Figure 6. Effects of recombinant CXCL1 on host defense, emergency granulopoiesis, and NETosis in Nlrp6^−/− mice following Kp infection.

(A–G) Nlrp6^−/− mice were infected with Kp (10³ CFU/mouse) with or without administration of rCXCL1 or rIL-17A or BSA at 1 h post-infection. (A) Survival was monitored for 15 days. Statistical significance was determined by log-rank (n = 8 mice/group). (B–D) The bacterial burden was assessed in lungs, spleen, and BALF at 48 h post-infection. (E–G) Total numbers of white blood cells, neutrophils in BALF, and MPO activity in lung homogenates were measured. (n=4 mice/group). (H) Nlrp6^−/− BMDNs were seeded, pre-treated in the presence or absence of rCXCL1 (5nM) for an hour, infected, then SYTOX was added and incubated for 8 hours. Relative fluorescence intensity (RFU) was recorded to evaluate NETosis each hour up to 8 h post-infection. (H-L) Nlrp6^−/− mice were infected with Kp (10³ CFU/mouse) with or without administration of rCXCL1 or BSA at 1 h post-infection. Bone marrow was harvested at 48 h post infection. The FACs plot (I) and percentage of subpopulations #5 (J) and FACs plot (K) and percentage of GMPs (L) within the granulopoietic compartment are presented. (n = 4–6 mice/infection group, n = 3 mice/control group). In vitro experiments had at least four technical replicates. ANOVA (followed by Bonferroni’s post hoc comparisons) (B–G, I, K), and unpaired t-test (H). *, p<0.05; **, p<0.001; ***, p<0.001****, p<0.0001.