Fig 1: Neutrophil depletion restores barrier integrity and restores basement membrane protein levels in MgK/platelet TSP1-deficient mice after injury.A Schematic illustrating the neutrophil depletion model in PA SN-induced lung injury (created in BioRender. Gheware, A. (2026) https://BioRender.com/q40u653.). WT and PF4CreThbs1flox KO (cKO) mice were i.v. injected twice with 200 µg of anti-Ly6G antibody or isotype antibody at -1 day and just prior to i.t. inoculation with PA SN. At 1 day post-inoculation, B BALF PMN cell counts, C BALF MPO and (D) BALF total protein content were measured. B–D n = 9 WT, n = 7 cKO mice per group. E Representative flow cytometry dot plots showing live CD45⁺CD11b⁺Ly6G⁺ neutrophils. Numbers indicate the percentage of gated cell population. F Quantification of lung neutrophils (CD45⁺CD11b+Ly6G⁺ cells) using flow cytometry. G BALF neutrophil elastase (NE) levels. F, G n = 4 WT, n = 4–5 cKO mice per group. H BALF IgM levels. n = 11 WT, n = 6 cKO mice in isotype control group and n = 5 WT, n = 6 cKO mice in anti-Ly6G group. I Representative flow cytometry dot plots display live CD45⁺CD41⁺ cells indicative of Mgk populations. Numbers represent percentage of gated cell population. J Mgk counts between groups quantified by flow cytometric analysis. n = 4 WT, n = 4–5 cKO mice per group. K BALF TSP1 levels. n = 18 WT, n = 14 cKO mice in isotype control group; n = 7 WT, n = 16 cKO mice in anti-Ly6G group. L BALF pro-COL1A1 levels, n = 4 WT, n = 4–5 cKO mice per group. M, N BALF COL4A1 levels and BALF COL6A1 levels. n = 11 WT, n = 6 cKO mice per isotype control group; n = 5 WT, n = 6 cKO mice per anti-Ly6G group. O Schematic illustrating Mgk/plt-derived TSP1 regulation of neutrophil function and matrix remodeling through stabilization of basement membrane COL6A1 in lung injury (created in BioRender. Lee, J. (2026) https://BioRender.com/e79xigt). *, p < 0.05; **; p < 0.01; ***, p < 0.001; ****, p < 0.0001. B, H Data analyzed by Kruskal-Wallis and uncorrected Dunn’s test and (C, D, F, G, J–N) two-tailed Welch’s ANOVA with unpaired t test with Welch’s correction for multiple comparisons. Each dot represents an individual mouse and bar graph represent the median. Each dot represents an individual mouse.