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

本研究旨在探讨脂多糖（lipopolysaccharide，LPS）刺激口腔和肠上皮细胞后，可诱导哪些细胞因子的产生，以及LPS对上皮细胞分泌成分（secretory component，SC）的组成性表达的调节作用。1）用LPS刺激粘膜上皮细胞导致IL-1、IL-6、IL-8、TGF-β和TNF-α的mRNA在12小时时表达。LPS刺激后，上皮细胞SC mRNA的表达呈时间依赖性增加，72 h达到平台期。用LPS刺激的上皮细胞在24小时增加SC蛋白的产生，并在72小时达到平台。在72小时，上皮细胞产生μ g/ml的SC蛋白。而低剂量LPS刺激上皮细胞后，SC mRNA和蛋白表达无明显增加。LPS刺激后，两种上皮细胞均表达CD 14、CD 11b、CD 11 c和PAF受体mRNA，提示上皮细胞通过分泌细胞因子和SC参与机体防御，同时，上皮细胞内存在LPS受体，提示了LPS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.