Abstract 17737: Rigid Two-Dimensional Microenvironments Promote Cardiac Differentiation
Introduction: While adult heart muscle is the least regenerative of tissues, embryonic cardiomyocytes are known to be proliferative, with ES cells providing an endless reservoir. Though previous studies have shown that matrix elasticity can influence cardiac phenotype in neonatal cardiomyocytes, precisely how these factors affect the lineage specification of cardiac progenitor cells from the pluripotent state is poorly understood. Hypothesis: We assessed whether in vitro cardiac differentiation of murine ES cells shows sensitivity to the substrate-level elasticity of the 2D matrix.
Methods: Both wild type and Nkx2.5-neoR embryoid bodies were differentiated on substrates of varied elastic modulus: standard rigid tissue culture (TC) plate, and progressively softer polydimethylsiloxane (PDMS) substrates of 10:1 and 50:1 base-to-crosslinker ratio.
Results: Rigid extracellular matrices promote a higher yield of de novo cardiomyocytes from two-dimensional culture, as assessed by the number of cardiac troponin T (cTnT) positive cells (Fig. A). Using an Nkx2.5-neomycin selection system, we also demonstrate this effect in a more purified cardiac population that shows greater cTnT expression, beating rate of foci, and expression ratio of adult α-MHC to fetal β-MHC mRNA (Fig. B). Furthermore, mechanical interferometry imaging demonstrates that these ES-derived cardiomyocytes display functional maturity and synchronization of beating when co-cultured with neonatal cardiomyocytes (Fig. C).
Conclusions: Collectively, these findings can help direct the production of functional cardiomyocytes en masse for regenerative medicine purposes. .
- © 2012 by American Heart Association, Inc.