The extracellular matrix (ECM) consists of a complex mixture of biochemical and physical stimuli that together regulate cell behavior. Previously we showed that films composed of Type I collagen fibrils induce reproducible and physiologically relevant cell behaviors and that the mechanical properties of the fibrils can be modulated to test the effect of environmental mechanics on cells. In the present study, we engineered extracellular matrices consisting of a combination of fibrillar collagen plus fibronectin and showed that cells respond to this matrix distinctively. In particular, cells exhibit intermediate phenotypic characteristics compared to their response to collagen or fibronectin alone. These responses can be further controlled by varying fibronectin density. Cell engagement with the surface could be blocked by peptides containing the sequence Arginine-Glycine-Aspartic acid (RGD) or antibodies to α1 integrin, suggesting that cell-matrix engagement was mediated by integrin receptors that recognize both collagen and fibronectin. Regardless of the integrin engagement, cells are sensitive to the mechanical differences of the matrix. Overall, these results indicated that the fibronectin/collagen combined matrix may be a useful model system for quantifying the relative contributions of multiple ECM factors on cell responses and the underlying signaling pathways.
Pub Type: Journals
ECM, Fibronectin, Collagen, Stiffness