Open Access Methodology article

Newborn pig trachea cell line cultured in air-liquid interface conditions allows a partial in vitro representation of the porcine upper airway tissue

Mario Delgado-Ortega12, Michel Olivier12, Pierre-Yves Sizaret3, Gaëlle Simon45 and François Meurens6*

Author Affiliations

1 INRA, Infectiologie et Santé Publique, Nouzilly 37380, France

2 UMR1282 Infectiologie et Santé Publique, Université François Rabelais, Tours 37000, France

3 Département des microscopies, plate-forme R.I.O de microscopie électronique, Université François Rabelais, Tours 37000, France

4 Anses, Ploufragan/Plouzané Laboratory, Swine Virology Immunology Unit, Ploufragan BP 53, 22440, France

5 European University of Brittany, Rennes 35000, France

6 Vaccine and Infectious Disease Organization-InterVac, University of Saskatchewan, 120 Veterinary Road, Saskatoon S7N 5E3 Saskatchewan, Canada

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BMC Cell Biology 2014, 15:14  doi:10.1186/1471-2121-15-14

Published: 6 May 2014

Abstract

Background

The domestic pig is an excellent animal model to study human microbial diseases due to its similarity to humans in terms of anatomy, physiology, and genetics. We assessed the suitability of an in vitro air-liquid interface (ALI) culture system for newborn pig trachea (NPTr) cells as a practical tool for analyzing the immune response of respiratory epithelial cells to aggressors. This cell line offers a wide microbial susceptibility spectrum to both viruses and bacteria. The purpose of our study was to evaluate and characterize diverse aspects of cell differentiation using different culture media. After the NPTr cells reached confluence, the apical medium was removed and the cells were fed by medium from the basal side.

Results

We assessed the cellular layer’s capacity to polarize and differentiate in ALI conditions. Using immunofluorescence and electronic microscopy we evaluated the presence of goblet and ciliated cells, the epithelial junction organization, and the transepithelial electrical resistance. We found that the cellular layer develops a variable density of mucus producing cells and acquires a transepithelial resistance. We also identified increased development of cellular junctions over the culture period. Finally, we observed variable expression of transcripts associated to proteins such as keratin 8, mucins (MUC1, MUC2, and MUC4), occludin, and villin 1.

Conclusions

The culture of NPTr cells in ALI conditions allows a partial in vitro representation of porcine upper airway tissue that could be used to investigate some aspects of host/respiratory pathogen interactions.

Keywords:
Pig; Epithelial cell; Differentiation; Air-liquid interface; Trachea