Kraehenbuehl, T. P.Zammaretti, P.Van der Vlies, A. J.Schoenmakers, R. G.Lutolf, M. P.Jaconi, M. E.Hubbell, J. A.2008-05-262008-05-262008-05-26200810.1016/j.biomaterials.2008.03.016https://infoscience.epfl.ch/handle/20.500.14299/25920WOS:000256144300007We show that synthetic three-dimensional (3D) matrix metalloproteinase (MMP)-sensitive poly(ethylene glycol) (PEG)-based hydrogels can direct differentiation of pluripotent cardioprogenitors, using P19 embryonal carcinoma (EC) cells as a model, along a cardiac lineage in vitro. In order to systematically probe 3D matrix effects on P19 EC differentiation, matrix elasticity, MMP-sensitivity and the concentration of a matrix-bound RGDSP peptide were modulated. Soft matrices (E=322+/-64.2Pa, stoichiometric ratio: 0.8), mimicking the elasticity of embryonic cardiac tissue, increased the fraction of cells expressing the early cardiac transcription factor Nkx2.5 around 2-fold compared to embryoid bodies (EB) in suspension. In contrast, stiffer matrices (E=4036+/-419.6Pa, stoichiometric ratio: 1.2) decreased the number of Nkx2.5-positive cells significantly. Further indicators of cardiac maturation were promoted by ligation of integrins relevant in early cardiac development (alpha(5)beta(1,) alpha(v)beta(3)) by the RGDSP ligand in combination with the MMP-sensitivity of the matrix, with a 6-fold increased amount of myosin heavy chain (MHC)-positive cells as compared to EB in suspension. This precisely controlled 3D culture system thus may serve as a potential alternative to natural matrices for engineering cardiac tissue structures for cell culture and potentially therapeutic applications.text::journal::journal article::research article