Wang Shao-Hung, Wang Shou-Chieh, Chen Pei-Ching, Wang Shou-Tsung, Liu Yi-Wen
Department of Microbiology, Immunology and Biopharmaceuticals; College of Life Sciences, National Chiayi University, Chiayi 600, Taiwan.
Division of Nephrology, Department of Internal Medicine, Kuang Tien General Hospital, Taichung 437, Taiwan.
Med Mycol. 2017 Apr 1;55(3):314-322. doi: 10.1093/mmy/myw082.
In the present data, we found that Candida albicans (C. albicans) caused bladder epithelial cell morphology alteration, cell damage, and inflammatory responses, including cyclooxygenase-2 (COX-2) gene and protein expression as well as prostaglandin E2 accumulation. In addition, the molecular pathway underlying C. albicans-induced urothelial COX-2 gene expression was examined. Among MAPK pathways, phosphorylation of ERK1/2, p38, and JNK each increased following C. albicans infection for 12 h. However, C. albicans-induced COX-2 protein expression was inhibited by specific inhibitors of ERK and p38 (U0126 and SB203580) but not by JNK inhibitor SP600125. Additional evidence came from the increased amount of phosphorylated RSK that is the mutual downstream molecule of ERK1/2 and p38. Furthermore, phosphorylation of RSK protein was reduced by the ERK and p38 inhibitor, suggesting that the urothelial COX-2 gene was induced majorly though the ERK/p38-RSK pathway by C. albicans infection. We also found transcription factor CREB-1 showed increased binding to the COX-2 gene promoter by chromatin immunoprecipitation assay. Next, we used receptor inhibitors including Toll-like receptor (TLR)-Myd88 inhibitor ST2825, Dectin-Syk inhibitor Syk inhibitor, and epidermal growth factor receptor (EGFR) inhibitor PD168393 to identify which one was the main target associated with C. albicans binding. The results revealed that it was EGFR, recognized by C. albicans, that mostly mediated the ERK/p38-RSK pathway activation to induce COX-2 gene expression, but this was not the case for TLRs and Dectin receptors. In summary, these results demonstrated the EGFR-ERK/p38-RSK-CREB-1 pathway was involved significantly in the C. albicans-induced COX-2 expression in human urothelium.
在目前的数据中，我们发现白色念珠菌可导致膀胱上皮细胞形态改变、细胞损伤及炎症反应，包括环氧合酶-2（COX-2）基因和蛋白表达以及前列腺素E2蓄积。此外，还研究了白色念珠菌诱导尿路上皮COX-2基因表达的分子途径。在丝裂原活化蛋白激酶（MAPK）途径中，白色念珠菌感染12小时后，细胞外信号调节激酶1/2（ERK1/2）、p38和c-Jun氨基末端激酶（JNK）的磷酸化水平均升高。然而，ERK和p38的特异性抑制剂（U0126和SB203580）可抑制白色念珠菌诱导的COX-2蛋白表达，而JNK抑制剂SP600125则无此作用。另外，作为ERK1/2和p38共同下游分子的磷酸化核糖体S6激酶（RSK）含量增加也为该结论提供了证据。此外，ERK和p38抑制剂可降低RSK蛋白的磷酸化水平，提示白色念珠菌感染主要通过ERK/p38-RSK途径诱导尿路上皮COX-2基因表达。我们还通过染色质免疫沉淀试验发现转录因子CREB-1与COX-2基因启动子的结合增加。接下来，我们使用了包括Toll样受体（TLR）-髓样分化因子88（Myd88）抑制剂ST2825、树突状细胞相关C型凝集素-脾酪氨酸激酶（Dectin-Syk）抑制剂和表皮生长因子受体（EGFR）抑制剂PD168393在内的受体抑制剂，以确定哪一种是与白色念珠菌结合相关的主要靶点。结果显示，白色念珠菌识别的EGFR主要介导ERK/p38-RSK途径激活，从而诱导COX-2基因表达，而TLR和Dectin受体并非如此。总之，这些结果表明EGFR-ERK/p38-RSK-CREB-1途径在白色念珠菌诱导的人尿路上皮COX-2表达中起重要作用。
