Extracellular matrix integrins

Integrins are widely expressed cell surface receptors involved in cell-cell adhesion and interactions of cells with the extracellular matrix. Integrins enable the cellular uptake of structures as large as bacteria and as small as viruses. Thus, they constitute good targets for developing selective gene delivery systems. 

Wilson E, Sidhir K, Ives HE. Mechanical strain of rat vascular smooth muscle cells is sensed by specific extracellular matrix/integrin interactions. J Clin Invest. 1995 96 2364-2372. 

Mousa SA, Lorelli W, Campochiaro PA. 1999. Role of hypoxia and extracellular matrix-integrin binding in the modulation of angiogenic growth factors secretion by retinal pigmented epithelial cells. J Cell Biochem 74 135-143. 

Damsky, C. H. 1999. Extracellular matrix - integrin interactions in osteoblast function and tissue remodeling. Bone, 25, 95-96. 

Keywords Biomaterials Cell-biomaterial interactions Extracellular matrix Integrins Adhesion Immune response Biocompatibility Biomaterial surface modifications Topography Morphology Porosity Hydrophobicity Age-related macular degeneration Retinal pigmented epithelial cells Retina Brach s membrane... 

Brizzi, M.F., Tarone, G., Defilippi, R Extracellular matrix, integrins, and growth factors as tailors of the stem ceU niche. Curr. Opin. Cell Biol. 24,645-651 (2012)... 

Integrins, selectins, cadherins, claudins and other cell adhesion molecules are involved in the interaction of cells with other cells or with extracellular matrix components. Some of them also serve as receptors by inducing outside-in or additional inside-out signaling. 

Integrins constitute a large family of a (3 heterodimeric cell surface, transmembrane proteins that interact with a large number of extracellular matrix components through a metal ion-dependent interaction. The term integrin reflects their function in integrating cell adhesion and migration with the cystoskeleton. 

Petrie TA, Garcia AJ (2009) Extracellular matrix-derived ligands for seledive integrin binding to control cell function. In Puleo DA (ed) Biological interactions on materials surfaces. Springer, New York... 

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. 

Adhesion molecules such as LI, neural cell adhesion molecule (N-CAM) and N-cadherin promote axonal regeneration by homophilic interactions between axons and Schwann cell surfaces (see Ch. 7). The expression of p75 (low affinity NGF receptor, Ch. 27) is also increased at the Schwann cell surface after injury. Extracellular matrix molecules, such as tenascin and proteoglycans, increase the regenerative potential of damaged peripheral nerves by binding to integrins on the axonal surface. 

The integrins comprise a family of cell-surface proteins that are involved in adhesion, a process vital for many processes, such as anchorage, migration, growth and differentiation. Cells may adhere to other cells (cell-cell adhesion) or may interact with soluble molecules that constitute the extracellular matrix (cell-extracellular matrix). The integrins are linked to elements of the cytoskeleton, and so they provide a bridge between the external cellular environment and intracellular activation processes. 

Type I collagen can interact with various other molecules in the extracellular matrix and on the cell surface. Cell receptors of type I collagen have been identified and include the heterodimeric integrin family receptors, ctl, 0 2, olO, and ol 1, especially o2/3l, the receptor tyrosine kinase discoidin domain receptor (DDR), and the heparan sulfate membrane proteoglycan syndecan family... 

The possibility of binding RGD to different receptors is probably caused by a different spatial conformation of RGD due to the vicinity of different amino acids or existence of different synergistic sequences on various extracellular matrix (ECM) molecules. At the same time, one type of integrin can bind more ligands [38-40]. 

Figure. 4. Principle of the cell adhesion to artificial materials. In cell culture media or body fluids, the material is spontaneously adsorbed with cell adhesion-mediating extracellular matrix proteins (e g., vitronectin, fibronectin). The cells then adhere to specific amino acid sequences of these proteins by their adhesion receptors of integrin or non-integrin type [38-41].

Transforming growth factor beta TGEP many cells stimulates deposition of extracellular matrix, by increasing synthesis of proteins such as fibronectin and the integrins ... 

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