Glucocorticoid-dependent transdifferentiation of pancreatic progenitor cells into hepatocytes is dependent on transient suppression of WNT signalling

J Cell Sci. 2010 Jun 15;123(Pt 12):2103-10. doi: 10.1242/jcs.070722. Epub 2010 May 25.

Abstract

Developmentally, the pancreas and liver are closely related and pathological conditions - including elevated glucocorticoid levels - result in the appearance of hepatocytes in the pancreas. The role of the WNT signalling pathway in this process has been examined in the model transdifferentiating pancreatic acinar AR42J-B-13 (B-13) cell. Glucocorticoid treatment resulted in a transient loss of constitutive WNT3a expression, phosphorylation and depletion of beta-catenin, loss of beta-catenin nuclear localisation, and significant reductions in T-cell factor/lymphoid enhancer factor (Tcf/Lef) transcriptional activity before overt changes in phenotype into hepatocyte-like (B-13/H) cells. A return to higher Tcf/Lef transcriptional activity correlated with the re-expression of WNT3a in B-13/H cells. beta-catenin knock down alone substituted for and enhanced glucocorticoid-dependent transdifferentiation. Overexpression of a mutant beta-catenin (pt-Xbeta-cat) protein that blocked glucocorticoid-dependent suppression of Tcf/Lef activity resulted in inhibition of transdifferentiation. A small-molecule activator of Tcf/Lef transcription factors blocked glucocorticoid-dependent effects, as observed with pt-Xbeta-cat expression. Quercetin - a Tcf/Lef inhibitor - did not promote transdifferentiation into B-13/H cells, but did potentiate glucocorticoid-mediated transdifferentiation. These data demonstrate that the transdifferentiation of B-13 cells into hepatocyte-like cells in response to glucocorticoid was dependent on the repression of constitutively active WNT signalling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Transdifferentiation*
  • Cells, Cultured
  • Down-Regulation*
  • Glucocorticoids / metabolism*
  • Hepatocytes / cytology*
  • Hepatocytes / metabolism
  • Pancreas / cytology*
  • Pancreas / metabolism
  • Phosphorylation
  • Rats
  • Signal Transduction*
  • Stem Cells / cytology*
  • Stem Cells / metabolism
  • Wnt Proteins / genetics
  • Wnt Proteins / metabolism*
  • Wnt3 Protein
  • beta Catenin / genetics
  • beta Catenin / metabolism

Substances

  • Glucocorticoids
  • Wnt Proteins
  • Wnt3 Protein
  • beta Catenin