Effects of cell cycles and their regulating genes on apoptosis of mononuclear-macrophages induced by Leptospira interrogans / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the effects of different cell cycles and their regulating genes on apoptosis of mononuclear-macrophages induced by Leptospira interrogans. Methods The diversity and alteration of cell cycles of murine mononuclear-macrophage line(J774A. 1 ) and human monocyte line(THP-1 ) before and after infected with L. interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai were detected using Cell Cycle Stain Kit plus flow cytometer. The cell cycle synchronized J774A. 1 and THP-1 cells were generated and then identified by using different cell cycle blocking agents and flow cytometer. By using Annexin V/PI Detection Kit combined with flow cytometer, the rates of early-apoptosis and late-apoptosis/necrosis in the synchronized and non-synchronized J774A. 1 and THP-1 cells after infection with L. interrogans strain Lai were determined. Several real-time fluorescence quantitative RT-PCRs were performed to the changes of mRNAs levels of p21, p27, p53, c-myc and cycA genes that associated with cell cycle and apoptosis in J774A. 1 and THP-1 cells before and after infected with L. interrogans strain Lai. Results There were G1, S and G2/M phases in both the non-infected normal J774A. 1 and THP-1 cells. On the contrast,the majority of infected J774A. 1 and THP-1 cells were stagnated at G1 phase, but the amount of S phase THP-1 cells was elevated while that of S phase J774A. 1 cells was not(P ＜0.05). No remarkable early-apoptosis in both the infected G1 phase J774A. 1 and THP-1 cells was found, whereas the rates of early-apoptosis and late-apoptosis/necrosis in the infected M phase J774A. 1 and THP-1 cells were significantly increased (P ＜0.05 ). Additionally, late-apoptosis / necrosis rate in the infected G1 phase THP-1 cells (P ＜ 0.05 )that not found in the infected G1 phase J774A. 1 cells. Compared to the non-infected cells, the p21 mRNA levels in the infected J774A. 1 and THP-1 cells were significantly elevated(P ＜0.05), and the c-myc and p27 mRNA levels in the infected J774A. 1 cells and the cycA mRNA level in the infected THP-1 cells were also higher than those in both the non-infected cells ( P ＜ 0.05 ). Conclusion Different cell cycles and their regulating genes have a role to affect the apoptosis of human and murine mononuclear-macrophages caused by L. interrogans with a diversity of cell line origins.