Liver is one of the largest internal organs in the body and its importance for metabolism, detoxification and homeostasis has been well established. In this review, we summarized recent progresses in studying liver in...Liver is one of the largest internal organs in the body and its importance for metabolism, detoxification and homeostasis has been well established. In this review, we summarized recent progresses in studying liver initiation and development during embryogenesis using zebrafish as a model system. We mainly focused on topics related to the specification of hepatoblasts from endoderm, the formation and growth of liver bud, the differentiation of hepatocytes and bile duct cells from hepatoblasts, and finally the role of mesodermal signals in controlling liver development in zebrafish.展开更多
Ribosome biogenesis in the nucleolus requires numerous nucleolar proteins and small non-coding RNAs.Among them is ribosome biogenesis factor Bmsl,which is highly conserved from yeast to human.In yeast,Bmsl initiates r...Ribosome biogenesis in the nucleolus requires numerous nucleolar proteins and small non-coding RNAs.Among them is ribosome biogenesis factor Bmsl,which is highly conserved from yeast to human.In yeast,Bmsl initiates ribosome biogenesis through recruiting Rcll to pre-ribosomes.However,little is known about the biological function of Bmsl in vertebrates.Here we report that Bmsl plays an essential role in zebrafish liver development.We identified a zebrafish bms1l^（sq163） mutant which carries a T to A mutation in the gene bmsl-like（bms1l）.This mutation results in L^（152） to Q^（152） substitution in a GTPase motif in Bmsll.Surprisingly,bmsll^（sq163） mutation confers hypoplasia specifically in the liver,exocrine pancreas and intestine after 3 days post-fertilization（dpf）.Consistent with the bmsll^（sq163） mutant phenotypes,whole-mount in situ hybridization（WISH） on wild type embryos showed that bmsll transcripts are abundant in the entire digestive tract and its accessory organs.Immunostaining for phospho-Histone 3（P-H3） and TUNEL assay revealed that impairment of hepatoblast proliferation rather than cell apoptosis is one of the consequences of bms1l（sq163） giving rise to an under-developed liver.Therefore,our findings demonstrate that Bmsll is necessary for zebrafish liver development.展开更多
Early studies utilized microarrays to identify liver-enriched genes,and the roles of some of these genes in liver development in mice and zebrafish were confirmed.1,2 However,many genes involved in liver growth regula...Early studies utilized microarrays to identify liver-enriched genes,and the roles of some of these genes in liver development in mice and zebrafish were confirmed.1,2 However,many genes involved in liver growth regulation remained unidentified through this approach.Recently,bulk RNA sequencing or single-cell RNA sequencing has been used to study liver differentiation,3 but no study has screened genes highly expressed in hepatocytes during liver growth.Since rapid hepatocyte proliferation is a common characteristic of liver growth in early liver development and hepatocellular carcinoma(HCC)progression,identifying the genes being involved in regulating liver growth and clarifying how it works would benefit studying HCC progress.展开更多
The liver is a key endoderm-derived multifunctional organ within the digestive system.Prospero homeobox 1(Prox1)is an essential transcription factor for liver development,but its specific function is not well understo...The liver is a key endoderm-derived multifunctional organ within the digestive system.Prospero homeobox 1(Prox1)is an essential transcription factor for liver development,but its specific function is not well understood.Here,we show that hepatic development,including the formation of intrahepatic biliary and vascular networks,is severely disrupted in prox1a mutant zebrafish.We find that Prox1a is essential for liver growth and proper differentiation but not required for early hepatic cell fate specification.Intriguingly,prox1a depletion leads to ectopic initiation of a Cdx1b-mediated intestinal program and the formation of intestinal lumen-like structures within the liver.Morpholino knockdown of cdx1b alleviates liver defects in the prox1a mutant zebrafish.Finally,chromatin immunoprecipitation analysis reveals that Prox1a binds directly to the promoter region of cdx1b,thereby repressing its expression.Overall,our findings indicate that Prox1a is required to promote and protect hepatic development by repression of Cdx1b-mediated intestinal cell fate in zebrafish.展开更多
Human stem cells are scalable cell populations capable of cellular differentiation.This makes them a very attractive in vitro cellular resource and in theory provides unlimited amounts of primary cells.Such an approac...Human stem cells are scalable cell populations capable of cellular differentiation.This makes them a very attractive in vitro cellular resource and in theory provides unlimited amounts of primary cells.Such an approach has the potential to improve our understanding of human biology and treating disease.In the future it may be possible to deploy novel stem cell-based approaches to treat human liver diseases.In recent years,eff icient hepatic differentiation from human stem cells has been achieved by several research groups including our own.In this review we provide an overview of the f ield and discuss the future potential and limitations of stem cell technology.展开更多
In mammals,the expression of the homeobox family member Cdx2/CDX2 is restricted within the intestine.Conditional ablation of the mouse Cdx2 in the endodermal cells causes a homeotic transformation of the intestine tow...In mammals,the expression of the homeobox family member Cdx2/CDX2 is restricted within the intestine.Conditional ablation of the mouse Cdx2 in the endodermal cells causes a homeotic transformation of the intestine towards the esophagus or gastric fate.In this report,we show that null mutants of zebrafish cdx1b,encoding the counterpart of mammalian CDX2,could survive more than 10 days post fertilization,a stage when the zebrafish digestive system has been well developed.Through RNA sequencing(RNA-seq)and single-cell sequencing(sc RNA-seq)of the dissected intestine from the mutant embryos,we demonstrate that the loss-of-function of the zebrafish cdx1b yields hepatocyte-like intestinal cells,a phenotype never observed in the mouse model.Further RNA-seq data analysis,and genetic double mutants and signaling inhibitor studies reveal that Cdx1b functions to guard the intestinal fate by repressing,directly or indirectly,a range of transcriptional factors and signaling pathways for liver specification.Finally,we demonstrate that heat shock-induced overexpression of cdx1b in a transgenic fish abolishes the liver formation.Therefore,we demonstrate that Cdx1b is a key repressor of hepatic fate during the intestine specification in zebrafish.展开更多
CYP2D6 expression in liver is age-dependent.Because epigenetic mechanisms,such as DNA methylation and histone modifications,modulate age-related gene expression during development,and are highly conserved among specie...CYP2D6 expression in liver is age-dependent.Because epigenetic mechanisms,such as DNA methylation and histone modifications,modulate age-related gene expression during development,and are highly conserved among species,the current study examined the epigenetic regulation of age-related expression of the Cyp2d genes in mouse liver.DNA methylation(DNAme),histone 3 lysine 4 dimethylation(H3K4me2),and histone 3 lysine 27 trimethylation(H3K27me3)was established by ChIP-on-chip tiling microarrays from mouse livers at prenatal,neonatal,and adult stages.Levels of DNAme,H3K4me2,and H3K27me3 were analyzed in a genomic region containing the Cyp2d clustering genes and their surrounding genes.Gradually increased expression levels of the Cyp2d9,Cyp2d10,Cyp2d22,and Cyp2d26 genes from prenatal,through neonatal,to adult are associated with gradually increased levels of H3K4me2 in the nucleosomes associated with these genes.Gene expression patterns during liver development in several Cyp2d surrounding genes,such as Srebf2,Sept3,Ndufa6,Tcf2,Nfam1,and Cyb5r3,could be also explained by changes of DNA methylation,H3K4me2,or H3K27me3 in those genes.In conclusion,the current study demonstrates that the changes of DNA methylation and histone modifications are associated with age-related expression patterns of the Cyp2d genes and their surrounding genes in liver cells during development.展开更多
基金supported by the National Natural Science Foundation of China (No. 30825025)
文摘Liver is one of the largest internal organs in the body and its importance for metabolism, detoxification and homeostasis has been well established. In this review, we summarized recent progresses in studying liver initiation and development during embryogenesis using zebrafish as a model system. We mainly focused on topics related to the specification of hepatoblasts from endoderm, the formation and growth of liver bud, the differentiation of hepatocytes and bile duct cells from hepatoblasts, and finally the role of mesodermal signals in controlling liver development in zebrafish.
基金supported by the grants from the National Natural Science Foundation of China(NSFC)(No.31171391) to LJLan NSFC grant(No. 30825025) to JRP and a grant from the National Research Foundation of Singapore(R-154-000-529-281) to YHH
文摘Ribosome biogenesis in the nucleolus requires numerous nucleolar proteins and small non-coding RNAs.Among them is ribosome biogenesis factor Bmsl,which is highly conserved from yeast to human.In yeast,Bmsl initiates ribosome biogenesis through recruiting Rcll to pre-ribosomes.However,little is known about the biological function of Bmsl in vertebrates.Here we report that Bmsl plays an essential role in zebrafish liver development.We identified a zebrafish bms1l^（sq163） mutant which carries a T to A mutation in the gene bmsl-like（bms1l）.This mutation results in L^（152） to Q^（152） substitution in a GTPase motif in Bmsll.Surprisingly,bmsll^（sq163） mutation confers hypoplasia specifically in the liver,exocrine pancreas and intestine after 3 days post-fertilization（dpf）.Consistent with the bmsll^（sq163） mutant phenotypes,whole-mount in situ hybridization（WISH） on wild type embryos showed that bmsll transcripts are abundant in the entire digestive tract and its accessory organs.Immunostaining for phospho-Histone 3（P-H3） and TUNEL assay revealed that impairment of hepatoblast proliferation rather than cell apoptosis is one of the consequences of bms1l（sq163） giving rise to an under-developed liver.Therefore,our findings demonstrate that Bmsll is necessary for zebrafish liver development.
基金supported by the National Natural Science Foundation of China(No.32070805)the Science and Technology Department of Sichuan Province,China(No.2024NSFSC2093)National Clinical Research Center for Child Health and Disorders,Children’s Hospital of Chongqing Medical University(NCRCCHD-2022-GP-04).
文摘Early studies utilized microarrays to identify liver-enriched genes,and the roles of some of these genes in liver development in mice and zebrafish were confirmed.1,2 However,many genes involved in liver growth regulation remained unidentified through this approach.Recently,bulk RNA sequencing or single-cell RNA sequencing has been used to study liver differentiation,3 but no study has screened genes highly expressed in hepatocytes during liver growth.Since rapid hepatocyte proliferation is a common characteristic of liver growth in early liver development and hepatocellular carcinoma(HCC)progression,identifying the genes being involved in regulating liver growth and clarifying how it works would benefit studying HCC progress.
基金partially supported by grants from the National Key Research and Development Program of China and the National Natural Science Foundation of China(2018YFA0801000,32270889,2019YFA0802800,32070824,2015CB942800,2016YFA0100500,31871458,31671500,and 81371264)supported by Beijing Natural Science Foundation(5242009)a grant from the Fisheries Innovation Team of Beijing Agriculture Innovation Consortium(BAIC07-2023-02).
文摘The liver is a key endoderm-derived multifunctional organ within the digestive system.Prospero homeobox 1(Prox1)is an essential transcription factor for liver development,but its specific function is not well understood.Here,we show that hepatic development,including the formation of intrahepatic biliary and vascular networks,is severely disrupted in prox1a mutant zebrafish.We find that Prox1a is essential for liver growth and proper differentiation but not required for early hepatic cell fate specification.Intriguingly,prox1a depletion leads to ectopic initiation of a Cdx1b-mediated intestinal program and the formation of intestinal lumen-like structures within the liver.Morpholino knockdown of cdx1b alleviates liver defects in the prox1a mutant zebrafish.Finally,chromatin immunoprecipitation analysis reveals that Prox1a binds directly to the promoter region of cdx1b,thereby repressing its expression.Overall,our findings indicate that Prox1a is required to promote and protect hepatic development by repression of Cdx1b-mediated intestinal cell fate in zebrafish.
基金Supported by A RCUK fellowship,EP/E500145/1,to Hay DCA grant from the Edinburgh Bioquarter,to Medine CNChina Scholarship Council,No.2010658022,to Zhou WL
文摘Human stem cells are scalable cell populations capable of cellular differentiation.This makes them a very attractive in vitro cellular resource and in theory provides unlimited amounts of primary cells.Such an approach has the potential to improve our understanding of human biology and treating disease.In the future it may be possible to deploy novel stem cell-based approaches to treat human liver diseases.In recent years,eff icient hepatic differentiation from human stem cells has been achieved by several research groups including our own.In this review we provide an overview of the f ield and discuss the future potential and limitations of stem cell technology.
基金supported by Centre for Computational Science and Engineering(CCSE)at Southern University of Science and Technologysupported by the National Key R&D Program of China(2018YFA0800502)the National Natural Science Foundation of China(31900579,31830113)。
文摘In mammals,the expression of the homeobox family member Cdx2/CDX2 is restricted within the intestine.Conditional ablation of the mouse Cdx2 in the endodermal cells causes a homeotic transformation of the intestine towards the esophagus or gastric fate.In this report,we show that null mutants of zebrafish cdx1b,encoding the counterpart of mammalian CDX2,could survive more than 10 days post fertilization,a stage when the zebrafish digestive system has been well developed.Through RNA sequencing(RNA-seq)and single-cell sequencing(sc RNA-seq)of the dissected intestine from the mutant embryos,we demonstrate that the loss-of-function of the zebrafish cdx1b yields hepatocyte-like intestinal cells,a phenotype never observed in the mouse model.Further RNA-seq data analysis,and genetic double mutants and signaling inhibitor studies reveal that Cdx1b functions to guard the intestinal fate by repressing,directly or indirectly,a range of transcriptional factors and signaling pathways for liver specification.Finally,we demonstrate that heat shock-induced overexpression of cdx1b in a transgenic fish abolishes the liver formation.Therefore,we demonstrate that Cdx1b is a key repressor of hepatic fate during the intestine specification in zebrafish.
基金supported by the National Institute of Health(1R01GM087376 and COBRE 5P20 RR021940).
文摘CYP2D6 expression in liver is age-dependent.Because epigenetic mechanisms,such as DNA methylation and histone modifications,modulate age-related gene expression during development,and are highly conserved among species,the current study examined the epigenetic regulation of age-related expression of the Cyp2d genes in mouse liver.DNA methylation(DNAme),histone 3 lysine 4 dimethylation(H3K4me2),and histone 3 lysine 27 trimethylation(H3K27me3)was established by ChIP-on-chip tiling microarrays from mouse livers at prenatal,neonatal,and adult stages.Levels of DNAme,H3K4me2,and H3K27me3 were analyzed in a genomic region containing the Cyp2d clustering genes and their surrounding genes.Gradually increased expression levels of the Cyp2d9,Cyp2d10,Cyp2d22,and Cyp2d26 genes from prenatal,through neonatal,to adult are associated with gradually increased levels of H3K4me2 in the nucleosomes associated with these genes.Gene expression patterns during liver development in several Cyp2d surrounding genes,such as Srebf2,Sept3,Ndufa6,Tcf2,Nfam1,and Cyb5r3,could be also explained by changes of DNA methylation,H3K4me2,or H3K27me3 in those genes.In conclusion,the current study demonstrates that the changes of DNA methylation and histone modifications are associated with age-related expression patterns of the Cyp2d genes and their surrounding genes in liver cells during development.
