TGF-β serves as a critical signaling determinant of liver progenitor cell activation and function
Chenhao Tong, Tao Lin, Han Wang, Luyao Jiang, Xiaodong Yuan, Wenwu Luo, Minghan Zhou, Carolina De La Torre, Hui Liu, Chen Shao, Seddik Hammad, Hui Gao, Jiarong Xie, Lei Xu, Roman Liebe, Zuguang Gu, Matthias P. Ebert, Huiguo Ding, Steven Dooley, Hong-Lei Weng
Chenhao Tong, Tao Lin, Han Wang, Luyao Jiang, Xiaodong Yuan, Wenwu Luo, Minghan Zhou, Carolina De La Torre, Hui Liu, Chen Shao, Seddik Hammad, Hui Gao, Jiarong Xie, Lei Xu, Roman Liebe, Zuguang Gu, Matthias P. Ebert, Huiguo Ding, Steven Dooley, Hong-Lei Weng
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Research Article Cell biology Hepatology

TGF-β serves as a critical signaling determinant of liver progenitor cell activation and function

Abstract

When massive hepatic necrosis–associated (MHN-associated) acute liver failure (ALF) occurs following severe damage, liver progenitor cells (LPCs) exit quiescence and enter differentiation programs during which they acquire hepatocyte-like functions. How LPCs maintain quiescence under physiological conditions and orchestrate activation following MHN remains largely unknown. We elucidate an essential role of TGF-β in regulating LPC quiescence and activation. Spatial transcriptomics and single-cell sequencing revealed that LPCs receive multiple signals, particularly TGF-β, HGF, and EGF, from surrounding hepatic stellate cells and macrophages in patients and zebrafish with MHN-induced ALF. Physiologically, TGF-β inhibits LPC proliferation by blocking G1-to-S phase transition, an effect reversed by Smad7 overexpression in a murine injury model. We observed extensive LPC proliferation in patients with ALF despite strong TGF-β/phosphorylated SMAD signaling. Immunostaining revealed concurrent activation of HGF/MET, EGF/EGFR, and downstream STAT3/ERK pathways in LPCs. In vitro, HGF or EGF overcame TGF-β–mediated growth arrest and promoted LPC proliferation. Beyond acting as a mitogen, HGF additionally induced hepatocyte gene programs (e.g., Hnf4a, Hnf1a) in LPCs. Strikingly, TGF-β signaling was required for HGF-dependent hepatocyte gene induction, indicating a dual role in restraining LPC proliferation and promoting functional maturation. These findings position TGF-β as a context-dependent determinant of LPC activation and lineage specification during ALF.

Authors

Chenhao Tong, Tao Lin, Han Wang, Luyao Jiang, Xiaodong Yuan, Wenwu Luo, Minghan Zhou, Carolina De La Torre, Hui Liu, Chen Shao, Seddik Hammad, Hui Gao, Jiarong Xie, Lei Xu, Roman Liebe, Zuguang Gu, Matthias P. Ebert, Huiguo Ding, Steven Dooley, Hong-Lei Weng

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Figure 3

ScRNA-seq reveals TGF-β and HGF signaling during cholangiocyte-to-hepatocyte differentiation following hepatocyte ablation in zebrafish.

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ScRNA-seq reveals TGF-β and HGF signaling during cholangiocyte-to-hepato...
(A and B) Uniform manifold approximation and projection (UMAP) clustering and cell cluster annotation — hepatocytes (HC), hepatic stellate cells (HSC), cholangiocytes (CC), and macrophages (MΦ) — based on scRNA-seq data from the livers of Mtz-treated Tg(fabp10a:CellCousin) zebrafish at control and 0, 1, and 9 dppa. (C) A dot plot illustrates the expression of representative genes in HC, HSC, CC, and MΦ. (D) Pseudotime trajectory analysis of CC reveals a branched differentiation path (top, colored by pseudotime; bottom, by group), with branch points labeled 1 and 2. Pie charts indicate the relative proportions of cells at corresponding pseudotime stages. (E) A heatmap shows dynamic expression of selected genes along the pseudotime trajectory. Genes are clustered into 4 clusters by expression patterns. (F) Pseudotime plots show the expression of selected genes along the trajectory. The black line indicates the overall trend in gene expression across pseudotime. (G) UMAP plots show the expression of tgfb1a, tgfb1b, tgfbr1b, hgfa, hgfb, and met in different cell clusters. (H) Pseudotime trajectory analysis of HSCs reveals a branched differentiation path (top, colored by pseudotime; bottom, by group), with branch points labeled 1, 2, and 3. (I) Pseudotime plots show the dynamic expression of hgfa, hgfb, tgfb1a, and tgfbr1b along pseudotime. (J) Network diagrams illustrate the directionality and intensity of TGF-β and HGF signaling among CC, HSC, MΦ, and HC. Line thickness indicates interaction strength, and arrow direction denotes the source-to-target relationship. (K) Dot plots display specific ligand-receptor (L-R) interactions in TGF-β and HGF signaling pathways between different cell populations.