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Proliferating mesodermal cells in murine embryos exhibiting macrophage and lymphendothelial characteristics.

Buttler K, Ezaki T, Wilting J - BMC Dev. Biol. (2008)

Bottom Line: Here, we have characterized the mesoderm of murine embryos with LEC markers Prox1, Lyve-1 and LA102 in combination with macrophage markers CD11b and F4/80.We observed cells co-expressing both types of markers (e.g. Prox1 - Lyve-1 - F4/80 triple-positive) located in the mesoderm, immediately adjacent to, and within lymph vessels.The impact of a dual source of LECs for ontogenetic, phylogenetic and pathological lymphangiogenesis is discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre of Anatomy, Department of Anatomy and Cell Biology, University Medicine Goettingen, Goettingen, Germany. buttler.kerstin@med.uni-goettingen.de

ABSTRACT

Background: The data on the embryonic origin of lymphatic endothelial cells (LECs) from either deep embryonic veins or mesenchymal (or circulating) lymphangioblasts presently available remain inconsistent. In various vertebrates, markers for LECs are first expressed in specific segments of embryonic veins arguing for a venous origin of lymph vessels. Very recently, studies on the mouse have strongly supported this view. However, in the chick, we have observed a dual origin of LECs from veins and from mesodermal lymphangioblasts. Additionally, in murine embryos we have detected mesenchymal cells that co-express LEC markers and the pan-leukocyte marker CD45. Here, we have characterized the mesoderm of murine embryos with LEC markers Prox1, Lyve-1 and LA102 in combination with macrophage markers CD11b and F4/80.

Results: We observed cells co-expressing both types of markers (e.g. Prox1 - Lyve-1 - F4/80 triple-positive) located in the mesoderm, immediately adjacent to, and within lymph vessels. Our proliferation studies with Ki-67 antibodies showed high proliferative capacities of both the Lyve-1-positive LECs of lymph sacs/lymphatic sprouts and the Lyve-1-positive mesenchymal cells.

Conclusion: Our data argue for a dual origin of LECs in the mouse, although the primary source of embryonic LECs may reside in specific embryonic veins and mesenchymal lymphangioblasts integrated secondarily into lymph vessels. The impact of a dual source of LECs for ontogenetic, phylogenetic and pathological lymphangiogenesis is discussed.

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Paraffin sections of mouse embryos stained with antibodies against Ki-67 (green) and Lyve-1 (red). Counter staining was performed with DAPI (blue). A) On ED 11.5, there are proliferating LECs in the developing jugular lymph sacs (jls) (arrows), but no double positive cells in the cardinal vein (v). B) Two mesenchymal cells positive for the markers located in the dermatome (arrows). g, spinal ganglion. C) JLS of ED 12.5 mice with LECs (arrows) expressing Ki-67 and Lyve-1. D) Sprout from the JLS containing proliferating cells (arrows). Inset: Higher magnification showing Ki-67-positive (arrow) and negative (arrowhead) LECs.
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Figure 6: Paraffin sections of mouse embryos stained with antibodies against Ki-67 (green) and Lyve-1 (red). Counter staining was performed with DAPI (blue). A) On ED 11.5, there are proliferating LECs in the developing jugular lymph sacs (jls) (arrows), but no double positive cells in the cardinal vein (v). B) Two mesenchymal cells positive for the markers located in the dermatome (arrows). g, spinal ganglion. C) JLS of ED 12.5 mice with LECs (arrows) expressing Ki-67 and Lyve-1. D) Sprout from the JLS containing proliferating cells (arrows). Inset: Higher magnification showing Ki-67-positive (arrow) and negative (arrowhead) LECs.

Mentions: Ki-67 is a well-established proliferation marker and is increasingly expressed in the nucleus in all active phases of the cell cycle, but not in G0 phase [31]. To extend our studies on the source of LECs, we performed double staining with anti-Ki-67 and anti-Lyve-1 antibodies of ED 11.5 – 13.5 mice. Nuclei were counter stained with 4',6-diamidino-2-phenylindol (DAPI). Double positive LECs could be detected in regions of active lymphangiogenesis: the early jugular veins, the jugular lymph sacs, which extended sprouts into dorso-lateral directions, the mediastinum and the dermis (Fig. 6). Mouse embryos on ED 11.5 exhibited very few cells in the cardinal veins positive for both markers, whereas LECs of the developing jugular lymph sacs as well as mesenchymal cells in the dermis co-expressed Ki-67 and Lyve-1 at high rates (Fig. 6A,B). The dermatomes of ED 12.5 and 13.5 mice displayed scattered Lyve-1+ cells, which also showed proliferating characteristics (55% and 33%, respectively; Fig. 7). However, the total number of Lyve-1+ cells in the dermatomes was low compared with the number of lymph sac ECs. In the jugular lymph sacs (Fig. 6C) and in sprouts derived from them (Fig. 6D) the Ki-67 labelling rate was 22 – 30% (Fig. 7). The data show that a greater number of Lyve-1+ cells are present in the lymph sacs than in the dermatomes, but the latter proliferate at equal or, in ED 12.5 embryos, even higher rates.


Proliferating mesodermal cells in murine embryos exhibiting macrophage and lymphendothelial characteristics.

Buttler K, Ezaki T, Wilting J - BMC Dev. Biol. (2008)

Paraffin sections of mouse embryos stained with antibodies against Ki-67 (green) and Lyve-1 (red). Counter staining was performed with DAPI (blue). A) On ED 11.5, there are proliferating LECs in the developing jugular lymph sacs (jls) (arrows), but no double positive cells in the cardinal vein (v). B) Two mesenchymal cells positive for the markers located in the dermatome (arrows). g, spinal ganglion. C) JLS of ED 12.5 mice with LECs (arrows) expressing Ki-67 and Lyve-1. D) Sprout from the JLS containing proliferating cells (arrows). Inset: Higher magnification showing Ki-67-positive (arrow) and negative (arrowhead) LECs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2375885&req=5

Figure 6: Paraffin sections of mouse embryos stained with antibodies against Ki-67 (green) and Lyve-1 (red). Counter staining was performed with DAPI (blue). A) On ED 11.5, there are proliferating LECs in the developing jugular lymph sacs (jls) (arrows), but no double positive cells in the cardinal vein (v). B) Two mesenchymal cells positive for the markers located in the dermatome (arrows). g, spinal ganglion. C) JLS of ED 12.5 mice with LECs (arrows) expressing Ki-67 and Lyve-1. D) Sprout from the JLS containing proliferating cells (arrows). Inset: Higher magnification showing Ki-67-positive (arrow) and negative (arrowhead) LECs.
Mentions: Ki-67 is a well-established proliferation marker and is increasingly expressed in the nucleus in all active phases of the cell cycle, but not in G0 phase [31]. To extend our studies on the source of LECs, we performed double staining with anti-Ki-67 and anti-Lyve-1 antibodies of ED 11.5 – 13.5 mice. Nuclei were counter stained with 4',6-diamidino-2-phenylindol (DAPI). Double positive LECs could be detected in regions of active lymphangiogenesis: the early jugular veins, the jugular lymph sacs, which extended sprouts into dorso-lateral directions, the mediastinum and the dermis (Fig. 6). Mouse embryos on ED 11.5 exhibited very few cells in the cardinal veins positive for both markers, whereas LECs of the developing jugular lymph sacs as well as mesenchymal cells in the dermis co-expressed Ki-67 and Lyve-1 at high rates (Fig. 6A,B). The dermatomes of ED 12.5 and 13.5 mice displayed scattered Lyve-1+ cells, which also showed proliferating characteristics (55% and 33%, respectively; Fig. 7). However, the total number of Lyve-1+ cells in the dermatomes was low compared with the number of lymph sac ECs. In the jugular lymph sacs (Fig. 6C) and in sprouts derived from them (Fig. 6D) the Ki-67 labelling rate was 22 – 30% (Fig. 7). The data show that a greater number of Lyve-1+ cells are present in the lymph sacs than in the dermatomes, but the latter proliferate at equal or, in ED 12.5 embryos, even higher rates.

Bottom Line: Here, we have characterized the mesoderm of murine embryos with LEC markers Prox1, Lyve-1 and LA102 in combination with macrophage markers CD11b and F4/80.We observed cells co-expressing both types of markers (e.g. Prox1 - Lyve-1 - F4/80 triple-positive) located in the mesoderm, immediately adjacent to, and within lymph vessels.The impact of a dual source of LECs for ontogenetic, phylogenetic and pathological lymphangiogenesis is discussed.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre of Anatomy, Department of Anatomy and Cell Biology, University Medicine Goettingen, Goettingen, Germany. buttler.kerstin@med.uni-goettingen.de

ABSTRACT

Background: The data on the embryonic origin of lymphatic endothelial cells (LECs) from either deep embryonic veins or mesenchymal (or circulating) lymphangioblasts presently available remain inconsistent. In various vertebrates, markers for LECs are first expressed in specific segments of embryonic veins arguing for a venous origin of lymph vessels. Very recently, studies on the mouse have strongly supported this view. However, in the chick, we have observed a dual origin of LECs from veins and from mesodermal lymphangioblasts. Additionally, in murine embryos we have detected mesenchymal cells that co-express LEC markers and the pan-leukocyte marker CD45. Here, we have characterized the mesoderm of murine embryos with LEC markers Prox1, Lyve-1 and LA102 in combination with macrophage markers CD11b and F4/80.

Results: We observed cells co-expressing both types of markers (e.g. Prox1 - Lyve-1 - F4/80 triple-positive) located in the mesoderm, immediately adjacent to, and within lymph vessels. Our proliferation studies with Ki-67 antibodies showed high proliferative capacities of both the Lyve-1-positive LECs of lymph sacs/lymphatic sprouts and the Lyve-1-positive mesenchymal cells.

Conclusion: Our data argue for a dual origin of LECs in the mouse, although the primary source of embryonic LECs may reside in specific embryonic veins and mesenchymal lymphangioblasts integrated secondarily into lymph vessels. The impact of a dual source of LECs for ontogenetic, phylogenetic and pathological lymphangiogenesis is discussed.

Show MeSH
Related in: MedlinePlus