Membrane-anchored serine protease matriptase regulates epithelial barrier formation and permeability in the intestine.
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 PKCzeta-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.
Buzza
Marguerite S
MS
Department of Physiology, Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Netzel-Arnett
Sarah
S
Shea-Donohue
Terez
T
Zhao
Aiping
A
Lin
Chen-Yong
CY
List
Karin
K
Szabo
Roman
R
Fasano
Alessio
A
Bugge
Thomas H
TH
Antalis
Toni M
TM
D018938:Caco-2 Cells; D002462:Cell Membrane / Q000201:enzymology; D049109:Cell Proliferation; D057167:Claudins; D020868:Gene Silencing; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D010539:Permeability; D011493:Protein Kinase C / Q000378:metabolism; D034741:RNA, Small Interfering; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D000099221:Protein Kinase C zeta
D057167:Claudins; D008565:Membrane Proteins; D011493:Protein Kinase C; D034741:RNA, Small Interfering; D012697:Serine Endopeptidases; D000099221:Protein Kinase C zeta; C491875:CLDN2 protein, human; C485595:matriptase