A comparison of type I collagen, fibronectin, and vitronectin in supporting adhesion of mechanically strained osteoblasts.
J Bone Miner Res
; 17(3): 481-92, 2002 Mar.
Article
em En
| MEDLINE
| ID: mdl-11874239
ABSTRACT
We used an adhesion assay for cells cultured under high dynamic strain to measure human osteoblast-like HOS cell adherence to immobilized type I collagen, fibronectin, and vitronectin. These conditions were designed to model the increased forces present at unstable fractures or loose joint prostheses. At a constant, low protein-coating density (1000 molecules/microm2) and 20% cyclic strain for 24 h, type I collagen, fibronectin, and vitronectin supported 24.6 +/- 2%, 16.7 +/- 3%, and 1.1 +/- 1% adherence, respectively, which paralleled the relative number of integrin-binding sites in each protein. Thus, when the number of available binding sites was limited, strain resistance was proportional to the number of integrin-ligand interactions. In contrast, at high protein-coating densities (> or = 2,500 molecules/microm2), vitronectin supported greater adherence (45.7 +/- 2%) when compared with type I collagen (37 +/- 2%) or fibronectin (34.8 +/- 2%) and directed constitutive expression of osteopontin (OPN), which suggested that there exist discrete signals on vitronectin receptor occupancy that promoted cell adherence and survival under strain. Integrin-mediated binding was necessary for resistance to strain, as evidenced by the low levels of strain resistance observed when cells were adherent in a nonintegrin-dependent manner. These findings support the utilization of at least two distinct mechanisms (i.e., tensegrity and integrin-mediated signal transduction) by HOS cells to remain adherent and viable on exposure to mechanical forces.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Osteoblastos
/
Fibronectinas
/
Vitronectina
/
Colágeno Tipo I
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Bone Miner Res
Assunto da revista:
METABOLISMO
/
ORTOPEDIA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos