Long-Term Culture of Distal Airway Epithelial Cells Allows Differentiation Towards Alveolar Epithelial Cells Suited for Influenza Virus Studies

Imai-Matsushima, Aki; Martin-Sancho, Laura; Karlas, Alexander; Imai, Seiichiro; Zoranovic, Tamara; Hocke, Andreas C.; Mollenkopf, Hans-Joachim; Berger, Hilmar; Meyer, Thomas F.

We also adapted the new model to avian DAECsan important host species for zoonotic viruses affecting the lungs. Here, we achieved efficient long-term growth of chicken DAECs and differentiation towards cells positive for SFTPA and AQP5, molecular markers of chicken pneumocytes. The localization of these molecular markers in vivo strongly suggests that they are epithelial cells of the parabronchi, the site of gas exchange in birds [52, 53] . In contrast to human DAECs, chicken DAECs required the TGF-β receptor kinase inhibitor RepSox, not the Notch inhibitor DBZ to maintain proliferation, which closely resembles the signalling pathways activated in mammalian airway epithelial cells in vitro [54] [55] [56] . In addition, SFTPA and AQP5 were expressed regardless of induction treatment and remained relatively stable after feeder removal. While different cell types corresponding to the mammalian type I and II alveolar epithelial cells have been reported in chicken, the relationship between them remains unknown.