Journal Article

Membrane-anchored serine protease matriptase regulates epithelial barrier formation and permeability in the intestine

Netzel-Arnett, Sarah, Lin, Chen-Yong, Szabo, Roman, Zhao, Aiping, Shea-Donohue, Terez, Bugge, Thomas H, Antalis, Toni M, List, Karin, Buzza, Marguerite S, Fasano, Alessio

2010

Overview

The intestinal epithelium serves as a major protective barrier between the mammalian host and the external environment. Here we show that the transmembrane serine protease matriptase plays a pivotol role in the formation and integrity of the intestinal epithelial barrier. St14 hypomorphic mice, which have a 100-fold reduction in intestinal matriptase mRNA levels, display a 35% reduction in intestinal transepithelial electrical resistance (TEER). Matriptase is expressed during intestinal epithelial differentiation and colocalizes with E-cadherin to apical junctional complexes (AJC) in differentiated polarized Caco-2 monolayers. Inhibition of matriptase activity using a specific peptide inhibitor or by knockdown of matriptase by siRNA disrupts the development of TEER in barrier-forming Caco-2 monolayers and increases paracellular permeability to macromolecular FITC-dextran. Loss of matriptase was associated with enhanced expression and incorporation of the permeability-associated, \"leaky\" tight junction protein claudin-2 at intercellular junctions. Knockdown of claudin-2 enhanced the development of TEER in matriptase-silenced Caco-2 monolayers, suggesting that the reduced barrier integrity was caused, at least in part, by an inability to regulate claudin-2 expression and incorporation into junctions. We find that matriptase enhances the rate of claudin-2 protein turnover, and that this is mediated indirectly through an atypical PKCζ-dependent signaling pathway. These results support a key role for matriptase in regulating intestinal epithelial barrier competence, and suggest an intriguing link between pericellular serine protease activity and tight junction assembly in polarized epithelia.

• Publisher: National Academy of Sciences,National Acad Sciences
• Subject: Biological Sciences / Caco 2 cells / cadherins / Calcium / Cell lines / Cell Membrane - enzymology / Cell Proliferation / Claudins / electrical resistance / enzyme activity / Epithelial cells / Gene expression regulation / Gene Silencing / Humans / intestinal mucosa / Intestinal Mucosa - metabolism / Large intestine / Membrane Proteins - metabolism / Membranes / Messenger RNA / mice / Permeability / Physiological regulation / Proteases / Protein Kinase C - metabolism / protein metabolism / Proteins / Ribonucleic acid / RNA / RNA, Small Interfering / Rodents / Serine Endopeptidases - genetics / Serine Endopeptidases - metabolism / serine proteinases / Signal Transduction / Small interfering RNA / Small intestine / Tight junctions