Staphylococcus aureus lipoproteins play crucial roles in inducing inflammatory responses and bacterial internalization into bovine mammary epithelial cells

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

The internalization of S. aureus 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 S. aureus in bMECs. This research aimed to evaluate the mechanism by which Lut reduces S. aureus-induced inflammation in bMECs. Through GO and KEGG enrichment analysis, researchers analyzed the differentially expressed genes in bMECs infected with S. aureus 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 S. aureus 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 S. aureus through the TLR2, NF-κB, and MAPK signaling pathways. This process might account for the anti-inflammatory properties of Lut.

Staphylococcus aureus lipoproteins in infectious diseases

Infections with the Gram-positive bacterial pathogen Staphylococcus aureus remain a major challenge for the healthcare system and demand new treatment options. The increasing antibiotic resistance of S. aureus poses additional challenges, consequently inflicting a huge strain in the society due to enormous healthcare costs. S. aureus expresses multiple molecules, including bacterial lipoproteins (Lpps), which play a role not only in immune response but also in disease pathogenesis. S. aureus Lpps, the predominant ligands of TLR2, are important for bacterial survival as they maintain the metabolic activity of the bacteria. Moreover, Lpps possess many diverse properties that are of vital importance for the bacteria. They also contribute to host cell invasion but so far their role in different staphylococcal infections has not been fully defined. In this review, we summarize the current knowledge about S. aureus Lpps and their distinct roles in various infectious disease animal models, such as septic arthritis, sepsis, and skin and soft tissue infections. The molecular and cellular response of the host to S. aureus Lpp exposure is also a primary focus.