title: Mutation of EpCAM leads to intestinal barrier and ion transport dysfunction.
abstract: Congenital tufting enteropathy (CTE) is a devastating diarrheal disease seen in infancy that is typically associated with villous changes and the appearance of epithelial tufts. We previously found mutations in epithelial cell adhesion molecule (EpCAM) to be causative in CTE. We developed a knock-down cell model of CTE through transfection of an EpCAM shRNA construct into T84 colonic epithelial cells to elucidate the in vitro role of EpCAM in barrier function and ion transport. Cells with EpCAM deficiency exhibited decreased electrical resistance, increased permeability, and decreased ion transport. Based on mutations in CTE patients, an in vivo mouse model was developed, with tamoxifen-inducible deletion of exon 4 in Epcam resulting in mutant protein with decreased expression. Tamoxifen treatment of Epcam (Δ4/Δ4) mice resulted in pathological features of villous atrophy and epithelial tufts, similar to those in human CTE patients, within 4 days post induction. Epcam (Δ4/Δ4) mice also showed decreased expression of tight junctional proteins, increased permeability, and decreased ion transport in the intestines. Taken together, these findings reveal mechanisms that may underlie disease in CTE.
  
  
  CONCLUSIONS
  Knock-down EpCAM cell model of congenital tufting enteropathy was developed. In vivo inducible mouse model was developed resulting in mutant EpCAM protein. Cells with EpCAM deficiency demonstrated barrier and ion transport dysfunction. Tamoxifen-treated Epcam (Δ4/Δ4) mice demonstrated pathological features. Epcam (Δ4/Δ4) mice showed improper barrier function and ion transport.
authors.affiliation: Division of Gastroenterology, Department of Medicine, University of California San Diego, San Diego, CA, USA.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Kozan
authors.forename: Matthew D
authors.initials: MD
authors.lastname: McGeough
authors.forename: Carla A
authors.initials: CA
authors.lastname: Peña
authors.forename: James L
authors.initials: JL
authors.lastname: Mueller
authors.forename: Kim E
authors.initials: KE
authors.lastname: Barrett
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Marchelletta
authors.forename: Mamata
authors.initials: M
authors.lastname: Sivagnanam
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics* / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D000071858:Epithelial Cell Adhesion Molecule; D055785:Gene Knockdown Techniques; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D017136:Ion Transport; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D010539:Permeability; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D034741:RNA, Small Interfering