Increased T-cell survival by structural bronchial cells derived from asthmatic subjects cultured in an engineered human mucosa

BackgroundInteraction between lymphocytes and structural cells has been proposed as a key factor in regulating inflammation in asthma.ObjectiveThis study was designed to investigate the effect of epithelial cells and fibroblasts on T-lymphocyte survival by using a 3-dimensional tissue-engineered model.MethodsEngineered human bronchial mucosal tissues were produced by using fibroblasts, epithelial cells, and autologous T cells from asthmatic and healthy donors. T-cell apoptosis and apoptotic marker expression by T cells were evaluated by using the terminal deoxynucleotidyl transferase biotinylated d-UTP nick end-labeling technique and immunofluorescence, respectively. Cytokines implicated in T-cell survival were measured by means of ELISA in culture supernatants.ResultsWe demonstrated histologically that we were able to generate a well-structured engineered bronchial mucosa by using epithelial cells, fibroblasts, and T cells cultured from healthy and asthmatic subjects. Structural cells from asthmatic subjects cultured in this model induced a significant decrease in the ability of T cells to undergo apoptosis represented by a decrease in DNA fragmentation and proapoptotic molecule expression (Bcl-2–associated X protein and Fas ligand). Structural cells from healthy control subjects have no effect. Among cytokines measured in the supernatants, only TGF-β1 was significantly increased in the model derived from cells of asthmatic subjects.ConclusionThese results support the concept that bronchial structural cells might play a critical role in the regulation of inflammation in asthma by increasing the survival of T lymphocytes. The results also further validated the model as a tool for investigating the interaction between inflammatory and structural cells.