Limits...
Evidence for mesenchymal-epithelial transition associated with mouse hepatic stem cell differentiation.

Li B, Zheng YW, Sano Y, Taniguchi H - PLoS ONE (2011)

Bottom Line: However, the direct evidence of mesenchymal-epithelial transition associated with stem cells is unclear.The results of gene expression, immunohistochemistry and Western blot showed that as liver develops, the expression of epithelial markers such as Cytokeratin18 and E-cadherin increase, while expression of mesenchymal markers such as vimentin and N-cadherin decreased.On the other hand, in freshly isolated hepatic stem cells, the majority of cells (65.0%) co-express epithelial and mesenchymal markers; this proportion is significantly higher than observed in hematopoietic cells, non-hematopoietic cells and non-stem cell fractions.

View Article: PubMed Central - PubMed

Affiliation: Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan.

ABSTRACT

Unlabelled: Mesenchymal-epithelial transition events are related to embryonic development, tissue construction, and wound healing. Stem cells are involved in all of these processes, at least in part. However, the direct evidence of mesenchymal-epithelial transition associated with stem cells is unclear. To determine whether mesenchymal-epithelial transition occurs in liver development and/or the differentiation process of hepatic stem cells in vitro, we analyzed a variety of murine liver tissues from embryonic day 11.5 to adults and the colonies derived from hepatic stem/progenitor cells isolated with flow cytometry. The results of gene expression, immunohistochemistry and Western blot showed that as liver develops, the expression of epithelial markers such as Cytokeratin18 and E-cadherin increase, while expression of mesenchymal markers such as vimentin and N-cadherin decreased. On the other hand, in freshly isolated hepatic stem cells, the majority of cells (65.0%) co-express epithelial and mesenchymal markers; this proportion is significantly higher than observed in hematopoietic cells, non-hematopoietic cells and non-stem cell fractions. Likewise, in stem cell-derived colonies cultured over time, upregulation of epithelial genes (Cytokeratin-18 and E-cadherin) occurred simultaneously with downregulation of mesenchymal genes (vimentin and Snail1). Furthermore, in the fetal liver, vimentin-positive cells in the non-hematopoietic fraction had distinct proliferative activity and expressed early the hepatic lineage marker alpha-fetoprotein.

Conclusion: Hepatic stem cells co-express mesenchymal and epithelial markers; the mesenchymal-epithelial transition occurred in both liver development and differentiation of hepatic stem/progenitor cells in vitro. Besides as a mesenchymal marker, vimentin is a novel indicator for cell proliferative activity and undifferentiated status in liver cells.

Show MeSH
Mesenchymal−epithelial transition occurs in developing mouse liver.(A) Phenotype changes of liver cells according to development stages. Representative images showed hematoxylin/eosin staining of livers from C57BL/6J mice at E11.5, 13.5 and 17.5 and 8 weeks (Adult) after birth. Right panels showed the magnified pictures. (B) Immunofluorescence for simultaneous detection of CK8/18 (epithelial) and vimentin (mesenchymal); (C) E-cadherin (epithelial) and N-cadherin (mesenchymal) in livers from mice in (A). Arrows in (B) showed the CK8/18 and vimentin overlapping cells. (D) The ratio for CK8/18 and/or vimentin expressing non-hematopoietic liver cells from mice in indicated development stages. Quantitative analyses were based on immunofluorescence staining. These images showed gain of epithelial characters and loss of mesenchymal characters within mouse liver development. Vim: vimentin. E: embryonic day. BV: Blood vessel. PV: Portal vein. Scale bars = 100 µm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3037942&req=5

pone-0017092-g001: Mesenchymal−epithelial transition occurs in developing mouse liver.(A) Phenotype changes of liver cells according to development stages. Representative images showed hematoxylin/eosin staining of livers from C57BL/6J mice at E11.5, 13.5 and 17.5 and 8 weeks (Adult) after birth. Right panels showed the magnified pictures. (B) Immunofluorescence for simultaneous detection of CK8/18 (epithelial) and vimentin (mesenchymal); (C) E-cadherin (epithelial) and N-cadherin (mesenchymal) in livers from mice in (A). Arrows in (B) showed the CK8/18 and vimentin overlapping cells. (D) The ratio for CK8/18 and/or vimentin expressing non-hematopoietic liver cells from mice in indicated development stages. Quantitative analyses were based on immunofluorescence staining. These images showed gain of epithelial characters and loss of mesenchymal characters within mouse liver development. Vim: vimentin. E: embryonic day. BV: Blood vessel. PV: Portal vein. Scale bars = 100 µm.

Mentions: To investigate mesenchymal-epithelial transition in liver development, we analyzed the phenotype of cells and MET molecules in developing and adult mouse livers (Figure 1). ED11.5 liver cells are mesenchymal-like with lacking cell−cell connections (Figure 1A). As development proceeds, from ED11.5 to adult mouse, liver cells exhibited the change of cell shape from spindle to polygon, with larger size and tighter intercellular connections (Figure 1A). Moreover, an expansion of epithelial markers CK8/18 (Figure 1B and 1D; Table 1) and ZO-1 (Figure S1) but the reduction of vimentin through liver development were found (Figure 1B and 1D; Figure S1; Table 1). Similarly, an increasing of E-cadherin while decreasing of N-cadherin levels were observed (Figure 1C). N- and E-cadherin co-expressing cells were not found in adult liver (Figure 1C), demonstrating that not all the hepatocytes but cells around the central vein express N-cadherin, in consistent with the previous study [25]. Vimentin-positive cells in adult liver are only located near the portal vein, showing that blood vessel comprises these cells (Figure 1B; Figure S1). Statistically, in ED11.5 and ED13.5 liver, most non-hematopoietic cells are both epithelial and mesenchymal (CK8/18+vimentin+) (Figure 1B), at a rate of 68.3±16.3% and 37.0±29.8%, respectively (Figure 1D; Table 1), in contrast to those of 25.8±7.1% in ED17.5 and 6.0±3.2% in adult liver (Figure 1B and 1C; Table 1). These versatile results provide evidence that mesenchymal and epithelial co-expressing cells decreased with the development stages of mouse liver.


Evidence for mesenchymal-epithelial transition associated with mouse hepatic stem cell differentiation.

Li B, Zheng YW, Sano Y, Taniguchi H - PLoS ONE (2011)

Mesenchymal−epithelial transition occurs in developing mouse liver.(A) Phenotype changes of liver cells according to development stages. Representative images showed hematoxylin/eosin staining of livers from C57BL/6J mice at E11.5, 13.5 and 17.5 and 8 weeks (Adult) after birth. Right panels showed the magnified pictures. (B) Immunofluorescence for simultaneous detection of CK8/18 (epithelial) and vimentin (mesenchymal); (C) E-cadherin (epithelial) and N-cadherin (mesenchymal) in livers from mice in (A). Arrows in (B) showed the CK8/18 and vimentin overlapping cells. (D) The ratio for CK8/18 and/or vimentin expressing non-hematopoietic liver cells from mice in indicated development stages. Quantitative analyses were based on immunofluorescence staining. These images showed gain of epithelial characters and loss of mesenchymal characters within mouse liver development. Vim: vimentin. E: embryonic day. BV: Blood vessel. PV: Portal vein. Scale bars = 100 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037942&req=5

pone-0017092-g001: Mesenchymal−epithelial transition occurs in developing mouse liver.(A) Phenotype changes of liver cells according to development stages. Representative images showed hematoxylin/eosin staining of livers from C57BL/6J mice at E11.5, 13.5 and 17.5 and 8 weeks (Adult) after birth. Right panels showed the magnified pictures. (B) Immunofluorescence for simultaneous detection of CK8/18 (epithelial) and vimentin (mesenchymal); (C) E-cadherin (epithelial) and N-cadherin (mesenchymal) in livers from mice in (A). Arrows in (B) showed the CK8/18 and vimentin overlapping cells. (D) The ratio for CK8/18 and/or vimentin expressing non-hematopoietic liver cells from mice in indicated development stages. Quantitative analyses were based on immunofluorescence staining. These images showed gain of epithelial characters and loss of mesenchymal characters within mouse liver development. Vim: vimentin. E: embryonic day. BV: Blood vessel. PV: Portal vein. Scale bars = 100 µm.
Mentions: To investigate mesenchymal-epithelial transition in liver development, we analyzed the phenotype of cells and MET molecules in developing and adult mouse livers (Figure 1). ED11.5 liver cells are mesenchymal-like with lacking cell−cell connections (Figure 1A). As development proceeds, from ED11.5 to adult mouse, liver cells exhibited the change of cell shape from spindle to polygon, with larger size and tighter intercellular connections (Figure 1A). Moreover, an expansion of epithelial markers CK8/18 (Figure 1B and 1D; Table 1) and ZO-1 (Figure S1) but the reduction of vimentin through liver development were found (Figure 1B and 1D; Figure S1; Table 1). Similarly, an increasing of E-cadherin while decreasing of N-cadherin levels were observed (Figure 1C). N- and E-cadherin co-expressing cells were not found in adult liver (Figure 1C), demonstrating that not all the hepatocytes but cells around the central vein express N-cadherin, in consistent with the previous study [25]. Vimentin-positive cells in adult liver are only located near the portal vein, showing that blood vessel comprises these cells (Figure 1B; Figure S1). Statistically, in ED11.5 and ED13.5 liver, most non-hematopoietic cells are both epithelial and mesenchymal (CK8/18+vimentin+) (Figure 1B), at a rate of 68.3±16.3% and 37.0±29.8%, respectively (Figure 1D; Table 1), in contrast to those of 25.8±7.1% in ED17.5 and 6.0±3.2% in adult liver (Figure 1B and 1C; Table 1). These versatile results provide evidence that mesenchymal and epithelial co-expressing cells decreased with the development stages of mouse liver.

Bottom Line: However, the direct evidence of mesenchymal-epithelial transition associated with stem cells is unclear.The results of gene expression, immunohistochemistry and Western blot showed that as liver develops, the expression of epithelial markers such as Cytokeratin18 and E-cadherin increase, while expression of mesenchymal markers such as vimentin and N-cadherin decreased.On the other hand, in freshly isolated hepatic stem cells, the majority of cells (65.0%) co-express epithelial and mesenchymal markers; this proportion is significantly higher than observed in hematopoietic cells, non-hematopoietic cells and non-stem cell fractions.

View Article: PubMed Central - PubMed

Affiliation: Department of Regenerative Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan.

ABSTRACT

Unlabelled: Mesenchymal-epithelial transition events are related to embryonic development, tissue construction, and wound healing. Stem cells are involved in all of these processes, at least in part. However, the direct evidence of mesenchymal-epithelial transition associated with stem cells is unclear. To determine whether mesenchymal-epithelial transition occurs in liver development and/or the differentiation process of hepatic stem cells in vitro, we analyzed a variety of murine liver tissues from embryonic day 11.5 to adults and the colonies derived from hepatic stem/progenitor cells isolated with flow cytometry. The results of gene expression, immunohistochemistry and Western blot showed that as liver develops, the expression of epithelial markers such as Cytokeratin18 and E-cadherin increase, while expression of mesenchymal markers such as vimentin and N-cadherin decreased. On the other hand, in freshly isolated hepatic stem cells, the majority of cells (65.0%) co-express epithelial and mesenchymal markers; this proportion is significantly higher than observed in hematopoietic cells, non-hematopoietic cells and non-stem cell fractions. Likewise, in stem cell-derived colonies cultured over time, upregulation of epithelial genes (Cytokeratin-18 and E-cadherin) occurred simultaneously with downregulation of mesenchymal genes (vimentin and Snail1). Furthermore, in the fetal liver, vimentin-positive cells in the non-hematopoietic fraction had distinct proliferative activity and expressed early the hepatic lineage marker alpha-fetoprotein.

Conclusion: Hepatic stem cells co-express mesenchymal and epithelial markers; the mesenchymal-epithelial transition occurred in both liver development and differentiation of hepatic stem/progenitor cells in vitro. Besides as a mesenchymal marker, vimentin is a novel indicator for cell proliferative activity and undifferentiated status in liver cells.

Show MeSH