Immunospecific Responses to Bacterial Elongation Factor Tu during Burkholderia Infection and Immunization

Burkholderia pseudomallei is the etiological agent of melioidosis, a disease endemic in parts of Southeast Asia and Northern Australia. Currently there is no licensed vaccine against infection with this biological threat agent. In this study, we employed an immunoproteomic approach and identified bacterial Elongation factor-Tu (EF-Tu) as a potential vaccine antigen. EF-Tu is membrane-associated, secreted in outer membrane vesicles (OMVs), and immunogenic during Burkholderia infection in the murine model of melioidosis. Active immunization with EF-Tu induced antigen-specific antibody and cell-mediated immune responses in mice. Mucosal immunization with EF-Tu also reduced lung bacterial loads in mice challenged with aerosolized B. thailandensis. Our data support the utility of EF-Tu as a novel vaccine immunogen against bacterial infection

Designing the MIRRI information system

Culture collections (CCs) manage fundamental data about preserved microorganisms. To enable the exploitation of these resources requires standardized, and simplified, access to the associated information. To this end, a European Microbial Resource Research Infrastructure, MIRRI, was established. A prime objective of MIRRI is to unite and provide universal access to the information available in European public collections of microorganisms through a dynamic Information System, the MIRRI-IS. In this context, the desired outcome would include a repository for microbial domain Biological Resource Centre (mBRC) catalogues in a common format, the validation of catalogue contents to provide quality data, the interconnection of domain information systems for data extension, a unique portal for catalogues and associated data and an interoperable system based on Application Programming Interfaces (APIs) and service based interfaces and workflows. The architectural design of the system foresees the adoption of a standard format for exchanging data between CCs, a Minimum Data Set for essential data, to evolve into Minimum Information about Biological Resources (MIaBRe), a user-friendly interface, as well as APIs and services/workflows for integration software. Three systems were developed in the MIRRI preparatory phase. They have been developed to cope with distinct issues. The BacDive demonstrator aims at extending the contents of catalogues with a greater number of better defined data. The StrainInfo demonstrator is targeted towards a better integration among collection catalogues through the identification of common strains. It makes some order in strains available in various collections and makes possible the re-organization of collections and the sharing of data between catalogues. The USMI Galaxy demonstrator is aimed at supporting data curation and at integrating catalogues with external resources. It makes it possible to integrate collections' data with other bioinformatics databases by leveraging on existing tools and with little development requirements. Moreover, it allows the improvement of a collection’s data by automating links to external databases. A five-year plan for the implementation of the MIRRI-IS has been defined. The four main lines included in the plan are data curation, interoperability, applications development and IT competence. Data curation is meant to be developed by the progressive adoption of Standard Operating Procedures, able to lead user catalogues from the current Minimum Data Set to a structured extended data set and finally to data sets fully compliant with Minimum Information about Biological Resources (MIaBRE) guidelines, still under definition. Interoperability will lead current separated catalogues to interact with an integrated repository of reference data which will finally allow user access to all catalogues through a common portal.</jats:p

Expression of Beta-Defensin 131 Promotes an Innate Immune Response in Human Prostate Epithelial Cells

Previously, using the Illumina HumanHT-12 microarray we found that β-defensin 131 (DEFB131), an antimicrobial peptide, is upregulated in the human prostate epithelial cell line RWPE-1 upon stimulation with lipoteichoic acid (LTA; a gram-positive bacterial component), than that in the untreated RWPE-1 cells. In the current study, we aimed to investigate the role of DEFB131 in RWPE-1 cells during bacterial infection. We examined the intracellular signaling pathways and nuclear responses in RWPE-1 cells that contribute to DEFB131 gene induction upon stimulation with LTA. Chromatin immunoprecipitation was performed to determine whether NF-κB directly binds to the DEFB131 promoter after LTA stimulation in RWPE-1 cells. We found that DEFB131 expression was induced by LTA stimulation through TLR2 and p38MAPK/NF-κB activation, which was evident in the phosphorylation of both p38MAPK and IκBα. We also found that SB203580 and Bay11-7082, inhibitors of p38MAPK and NF-κB, respectively, suppressed LTA-induced DEFB131 expression. The chromatin immunoprecipitation assay showed that NF-κB directly binds to the DEFB131 promoter, suggesting that NF-κB is a direct regulator, and is necessary for LTA-induced DEFB131 expression in RWPE-1 cells. Interestingly, with DEFB131 overexpression in RWPE-1 cells, the accumulation of mRNA and protein secretion of cytokines (IL-1α, IL-1β, IL-6, and IL-12α) and chemokines (CCL20, CCL22, and CXCL8) were significantly enhanced. In addition, DEFB131-transfected RWPE-1 cells markedly induced chemotactic activity in THP-1 monocytes. We concluded that DEFB131 induces cytokine and chemokine upregulation through the TLR2/NF-κB signaling pathway in RWPE-1 cells during bacterial infection and promotes an innate immune response