Coculture of mesenchymal stem cells and respiratory epithelial cells to engineer a human composite respiratory mucosa

In this study, we describe a novel in vitro reconstitution system for tracheal epithelium that could be useful for investigating the cellular and molecular interaction of epithelial and mesenchymal cells. In this system, a Transwell insert was used as a basement membrane on which adult bone marrow mesenchymal stem cells (MSCs) were cultured on the lower side whereas normal human bronchial epithelial (NHBE) cells were cultured on the opposite upper side. Under air-liquid interface conditions, the epithelial cells maintained their capacity to progressively differentiate and form a functional epithelium, leading to the differentiation of mucin-producing cells between days 14 and 21. Analysis of apical secretions showed that mucin production increased over time, with peak secretion on day 21 for NHBE cells alone, whereas mucin secretion by NHBE cells cocultured with MSCs remained constant between days 18 and day 25. This in vitro model of respiratory epithelium, which exhibited morphologic, histologic, and functional features of a tracheal mucosa, could help to understand interactions between mesenchymal and epithelial cells and mechanisms involved in mucus production, inflammation, and airway repair. It might also play an important role in the design of an composite prosthesis for tracheal replacement.