Engineered extracellular microenvironment with a tunable mechanical property for controlling cell behavior and cardiomyogenic fate of cardiac stem cells

摘要

Endogenous cardiac stem cells (CSCs) are known to play a certain role in the myocardial homeostasis of the adult heart. The extracellular matrix (ECM) surrounding CSCs provides mechanical signals to regulate a variety of cell behaviors, yet the impact in the adult heart of these mechanical properties of ECM on CSC renewal and fate decisions is mostly unknown. To elucidate CSC mechanoresponses at the individual cell and myocardial level, we used the sol-to-gel transitional gelatin-poly(ethylene glycol)-tyramine (GPT) hydrogel with a tunable mechanical property to construct a three-dimensional (3D) matrix for culturing native myocardium and CSCs. The elastic modulus of the GPT hydrogel was controlled by adjusting cross-linking density using hydrogen peroxide. The GPT hydrogel showed an ability to transduce integrin-mediated signals into the myocardium and to permit myocardial homeostatic processes in vitro, including CSC migration and proliferation into the hydrogel from the myocardium. Decreasing the elastic modulus of the hydrogel resulted in upregulation of phosphorylated integrin-mediated signaling molecules in CSCs, which were associated with significant increases in cell spreading, migration, and proliferation of CSCs in a modulus-dependent manner. However, increasing the elastic modulus of hydro gel induced the arrest of cell growth but led to upregulation of cardiomyocyte-associated mRNAs in CSCs. This work demonstrates that tunable 3D-engineered microenvironments created by GPT hydrogel are able to control CSC behavior and to direct cardiomyogenic fate. Our system may also be appropriate for studying the mechanoresponse of CSCs in a 3D context as well as for developing therapeutic strategies for in situ myocardial regeneration.