Biomaterials Tutorial

Laminin 

Janet Cuy
University of Washington Department of Bioengineering

Laminin is a widely present protein that contributes to the formation of the extracellular matrix, particularly the basement membrane [1].  The basement membrane is a dense matrix layer found beneath many types of cell sheets, particularly the epithelium and endothelium (such as skin, or the linings of blood vessels and the respiratory and digestive tracts) [1].  The laminin in basement membranes is actually produced by a wide variety of cells, and this protein appears to be involved in an equally wide variety of activities, including cell adhesion, migration and differentiation, embryonic development, and angiogenesis (blood vessel formation) during wound healing [1,2,3]. 

In addition, there are actually many different types of laminins. Currently, at least twelve laminin isoforms (or structural variations) have been described, each of which may have a distinct, tissue-specific biological role [1]. For example, laminins are mostly involved in the interaction between cells and the extracellular matrix.  Yet, laminin-1 appears to primarily affect epithelial cells, while laminin-2 can act on muscle and nerve cells, and laminins 5, 8 and 10 are present within blood vessels [1,4]. 

Laminin is of interest in the biomaterials field because of the possibility that coating a device with the protein may improve the host-device interface.  Since cells are typically in contact with a basement membrane or some other form of extracellular matrix, a laminin coating on a biomaterial might create a more "natural" environment, and thus encourage more "natural" or "normal" interactions between cells and the material (as opposed to chronic inflammation, foreign body reactions, etc.).  For example, in the case of a tissue-engineered construct with a laminin coating, a formerly non-cell adherent material could become attractive for cell adhesion, migration and proper differentiation, thus demonstrating an improved healing response when implanted within a host [5,6,7].

However, as powerful as the potential of laminin may be as a beneficial molecule, unregulated or abnormal laminin presence may also result in powerful negative consequences.  Defects in laminin expression have been linked to conditions such as muscular dystrophy and blistering skin disease [2].  Irregular laminin production may also have a role in tumor growth and metastasis in cancer [1].  It is thus a goal of today's biomaterial scientists to attempt to fully understand the native concentration, distribution, structure, and regulation of biological molecules such as laminin, in order to most safely and effectively harness their complex and valuable properties.

References:

1. Bosman FT,  Stamenkovic I. Functional structure and composition of the extracellular matrix. J Pathol 2003; 200:423-428.  
2. Mercurio AM. Laminin receptors: achieving specificity through cooperation. Trends Cell Biol 1995; 5:419-423.
3. Li J, Zhang Y-P, Kirsner RS. Angiogenesis in wound repair: Angiogenic growth factors and the extracellular matrix. Microsc Res Tech 2003; 60:107-114.
4. Engbring JA, Kleinman HK. The basement membrane matrix in malignancy. J Pathol 2003; 200:465-470.
5. Ratner BD. Perspectives and possibilities in biomaterials science. In: Ratner BD, Hoffman AS, Schoen FJ, Lemons JE, eds. Biomaterials science: An introduction to materials in medicine. San Diego: Academic Press, 1996: 465-468.
6. Smyth JV, Walker MG. Surface precoating in the 1980s: A first taste of cell-matrix interactions. In: Zilla P and Greisler HP, eds. Tissue engineering of vascular prosthetic grafts. Austin: R.G. Landes Company, 1999: 69-77.
7. Williams DF. Bioinertness: An outdated principle. In: Zilla P and Greisler HP, eds. Tissue engineering of vascular prosthetic grafts. Austin: R.G. Landes Company, 1999: 459-462.