Fig. 4: ΔMMAR_0267 enhances the survival of M. marinum within macrophages and inhibits cell apoptosis.

a THP-1 cells were infected with WT-Mm, ΔMMAR_0267, and ΔMMAR_0267::MMAR_0267 at a MOI of 10. Infected cells were lysed with 0.025% SDS at specified times. Error bars show standar d deviation; (*P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001; n = 5). b PMA-differentiated THP-1 macrophages were infected with the same strains at MOI of 10. Bacterial numbers were detected by plating lysates on MB 7H10 medium after 6, 24, 48, and 72 h of infection (n = 5). c and d CCK8 assay was used to assess THP-1 cell death when infected with M. marinum (n = 3). e Apoptosis levels in macrophages infected with the strains for 24 h were detected using a fluorescence microscope. f Inhibition of apoptosis by ΔMMAR_0267 was confirmed by Annexin V-FITC/PI double staining after 48 h exposure, with Q1-Q4 representing different cell states (n = 6).