Fig. 3

NF-κB and JNK play key roles in M. smegmatis-induced ER stress. RAW 264.7 cells were infected with M. smegmatis (MOI = 5) for the indicated times. a Total cell lysates were analyzed by western blot detecting p-IκBα. b RAW 264.7 cells were pretreated with BAY (10 μM) or CAPE (10 μM) for 1 h and infected with M. smegmatis. Phosphorylation of IκBα was analyzed by western blotting. c Western blot analysis was performed using specific antibodies against Bip, p-eIF2α, and CHOP. d MAPK (p-JNK, p-ERK, and p-p38) was analyzed by western blotting. e RAW 264.7 cells were pretreated with SP (20 μM), PD (50 μM), and SB (10 μM) for 1 h and infected with M. smegmatis. Western blot analysis was performed using specific antibodies against p-JNK, p-ERK, p-p38, f Bip, p-eIF2α, CHOP, and caspase-3. g RAW 264.7 cells were pretreated with SP (20 μM) or BAY (10 μM) and subsequently infected with M. smegmatis for 24 h. Apoptosis was assayed by Annexin-V/PI staining. h Inflammatory cytokine levels were determined by ELISA at the indicated time points. LPS (500 ng/mL, 24 h) was used as the positive control. Data are means ± SDs of three independent experiments. *p < 0.05, ***p < 0.001. M. smeg, Mycobacterium smegmatis; UN, uninfected; TM, tunicamycin; STS, staurosporine; LPS, lipopolysaccharide; SP, SP600125; PD, PD98059; SB, SB203580; BAY, Bay11–7082; CAPE, caffeic acid phenethyl ester