Mycobacterium abscessus infection leads to enhanced production of type 1 interferon and NLRP3 inflammasome activation in murine macrophages via mitochondrial oxidative stress
Fig 5
mtROS led to enhanced intracellular survival of MAB-R strains via IFN-I-dependent cell-to-cell spreading and enhanced cell cytotoxicity.
(A) J774A.1 cells pre-treated with mito-TEMPO (100 μM) and infected with rEGFP_Mma-R or rEGFP_Msm (M. smegmatis) at an M.O.I. of 10 for different times (2, 6 and 24 h). The percentage of EGFP-positive cells was measured by flow cytometry (FACSCalibur). (B) J774A.1 cells were pre-treated with mito-TEMPO and infected with strains of MAB-R, MAB-S or M. smegmatis (Msm) at an M.O.I. of 10 for 24 h. Infected cell lysates were serially diluted and plated onto 7H10 agar plates for CFU assays. (C) Cytotoxicity was quantitated by measuring lactate dehydrogenase (LDH) in the infected cell supernatants. Error bars represent the SD. Statistical significance was determined by two-tailed Student’s t-test (A-C).