title: Gene expression profiling reveals platelet-derived growth factor receptor alpha as a target of cell contact-dependent gene regulation in an endothelial cell-osteoblast co-culture model.
abstract: Angiogenesis plays an important role in bone development, repair, and remodelling. Neovascularization is furthermore a crucial step in bone tissue engineering because implantation of voluminous grafts without sufficient vascularity results in hypoxic cell death of the engineered tissue. We have previously described a co-cultivation system of human primary osteoblasts and human primary endothelial cells that was developed to improve neovascularization in bone tissue-engineering applications. In our present study, we have performed complementary deoxyribonucleic acid microarray analysis to analyze putative changes in osteoblastic gene expression upon co-cultivation of osteoblasts and endothelial cells. Transcriptional profiling revealed upregulation of 79 genes and downregulation of 62 genes in osteoblasts after co-cultivation with endothelial cells. To verify the microarray data, quantitative real-time reverse transcriptase polymerase chain reaction was carried out on selected genes. The expression of the platelet-derived growth factor receptor alpha gene in osteoblasts was analyzed in more detail, revealing that a cell contact-dependent mechanism, and not paracrine-acting diffusible factors, mediates the downregulation of this receptor in osteoblasts upon co-cultivation with endothelial cells. In summary, the data demonstrate complex gene-regulation mechanisms between endothelial cells and osteoblasts that are likely to play a role in bone morphogenesis.
authors.affiliation: Department of Plastic and Hand Surgery, University of Freiburg Medical Center, Freiburg, Germany. finkenzeller@ch11.ukl.uni-freiburg.de
authors.forename: G
authors.initials: G
authors.lastname: Finkenzeller
authors.forename: G
authors.initials: G
authors.lastname: Arabatzis
authors.forename: M
authors.initials: M
authors.lastname: Geyer
authors.forename: A
authors.initials: A
authors.lastname: Wenger
authors.forename: H
authors.initials: H
authors.lastname: Bannasch
authors.forename: G Björn
authors.initials: GB
authors.lastname: Stark
mesh_terms: D042501:Angiogenic Proteins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods; D016503:Drug Delivery Systems / Q000379:methods; D042783:Endothelial Cells / Q000166:cytology* / Q000502:physiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism*; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D042501:Angiogenic Proteins; D020796:Receptor, Platelet-Derived Growth Factor alpha