Objective To explore the role of sulforaphane (SFN) on the regulation of airway mucin 5AC mucin expression in the airway epithelial cell line (A549), and the underlying mechanism. Methods The experiments were performed in culture of PMA and H2O2 induced A549 in vitro. A549 cells divided into three groups: the control group, the model group (PMA and H2O2) and the intervention groups (SFN+PMA; SFN+H2O2). The intervention group's cells were pretreated with SFN for 30 mins before exposure to stimuli (PMA or H2O2). The MUC5AC, Nrf2 and the antioxidant gene HO-1, NQO1, GCLC mRNA levels were analyzed by real time-PCR, and protein production was assayed by western blot. Results Compared with the control group, expression of MUC5AC mucin was increased after being stimulated by PMA or H2O2 (P<0.05), but it was significantly inhibited by SFN (P<0.05). SFN induced the expression of Nrf2 gene and the antioxidant gene HO-1 (compared with the control and model groups,P<0.05). Conclusion Sulforaphane involves the airway mucous hypersecretion induced by PMA and H2O2, and Nrf2/HO-1 signaling pathway may play an important role in mucin MUC5AC regulation.
ObjectiveTo investigate effects of high expression of miR-499a-5p on lung injury in rats with acute respiratory distress syndrome (ARDS) by targeting matrix metallopeptidase-16 (MMP-16).MethodsThe experiment set up sham operation group, model group, miR-499a-5p mimic group, MMP-16 group, miR-499a-5p mimic+MMP-16 group, D-ribofuranosylbenzimidazole (DRB, Nrf2 signaling pathway inhibitor) group, miR-499a-5p mimic+DRB group. A rat model of ARDS was constructed by cecal puncture. One hour before surgery, the transfection complex (50 μL) was injected into the trachea with a micro-syringe. DRB (5 mg/kg) was intraperitoneally injected 30 min before surgery. The expression levels of miR-499a-5p and MMP-16 in lung tissue were detected by RT-qPCR; Alveolar type Ⅱ epithelial cells of model group rats were separated and MMP-16 3 'UTR WT and MUT luciferase report plasmid were transfected into alveolar type Ⅱ epithelial cells with miR-499 respectively to verify the targeting relationship between miR-499 and MMP-16; the targeted relationship was verified by the dual luciferase reporter gene; lung injury was observed by hematoxylin-eosin staining; The level of inflammatory factors in bronchoalveolar lavage fluid (BALF) and the level of oxidative stress in lung tissue were detected by enzyme-linked immunosorbent assay; The expression levels of NAD(P)H: quinone oxidoreductase 1 (NQO1), heme oxygenase (HO)-1, and nuclear factor-erythroid 2-related factor 2 (Nrf2) proteins in lung tissues were analyzed by Western blotting.ResultsmiR-499a-5p was down-regulated in the lungs of ARDS model rats (P<0.01), while MMP-16 was highly expressed (P<0.01); miR-499a-5p and MMP-16 3'UTR regions had binding sites, and miR-499a-5p directly targeted negative regulation of MMP-16 expression (P<0.01); overexpression of miR-499a-5p significantly reduced the right lung wet-to-dry weight ratio in the ARDS rats (P<0.05), reduced lung tissue damage (P<0.01), and reduced tumor necrosis factor α, interleukin (IL)-1β and IL-6 levels in BALF (P<0.01), decreased malondialdehyde and myeloperoxidase levels in lung tissue, increased total anti-oxidant capacity (P<0.01), and up-regulated NQO1, HO-1, Nrf2 protein expression in lung tissue (P<0.01). However, this phenomenon was significantly reversed after the addition of MMP-16 and DRB.ConclusionOverexpression of miR-499a-5p attenuates lung injury in rats with ARDS by targeting negative regulation of MMP-16 via activating the Nrf2 signaling pathway.