Role of E-cadherin in the pathogenesis of gastroesophageal reflux disease.

Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.
The American Journal of Gastroenterology (Impact Factor: 9.21). 03/2011; 106(6):1039-47. DOI: 10.1038/ajg.2011.102
Source: PubMed

ABSTRACT An early event in the pathogenesis of gastroesophageal reflux disease (GERD) is an acid-induced increase in junctional (paracellular) permeability in esophageal epithelium (EE). The molecular events that account for this change are unknown. E-cadherin is a junctional protein important in barrier function in EE. Therefore, defects in barrier function in EE were sought in GERD as well as whether their presence correlated with abnormalities in e-cadherin.
Endoscopic biopsies of EE from GERD (n=20; male 10; female 10; mean age 50 ± 10 years) and subjects with a healthy esophagus (controls; n=23; male 11; female 12; mean age 51 ± 11 years) were evaluated in mini-Ussing chambers and by western blot and immunochemistry; and serum analyzed by enzyme-linked immunosorbent assay (ELISA). A role for e-cadherin was also assessed using a unique conditional knockout of e-cadherin in adult mouse esophagus.
EE from GERD patients had lower electrical resistance and higher fluorescein flux than EE from controls; and the findings in GERD associated with cleavage of e-cadherin. Cleavage of e-cadherin in GERD was documented in EE by the presence of a 35-kDa, C-terminal fragment of the molecule on western blot and by an increase in soluble N-terminal fragments of the molecule in serum. Activation of the membrane metalloproteinase, A Disintegrin And Metalloproteinase (ADAM-10), was identified as a likely cause for cleavage of e-cadherin by western blot and immunostaining and a role for e-cadherin in the increased junctional permeability in EE from GERD supported by showing increased permeability after deletion of e-cadherin in mouse EE.
The EE in GERD has increased junctional permeability and this is in association with proteolytic cleavage of e-cadherin. As loss of e-cadherin can, alone, account for the increase in junctional permeability, cleavage of e-cadherin likely represents a critical molecular event in the pathogenesis of GERD, and identification of cleaved fragments may, if confirmed in larger studies, be valuable as a biomarker of GERD.

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