Maintenance of the epithelial barrier in a bronchial epithelial cell line is dependent on functional E-cadherin local to the tight junctions.

Journal article

Tight junctions (TJ) are essential components of polarized epithelia, and E-cadherin is important for their formation and maintenance. The bronchial epithelial cell line, 16HBE14o-expresses E- and P-cadherin, but not N-cadherin. E- and P-cadherin levels changed during culture, the former increasing after confluence, and the latter were markedly reduced. All detectable E-cadherin was bound to beta- and gamma-catenins. We investigated involvement of E-cadherin with epithelial integrity using an E-cadherin specific, function-blocking antibody, SHE78-7. Surprisingly, apical SHE78-7 exposure caused a prompt fall in transepithelial resistance (TER), while TER remained unchanged for 8 hrs after basal exposure then dropped. SHE78-7 exposure increased epithelial permeability to mannitol, inulin, and 9.5 kDa and 77 kDa dextrans and caused fragmentation and loss of the tight junction protein, ZO-1, from the cell borders in some areas. Ultrastructural studies showed that all junctional intercellular contact was lost in the center of SHE78-7 induced lesions. Near the lesion periphery, epithelial structure was maintained, but TJs were dysfunctional as shown by ruthenium red penetration. Analysis of epithelial penetration by SHE78-7 revealed discrete, local defects in the apical barrier at the top of some cell hills that permitted rapid access of the antibody to E-cadherin near the apical surface. In contrast, after basal exposure, antibody initially engaged with E-cadherin nearer the basal surface and only accessed apical E-cadherin later. Taken together with the TER measurements, these data suggest compartmentalization of E-cadherin function within 16HBE14o-cells, with only the apical E-cadherin adjacent to the tight junctions contributing to the function of the latter.

Authors: West, MR; Ferguson, D; Hart, V; Sanjar, S; Man, Y

• Journal: Cell communication and adhesion
• Volume: 9
• Issue: 1
• Pages: 29-44
• Publication date: 2002-01-01
• DOI: 10.1080/15419060212185
• EISSN: 1543-5180
• ISSN: 1541-9061
• Language: English
• Keywords: Humans; Immunohistochemistry; Dose-Response Relationship, Drug; Animals; Cytoskeletal Proteins; Mannitol; Rats; Cell Line; Bronchi; Blotting, Western; Time Factors; Epithelial Cells; Mice; Dextrans; Phosphoproteins; Inulin; Membrane Proteins; Ruthenium Red; Tight Junctions; Epithelium; Protein Binding; Immunoglobulin G; Cadherins