髓核细胞中活化T细胞核因子对ADAMTS-4启动子的调控作用

Role of nuclear factor of activated T-cells in regulating ADAMTS-4 promoter activity in nucleus pulposus cells

目的观察活化T细胞核因子(NFAT)-1、4、5在髓核细胞中对聚蛋白聚糖酶ADAMTS-4启动子活性的影响,初步探讨椎间盘退变可能的分子机制。方法将ADAMTS-4-pβ-gal-Basic质粒经限制性内切酶XhoⅠ及HindⅢ酶切后插入到PGL3-Basic质粒中,经筛选后获得纯化的PGL3-ADAMTS-4质粒。离体培养后,使用Lipofectamine 2000系统进行转染实验,将NFAT-1、NFAT-4、NFAT-5以及DN-TonEBP质粒和PGL3-ADAMTS-4质粒共转染大鼠髓核细胞。将正常髓核细胞和转染后的髓核细胞分别作为对照组和实验组。用双荧光素酶报告基因检测系统测髓核细胞中NFAT-1、NFAT-4、NFAT-5对ADAMTS-4基因启动子活性的影响。结果构建了ADAMTS-4基因双荧光素酶报告质粒,发现2个NFAT结合元件。与对照组相比,转染NFAT-1的髓核细胞中ADAMTS-4启动活性被抑制(P<0.05),而转染NFAT-4、NAFT-5以及DN-TonEBP的髓核中ADAMTS-4启动子活性改变无统计学意义(P>0.05)。结论 NFAT-1可调控ADAMTS-4的表达,可能在椎间盘生理以及退变过程中对蛋白聚糖的含量起重要调控作用,为椎间盘退变的生物学治疗提供了一个新的策略。

Objective To observe the regulatory effect of nuclear factor of activated T-cells （NFAT）-1, 4, 5 on ADAMTS-4 promoter activity in nucleus pulposus cells, so as to discuss the underlying molecular mechanism of intervertebral disc degeneration. Methods The ADAMTS-4-pβ-gal-Basic was inserted into PGL3-Basic vector after double digestion by the restriction enzyme Xho Ⅰ and HindⅢ. The purified PGL3-ADAMTS-4 plasmid was obtained through screening. Rat nucleus pulposus cells were cultured in vitro and, via Lipofectamine2000 transfection reagent, transfected with NFAT-1, NFAT-4, NFAT-5 or DN-TonEBP expressing plasmids with or without appropriate backbone vector and 175 ng ADAMTS-4 promoter. The normal cells were taken as controls and transfected cells were taken as treatment group. Dual-LuciferaseTM reporter assay system was used to detect the effect of NFAT-1, 4, 5（TonEBP） on ADAMTS-4 promoter activity. Results We successfully constructed PGL3-ADAMTS-4 plasmid and identified two NFAT-Bind elements in the promoter. Compared with the control group, ADAMTS-4 promoter activity was significantly inhibited in NFAT-1 group （P 〈 0. 05）. While the activities of ADAMTS-4 promoter in NFAT-4, NAFT-5 and DN-TonEBP groups showed no significant changes（P〉0.05）. Conclusion NFAT-1 can regulate ADAMTS-4 expression, which may play a role in modulating aggrecan content in the intervertebral disc physiology and/or intervertebral disc degeneration, providing a new strategy for biological treatment of intervertebral disc degeneration.