Extended Data Fig. 1: Characterisation of the proliferation and differentiation of cells within the developing human liver.

a, Histology sections of key transcriptional and morphological events of primary foetal and adult liver spanning the key developmental ages analysed in this study; early foetal (6 PCW ± 4-5 days), intermediate foetal (10 PCW) and adult developmental stages; scale bars = 100 um. These immunostainings show transcriptional and morphological events including loss of AFP and increase of hepatocyte-specific antigen during development. Induction of CK19 occurs as cholangiocytes are specified from hepatoblasts, with observable increases in expression in areas of duct formation in the 10 PCW sample. Note the increase of CK8/18 expressing cells as the liver develops, and the necessary increase in vasculature indicated by CD31 expression. Importantly, VIM and CD45, staining for mesenchymal (stellate) cells and resident immune (Kupffer) cells respectively, are present throughout all stages of liver development. Scale bars = 100 um. b, Heatmap of the top 10 time-related differentially expressed genes (DEG) at each primary human hepatocyte developmental stage; Wilcoxon-Rank-Sum test, z-score>10; HB1 = hepatoblast stage 1, HB2 = hepatoblast stage 2, FH1 = foetal hepatocyte stage 1, FH2 = foetal hepatocyte stage 2, AH = adult hepatocyte. c, Immunostaining analyses showing the expression of stage-specific markers on liver tissue sections; scale bars = 50 um. HB, sample aged between 5-7 PCW; FH, sample dated at 11 PCW; AH, adult liver. d, PCA of foetal hepatoblasts/hepatocytes from 5-17 PCW and adult hepatocytes showing the progression of stages correlating to developmental time. e, UMAP representation of hepatoblast/foetal hepatocyte markers (SPINK1, G6PC, and BRI3) and WNT pathway markers (WNT5A, LGR5 and RSPO3). UMAP visualization also shows cell proliferation markers and cell cycle regulators across the hepatocyte developmental stages, showing progressive loss of proliferative capacity until the FH2 stage, which may mark commitment to the hepatocyte lineage (integrated scRNA-seq data n = 17 independent foetal livers ranging in age from 5 to 17 post-conceptional weeks and n = 16 independent adult livers). Heatmap and feature plot colour scales show “gene expression [log-normalized, scaled counts]”.