Assessment of biological responses of EpiAirway 3-D cell constructs versus A549 cells for determining toxicity of ambient air pollution.
BACKGROUND
EpiAirway™ 3-D constructs are human-derived cell cultures of differentiated airway epithelial cells that may represent a more biologically relevant model of the human lung. However, limited information is available on their utility for exposures to air pollutants at the air-liquid interface (ALI).


OBJECTIVE
To assess the biological responses of EpiAirway™ cells in comparison to the responses of A549 human alveolar epithelial cells after exposure to air pollutants at ALI.


METHODS
Cells were exposed to filtered air, 400 ppb of ozone (O3) or a photochemically aged Synthetic Urban Mixture (SynUrb54) consisting of hydrocarbons, nitrogen oxides, O3 and other secondary oxidation products for 4 h. Basolateral supernatants and apical washes were collected at 9 and 24 h post-exposure. We assessed cytotoxicity by measuring lactate dehydrogenase (LDH) release into the culture medium and apical surface. Interleukin 6 (IL-6) and interleukin 8 (IL-8) proteins were measured in the culture medium and in the apical washes to determine the inflammatory response after exposure.


RESULTS
Both O3 and SynUrb54 significantly increased basolateral levels of LDH and IL-8 in A549 cells. No significant changes in LDH and IL-8 levels were observed in the EpiAirway™ cells, however, IL-6 in the apical surface was significantly elevated at 24 h after O3 exposure.


CONCLUSIONS
LDH and IL-8 are robust endpoints for assessing toxicity in A549 cells. The EpiAirway™ cells show minimal adverse effects after exposure suggesting that they are more toxicologically resistant compared to A549 cells. Higher concentrations or longer exposure times are needed to induce effects on EpiAirway™ cells.
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .
Jose
J
Zavala
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .
Bridget
B
O'Brien
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .
Kim
K
Lichtveld
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .
Kenneth G
KG
Sexton
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .
Ivan
I
Rusyn
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .|b Department of Pediatrics , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA , and.|c Center for Environmental Medicine and Lung Biology, University of North Carolina at Chapel Hill , Chapel Hill , NC, USA.
Ilona
I
Jaspers
a Department of Environmental Sciences & Engineering , University of North Carolina at Chapel Hill , Chapel Hill , NC, USA .
William
W
Vizuete
D000393:Air Pollutants / Q000633:toxicity*; D015415:Biomarkers / Q000378:metabolism; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006838:Hydrocarbons / Q000633:toxicity*; D019570:Inhalation Exposure / Q000009:adverse effects; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009589:Nitrogen Oxides / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D018570:Risk Assessment; D013997:Time Factors
D000393:Air Pollutants; D015415:Biomarkers; C508606:CXCL8 protein, human; D006838:Hydrocarbons; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D009589:Nitrogen Oxides; D010126:Ozone; D007770:L-Lactate Dehydrogenase
A549, air–liquid interface; EpiAirway; GIVES; in vitro; inhalation; ozone; synthetic urban mixture