Emodin inhibiting neutrophil elastase-induced epithelial-mesenchymal transition through Notch1 signalling in alveolar epithelial cells.

The transition of alveolar type II epithelial cells into fibroblasts has been reported to cause and/or aggravate pulmonary fibrosis (PF), which is characterized by fibroblast proliferation, an enhanced production and accumulation of ECM (extracellular matrix), alveolar wall damage and functional capillary unit loss. Traditional Chinese medicine Emodin has been reported to inhibit TGF-ß-induced epithelial-mesenchymal transition (EMT) in alveolar epithelial cells through Notch signalling. In the present study, neutrophil elastase (NE, also known as ELA2) treatment promoted EMT, Notch1 cleavage (NICD/Notch1 ratio increase) and NICD nuclear translocation in RLE-6TN cells and A549 cells. The promotive roles of NE treatment in these events were significantly reversed by Notch1 knockdown. Traditional Chinese medicine Emodin treatment remarkably inhibited the enzyme activity of NE, suppressed EMT, Notch1 cleavage and NICD nuclear translocation within RLE-6TN and A549 cells, while NE treatment significantly reversed the effects of Emodin. Moreover, in RLE-6TN, the effects of NE on EMT, Notch1 cleavage and NICD nuclear translocation were remarkably attenuated by Emodin treatment and more attenuated by the combination of Emodin and neutrophil elastase inhibitor Sivelestat or notch signal pathway inhibitor DAPT. In conclusion, we revealed the involvement of NE-induced Notch1 cleavage in the functions of Emodin suppressing NE-caused EMT in RLE-6TN cells and A549 cells. This novel mechanism of Emodin inhibiting EMT might extend the application of Emodin in PF treatment.

[Effect of qidong huoxue decoction on inflammatory factors and TLR4 mRNA Expression in acute lung injury rats].

OBJECTIVE: To explore the effect of qidong huoxue decoction (QHD) on inflammatory factors and Toll-like receptor (TLR4) mRNA expressions in acute lung injury (ALI) rats. METHODS: Totally 50 healthy male SD rats were randomly divided into the blank control group, the lipopolysaccharide (LPS) model group, low, middle, high dose QHD groups according to body weight, 10 rats in each group. Rats in low, middle, high dose QHD groups were intragastrically administered with QHD at 4, 8, and 16 mL/kg 24, 12 h before modeling and 12 h after modeling, respectively. Normal saline was intragastrically administered to rats in the blank control group and the LPS model group. An ALI rat model was established using intratracheal instillation of LPS. Rats were killed after 24-h modeling. Then the bronchoalveolar lavage fluid was prepared. Contents of TNF-α, IL-1ß, and L-10 were detected using ELISA. TLR4 mRNA expressions were determined byreal time PCR. RESULTS: Compared with the blank control group, contents of TNF-α, IL-1ß , and IL-10 increased (P <0. 01), TLR4 mRNA expressions also increased in the LPS model group (all P <0. 01). Compared with the LPS model group, contents of TNF-α and IL-1ß decreased (P <0. 05, P <0. 01), IL-10 levels increased (P <0. 01) , TLR4 mRNA expressions were also reduced (P <0. 01), in high and middle dose QHD groups. Compared with the high dose QHD group, con- tents of TNF-α and IL-1ß increased in middle and low dose QHD groups (P <0. 05); IL-10 levels decreased (P <0. 05) in the low dose QHD group(P <0. 05), TLR4 mRNA expressions also increased in the low dose QHD group (P <0. 05). Compared with the middle dose QHD group, IL-10 levels was reduced, but TLR4 mRNA expressions increased in the low dose QHD group (P <0. 05). CONCLUSIONS: QHD had the protective effect on LPS induced ALI rats. Its mechanism might be associated with inhibiting TLR4 mRNA expressions, leading to decreased pro-inflammatory cytokines such as TNF-α and IL-ß, elevated anti-inflammatory cytokine IL-10, and thereby, correcting unbalanced inflammation.