Ohmyungsamycins promote antimicrobial responses through autophagy activation via AMP-activated protein kinase pathway

Sci Rep. 2017 Jun 13;7(1):3431. doi: 10.1038/s41598-017-03477-3.

Abstract

The induction of host cell autophagy by various autophagy inducers contributes to the antimicrobial host defense against Mycobacterium tuberculosis (Mtb), a major pathogenic strain that causes human tuberculosis. In this study, we present a role for the newly identified cyclic peptides ohmyungsamycins (OMS) A and B in the antimicrobial responses against Mtb infections by activating autophagy in murine bone marrow-derived macrophages (BMDMs). OMS robustly activated autophagy, which was essentially required for the colocalization of LC3 autophagosomes with bacterial phagosomes and antimicrobial responses against Mtb in BMDMs. Using a Drosophila melanogaster-Mycobacterium marinum infection model, we showed that OMS-A-induced autophagy contributed to the increased survival of infected flies and the limitation of bacterial load. We further showed that OMS triggered AMP-activated protein kinase (AMPK) activation, which was required for OMS-mediated phagosome maturation and antimicrobial responses against Mtb. Moreover, treating BMDMs with OMS led to dose-dependent inhibition of macrophage inflammatory responses, which was also dependent on AMPK activation. Collectively, these data show that OMS is a promising candidate for new anti-mycobacterial therapeutics by activating antibacterial autophagy via AMPK-dependent signaling and suppressing excessive inflammation during Mtb infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinase Kinases
  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Autophagy*
  • Cells, Cultured
  • Humans
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Macrophages / microbiology
  • Mice
  • Mice, Inbred C57BL
  • Mycobacterium Infections / drug therapy*
  • Mycobacterium tuberculosis / drug effects
  • Mycobacterium tuberculosis / pathogenicity
  • Peptides, Cyclic / pharmacology*
  • Peptides, Cyclic / therapeutic use
  • Protein Kinases / metabolism*
  • Streptomyces / drug effects
  • Streptomyces / pathogenicity

Substances

  • Anti-Bacterial Agents
  • Peptides, Cyclic
  • ohmyungsamycin A
  • ohmyungsamycin B
  • Protein Kinases
  • AMP-Activated Protein Kinase Kinases