Fig. 4: Expression of GRP78, a regulator of unfolded protein response, in human liver.
a, Representative confocal image of LAMP2, GRP78 and hFVIII protein co-staining from one hepatocyte showing FVIII staining both in the lysosome compartment (indicating FVIII being taken up via the endocytic pathway) and in the ER compartment (FVIII protein expressed from AAV5-hFVIII-SQ). The image is from participant 4. Confocal images were acquired using a Leica TCS Sp8 white-light laser and HyD detectors at 1,024 × 1,024 pixels with an output at 300 ppi. Images were cropped and scale bars added. No additional editing was performed. Representative images of LAMP2, GRP78 and hFVIII protein co-staining from all participant biopsy samples and one normal liver are shown in Extended Data Fig. 7. b, Quantitative analysis of GRP78 intensity per cell (expressing hFVIII-SQ or not in the ER) and correlation between GRP78 intensity per cell and FVIII intensity per cell (Pearson correlation coefficient, r = −0.18; P = 0.04, two-tailed; total of 134 cells from participants 3 (28 cells), 4 (40 cells), 15 (16 cells) and 11 (50 cells), examined over one slide). c, Correlation between GRP78 RNA levels and plasma FVIII activity in the three participants with detectable plasma FVIII activity (Pearson correlation coefficient, r = −0.99; P = 0.018, two-tailed). Participants 1 and 15 had extremely low levels of FVIII RNA and thus very low/undetectable plasma FVIII activity and are therefore not included in this plot. d, GRP78 protein staining by IHC in participants 3, 4 and 11 (representative images from one section per participant). Images were captured at 2,048 × 2,048 pixels and output at 300 ppi. Scale bars, 100 µm. e, Correlation between liver GRP78 RNA and liver GRP78 IHC signals (Pearson correlation coefficient, r = 0.923; P = 0.252, two-tailed; n = 25,887 cells over one slide (participant 3), n = 37,663 cells over one slide (participant 4) and n = 9,091 cells over one slide (participant 11)). f, IHC of endogenous GRP78 protein in 32 normal human liver FFPE samples (one section per individual). Images were captured at 2,048 × 2,048 pixels and output at 300 ppi. Scale bars, 50 µm.
