MD2在内毒素激活肺泡Ⅱ型上皮细胞中的表达及作用

Expression and roles of MD2 in activation of alveolar typeⅡ cells induced by lipopolysaccharides

目的探讨髓样分化蛋白(myeloid differentiation protein-2,MD2)在内毒素(LPS)激活肺泡Ⅱ型上皮细胞(ATⅡcells)中的表达及可能作用机制。方法通过RT-PCR的方法检测MD2mRNA在ATⅡcells的表达;电泳迁移率改变法检测LPS刺激后的ATⅡcellsNF-κB活性的变化;ELISA检测ATⅡcells培养上清中TNF-α和IL-6的含量变化。结果正常ATⅡcells表达有MD2mRNA,LPS刺激后表达增强;其表达在1～103ng/mlLPS范围内呈浓度依赖性增强。LPS刺激后,ATⅡcellsNF-κB活性及TNF-α和IL-6的生成均呈浓度依赖性的增强。结论MD2在LPS激活ATⅡcells中起着重要作用。

Objective To investigate the expression and roles of myeloid differentiation protein-2（MD2） in the activation of alveolar typell epithelial cells （AT Ⅱ cells） induced by lipopolysaccharide（LPS）. Methods The expressions of MD2 mRNA in AT Ⅱ cells were detected by semi-quantitative RT-PCR. The activity of NF-κB in AT Ⅱ cells was measured with electrophoretic mobility shift assay （EMSA）. The TNF-α and IL-6 concentrations in the supernatant of cultured AT Ⅱ cells were tested with ELISA. Results The expressions of MD2 mRNA were detected in normal AT Ⅱ cells. After stimulation with LPS, the expressions increased in a dose-dependent manner in the range of 1- 10^3 ng/ml LPS. In AT 11 cells after stimulation with LPS, the NF-κB activity and the production of TNF-α and IL-6 increased in a dose-dependent manner. Conclusion MD2 play a pivotal role in the activation of AT 11 cells induced by LPS.