细菌脂多糖经p38丝裂原激活蛋白激酶通路调节claudin-11基因的表达

Involvement of p38 MAPK in the up-regulation of claudin-11 by lipopolysaccharide

目的阐明细菌内毒素细菌脂多糖(lipopolysaccharide,LPS)是否影响紧密连接蛋白claudin-11的表达及其分子机制。方法表达claudin-11基因的原代培养人皮肤成纤维细胞,加入纯化的LPS或核转录因子κB(NF-κB)特异性抑制剂MG132或p38丝裂原活化蛋白激酶(p38MAPK)抑制剂SB203580后,利用逆转录-聚合酶链反应(RT-PCR)和蛋白免疫印迹方法检测claudin-11基因mRNA和蛋白质表达水平变化,利用细胞免疫荧光染色法检测NF-κB核转移。结果LPS细胞膜受体TLR4在人皮肤成纤维细胞表达;2μg/ml LPS能提高claudin-11基因mRNA和蛋白质的表达水平。进一步研究发现:虽然LPS能使NF-κB从细胞质转移到细胞核,但LPS引起claudin-11基因表达增加不能被NF-κB特异性抑制剂MG132抑制,而能被p38丝裂原活化蛋白激酶(p38MAPK)抑制剂SB203580明显抑制。结论细菌内毒素LPS影响claudin-11基因的表达可能是通过p38 MAPK通路来调节的。

Objective To analysis if the expression of claudin-11 was affected by lipopolysaccharide （LPS） and explore its related mechanism. Methods Human dermal primary fibroblasts expressing claudin-11 gene were treated with LPS or MG132 （a specific inhibitor of NFκB） or SB203580 （a specific inhibitor of p38 mitogen-activated protein kinases （p38MAPK）. RT-PCR and Western blotting were used to detect mRNA and protein expression levels of claudin-11 respectively. NFκB nuclear transloeation in the fibroblasts was detected by cell immunostaining. Results LPS receptor TLR4 mRNA was detected in the cultured human dermal primary fibroblasts. The levels of clandin-11 mRNA and protein in 2 μg/ml LPS treated group were significantly increased compared with the control. The up-regulation of clandin-11 expression induced by LPS was inhibited not by MG132, but by SB203580, although LPS induced NFκB translocation from cytoplasm to nuclear. Conclusion LPS up-regulated the expression of clandin-11 mediated by p38 MAPK pathway.