Response of Human Embryonic Stem Cell–Derived Mesenchymal Stem Cells to Osteogenic Factors and Architectures of Materials During In Vitro Osteogenesis

Abstract

One of the major challenges to the application of human embryonic stem cells (hESCs) to the repair of defective tissues is the directed differentiation of cells into specific lineages to avoid the formation of inferior heterogeneous tissues. To accomplish this goal, the lineage-specific stem cell population needs to be isolated and optimal differentiation conditions need to be defined. In this study, homogenous hESC-derived mesenchymal stem cells (hESC-MSCs) were generated and used to construct bone tissue. The effect of osteogenic factors, including dexamethasone (Dex) and bone morphogenetic protein-7 (BMP-7), on the osteogenesis of hESC-MSCs was investigated. It was found that BMP-7 itself had little effect on the in vitro osteogenic differentiation of hESC-MSCs; however, there was a synergic effect between BMP-7 and Dex in promoting osteogenesis. The effect of osteoconductive nanofibrous polylactic acid material on osteogenesis of hESC-MSCs was also investigated. It was found that the nanofibrous matrix architecture promoted alkaline phosphatase activity and calcium deposition of cells cultured under osteogenic conditions. Based on these findings, the hESC-MSCs were cultured on three-dimensional nanofibrous scaffolds in combination with Dex and BMP-7 stimulation in vitro to generate bone-like tissues. After 6 weeks of culture, highly mineralized tissues developed with specific bone marker genes expressed. These data illustrate the promise of hESC-MSCs for bone regeneration under optimal conditions.