LAUSR

Key liver functions including protein synthesis, carbohydrate metabolism and detoxification are performed by specific populations of hepatocytes which are defined by their relative position within the liver lobules. On a molecular level, the functional heterogeneity with periportal and pericentral phenotypes, so-called metabolic liver zonation, is mainly established by a gradient of canonical Wnt-signalling activity. Since the relevant physiological cues are missing in in vitro liver models, they fail to reflect the functional heterogeneity and thus lack many liver functions. We synthetically re-engineered Wnt-signalling in murine and human hepatocytes using a Doxycycline dependent cassette for externally controlled, digital expression of stabilised β-catenin. Thereby, we achieved adjustable mosaic-like activation of Wnt-signalling in in vitro cultured hepatocytes that was resistant towards negative feedback loops. This allows the establishment of long-term stable periportal and pericentral phenotypes that mimick the heterogeneity observed in vivo. The in vitro zonated hepatocytes show differential expression of drug-metabolising enzymes and associated differential toxicity and higher levels of autophagy. Further, recombinant adeno-associated virus and hepatitis C virus preferentially transduce the pericentral zonation phenotype suggesting a so far unappreciated bias of these viruses. These tightly controlled in vivo-like systems will be important for studies evaluating aspects of liver zonation and for assessment of drug toxicity for mouse and man.