Inhibition of Heat-Stable Toxin-Induced Intestinal Salt and Water Secretion by a Novel Class of Guanylyl Cyclase C Inhibitors

J Infect Dis. 2015 Dec 1;212(11):1806-15. doi: 10.1093/infdis/jiv300. Epub 2015 May 21.


Background: Many enterotoxigenic Escherichia coli strains produce the heat-stable toxin, STa, which, by activation of the intestinal receptor-enzyme guanylyl cyclase (GC) C, triggers an acute, watery diarrhea. We set out to identify GCC inhibitors that may be of benefit for the treatment of infectious diarrheal disease.

Methods: Compounds that inhibit STa-induced cyclic guanosine 3',5'-monophosphate (cGMP) production were selected by performing cyclase assays on cells and membranes containing GCC, or the related GCA. The effect of leads on STa/GCC-dependent activation of the cystic fibrosis transmembrane conductance regulator anion channel was investigated in T84 cells, and in porcine and human intestinal tissue. Their effect on STa-provoked fluid transport was assessed in ligated intestinal loops in piglets.

Results: Four N-2-(propylamino)-6-phenylpyrimidin-4-one-substituted piperidines were shown to inhibit GCC-mediated cellular cGMP production. The half maximal inhibitory concentrations were ≤ 5 × 10(-7) mol/L, whereas they were >10 times higher for GCA. In T84 monolayers, these leads blocked STa/GCC-dependent, but not forskolin/adenylyl cyclase-dependent, cystic fibrosis transmembrane conductance regulator activity. GCC inhibition reduced STa-provoked anion secretion in pig jejunal tissue, and fluid retention and cGMP levels in STa-exposed loops. These GCC inhibitors blocked STa-provoked anion secretion in rectal biopsy specimens.

Conclusions: We have identified a novel class of GCC inhibitors that may form the basis for development of future therapeutics for (infectious) diarrheal disease.

Keywords: CFTR; enterotoxigenic E. coli (ETEC); guanylyl cyclase C; secretory diarrhea.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylyl Cyclases / metabolism
  • Adult
  • Animals
  • Bacterial Toxins / antagonists & inhibitors*
  • Bacterial Toxins / metabolism
  • Cystic Fibrosis Transmembrane Conductance Regulator / antagonists & inhibitors
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
  • Diarrhea
  • Enterotoxigenic Escherichia coli
  • Enterotoxins / antagonists & inhibitors*
  • Enterotoxins / metabolism
  • Enzyme Inhibitors / pharmacology*
  • Escherichia coli Proteins / antagonists & inhibitors*
  • Escherichia coli Proteins / metabolism
  • HeLa Cells
  • Humans
  • Jejunum / cytology
  • Jejunum / drug effects*
  • Jejunum / metabolism
  • Models, Biological
  • Piperidines / pharmacology*
  • Receptors, Enterotoxin
  • Receptors, Guanylate Cyclase-Coupled / antagonists & inhibitors*
  • Receptors, Guanylate Cyclase-Coupled / metabolism
  • Receptors, Peptide / antagonists & inhibitors*
  • Receptors, Peptide / metabolism
  • Signal Transduction / drug effects
  • Swine
  • Young Adult


  • Bacterial Toxins
  • Enterotoxins
  • Enzyme Inhibitors
  • Escherichia coli Proteins
  • Piperidines
  • Receptors, Peptide
  • heat stable toxin (E coli)
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Adenylyl Cyclases
  • Receptors, Enterotoxin
  • Receptors, Guanylate Cyclase-Coupled