Cell matrices

Hundreds of bioengineers are working around the world, and they have created a wide variety of applications using cell and tissue engineering research. Among the most promising applications are cell matrices and bioartificial organ assistance devices. 

Wachiralarpphaithoon, C., Iwasaki, Y, Akiyoshi, K. (2007). Enzyme-degradable phosphorylcholine porous hydrogels cross-linked with polyphosphoesters for cell matrices. Biomaterials, 28, 984-993. 

Interference with specific cell-cell and cell-matrix adhesion mechanisms is another rapidly advancing approach to therapeutically interfere with angiogenesis. Antagonistic antibodies (Vitaxin) to the integrin heterodimer av 33 have been shown to act on the blood vessels of tumors but not on the resting organ vasculature. Vitaxin demonstrated some promise in Phase II clinical trials. 

The basement membrane is a structure that supports overlying epithelial or endothelial cells. The primary fimction of the basement membrane is to anchor down the epithelium to its loose connective tissue underneath. This is achieved by cell-matrix adhesions through cell adhesion molecules. 

Weber LM, Hayda KN, Haskins K et al (2007) The effects of cell-matrix interactions on encapsulated beta-cell function within hydrogels functionalized with matrix-derived adhesive... 

S-type lectins P-Galactoside-binding animal lectins with roles In cell-cell and cell-matrix interactions... 

Sage E Regulation of interactions between cells and extracellular matrix a command performance on several stages. J Clin Invest 2001 107 781. (This article introduces a series of six articles on cell-matrix interaction. The topics covered are cell adhesion and de-adhesion, thrombospondins, syndecans, SPARC, osteopontin, and Ehlers-Danlos syndrome. All of the articles can be accessed at www.jci.org.)... 

Integrins themselves are found on nearly all cells and mediate several physiological responses, such as cell-cell and cell-matrix interactions. Three families of integrins, each family with a common beta subunit in combination with distinct alpha subunits, have been recognized. The beta 1 family, also called very late lymphocyte-activation antigen or VLA, has receptors mediating extracellular matrix interactions with molecules such as collagen, laminin, and fibronectin. Naturally, platelets contain many of the receptors of the beta 1 family. 

Cell Matrix. Guilford Phytera WYETH Genetics... 

Joh, D., Warm, E. R., Kreikemeyer, B., Speziale, P., and Hook, M. (1999). Role of fibronectin-binding MSCRAMMs in bacterial adherence and entry into mammalian cells. Matrix Biol. 18, 211-223. 

Lussier, C., Basora, N., Bouatrouss, Y., and Beaulieu, J.-F. (2000). Integrins as mediators of epithelial cell-matrix interactions in the human small intestinal mucosa. Microsc. Res. Tech. 51, 169-178. 

Disadvantages The protein expressed is accumulated within the cell matrix (intracellular) the protein does not undergo posttranslational modifications (resulting in proteins that may be structurally different or less useful to humans) the presence of lipopolysaccharides (pyrogens—microbial substances that cause fever) is likely to contaminate the product and there is a need for more extensive chromatographic purification. 

Recent advances in mass spectrometry (MS) technology have provided researchers with an unparalleled ability to identify the types and patterns of secondary biochemical modifications found on proteins in living cells. Matrix-assisted laser desorption/ionization-MS (MALDI-MS) analyses have shown, for example, that HMGA proteins in vivo are simultaneously subject to complex patterns of phosphorylation, acetylation and methylation and that, within the same cell type, different isoforms of these proteins can exhibit quite different modification patterns [33]. Furthermore, these in vivo modifications have been demonstrated to markedly alter the binding affinity of HMGA proteins for both DNA and chromatin substrates in vitro [33]. Nevertheless, due to their number and complexity, it has been difficult to determine the actual biological function(s) played by these biochemical modifications in living cells. 

Cukierman E, Pankov R, Stevens DR et al (2001) Taking cell-matrix adhesions to the third dimension. Science 294 1708-1712... 

FAK Regulation cell adhesion at cell-matrix and cell-cell contact sites (WIO)... 

It is fairly obvious that the unusual biological activity of certain collagen-GAG matrices is due to specific cell-matrix interactions which take place when these matrices are in contact with the skin wound bed or with the cut end of the nerve. The molecular character of these interactions is currently under study. 

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