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Identification of a bipotential precursor cell in hepatic cell lines derived from transgenic mice expressing cyto-Met in the liver.

Spagnoli FM, Amicone L, Tripodi M, Weiss MC - J. Cell Biol. (1998)

Bottom Line: Palmate cells show none of these properties.Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells.The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development.

View Article: PubMed Central - PubMed

Affiliation: Unité de Génétique de la Différenciation, URA 1773 du Centre National de la Recherche Scientifique, Institut Pasteur, 75724 Paris Cedex 15, France.

ABSTRACT
Met murine hepatocyte (MMH) lines were established from livers of transgenic mice expressing constitutively active human Met. These lines harbor two cell types: epithelial cells resembling the parental populations and flattened cells with multiple projections and a dispersed growth habit that are designated palmate. Epithelial cells express the liver-enriched transcription factors HNF4 and HNF1alpha, and proteins associated with epithelial cell differentiation. Treatments that modulate their differentiation state, including acidic FGF, induce hepatic functions. Palmate cells show none of these properties. However, they can differentiate along the hepatic cell lineage, giving rise to: (a) epithelial cells that express hepatic transcription factors and are competent to express hepatic functions; (b) bile duct-like structures in three-dimensional Matrigel cultures. Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells. Furthermore, karyotype analysis confirms the direction of the phenotypic transition: palmate cells are diploid and the epithelial cells are hypotetraploid. The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development.

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Differences in the intrinsic  morphogenic activity of the epithelial  and the palmate clones are revealed by  culture on the three-dimensional matrix, Matrigel. Photographs taken from  10-d cultures on a thick layer of Matrigel. (A) Phase-contrast micrograph of  the spheroidal organization of the  epithelial clone; (B) palmate cells,  showing a spheroidal colony sending  out tubules. (C) composite of four  overlapping electron micrographs of a  thin section across a tubule of palmate  cells highlighting a duct-like structure  with a well-defined lumen and circumscribed by well-polarized cells with  junctional complexes and luminal  membranes covered with microvilli.  Bars: (B) 40 μm; (C) 5 μm.
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Figure 4: Differences in the intrinsic morphogenic activity of the epithelial and the palmate clones are revealed by culture on the three-dimensional matrix, Matrigel. Photographs taken from 10-d cultures on a thick layer of Matrigel. (A) Phase-contrast micrograph of the spheroidal organization of the epithelial clone; (B) palmate cells, showing a spheroidal colony sending out tubules. (C) composite of four overlapping electron micrographs of a thin section across a tubule of palmate cells highlighting a duct-like structure with a well-defined lumen and circumscribed by well-polarized cells with junctional complexes and luminal membranes covered with microvilli. Bars: (B) 40 μm; (C) 5 μm.

Mentions: Because cell–matrix interactions play an important role in establishing and maintaining the differentiated cell phenotype, the capacity of both clones to undergo morphogenesis on Matrigel (a commercial derivative of matrix extracted from the EHS mouse sarcoma) was evaluated. Growth of cells on this three-dimensional matrix for 7–10 d permitted the cells to sink into the gel. Under these conditions a striking difference in intrinsic morphogenic activity between the two classes of clones was revealed. Fig. 4 A illustrates the spheroidal three-dimensional organization consistently observed with cultures of epithelial clones. In contrast, the palmate clone gave rise to spheroidal structures that send out tubules (Fig. 4 B). Electron microscopic examination of a thin section of a tubule reveals that cells in Matrigel become polarized, showing stabilized cell–cell contacts and circumscribing lumina densely decorated with microvilli, resembling bile ducts (Fig. 4 C).


Identification of a bipotential precursor cell in hepatic cell lines derived from transgenic mice expressing cyto-Met in the liver.

Spagnoli FM, Amicone L, Tripodi M, Weiss MC - J. Cell Biol. (1998)

Differences in the intrinsic  morphogenic activity of the epithelial  and the palmate clones are revealed by  culture on the three-dimensional matrix, Matrigel. Photographs taken from  10-d cultures on a thick layer of Matrigel. (A) Phase-contrast micrograph of  the spheroidal organization of the  epithelial clone; (B) palmate cells,  showing a spheroidal colony sending  out tubules. (C) composite of four  overlapping electron micrographs of a  thin section across a tubule of palmate  cells highlighting a duct-like structure  with a well-defined lumen and circumscribed by well-polarized cells with  junctional complexes and luminal  membranes covered with microvilli.  Bars: (B) 40 μm; (C) 5 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132947&req=5

Figure 4: Differences in the intrinsic morphogenic activity of the epithelial and the palmate clones are revealed by culture on the three-dimensional matrix, Matrigel. Photographs taken from 10-d cultures on a thick layer of Matrigel. (A) Phase-contrast micrograph of the spheroidal organization of the epithelial clone; (B) palmate cells, showing a spheroidal colony sending out tubules. (C) composite of four overlapping electron micrographs of a thin section across a tubule of palmate cells highlighting a duct-like structure with a well-defined lumen and circumscribed by well-polarized cells with junctional complexes and luminal membranes covered with microvilli. Bars: (B) 40 μm; (C) 5 μm.
Mentions: Because cell–matrix interactions play an important role in establishing and maintaining the differentiated cell phenotype, the capacity of both clones to undergo morphogenesis on Matrigel (a commercial derivative of matrix extracted from the EHS mouse sarcoma) was evaluated. Growth of cells on this three-dimensional matrix for 7–10 d permitted the cells to sink into the gel. Under these conditions a striking difference in intrinsic morphogenic activity between the two classes of clones was revealed. Fig. 4 A illustrates the spheroidal three-dimensional organization consistently observed with cultures of epithelial clones. In contrast, the palmate clone gave rise to spheroidal structures that send out tubules (Fig. 4 B). Electron microscopic examination of a thin section of a tubule reveals that cells in Matrigel become polarized, showing stabilized cell–cell contacts and circumscribing lumina densely decorated with microvilli, resembling bile ducts (Fig. 4 C).

Bottom Line: Palmate cells show none of these properties.Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells.The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development.

View Article: PubMed Central - PubMed

Affiliation: Unité de Génétique de la Différenciation, URA 1773 du Centre National de la Recherche Scientifique, Institut Pasteur, 75724 Paris Cedex 15, France.

ABSTRACT
Met murine hepatocyte (MMH) lines were established from livers of transgenic mice expressing constitutively active human Met. These lines harbor two cell types: epithelial cells resembling the parental populations and flattened cells with multiple projections and a dispersed growth habit that are designated palmate. Epithelial cells express the liver-enriched transcription factors HNF4 and HNF1alpha, and proteins associated with epithelial cell differentiation. Treatments that modulate their differentiation state, including acidic FGF, induce hepatic functions. Palmate cells show none of these properties. However, they can differentiate along the hepatic cell lineage, giving rise to: (a) epithelial cells that express hepatic transcription factors and are competent to express hepatic functions; (b) bile duct-like structures in three-dimensional Matrigel cultures. Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells. Furthermore, karyotype analysis confirms the direction of the phenotypic transition: palmate cells are diploid and the epithelial cells are hypotetraploid. The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development.

Show MeSH