Reduction in the use of animals in toxicology is an important goal despite the continued need to assess drug and chemical safety in man. However, a limitation to in vitro screening for drug and chemical toxicity is the lack of available human hepatocytes and the difficulties associated with generating fully functional hepatocytes from stem cells. Previously, we have shown that a rat pancreatic acinar cell line is capable of trans-differentiating into fully functional hepatocyte-like cells in response to glucocorticoid via a serine/threonine protein kinase mechanism alone. Here we demonstrated that differentiation only occurs with glucocorticoids, not other steroids. We also investigated the potential of human pancreatic cells to undergo the same process. Analysis of adult human pancreata at the level of mRNA, protein and by immunohistochemical staining demonstrated that long term systemic exposure to glucocorticoid therapy resulted in differentiation of exocrine tissue to hepatocyte-like tissue. Glucocorticoid treatment of human pancreatic acinar cells in culture also resulted in trans-differentiation to hepatocyte-like cells. Both in vivo and in vitro, trans-differentiation of pancreas cells to hepatocytes was associated with an induction of SGK1 variant transcripts that have been previously shown to drive B-13 differentiation to hepatocytes. Adult exocrine human pancreas therefore responds in a similar qualitative fashion to that previously observed in rodents exposed to elevated glucocorticoid – that of a differentiation into hepatocyte-like cells. Understanding the enhanced response of B-13 cells to glucocorticoid and engineering this response in a replicating human acinar cell could generate an unlimited supply of functional human hepatocytes in vitro that could be useful in a variety of applications, including screening drugs and chemicals for hepatic metabolism and toxicity.
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