Three-dimensional extracellular matrix stimulates gastrulation-like events in human embryoid bodies.
Human embryonic stem (hES) cells cultured in suspension form aggregates called embryoid bodies (EBs), which structurally resemble the pregastrulation-stage embryo. We show that these EBs express genes characteristic of the visceral endoderm (VE) and form an outer boundary of VE-like cells, but only a minority expresses markers of the primitive streak and the definitive endoderm in patterns suggestive of gastrulation-like events. EBs embedded in a Matrigel matrix, however, lack the presumptive VE but up-regulate expression of gastrulation-related genes, which is correlated with the expression of these genes in a greater proportion of individual EBs. Over time, Matrigelembedded EBs form internally organized structures and exhibit higher expression of markers of the definitive endoderm and mesoderm. We hypothesize that a three-dimensional adhesive support provides an organizing influence analogous to the early basal lamina surrounding the epiblast of the pregastrulation embryo. Furthermore, we identify a synthetic three-dimensional scaffold capable of supporting EB formation that partially mimics the effects of Matrigel.
Rust
William L
WL
ES Cell International Pte, Ltd., Singapore 138667. wrust@escellinternational.com
Sadasivam
Akila
A
Dunn
N Ray
NR
D001483:Base Sequence; D001709:Biotechnology / Q000379:methods / Q000639:trends; D018929:Cell Culture Techniques; D017931:DNA Primers; D004622:Embryo, Mammalian / Q000166:cytology* / Q000502:physiology*; D005109:Extracellular Matrix / Q000502:physiology* / Q000648:ultrastructure; D005775:Gastrula / Q000166:cytology* / Q000502:physiology*; D005786:Gene Expression Regulation; D006801:Humans; D007700:Kinetics
D017931:DNA Primers