Figure 2 from SALL4 Is Required for YAP1-Dependent Malignant and Regenerative Hepatocyte-to-Cholangiocyte Reprogramming

<p>The loss of <i>Sall4</i> impairs HC-to-CCA transformation and its clonal expansion at the early stage. <b>A,</b> Schematic representation of the experimental design. <i>Sall4</i><sup><i>fl/fl</i></sup> mice underwent HDTVI with transposon vectors expressing HA-tagged <i>myrAkt</i> and <i>YAP1</i><sup><i>S127A</i></sup> (<i>AY</i>). Mice received either <i>AAV8-TBG-GFP</i> (<i>Sall4 WT</i><sup><i>GFP</i></sup>) or <i>AAV8-TBG-Cre</i> (<i>Sall4 KO</i><sup><i>hepΔ</i></sup>) prior to HDTVI, leading to HC-specific <i>Sall4</i> KO before tumor development. Livers were analyzed 2 weeks after HDTVI. qRT-PCR analysis showed relative <i>Sall4</i> expression in <i>Sall4 WT</i><sup><i>GFP</i></sup> and <i>Sall4 KO</i><sup><i>hepΔ</i></sup> livers at 2 weeks after HDTVI. <b>B,</b> Representative images of livers and corresponding overview HA-tag IHC staining from <i>Sall4 WT</i><sup><i>GFP</i></sup> and <i>Sall4 KO</i><sup><i>hepΔ</i></sup> mice, showing differences in tumor burden. <b>C,</b> Quantification of HA-tag<sup>+</sup> area per lobe (%) in <i>Sall4 WT</i><sup><i>GFP</i></sup> and <i>Sall4 KO</i><sup><i>hepΔ</i></sup> mice. <b>D,</b> IHC staining for HA-tag, Ki-67, and TUNEL staining. <b>E</b> and <b>F,</b> Quantification of Ki-67<sup>+</sup> proliferating cells (%) and TUNEL<sup>+</sup> cells in <i>Sall4 WT</i><sup><i>GFP</i></sup> and <i>Sall4 KO</i><sup><i>hepΔ</i></sup> tumors. <b>G,</b> IHC staining for HA-tag and SOX9. Red arrowheads highlight SOX9<sup>+</sup> nodules in <i>Sall4 WT</i><sup><i>GFP</i></sup> tumors, reduced in <i>Sall4 KO</i><sup><i>hepΔ</i></sup> tumors. <b>H,</b> Quantification of SOX9<sup>+</sup> tumor nodules, categorized by size (×100 μm<sup>2</sup>), comparing <i>Sall4 WT</i><sup><i>GFP</i></sup> (black) and <i>Sall4 KO</i><sup><i>hepΔ</i></sup> (red) groups. The total number of nodules is indicated in parentheses. Data are presented as the mean ± SD; Student <i>t</i> test (*, <i>P</i> < 0.05; ****, <i>P</i> < 0.0001). Scale bars, (<b>D</b>) 200 μm; <b>G,</b> 1 mm (overview), 100 µm (magnified views). ns, not significant.</p>