Zonulin
Endogenous protein that regulates intestinal tight-junction permeability and the molecular target of larazotide.
For laboratory and research use only — not for human consumption.
Zonulin was identified by Alessio Fasano's group as the eukaryotic homologue of Vibrio cholerae zonula occludens toxin. It modulates tight-junction permeability through engagement with EGFR and PAR2 receptors on intestinal epithelial cells, leading to ZO-1 redistribution and increased paracellular transport. Elevated serum and faecal zonulin levels are reported in coeliac disease and several other conditions associated with intestinal permeability changes. Larazotide is the principal pharmacological zonulin antagonist in research and has been studied in coeliac-disease clinical trials.