八肽胆囊收缩素对肿瘤坏死因子-α诱导的大鼠滑膜细胞株RSC-364活化蛋白-1活性和JunB表达的影响

Influence of cholecystokinin octapeptide on activator protein-1 binding activity and JunB expression in rat synoviai cell strain RSC-364 induced with tumor necrosis factor-α

目的研究八肽胆囊收缩素(cholecystokinin octapeptide,CCK-8)对肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)诱导的大鼠滑膜细胞株RSC-364活化蛋白-1(activator protein-1,AP-1)活性和JunB表达的影响。方法分别采用凝胶迁移试验、Western blot法和RT-PCR法检测CCK-8对TNF-α诱导RSC-364细胞中AP-1活性、JunB蛋白表达和JunB基因mRNA水平的影响。结果 TNF-α可激活RSC-364细胞中AP-1,CCK-8对其具有抑制作用。静息的RSC-364细胞中JunB蛋白表达很少;经TNF-α处理2 h,JunB表达增加,而CCK-8对TNF-α的上述效应具有明显的促进作用;FsK(一种cAMP诱导剂)与CCK-8作用类似,对TNF-α的上述效应亦有促进作用;CR1409(CCK-A受体)、CR2945(CCK-B受体结抗剂)和H89(PKA特异性抑制剂)均可部分逆转CCK-8的上述作用。CCK-8可促进TNF-α引起JunB基因mRNA表达的增加。结论 CCK-8引起AP-1活性降低,促进TNF-α诱导JunB蛋白和基因表达增加,该作用是由CCK-A受体和CCK-B受体共同介导的,cAMP/PKA通路可能参与其信号转导途径。

Objective To investigate the influence of cholecystokinin octapeptide （CCK-8） on the activator protein （AP）-I binding activity and JunB expression in rat synoviai cell strain RSC-364 induced with tumor necrosis factor （TNF）-α. Methods The AP-1 binding activity, JunB protein expression level and JunB mRNA level in RSC-364 cells were determined by gel shift assay, Western blot and RT-PCR respectively. Results TNF-α activated while CCK-8 inhibited the AP-1 in RSC-364 cells. Little JunB protein was expressed in unstimulated RSC-364 cells. The treatment with TNF-α for 2 h increased the expression level of JunB, which was promoted by CCK-8. FsK （a cAMP inducer） showed similar effect to that of CCK-8, which also increased the expression of JunB protein. However, CR1409 （CCK-A receptor）, CR2945 （CCK-B receptor agonist） and H89 （specific PKA inhibitor） partly blocked the effect of CCK-8. CCK-8 promoted the increased JunB mRNA expression in RSC-364 cells induced by TNF-α. Conclusion CCK-8 decreased the AP-1 binding activity and promoted the increased expression of JunB mRNA and protein induced by TNF-α, which was media- ted by CCK-A and CCK-B receptors, and cAMP/PKA pathway might be involved in the signal transduction.