Fig. 6.

Restoration of OTC expression in patient-derived primary human hepatocytes in vivo.

Representative immunohistochemistry images of FRG mice engrafted with patient-derived human hepatocytes 5-weeks post-treatment. Sections were labelled with antibodies against the OTC (yellow) and human GAPDH (red) proteins in liver sections. Nuclei were stained with DAPI. Top panels show representative images from an FRG control mice that was engrafted with WT human hepatocytes but did not receive vector treatment, middle and bottom panels are representative images from engrafted patient-derived OTC-deficient hepatocytes treated with donor only (middle panels) or SaCas9-sgRNA4 and donor vectors (lower panels), respectively, at a dose of 1×10¹¹ vg/mouse of donor or 2.5×10¹⁰ vg/mouse SaCas9-sgRNA4 and 1 × 10¹¹ vg/mouse of donor. Scale bar = 50 μm. FRG, Fah^-/-Rag2^-/-Il2rg^-/; SaCas9, Staphylococcus aureus Cas9 nuclease; sgRNA, single guide RNA.