title: Down-regulation of hepatocyte nuclear factor-4α and defective zonation in livers expressing mutant Z α1-antitrypsin.
abstract: α1-Antitrypsin (AAT) deficiency is one of the most common genetic disorders and the liver disease due to the Z mutant of AAT (ATZ) is a prototype of conformational disorder due to protein misfolding with consequent aberrant intermolecular protein aggregation. In the present study, we found that livers of PiZ transgenic mice expressing human ATZ have altered expression of a network of hepatocyte transcriptional factors, including hepatocyte nuclear factor-4α, that is early down-regulated and induces a transcriptional repression of ATZ expression. Reduced hepatocyte nuclear factor-4α was associated with activation of β-catenin, which regulates liver zonation. Livers of PiZ mice and human patients with AAT deficiency were both found to have a severe perturbation of liver zonation. Functionally, PiZ mice showed a severe defect of ureagenesis, as shown by increased baseline ammonia, and reduced urea production and survival after an ammonia challenge. Down-regulation of hepatocyte nuclear factor-4α expression and defective zonation in livers have not been recognized so far as features of the liver disease caused by ATZ and are likely involved in metabolic disturbances and in the increased risk of hepatocellular carcinoma in patients with AAT deficiency.
  
  
  
  The findings of this study are consistent with the concept that abnormal AAT protein conformation and intrahepatic accumulation have broad effects on metabolic liver functions. (Hepatology 2017;66:124-135).
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Piccolo
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Annunziata
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Leandro R
authors.initials: LR
authors.lastname: Soria
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Attanasio
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Barbato
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Castello
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Carissimo
authors.affiliation: Molecular Pathology Division, Institute of Pathology, University of Basel, Basel, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Quagliata
authors.affiliation: Molecular Pathology Division, Institute of Pathology, University of Basel, Basel, Switzerland.
authors.forename: Luigi M
authors.initials: LM
authors.lastname: Terracciano
authors.affiliation: Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy.|Department of Translational Medicine, Federico II University, Naples, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Brunetti-Pierri
mesh_terms: D000375:Aging / Q000235:genetics; D000704:Analysis of Variance; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D004195:Disease Models, Animal; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D051557:Hepatocyte Nuclear Factor 4 / Q000235:genetics*; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation; D011897:Random Allocation; D018709:Statistics, Nonparametric; D019896:alpha 1-Antitrypsin Deficiency / Q000235:genetics* / Q000473:pathology
chemical_list: D051557:Hepatocyte Nuclear Factor 4; C496593:Hnf4a protein, mouse