Solidago decurrens Lour. controls LPS-induced acute lung injury by reducing inflammatory responses and modulating the TLR4/NF-κB/NLRP3 signaling pathway

Abstract

Ethnopharmacological relevance

Acute lung injury (ALI) is a lethal respiratory disease associated with severe inflammatory responses. Solidago decurrens Lour. (SdL) has been shown to exhibit anti-inflammatory and antibacterial activities. However, the pharmacological effects of SdL on ALI and the underlying mechanisms remain unexplored.

Aim of the study

In this study, we investigated the ability of SdL to control lipopolysaccharide (LPS)-induced inflammation in vitro and in vivo. We took an integrated approach of using network pharmacology with molecular and cellular techniques to understand the molecular mechanisms for SdL's anti-inflammatory activity.

Methods

UHPLC-QE-Orbitrap-MS was employed to identify bioactive compounds in SdL. Using network pharmacology approaches, we investigated SdL's potential targets and pathways against ALI. The active components and potential targets of SdL were obtained from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, and target genes of ALI were obtained from Online Mendelian Inheritance in Man (OMIM), GeneCards, Therapeutic Target Database (TTD), DisGeNET database. The common target genes were collected using Venny. The SdL-compounds-common targets-ALI network was constructed using Cytoscape 3.9.1. The protein-protein interaction (PPI) network of SdL-ALI targets was established, with core targets identified and visualized through Cytoscape 3.9.1. The DAVID database was used for GO and KEGG enrichment analysis. Subsequently, we used the MTT assay, qPCR technique, ELISA, and immunoblotting to determine cell viability, gene expression, cytokines, and specific protein modulators, respectively. We used H&E staining to detect pathological changes in the lung tissues.

Results

A total of 19 compounds in SdL were screened through the UHPLC-QE-Orbitrap-MS and TCMSP databases, and a total of 209 potential gene targets were obtained from these 19 compounds. ALI obtained a total of 1,932 gene targets from OMIM, GeneCards, TTD, DisGeNET database. A total of 140 common gene targets of SdL and ALI were obtained through Venn diagrams. The results of the SdL-compounds-common targets-ALI network indicate that quercetin and kaempferol may be the main compounds for SdL in the treatment of ALI. The PPI results indicated that TNF, IL6 and IL1B played important roles in the regulation of ALI by SdL. The results of GO and KEGG enrichment analysis indicated TNF, Toll-like receptors and NF-kappa B pathways, suggesting the mechanism by which SdL controls ALI through its anti-inflammatory function. Subsequently, our results indicated that SdL treatments reduced COX-2 and iNOS, as well as suppressed the LPS-induced inflammatory cytokines (IL-1β and IL-6) in RAW 264.7 macrophage and lung tissues of mice. SdL treatment was able to suppress the LPS-induced NLRP3 inflammasome activation and the TLR4/NF-κB signaling pathway. Pretreatment of animals with SdL alleviated the LPS-induced pathological changes in the lung tissues.

Conclusion

Considering these results together, we suggested that SdL was capable of mitigating inflammation and LPS-induced ALI by modulating the TLR4/NF-κB/NLRP3 pathway. SdL should be seriously considered in clinical studies to control ALI.