Selective disruption of cadherin/catenin complexes by oxidative stress in precision-cut mouse liver slices.
Previous work has shown that chemically induced oxidative stress disrupts the protein interactions of the E-cadherin/beta-catenin/alpha-catenin complex in precision-cut mouse liver slices (Parrish et al., 1999, Toxicol. Sci. 51, 80-86). Although these data suggest a role for oxidative stress in disruption of hepatic cadherin/catenin complexes, multiple complexes are co-expressed in the liver. Both E- and N- cadherin are co-expressed in hepatocytes, as well as beta-catenin and gamma-catenin; thus four distinct complexes mediate cell-cell adhesion in the liver: E-cadherin/beta-catenin/alpha-catenin, E-cadherin/gamma-catenin/alpha-catenin, N-cadherin/beta-catenin/alpha-catenin, and N-cadherin/gamma-catenin/alpha-catenin. Taking advantage of the retention of normal organ architecture and cellular heterogeneity offered by precision-cut mouse liver slices, the current study was designed to examine the impact of chemically induced oxidative stress on cadherin/catenin complexes. Precision-cut mouse liver slices were challenged with diamide (25-250 microM; 6 h) or tert-butylhydroperoxide (5-50 microM; 6 h). A polyclonal antibody against beta- or gamma-catenin was used to immunoprecipitate proteins prior to Western-blot analysis with monoclonal antibodies to E- or N-cadherin. Although a decrease in E-cadherin:beta-catenin co-immunoprecipitation was seen, interactions between beta-catenin and N-cadherin were not disrupted by chemical challenge. In addition, no effect on protein interactions of gamma-catenin with either cadherin was observed. Indirect immunofluorescence was used to co-localize catenins and cadherins following chemical challenge. Consistent with the biochemical observations, a heterogeneous reduction in co-localization of E-cadherin and beta-catenin was seen in precision-cut liver slices, but not other cadherin/catenin complexes. Taken together, these data suggest that oxidative stress selectively disrupts E-cadherin/beta-catenin complexes in the liver. This response is dictated, in part, by the protein composition of the cell-adhesion complex.
Schmelz
M
M
Department of Pathology, College of Medicine, University of Arizona, Tucson, Arizona, USA.
Schmid
V J
VJ
Parrish
A R
AR
D000818:Animals; D015153:Blotting, Western; D015820:Cadherins / Q000378:metabolism*; D002448:Cell Adhesion / Q000187:drug effects; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D051180:Desmoplakins; D003958:Diamide / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018613:Microscopy, Confocal; D018384:Oxidative Stress; D011233:Precipitin Tests; D012680:Sensitivity and Specificity; D015534:Trans-Activators; D051176:beta Catenin; D051185:gamma Catenin; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
C495267:CTNNB1 protein, mouse; D015820:Cadherins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; C495293:Jup protein, mouse; D015534:Trans-Activators; D051176:beta Catenin; D051185:gamma Catenin; D003958:Diamide; D020122:tert-Butylhydroperoxide