Tissue engineering of lung: the effect of extracellular matrix on the differentiation of embryonic stem cells to pneumocytes.

We have previously differentiated lung epithelium from human and murine embryonic stem cells (mESCs) and are now exploring the potential applications of these cells, including in the engineering of lung tissue constructs. In this study, we hypothesized that the differentiation and maintenance of lung epithelium derived from mESCs can be enhanced by extracellular matrix (ECM) proteins. Our established differentiation protocol was applied to mESCs grown on a range of ECMs: collagen I, laminin 332, fibronectin, Matrigel, and, as an experimental control, gelatin. The ECMs were coated onto tissue culture plastic (TCP) and poly-DL-lactic acid (PDLLA), a biodegradable polymer we have previously shown to support the growth of mature pneumocytes. Matrigel or Laminin-332 coating of either TCP or PDLLA film resulted in enhanced surfactant protein C gene expression in differentiating mESCs, a direct indication of the upregulation of lung epithelial differentiation. For each combination, changes in the contact angle and zeta potential of protein-coated TCP and PDLLA film confirmed protein adsorption. We conclude that the choice of the coating protein can greatly affect the differentiation of ESCs, and laminin-332-coated PDLLA provided an ECM-degradable scaffold combination that is suitable for engineering of lung tissue constructs.