p120-catenin is essential for maintenance of barrier function and intestinal homeostasis in mice
Whitney G. Smalley-Freed, … , Robert J. Coffey, Albert B. Reynolds
Whitney G. Smalley-Freed, … , Robert J. Coffey, Albert B. Reynolds
Published May 17, 2010
Citation Information: J Clin Invest. 2010;120(6):1824-1835. https://doi.org/10.1172/JCI41414.
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Research Article Gastroenterology

p120-catenin is essential for maintenance of barrier function and intestinal homeostasis in mice

Abstract

Epithelial-cadherin (E-cadherin) is a master organizer of the epithelial phenotype. Its function is regulated in part by p120-catenin (referred to herein as p120), a cytoplasmic binding partner that directly regulates cadherin stability. As it has been suggested that cadherins have a role in inflammatory bowel disease (IBD), we sought to investigate this further by assessing the effect of p120 deficiency in mouse small intestine and colon. p120 conditional KO mice were superficially normal at birth but declined rapidly and died within 21 days. Cell-cell adhesion defects and inflammation led to progressive mucosal erosion and terminal bleeding, similar to what is observed in a dominant-negative cadherin mouse model of IBD. Additionally, selective loss of adherens junctions and accumulation of atypical COX-2–expressing neutrophils in p120-null areas of the colon were observed. To elucidate the mechanism, direct effects of p120 deficiency were assessed in vitro in a polarizing colon cancer cell line. Notably, transepithelial electrical resistance was dramatically reduced, neutrophil binding was increased 30 fold, and levels of COX-2, an enzyme associated with IBD, were markedly increased in neutrophils. Our data suggest that p120 loss disrupts the neonatal intestinal barrier and amplifies neutrophil engagement and that these changes lead to catastrophic inflammation during colonization of the neonatal gut with bacteria and other luminal antigens. Thus, we conclude that p120 has an essential role in barrier function and epithelial homeostasis and survival in the intestine.

Authors

Whitney G. Smalley-Freed, Andrey Efimov, Patrick E. Burnett, Sarah P. Short, Michael A. Davis, Deborah L. Gumucio, M. Kay Washington, Robert J. Coffey, Albert B. Reynolds

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Figure 9

COX-2 is upregulated in neutrophils after exposure to p120-deficient HCA7 monolayers.

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COX-2 is upregulated in neutrophils after exposure to p120-deficient HCA...
(A) Neutrophil transmigration experiments were conducted as described in Figure 5, except that the incubation time was either 2 hours or 18 hours. After vigorous washing, filters were costained for myeloperoxidase (neutrophils) and COX-2. As also observed at 2 hours (Figure 5), neutrophil attachment to p120-deficient monolayers (pLL-hp120i-GFP) was substantially increased relative to that of control (pLL-GFP). However, there is no upregulation of COX-2 at 2 hours (bottom middle panel). Original magnification, ×20. (B) Quantification of neutrophil attachment and COX-2 upregulation at 18 hours Neutrophils were divided into 3 groups based on COX-2 staining intensity. Neutrophils with COX-2 staining lower than that of background levels (18% of maximum intensity) were considered COX-2 negative, neutrophils with COX-2 staining between 18% and 35% of maximum intensity were considered COX-2 low, and neutrophils with higher than 35% of maximum COX-2 intensity were considered COX-2 high. We found that 62.71% of the neutrophils attached to p120-deficient monolayers have high COX-2 staining. In contrast, only 10.59% of the neutrophils attached to WT monolayers have high COX-2 staining. Data represent mean ± SD.