Related Experiment Videos
Ferret tracheal epithelial cells grown in vitro are resistant to lethal injury by activated neutrophils
Y Chung1, C M Kercsmar, P B Davis
1Department of Pediatrics, Case Western Reserve University School of Medicine, Rainbow Babies and Children's Hospital, Cleveland, Ohio 44106.
Abstract:
Airway inflammation is often accompanied by accumulation of polymorphonuclear leukocytes (PMN) as well as epithelial sloughing. To determine whether PMN contribute to epithelial damage in inflammatory states, we examined the interaction of PMN and tracheal epithelial cells in culture. Ferret tracheal epithelial (FTE) cells were grown in primary culture on collagen-coated multiwell dishes. Confluent monolayers were loaded with [51Cr]O4 and exposed to resting and activated neutrophils. There was no significant increase in cell death as assessed by [51Cr]O4 release over 8 h of exposure, at effector (PMN)-to-target cell (epithelial cell) ratios up to 90:1, whether PMN were activated by maximal activating concentrations of phorbol myristate acetate or formylmethionylleucylphenylalanine with or without cytochalasin B. This result was confirmed by using a [3H]leucine release assay as well as by uptake of a supravital dye. However, exposure of FTE cells to activated PMN for 4 h resulted in separation of adjacent cells and formation of gaps in the monolayer, without significant detachment of epithelial cells from the dish. Gap formation was prevented by alpha 1-antitrypsin, N-methoxysuccinyl-Ala-Ala-Pro-Val-chloromethylketone, or 10% serum, was mimicked by PMN elastase (24 micrograms/ml), but not by hydrogen peroxide in concentrations up to 10 mM, or superoxide generated by xanthine/xanthine oxidase, and was reversible within 24 h of removal of elastase and exposure to fresh medium. We conclude that activated PMN do not kill FTE cells in culture. However, disruption of the epithelial cell monolayer probably by a proteolytic mechanism can result from exposure to activated PMN and may allow alteration of the epithelial barrier during airway inflammation.
Insights
Activated neutrophils do not kill airway epithelial cells but can disrupt cell layers. This disruption, likely due to proteolysis, may alter the epithelial barrier during airway inflammation.
Area of Science:
- Respiratory Medicine
- Cell Biology
- Immunology
Background:
- Airway inflammation involves polymorphonuclear leukocytes (PMN) and epithelial cell damage.
- The role of PMN in causing epithelial damage during inflammation requires clarification.
Purpose of the Study:
- To investigate the interaction between PMN and tracheal epithelial cells (FTE) in vitro.
- To determine if PMN contribute to epithelial damage and barrier disruption.
Main Methods:
- Primary culture of Ferret tracheal epithelial (FTE) cells.
- Exposure of confluent FTE monolayers to resting and activated human neutrophils.
- Assessment of cell death using 51Cr release, 3H-leucine release, and supravital dye uptake.
- Evaluation of monolayer integrity through gap formation and cell separation.
Main Results:
- Activated PMN did not cause significant cell death in FTE cultures up to 8 hours.
- Exposure to activated PMN induced separation of adjacent FTE cells and gap formation in monolayers.
- Gap formation was inhibited by alpha 1-antitrypsin, a protease inhibitor, and PMN elastase mimicked the effect.
- The disruption was reversible and not caused by hydrogen peroxide or superoxide.
Conclusions:
- Activated PMN do not directly kill tracheal epithelial cells in culture.
- PMN-induced disruption of the epithelial monolayer, likely via proteolysis, can occur.
- This disruption may contribute to altered epithelial barrier function during airway inflammation.