Proteomics Research Of BMECs Infected With Meningitic E.coli Strains

Extraintestinal pathogenic Escherichia coli is a kind of zoonotic Escherichia coli widely reported and concerned in recent years in academic and clinical fields.It can colonize a wide variety of host extraintestinal tissues and cause serious infections.Among them,bacterial meningitis caused by ExPEC has always been a huge challenge for human health as well as the development of livestock breeding.E.coli invasion of the blood-brain barrier,the essential step in the development of E.coli meningitis,requires specific signaling molecules.Previous studies have demonstrated that many bacterial components of ExPEC play important roles in bacterial invasion into host cells,penetration of the BBB,as well as survival of host immune clearance.Besides,previous studies have also reported some host proteins participating in ExPEC infection and invasion into BBB.However,the detailed molecular mechanisms involving in these processes remain unclear.Here,we employed an iTRAQ quantitative proteomics analysis coupled with LC-MS/MS to capture the differential protein expression profiles of BMECs upon infection with different E.coli strains,including porcine meningitis-causing E.coli strain PCN033,human meningitic E.coli RS218 and a non-meningitic E.coli strain HB101,and investigated the potential target proteins as well as the underlying mechanisms involving meningitic E.coli infection of BMECs.There were almost 3000 kinds of differentially expressed proteins being identified in this work.A total of 78 proteins were observed to be differentially expressed in PCN033-challenged cells,and 43 proteins were identified in RS218-infected cells.Only 6 proteins were observed to be affected by the challenge of non-meningitic strain HB101.Among these differentially expressed proteins,we found 12 proteins been commonly significantly changed in meningitic E.coli strain RS218 and PCN033 challenged groups,including TEL02,IFT74,CBWD6,TBPL1,RBM5,KRT9,HIST1H1C,HIST1H1D,HIST1H1B,HIST1H1E,MIF and DMD,which suggests that these proteins may be involved in the infection and invasion process of meningitis E.coli.Noticeably,we observed that MIF is the only one that been significantly upregulated in both meningitis E.coli infection groups,which promoted the production of cytokines and participated in the BBB disruption of BMECs in response to the infection.Via IPA analysis,we also found both NF-?B signaling and MAPK signaling pathways were involved in the meningitic E.coli infection process,by mediating the proinflammatory response upon the infection.Taken together,identification and characterization of these differential proteins and pathways lay an important foundation for further investigating the process as well as molecular mechanisms of meningitic E.coli invasion of host CNS.