GRA7-I-induced inflammasome activation was required for antimicrobial activity in MTB-infected macrophages.
(A and B) BMDMs from PKCα+/+ and PKCα-/- mice (A) and BMDMs were transduced with lentivirus-shRNA-NS or lentivirus-shRNA-ASC for 2 days (B) infected with MTB (MOI = 1) for 4 h and then stimulated with rGRA7 (1, 5, 10 μg/ml) and its mutants for 18 h. IB analysis for IL-1β p17, IL-18 p18, or caspase-1 p10 in supernatants (SN), ASC, NLRP3, pro-IL-1β, pro-IL-18, or pro-caspase-1 in whole-cell lysates (WCL). Actin was used as a loading control. (C and D) Intracellular survival of MTB was assessed by CFU assay. BMDMs were infected with MTB for 4 h, followed by treatment with rGRA7, and then lysed to determine intracellular bacterial loads. The data are representative of five independent experiments with similar results (A and B). Data shown are the mean ± SD of five experiments (C and D). Significant differences (*P < 0.05; **P < 0.01; ***P < 0.001) compared with rVector. CFU, colony-forming units. ns, not significant.