Bi-directional cell contact-dependent regulation of gene expression between endothelial cells and osteoblasts in a three-dimensional spheroidal coculture model.
Multiple cell-cell interactions control bone morphogenesis and vascularization. We have employed a spheroidal coculture system of endothelial cells (EC) and osteoblasts (OB) to study cell contact-dependent gene regulation between these two cell types that may play a role in regulating OB differentiation and EC angiogenic properties. Coculture spheroids differentiate spontaneously to organize into a core of OB and a surface layer of endothelial cells. Individual spheroid culture of EC or OB leads to significant alterations in gene expression compared to standard monolayer culture (upregulation of Tie-2 in EC; upregulation of angiopoietin-2 in osteoblasts). More importantly, spheroidal coculture of endothelial cells and osteoblasts leads to significant changes of gene expression in both cell populations (upregulation of VEGFR-2 in EC; downregulation of VEGF, and upregulation of alkaline phosphatase in osteoblasts). These changes are dependent on cell-cell contact and are not seen in stimulation experiments with conditioned supernatants. Collectively, the data demonstrate complex bi-directional gene regulation mechanisms between EC and OB that are likely to play a critical role during OB differentiation and in controlling the properties of angiogenic EC.
Stahl
Andreas
A
Department of Plastic Surgery, University of Freiburg Medical Center, D-79106 Freiburg, Germany.
Wenger
Andreas
A
Weber
Holger
H
Stark
G Björn
GB
Augustin
Hellmut G
HG
Finkenzeller
Günter
G
D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D010006:Osteoblasts / Q000502:physiology*