Differential Effects of Acellular Embryonic Matrices on Pluripotent Stem Cell Expansion and Neural Differentiation

Extracellular matrices (ECM) derived from pluripotent stem cells (PSCs) provide unique niche that can direct cellular differentiation and tissue regeneration as well as rejuvenation of aged progenitor cells.  Decellularized ECMs have also been used as bioink for bioprinting of cell-laden constructs.  The unlimited growth capacity of PSCs allows the scalable generation of the associated ECMs which can be used for biomanufacturing.  Therefore, derivation and characterization of PSC-derived ECMs are critical for the applications in drug screening, disease modeling and regenerative medicine.  In this study, 3-D ECMs of undifferentiated embryonic stem cell (ESC) aggregates (AGG), spontaneously differentiated embryoid bodies (EB), and ESC-derived neural progenitor cell (NPC) aggregates were decellularized and their capacities to direct proliferation and neural differentiation of the reseeded mouse ESCs and human induced pluripotent stem cells (iPSCs) were characterized.  Proteomic analysis by liquid chromatography–tandem mass spectrometry (LC-MS/MS) revealed protein expression profiles that reflected distinct niche properties for each tested ECM group.  The reseeded mouse ESCs and human iPSCs responded to different types of ECMs with high expression of pluripotent markers (Oct-4 and Nanog) for the cells grown on the AGG-ECM and the accelerated neural differentiation (expressions of β-tubulin III and Nestin) for the cells grown on the NPC-ECM.  The role of Wnt/β-catenin signaling in the cell-matrix interactions was also studied and the expression of β-catenin was reduced in the cells grown on the NPC-ECM.  This study demonstrates that PSC-derived ECMs are able to influence stem cell proliferation and differentiation by providing a spectrum of stem cell niche microenvironments during embryonic tissue development.