Establishment of a murine epidermal cell line suitable for in vitro and in vivo skin modelling

We have generated a murine epidermal cell line by serially passaging keratinocytes isolated from the back skin of adult mice. We have termed this cell line COCA. Cell culture is done in fully defined media and does not require feeder cells or any other coating methods.COCA retained its capacity to differentiate and stratify in response to increased calcium concentration in the cell culture medium for more than 75 passages. These cells, including late passage, can form epidermis-like structures in three-dimensional in vitro models with a well-preserved pattern of proliferation and differentiation. Furthermore, these cells form epidermis in grafting assays in vivo, and do not develop tumorigenic ability.We propose that COCA constitutes a good experimental system for in vitro and in vivo skin modelling. Also, cell lines from genetically modified mice of interest in skin biology could be established using the method we have developed. COCA keratinocytes would be a suitable control, within a similar background, when studying the biological implications of these alterations.Skin diseases affect patients of all ages worldwide. By some estimates, they affect 50 percent or more of the population at any one time and comprise over 2,000 medical conditions which can range from only mild skin problems to pathologies that are serious or even fatal. The aetiology of skin diseases is varied and some of the most severe are autoimmune and genetic disorders, including cancer.Skin tissue engineering techniques emerged in the 1980s to address the need for extensive full-thickness burns coverage in the absence of sufficient autologous skin for grafting [1-3]. In the clinical context they are also useful in treating non-healing ulcers [4,5]. In addition to its clinical applications, three-dimensional models (3D) of engineered skin are being broadly used in skin biology research, such as reducing animal experimentation (i.e. animal testing for human skin products), investigation of cell in