title: An in vivo high-throughput screening approach targeting the type IV secretion system component VirB8 identified inhibitors of Brucella abortus 2308 proliferation.
abstract: As bacterial pathogens develop resistance against most currently used antibiotics, novel alternatives for treatment of microbial infectious diseases are urgently needed. Targeting bacterial virulence functions in order to disarm pathogens represents a promising alternative to classical antibiotic therapy. Type IV secretion systems, which are multiprotein complexes in the cell envelope that translocate effectors into host cells, are critical bacterial virulence factors in many pathogens and excellent targets for such "antivirulence" drugs. The VirB8 protein from the mammalian pathogen Brucella was chosen as a specific target, since it is an essential type IV secretion system component, it participates in multiple protein-protein interactions, and it is essential for the assembly of this translocation machinery. The bacterial two-hybrid system was adapted to assay VirB8 interactions, and a high-throughput screen identified specific small-molecule inhibitors. VirB8 interaction inhibitors also reduced the levels of VirB8 and of other VirB proteins, and many of them inhibited virB gene transcription in Brucella abortus 2308, suggesting that targeting of the secretion system has complex regulatory effects in vivo. One compound strongly inhibited the intracellular proliferation of B. abortus 2308 in a J774 macrophage infection model. The results presented here show that in vivo screens with the bacterial two-hybrid assay are suited to the identification of inhibitors of Brucella type IV secretion system function.
authors.affiliation: McMaster University, Department of Pathology and Molecular Medicine and Juravinski Cancer Centre, 699 Concession Street, Hamilton, Ontario L8V 5C2, Canada.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Paschos
authors.forename: Andreas
authors.initials: A
authors.lastname: den Hartigh
authors.forename: Mark A
authors.initials: MA
authors.lastname: Smith
authors.forename: Vidya L
authors.initials: VL
authors.lastname: Atluri
authors.forename: Durga
authors.initials: D
authors.lastname: Sivanesan
authors.forename: Renée M
authors.initials: RM
authors.lastname: Tsolis
authors.forename: Christian
authors.initials: C
authors.lastname: Baron
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors*; D058947:Bacterial Secretion Systems / Q000187:drug effects*; D002003:Brucella abortus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002460:Cell Line; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology; D051379:Mice; D050296:Microbial Viability; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020798:Two-Hybrid System Techniques
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems