Matrix mineralization controls gene expression in osteoblasts. Matrix mineralization controls gene expression in osteoblasts

Osteoblasts are adherent cells. Under physiological conditions they attach to mineralized and non-mineralized osseous surfaces. However, how exactly osteoblasts respond to these different osseous surfaces is largely unknown. Our hypothesis was that the state of matrix mineralization provides a functional signal to osteoblasts. To assess the osteoblast response to mineralized compared to demineralized osseous surfaces, we assessed the transcriptom. Overall design: Porcine tibia was cut into 16 slices with 600 µm thickness each. 8 slices were demineralized with 0,5 M EDTA over 16 hrs, while the other 8 slices were left in their native condition. All slices were sterilized over 16 hrs, using 2% PAA (peracedic acid, Bioxal SA, Chalon-sur-Saône, France). MG-63 cells were seeded onto the osseous surfaces (200,000/cm²), followed by incubation of the samples for 72 hrs (37 °C, 5% CO2). After incubation, the adhesive cells were mechanically removed using a cell scraper. For each surface (mineralized or demineralized), the 8 samples were randomly pooled in pairs, resulting in an n=4 per surface group. RNA was extracted in Trizol.