Integrin Expression and Collagen Type Ii Implicated in Maintenance of Chondrocyte Shape in Monolayer Culture: An Immunomorphological Study

Abstract

Chondrocytes grown in monolayer culture at low density, with serum added, either dedifferentiate after several days whereby their cell shape or they are overgrown by fibroblast-like cells. The aim of this study was to optimize the cultivation of chondrocytes in monolayer culture and to slow down their transformation or their overgrowth by fibroblast-like cells. For this purpose freshly isolated chondrocytes of cartilage anlagen from 17-day-old mouse embryos were grown on plastic or collagen type II-coated substrates. With this model: (a) chondrocytes grown on plastic substrates had almost completely changed to fibroblast-like cells after 5 days in culture. (b) When grown on collagen type II, the chondrocytes maintained their round phenotype for more than 2 weeks in culture. (c) Immunomorphological investigations showed that chondrocytes produce collagen type II and fibronectin and express specific surface receptors (integrins of the beta 1-group) on the membrane from day 1 until the end of the culture period when grown on collagen type II. (d) Treatment with beta 1-integrin antibodies clearly reduces chondrocyte adhesion on collagen type II by about 70%. Hence, these data indicate that the most probable influence of collagen type II on cellular behaviour depends on the integrins participating in a chondrocyte-collagen type II interaction, and this model represents a pure chondrocyte culture which allows cell growth for an extended period.

Type I and II collagen regulation of chondrogenic differentiation by mesenchymal progenitor cells

“…This increased the syntheses of type I1 collagen and GAG [37,32,33]. Cell-matrix interactions via cell surface receptors transduce extracellular signals inwards to regulate the cell phenotype [34].…”

Sirtuin-1 (SIRT1) Is Required for Promoting Chondrogenic Differentiation of Mesenchymal Stem Cells

“…Electron Microscopic Evaluation-To evaluate chondrogenic ultrastructure, transmission electron microscopy was performed as described previously in detail (39). Briefly, cultures were fixed for 1 h in Karnovsky fixative, post-fixed in 1% OsO 4 solution, dehydrated in serial alcohol dilutions, and embedded in Epon (Plano, Germany).…”

An RGD-restricted substrate interface is sufficient for the adhesion, growth and cartilage forming capacity of human chondrocytes

“…It was found that compared to a bare plastic substrate, chicken epiphysial chondrocytes longer retained their native morphology on plastic precoated with type II collagen (Shakibei et al, 1997), and rabbit articular chondrocytes better preserved their phenotype on type I collagen (Kino-Oka et al, 2005). In contrast, other studies showed that the expression of type I and II collagen by chondrocytes was not altered in response to substrates coated with either type I or II collagen or fibronectin (Brodkin et al, 2004;Barbero et al, 2006).…”