Fig. 6

miR-30d-5p inhibition alleviates TNF-Exo or CLP-induced lung injury. Mice were injected with TNF-Exo (300 μg/mouse) intraperitoneally (a–f) or subjected to sham or CLP (g–l) for 24 h. The miR-30d-5p inhibitor or negative control (NC) was transferred into each mouse 1 day before TNF-Exo injection or CLP surgery. Relative expression levels of miR-30d-5p (a, g), inflammatory cytokine mRNA (IL-6, IL-1β, TNF-α) and iNOS mRNA (b, h), NLRP3 and caspase-1 mRNA expression (c, i) in the lung tissues were measured by RT-qPCR. d, j Representative images of direct immunofluorescence staining of DNA (blue), CD68 (red) and TUNEL (green) in the lung sections. Scale bar, 50 μm. e, k Representative images of direct immunofluorescence staining of DNA (blue), CD68 (red) and iNOS (green) in the lung sections, and white arrows indicate iNOS positive macrophages. Scale bar, 50 μm. f, l Evaluation of lung histology by H&E staining (magnification × 400). Green arrows indicate neutrophils in the alveolar and interstitial space, red arrows indicate alveolar macrophages, yellow arrows indicate hyaline membranes, blue arrows indicate proteinaceous debris filling the airspaces, and black arrows indicate thickening of the alveolar walls. Lung injury scores were assessed. Scale bar, 50 μm. Student’s t test or one-way analysis of variance with Tukey's multiple comparisons test was used for the analysis. m Survival rate of CLP mice with or without miR-30d-5p inhibition (n = 8) and log-rank test was used for the analysis. n Schematic representation of the mechanism by which neutrophil-derived exosomes induce M1 macrophage polarization and prime macrophage pyroptosis in sepsis-related ALI. Graphs represent means ± SEM, n ≥ 3; *P < 0.05, **P < 0.01 compared within two groups (h, i ^*,**P compared with Sham + NC group, ^#,##P compared with CLP + NC group)