Figure 6. Abrogation of ATP-induced IL-1β secretion in P. gingivalis-infected GEC by inhibition of P2X₄, P2X₇, or pannexin-1.

Primary GEC (C and D) and immortalized GEC (A and B) were infected with or without P. gingivalis (P.g.) at an M.O.I. of 100 for 6 hours, followed by treatment with different pharmaceutical agents. Infected cells were treated with 100 µM ATP, 3 mM ATP, 3 mM ADP, 3 mM AMP, or 3 mM UTP individually for 1 hour (A and C). Alternatively, infected cells were pre-treated with 50 µM 5-BDBD for 15 minutes, 100 µM PPADS for 15 minutes, 100 µM oxATP for 30 minutes, or 1 mM probenecid for 10 minutes, followed by treatment with 3 mM ATP for 1 hour (B and D). The supernatants were collected and subjected to ELISA to measure IL-1β secretion. (E) Primary GEC were transfected with siRNA sequences against P2X₄ or P2X₇ for one day, and mRNA levels were detected by qPCR. (F) Primary GEC depleted of P2X₄ or P2X₇ were infected with P. gingivalis (P.g.) and treated with probenecid and 3 mM ATP as shown in (B). IL-1β secretion in the supernatants was analyzed by ELISA. The values showed averages and SD from duplicate samples, which were obtained from three separate experiments.