Engineering Embryonic Stem-Cell Aggregation Allows an Enhanced Osteogenic Differentiation In Vitro

Abstract

Pluripotent embryonic stem (ES) cells hold great promise for the field of tissue engineering, with numerous studies investigating differentiation into various cell types including cardiomyocytes, chondrocytes, and osteoblasts. Previous studies have detailed osteogenic differentiation via dissociated embryoid body (EB) culture in osteoinductive media comprising of ascorbic acid, beta-glycerophosphate, and dexamethasone. It is hoped that these osteogenic cultures will have clinical application in bone tissue repair and regeneration and pharmacological testing. However, differentiation remains highly inefficient and generates heterogeneous populations. We have previously reported an engineered three-dimensional culture system for controlled ES cell-ES cell interaction via the avidin-biotin binding complex. Here we investigate the effect of such engineering on ES cell differentiation. Engineered EBs exhibit enhanced osteogenic differentiation assessed by cadherin-11, Runx2, and osteopontin expression, alkaline phosphatase activity, and bone nodule formation. Results show that cultures produced from intact EBs aggregated for 3 days generated the greatest levels of osteogenic differentiation when cultured in osteoinductive media. However, when cultured in control media, only engineered samples appeared to exhibit bone nodule formation. In addition, polymerase chain reaction analysis revealed a decrease in endoderm and ectoderm expression within engineered samples. This suggests that engineered ES cell aggregation has increased mesoderm homogeneity, contributing to enhanced osteogenic differentiation.

Controlled embryoid body formation via surface modification and avidin–biotin cross-linking

“…A recent publication shows that the engineered culture system enhances osteogenic differentiation when using the set parameters described above (Gothard et al 2009). The hope now is that by altering and tweaking these parameters we could induce and control differentiation of multiple cell types.…”

Comparative Analysis of Mouse-Induced Pluripotent Stem Cells and Mesenchymal Stem Cells During Osteogenic Differentiation In Vitro

“…These observations are in accord with the macroscopic visual inspection of von Kossa staining, which showed studded mineralized areas in the iPSC cultures. Aggregation of ESCs increases mesodermal homogeneity, which enhances osteogenic differentiation in vitro [48]. In addition, altered internal mechanisms of iPSC aggregates may accelerate osteogenic differentiation, possibly by affecting compaction, condensation, and mechanical stress.…”

Tooth-derived stem cells: Update and perspectives

“…SCs can be isolated in the earliest stages of embryogenesis (embryonic SCs) [4][5][6][7][8][9] or in various postnatal tissues (adult SCs) [2,10,11] (Table 1). Although embryonic SCs present interesting properties, such as the ability to differentiate into hundreds of other cell types, the bioethical aspects involved in the study of these cells, especially for human embryos, have hindered advances in this field and research has thus been focused on adult SCs [1,[10][11][12] .…”