Influence of a high-glucose diet on the sensitivity of Caenorhabditis elegans towards Escherichia coli and Staphylococcus aureus strains

Microbes Infect. Jul-Aug 2013;15(8-9):540-9. doi: 10.1016/j.micinf.2013.04.006. Epub 2013 Apr 30.

Abstract

It was recently observed that a glucose-enriched diet activates the insulin-like pathway in Caenorhabditis elegans, resulting in an inhibition of the FOXO transcription factor DAF-16. Because this signalling pathway is highly conserved from invertebrates to mammals and DAF-16 is a key player in innate immunity, we wondered whether a high-glucose diet, resembling the hyperglycaemic conditions in diabetic patients, would affect the susceptibility of C. elegans to bacterial pathogens isolated from different clinical situations (urinary tract or diabetic foot infections). We confirmed previous reports showing that such a diet decreases the lifespan of C. elegans fed with an avirulent Escherichia coli strain. However, glucose-fed nematodes appeared to be more resistant to most clinical isolates tested, showing that this invertebrate model does not mimic infections encountered in human diabetes, where patients show increased susceptibility to bacterial infections. This study also suggests that modulation of innate immunity in C. elegans, upon activation of the IGF1/insulin-like pathway by glucose, is not exclusively mediated by DAF-16, but also involves an additional factor that requires DAF-16 activity.

Keywords: Caenorhabditis elegans; DAF-16; Diabetes mellitus; Escherichia coli; Staphylococcus aureus; Virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / immunology
  • Caenorhabditis elegans / microbiology*
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / metabolism
  • Diabetes Complications / immunology
  • Diet / methods*
  • Disease Models, Animal
  • Disease Susceptibility
  • Escherichia coli Infections / immunology*
  • Forkhead Transcription Factors
  • Gene Expression Regulation
  • Glucose / metabolism*
  • Staphylococcal Infections / immunology*
  • Survival Analysis
  • Transcription Factors / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Forkhead Transcription Factors
  • Transcription Factors
  • daf-16 protein, C elegans
  • Glucose