幽门螺杆菌cagⅡ对胃上皮细胞IL-8基因转录的影响机制

The effect and mechanisms of the cag Ⅱ of Helicobacter pylori on the transcription of IL-8 in gastric epithelial cells

[目的]探讨Hp cagⅡ对胃上皮细胞IL-8基因转录的影响及信号传导机制。[方法]构建cagⅡ基因位点缺失Hp突变以及带有IL-8报告基因的人胃癌细胞系L5F11，用液体闪烁计数仪测定荧光素酶(IL-8转录)活性．川ELISA法测定IL-8蛋白浓度。[结果]所有HP突变株诱导荧光素酶活性与IL-8蛋白浓度较亲代菌株26695均降低(0.13±0.01vs 0.59±0.05×10^4epm．P<0.01;0.73=0.13vg 2.22±0.65ng/ml．P<0.05)。PTK抑制berbimycin A不仅抑制Hp诱导的荧光素酶活性（0.71±0.18vs1.51=0.23×10^6epm，P<0.05)．而且抑制IL-8蛋白表达(0．83±0.41vs3.22±0.59ng/ml，P<0.05)，但berbimycinA对TNFa诱导的荧光素酶活性及IL-8蛋白表达均无影响(P均＞0.05)；PKA抑制剂H7抑制NTFa诱导的荧光素酶活性(0．74±0.16vs2.62±0.26×10^6epm．P<0.01)及IL-8蛋白表达(1．45±0.38vs4.12±0．43ng/ml，P<0.01)．而对Hp诱导的荧光素酶活性无影响(P>0.05)。[结论]Hp cag Ⅱ中的多个基因能够调节胃上皮细胞IL-8基因转录，且这一作用主要经蛋白酯氨酸激酶途径。

To study the effect of the cag Ⅱ of H. pylofi on the transcription of IL-8 and to explore the mechanisms of signal transduetion in the transcription of IL-8 induced by H. pylofi in gastric epithelial cells. Methods The constructed L5F11 cells were eocultured with different isogenic mutants of H. pylori and the transcription and translation of lL-8 were indicated by the luciferase activity and IL-8 rotein respectively. Results-The ability to induce the luciferase and IL-8 protein by the mutant strains were much lower than that of by parent strain 26695 (0.13±0.01vs 0.59±0.05×10~6 cpm, P<0.01;0.73±0.13 vs 2.22±0.65 ng/ml,P<O.05;respectively). Exposure of LSFll ceils to herbimycin A reduced both H. pylofi-induced luciferase activity(0.71±0.18 vs 1.51±0.23 x 10~6 cpm, P<0.05)and IL-Sprotein production (0.83±0.41 vs 3.22±0.59 ng/ml, P<0.05) but in had no effect on TNFα-induced IL8 transcription (P>0.05) and IL-8 protein production ( P>0.05 ). H7 inhibited TNFα-induced luciferase (0.74±0.16 vs 2.62±0.26×10~6 cpm, P<0.001)and IL-8 protein production (1.45±0.38 vs 4.12±0.43 ng/ml,P<0.01) but had no significant effect on H. pylori-induced luciferase activity (P>0.05). Conclufions-This results showed that multiple genes in the tag Ⅱ locus play an important role in transcription of IL-8 in L5F11 gastric epithelial cells and transcription IL-8 gene induced by H. pylori is mainly mediated by the protein tyrosine kinase.