Luteolin Alleviates Inflammation Induced by Staphylococcus aureus in Bovine Mammary Epithelial Cells by Attenuating NF-κB and MAPK Activation

The internalization of <i>S. aureus</i> in bMECs is a major pathogenic mechanism leading to mastitis, causing significant economic losses in the dairy industry. Numerous plants contain Lut, a natural flavonoid with anti-inflammatory and antioxidant properties. However, little is known about Lut's ability to reduce inflammation caused by <i>S. aureus</i> in bMECs. This research aimed to evaluate the mechanism by which Lut reduces <i>S. aureus</i>-induced inflammation in bMECs. Through GO and KEGG enrichment analysis, researchers analyzed the differentially expressed genes in bMECs infected with <i>S. aureus</i> in NCBI GEO (GSE139612) and also analyzed the targets of Lut predicted by various online platforms. These studies identified two overlapping signaling pathways, the NF-κB and the MAPK pathways. We stimulated bMECs with <i>S. aureus</i> for two hours and then added Lut for ten hours, with a total duration of twelve hours. The expression levels of TLR2-MyD88-TRAF6 components, inflammatory cytokines, and protein phosphorylation associated with the MAPK and NF-κB signaling pathways were then assessed. Based on all of the results, Lut inhibited the generation of inflammatory cytokines in bMECs that were induced by <i>S. aureus</i> through the TLR2, NF-κB, and MAPK signaling pathways. This process might account for the anti-inflammatory properties of Lut.