Fibroblasts protein-mediated cell adhesion

Fig. 8. Schematic representation of protein-mediated cell adhesion on biomaterial surfaces. Biomaterial surface properties (such as hydrophilicity/hydrophobicity, topography, energy, and charge) affect subsequent interactions of adsorbed proteins these interactions include but are not limited to adsorbed protein type, concentration, and conformation. Changes in protein-surface interactions may alter accessibility of adhesive domains (such as the peptide sequence arginine-glycine-aspartic acid) to cells (such as osteoblasts, fibroblasts, or endothelial cells) and thus modulate cellular adhesion. (Adapted and redrawn from Schakenraad, 1996.)...

Select proteins that mediate adhesion of specific anchorage-dependent cells (such as osteoblasts, fibroblasts, and endothelial cells) on substrate surfaces have been identified (Underwood and Bennett, 1989 Thomas et al., 1997 Ayad et al, 1994). For example, adsorption of fibronectin and vitronectin on tissue-culture polystryene subsequently enhanced osteoblast, fibroblast, and endothelial cell adhesion (Underwood and Bennett, 1989). More importantly, fibronectin and vitronectin adsorption on borosilicate glass, in a competitive environment, maximized fibroblast and osteoblast adhesion, respectively (Thomas et al., 1997). Ayad et al. (1994) reported that enhanced adsorption of laminin on tissue-culture polystyrene promoted subsequent endothelial cell adhesion. These studies provided evidence that adsorption of specific protein(s) can, subsequently, control select cell adhesion on material surfaces. 

Many transmembrane proteins that mediate intracellular signaling form complexes with both intra- and extracellular proteins. For example, neural cell adhesion molecules (NCAMs) are cell-surface glycoproteins (Ch. 7). The extracellular domains of NCAMs can activate fibroblast growth factor receptors when clustered by reaction with NCAM antibodies [4] or by homotypic binding to domains of adjacent cells (see Fig. 7-2). Activation was found to sequester a complex of NCAM, (31 spectrin and PKC(32 into rafts, as defined by the operational criteria discussed on p. 28. 

Figure 12.2 Integrin-mediated matrix adhesions. Rat embryo fibroblasts (REF52) expressing yellow fluorescent protein labeled paxillin display classical focal adhesion staining, (a) The inverted fluorescent signal at the cell-substrate interface (captured with a total...

TNF-a and IL-1 are current targets of antiinflammatory drug therapy. A homotrimer of 17-kDa protein subunits whose effects include the activation of neutrophils and eosinophils, induction of COX-2, induction of proinflammatory cytokines (e.g., IL-1, IL-6), enhancement of endothelial layer permeabihty, induction of adhesion molecules by endothelial cells and leukocytes, stimulation of fibroblast proliferation, degradation of cartilage, and stimulation of bone reabsorption. Two receptors mediate these effects a 55-kDa receptor (p55) and a 75-kDa receptor (p75). Each of these receptors is found in both cell surface and soluble forms. The binding of two or three cell surface receptors to TNF-a initiates an inflammatory response. Soluble p55 also acts as a signaling receptor for inflammatory responses, whereas soluble p75 acts as an antagonist. 

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