BackgroundNuclear factor-κB (NF-κB) is a central transcriptional factor and a pleiotropic regulator of many genes involved in acute lung injury. Andrographolide is found in the plant of Andrographis paniculata and widely used in Traditional Chinese Medicine, exhibiting potently anti-inflammatory property by inhibiting NF-κB activity. The purpose of our investigation was designed to reveal the effect of andrographolide on various aspects of LPS induced inflammation in vivo and in vitro.Methods and ResultsIn vivo, BALB/C mice were subjected to LPS injection with or without andrographolide treatments to induce ALI model. In vitro, MLE-12 cells were stimulated with LPS in the presence and absence of andrographolide. In vivo, pulmonary inflammation, pulmonary edema, ultrastructure changes of type II alveolar epithelial cells, MPO activity, total cells, neutrophils, macrophages, TNF-α, IL-6 and IL-1β in BALF, along with the expression of VCAM-1 and VEGF were dose-dependently attenuated by andrographolide. Meanwhile, in vitro, the expression of VCAM-1 and VEGF was also reduced by andrographolide. Moreover, our data showed that andrographolide significantly inhibited the ratios of phospho-IKKβ/total IKKβ, phospho-IκBα/total IκBα and phospho-NF-κB p65/total NF-κB p65, and NF-κB p65 DNA binding activities, both in vivo and in vitro.ConclusionsThese results indicate that andrographolide dose-dependently suppressed the severity of LPS-induced ALI, more likely by virtue of andrographolide-mediated NF-κB inhibition at the level of IKKβ activation. These results suggest andrographolide may be considered as an effective and safe drug for the potential treatment of ALI.

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Asthma is a common chronic pulmonary inflammatory disease, featured with mucus hyper-secretion in the airway. Recent studies found that glucagon like peptide-1 (GLP-1) analogs, including liraglutide and exenatide, possessed a potent anti-inflammatory property through a protein kinase A (PKA)-dependent signaling pathway. Therefore, the aim of current study was to investigate the value of GLP-1 analog therapy liraglutide in airway inflammation and mucus secretion in a murine model of ovalbumin (OVA)-induced asthma, and its underlying molecular mechanism. In our study, BALB/c mice were sensitized and challenged by OVA to induce chronic asthma. Pathological alterations, the number of cells and the content of inflammatory mediators in bronchoalveolar lavage fluid (BALF), and mucus secretion were observed and measured. In addition, the mRNA and protein expression of E-selectin and MUC5AC were analyzed by qPCR and Western blotting. Then, the phosphorylation of PKA and nuclear factor-κB (NF-κB) p65 were also measured by Western blotting. Further, NF-κB p65 DNA binding activity was detected by ELISA. OVA-induced airway inflammation, airway mucus hyper-secretion, the up-regulation of E-selectin and MUC5AC were remarkably inhibited by GLP-1 in mice (all p < 0.01). Then, we also found that OVA-reduced phosphorylation of PKA, and OVA-enhanced NF-κB p65 activation and NF-κB p65 DNA binding activity were markedly improved by GLP-1 (all p < 0.01). Furthermore, our data also figured out that these effects of GLP-1 were largely abrogated by the PKA inhibitor H-89 (all p < 0.01). Taken together, our results suggest that OVA-induced asthma were potently ameliorated by GLP-1 possibly through a PKA-dependent inactivation of NF-κB in mice, indicating that GLP-1 analogs may be considered an effective and safe drug for the potential treatment of asthma in the future.