白念珠菌分泌的天冬氨酸蛋白酶6诱导人单核细胞凋亡

Apoptosis of human monocytes induced by secretory aspartic proteinase 6 secreted by Candida albicans

目的检测白念珠菌分泌的天冬氨酸蛋白酶6(Sap6)对人类单核细胞系(THP-1细胞)增殖的影响,明确Sap6蛋白是否具有诱导单核细胞凋亡的活性。方法用XTT比色法检测25、50μg/ml Sap6对THP-1细胞增殖率的影响;在流式细胞仪下用Annexin V-FITC/PI细胞凋亡试剂盒检测25、50μg/ml Sap6诱导THP-1细胞凋亡情况;用Con A-FITC/DAPI双染法在荧光显微镜下观察Sap6作用于THP-1细胞的位置。结果与25μg/ml比较,50μg/ml Sap6蛋白显著抑制人THP-1细胞增殖率(P=0.0001),并提高THP-1细胞早期凋亡率(P=0.0001);Sap6蛋白进入THP-1细胞内,结合于细胞核。结论白念珠菌分泌的Sap6在体外能够进入人单核细胞内,诱导凋亡,从而抑制细胞增殖率。

Objective To investigate the effects of secretory aspartic proteinase 6 （Sap6） from Candida albicans on human monocyte cell line （ THP-1 ） proliferation, and to find out whether Sap6 has an activity to induce the apoptosis of monocytes. Methods The effect of Sap6 on THP-1 cell proliferation was evaluated by XTF assay. Apoptotic rate of THP-1 cells induced by Sap6 was meas- ured by flow cytometry with Annexin V-FITC/PI apoptosis detection kit. The location of Sap6 on THP-1 ceils was examined by ConA- FITC/DAP1 staining under fluorescence microscope. Results 50 μg/ml of Sap6 had a significantly inhibitory effect on the proliferative rate of THP-1 （ P = 0. 0001 ）. 50 μg/ml of Sap6 increased the early apoptotic rate of THP-1 （ P = O. 0001 ）. Sap6 was internalized into THP-1 and combined with nucleus of the cells. Conclusion Secretory aspartic proteinase 6 from Candida albicans could access into human monocytes in vitro, and inhibit the proliferation of monocytes by inducing cell apoptosis.