Inhibition of suilysin activity and inflammation by myricetin attenuates Streptococcus suis virulence

Life Sci. 2019 Apr 15:223:62-68. doi: 10.1016/j.lfs.2019.03.024. Epub 2019 Mar 11.

Abstract

Streptococcus suis (S. suis) is a gram-positive, zoonotic pathogenic bacterium that poses a serious threat to the pig industry and human health. This globally distributed pathogen can cause multiple diseases and fatal infections in both humans and animals. Suilysin (SLY) is an important extracellular secreted toxin regarded as an essential S. suis capsular type 2 (SS2) virulence factor and plays a key role in the infection and cytotoxicity of SS2. In addition, an excessive inflammatory response is also a serious hazard caused by SS2 infection. In this study, we demonstrated that the natural compound myricetin can inhibit the hemolytic activity of SLY and is effective at reducing the production of the inflammatory cytokines TNF-α and IL-1β and reducing inflammation by downregulating the activation of P38. In addition, myricetin could effectively treat SS2 infections in vitro and in vivo. These findings may aid in the development of promising therapeutic candidates for treating SS2 infections.

Keywords: Antivrulence; Inflamation; Myricetin; Streptococcus suis; Suilysin.

MeSH terms

  • Animals
  • Cell Line
  • Cell Survival / drug effects
  • Disease Models, Animal
  • Female
  • Flavonoids / pharmacology*
  • Hemolysin Proteins / antagonists & inhibitors*
  • Inflammation
  • Macrophages / drug effects
  • Macrophages / immunology
  • Macrophages / microbiology
  • Mice, Inbred C57BL
  • Microbial Sensitivity Tests
  • Streptococcal Infections / drug therapy*
  • Streptococcal Infections / immunology
  • Streptococcal Infections / microbiology
  • Streptococcus suis / drug effects*
  • Streptococcus suis / metabolism
  • Streptococcus suis / pathogenicity
  • Virulence
  • Virulence Factors / antagonists & inhibitors*

Substances

  • Flavonoids
  • Hemolysin Proteins
  • Virulence Factors
  • suilysin
  • myricetin