Effect And Mechanism Of Staphylococcus Aureus Lipoprotein On Neutrophil Prostaglandin E2 In Dairy Cows

Bacterial lipoprotein is an important component of the cell envelope of gram-positive bacteria.Loss of lipoprotein leads to the death of Gram-negative bacteria and the decrease of the vitality and pathogenicity of gram-positive bacteria.Pathogens can bind toll-like receptors and Nod-like receptors on the surface of host natural immune cells.Activate toll-like receptor and Nod-like receptor dependent natural immune system,promote the occurrence of host inflammatory response,mediate the innate first-line defense mechanism closely related to the adaptive immune system.Prostaglandin E2（PGE2）is one of many prostaglandin（PG）,which plays an important role in cell growth and regulation,and has immunosuppressive and anti-inflammatory effects.Staphylococcus aureus,as one of the main pathogenic bacteria caused by bacteria,is a hotspot of veterinary clinical research.Studies have found that staphylococcus aureus has a regulation effect on prostagranin E2 after acting on macrophages of dairy cows,but the regulation effect of STaphylococcus aureus on PGE₂after acting on neutrophils of dairy cows is unknown.Therefore,in this study,the effects of Staphylococcus aureus lipoprotein on the synthesis and secretion of neutrophil PGE₂in dairy cows were studied by using protein western blotting,enzyme-linked immunosorbent assay and real-time fluorescence quantitative polymerase chain reaction.By adding natural immune receptor inhibitors(TLR2 receptor blocker（C29）,TLR4 receptor blocker（TAK242）,NLRP3（MCC950）,cyclooxygenase-2 inhibitor（CAY10404）,and microsomal proges-E synthase-1 inhibitor（MF-63）,The regulation mechanism of PGE₂production by Staphylococcus aureus on neutrophils of dairy cows was studied.The results showed that compared with the staphylococcus aureus SA113 treated group,the secretion of PGE₂and the expression of COX-2 and MPGES-1 were significantly decreased after the staphylococcus aureus△LGT was knocked out.Compared with the staphylococcus aureus SA113 treated group,The secretion of neutrophil PGE₂,COX-2 and COX-2 in infected cows treated with TLR2 receptor blocker（C29）,TLR4 receptor blocker（TAK242）,NLRP3（MCC950）,cyciderase-2inhibitor（CAY10404）and progenin E2 synthase inhibitor（MF63）was significantly reduced The expression of MPGES-1 was significantly decreased.In conclusion,lipoprotein plays a key role in the secretion of PGE₂from neutrophil in cows infected with STaphylococcus aureus,and the natural immune receptors participate in and regulate the secretion of PGE₂after staphylococcus aureus acts on neutrophil in cows.