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RESEARCH PRODUCT

The stable repression of mesenchymal program is required for hepatocyte identity: A novel role for hepatocyte nuclear factor 4α

B. ContiFrank J. GonzalezAlessandra MarchettiLaura AmiconeAlice ConigliaroLaura SantangeloCarla CicchiniTonino AlonziMarco TripodiCarmine ManconeJessica A. Bonzo

subject

Transcription FactorCellular differentiationMESH: Mice KnockoutMESH: HepatocytesMesodermMice0302 clinical medicineMESH: Liver NeoplasmsMESH: AnimalsHepatocyteHepatocyte Nuclear Factor 1-alphaMESH: Carcinoma HepatocellularRegulator geneHepatocyte differentiationMice KnockoutMESH: Mesoderm0303 health sciencesLiver NeoplasmsCell DifferentiationMESH: Transcription FactorsCell biologyHepatocyte nuclear factorsPhenotypeMESH: Models AnimalHepatocyte Nuclear Factor 4MESH: Epithelial CellsLiver Neoplasm030220 oncology & carcinogenesisModels AnimalMESH: Hepatocyte Nuclear Factor 4HumanMESH: Cell DifferentiationMESH: Cell Line TumorCarcinoma Hepatocellular[SDV.BC]Life Sciences [q-bio]/Cellular BiologyBiologyMESH: PhenotypeArticle03 medical and health scienceshepatocyte; mesenchymal program; SnailCell Line TumorAnimalsHumansMESH: Hepatocyte Nuclear Factor 1-alphaMESH: MiceTranscription factorAnimals; Carcinoma Hepatocellular; Cell Differentiation; Cell Line Tumor; Epithelial Cells; Hepatocyte Nuclear Factor 1-alpha; Hepatocyte Nuclear Factor 4; Hepatocytes; Humans; Liver Neoplasms; Mesoderm; Mice; Mice Knockout; Models Animal; Phenotype; Snail Family Transcription Factors; Transcription Factors; Hepatology030304 developmental biologyEpithelial CellMESH: HumansHepatologyAnimalMesenchymal stem cellEpithelial CellsSnail Family Transcription FactorMolecular biologyHepatocyte nuclear factor 4HepatocytesSnail Family Transcription FactorsChromatin immunoprecipitationTranscription Factors

description

The concept that cellular terminal differentiation is stably maintained once development is complete has been questioned by numerous observations showing that differentiated epithelium may undergo an epithelial-to-mesenchymal transition (EMT) program. EMT and the reverse process, mesenchymal-to-epithelial transition (MET), are typical events of development, tissue repair, and tumor progression. In this study, we aimed to clarify the molecular mechanisms underlying these phenotypic conversions in hepatocytes. Hepatocyte nuclear factor 4α (HNF4α) was overexpressed in different hepatocyte cell lines and the resulting gene expression profile was determined by real-time quantitative polymerase chain reaction. HNF4α recruitment on promoters of both mesenchymal and EMT regulator genes was determined by way of electrophoretic mobility shift assay and chromatin immunoprecipitation. The effect of HNF4α depletion was assessed in silenced cells and in the context of the whole liver of HNF4 knockout animals. Our results identified key EMT regulators and mesenchymal genes as new targets of HNF4α. HNF4α, in cooperation with its target HNF1α, directly inhibits transcription of the EMT master regulatory genes Snail, Slug, and HMGA2 and of several mesenchymal markers. HNF4α-mediated repression of EMT genes induces MET in hepatomas, and its silencing triggers the mesenchymal program in differentiated hepatocytes both in cell culture and in the whole liver. Conclusion: The pivotal role of HNF4α in the induction and maintenance of hepatocyte differentiation should also be ascribed to its capacity to continuously repress the mesenchymal program; thus, both HNF4α activator and repressor functions are necessary for the identity of hepatocytes. Copyright © 2011 American Association for the Study of Liver Diseases.

yearjournalcountryeditionlanguage
2011-06-01
10.1002/hep.24280http://hdl.handle.net/10447/241673