Inflammatory cell infiltration in experimental liver fibrosis is affected by inhibition of fibronectin matrix assembly

Prostaglandin E2 promotes Staphylococcus aureus infection via EP4 receptor in bovine endometrium

Prostaglandin E2 (PGE₂) enhances Staphylococcus aureus infection but its mechanism is not well understood. Here, we examined the effect of PGE₂ on Staphylococcal Protein A (SPA) expression in bovine endometrium and determined the role of select PGE₂ receptors (i.e., EP2 and EP4) in adhesion and internalization of S. aureus. S. aureus isolate SA113 was used for in vitro infection of bovine endometrial tissues and epithelial cells, with treatment conditions consisting of untreated control, SA113 treatment, SA113 + PGE₂, SA113 + PGE₂ + EP2 receptor antagonist (AH-6809), and SA113 + PGE₂ + EP4 receptor antagonist (AH-23848). Immunofluorescence assay revealed that PGE₂ could promote SPA expression in S. aureus-infected bovine endometrial tissues. PGE₂ also enhanced the adhesion and internalization of S. aureus in bovine endometrial cells. The addition of EP4 antagonist, but not the EP2 antagonist, abrogated the ability of PGE₂ to promote S. aureus SPA expression, adhesion, and internalization in endometrial cells. Our findings suggest that S. aureus infection in the endometrium is enhanced by PGE₂ through the EP4 receptor. This result is essential for the development of new approach to treating S. aureus infection, such as the application of EP4 antagonist as an adjunct drug treatment.

Growth and adherence of Staphylococcus aureus were enhanced through the PGE2 produced by the activated COX-2/PGE2 pathway of infected oral epithelial cells

Staphylococcus aureus is a major pathogen of varieties of oral mucous infection. Prostaglandin E2 (PGE₂) is a pro-inflammatory factor and Cyclooxygenase 2 (COX-2) is a critical enzyme of PGE₂ biosynthesis. The purpose of this study is to investigate whether Staphylococcus aureus can increase PGE₂ production of oral epithelial cells and how PGE₂ functions in the growth and adherence of Staphylococcus aureus. mRNA levels of COX-2, fnbpA and fnbpB were estimated by quantitative PCR. PGE₂ production was measured by Enzyme Linked Immunosorbent Assay (ELISA). The binding biomass of Staphylococcus aureus to human fibronectin was investigated by crystal violet staining and confocal laser scanning microscopy and the adherent force was measured by atomic force microscope (AFM). The COX-2 mRNA level and PGE₂ production were increased by Staphylococcus aureus. PGE₂ promoted the growth and biofilm formation of Staphylococcus aureus, enhanced the attachment of Staphylococcus aureus to the human fibronectin as well as to the HOK cells. The transcription of fnbpB was up-regulated by PGE₂ in both early and middle exponential phase but not fnbpA. These results suggest that the activation of COX-2/PGE₂ pathway in oral epithelial cell by Staphylococcus aureus can in turn facilitate the growth and the ability to adhere of the pathogen. These findings uncover a new function of PGE₂ and may lead to the potential of COX-2/PGE₂ targeting in the therapy of inflammation and cancer in both which the COX-2/PGE₂ pathway were observed activated.