TCMs has accumulated valuable information alleviating lung diseases. WYJ, from steamed roots of Curcuma wenyujin, was included in the 2020 edition of the Pharmacopoeia of People s Republic of China. Modern pharmacological studies have demonstrated that the ingredients or extracts from WYJ have antibacterial, antitumor anti-inflammatory and antioxidant[26] effects. There are studies reported that curcumin, an essential ingredient of WYJ, have anti-pulmonary fibrosis in murine model[27, 28]. Hui’s study showed potential anti-fibrotic effects of WYJ in liver fibrosis[29]. In our present study, we investigated the effect of WYJ against PF and the related molecular mechanism.
In this study, we established PF mice model by administering (via the trachea) bleomycin at a dose of 5 mg/kg. This model could cause a pulmonary pathological change similar to that of patients with lung fibrosis[30, 31]. We explored the effect of WYJ on PF from the perspectives of the survival rate, HYP, and histopathological examination. In our study, three dosage groups of WYJ were evaluated. The results showed that all dosage groups hindered lung fibrosis, and the WYJ-H and WYJ-M groups demonstrated the best therapeutic effect.
We identified 23 major compounds from WYJ using UHPLC-LTQ-Orbitrap. Further the network pharmacology results revealed that 128 targets could be potential targets on the treatment of PF, and PPI network showed 48 of them were key targets. KEGG analysis results and the compound–target-pathway network suggested that STAT3, SRC, IL6, MAPK1, AKT1, EGFR, MAPK8, MAPK14 and IL1B are important targets. MAPK8, MAPK1, AKT1, MAPK14, EGFR and IL1B were the important targets in MAPK signaling pathway. STAT3 was the top node in the compound–target-pathway network and involved in multiple pathways. The prediction results indicated that WYJ relieved pulmonary fibrosis mainly through inhibiting the MAPK signaling pathway and down-regulating the expression of p-STAT3.
MAPKs signaling cascades participate in the regulation of processes including cell cycle progression, cell migration, cell survival and differentiation[32, 33]. Katerina M and colleagues[34] found BRAF,a major signaling intermediate protein that regulates the MAPK/ERK pathway༌increased in lung tissue of patients with IPF compared with normal. Another study found activated MAPKs are significantly increased in lung parenchyma of patients with IPF compared that of normal[35]. Bach1 ameliorated fibrosis and inflammation via blocking MAPK pathway in pulmonary fibrosis in recent study[36]. Another study proved that the blockade of ERK by PD98059 attenuated the increase of collagen mRNA expression induced by TGF-β1[37]. In our study, the WYJ treatment remarkably reduced the increased α-SMA, Collagen-1, and levels of p-MAPK1 in BLM-induced PF model and TGF-β1 induced HPF cells. The inhibitory effect of WYJ on PF may function mainly through modulating the MAPK signaling pathway.
Compound–target-pathway network revealed that STAT3 is the top node in PF treatment with WYJ. STAT3 regulates cell growth, proliferation, differentiation, and migration.[38] Important fibrotic factors including TGF-β1, PDGF, FGF-2, and IL-13 can activate STAT3[39–43] and further lead to pulmonary fibrosis. Levels of phosphorylated STAT3 have been shown to be elevated in patients with IPF and bleomycin model[44–47]. C-188-9[42], a synthetic small molecule inhibitor of STAT3 phosphorylation, inhibited STAT3 activation and decreased the development of pulmonary fibrosis in BLM-induced PF model. Accordingly, targeting common downstream mediators of fibrogenic mediators, STAT3, PF can be treated by several of the cellular pathways. In our study, elevated levels of p-STAT3 were observed in BLM-induced PF model and TGF-β1 induced HPF cells. The WYJ treatment remarkably reduced the increased p-STAT3. WYJ relieves pulmonary fibrosis by down-regulating the expression of P-STAT3.
We also explored the effect of WYJ on PF from another perspective using molecular docking. The results proved that compounds of WYJ have good binding activity with key targets (MAPK8, MAPK1, AKT1, MAPK14, EGFR, IL1B and STAT3), further illustrating that WYJ could hinder lung fibrosis via inhibiting the MAPK signaling pathway and down-regulating the expression of p-STAT3.
This study has some drawbacks. Compounds which have the most effective therapeutic effects require further definite and research. The network pharmacology had limitations. A total of 23 Compounds of WYJ were confirmed based on UHPLC-LTQ-Orbitrap. However, only targets of 15 Compounds were obtained from databases and the network pharmacology only involved targets of 13 Compounds. Whether the remaining Compounds play an anti-pulmonary fibrosis effect needs further research. The pharmacological mechanism by which WYJ treated PF need further exploration.