Functions And Pro-Inflammatory Mechnasiam Study Of Streptococcus Suis Serotype 2 Protein HP1330

Streptococcus suis 2 is an important zoonotic pathogens that individual suffering from swine streptococcosis often shows the symptoms of meningitis arthritis and endocarditis.In recent years,China broke out two large-scale outbreaks of streptococcus suis infection,causing dozens of deaths and hundreds of infections,which become a severe threat to industry and people’s property security.Since the first human cases of swine streptococcus founding in the 1970s,streptococcus suis has infected nearly 1600 people worldwide.Studies show that streptococcus suis in the early stages of infection will colonize in the almond in host,which causes a strong inflammatory reaction,and up regulate the inflammatory cytokines like IL-1 MCP-1,IFN β and TNFα etc.An important release of proinflammatory mediators is thought to take place during S.suis systemic infections,which is regarded as one of the reasons that results in the quick deaths of host in early infection.Currently accepted view is that streptococcus suis adheres the membrane of epithelial cells to evade the host immune recognition,but its really mechanism to break through the innate immune barrier of host remains unclear.Our study focus on a proinflammatory protein screened by our laboratory in early studies named HP1330,one of matrix metalloproteinases depending on metal ions to hydrolyse cell matrix.We hope that through the study we can provide some information of inflammatory disorders caused by streptococcus suis after infecting the host,and also theoretical basis for prevention and control of the diseases.The main research content of our study is as follows:(1)A significant up regμLating function for IL-1,MCP-1,TNFα and IFNβ by HP 1330 screened in early stage of our laboratory were found in RAW264.7.We verify the pro-inflammatory activity of HP1330 by RT-PCR and Elisa.(2)HP 1330 upregulates the cytokines TNFα、MCP-1、IL-1 mainly through ERK,NF-kB,and P38 signal pathways by the inhibitor experiment.(3)Through the TLR receptor inhibition experiment we found HP 1330 play the proinflammatory activity is mainly achieved by TLR4.(4)We built mutant △1330 to get a further determination of proinflammatory activity by HP1330.HP1330 have a significant function of promotion inflammation verified by the model of RAW264.7 and BALB/c.(5)However,we found a significant difference of chain length between △1330 and SC 19 by gram stain.So,we detect the difference of their chain length by gram stain at different OD values.Combing the analysis of BLAST and the result of enzyme activity detection,we found tha HP1330,as a kind of matrix metalloproteinase,can react with the main compounds of cell walls called PGN.So we speculate that with the deficiency of HP1330,some compounds can’t be hydrolyze efficiently,leading to the longer chain length and easier elimination by the host.Combining with the results above,we speculated that peptidoglycan may be the substrate of HP1330.