IL-13对成纤维细胞IL-13受体和IL-4受体表达的影响

目的研究IL-13对人肺成纤维细胞株HFL-1和人肝星状细胞株LX-2 IL-13受体和IL-4受体表达的调节作用。方法 RT-PCR法检测HFL-1细胞株和LX-2细胞株IL-13Rα1、IL-4R和IL-13Rα2 mRNA的表达;凝胶电泳定量软件Image Tool2.0对RT-PCR电泳条带进行光密度分析;ELISA法检测HFL-1细胞株和LX-2细胞株分泌可溶型IL-13Rα2以及检测细胞裂解液总IL-13Rα1、IL-4R和IL-13Rα2含量。结果 IL-13(5～100 ng/ml)对HFL-1细胞株和LX-2细胞株表达IL-13Rα1和IL-4R无影响;IL-13为5、10、20 ng/ml时能诱导HFL-1细胞株表达IL-13Rα2并呈现剂量依赖,当IL-13为50 ng/ml时,对HFL-1细胞株IL-13Rα2表达的诱导作用明显减弱,IL-13 100 ng/ml组没有检测到HFL-1细胞株IL-13Rα2的表达;LX-2细胞株IL-13Rα2表达缺失且IL-13不能诱导LX-2细胞株表达IL-13Rα2。结论 IL-13不能上调人肺成纤维细胞株HFL-1和人肝星状细胞株LX-2表达功能型受体IL-13Rα1和IL-4R,表明IL-13不能通过上调IL-13Rα1和IL-4R表达量来放大自身作用;一定浓度的IL-13能诱导人肺成纤维细胞株HFL-1表达抑制型受体IL-13Rα2,表明IL-13的自身负调控。

The effects of IL-13 on the expressions of IL-13 receptors and IL-4 receptor in fibroblasts

Cytokine interleukin-13(IL-13) is critical for organ fibrosis.IL-13 receptor alpha 1(IL-13Rα1) and IL-4 receptor(IL-4R) form a functional IL-13 receptor complex that is thought to mediate most IL-13-induced effects.However,IL-13 receptor alpha 2(IL-13Rα2),the high affinity receptor for IL-13,is thought to act as a decoy receptor for IL-13.This study aimed to investigate whether the fibrosis-related fibroblast could express IL-13Rα1,IL-4R or IL-13Rα2 and whether IL-13 could regulate the expressions of these receptors.The expressions of IL-13Rα1,IL-4R and IL-13Rα2 mRNA were detected by RT-PCR in human lung fibroblast line HFL-1 and human hepatic stellate cell line LX-2.The luminous intensity of RT-PCR electrophoresis strips was analyzed by gel quantitative software Image Tool 2.0.The expressions of soluble IL-13Rα2,total IL-13Rα1,IL-4R and IL-13Rα2 were measured by ELISA in the supernatant or lysate of HFL-1 cells and LX-2 cells.We found that IL-13(5 to 100 ng/ml) had no effect on the expressions of IL-13Rα1 and IL-4R in HFL-1 cells and LX-2 cells.IL-13Rα2 expression of HFL-1 cells was induced in dose-dependent manner under the circumstance of low concentrations of 5 to 20 ng/ml IL-13.However,IL-13Rα2 expression of HFL-1 cells was significantly decreased by using 50 ng/ml of IL-13 as compare with 20 ng/ml of IL-13 group,and could not be induced by using 100 ng/ml of IL-13.On the other hand,IL-13Rα2 expression was not found in LX-2 cells and the stimulation of IL-13 could not induce its expression.These results demonstrate that IL-13 can not up-regulate the expression of IL-13Rα1 and IL-4R,a functional IL-13 receptor complex,in human lung fibroblast line HFL-1and human hepatic stellate cell line LX-2,indicating that IL-13 can not enlarge their own function by means of increasing IL-13Rα1 and IL-4R expressions.The results also show that certain concentrations of IL-13 can induce the expression of IL-13Rα2,an inhibitory IL-13 receptor,in human lung fibroblast line HFL-1 that implicates an unexpected mechanism of negative regulation of IL-13 by itself.