title: Downregulation of yidC in Escherichia coli by antisense RNA expression results in sensitization to antibacterial essential oils eugenol and carvacrol.
abstract: BACKGROUND
  The rising drug resistance in pathogenic bacteria and inefficiency of current antibiotics to meet clinical requirements has augmented the need to establish new and innovative approaches for antibacterial drug discovery involving identification of novel antibacterial targets and inhibitors. Being obligatory for bacterial growth, essential gene products are considered vital as drug targets. The bacterial protein YidC is highly conserved among pathogens and is essential for membrane protein insertion due to which it holds immense potential as a promising target for antibacterial therapy.
  
  
  RESULTS
  The aim of this study was to explore the feasibility and efficacy of expressed antisense-mediated gene silencing for specific downregulation of yidC in Escherichia coli. We induced RNA silencing of yidC which resulted in impaired growth of the host cells. This was followed by a search for antibacterial compounds sensitizing the YidC depleted cells as they may act as inhibitors of the essential protein or its products. The present findings affirm that reduction of YidC synthesis results in bacterial growth retardation, which warrants the use of this enzyme as a viable target in search of novel antibacterial agents. Moreover, yidC antisense expression in E. coli resulted in sensitization to antibacterial essential oils eugenol and carvacrol. Fractional Inhibitory Concentration Indices (FICIs) point towards high level of synergy between yidC silencing and eugenol/carvacrol treatment. Finally, as there are no known YidC inhibitors, the RNA silencing approach applied in this study put forward rapid means to screen novel potential YidC inhibitors.
  
  
  CONCLUSIONS
  The present results suggest that YidC is a promising candidate target for screening antibacterial agents. High level of synergy reported here between yidC silencing and eugenol/carvacrol treatment is indicative of a potential antibacterial therapy. This is the first report indicating that the essential gene yidC is a therapeutic target of the antibacterial essential oils eugenol and carvacrol in E. coli.
authors.affiliation: Chemical Biology and Drug Discovery Lab, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India.
authors.forename: Supriya Deepak
authors.initials: SD
authors.lastname: Patil
authors.forename: Rajnikant
authors.initials: R
authors.lastname: Sharma
authors.forename: Santosh
authors.initials: S
authors.lastname: Srivastava
authors.forename: Naveen Kumar
authors.initials: NK
authors.lastname: Navani
authors.forename: Ranjana
authors.initials: R
authors.lastname: Pathania
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015169:Colony Count, Microbial; D000081007:Cymenes; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D005054:Eugenol / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D020868:Gene Silencing; D020043:Genes, Essential; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D039821:Monoterpenes / Q000494:pharmacology*; D009822:Oils, Volatile / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D000081007:Cymenes; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D039821:Monoterpenes; D009822:Oils, Volatile; D034741:RNA, Small Interfering; C412443:YIDC protein, E coli; D005054:Eugenol; C073316:carvacrol