Aberrant cell migration contributes to defective airway epithelial repair in childhood wheeze

JNK is a nonreceptor kinase involved in the early events that signal cell migration after injury. However, the linkage to early signals required to initiate the migration response to JNK has not been defined in airway epithelial cells, which exist in an environment subjected to cyclic mechanical strain (MS). The present studies demonstrate that the JNK/stress-activated protein kinase-associated protein 1 (JSAP1; also termed JNK-interacting protein 3, JIP3), a scaffold factor for MAPK cascades that links JNK activation to focal adhesion kinase (FAK), are both associated and activated following mechanical injury in 16HBE14o− human airway epithelial cells and that both FAK and JIP3 phosphorylation seen after injury are decreased in cells subjected to cyclic MS. Overexpression of either wild-type (WT)-FAK or WT-JIP3 enhanced phosphorylation and kinase activation of JNK and reduced the inhibitory effect of cyclic MS. These results suggest that cyclic MS impairs signaling of cell migration after injury via a pathway that involves FAK-JIP3-JNK.

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Epithelial repair is inhibited by an α1,6-fucose binding lectin

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00292.2006 ◽

2007 ◽

Vol 292 (2) ◽

pp. L462-L468 ◽

Cited By ~ 4

Author(s):

Elizabeth C. Adam ◽

Stephen T. Holgate ◽

Peter M. Lackie

Keyword(s):

Binding Sites ◽

Repair Process ◽

Airway Epithelial ◽

Free Medium ◽

Epithelial Repair ◽

Aleuria Aurantia Lectin ◽

Cell Substrate ◽

Binding Lectin ◽

Aleuria Aurantia ◽

Insight Into

The effective repair of damage to the airway epithelium is essential to maintain the ability to exclude airborne particulates and protect against potential pathogens. Carbohydrates on the cell surface have an important role in cell-cell and cell substrate interactions. Using a model of repair with airway epithelial-derived cells of the 16HBE 14o− cell line, we have examined the effect of the Aleuria aurantia lectin (AAL), which binds very selectively to α1,6-linked fucose residues. Addition of unconjugated or FITC-labeled AAL reduced the rate of epithelial repair to approximately one-third of control values as measured by image analysis while cell viability was maintained. Pulse labeling with AAL-FITC for 30 min followed by incubation in AAL-free medium caused similar inhibition of repair but could be reversed by addition of fucose up to 7 h after AAL removal. By confocal microscopy, AAL binding was found to be on the apical, but not basolateral, surfaces of cells, and internalization of the labeled lectin was seen. Preincubation of the lectin with fucose prevented this effect. Ulex europeaus I lectin, which is also fucose specific, resulted in similar binding to the cells and internalization, but it did not affect the speed of the repair process. We conclude that α1,6-fucose binding sites play an important role in epithelial repair. Better understanding of this process will provide a deeper insight into the crucial mechanisms of epithelial repair.

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Effects of corticosteroid-induced apoptosis on airway epithelial wound closure in vitro

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00322.2005 ◽

2006 ◽

Vol 291 (4) ◽

pp. L794-L801 ◽

Cited By ~ 18

Author(s):

Delbert R. Dorscheid ◽

Benjamin J. Patchell ◽

Oscar Estrada ◽

Bertha Marroquin ◽

Roberta Tse ◽

...

Keyword(s):

Cell Migration ◽

Epithelial Cell ◽

Epithelial Cells ◽

Untreated Control ◽

Wound Closure ◽

Airway Epithelial Cell ◽

Airway Epithelial ◽

Wound Area ◽

Epithelial Cell Migration

Damage to the airway epithelium is common in asthma. Corticosteroids induce apoptosis in and suppress proliferation of airway epithelial cells in culture. Whether apoptosis contributes to impaired epithelial cell repair after injury is not known. We examined whether corticosteroids would impair epithelial cell migration in an in vitro model of wound closure. Wounds (∼0.5–1.3 mm2) were created in cultured 1HAEo−human airway epithelial cell monolayers, after which cells were treated with up to 10 μM dexamethasone or budesonide for 24 h. Cultured cells were pretreated for 24 or 48 h with dexamethasone to observe the effect of long-term exposure on wound closure. After 12 h, the remaining wound area in monolayers pretreated for 48 h with 10 μM dexamethasone was 43 ± 18% vs. 10 ± 8% for untreated control monolayers. The addition of either corticosteroid immediately after injury did not slow closure significantly. After 12 h the remaining wound area in monolayers treated with 10 μM budesonide was 39 ± 4% vs. 43 ± 3% for untreated control monolayers. The proportion of apoptotic epithelial cells as measured by terminal deoxynucleotidyltransferase-mediated dUTP biotin nick end labeling both at and away from the wound edge was higher in monolayers treated with budesonide compared with controls. However, wound closure in the apoptosis-resistant 1HAEo−.Bcl-2+cell line was not different after dexamethasone treatment. We demonstrate that corticosteroid treatment before mechanical wounding impairs airway epithelial cell migration. The addition of corticosteroids after injury does not slow migration, despite their ability to induce apoptosis in these cells.

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ErbB2 activity is required for airway epithelial repair following neutrophil elastase exposure

The FASEB Journal ◽

10.1096/fj.04-2675fje ◽

2005 ◽

Vol 19 (10) ◽

pp. 1374-1376 ◽

Cited By ~ 9

Author(s):

Bernard M. Fischer ◽

Jacob G. Cuellar ◽

Angela S. Byrd ◽

Annette B. Rice ◽

James C. Bonner ◽

...

Keyword(s):

Neutrophil Elastase ◽

Airway Epithelial ◽

Epithelial Repair

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Hog barn dust slows airway epithelial cell migration in vitro through a PKCα-dependent mechanism

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00274.2007 ◽

2007 ◽

Vol 293 (6) ◽

pp. L1469-L1474 ◽

Cited By ~ 22

Author(s):

Rebecca E. Slager ◽

Diane S. Allen-Gipson ◽

Alexi Sammut ◽

Art Heires ◽

Jane DeVasure ◽

...

Keyword(s):

Cell Migration ◽

Epithelial Cell ◽

Cell Lines ◽

Wound Closure ◽

Airway Remodeling ◽

Occupational Exposures ◽

Dust Exposure ◽

Airway Epithelial ◽

Airway Injury ◽

Pkc Isoforms

Agricultural work and other occupational exposures are responsible for ∼15% of chronic obstructive pulmonary disease (COPD). COPD involves airway remodeling in response to chronic lung inflammatory events and altered airway repair mechanisms. However, the effect of agricultural dust exposure on signaling pathways that regulate airway injury and repair has not been well characterized. A key step in this process is migration of airway cells to restore epithelial integrity. We have previously shown that agents that activate the critical regulatory enzyme protein kinase C (PKC) slow cell migration during wound repair. Based on this observation and direct kinase measurements that demonstrate that dust extract from hog confinement barns (HDE) specifically activates the PKC isoforms PKCα and PKCε, we hypothesized that HDE would slow wound closure time in airway epithelial cells. We utilized the human bronchial epithelial cell line BEAS-2B and transfected BEAS-2B cell lines that express dominant negative (DN) forms of PKC isoforms to demonstrate that HDE slows wound closure in BEAS-2B and PKCε DN cell lines. However, in PKCα DN cells, wound closure following HDE treatment is not significantly different than media-treated cells. These results suggest that the PKCα isoform is an important regulator of cell migration in response to agricultural dust exposure.

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