Fig 2: Exosomal delivered miR-92a-3p modulates angiogenesis by targeting KLF2.A Venn diagram showing overlap of the data from miRanda, miRDB, TargetScan, PicTar, and PITA. B Potential targets of hsa-miR-92a-3p. C The mRNA level of KLF2 in the HUVECs transfected with synthetic mimic control (NC-m) or miR-92a-3p mimic (miR-92a-3p-m) (n = 4, *P < 0.05). D The mRNA level of KLF2 in the HUVECs treated with PBS or EXOs (n = 5, *P < 0.05). E Western blot analysis and relative quantification of protein expression indicating that exosome treatment or overexpression of miR-92a-3p could downregulate KLF2 expression in HUVECs (n ≥ 6, *P < 0.05). G The mRNA level of miR-92a-3p in the tumor tissues treated with PBS or exosomes (n = 6, *P < 0.05). H Representative blots of KLF2 in the tumor tissues treated with PBS or exosomes. I Quantitative evaluation of KLF2 protein expression in the tumor tissues treated with PBS or exosomes (n = 6, *P < 0.05).

Fig 3: Exosomes derived from WERI-Rb1 cells decrease the expression of KLF2 both in tumor tissues and vessels.A CD31 (red) and KLF2 (green) were labeled by immunofluorescence in tumors from the PBS‐injected or EXO‐injection groups. White arrowheads: KLF2 in the tumor tissue, orange arrows: KLF2 in the vessels, scale bar, 20 or 10 μm. B Quantification data showed KLF2(total)/DAPI area ratio, KLF2(tumor)/DAPI area ratio, and KLF2(vessel)/CD31 area ratio from the PBS‐injected and EXO‐injected groups (n = 5, *P < 0.05, **P < 0.01).

Fig 4: KLF2 levels in lung were decreased after hyperoxia. Simvastatin treatment significantly reversed KLF2 reduction after hyperoxia-induced lung injury. (a) KLF2 levels in lung tissues as determined by Western blotting. (b) Analyses of KLF2 levels based on Western blot results (normalized to β-actin levels). The values are the mean ± SD; n = 6, analyzed by two-way ANOVA with the Bonferroni post hoc test, ∗∗P < 0.01 versus the normoxia group; #P < 0.05 versus the hyperoxia group. (c) IF staining image of KLF2 in lung tissue (light microscopy, ×100). Scale bar represents 200 μm.

Fig 5: Hyperoxia and silencing of KLF2 significantly reduced KLF2 expression. (a) A549 cells were treated from 4 to 48 h, and cell viability was assessed using CCK8, n = 6, analyzed by one-way ANOVA followed by Tukey's post hoc test, ∗P < 0.05 and ∗∗∗∗P < 0.0001 versus the normoxia group. (b) Western blotting results of KLF2 in A549 cells. (c) Analyses of KLF2 expression (normalized to β-actin), n = 6, analyzed by two-way ANOVA with the Bonferroni post hoc test, ∗P < 0.05, ∗∗∗P < 0.001, and ∗∗∗∗P < 0.0001 versus the normoxia group; ###P < 0.001 versus the hyperoxia group. (d) IF staining images of KLF2 in each group (microscopy, ×400). Scale bars = 25 μm.