Cyclic stretch induces alveolar epithelial barrier dysfunction via calpain-mediated degradation of p120-catenin.

Abstract

Lung hyperinflation is known to be an important contributing factor in the pathogenesis of ventilator-induced lung injury. Mechanical stretch causes epithelial barrier dysfunction and an increase in alveolar permeability, although the precise mechanisms have not been completely elucidated. p120-catenin is an adherens junction-associated protein that regulates cell-cell adhesion. In this study, we determined the role of p120-catenin in cyclic stretch-induced alveolar epithelial barrier dysfunction. Cultured alveolar epithelial cells (MLE-12) were subjected to uniform cyclic (0.5 Hz) biaxial stretch from 0 to 8 or 20% change in surface area for 0, 1, 2, or 4 h. At the end of the experiments, cells were lysed to determine p120-catenin expression by Western blot analysis. Immunofluorescence staining of p120-catenin and F-actin was performed to assess the integrity of monolayers and interepithelial gap formation. Compared with unstretched control cells, 20% stretch caused a significant loss in p120-catenin expression, which was coupled to interepithelial gap formation. p120-Catenin knockdown with small interfering RNA (siRNA) dose dependently increased stretch-induced gap formation, whereas overexpression of p120-catenin abolished stretch-induced gap formation. Furthermore, pharmacological calpain inhibition or depletion of calpain-1 with a specific siRNA prevented p120-catenin loss and subsequent stretch-induced gap formation. Our findings demonstrate that p120-catenin plays a critical protective role in cyclic stretch-induced alveolar barrier dysfunction, and, thus, maintenance of p120-catenin expression may be a novel therapeutic strategy for the prevention and treatment of ventilator-induced lung injury.

• Authors: Yuelan Wang, Richard D Minshall, David E Schwartz, Guochang Hu
• Journal: American journal of physiology. Lung cellular and molecular physiology (Am J Physiol Lung Cell Mol Physiol) Vol. 301 Issue 2 Pg. L197-206 (Aug 2011) ISSN: 1522-1504 [Electronic] United States
• PMID: 21571907 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Catenins
• RNA, Small Interfering
• Calpain
• Delta Catenin
• Ctnnd1 protein, mouse

Topics

• Animals
• Blood-Air Barrier (physiopathology)
• Blotting, Western
• Calpain (antagonists & inhibitors, genetics, metabolism)
• Catenins (genetics, metabolism)
• Cell Line
• Dose-Response Relationship, Drug
• Epithelial Cells
• Epithelium (pathology, physiopathology)
• Fluorescent Antibody Technique
• Intracellular Space
• Mice
• Pulmonary Alveoli (pathology, physiopathology)
• RNA, Small Interfering (administration & dosage)
• Staining and Labeling
• Stress, Physiological
• Transfection
• Up-Regulation
• Delta Catenin