Submitted on January 30, 2008
Accepted on March 6, 2008
Systematic Assessment of the Human Osteoblast Transcriptome in Resting and Induced Primary Cells
Elin Grundberg1, Helena Brandstrom2, Kevin C.L. Lam3, Scott Gurd3, Bing Ge3, Eef Harmsen3, Andreas Kindmark2, Osten Ljunggren2, Hans Mallmin4, Olle Nilsson4, and Tomi Markuu Pastinen1*
1 McGill University and Genome Quebec Innovation Centre, Montreal, Canada; Department of Human Genetics, McGill University, Montreal, Canada
2 Department of Medical Sciences, Uppsala University, Uppsala, Sweden
3 McGill University and Genome Quebec Innovation Centre, Montreal, Canada
4 Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
* To whom correspondence should be addressed. E-mail: Tomi.Pastinen{at}mcgill.ca.
Osteoblasts are key players in bone remodeling. The accessibility of human primary osteoblast-like cells (HOb) from bone explants makes them a lucrative model for studying molecular physiology of bone turnover; for discovering novel anabolic therapeutics; and for mesenchymal cell biology in general. Relatively little is known about resting and dynamic expression profiles of HObs and no studies have been conducted to systematically assess the osteoblast transcriptome. The aim of this study was to characterize HObs and investigate signaling cascades and gene networks using genomewide expression profiling in resting and Bone Morphogenic Protein (BMP)-2 and Dexamethasone induced cells. In addition, we compared HOb gene expression with publicly available samples from the Gene Expression Omnibus.
Our data show a vast number of genes and networks expressed predominantly in HObs as compared to closely related cells such as fibroblasts or chondrocytes. For instance, genes in the insulin-like growth factor (IGF) signaling pathway were enriched in HObs (p=0.003) and included the binding proteins (IGFBP1, 2, 5) and IGF-2 and its receptor. Another HOb specific expression pattern included leptin and its receptor
(p<10-8). Furthermore, after stimulating HObs with BMP-2 or Dexamethasone, the expression of several interesting genes and pathways was observed. For instance, our data supports the role of peripheral leptin signaling in bone cell function.
In conclusion, we provide the landscape of tissue-specific and dynamic gene expression in HObs. This resource will allow utilization of osteoblasts as a model to study specific gene networks and gene families related to human bone physiology and diseases.
