Enhanced reseeding of decellularized rodent lungs with mouse embryonic stem cells

Repopulation of decellularized lung scaffolds (DLS) is limited due to alterations in the repertoire and ratios of the residual extracellular matrix (ECM) proteins, characterized by e.g., the retention of type I collagen and loss of glycoproteins. We hypothesized that pre-treatment of decellularized matrices with defined ECM proteins, which match the repertoire of integrin receptors expressed by the cells to be seeded (e.g., embryonic stem cells) can increase the efficacy of the reseeding process. To test this hypothesis, we first determined the integrin receptors profile of mouse embryonic stem cells (mESCs). Mouse ESCs express alpha 3, alpha 5, alpha 6, alpha 9 and beta 1, but not alpha 1, alpha 2 and alpha 4 integrin subunits, as established by Western blotting and adhesion to laminin and fibronectin, but not to collagens type I and IV. Reseeding of DLS with mESCs was inefficient (6.9 +/- 0.5%), but was significantly enhanced (2.3 +/- 0.1 fold) by pretreating the scaffolds with media conditioned by A549 human lung adenocarcinoma cells, which we found to contain similar to 5 mu g/ml laminin. Furthermore, pre-treatment with A549-conditioned media resulted in a significantly more uniform distribution of the seeded mESCs throughout the engineered organ as compared to untreated DLS. Our study may advance whole lung engineering by stressing the importance of matching the integrin receptor repertoire of the seeded cells and the cell binding motifs of DLS. (C) 2013 Elsevier Ltd. All rights reserved.