Table 1 Summaries of genome editing studies performed on preclinical models of inborn errors of metabolism
From: Genome editing for inborn errors of metabolism: advancing towards the clinic
IEM | Summary | Comment | Reference |
|---|---|---|---|
Hemophilia B | Targeting FIX disease locus Dual AAV8 vectors: Zinc-finger nucleases (ZFNs) Partial FIX cDNA Neonatal, hemophilia B mouse model | First in vivo study using therapeutic genome editing Low rates of homology-directed repair (HDR) detectable off-target events (<4%) | Li et al., 2011 [33] |
Hemophilia B | Targeting Alb safe harbor Dual AAV8 vectors: ZFNs Partial FIX cDNA Adult C57BL/6+ hemophilia B mouse models | Low rate of NHEJ-mediated correction (0.5% fused mRNA transcripts) Due to integration in Alb, secretion of corrected protein led to therapeutic levels of circulating FIX Duration of effect 12Â weeks after single treatment | Sharma et al., 2015 [34] |
Hemophilia B | Targeting Alb safe harbor No endonuclease Single AAV8 vector targeting FIX donor as 2A fusion to Alb Neonatal + adult hemophilia B mice | No off-target Low rate of HDR (0.1% fused mRNA transcripts) Addition of amino-terminal proline to FIX due to 2A peptide | Barzel et al., 2015 [35] |
Hereditary Tyrosinemia Type I | Targeting Fah disease locus CRISPR: SpCas9/gRNA + ssDNA oligonucleotide Naked DNA | Positive selection of hereditary tyrosinemia type I (HT-I) mouse model Low HDR (0.4%); increased to 33.5% after 30 days Off-target for Fah gRNA < 0.3% (NIH3T3 cells) | Yin et al., 2014 [81] |
Hereditary Tyrosinemia Type I | Targeting Fah disease locus CRISPR: SpCas9 mRNA, LNP delivery (nano.Cas9) FAH2 gRNA + donor (AAV-HDR) | Transient expression SpCas9 (LNP) HDR 6% without selection Low level off-target cutting (Hepa1-6 cells) | Yin et al., 2016 [37] |
Hereditary Tyrosinemia Type I | Targeting Hpd (disease locus) CRISPR: SpCas9 + 2 gRNAs non-homologous end joining (NHEJ) Naked DNA | Positive selection of HT-I mouse model Metabolic reprogramming Multiplex editing (2 guides) 8% NHEJ efficiency at both cut sites 1-week post 68% efficiency 4-weeks post (+ selection) | Pankowicz et al., 2016 [39] |
Hereditary Tyrosinemia Type I | Targeting Alb safe harbor No endonuclease rAAV8: Hpd shRNA + hFIX C57Bl/6 wild-type mice | Inducible positive selection using CEPHOBA Initial homologous recombination < 1%; after selection 50% | Nygaard et al., 2016 [41] |
Ornithine Transcarbamylase Deficiency | Targeting Otc disease locus CRISPR: SaCas9 + gRNA Dual AAV8 vectors: SaCas9 + gRNA-donor Otc mouse model | Smaller Cas9 orthologue S. aureus 10% HDR in neonatal mice Large deletions in adult mice ➔ hyperammonemia | Yang et al., 2016 [43] |
Lysosomal Storage Disorders (MPSI, MPSII) | Targeting Alb safe harbor Dual AAV8 vectors: ZFNs + donor C57Bl/6 wild-type mice | Therapeutic protein detectable by Western blot Phase I clinical trial MPSI: 3 AAV6 vectors: ZFN + ZFN + donor | Sharma et al., 2015 [34] |
Glycogen Storage Disorder Type Ia | Targeting Rosa26 safe harbor Dual AAV8/AAV9 ZFNs + donor GSD1a mouse model | AAV8: Improvement in survival AAV9: Improvement in biochemical phenotype Positive selection of corrected hepatocytes | Landau et al., 2016 [44] |