Andrographolide Suppresses Expressions of Coagulation and Fibrinolytic Inhibition-Related Factors in LPS-Induced Alveolar Epithelial Cell Type II via NF-κB Signal Pathway In Vitro

BACKGROUND: Andrographolide (Andro) has been confirmed to ameliorate alveolar hypercoagulation and fibrinolysis inhibition via NF-κB pathway in acute respiratory distress syndrome (ARDS), but the specific target of Andro is unknown. PURPOSE: Our aim is to explore the specific target of Andro through which the drug exerted its effects on alveolar hypercoagulation and fibrinolytic inhibition in LPS-induced ARDS. METHODS: AECII was treated with different doses of Andro for 1 h, and then stimulated with LPS for 24 h. Expressions of tissue factor (TF), plasminogen activator inhibitor (PAI)-1 and tissue factor pathway inhibitor (TFPI) were detected. Concentrations of thrombin-antithrombin complex (TAT), pro-collagen type III peptide (PIIIP), antithrombin III (ATIII) and activated protein C (APC) in cell supernatant were measured by enzyme linked immunosorbent assay (ELISA). NF-κB signaling pathways activation was simultaneously determined. AECII with p65 down-/over-expression were used as control. RESULTS: Andro effectively inhibited TF and PAI-1 and promoted TFPI expressions on AECII induced by LPS stimulation. Andro also significantly suppressed the productions of TAT and PIIIP but promoted ATIII and APC secretions from the LPS-treated cell. Furthermore, Andro application obviously inhibited NF-κB signaling pathway activation provoked by LPS, as shown by decreased level of phosphorylation (p‑)-IKKβ/IKKβ, p-p65/p65 and p65 DNA binding activity. The effects of Andro on those factors were obviously strengthened by down- but were weakened by up-regulation of p65 gene in AECII cell. CONCLUSIONS: Our data demonstrates that targeting AECII is the mechanism by which Andro ameliorates alveolar hypercoagulaiton and fibrinolytic inhibition via NF-κB pathway in ARDS. Andro is worth to be clinically further studied in ARDS treatment.