Shirasaki Hideaki, Kanaizumi Etsuko, Seki Nobuhiko, Himi Tetsuo
Department of Otolaryngology, Sapporo Medical University, School of Medicine, Hokkaido, Japan.
Department of Otolaryngology, Sapporo Medical University, School of Medicine, Hokkaido, Japan.
Allergol Int. 2015 Apr;64(2):169-74. doi: 10.1016/j.alit.2014.11.002. Epub 2015 Jan 13.
Hypersecretion of mucin in the airway epithelium is an important feature of allergic airway diseases. Of the 3 cysteinyl leukotrienes (CysLTs; LTC4 LTD4 and LTE4), only LTE4 is sufficiently stable to be detectable in extracellular fluids. However, LTE4 has received little attention because it binds poorly to the CysLT1 and CysLT2 receptors; therefore, little is known about the effects of LTE4 on mucous secretion. Recently, studies have focused on the P2Y12 receptor as a potential receptor for LTE4, because this receptor is required for LTE4-mediated pulmonary inflammation. In our previous study, we confirmed the expression of P2Y12 receptor in human airway epithelial cells. To clarify the roles of LTE4 in airway epithelial cells, we investigated mucus secretion by LTE4 in vitro.
Confluent NCI-H292 cells were stimulated with LTE4 (0.01-1 μM) for 24 h. The release and production of MUC5AC protein, a gel-forming mucin, were evaluated with an enzyme-linked immunosorbent assay.
Western blot analysis revealed that NCI-H292 cells expressed P2Y12 receptor protein. LTE4 significantly induced the release of MUC5AC mucin in a dose-dependent manner. Th2 cytokines such as IL-4 (10 ng/mL) and IL-13 (10 ng/mL) accelerated the LTE4-induced release of MUC5AC protein. MRS2935, a P2Y12 receptor antagonist, partially inhibited the LTE4-induced release of MUC5AC protein in the airway. In contrast, MK571, a CysLT1 receptor antagonist, did not affect the release of MUC5AC protein elicited by LTE4.
These results suggest that LTE4 may play some important roles in allergic mucus secretion partially via activation of P2Y12 receptor.
气道上皮细胞中粘蛋白的过度分泌是过敏性气道疾病的一个重要特征。在三种半胱氨酰白三烯（CysLTs；LTC4、LTD4和LTE4）中，只有LTE4足够稳定，能够在细胞外液中被检测到。然而，LTE4很少受到关注，因为它与CysLT1和CysLT2受体的结合能力较差；因此，关于LTE4对粘液分泌的影响知之甚少。最近，研究集中在P2Y12受体作为LTE4的潜在受体，因为该受体是LTE4介导的肺部炎症所必需的。在我们之前的研究中，我们证实了P2Y12受体在人气道上皮细胞中的表达。为了阐明LTE4在气道上皮细胞中的作用，我们在体外研究了LTE4诱导的粘液分泌。
用LTE4（0.01 - 1 μM）刺激汇合的NCI-H292细胞24小时。用酶联免疫吸附测定法评估凝胶形成粘蛋白MUC5AC蛋白的释放和产生。
蛋白质印迹分析显示NCI-H292细胞表达P2Y12受体蛋白。LTE4以剂量依赖性方式显著诱导MUC5AC粘蛋白的释放。Th2细胞因子如IL-4（10 ng/mL）和IL-13（10 ng/mL）加速了LTE4诱导的MUC5AC蛋白释放。P2Y12受体拮抗剂MRS2935部分抑制了LTE4诱导的气道中MUC5AC蛋白的释放。相比之下，CysLT1受体拮抗剂MK571不影响LTE4引起的MUC5AC蛋白释放。
这些结果表明，LTE4可能通过部分激活P2Y12受体在过敏性粘液分泌中发挥一些重要作用。
