Survival Advantage of Both Human Hepatocyte Xenografts and Genome-Edited Hepatocytes for Treatment of α-1 Antitrypsin Deficiency

Florie Borel, Qiushi Tang, Gwladys Gernoux, Cynthia Greer, Ziqiong Wang, Adi Barzel, Mark A. Kay, Leonard D. Shultz, Dale L. Greiner, Terence R. Flotte, Michael A. Brehm, Christian Mueller

Research output: Contribution to journalArticlepeer-review

Abstract

Hepatocytes represent an important target for gene therapy and editing of single-gene disorders. In α-1 antitrypsin (AAT) deficiency, one missense mutation results in impaired secretion of AAT. In most patients, lung damage occurs due to a lack of AAT-mediated protection of lung elastin from neutrophil elastase. In some patients, accumulation of misfolded PiZ mutant AAT protein triggers hepatocyte injury, leading to inflammation and cirrhosis. We hypothesized that correcting the Z mutant defect in hepatocytes would confer a selective advantage for repopulation of hepatocytes within an intact liver. A human PiZ allele was crossed onto an immune-deficient (NSG) strain to create a recipient strain (NSG-PiZ) for human hepatocyte xenotransplantation. Results indicate that NSG-PiZ recipients support heightened engraftment of normal human primary hepatocytes as compared with NSG recipients. This model can therefore be used to test hepatocyte cell therapies for AATD, but more broadly it serves as a simple, highly reproducible liver xenograft model. Finally, a promoterless adeno-associated virus (AAV) vector, expressing a wild-type AAT and a synthetic miRNA to silence the endogenous allele, was integrated into the albumin locus. This gene-editing approach leads to a selective advantage of edited hepatocytes, by silencing the mutant protein and augmenting normal AAT production, and improvement of the liver pathology. Borel et al. describe two studies based on misfolded human α-1 antitrypsin (A1AT). First, when A1AT is expressed in livers of NSG, mice it allows for reproducible engraftment of human hepatocytes. Second, gene editing of hepatocytes to decrease misfolded protein results in expansion of corrected cells and amelioration of liver disease.

Original languageEnglish
Pages (from-to)2477-2489
Number of pages13
JournalMolecular Therapy
Volume25
Issue number11
DOIs
StatePublished - 1 Nov 2017

Keywords

  • A1AT
  • AAT
  • AATD
  • AAV
  • RNAi
  • gene editing
  • humanized liver mouse model
  • liver regeneration
  • liver xenograft
  • miRNA
  • nuclease-free genome editing
  • shRNA
  • α-1 antitrypsin deficiency

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