Potential novel antibiotics from HTS targeting the virulence-regulating transcription factor, VirF, from Shigella flexneri.

Abstract

VirF is an AraC-type transcriptional regulator responsible for activating the transcription of virulence genes required for the intracellular invasion and cell-to-cell spread of Shigella flexneri. Gene disruption studies have validated VirF as a potential target for an anti-virulence therapy to treat shigellosis by determining that VirF is necessary for virulence, but not required for bacterial viability. Using a bacteria-based, β-galactosidase reporter assay we completed a high-throughput screening (HTS) campaign monitoring VirF activity in the presence of over 140,000 small molecules. From our screening campaign, we identified five lead compounds to pursue in tissue culture-based invasion and cell-to-cell spread assays, and toxicity screens. Our observations of activity in these models for infection have validated our approach of targeting virulence regulation and have allowed us to identify a promising chemical scaffold from our HTS for hit-to-lead development. Interestingly, differential effects on invasion versus cell-to-cell spread suggest that the compounds' efficacies may depend, in part, on the specific promoter that VirF is recognizing.

• Authors: Anthony A Emanuele, Nancy E Adams, Yi-Chen Chen, Anthony T Maurelli, George A Garcia
• Journal: The Journal of antibiotics (J Antibiot (Tokyo)) Vol. 67 Issue 5 Pg. 379-86 (May 2014) ISSN: 1881-1469 [Electronic] England
• PMID: 24549153 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Bacterial Agents
• Indicators and Reagents
• Interferon Regulatory Factors
• Viral Proteins
• Virulence Factors
• viral interferon regulatory factors
• beta-Galactosidase

Topics

• Algorithms
• Anti-Bacterial Agents (isolation & purification, pharmacology)
• Data Interpretation, Statistical
• Genes, Reporter (genetics)
• HeLa Cells
• High-Throughput Screening Assays (methods)
• Humans
• Indicators and Reagents
• Interferon Regulatory Factors (drug effects)
• Microbial Sensitivity Tests
• Plasmids (genetics)
• Reproducibility of Results
• Shigella flexneri (drug effects, genetics, growth & development)
• Viral Proteins (drug effects)
• Virulence (genetics)
• Virulence Factors
• beta-Galactosidase (genetics)