Adult human exocrine pancreas differentiation to hepatocytes – potential source of a human hepatocyte progenitor for use in toxicology research

Abstract

Adult human exocrine pancreas differentiation to hepatocytes -potential source of a human hepatocyte progenitor for use in toxicology research. Toxicology Research 2013, 2(1), 80-87. Fairhall et al In vitro hepatocyte generation 3Reduction 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-differntiating 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, transdifferentiation 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 glucocorticoidthat of a differentiation into hepatocytelike 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.

Cell sources forin vitrohuman liver cell culture models

“…101 More recently, this method was also successfully applied for hepatic transdifferentiation of acinar cells from human tissue. 102 Thus, the technology could be used to generate an easily renewable and cost-efficient source of functional human hepatocytes in vitro for usage in hepatic metabolism and toxicity studies.…”

Pancreatic B-13 Cell Trans-Differentiation to Hepatocytes Is Dependent on Epigenetic-Regulated Changes in Gene Expression

“…In pancreata from patients undergoing pancreatectomies, the C and F isoform mRNAs of SGK1 where not detectable. In contrast, the pancreas from a patient exposed long term to systemic glucocorticoid treatment and whose pancreas expressed high (liver levels) of a range of hepatic proteins, expressed readily detectable levels of the C and F mRNA isoforms [ 6 ]. In human acinar cells in culture that expressed hepatic markers in response to high concentrations of DEX, both C and F isoform mRNAs were also induced, whereas in acinar cells which did not respond to DEX, there was no induction of these isoforms [ 6 ].…”

“…The B-13 cell line is a progenitor cell line with an unusual capacity to generate comparatively near-functional hepatocyte-like (B-13/H) cells after treatment with glucocorticoid hormone alone [ 1 – 3 ]. This can be achieved on simple plastic culture sub-strata and appears to be related to a pathophysiological response of both rodent and human pancreas exocrine and/or progenitor cells to elevated glucocorticoid in vivo [ 4 – 6 ]. The capacity to generate near functional hepatocyte-like cells from B-13 cells is exemplified by the expression of functional drug metabolising enzymes in the B-13/H phenotype.…”

B-13 progenitor-derived hepatocytes (B-13/H cells) model lipid dysregulation in response to drugs and chemicals

“…Hepatic phenotype (characterised by a marked phenotypic change) was routinely confirmed through expression of Cyp2e1 transcripts by RT-PCR (see below). Cyp2e1 has been shown to a sensitive marker of B-13 and both rodent and human pancreatic tissue conversion to an hepatocyte-like phenotype ( Wallace et al, 2009 , Wallace et al, 2010b , Fairhall et al, 2013b ). Fatty acids (linoleic and oleic acid) were dissolved in ethanol to give a stock with a final concentration of 200 mM each.…”