Deciphering molecular mechanism of silver by integrated omic approaches enables enhancing its antimicrobial efficacy in E. coli

PLoS Biol. 2019 Jun 10;17(6):e3000292. doi: 10.1371/journal.pbio.3000292. eCollection 2019 Jun.

Abstract

Despite the broad-spectrum antimicrobial activities of silver, its internal usage is restricted, owing to the toxicity. Strategies to enhance its efficacy are highly desirable but rely heavily on the understanding of its molecular mechanism of action. However, up to now, no direct silver-targeting proteins have been mined at a proteome-wide scale, which hinders systemic studies on the biological pathways interrupted by silver. Herein, we build up a unique system, namely liquid chromatography gel electrophoresis inductively coupled plasma mass spectrometry (LC-GE-ICP-MS), allowing 34 proteins directly bound by silver ions to be identified in Escherichia coli. By using integrated omic approaches, including metalloproteomics, metabolomics, bioinformatics, and systemic biology, we delineated the first dynamic antimicrobial actions of silver (Ag+) in E. coli, i.e., it primarily damages multiple enzymes in glycolysis and tricarboxylic acid (TCA) cycle, leading to the stalling of the oxidative branch of the TCA cycle and an adaptive metabolic divergence to the reductive glyoxylate pathway. It then further damages the adaptive glyoxylate pathway and suppresses the cellular oxidative stress responses, causing systemic damages and death of the bacterium. To harness these novel findings, we coadministrated metabolites involved in the Krebs cycles with Ag+ and found that they can significantly potentiate the efficacy of silver both in vitro and in an animal model. Our study reveals the comprehensive and dynamic mechanisms of Ag+ toxicity in E. coli cells and offers a novel and general approach for deciphering molecular mechanisms of metallodrugs in various pathogens and cells to facilitate the development of new therapeutics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Anti-Infective Agents
  • Bacteria
  • Chromatography, Liquid / methods
  • Computational Biology / methods*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / metabolism
  • Mass Spectrometry / methods
  • Metabolomics
  • Proteomics
  • Silver / metabolism*
  • Silver / therapeutic use*

Substances

  • Anti-Bacterial Agents
  • Anti-Infective Agents
  • Escherichia coli Proteins
  • Silver

Grants and funding

Research Grants Council of Hong Kong (17305415, 1733616, and 17307017), National Science Foundation of China (21671203), and the University of Hong Kong (for an e-SRT on Integrative Biology), as well as a Hong Kong PhD Fellowship (HKPF) for HW. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.