title: Tricellular Tight Junction Protein Tricellulin Is Targeted by the Enteropathogenic Escherichia coli Effector EspG1, Leading to Epithelial Barrier Disruption.
abstract: Enteropathogenic Escherichia coli (EPEC)-induced diarrhea is often associated with disruption of intestinal epithelial tight junctions. Although studies have shown alterations in the expression and localization of bicellular tight junction proteins during EPEC infections, little is known about whether tricellular tight junction proteins (tTJs) are affected. Using Caco-2 cell monolayers, we investigated if EPEC is capable of targeting the tTJ protein tricellulin. Our results demonstrated that at 4 h postinfection, EPEC induced a significant reduction in tricellulin levels, accompanied by a significant loss of transepithelial resistance (TEER) and a corresponding increase in paracellular permeability. Conversely, cells overexpressing tricellulin were highly resistant to EPEC-induced barrier disruption. Confocal microscopy revealed the distribution of tricellulin into the plasma membrane of infected epithelial cells and confirmed the localization of EPEC aggregates in close proximity to tTJs. Moreover, infections with EPEC strains lacking genes encoding specific type III secreted effector proteins demonstrated a crucial role for the effector EspG1 in modulating tricellulin expression. Complementation studies suggest that the EspG-induced depletion of tricellulin is microtubule dependent. Overall, our results show that EPEC-induced epithelial barrier dysfunction is mediated in part by EspG1-induced microtubule-dependent depletion of tricellulin.
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Vijay
authors: V
authors: Morampudi
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Franziska A
authors: FA
authors: Graef
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Martin
authors: M
authors: Stahl
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Udit
authors: U
authors: Dalwadi
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Victoria S
authors: VS
authors: Conlin
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Tina
authors: T
authors: Huang
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Bruce A
authors: BA
authors: Vallance
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.
authors: Hong B
authors: HB
authors: Yu
authors: Child and Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada kjacobson@cw.bc.ca.|Division of Gastroenterology, BC Children's Hospital, Vancouver, British Columbia, Canada.|Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Kevan
authors: K
authors: Jacobson
mesh_terms: D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D003967:Diarrhea / Q000378:metabolism / Q000382:microbiology; D054308:Enteropathogenic Escherichia coli / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism* / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000378:metabolism* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000378:metabolism*; D006801:Humans; D062794:MARVEL Domain Containing 2 Protein / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism / Q000382:microbiology; D010539:Permeability; D019108:Tight Junctions / Q000378:metabolism* / Q000382:microbiology
chemical_list: D029968:Escherichia coli Proteins; C000599182:EspG1 protein, E coli; D062794:MARVEL Domain Containing 2 Protein; D008869:Microtubule-Associated Proteins
keywords: EspG; enteropathogenic Escherichia coli; epithelial barrier function; tight junctions; tricellulin; type III secretion system; virulence