PPARα activation promotes LPC-mediated liver regeneration. (A) Scheme illustrating LPC-mediated liver regeneration in Tg(fabp10a:pt-β-catenin) fish and GW7647 treatment stage. (B) qRT-PCR data showing the relative expression levels of hepatocyte (cyp7a1, gc, serpina1, ces2) and BEC (her9, epcam) markers between DMSO- and GW7647-treated Tg(fabp10a:pt-β-catenin) livers at 14 dpf. (C) Section in situ hybridization images showing pparaa expression in Tg(fabp10a:pt-β-catenin) livers at 14 dpf. (D) Immunofluorescence images showing Bhmt expression in 15-dpf Tg(fabp10a:pt-β-catenin) livers treated with 1 μM GW7647 or 7 μM CAY10599. (E) Section in situ hybridization images showing the expression of hepatocyte (cyp7a1, gc, serpina1) and BEC (epcam) markers in 15-dpf Tg(fabp10a:pt-β-catenin) livers. For quantification, larvae were grouped into +/− (cyp7a1, gc, epcam) or strong/medium/weak (serpina1) based on gene expression levels. (F) Immunofluorescence images showing the expression of Abcb11 (red) and Bhmt (grey) in 13-dpf Tg(fabp10a:pt-β-catenin) livers. Violin plot graphs show the quantification of the number of Abcb11⁺ canaliculi per liver area; median and quartiles are indicated by red dashed and black dotted lines, respectively. Dashed lines outline the livers (C–E). Numbers in the upper right corner indicate the proportion of larvae exhibiting the phenotype shown (D, E). Data are represented as mean ± SD (B). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; statistical significance was calculated using an unpaired two-tailed t-test (B, F), Fisher’s exact test (E: cyp7a1, gc, epcam), and chi-square test (E: serpina1). Scale bars, 50 μm.

PPARα activation reduces YAP signaling in Tg(fabp10a:pt-β-catenin) livers. (A) Heatmap showing the differentially expressed hepatocyte, BEC, and YAP-related genes between DMSO- and GW7647-treated groups. Each column represents an independent sample (n = 3). (B) Upstream analysis showing the top 10 significantly upregulated gene sets of transcriptional regulators in the GW7647-treated group. (C) Pathway analysis showing biological pathways significantly induced in the GW7647-treated group. (D) Immunofluorescence images showing the expression of hCCN2:GFP and Anxa4 in control and Tg(fabp10a:pt-β-catenin) livers at 14 dpf. Dashed lines outline the livers. (E) qRT-PCR data showing the relative expression levels of two YAP target genes (ccn1, ccn2) and yap1 between DMSO- and GW7647-treated Tg(fabp10a:pt-β-catenin) livers at 14 dpf. **P < 0.01; statistical significance was calculated using an unpaired two-tailed t-test. (F) Immunohistochemistry data showing Yap1 expression in 14-dpf Tg(fabp10a:pt-β-catenin) livers treated with GW7647. Scale bars, 50 μm.

Suppression of YAP signaling promotes LPC-mediated liver regeneration, similar to PPARα activation. (A, B) qRT-PCR data showing the relative expression levels of hepatocyte (cyp7a1, gc, serpina1, ces2) and BEC (her9, epcam) markers and YAP target genes (ccn1, ccn2) between DMSO- and K-975-treated Tg(fabp10a:pt-β-catenin) livers at 14 dpf. (C) Section in situ hybridization images showing the expression of hepatocyte (cyp7a1, gc) and BEC (epcam) markers in K-975-treated Tg(fabp10a:pt-β-catenin) livers at 14 dpf. For quantification, larvae were grouped into +/− based on gene expression levels. Numbers in the upper right corner indicate the proportion of larvae exhibiting the phenotype shown. (D) Immunofluorescence images showing Bhmt expression in 13-dpf Tg(fabp10a:pt-β-catenin) livers treated with K-975. Based on the level of Bhmt expression, larvae were divided into three groups: +++/++/+. Data are represented as mean ± SD (A, B). ns not significant; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; statistical significance was calculated using an unpaired two-tailed t-test (A, B), Fisher’s exact test (C), and chi-square test (D). Dashed lines outline the livers (C, D). Scale bars, 50 μm.

PPARα activation promotes LPC-to-hepatocyte differentiation by suppressing YAP signaling. (A) Scheme illustrating an experimental strategy for YAP overactivation. The Tg(hs:cayap1) line was used to enhance YAP signaling with a heat-shock 6 h before GW7647 treatment. (B, C) qRT-PCR data showing the relative expression levels of hepatocyte (cyp7a1, gc, serpina1, ces2) and BEC (her9, epcam) markers and YAP target genes (ccn1, ccn2) among the following four groups of 14-dpf Tg(fabp10a:pt-β-catenin) livers: (1) DMSO-treated control, (2) cayap1⁺, (3) GW7647-treated, and (4) GW7647-treated cayap1⁺. Data are represented as mean ± SD. (D) Section in situ hybridization images showing the expression of hepatocyte (cyp7a1, gc) and BEC (epcam) markers in 14-dpf Tg(fabp10a:pt-β-catenin) livers. For quantification, larvae were grouped into ++/+/− based on gene expression levels. Dashed lines outline the livers. Numbers in the upper right corner indicate the proportion of larvae exhibiting the phenotype shown. Scale bars, 50 μm. (E) Violin plot graphs showing the quantification of the number of Abcb11⁺ canaliculi per liver area; median and quartiles are indicated by red dashed and black dotted lines, respectively. ns not significant; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001; statistical significance was calculated using an unpaired two-tailed t-test (B, C, E), Fisher’s exact test (D; cyp7a1), and chi-square test (D; gc).