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Hepatocyte nuclear factor 4alpha (HNF‐4α) promotes polarization and activates vectorial transport in intestinal epithelial cell
Author(s) -
Lussier Carine R,
Babeu JeanPhilippe,
Boudreau Francois
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a542-b
Subject(s) - cdx2 , biology , microbiology and biotechnology , hepatocyte nuclear factors , cell culture , gene expression , western blot , transcription factor , cell , gene , genetics , homeobox
The aim of this work was to identify transcription factors implicated in the regulation of intestinal epithelial cell (IEC) differentiation. METHODS AND RESULTS: An IEC‐6 cell line that expressed Cdx2 (IEC6‐L1) was induced to polarize and differentiate when co‐cultured 8 days with intestinal mesenchymal cells (IMC). Co‐cultured cells were harvested at days 1, 3, 5 and 8 and submitted to a gene expression analysis. HNF‐4α was not expressed at days 1 and 3 and began to be detectable at the mRNA level at day 5 when clusters of polarizing cells appeared. Western blot analysis confirmed that HNF‐4α was detectable around co‐culture day 6 and immunolocalization analysis showed that it was strictly expressed by clusters of polarized cells. The gene profiling analysis revealed numerous putative targets of HNF‐4α among the up‐regulated genes. Retroviral construct allowing the expression of HNF‐4α cDNA was used to stably infect IEC6‐L1 cells. When co‐cultured with IMC, IEC6‐L1/HNF‐4α polarized more rapidly than controls and formed dome‐like elevations. Electron microscopy confirmed that IEC6‐L1/HNF‐4α accumulated material between their bases and the subjacent IMC monolayer. CONCLUSION: HNF‐4α was recently implicated in the regulation of specific intestinal‐differentiated genes. Our results strongly suggest that HNF‐4α is implicated in IEC polarization, functional absorption and transport. (Work supported by CIHR, NSERC, FRSQ)