Premium
Down‐regulation of hepatocyte nuclear factor‐4α and defective zonation in livers expressing mutant Z α1‐antitrypsin
Author(s) -
Piccolo Pasquale,
Annunziata Patrizia,
Soria Leandro R.,
Attanasio Sergio,
Barbato Anna,
Castello Raffaele,
Carissimo Annamaria,
Quagliata Luca,
Terracciano Luigi M.,
BrunettiPierri Nicola
Publication year - 2017
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.29160
Subject(s) - hepatocyte , mutant , hepatocyte nuclear factors , biology , liver disease , medicine , endocrinology , hepatocyte nuclear factor 4 , hepatology , transgene , genetically modified mouse , transcription factor , biochemistry , gene , nuclear receptor , in vitro
α 1 ‐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. Conclusion : 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. (H epatology 2017;66:124–135).