脂多糖及IL-1β诱导人肾小管上皮细胞hBD-2表达及抗菌活性研究

The expression of hBD-2 induced by LPS and IL-1β in human tubular epithelial cells and its antimicrobial activity

目的观察脂多糖(1ipopolyssac-chafide,LPS)及促炎症细胞因子IL-1β诱导人肾小管上皮细胞株(HK-2)β防御素-2(hBD-2)的表达及抗菌活性,探索肾脏的先天性防御病原体机制。方法给予不同质量浓度的LPS(0.1、1、10μg/ml)及IL-1β(0.1、1、10 ng/ml)刺激HK-2细胞12 h,采用实时荧光定量PCR检测HK-2细胞hBD-2 mRNA的表达,Western印迹及ELISA法检测hBD-2蛋白的表达。菌落计数法检测细胞上清对尿路致病性大肠杆菌(UTI89)和克雷白杆菌(TOP52)临床分离株的抗菌效果。结果1)HK-2细胞有微量hBD-2 mRNA表达,不同质量浓度的LPS、IL-1β刺激HK-2细胞后,hBD-2 mRNA表达呈剂量依赖性,与对照组比较差异具有统计学意义(P<0.01);2)不同质量浓度LPS及IL-1β刺激细胞后,均可诱导HK-2细胞分泌hBD-2,并在该实验质量浓度范围内呈剂量依赖性,与对照组比较差异具有统计学意义(P<0.05);3)1μg/ml的LPS及1 ng/ml的IL-1β刺激HK-2细胞12 h后,细胞浆中均可见hBD-2蛋白表达;4)LPS(1μg/ml)及IL-1β(1 ng/ml)刺激HK-2细胞24 h后的细胞上清对UTI89和TOP52有杀菌作用。结论一定剂量的LPS及前炎症细胞因子可诱导HK-2细胞hBD-2表达,hBD-2的表达可能是肾小管最初防御反应,起着发挥防御病原微生物及免疫重要作用。

[Abstract] This study designed to detect the expression of human βdefensin-2 （hBD-2） induced by LPS and IL-1β in the human tubular epithelial cell（HK-2）and its antimicrobial activity. HK-2 cells were stimulated with LPS at different concentrations （0.1, 1, 10 p.g/ml） and IL-1β at different concentrations （0.1, 1, 10 ng/ml）, respectively. 12 hours later, we detected the expression of hBD-2 mRNA in HK-2 cells by SYBR using Green fluorescent quantitative real-time PCR; hBD-2 peptide expression was also detected by Western blotting and the concentration of hBD-2 in supernatants was measured by ELISA. The antimicrobial activity of hBD-2 was assessed by colony-forming unit （CFU） assay. We found that hBD-2 mRNA could be detected in normal human tubular epithelial cells HK-2 and the expression of hBD-2 mRNA was positively related with concentration of stimulators LPS and IL-1β. The hBD-2 protein could be detected in cell supernatants and cytoplasm at 12 h after stimulation with LPS and IL-1β. At the same time, hBD-2 in supernatants showed antimicrobial activity. We concluded that LPS and pro-inflammatory factors can induce the expression of hBD-2 in a dose-dependent manner, and the expression of hBD-2 mac be an initial host defense a^ainst inflammatory stimulation in renal.