Effect of honokiol on exotoxin proteins listeriolysin O and p60 secreted by Listeria monocytogenes

J Med Microbiol. 2015 Dec;64(12):1474-1480. doi: 10.1099/jmm.0.000183. Epub 2015 Oct 6.

Abstract

Listeria monocytogenes is considered one of the most important foodborne pathogens. The virulence-related proteins listeriolysin O (LLO) and p60 are critical factors involved in Listeria pathogenesis. In the present study, we investigated the effect of honokiol on LLO and p60 secreted from L. monocytogenes. A listeriolysin assay was used to investigate the haemolytic activities of L. monocytogenes exposed to honokiol, and the secretion of LLO and p60 was detected by immunoblot analysis. Additionally, the influence of honokiol on the transcription of LLO and p60 genes (hly and iap, respectively) was analysed by real-time reverse transcription PCR. TNF-α release assays were performed to elucidate the biological relevance of changes in LLO and p60 secretion induced by honokiol. According to the data, honokiol showed good anti-L. monocytogenes activity, with MICs of 8-16 μg ml(-1), and the secretion of LLO and p60 was decreased by honokiol. In addition, the transcription of hly and iap was inhibited by honokiol. Our results indicate that TNF-α production by RAW264.7 cells stimulated with L. monocytogenes supernatants was inhibited by honokiol. Based on these data, we propose that honokiol could be used as a promising natural compound against L. monocytogenes and its virulence factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Infective Agents / pharmacology*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Bacterial Toxins / chemistry
  • Bacterial Toxins / genetics
  • Bacterial Toxins / metabolism*
  • Biphenyl Compounds / pharmacology*
  • Cell Line
  • Gene Expression Regulation, Bacterial / drug effects*
  • Heat-Shock Proteins / chemistry
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism*
  • Hemolysin Proteins / chemistry
  • Hemolysin Proteins / genetics
  • Hemolysin Proteins / metabolism*
  • Lignans / pharmacology*
  • Listeria monocytogenes / drug effects*
  • Listeria monocytogenes / genetics
  • Listeria monocytogenes / metabolism
  • Macrophages / metabolism
  • Macrophages / microbiology
  • Mice
  • Microbial Sensitivity Tests
  • Milk / chemistry
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • 60 kDa protein, Listeria monocytogenes
  • Anti-Infective Agents
  • Bacterial Proteins
  • Bacterial Toxins
  • Biphenyl Compounds
  • Heat-Shock Proteins
  • Hemolysin Proteins
  • Lignans
  • Tumor Necrosis Factor-alpha
  • honokiol
  • hlyA protein, Listeria monocytogenes