title: The effects of growth factors on the production of osteopontin and osteocalcin.
abstract: Bone morphogenetic proteins (BMPs) are a group of structurally related proteins in the transforming growth factor-beta (TGF-beta) family which have been shown to stimulate bone formation in vivo. Since these proteins are concentrated in the organic matrix of bone and would be released after a fracture or during bone resorption, they are likely to have a profound effect on bone remodeling and may provide a link between bone resorption and bone formation. The hypothesis of this study was that osteoblast-like cells (OBs) treated with demineralized bone matrix (DBM) would have similar levels of secretion of osteopontin (OPN) and osteocalcin (OCN) to that of OBs treated with insulin-like growth factor-1 (IGF-1), while OBs treated with bone morphogenetic protein-7, also called osteogenic protein-1 (OP-1), would secrete levels of OPN and OCN less than the DBM group. Specifically, the aims of this study were to evaluate osteoblast-like cells (MG-63 cell line) for secretion of both OPN and OCN after treatment with DBM, OP-1, or IGF-1 compared to control, at 24, 48, and 72 hours. After each incubation period, ELISA kits were used to determine the levels of osteopontin and osteocalcin production. The results clearly demonstrated a rise of OCN at 48 hours and a fall at 72 hours for all samples, including control groups. However, there was no significant difference between groups (p > 0.05). With the OPN assay, results showed no significant difference between groups until 72 hours (p = 0.022), where the IGF-1 group was significantly higher than the Control and DBM groups (p = 0.003 and p = 0.021, respectively). This information is important for understanding the signaling pathways that may be initiated in the osteoblast following stimulation with growth factors.
authors.affiliation: School of Graduate Studies in Health Sciences, Department of Orthopaedic Surgery and Rehabilitation, University of Mississippi Medical Center, Jackson, MS 39216, USA. jmdavis@orthopedics.umsmed.edu
authors.forename: Joel
authors.initials: J
authors.lastname: Davis
authors.forename: Michelle
authors.initials: M
authors.lastname: Tucci
authors.forename: Laura
authors.initials: L
authors.lastname: Franklin
authors.forename: George
authors.initials: G
authors.lastname: Russell
authors.forename: Hamed
authors.initials: H
authors.lastname: Benghuzzi
mesh_terms: D001857:Bone Matrix / Q000187:drug effects / Q000378:metabolism*; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D002113:Calcification, Physiologic / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage*; D007335:Insulin-Like Growth Factor II; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D015675:Osteocalcin / Q000096:biosynthesis*; D053495:Osteopontin; D011506:Proteins / Q000008:administration & dosage*; D012795:Sialoglycoproteins / Q000096:biosynthesis*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: C525819:BMP7 protein, human; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; C035170:IGF2 protein, human; D011506:Proteins; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D015675:Osteocalcin; D053495:Osteopontin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II