The bile salt glycocholate induces global changes in gene and protein expression and activates virulence in enterotoxigenic Escherichia coli

Sci Rep. 2019 Jan 14;9(1):108. doi: 10.1038/s41598-018-36414-z.

Abstract

Pathogenic bacteria use specific host factors to modulate virulence and stress responses during infection. We found previously that the host factor bile and the bile component glyco-conjugated cholate (NaGCH, sodium glycocholate) upregulate the colonization factor CS5 in enterotoxigenic Escherichia coli (ETEC). To further understand the global regulatory effects of bile and NaGCH, we performed Illumina RNA-Seq and found that crude bile and NaGCH altered the expression of 61 genes in CS5 + CS6 ETEC isolates. The most striking finding was high induction of the CS5 operon (csfA-F), its putative transcription factor csvR, and the putative ETEC virulence factor cexE. iTRAQ-coupled LC-MS/MS proteomic analyses verified induction of the plasmid-borne virulence proteins CS5 and CexE and also showed that NaGCH affected the expression of bacterial membrane proteins. Furthermore, NaGCH induced bacteria to aggregate, increased their adherence to epithelial cells, and reduced their motility. Our results indicate that CS5 + CS6 ETEC use NaGCH present in the small intestine as a signal to initiate colonization of the epithelium.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Adhesion
  • Caco-2 Cells
  • Cholagogues and Choleretics / metabolism*
  • Enterotoxigenic Escherichia coli / drug effects*
  • Enterotoxigenic Escherichia coli / pathogenicity
  • Epithelial Cells / microbiology
  • Escherichia coli Proteins / biosynthesis*
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial / drug effects*
  • Glycocholic Acid / metabolism*
  • Humans
  • Protein Biosynthesis / drug effects*
  • Proteome / analysis
  • Sequence Analysis, RNA
  • Virulence / drug effects

Substances

  • Cholagogues and Choleretics
  • Escherichia coli Proteins
  • Proteome
  • Glycocholic Acid