Collagen I is one of the most abundant extracellular matrix (ECM) proteins in mammals and is an important structural component in connective tissues, bones, teeth, skin, heart, and lungs (1, 2). Collagen I is commonly used for biomedical purposes including providing an ECM microenvironment for cell attachment, proliferation, and mesenchymal stem cell growth and differentiation to the osteogenic lineage (1, 3, 4). Furthermore, type I Collagen hydrogels are a promising scaffold for engineering tissues and tumors (4). Collagen type I can be extracted from numerous sources including mammals, most commonly bovine and porcine, fish, amphibians, and birds (1, 4). Structurally, Collagen I is a heterotrimer comprised of two alpha-1 chains and one alpha-2 chain that together forms a triple helix (1, 3, 5). Each alpha chain is primarily formed by glycine, proline, and hydroxyproline repeats with the alpha-1 chains having a theoretical molecular weight of 139 kDa and 129 kDa for the alpha-2 chain (3). The dimeric form of Collagen I has a theoretical molecular weight of ~270 kDa while the trimeric form is >400 kDa (3, 5).
A variety of disease pathologies have been associated with mutations in or disruptions in collagen type I. Osteogenesis imperfecta, also known as brittle bone disease, is caused by autosomal dominant mutations in Collagen type I encoding genes and characterized by fragile bones and skeletal deformities (6). Ehlers-Danlos syndromes (EDS) is another disorder that affects soft connective tissue and its various clinical subtypes are associated with different mutations in Collagen I (7).
Alternative names for Collagen I includes alpha-1 type I collagen, alpha1(I) procollagen, CAFYD, COL1A1, collagen alpha 1 chain type I, collagen alpha-1(I) chain, EDSARTH1, EDSC, OI1, OI2, OI3, OI4, pro-alpha-1 collagen type 1, type I proalpha 1, and type I procollagen alpha 1 chain.
1. Chowdhury, S. R., Mh Busra, M. F., Lokanathan, Y., Ng, M. H., Law, J. X., Cletus, U. C., & Binti Haji Idrus, R. (2018). Collagen Type I: A Versatile Biomaterial. Advances in experimental medicine and biology. https://doi.org/10.1007/978-981-13-0947-2_21
2. Kisling, A., Lust, R. M., & Katwa, L. C. (2019). What is the role of peptide fragments of collagen I and IV in health and disease?. Life sciences. https://doi.org/10.1016/j.lfs.2019.04.042
3. Kwon, D., Kang, G. S., Han, D. K., Park, K., Kim, J. H., & Lee, S. H. (2014). Establishment and characterization of human engineered cells stably expressing large extracellular matrix proteins. Archives of pharmacal research. https://doi.org/10.1007/s12272-013-0294-0
4. Antoine, E. E., Vlachos, P. P., & Rylander, M. N. (2014). Review of collagen I hydrogels for bioengineered tissue microenvironments: characterization of mechanics, structure, and transport. Tissue engineering. Part B, Reviews. https://doi.org/10.1089/ten.TEB.2014.0086
5. Leon-Lopez, A., Morales-Penaloza, A., Martinez-Juarez, V. M., Vargas-Torres, A., Zeugolis, D. I., & Aguirre-alvarez, G. (2019). Hydrolyzed Collagen-Sources and Applications. Molecules (Basel, Switzerland). https://doi.org/10.3390/molecules24224031
6. Marini, J. C., Forlino, A., Bachinger, H. P., Bishop, N. J., Byers, P. H., Paepe, A., Fassier, F., Fratzl-Zelman, N., Kozloff, K. M., Krakow, D., Montpetit, K., & Semler, O. (2017). Osteogenesis imperfecta. Nature reviews. Disease primers. https://doi.org/10.1038/nrdp.2017.52
7. Callewaert, B., Malfait, F., Loeys, B., & De Paepe, A. (2008). Ehlers-Danlos syndromes and Marfan syndrome. Best practice & research. Clinical rheumatology, 22(1), 165-189. https://doi.org/10.1016/j.berh.2007.12.005