title: Proteomic analysis of human osteoblastic cells: relevant proteins and functional categories for differentiation.
abstract: Osteoblasts are the bone forming cells, capable of secreting an extracellular matrix with mineralization potential. The exact mechanism by which osteoblasts differentiate and form a mineralized extracellular matrix is presently not fully understood. To increase our knowledge about this process, we conducted proteomics analysis in human immortalized preosteoblasts (SV-HFO) able to differentiate and mineralize. We identified 381 proteins expressed during the time course of osteoblast differentiation. Gene ontology analysis revealed an overrepresentation of protein categories established as important players for osteoblast differentiation, bone formation, and mineralization such as pyrophosphatases. Proteins involved in antigen presentation, energy metabolism and cytoskeleton rearrangement constitute other overrepresented processes, whose function, albeit interesting, is not fully understood in the context of osteoblast differentiation and bone formation. Correlation analysis, based on quantitative data, revealed a biphasic osteoblast differentiation, encompassing a premineralization and a mineralization period. Identified differentially expressed proteins between mineralized and nonmineralized cells include cytoskeleton (e.g., CCT2, PLEC1, and FLNA) and extracellular matrix constituents (FN1, ANXA2, and LGALS1) among others. FT-ICR-MS data obtained for FN1, ANXA2, and LMNA shows a specific regulation of these proteins during the different phases of osteoblast differentiation. Taken together, this study increases our understanding of the proteomics changes that accompany osteoblast differentiation and may permit the discovery of novel modulators of bone formation.
authors.affiliation: Department of Internal Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Rodrigo D A M
authors.initials: RD
authors.lastname: Alves
authors.forename: Marco
authors.initials: M
authors.lastname: Eijken
authors.forename: Sigrid
authors.initials: S
authors.lastname: Swagemakers
authors.forename: H
authors.initials: H
authors.lastname: Chiba
authors.forename: Mark K
authors.initials: MK
authors.lastname: Titulaer
authors.forename: Peter C
authors.initials: PC
authors.lastname: Burgers
authors.forename: Theo M
authors.initials: TM
authors.lastname: Luider
authors.forename: Johannes P T M
authors.initials: JP
authors.lastname: van Leeuwen
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002113:Calcification, Physiologic; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002461:Cell Line, Transformed; D019295:Computational Biology; D006801:Humans; D007150:Immunohistochemistry; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D020543:Proteome / Q000737:chemistry* / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D020543:Proteome; D000469:Alkaline Phosphatase; D002118:Calcium