ABSTRACT
Objective To investigate the role of recombinant Vibrio vulnificus cytolysin (rVvhA) in inducing THP-1 cells damage and study the pathway of associated calcium influx .Methods Inverted mi-croscope, CCK-8 cell proliferation kit, Fluo3/AM staining and caspase activity detection were performed to analyze the damage of THP-1 cells induced by rVvhA and the pathway of calcium influx .Results rVvhA had cytotoxic effects on THP-1 cells in a dose-dependent manner .The concentrations of extracellular K +and LDH were respectively up-regulated after 1 h and 6 h of 12 μg/ml rVvhA intervention .Verapamil , Mibe-fradil and SKF-96365 could not prevent the influx of free Ca 2+induced by rVvhA .The activities of caspase-3 and caspase-9 were singanificantly enhanced by rVvhA in a time-dependant manner .Conclusion rVvhA can induce THP-1 cells damage through triggering extracellular calcium influx via porous channel on cell membrane.Moreover, rVvhA might induce THP-1 cell apoptosis through activating caspase-9/3-dependent pathway .
ABSTRACT
Objective To investigate the cytolytic activity of extracellular cytolytic toxin rVVC of Vibrio vulnificus on the apoptosis of human ECV304 cells, and to analyze the activities of Caspase-3,-8 and -9. Methods The cytotoxic effect of refolded rVVC on the growth and apoptosis of ECV304 cells was identified by MTT, Hochest33342/PI fluorescent staining, flow cytometry and DNA agarose electrophoresis analysis, respectively. The activities of Caspase-3, -8 and -9 was measured using a colorimetric method. Results The viability of human ECV304 cells exposed to rVVC was inhibited by rVVC after 24 h. 2.0 HU/ml rVVC groups had a better cytotoxic effect to human ECV304 than that of 0.5 HU /ml rVVC groups. The apoptosis of human ECV304 cells in 2.0 HU/ml rVVC+40 μmol/L Z-VAD-FMK groups was relative reduced than that of 2.0 HU/ml of rVVC groups. After 0.5 h treatment with 2.0 HU/ml of rVVC, the Caspase-3 activity in human ECV304 cells increased gradually and reached the peak at 3 h (versus control groups, P<0.01). The activity of Caspase-8 and -9 remained unchanging. Conclusion The rVVC has cytotoxic effect on human ECV304 and the cytolysin is probably correlated with Caspase-3.