Fig. 7: YspE2 promotes the survival of Y. pestis in macrophage and inhibits the inflammasome activation in an E3 ligase activity dependent manner.
From: Subversion of GBP-mediated host defense by E3 ligases acquired during Yersinia pestis evolution
The percentage of intracellular survival of Y. pestis 201 and ΔyspE2 in BMDMs isolated form C57BL/6 J (a, b) or Gbpchr3−/−, chr5−/− mice (d, e). BMDMs were directly infected with the Y. pestis 201 or ΔyspE2 (a, d), or primed with IFN-γ prior to infection (b, e). The living bacteria numbers inside the infected BMDMs were measured using a gentamycin protection assay. Triplicates samples were analyzed for each experiment and the averages with standard deviations were shown. Survival percentages of Y. pestis 201 and ΔyspE2 in the wild type BMDMs (c) and Gbpchr3−/−, chr5−/− BMDMs (f) at 2 and 4 hpi were shown, and comparisons between survival percentages of Y. pestis strains in the wild type BMDMs and Gbpchr3−/−, chr5−/− BMDMs were shown in g. Two-way ANOVA with Bonferroni’s multiple comparisons test was performed to analyze the significance of difference in the survival percentages. h U937 cells were infected with Y. pestis 201, ΔyspE2, ΔyspE2/YspE1, ΔyspE2/YspE2 or ΔyspE2/YspE2C386A strains as indicated, and both the culture medium and cell lysates were analyzed for IL-1β, IL-18 and caspase 1-p20. Inhibition of inflammasome activation in human macrophage-like U937 cells by Y. pestis requires YspE1/YspE2 E3 ligase activity. i RAW264.7 cells and BMDMs isolated from C57BL/6 J or Gbpchr3−/−, chr5−/− mice (j) were infected as described in h. k, l Represented the quantitative and statistical analysis results of h and P, respectively, from three independent experiments. Two-way ANOVA was performed to analyze the significance of difference in protein levels (*p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001).
