A study on the expression of cytokines in epithelial cells stimulated with LPS.

本研究旨在探讨脂多糖(LPS)刺激口腔和肠上皮细胞可诱导何种细胞因子的产生，以及LPS对口腔和肠上皮细胞分泌成分(SC)的调节作用。结果如下：1)LPS刺激粘膜上皮细胞可诱导IL-1、IL-6、IL-8、转化生长因子-β和肿瘤坏死因子-α的基因表达。内毒素刺激的内皮细胞SC基因表达呈时间依赖性增加，72小时达平台期。内皮细胞经内毒素刺激后24小时SC蛋白产生增加，72小时达平台期。培养72小时，上皮细胞产生的SC蛋白为MUG/ml。然而，低剂量的内毒素刺激上皮细胞，并不增加SC的mRNA和蛋白表达。LPS刺激后，两种上皮细胞均表达CD14、CD11b、CD11c和PAF受体的mRNA，这些结果提示上皮细胞通过增加细胞因子和SC的产生而参与机体的防御。此外，上皮细胞中内毒素受体的存在提示了内毒素的信号转导途径。

The purpose of this study is to examine what kinds of cytokines can be induced in the oral and intestinal epithelial cells stimulated with lipopolysaccharide (LPS), and how is the secretory component (SC), a receptor for polymeric IgA,constitutively expressed on the epithelial cells regulated by LPS.The results obtained were as follows ;1) Stimulation of mucosal epithelial cells by LPS resulted in the mRNA expression for IL-1, IL-6, IL-8, TGF-beta and TNF-alpha at 12 hours.2). Expression of SC mRNA in the epithelial cells stimulated with LPS increased at a time-dependent manner and reached plateau at 72 hours.3). Epithelial cells stimulated with LPS increased the production of SC protein at 24 hours and reached plateau at 72 hours. The mug/ml of SC protein was produced by epithelial cells at 72 hours. However, stimulation of epithelial cells by a low dose of LPS resulted in no increase of SC mRNA and protein.4). Both epithelial cells expressed mRNA for CD14, CD11b, CD11c and PAF receptor after stimulation of LPS.From these results, epithelial cells are contributed to the defense of body through increased production of cytokines and SC.Moreover, the presence of LPS receptor in the epithelial cell suggested the signal transduction pathway for LPS.