Spreading and actin cytoskeleton organization of cartilage and bone marrow stromal cells cocultured on various extracellular matrix proteins

Abstract

Interactions between bone marrow stromal cells (BMSCs) and cartilage cells were studied in cell cocultures. Actin cytoskeleton organization and the cell spreading on various extracellular matrix proteins (laminin 2/4, collagen type I, and fibronectin) were explored. It was found that the most pronounced morphological changes (cell shape and area, actin cytoskeleton organization) were observed in cells cultivated on fibronectin. The average spreading area of BMSCs grown on fibronectin was about four times larger than the spreading area of cartilage cells. In cocultures of these cells plated in a ratio of 1: 1, the cell spreading area on fibronectin proved to be 1.5 times less than was theoretically calculated. To clarify what influence cells have on each other, cell spreading in the conditioned medium was assayed. It was round that the BMSC spreading area in a cartilage cell conditioned medium was significantly less than in the control serum-free medium. This shows that cartilage cells are the source of factors that affect BMSC spreading.