Fig. 6: Monocytes stimulate neutrophils MMP-9 expression by releasing CXCL2 and TNF-α.

A Representative flow cytometry images of skin infiltrated neutrophils in WT (BM WT), WT (BM Tnf^−/−), and Tnf^-−/− (BM WT) groups. 6 Tnf-deficient male mice were used as BM donors, all the recipient mice were female. B Statistical flow cytometry analysis of epidermal/dermal infiltrated neutrophil ratio (NTEM ratio) in WT (BM WT), WT (BM Tnf^−/−), Tnf^−/− (BM WT) group. n = 9, means ± SEM. C Quantification of gelatin zymography of invitro cultured neutrophils activated by TNF-α and CXCL2. n = 6, 3 male mice and 3 female mice were used to obtain BM and purify neutrophils in vitro, means ± SEM. D Images displaying gelatin zymography of (C). E Images display gelatin zymography of in vitro cultured neutrophils with dermal purified monocytes. F Quantification of gelatin zymography of in vitro cultured neutrophils with dermal purified monocytes in (E). n = 6, means ± SEM. G Quantification of gelatin zymography of in vitro cultured neutrophils with Tnf-competent-monocytes or Tnf-deficient-monocytes. I Images display gelatin zymography in (G). H Quantification of gelatin zymography of in vitro cultured neutrophils with siNC-monocytes or siCxcl2-monocyte. n = 6, means ± SEM. J Images display gelatin zymography in (H). The monocyte in (G, H) was collected from bone marrow and stimulated with LPS before coculture with neutrophils. The gelatin zymography in (D, E, I, J) are representative images of two or three independent trials. ND, not detected, ns, no significant difference. Data in (B) are from three independent trials; data in (C, F, G, H) are from two independent trials. Female mice were used to obtain BM in (E–J). Statistical analysis was performed using a two-tailed unpaired Student’s t-test in (F, G, H). Data in (B, C) were analyzed using a one-way ANOVA followed by Bonferroni’s post hoc test. Bonferroni-corrected p values are indicated in (B, C).