HIV-1 gp120蛋白对人血-视网膜屏障细胞的毒性作用

目的 探索HIV-1 gp120蛋白侵犯人血.视网膜屏障的机制.方法 原代培养人血-视网膜屏障细胞(HBRBC),包括人视网膜微血管内皮细胞(HRCEC)、人视网膜微血管周细胞(HRCPC)、人视网膜色素上皮细胞(HRPE),以培养基作为对照.用MTT法观察7种不同浓度(0.01～0.15 mg/L)的HIV-1 gp120蛋白作用24 h和0.08 mg/L HIV-1 gp120蛋白作用不同时间(4～72 h)对3种细胞的生长抑制作用.0.08、0.1、0.12、0.15 mg/L的HIV-1 gp120蛋白作用24 h后,用流式细胞仪检测其对3种细胞凋亡率和线粒体膜电位(△ψm)的影响;用Western免疫印迹检测Cleaved cagpase-9蛋白的活化情况.用透射电镜观察经0.08 mg/L HIV-1 gp120蛋白处理24 h前后3种细胞超微结构的变化.结果 HIV-1gp120蛋白作用24 h,低浓度(<0.08mg/L)对3种细胞的活性均没有明显影响,而当浓度超过0.08mg/L时,对细胞的增殖活性有明显的抑制作用,呈浓度依赖性(HRCEC:r=-0.763,P<0.01;HRCPC:r=-0.804,P<0.01;HRPE:r=-0.698,P<0.01).HIV-1 gp120蛋白(0.08mg/L)作用12 h即可显著抑制细胞的增殖活性.24、48和72 h抑制效应更明显,相对增殖率分别为HRCEC:84%、70%、41%、22%,HRCPC:80%、69%、38%、18%,HRPE:86%、73%、45%、26%,抑制效应呈时间依赖性(HRCEC:r=0.833.P<0.01;HRCPC:r=-0.784,P<0.01;HRPE:r=-0.701,P<0.01).HIV-1 gp120蛋白作用24 h后与对照组相比,各浓度组3种细胞凋亡率增加、△ψm明显降低以及Cleaved cagpase-9蛋白表达增强,均呈浓度依赖性.透射电镜示0.08mg/LHIV-1 gp120蛋白处理24h后,3种细胞均出现了线粒体肿胀、溶酶体增多等早期凋亡的微观改变.结论 HIV-1 gp120蛋白能够抑制人血-视网膜屏障细胞的增殖并具有诱导凋亡的作用,破坏线粒体的结构和功能是其可能的机制.

Cytotoxity of HIV-1 gp120 protein on human blood-retinal barrier ceils

Objective To study the mechanism of human blood-retina barrier (BRB) destroyed by HIV- 1 gp120 protein. Methods Human blood-retina barrier cells (HBRBCs) including human retina capillary endothelial cells (HRCECs), human retina capillary perieytes (HRCPCs), human retinal pigment epithelium (HRPE) were primarily cultured. Culture media were regarded as eontrol. MTT method was used to observe the inhibition effect of HIV-1 gp120 protein on eell viability at 7 different concentrations (0.01 to 0.15 mg/L) for 24 h, and at a fixed concentration(0.08 mg/L) for different times (4-72 h). After 0.08, 0.1, 0.12 and 0.15 mg/L HIV- 1 gp120 protein were applied in those cells for 24 h, cell apoptotie rates and membrane potential of mitochondria (△ψm) were measured by flow eytometry. Activation of Cleaved caspase-9 was detected by Western blot. Change of cell mierostructure with 0.08mg/L HIV-1 gp120 protein before and after 24 h was detected by transmission electron microscopy (TEM). Results Concentration of HIV-1 gp120 protein less than 0.08 mg/L did not influence cell viability at 24 h. But at the concentration of more than 0.08 mg/L, HIV-1 gp120 protein could obviously inhibit HBRBCs proliferation with a concentration-dependent manner(HRCECs: r=-0.763, P<0.01 ; HRCPCs: r=-0.804, P<0.01 ; HRPE: r=-0.698, P<0.01). HIV-1 gp120 protein(0.08 mg/L) significantly inhibited cells proliferation at 12 h, and this inhibition effect was more stronger at 24,48,72 h with a time-dependent increase (HRCECs: r=-0.833, P<0.01 ; HRCPCs: r=-0.784, P<0.01 ; HRPE: r=-0.701, P<0.01). The relative growth rates were HRCECs: 84%, 70%, 41%, 22% ; HRCPCs: 80%, 69%, 38%, 18% ; HRPE: 86%, 73%, 45%, 26% respectively. Compared with control group, the ratio of apoptotic cells of HBRBCs and expression level of Cleaved caspase-9 protein increased but △ψm decreased at different concentrations with HIV-1 gp120 protein treatment for 24 h. The changes of these indexes were all concentration-dependent manner. Early apoptotic changes of HBRBCs such as mitochondrial swelling and lysosome increase were observed by TEM after treatment of 0.08 mg/L HIV- 1 gp120 protein for 24 h. Conclusion HIV-1 gp120 protein can inhibit proliferation and induce apoptosis of HBRBCs. The mechanism is probably associted with the structure and function destruction of mitochondiral.