Figure 5.

sEV-CC16 inhibits bacterial-induced inflammation in lung epithelial cells

(A) Mice (n = 8 per group) received 1 μg of LPS (in 50 μL of PBS) via i.t. After 3 h, mice were given 7.5 × 10¹⁰ (in 50 μL of PBS) unlabeled or PKH26-labeled sEV-CC16. Mice were sacrificed 24 h after sEV-CC16 treatment. Immunofluorescence staining was performed in lung sections using an antibody against pan-CK (green, a marker of epithelial cell) to track the uptake of sEV-CC16. Scale bar, 100 μm. (B–F) NHBE and BEAS-2B cells were infected with K. pneumoniae (K. p) at an MOI of 1:5 ratio for 1 h. After washing, the cells were treated with 5 × 10⁸/mL PKH26-labeled sEV-Con or sEV-CC16. The internalization of sEVs into NHBE (B) and BEAS-2B (C) is observed with a fluorescence microscope. Scale bar, 100 μm. (D–F) 5 × 10⁸/mL sEV-Con, sEV-CC16 or 5 μg/mL rCC16 were added to K. pneumoniae (K. p)-infected BEAS-2B. mRNA levels of IL-1β (D), IL-6 (E), and IL-8 (F) were detected using qRT-PCR at 24 h after the sEV treatment. Results represent mean ± SD of three independent experiments and the data were analyzed by a one-way ANOVA followed by Tukey’s HSD. ns, p > 0.05; ∗∗p < 0.01.