The tight junction protein ZO-1 is dispensable for barrier function but critical for effective mucosal repair

Abstract Background: While exposure to diesel exhaust particles has been linked to aberrant immune responses in allergic diseases such as asthma, little attention has been paid to their effects on the airway epithelium. In this study, we sought to determine the effect of diesel exhaust exposure on airway epithelial barrier function and composition using in vitro and in vivo model systems. Methods: 16HBE14o- human bronchial epithelial cells were grown on collagen coated Transwell inserts and exposed to 5 to 50 µg/cm2 SRM 2975 diesel particulate matter (DEP) suspended in cell culture medium or vehicle controls. Changes in barrier function were assessed by measuring transepithelial electrical resistance (TEER) and permeability to 4 kDa FITC Dextran. Neonatal BALB/c mice were exposed to aerosolized DEP (255 ± 89 µg/m3; 2 hours per day for 5 days) and changes in the tight junction protein Tricellulin were assessed two weeks post exposure. Results: A six-hour incubation of epithelial cells with diesel exhaust particles caused a significant concentration-dependent reduction in epithelial barrier integrity as measured by decreased TEER and increased permeability to 4 kDa FITC-Dextran. This reduction in epithelial barrier integrity corresponded to a significant reduction in expression of the tight junction protein Tricellulin. siRNA mediated knockdown of Tricellulin recapitulated changes in barrier function caused by DEP exposure. Neonatal exposure to aerosolized DEP caused a significant reduction in lung Tricellulin two weeks post exposure at both the protein and mRNA level. Conclusion: Short term exposure to DEP causes a significant reduction in epithelial barrier integrity through a reduction in the tight junction protein Tricellulin. Neonatal exposure to aerosolized DEP caused a significant and sustained reduction in Tricellulin protein and mRNA in the lung, suggesting that early life exposure to inhaled DEP may cause lasting changes in airway epithelial barrier function.

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Diesel Exhaust Particle Exposure Reduces Expression of the Epithelial Tight Junction Protein Tricellulin

10.21203/rs.3.rs-25522/v1 ◽

2020 ◽

Author(s):

Timothy Smyth ◽

Janelle Veazey ◽

Sophia Eliseeva ◽

David Chalupa ◽

Alison Elder ◽

...

Keyword(s):

Tight Junction ◽

Diesel Exhaust ◽

Barrier Function ◽

Diesel Exhaust Particles ◽

Tight Junction Protein ◽

Epithelial Barrier ◽

Airway Epithelial ◽

Epithelial Barrier Function ◽

Barrier Integrity ◽

Junction Protein

Abstract Background While exposure to diesel exhaust particles has been linked to aberrant immune responses in allergic diseases such as asthma, little attention has been payed to their effects on the airway epithelium. In this study, we sought to determine the effect of diesel exhaust exposure on airway epithelial barrier function and composition using in vitro and in vivo model systems. 16HBE14o- human bronchial epithelial cells were grown on collagen coated Transwell inserts and exposed to 5 to 50 µg/cm2 SRM 2975 diesel particulate matter (DEP) suspended in cell culture medium or vehicle controls. Changes in barrier function were assessed by measuring transepithelial electrical resistance (TEER) and permeability to 4 kDa FITC Dextran. Neonatal BALB/c mice were exposed to aerosolized DEP (255 ± 89 µg/m3; 2 hours per day for 5 days) and changes in the tight junction protein Tricellulin were assessed two weeks post exposure. Results A six-hour incubation of epithelial cells with diesel exhaust particles caused a significant concentration-dependent reduction in epithelial barrier integrity as measured by decreased TEER and increased permeability to 4 kDa FITC-Dextran. This reduction in epithelial barrier integrity corresponded to a significant reduction in expression of the tight junction protein Tricellulin. siRNA mediated knockdown of Tricellulin recapitulated changes in barrier function caused by DEP exposure. Neonatal exposure to aerosolized DEP caused a significant reduction in lung Tricellulin two weeks post exposure at both the protein and mRNA level. Conclusion Short term exposure to DEP causes a significant reduction in epithelial barrier integrity through a reduction in the tight junction protein Tricellulin. Neonatal exposure to aerosolized DEP caused a significant and sustained reduction in Tricellulin protein and mRNA in the lung, suggesting that early life exposure to inhaled DEP may cause lasting changes in airway epithelial barrier function.

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Diesel exhaust particle exposure reduces expression of the epithelial tight junction protein Tricellulin

Particle and Fibre Toxicology ◽

10.1186/s12989-020-00383-x ◽

2020 ◽

Vol 17 (1) ◽

Author(s):

Timothy Smyth ◽

Janelle Veazey ◽

Sophia Eliseeva ◽

David Chalupa ◽

Alison Elder ◽

...

Keyword(s):

Tight Junction ◽

Diesel Exhaust ◽

Barrier Function ◽

Diesel Exhaust Particles ◽

Tight Junction Protein ◽

Epithelial Barrier ◽

Airway Epithelial ◽

Epithelial Barrier Function ◽

Barrier Integrity ◽

Junction Protein

Abstract Background While exposure to diesel exhaust particles has been linked to aberrant immune responses in allergic diseases such as asthma, little attention has been paid to their effects on the airway epithelial barrier. In this study, we sought to determine the effect of diesel exhaust exposure on airway epithelial barrier function and composition using in vitro and in vivo model systems. Methods 16HBE14o- human bronchial epithelial cells were grown on collagen coated Transwell inserts and exposed to 5 to 50 μg/cm2 SRM 2975 diesel particulate matter (DEP) suspended in cell culture medium or vehicle controls. Changes in barrier function were assessed by measuring transepithelial electrical resistance (TEER) and permeability to 4 kDa FITC Dextran. Neonatal BALB/c mice were exposed to aerosolized DEP (255 ± 89 μg/m3; 2 h per day for 5 days) and changes in the tight junction protein Tricellulin were assessed 2 weeks post exposure. Results A six-hour incubation of epithelial cells with diesel exhaust particles caused a significant concentration-dependent reduction in epithelial barrier integrity as measured by decreased TEER and increased permeability to 4 kDa FITC-Dextran. This reduction in epithelial barrier integrity corresponded to a significant reduction in expression of the tight junction protein Tricellulin. siRNA mediated knockdown of Tricellulin recapitulated changes in barrier function caused by DEP exposure. Neonatal exposure to aerosolized DEP caused a significant reduction in lung Tricellulin 2 weeks post exposure at both the protein and mRNA level. Conclusion Short term exposure to DEP causes a significant reduction in epithelial barrier integrity through a reduction in the tight junction protein Tricellulin. Neonatal exposure to aerosolized DEP caused a significant and sustained reduction in Tricellulin protein and mRNA in the lung, suggesting that early life exposure to inhaled DEP may cause lasting changes in airway epithelial barrier function.

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Diets high in fermentable protein and fibre alter tight junction protein composition with minor effects on barrier function in piglet colon

British Journal Of Nutrition ◽

10.1017/s0007114513003498 ◽

2013 ◽

Vol 111 (6) ◽

pp. 1040-1049 ◽

Cited By ~ 23

Author(s):

Jan F. Richter ◽

Robert Pieper ◽

Silke S. Zakrzewski ◽

Dorothee Günzel ◽

Joerg D. Schulzke ◽

...

Keyword(s):

Tight Junction ◽

Ion Transport ◽

Barrier Function ◽

Crude Protein ◽

Short Circuit ◽

Protein Composition ◽

Tight Junction Protein ◽

Interactive Effects ◽

Na Channel ◽

Junction Protein

Protein fermentation end products may damage the colonic mucosa, which could be counteracted by dietary inclusion of fermentable carbohydrates (fCHO). Although fermentable crude protein (fCP) and fCHO are known to affect microbial ecology, their interactive effects on epithelial barrier function are unknown. In the present study, in a 2 × 2 factorial experiment, thirty-two weaned piglets were fed low-fCP/low-fCHO (14·5 % crude protein (CP)/14·5 % total dietary fibre (TDF)), low-fCP/high-fCHO (14·8 % CP/16·6 % TDF), high-fCP/low-fCHO (19·8 % CP/14·5 % TDF) and high-fCP/high-fCHO (20·1 % CP/18·0 % TDF) diets. After 21–23 d, samples of proximal and distal colonic mucosae were investigated in Ussing chambers with respect to the paracellular and transcytotic passages of macromolecules and epithelial ion transport. The high-fCHO diets were found to reduce the permeability of the distal colon to the transcytotic marker horseradish peroxidase (HRP, 44 kDa; P <0·05) and also reduce the paracellular permeation of N-hydroxysuccinimide-biotin into the submucosa (443 Da; P <0·05), whereas that of HRP was decreased by the high-fCP diets (P <0·01). Short-circuit current (active ion transport), transepithelial resistance (barrier function) and charge selectivity were largely unaffected in both the segments. However, the high-fCP diets were found to suppress the aldosterone-induced epithelial Na channel activity (P <0·01) irrespective of fCHO inclusion. The high-fCP diets generally reduced the expression of colonic claudin-1, claudin-2 and claudin-3 (P <0·01), while that of claudin-4 was increased by the high-fCHO diets (P <0·01). The high-fCHO diets also altered the ratio between occludin forms (P <0·05) and increased the expression of tricellulin in the proximal colon, which was not observed with high-fCP diets. In conclusion, dietary fCHO and fCP exerted few and largely independent effects on functional measurements, but altered tight junction protein composition in a compensatory way, so that colonic transport and barrier properties were only marginally affected.

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Sa1760 Influence of Bovine Colostrum on Tight Junction Protein Expression, Barrier Function and Intestinal Cytokine Milieu

Gastroenterology ◽

10.1016/s0016-5085(13)61072-0 ◽

2013 ◽

Vol 144 (5) ◽

pp. S-300

Author(s):

Peggy Bodammer ◽

Claudia Maletzki ◽

Claus Kerkhoff ◽

Georg Lamprecht

Keyword(s):

Protein Expression ◽

Tight Junction ◽

Barrier Function ◽

Bovine Colostrum ◽

Tight Junction Protein ◽

Tight Junction Protein Expression ◽

Junction Protein ◽

Cytokine Milieu

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Occludin S408 phosphorylation regulates tight junction protein interactions and barrier function

The Journal of Cell Biology ◽

10.1083/jcb.201010065 ◽

2011 ◽

Vol 193 (3) ◽

pp. 565-582 ◽

Cited By ~ 154

Author(s):

David R. Raleigh ◽

Devin M. Boe ◽

Dan Yu ◽

Christopher R. Weber ◽

Amanda M. Marchiando ◽

...

Keyword(s):

Tight Junction ◽

Dynamic Behavior ◽

Protein Interactions ◽

Protein Complex ◽

Barrier Function ◽

Therapeutic Potential ◽

Paracellular Permeability ◽

Tight Junction Protein ◽

Barrier Dysfunction ◽

Junction Protein

Although the C-terminal cytoplasmic tail of the tight junction protein occludin is heavily phosphorylated, the functional impact of most individual sites is undefined. Here, we show that inhibition of CK2-mediated occludin S408 phosphorylation elevates transepithelial resistance by reducing paracellular cation flux. This regulation requires occludin, claudin-1, claudin-2, and ZO-1. S408 dephosphorylation reduces occludin exchange, but increases exchange of ZO-1, claudin-1, and claudin-2, thereby causing the mobile fractions of these proteins to converge. Claudin-4 exchange is not affected. ZO-1 domains that mediate interactions with occludin and claudins are required for increases in claudin-2 exchange, suggesting assembly of a phosphorylation-sensitive protein complex. Consistent with this, binding of claudin-1 and claudin-2, but not claudin-4, to S408A occludin tail is increased relative to S408D. Finally, CK2 inhibition reversed IL-13–induced, claudin-2–dependent barrier loss. Thus, occludin S408 dephosphorylation regulates paracellular permeability by remodeling tight junction protein dynamic behavior and intermolecular interactions between occludin, ZO-1, and select claudins, and may have therapeutic potential in inflammation-associated barrier dysfunction.

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