Transcription factor and liver-specific mRNA expression in facultative epithelial progenitor cells of liver and pancreas.
The pattern of mRNA expression for liver-specific proteins and liver-enriched transcription factors was studied in two models of facultative gut epithelial progenitor cells activation: D-galactosamine (GalN)-induced liver injury and dietary copper depletion leading to pancreatic acinar atrophy. After 5 weeks of copper deficiency (CuD), pancreatic acini of Fischer 344 rats underwent atrophy, associated with intense proliferation of small duct-like cells with oval-shaped nuclei. These cells resemble morphologically epithelial progenitor cells of the liver that proliferate after GalN administration. Activated pancreatic epithelial cells express mRNAs for liver-specific genes normally expressed in fetal liver, including alpha-fetoprotein, albumin, alpha-1 antitrypsin, glucose-6-phosphatase, and others, but not genes that are turned on after birth such as serine dehydratase, tyrosine aminotransferase, and multidrug resistance gene-1b. They express mRNAs for liver-enriched transcription factors including HNF-1 alpha, HNF-3 beta and gamma, HNF-4, and members of the CCAAT-enhancer binding protein (C/EBP) family. The only mRNA for a liver-enriched transcription factor not detected in the pancreas of CuD animals was HNF-3 alpha. Expression of HNF-3 alpha, beta, and gamma, and C/EBP-beta mRNA was highly activated in proliferating liver epithelial cells on days 2 and 3 after GalN injury. Increased expression of C/EBP-delta was observed first in the liver on day 1 after GalN administration and in the pancreas at 4 weeks after initiating CuD. We suggest that C/EBP-delta could be involved in the initial activation of epithelial progenitor cells and that HNF-3 alpha, beta, and gamma, and C/EBP-beta might participate in their maturation. We conclude further that pancreatic epithelial progenitor cells undertake differentiation through the hepatocyte lineage but cannot complete the differentiation program within the pancreatic milieu.
D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002455:Cell Division / Q000187:drug effects; D003300:Copper / Q000009:adverse effects / Q000172:deficiency; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004848:Epithelium / Q000737:chemistry / Q000187:drug effects; D005688:Galactosamine; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D005688:Galactosamine; D003300:Copper