Kristina Nehlsen, InSCREENeX GmbH, Braunschweig, Germany
Epithelial cells from organs like skin, intestine or lung form a tight barrier. The physiological role of this barrier is to prevent foreign organisms/substances to penetrate the body. As drug delivery through this barrier is of uttermost importance, in vitro test systems are highly desirable that mimic the in vivo situation. Such a cell system will reflect the barrier properties with regard to passive and active transport processes and in addition should produce mucus, a glycoprotein complex that protects the epithelial cells and thus the respective barrier.
We used a recently developed functional immortalization technology (CI-SCREEN) to establish novel cell lines. It is based on a small gene library that is introduced into primary cells thereby efficiently and reproducibly expanding these primary cells. The key feature of these cell systems is that they combine the positive advantage of cell lines – the unlimited cell supply – with the advantage of primary cells – the physiological relevance.
By this experimental approach we were able to generate epithelial cell lines from lung and intestine that express epithelial specific marker on RNA level as well as on protein level. Importantly, these cell lines are polarized and form specific epithelial structures like tight junctions, microvilli and desmosomes. Furthermore, they are characterized by a tight barrier with low passive diffusion. These phenotypic characteristics were stable in culture for more than 30 population doublings, which renders these cell lines an ideal tool for infection or drug absorption studies.