Isolation and characterization of human embryonic osteoblasts.
Human osteoblasts were obtained by migration and proliferation of cells from embryonic membranous bone on glass fragments. Light and electron microscopy analyses revealed a typical osteoblast-like appearance with high protein synthesis activity. The cells showed high alkaline phosphatase activity that was associated with plasma membranes and matrix vesicles and was 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] responsive. In contrast to the adult osteoblasts, embryonic cells could not produce detectable levels of osteocalcin, not even in the presence of 1,25(OH)2D3. Osteoblasts grown in multilayers produced a thick extracellular matrix, mainly composed of type I collagen, that mineralized in the presence of 10 mM beta-glycerophosphate. Because of their intrinsic osteogenic capacity, embryonic osteoblasts represent a valuable model for studying the mineralization process in vitro. In addition, the embryonic origin of these cells renders them a precious experimental system for the elucidation of mechanisms at the basis of differentiation of osteoblastic lineage.
Oliva
A
A
Institute of Biochemistry of Macromolecules, First Medical School, University of Naples, Italy.
Marrone
G
G
Della Ragione
F
F
Riccio
V
V
Palumbo
R
R
Rossano
F
F
Zappia
V
V
D000469:Alkaline Phosphatase / Q000378:metabolism; D002113:Calcification, Physiologic; D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation; D002455:Cell Division; D002469:Cell Separation; D002478:Cells, Cultured; D003094:Collagen / Q000032:analysis; D004622:Embryo, Mammalian; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D008854:Microscopy, Electron; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D015675:Osteocalcin / Q000096:biosynthesis
D015675:Osteocalcin; D003094:Collagen; D000469:Alkaline Phosphatase; D002117:Calcitriol