赖型钩端螺旋体溶血素HlyX对血管内皮细胞通透性的影响

Effect of hemolysin protein HlyX of Leptospira interrogans serovar Lai on permeability of vascular endothelial cells

目的:克隆表达赖型钩端螺旋体溶血素基因hlyX,观察其表达产物对人脐静脉内皮细胞(HU-VECs)通透性的影响,并初步探讨其机制。方法:将hlyX基因插入原核表达载体pET32a(+),构建重组质粒pET-hlyX,转化大肠杆菌BL21(DH3)以高效表达携带组氨酸标签的Trx-HlyX融合蛋白,并作亲和层析纯化。采用生物素标记白蛋白的酶联免疫吸附法测定目的蛋白对HUVECs单细胞层通透性的影响,并以流式细胞术及Ho-echst 33258荧光染色方法检测其作用于HUVECs后的细胞凋亡率。结果:成功构建了重组质粒pET-hlyX并高效表达出Trx-HlyX融合蛋白;与对照组相比较,蛋白Trx-HlyX作用于HUVECs后,明显增加其通透性(P<0.05),细胞凋亡率显著增加(P<0.05)。结论:重组质粒pET-hlyX高效表达出Trx-HlyX融合蛋白,纯化后的融合蛋白对HUVECs通透性有影响,且对HUVECs具有细胞毒性作用。

AIM： To clone and express the hemolysin gene hlyX of Leptospira interrogans serovar Lai and to investigate the effect of the expression product on the permeability of human umbilical vein endothelial cells（HUVECs）.METHODS： The recombinant plasmid pET-hlyX was constructed by inserting the hlyX gene into prokaryotic expression vector pET32a（＋）,and transformed into E.coli BL21（DH3） to express the fusion protein Trx-HlyX with a His-tag.The fusion protein was purified using HisTrap affinity columns.The permeability of the monolayer HUVECs was measured by enzyme-linked immunosorbent assay for biotin-labeled albumin.Flow cytometry and Hoechst 33258 staining were applied to measure the apoptotic rate of HUVECs after incubation with Trx-HlyX.RESULTS： The recombinant plasmid pET-HlyX was successfully constructed and the fusion protein Trx-HlyX was highly expressed.Compared with the control cells,the purified recombinant protein Trx-HlyX significantly increased the permeability of transfected cells and promoted apoptosis of HUVECs（P0.05）.CONCLUSION： The recombinant plasmid pET-hlyX highly expresses the fusion protein Trx-HlyX.Purified protein Trx-HlyX influences the permeability and has cytotoxicity on HUVECs.