Novel approach to enhance aggregate migration-driven epigenetic memory which induces cardiomyogenic differentiation...

The dynamic migratory behavior of human mesenchymal stem cells (hMSCs) has a significant impact on the epigenetic profiles that determine fate choice and lineage commitment during differentiation. Here we report a novel approach to enhance repeated migration-driven epigenetic memory which induces cardiomyogenic differentiation on a dendrimer surface with fifth generation (G5). Cells exhibited the formation of cell aggregates on the G5 surface through active migration with morphological changes, and these aggregates showed strong expression of the cardiac-specific marker cardiac troponin T (cTnT) at 10 days. When cell aggregates were passaged onto a fresh G5 surface over three passages of 40 days, the expression levels of the multiple cardiac-specific markers including GATA4, NKX2.5, MYH7, and TNNT2 were higher compared to those passaged as single cells. To investigate whether cardiomyogenic differentiation of hMSCs was enhanced by repeated aggregate migration-driven epigenetic memory, cells on the G5 surface were reseeded onto a fresh G5 surface during three passages using aggregate-based and single cell-based passage methods. Analyses of global changes in H3 histone modifications exhibited pattern of increased H3K9ac and H3K27me3, and decreased H3K9me3 in aggregate-based passage cultures during three passages. However, the pattern of their histone modification on the PS surface was repeated after the initialization and reformation during three passages in single cell-based passage cultures. Thus, repetitive aggregate migratory behavior during aggregate-based passage led to a greater degree of histone modification, as well as gene expression changes suggestive of cardiomyogenic differentiation.