Gene Expression Profile of Osteogenic Cells Derived from Human Bone Marrow and Trabecular Bone II

The aim of this study was to describe the gene expression patterns related to the differentiation and mineralization of bone-forming cells, including activation and/or repression of osteogenic or non-osteogenic pathways, remodeling of cell architecture, cell adhesion, cell communication, and assembly of extracellular matrix. The study implied patient selection, tissue collection, isolation and culture of human marrow stromal cells (hMSC) and osteoblasts (hOB), and characterization of bone-forming cells. RNA samples were collected at defined time points, in order to understand the regulation of gene expression during the processes of cell differentiation/mineralization that occur during bone repair. Transcriptome analysis was performed by using the Affymetrix GeneChip microarray technology platform and GeneChip® Human Genome U133 Plus 2.0 Array. Our results help to design a gene expression profile of bone-forming cells during specific steps of osteogenic differentiation. These findings offer an useful tool to monitor the behaviour of osteogenic precursors cultured in presence of exogenous stimuli, i.e. growth factors, or onto 3D scaffolds for bone engineering. Moreover, they can contribute to identify and clarify the role of new genes for a better understanding of the molecular mechanisms regulating osteogenesis. Keywords: time course hMSC were derived from mononuclear cells (MNC) of bone marrow aspirates of four patients. MNC cultures were maintained in differentiation medium containing ascorbic acid-2 phosphate and dexamethasone, and hMSC were collected at different time points. The experimental protocol was specifically devised to mark five steps of hMSC differentiation (MD). The reference sample consisted in MNCs before the addition of differentiation medium (MD1).