Fig 2: TGFβR2KO mice have improved lung morphometry in hyperoxia settings. (A) Representative images of lung histology (H&E stain) of NB TGFβR2KO mice exposed to RA or 100% O2 from PN1 – PN7 with appropriate controls. Scale bar: 100 μm (B) Bar graph showing morphometric analysis of mean chord length in hyperoxia exposed PN7 TGFβR2KO mice as compared to room air controls. (C) Bar graph showing morphometric analysis of septal thickness in hyperoxia exposed PN7 TGFβR2KO mice as compared to room air controls. (D) Representative images of immunohistochemistry of myeloperoxidase (MPO) staining showing of inflammatory cells (neutrophils) in the lungs NB TGFβR2KO mice exposed to RA or 100% O2 from PN1 – PN7 with appropriate controls. Scale bar: 100 μm (E) Bar graph showing MPO levels (measured by ELISA) in hyperoxia exposed PN7 TGFβR2KO mice as compared to room air controls. N = 4 in each group; *p < 0.05, ***p < 0.001.

Fig 3: Lack of Lcn2 expression causes higher infection burden 3 weeks after aerosol challenge with M.tb H37Rv. (A) Bacterial load per lung in mice with M.tb H37Rv shown as colony-forming units (CFU) (n = 13–16 per group). (B) MPO concentrations measured by ELISA in total lung homogenate (n = 7–8 per group). (C) Total number of Ly6G+, CD11b+ neutrophils isolated from lung measured by flow cytometry (n = 5–8 per group). Horizontal bars indicate mean. The dotted line indicates mean for uninfected controls. ***p < 0.001, ****p < 0.0001 by student's T-test or two-way ANOVA with Sidaks's multiple comparison test.

Fig 4: FOXN3 phosphorylation by p38 positively regulates lung inflammation and injury. (A) H&E histological staining of lung sections from WT or Foxn3 KI mice infected with MRSA or the vehicle PBS. (B) Anti-CD68 immunohistochemical staining of lung sections from WT or Foxn3 KI mice infected with MRSA or the vehicle PBS. Scale bars, 100 μm. (C) Quantitative PCR analysis of pro-inflammatory factor expression in the lungs of WT or Foxn3 KI mice infected with MRSA or the vehicle PBS (n = 4 for the WT and WT + S. aureus groups, n = 3 for the Foxn3KI/KI and Foxn3KI/KI + S. aureus groups). (D) BCA analysis of total protein concentrations in BAL fluid from WT or Foxn3 KI mice infected with MRSA or the vehicle PBS (n = 4 for the WT and WT + S. aureus groups, n = 3 for the Foxn3KI/KI and Foxn3KI/KI + S. aureus groups). (E) Neutrophil enzyme MPO measurement in BAL fluid from WT or Foxn3 KI mice infected with MRSA or the vehicle PBS (n = 4 for the WT and WT + S. aureus groups, n = 3 for the Foxn3KI/KI and Foxn3KI/KI + S. aureus groups). (F) WBC counts in BAL fluid from WT or Foxn3 KI mice infected with MRSA or the vehicle PBS (n = 4 for the WT and WT + S. aureus groups, n = 3 for the Foxn3KI/KI and Foxn3KI/KI + S. aureus groups). (G and H) ELISA of IL-1β (G) or IL-6 (H) in BAL fluid from WT or Foxn3 KI mice infected with MRSA or the vehicle PBS (n = 4 for the WT and WT + S. aureus groups, n = 3 for the Foxn3KI/KI and Foxn3KI/KI + S. aureus groups). The data C-H were assessed by one-way ANOVA and are shown as the mean ± SD. N.S, not significant; *P <0.05, **P <0.01 and ***P <0.001 for comparisons between the indicated groups.

Fig 5: FOXN3 disruption induces pulmonary inflammation and injury. (A) Quantitative PCR analysis of FOXN3 RNA levels in lungs of WT or FOXN3-KO mice (n = 4). (B) Immunoblot analysis of the FOXN3 protein levels in lungs of WT or FOXN3-KO mice. (C) H&E histological staining of lung sections from WT or FOXN3-KO mice infected with MRSA or a vehicle (PBS) control. (D) Anti-CD68 immunohistochemical staining of lung sections from WT or FOXN3-KO mice infected with MRSA or a vehicle (PBS) control. Scale bars, 100 μm. (E) Quantitative PCR analysis of pro-inflammatory factor expression in lungs of WT or FOXN3-KO mice infected with MRSA or a vehicle (PBS) control (n = 4). (F) BCA analysis of total protein concentrations in BAL fluid from WT or FOXN3-KO mice infected with MRSA or a vehicle (PBS) control (n = 4). (G) Neutrophil enzyme MPO measurement in BAL fluid from WT or FOXN3-KO mice infected with MRSA or a vehicle (PBS) control (n = 4). (H) WBC counts in BAL fluid from WT or FOXN3-KO mice infected with MRSA or a vehicle control (n = 4). (I and J) ELISA of IL-1β (I) or IL-6 (J) in BAL fluid from WT or FOXN3-KO mice infected with MRSA or a vehicle (PBS) control (n = 4). The data A was assessed by Student's t-test and the data E-J were assessed by one-way ANOVA. All data are shown as the mean ± SD. *P <0.05, **P <0.01 and ***P <0.001 for comparisons between the indicated groups.