Activity of mitogen-activated protein kinases in the esophageal epithelium of patients with Barrett's esophagus

Mechanisms of Luteolin Against Gastro-Esophageal Reflux Disease Based on Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Luteolin is a naturally occurring flavonoid. The effectiveness of luteolin-rich drugs in treating gastro-esophageal reflux disease (GERD) through traditional Chinese medicine has been demonstrated. This study aimed to identify the potential targets and mechanisms of action of luteolin for the treatment of GERD. An innovative approach combining network pharmacology and molecular dynamics was used to explore the potential therapeutic mechanisms of luteolin and to facilitate the further development of GERD treatment. Drug and disease target information was screened from public databases to obtain 159 intersecting targets through the construction of Venn diagrams. Subsequently, a protein‒protein interaction (PPI) network was constructed, and 10 core targets were identified. Through Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, relevant biological processes, cellular components, and molecular functions related to the treatment of GERD were identified and revealed. KEGG pathway analyses showed enrichment of signaling pathways, including the TNF, IL-17, NF-kappa B, and Toll-like receptor pathways. The molecular docking results indicated that luteolin can effectively bind to 10 core targets. Finally, molecular dynamics simulations confirmed the formation of stable protein‒ligand complexes when IL6 binds to luteolin. In conclusion, network pharmacology, molecular docking, and molecular dynamics simulations were utilized to investigate the mechanism by which luteolin treats GERD. These findings establish a theoretical foundation for future research on the efficacy of luteolin in treating GERD.

Inhibition of p38 MAPK activation attenuates esophageal mucosal damage in a chronic model of reflux esophagitis

BACKGROUND

Reflux esophagitis (RE) is one of the common gastrointestinal diseases that are increasingly recognized as a significant health problem. This study was designed to investigate the role of p38 mitogen-activated protein kinase (MAPK) in experimental chronic RE model of rats.

METHODS

Chronic acid RE rats were induced by fundus ligation and partial obstruction of the pylorus and treated with SB203580 (a p38 MAPK inhibitor, i.p., 1 mg/kg/day) for 14 days.

KEY RESULTS

Immunohistochemical staining and Western blotting results revealed the activation of p38 MAPK signaling in the esophagus mucosa 14 days post injury. Through gross and histological assessment, we found that inhibition of p38 MAPK activation by SB203580 attenuated esophageal mucosal damage in RE rats. Inhibition of p38 MAPK activation in RE rats attenuated esophageal barrier dysfunction, through enhancing the expression of tight junction proteins and reducing the expression of matrix matalloproteinases-3 and -9. Inhibition of p38 MAPK activation in RE rats reduced CD68-positive cells in esophagus mucosa and mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β in esophagus and protein levels of TNF-α, IL-6, and IL-1β in serum. In addition, we found that inhibition of p38 MAPK activation in RE rats suppressed protein expression of inducible nitric oxide synthase and reduced formation of nitric oxide (NO), 3-nitrotyrosin, and malondialdehyde in esophagus.

CONCLUSIONS & INFERENCES

Inhibition of p38 MAPK activation attenuated esophageal mucosal damage in acid RE rats, possibly by modulating esophageal barrier function and regulating inflammatory cell recruitment, and the subsequent formation of cytokines, NO, and reactive oxygen species.