Figure 5.
Stimulation with ATP activates caspase-1 in GECs. Primary GECs were infected with P. gingivalis at an MOI = 100 for 6 hrs (P.g.), treated with 2 μg/ml of E. coli LPS for 6 hrs, incubated with 5 mM ATP for 3 hrs, or incubated with 5 mM ATP for 3 hrs after 6 hrs of infection or LPS-treatment. Caspase-1 activation was measured by incubating treated or infected cells with a fluorescent caspase-1 substrate, as described in Experimental Procedures. LPS treatment or P. gingivalis infection have no effect on caspase-1 activity, but subsequent treatment with ATP induces a large increase in caspase-1 activation. The values show percent averages and S.D. from 3 samples of a representative experiment, and represent results obtained from at least three experiments. P = 0.02 for cells infected with P. gingivalis, compared with cells infected with P. gingivalis and then incubated with ATP.