title: Functional and structural interactions between osteoblastic and preosteoclastic cells in vitro.
abstract: Osteoblasts are involved in the bone resorption process by regulating osteoclast maturation and activity. In order to elucidate the mechanisms underlying osteoblast/preosteoclast cell interactions, we developed an in vitro model of co-cultured human clonal cell lines of osteoclast precursors (FLG 29.1) and osteoblastic cells (Saos-2), and evaluated the migratory, adhesive, cytochemical, morphological, and biochemical properties of the co-cultured cells. In Boyden chemotactic chambers, FLG 29.1 cells exhibited a marked migratory response toward the Saos-2 cells. Moreover, they preferentially adhered to the osteoblastic monolayer. Direct co-culture of the two cell types induced: (1) positive staining for tartrate-resistant acid phosphatase in FLG 29.1 cells; (2) a decrease of the alkaline phosphatase activity expressed by Saos-2 cells; (3) the appearance of typical ultrastructural features of mature osteoclasts in FLG 29.1 cells; (4) the release into the culture medium of granulocyte-macrophage colony stimulating factor. The addition of parathyroid hormone to the co-culture further potentiated the differentiation of the preosteoclasts, the cells tending to fuse into large multinucleated elements. These in vitro interactions between osteoblasts and osteoclast precursors offer a new model for studying the mechanisms that control osteoclastogenesis in bone tissue.
authors.affiliation: Department of Human Anatomy, University of Florence, Medical School, Italy.
authors.forename: S Z
authors.initials: SZ
authors.lastname: Orlandini
authors.forename: L
authors.initials: L
authors.lastname: Formigli
authors.forename: S
authors.initials: S
authors.lastname: Benvenuti
authors.forename: L
authors.initials: L
authors.lastname: Lasagni
authors.forename: A
authors.initials: A
authors.lastname: Franchi
authors.forename: L
authors.initials: L
authors.lastname: Masi
authors.forename: P A
authors.initials: PA
authors.lastname: Bernabei
authors.forename: V
authors.initials: V
authors.lastname: Santini
authors.forename: M L
authors.initials: ML
authors.lastname: Brandi
mesh_terms: D000328:Adult; D002356:Cartilage / Q000166:cytology*; D002448:Cell Adhesion; D002450:Cell Communication; D002465:Cell Movement; D002478:Cells, Cultured; D005260:Female; D000091344:Filaggrin Proteins; D006801:Humans; D008854:Microscopy, Electron; D010006:Osteoblasts / Q000166:cytology* / Q000648:ultrastructure; D010010:Osteoclasts / Q000166:cytology* / Q000648:ultrastructure