Tryptanthrin Down-Regulates Oncostatin M by Targeting GM-CSF-Mediated PI3K-AKT-NF-κB Axis

Background: Oncostatin M (OSM) is involved in several inflammatory responses. Tryptanthrin (TRYP), as a natural alkaloid, is a bioactive compound derived from indigo plants. Objectives/ Methods: The purpose of this study is to investigate the potential inhibitory activity of TRYP on OSM release from neutrophils using neutrophils-like differentiated (d)HL-60 cells and neutrophils from mouse bone marrow. Results: The results showed that TRYP reduced the production and mRNA expression levels of OSM in the granulocyte–macrophage colony-stimulating factor (GM-CSF)-stimulated neutrophils-like dHL-60 cells. In addition, TRYP decreased the OSM production levels in the GM-CSF-stimulated neutrophils from mouse bone marrow. TRYP inhibited the phosphorylation of phosphatidylinositol 3-kinase (PI3K), AKT, and nuclear factor (NF)-κB in the GM-CSF-stimulated neutrophils-like dHL-60 cells. Conclusions: Therefore, these results reveal for the first time that TRYP inhibits OSM release via the down-regulation of PI3K-AKT-NF-κB axis from neutrophils, presenting its potential as a therapeutic agent for inflammatory responses.