Fig. 7

MiR-155-5p inhibition alleviates iHvKp-exo or iHvKp-induced lung injury. A Mice were transfected with miR-155-5p inhibitor or control (NC) 24 h before tail vein injection of iHvKp-exo (n = 3). After 24 h, mice were euthanized, and lung tissue inflammation was assessed by HE staining. B Inflammatory cell recruitment was assessed by MPO activity assay. C Lung permeability was assessed by measuring BALF total protein concentration using a BCA assay. D Levels of pro-inflammatory cytokines were determined by RT-PCR. E Immunofluorescence intensity of macrophage polarization markers in lung tissue, represented by iNOS (green, M1) and Arg1 (red, M2). F Mice were transfected with miR-155-5p inhibitor or control (NC) 24 h before tail vein injection of iHvKp (n = 4). Upon reaching the humane endpoint or after 24 h, mice were euthanized, and lung tissue inflammation was assessed by HE staining. G Inflammatory cell recruitment was assessed by MPO activity assay. H Lung permeability was assessed by measuring BALF total protein concentration using a BCA assay. I Levels of pro-inflammatory cytokines were determined by RT-PCR. J Immunofluorescence intensity of macrophage polarization markers in lung tissue, represented by iNOS (green, M1) and Arg1 (red, M2). K Survival rate analysis of mice with or without miR-155-5p inhibition after iHvKp injection (n = 8), was performed using the log-rank test. (L) Mechanism of exosomal miR-155-5p promotes macrophage M1 polarization and inflammatory response in ALI induced by HvKp infection. Data are presented as mean ± SEM, *p < 0.05, **p < 0.01, ***p < 0.001