Intercellular interactions in the cell microenvironment play a critical role in determining cell fate, but the effects of these interactions on pathways governing human embryonic stem cell (hESC) behavior have not been fully elucidated. We and others have previously reported that 3-D culture of hESCs affects cell fates, including self-renewal and differentiation to a variety of lineages. Here we have used a microwell culture system that produces 3-D colonies of uniform size and shape to provide insight into the effect of modulating cell-cell contact on canonical Wnt/β-catenin signaling in hESCs. Canonical Wnt signaling has been implicated in both self-renewal and differentiation of hESCs, and competition for β-catenin between the Wnt pathway and cadherin-mediated cell-cell interactions impacts various developmental processes, including the epithelial-mesenchymal transition. Our results showed that hESCs cultured in 3-D microwells exhibited higher E-cadherin expression than cells on 2-D substrates. The increase in E-cadherin expression in microwells was accompanied by a downregulation of Wnt signaling, as evidenced by the lack of nuclear β-catenin and downregulation of Wnt target genes. Despite this reduction in Wnt signaling in microwell cultures, embryoid bodies (EBs) formed from hESCs cultured in microwells exhibited higher levels of Wnt signaling than EBs from hESCs cultured on 2-D substrates. Furthermore, the Wnt-positive cells within EBs showed upregulation of genes associated with cardiogenesis. These results demonstrate that modulation of intercellular interactions impacts Wnt/β-catenin signaling in hESCs.
|Original language||English (US)|
|Number of pages||9|
|State||Published - Mar 2012|
Bibliographical noteFunding Information:
This study was supported by NIH/NIBIB R01 EB007534 (SPP), NSF EFRI-0735903 (SPP), the UW-Madison Materials Research Science and Engineering Center (MRSEC), and an NSF graduate research fellowship (SMA). The authors would like to thank the WiCell Research Institute for providing cells and reagents, the staff at the University of Wisconsin Comprehensive Cancer Center Flow Cytometry Facility for assistance with flow cytometry and cell sorting, and the W.M. Keck Laboratory for Biological Imaging for support with confocal microscopy.
Copyright 2012 Elsevier B.V., All rights reserved.
- Cell adhesion
- Cell signaling
- Stem cell