Study On The Mechanism Of Plasminogen In Listeria Monocytogenes Meningitis

Background and purpose:Plasminogen and its activation product,plasmin,play an important role in fibrinolysis and degradation of extracellular matrix,cell migration,tissue remodeling,wound healing,and pro-inflammatory.Studies have reported that many pathogens can support the plasminogen system through plasminogen activators to promote the subsequent activation of proteases,break down extracellular proteins,and disrupt the complement system to escape the host’s immune response.The surface proteins enolase、DnaK(heat shock factor)、and EF-TU(elongation factor TU)of Listeria monocytogenes can also bind to plasminogen,but the specific role is unknown.The purpose of this study:1.To explore the role of plasminogen in Listeria monocytogenes meningitis and provide new research ideas for the pathogenesis of bacterial meningitis;2.Identify the action system involved in the use of the host plasminogen system by bacteria to provide a better experimental basis for further research in the future.Methods:Animal models of Listeria meningitis were established by injecting bacteria into the tail vein and conducting cell pathological experiments in vivo.The experimental group and control group experiments were used to determine the role of plasminogen system in Listeria meningitis.In vitro experiments,cerebrovascular endothelial cells were used to establish an in vitro blood-brain barrier model,that is,the change of adhesion and invasion of bacterial endothelial endothelial cells in different groups was calculated by setting up experimental groups and control groups.Data analysis:Statistics was analyzed by Graphpad Prism software,and the Mean±SEM of each group was calculated.According to different analysis methods,Unpair t test or One-way ANOVA or two-way ANOVA were used for analysis;when P-value<0.05,the difference Statistical significance.Result:1.Listeria monocytogenes can use plasminogen to increase its adhesion and invasion and enhance its pathogenic effect.Compared with the control group,the difference was statistically significant.2.The above beneficial effects can be suppressed by aminocaproic acid,and the inhibitory effect is positively correlated with the concentration of aminocaproic acid.3.Through in vitro mouse experiments,it was found that the mice in different treatment groups had no statistically significant load on the blood,liver and spleen at the same time.Compared with the control group,the difference between the bacterial load and survival rate in the brain of the experimental group was statistically significantConclusion:Listeria monocytogenes can use the host’s plasminogen system to increase its own pathogenicity.