Zhang Jihong, Pan Cuiyun, Xu Tiantian, Niu Zhipeng, Ma Chengkai, Xu Cunshuan
College of Life Science, Henan Normal University, Xinxiang 453007, China; Key Laboratory for Cell Differentiation Regulation, Xinxiang 453007, China.
College of Life Science, Henan Normal University, Xinxiang 453007, China; Key Laboratory for Cell Differentiation Regulation, Xinxiang 453007, China.
Gene. 2015 May 25;563(1):45-51. doi: 10.1016/j.gene.2015.03.010. Epub 2015 Mar 6.
Interleukin 18 (IL-18) is a pleiotropic cytokine and capable of stimulating proliferation of certain cell types. Nonetheless, its effect on normal liver cells cultured remains unclear. In the present study, we discovered that IL-18 expression level was remarkably elevated at 3.3 and 8.6h after synchronized BRL-3A rat liver cells (G0 phase) re-entering the cell cycle. In addition, recombinant rat IL-18 (rrIL-18) at dosages 5-10 ng/ml increased the cell viability compared to untreated cells (with medium only) at 24 and 48 h (P<0.05). At the same time, the percentage of BrdU-labeling cells was also significantly increased (P<0.01). On the other hand, knockdown of IL-18 expression with short interference RNA (siRNA), the cell viability began to decline at 24h and significantly decreased compared to negative control (NC) at 48 and 72 h after transfection (P<0.05). Meanwhile, the number of cells in division phase (G2/M) was reduced in parallel. Further, after treatment with rrIL-18 (5 ng/ml), IL-18 and its receptor subunit IL-18Rα increased both at mRNA and protein levels. Moreover, the expression levels of adaptor molecule MyD88, transcription factor NF-κB and its downstream targets cyclin B1 and cyclin B2 were remarkably enhanced in BRL-3A cells stimulated by rrIL-18. Furthermore, transcription factor ATF2 and its targeted genes cyclin A2, Bcl-2 were also markedly increased after treatment with rrIL-18. These results demonstrated that IL-18 can augment cell proliferation via NF-κB and p38/ATF2 pathway by targeting cyclin B1, cyclin B2, cyclin A2 and Bcl-2 in BRL-3A rat liver cells.
白细胞介素18（IL-18）是一种多效性细胞因子，能够刺激某些细胞类型的增殖。然而，其对培养的正常肝细胞的影响仍不清楚。在本研究中，我们发现同步化的BRL-3A大鼠肝细胞（G0期）重新进入细胞周期后3.3小时和8.6小时，IL-18表达水平显著升高。此外，与未处理细胞（仅加培养基）相比，剂量为5-10 ng/ml的重组大鼠IL-18（rrIL-18）在24小时和48小时时可提高细胞活力（P<0.05）。同时，BrdU标记细胞的百分比也显著增加（P<0.01）。另一方面，用小干扰RNA（siRNA）敲低IL-18表达后，转染后24小时细胞活力开始下降，48小时和72小时时与阴性对照（NC）相比显著降低（P<0.05）。同时，分裂期（G2/M）细胞数量也相应减少。此外，用rrIL-18（5 ng/ml）处理后，IL-18及其受体亚基IL-18Rα在mRNA和蛋白水平均增加。而且，接头分子MyD88、转录因子NF-κB及其下游靶点细胞周期蛋白B1和细胞周期蛋白B2的表达水平在rrIL-18刺激的BRL-3A细胞中显著增强。此外，转录因子ATF2及其靶向基因细胞周期蛋白A2、Bcl-2在用rrIL-18处理后也显著增加。这些结果表明，IL-18可通过靶向BRL-3A大鼠肝细胞中的细胞周期蛋白B1、细胞周期蛋白B2、细胞周期蛋白A2和Bcl-2，经由NF-κB和p38/ATF2途径增强细胞增殖。
