conjunctival goblet cells by toxin-containing S. aureus via the caspase 1 pathway to secrete mature IL1-β. Thus goblet cells contribute to the innate immune response in the conjunctiva by activation of the NLRP3 inflammasome.
结膜是一种湿润的黏膜膜，不断暴露于一系列潜在的病原体和炎症触发物中。NACHT、富含亮氨酸重复（LRR）和吡咯啉域蛋白 3（NLRP3）是一种核苷酸结合寡聚化结构域样受体（Nod-like receptor），可以感知病原体或其他触发物，并且在湿润的黏膜膜中高度表达。NLRP3 是一种多蛋白复合物的成员，称为 NLRP3 炎性小体，该复合物激活半胱氨酸蛋白酶 1 途径，诱导生物活性 IL-1β 的分泌，IL-1β 是炎症的主要起始和促进剂。本研究的目的是：（1）确定 NLRP3 是否在结膜中表达；（2）确定杯状细胞是否通过分泌 IL-1β 特异性参与固有介导的炎症。我们报告说，已知参与 NLRP3 炎性小体的启动和激活的受体，嘌呤能受体 P2X4 和 P2X7 以及细菌 Toll 样受体 2 存在于结膜杯状细胞中并且具有功能。含有毒素的金黄色葡萄球菌（S. aureus）激活 NLRP3 炎性小体，增加了结膜杯状细胞中炎性小体蛋白 NLRP3、ASC 和前体和成熟半胱氨酸蛋白酶 1 的表达。在响应 S. aureus 时，在杯状细胞培养上清液中检测到生物活性形式的 IL-1β，当用半胱氨酸蛋白酶 1 抑制剂 Z-YVAD 处理细胞时，其表达减少。我们得出结论，NLRP3 炎性小体成分存在于结膜杯状细胞中。NRLP3 炎性小体似乎通过半胱氨酸蛋白酶 1 途径被含毒素的 S. aureus 在结膜杯状细胞中激活，以分泌成熟的 IL1-β。因此，杯状细胞通过激活 NLRP3 炎性小体为结膜中的固有免疫反应做出贡献。
