SOX9 contributes to the progression of ductular reaction for the protection from chronic liver injury.

The transcription factor sex-determining region Y-box 9 (SOX9) is a biliary epithelial marker ectopically expressed in hepatocytes (SOX9 + hepatocytes). SOX9 + hepatocytes are believed to function in ductular reaction (DR), recognized as an essential phenomenon related to liver regeneration; however, the functional role of SOX9 and clinical implications of SOX9 + hepatocytes in DR progression are unclear. Human and mouse liver samples were subjected to immunohistochemical and gene functional analyses to investigate the functional role of SOX9 and the clinical significance of SOX9 + hepatocytes.

Rapid repair of human disease-specific single-nucleotide variants by One-SHOT genome editing.

Many human diseases ranging from cancer to hereditary disorders are caused by single-nucleotide mutations in critical genes. Repairing these mutations would significantly improve the quality of life for patients with hereditary diseases. However, current procedures for repairing deleterious single-nucleotide mutations are not straightforward, requiring multiple steps and taking several months to complete.

New insight into reactive ductular cells of biliary atresia provided by pathological assessment of SOX9.

Background: Biliary atresia (BA) patients may survive until adolescence after effective Kasai procedure (KP). If liver fibrosis progresses even after successful KP, liver transplantation (LTx) is inevitable. Elucidation of its cause and pathophysiology would open the possibility of treating these patients by non-invasive management.

Multi-modal effects of BMP signaling on Nodal expression in the lateral plate mesoderm during left-right axis formation in the chick embryo.

During development of left-right asymmetry in the vertebrate embryo, Nodal plays a central role for determination of left-handedness. Bone morphogenetic protein (BMP) signaling has an important role for regulation of Nodal expression, although there is controversy over whether BMP signaling has a positive or negative effect on Nodal expression in the chick embryo. As BMP is a morphogen, we speculated that different concentrations might induce different responses in the cells of the lateral plate mesoderm (LPM).

BMP inhibition by DAN in Hensen's node is a critical step for the establishment of left-right asymmetry in the chick embryo.

During left-right (L-R) axis formation, Nodal is expressed in the node and has a central role in the transfer of L-R information in the vertebrate embryo. Bone morphogenetic protein (BMP) signaling also has an important role for maintenance of gene expression around the node. Several members of the Cerberus/Dan family act on L-R patterning by regulating activity of the transforming growth factor-β (TGF-β) family.

A secreted BMP antagonist, Cer1, fine tunes the spatial organization of the ureteric bud tree during mouse kidney development.

The epithelial ureteric bud is critical for mammalian kidney development as it generates the ureter and the collecting duct system that induces nephrogenesis in dicrete locations in the kidney mesenchyme during its emergence. We show that a secreted Bmp antagonist Cerberus homologue (Cer1) fine tunes the organization of the ureteric tree during organogenesis in the mouse embryo. Both enhanced ureteric expression of Cer1 and Cer1 knock out enlarge kidney size, and these changes are associated with an altered three-dimensional structure of the ureteric tree as revealed by optical projection tomography.

Ontogeny of angiopoietin-like protein 1, 2, 3, 4, 5, and 7 genes during chick embryonic development.

Angiopoietin-like proteins (ANGPTLs) are secreted proteins possessing an amino-terminal coiled-coil domain and a carboxyl-terminal fibrinogen-like domain and are known as angiogenic factors. Several members of ANGPTLs also regulate lipid metabolism independently of angiogenic effects, but most of their functions during vertebrate development are not demonstrated. To ascertain their developmental functions, we examined the expression patterns of Angptl1, 2, 3, 4, 5, and 7 orthologues during chick development using whole-mount in situ hybridization.

Defective development of the gall bladder and cystic duct in Lgr4- hypomorphic mice.

Leucine-rich repeat (LRR) -containing G protein coupled receptor (LGR) family members are characterized by the presence of a seven-transmembrane domain and LRR motifs. We describe a new function for Lgr4 in the development of the gall bladder and cystic duct and in the epithelium-mesenchyme interaction. Lgr4 expression was observed in the gall bladder epithelium when the gall bladder primordium elongated ventrally.

Wnt9a secreted from the walls of hepatic sinusoids is essential for morphogenesis, proliferation, and glycogen accumulation of chick hepatic epithelium.

Hepatic epithelial morphogenesis, including hepatoblast migration and proliferation in the septum transversum, requires the interaction of hepatic epithelium with the embryonic sinusoidal wall. No factors that mediate this interaction have yet been identified. As the beta-catenin pathway is active in hepatoblast proliferation, then Wnt ligands might activate the canonical Wnt pathway during liver development.

FGF signaling segregates biliary cell-lineage from chick hepatoblasts cooperatively with BMP4 and ECM components in vitro.

Intrahepatic bile ducts (IHBDs) are indispensable for transporting bile secreted from hepatocytes to the hepatic duct. The biliary epithelial cells (BECs) of the IHBD arise from bipotent hepatoblasts around the portal vein, suggesting the portal mesenchyme is essential for their development. However, except for Notch or Activin/TGF-beta signaling molecules, it is not known which molecules regulate IHBD development.

New primary culture systems to study the differentiation and proliferation of mouse fetal hepatoblasts.

Hepatoblasts have the potential to differentiate into both hepatocytes and biliary epithelial cells through a differentiation program that has not been fully elucidated. With the aim to better define the mechanism of differentiation of hepatoblasts, we isolated hepatoblasts and established new culture systems. We isolated hepatoblasts from E12.

Neurturin-GFRalpha2 signaling controls liver bud migration along the ductus venosus in the chick embryo.

During chick liver development, the liver bud arises from the foregut, invaginates into the septum transversum, and elongates along and envelops the ductus venosus. However, the mechanism of liver bud migration is only poorly understood. Here, we demonstrate that a GDNF family ligand involved in neuronal outgrowth and migration, neurturin (NRTN), and its receptor, GFRalpha2, are essential for liver bud migration.

Dan is required for normal morphogenesis and patterning in the developing chick inner ear.

During vertebrate inner ear development, compartmentalization of the auditory and vestibular apparatuses along two axes depends on the patterning of transcription factors expressed in a region-specific manner. Although most of the patterning is regulated by extrinsic signals, it is not known how Nkx5.1 and Msx1 are patterned.

Id3 is important for proliferation and differentiation of the hepatoblasts during the chick liver development.

The specified hepatic endoderm (hepatoblasts), the bipotential progenitor for hepatocytes and bile duct epithelial cells, proliferates during the primordial stages of liver development. Despite extensive studies, the mechanism that regulates proliferation of bipotential hepatoblasts is not fully understood. Here we show that Id3, a negative regulator of helix-loop-helix transcription factors, is an important regulator of hepatoblast proliferation in the developing chick liver.

Establishment of a chick embryo model for analyzing liver development and a search for candidate genes.

The liver plays a crucial role in metabolism. There is considerable interest in how the liver develops, as such knowledge could prove of importance in regenerative medicine. However, our understanding of liver development remains somewhat limited.

Analysis of gene expression patterns in the developing chick liver.

The chick embryo has been used widely for studying liver development. However, in the past 30 years, the usage has decreased markedly due to lack of appropriate marker genes for differentiation in the developing chick liver. To use the chick embryo for analyzing the molecular mechanism of liver development, we surveyed marker genes in the developing chick liver by examining the expression pattern of genes that are well-characterized in the developing mammalian liver.

Control of the Expression of AV-1 Protein, a Position-Specific Antigen, by ZPA (Zone of Polarizing Activity) Factor in the Chick Limb Bud: (Zone of polarizing activity/Position specific antigen/Limb pattern formation).

AV-1 protein is a molecule which shows position-specific expression during chick limb development, and is expected to have some important roles in limb pattern formation. In this study, to examine whether the ZPA (Zone of polarizing activity) effects the expression of the AV-1 protein, we have removed or grafted the ZPA in chick limb buds and observed AV-1 expression. Anterior halves of the limb buds which lack a ZPA were used as hosts.