Genetic Portrait of Osteoblast-Like Cells Cultured on PerioGlas
PerioGlas (PG) is an alloplastic material used for grafting periodontal osseous defects since 1995. In animal models it has been histologically proven that PG achieves good repair of surgically created defects. In clinical trials, PG has been shown to be effective as an adjunct to conventional surgery in treating intrabony defects. Because the molecular events by which PG is able to alter osteoblast activity to promote bone formation are poorly understood, we investigated genes that are differently regulated in osteoblast-like cells exposed to PG. Bone formation can be attributable to ostegenesis (ie, direct stimulation of osteoblast to produce new bone), osteoconduction (which operates like a scaffold), or both processes. By using DNA microarrays containing 20 000 oligonucleotides, we identified several genes in which expression was significantly downregulated in a MG63 cell line cultured with PerioGlas (US Biomaterials Corp, Alachua, Fla). Specifically, PG is able to downregulate some functional activities of osteoblast-like cells: it acts on signal transduction, especially on the transforming growth factor beta (TGFB) paracrine network; it inhibits apoptosis; it decreases cell adhesion with consequent enhancement of cell mobility and migration; and it acts on bone marrow stem cells (ie, CD34). In conclusion, PG acts on bone formation by determining both osteoconduction (as demonstrated by the reduced cell adhesion) and ostegenesis (as shown by TGFB-related proteins and stem cell markers).Abstract
Statistical analysis of microarray plot (SAM) of MG63 treated for 24 hours with PerioGlas at the concentration of 0.04 g/mL. Expected differentially expressed genes are reported in the x axis whereas observed differentially expressed genes are in the y axis. Downregulated genes (green dots) are located in the lower left-hand side of the diagram; upregulated genes (red dots) are in the upper right-hand side; genes with different expression that are not statistically significant differences are black dots. Blue parallel diagonal lines represent the cutoff limits; the middle diagonal line indicates the equal value of observed and expected differentially expressed genes
Contributor Notes
Vittoria Perrotti is a PhD student and Adriano Piattelli is a full professor, Dental Clinic, University of Chieti. Address correspondence to Professor Adriano Piattelli, Dental School, University of Chieti Via F. Sciucchi 63, 66100 Chieti, Italy (apiattelli@unich.it).
Francesco Carinci is an associate professor of maxillofacial surgery, Annalisa Palmieri and Marcella Martinelli are postdoctoral fellows in the Department of Embryology and Morphology, and Giorgio Brunelli is a fellow in maxillofacial surgery, University of Ferrara.
Marzia Arlotti is a PhD student and Furio Pezzetti is an associate professor of histology, Institute of Histology, University of Bologna, and Center of Molecular Genetics, CARISBO Foundation, Bologna, Italy.