Fig 2: Effect of cDC manipulation on Th1/Th2 cytokine production. (A) Levels of IFN-γ, (B) IL-1β, (C) IL-4 and (D) IL-10 were measured in the lungs by ELISA at 24 h post-LPS challenge, in order to evaluate the Th1/Th2 cytokine production. Data are presented as the mean ± standard deviation (n=6). *P<0.05 vs. Control; #P<0.05 vs. ARDS; &P<0.05 vs. FLT3L+ARDS; and $P<0.05 vs. lestaurtinib+ARDS. cDC, classical dendritic cell; Th, T helper cell; IFN, interferon; IL, interleukin; LPS, lipopolysaccharide; ARDS, acute respiratory distress syndrome; FLT3L, Fms-like tyrosine kinase 3-ligand.

Fig 3: Effect of FLT3 signaling on the aggregation and maturation of pulmonary cDCs. The aggregation and maturation of pulmonary cDCs were measured by flow cytometry at 6 h post-LPS challenge. (A) Representative dot plots and (B) quantification showing the percentage of cDCs (CD11c+CD11b+) among total lung cells in the experimental groups. (C) Representative histograms and (D) quantification showing the expression of MHC II in pulmonary cDCs in the experimental groups. (E) Representative histograms and (F) quantification showing the expression of CD80 in pulmonary cDCs in the experimental groups. Data are presented as the mean ± standard deviation (n=6). *P<0.05 vs. Control; #P<0.05 vs. ARDS; &P<0.05 vs. FLT3L+ARDS; and $P<0.05 vs. lestaurtinib+ARDS. FLT3, Fms-like tyrosine kinase 3; cDCs, classical dendritic cells; LPS, lipopolysaccharide; MHC II, major histocompatibility complex class II; ARDS, acute respiratory distress syndrome; FLT3L, Fms-like tyrosine kinase 3-ligand.

Fig 4: Effect of cDC manipulation on acute lung inflammation in ARDS. (A) Levels of TNF-α and (B) IL-6 were measured using ELISA to evaluate acute lung inflammation at 6 h post-LPS challenge. Data are presented as the mean ± standard deviation (n=6). *P<0.05 vs. Control; #P<0.05 vs. ARDS; &P<0.05 vs. FLT3L+ARDS; and $P<0.05 vs. lestaurtinib+ARDS. cDC, classical dendritic cell; ARDS, acute respiratory distress syndrome; TNF, tumor necrosis factor; IL, interleukin; LPS, lipopolysaccharide; FLT3L, Fms-like tyrosine kinase 3-ligand.

Fig 5: FLT3L expression in normal and ARDS lung tissues. FLT3L protein expression levels in normal and ARDS lung tissues were evaluated by western blotting at 6 h post-LPS challenge. Data are presented as the mean ± standard deviation (n=3). *P<0.05 vs. Control. FLT3L, Fms-like tyrosine kinase 3-ligand; ARDS, acute respiratory distress syndrome.