Figure 6.

Mtb FadD13 proteins induce the macrophage membrane broken. (a) Plate counting showing FadD13 promoted the survival of Mtb in macrophages. Differentiated THP‐1 macrophages were infected at a MOI of 10 with ΔfadD13 mutant and H37Rv for 1 and 24 hr, respectively. (b) FadD13 induced cell death of THP‐1 macrophage, indicating by release of LDH. Differentiated THP‐1 macrophages were stimulated with 10 μg/ml FadD13 purified proteins for 4 and 8 hr. The release of LDH (b) and cell viability (c) were detected. Blank: untreated THP‐1 macrophage; BSA: BSA treated THP‐1 macrophages; FadD13: FadD13 treated THP‐1 macrophages. (c) Decreased cell viability of THP‐1 macrophages treated with FadD13 proteins. (d) Membrane broken of macrophages treated with FadD13 proteins, staining with FM1‐43 fluorescent dye. The THP‐1 cells were treated as (b), then the cells were staining with 4 μM FM1‐43 and observed in 5 min using confocal microscope (Scale bar: 100 μm). (e) eEF1A1 had no influence on cell death of THP‐1 macrophage induced by FadD13, indicated by LDH release. THP‐1 macrophages transfected with eEF1A1 specific siRNA and control siRNA respectively, then stimulated with 10 μg/ml FadD13 purified proteins for 4 and 8 hr. The release of LDH in the culture medium was detected. Blank: normal THP‐1 macrophages; NC: THP‐1 macrophages transfected with control siRNA; siRNA eEF1A1: THP‐1 macrophages transfected with eEF1A1 specific siRNA. ^* p < .05 and ^** p < .01 (two‐tailed unpaired t test)