Alternaria extract activates autophagy that induces IL-18 release from airway epithelial cells.
Alternaria extract activates autophagy that induces IL-18 release from airway epithelial cells.
复制标题
链格孢提取物激活自噬，诱导气道上皮细胞释放 IL-18。
DOI：
10.1016/j.bbrc.2015.05.076
复制
发表时间：
2015-09-04
影响因子：
3.1
通讯作者：
Ohshima Y
中科院分区：
文献类型：
--
作者：
Murai H;Okazaki S;Hayashi H;Kawakita A;Hosoki K;Yasutomi M;Sur S;Ohshima Y
链格孢 (Alternaria alternata) 是一种主要的室外过敏原，可引起过敏性气道疾病。链格孢提取物 (ALT-E) 已被证明可诱导气道上皮细胞释放 IL-18，从而启动 Th2 型反应。我们研究了 ALT-E 刺激的气道上皮细胞释放 IL-18 的潜在机制。在不同的自噬或半胱天冬酶抑制剂存在下，用 ALT-E 刺激正常人支气管上皮细胞和 A549 人肺腺癌细胞。通过 ELISA 测量培养物上清液中的 IL-18 水平。通过免疫荧光染色和免疫印迹测定自噬体的数量、LC3-I 到 LC3-II 的转换以及 p62 降解。 3-甲基腺嘌呤和巴弗洛霉素分别抑制自噬体前结构和自溶酶体的形成，抑制 ALT-E 诱导的细胞释放 IL-18，而 caspase 1 和 8 抑制剂则不然。 ALT-E 刺激增加气道上皮细胞中自噬体的形成、LC-3 转化和 p62 降解。 LPS 刺激诱导 A549 细胞中 LC3 转化，但不诱导 IL-18 释放或 p62 降解。与 LPS 不同，ALT-E 诱导气道上皮细胞通过自噬依赖性、半胱天冬酶 1 和 8 独立途径释放 IL-18。尽管自噬已被证明可以负向调节 TLR 刺激的巨噬细胞中的典型炎症小体活性，但我们的数据表明该过程是气道上皮细胞分泌 IL-18 的一种非常规机制。
Alternaria alternata is a major outdoor allergen that causes allergic airway diseases. Alternaria extract (ALT-E) has been shown to induce airway epithelial cells to release IL-18 and thereby initiate Th2-type responses. We investigated the underlying mechanisms involved in IL-18 release from ALT-E-stimulated airway epithelial cells. Normal human bronchial epithelial cells and A549 human lung adenocarcinoma cells were stimulated with ALT-E in the presence of different inhibitors of autophagy or caspases. IL-18 levels in culture supernatants were measured by ELISA. The numbers of autophagosomes, an LC3-I to LC3-II conversion, and p62 degradation were determined by immunofluorescence staining and immunoblotting. 3-methyladenine and bafilomycin, which inhibit the formation of preautophagosomal structures and autolysosomes, respectively, suppressed ALT-E-induced IL-18 release by cells, whereas caspase 1 and 8 inhibitors did not. ALT-E-stimulation increased autophagosome formation, LC-3 conversion, and p62 degradation in airway epithelial cells. LPS-stimulation induced the LC3 conversion in A549 cells, but did not induce IL-18 release or p62 degradation. Unlike LPS, ALT-E induced airway epithelial cells to release IL-18 via an autophagy dependent, caspase 1 and 8 independent pathway. Although autophagy has been shown to negatively regulate canonical inflammasome activity in TLR-stimulated macrophages, our data indicates that this process is an unconventional mechanism of IL-18 secretion by airway epithelial cells.