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Digging deeper into lymphatic vessel formation in vitro and in vivo.

Detry B, Bruyère F, Erpicum C, Paupert J, Lamaye F, Maillard C, Lenoir B, Foidart JM, Thiry M, Noël A - BMC Cell Biol. (2011)

Bottom Line: Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection.Proliferating lymphatic endothelial cells were detected both at the tips of sprouting capillaries and inside extending sprouts.In this study, we are providing evidence for lymphatic vessel formation through tunneling relying on extensive matrix remodeling, migration and alignment of sprouting endothelial cells into tubular structures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Tumor and Development Biology, Groupe Interdisciplinaire de Génoprotéomique appliqué-Recherche (GIGA-Cancer), University of Liège, B-4000 Liège, Belgium.

ABSTRACT

Background: Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection. Lymphatic vasculature displays distinctive features than blood vasculature, and mechanisms underlying the formation of new lymphatic vessels during physiological and pathological processes are still poorly documented. Most studies on lymphatic vessel formation are focused on organism development rather than lymphangiogenic events occurring in adults. We have here studied lymphatic vessel formation in two in vivo models of pathological lymphangiogenesis (corneal assay and lymphangioma). These data have been confronted to those generated in the recently set up in vitro model of lymphatic ring assay. Ultrastructural analyses through Transmission Electron Microscopy (TEM) were performed to investigate tube morphogenesis, an important differentiating process observed during endothelial cell organization into capillary structures.

Results: In both in vivo models (lymphangiogenic corneal assay and lymphangioma), migrating lymphatic endothelial cells extended long processes exploring the neighboring environment and organized into cord-like structures. Signs of intense extracellular matrix remodeling were observed extracellularly and inside cytoplasmic vacuoles. The formation of intercellular spaces between endothelial cells led to tube formation. Proliferating lymphatic endothelial cells were detected both at the tips of sprouting capillaries and inside extending sprouts. The different steps of lymphangiogenesis observed in vivo are fully recapitulated in vitro, in the lymphatic ring assay and include: (1) endothelial cell alignment in cord like structure, (2) intracellular vacuole formation and (3) matrix degradation.

Conclusions: In this study, we are providing evidence for lymphatic vessel formation through tunneling relying on extensive matrix remodeling, migration and alignment of sprouting endothelial cells into tubular structures. In addition, our data emphasize the suitability of the lymphatic ring assay to unravel mechanisms underlying lymphangiogenesis.

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Related in: MedlinePlus

Vacuolization and lumen formation during lymphangiogenesis in vivo. Lymphangiogenesis was observed after thermal cauterization of the cornea (A, B) and in lymphangioma (C, D). (A): Prominent pinocytic activity (arrowhead) is visible along the plasma membrane and at cell junction. (B) Endothelial cells (en) containing intracellular vesicles are aligned and surrounded by matrix-free extracellular spaces (*). (C): Aligned elongated endothelial cells surrounded by extracellular spaces. Note the coalescence of intracellular vesicles (cv) and the presence of a blood vessel (bv) containing a white cell. (D) Vesicle coalescence (cv) into an intracellular luminal space is visible through a process similar to that depicted in B. bv = blood vessel; cv = coalescent vesicle; en: endothelial cell. Scale bars: 1 μm.
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Figure 4: Vacuolization and lumen formation during lymphangiogenesis in vivo. Lymphangiogenesis was observed after thermal cauterization of the cornea (A, B) and in lymphangioma (C, D). (A): Prominent pinocytic activity (arrowhead) is visible along the plasma membrane and at cell junction. (B) Endothelial cells (en) containing intracellular vesicles are aligned and surrounded by matrix-free extracellular spaces (*). (C): Aligned elongated endothelial cells surrounded by extracellular spaces. Note the coalescence of intracellular vesicles (cv) and the presence of a blood vessel (bv) containing a white cell. (D) Vesicle coalescence (cv) into an intracellular luminal space is visible through a process similar to that depicted in B. bv = blood vessel; cv = coalescent vesicle; en: endothelial cell. Scale bars: 1 μm.

Mentions: Migrating cells displayed numerous intracellular vacuoles of variable size, including in their cytoplasmic extension (Figure 3A, H and Figure 4A, B). The intracellular vacuoles fused to form a large intracellular luminal cavity (Figure 3I, Figure 4B, C, D). In addition, the establishment of intercellular spaces between LEC cords or LEC processes and the connection to and fusion with each other led to lumen formation (Figure 3D). Similar observations were made in both in vivo models.


Digging deeper into lymphatic vessel formation in vitro and in vivo.

Detry B, Bruyère F, Erpicum C, Paupert J, Lamaye F, Maillard C, Lenoir B, Foidart JM, Thiry M, Noël A - BMC Cell Biol. (2011)

Vacuolization and lumen formation during lymphangiogenesis in vivo. Lymphangiogenesis was observed after thermal cauterization of the cornea (A, B) and in lymphangioma (C, D). (A): Prominent pinocytic activity (arrowhead) is visible along the plasma membrane and at cell junction. (B) Endothelial cells (en) containing intracellular vesicles are aligned and surrounded by matrix-free extracellular spaces (*). (C): Aligned elongated endothelial cells surrounded by extracellular spaces. Note the coalescence of intracellular vesicles (cv) and the presence of a blood vessel (bv) containing a white cell. (D) Vesicle coalescence (cv) into an intracellular luminal space is visible through a process similar to that depicted in B. bv = blood vessel; cv = coalescent vesicle; en: endothelial cell. Scale bars: 1 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3141733&req=5

Figure 4: Vacuolization and lumen formation during lymphangiogenesis in vivo. Lymphangiogenesis was observed after thermal cauterization of the cornea (A, B) and in lymphangioma (C, D). (A): Prominent pinocytic activity (arrowhead) is visible along the plasma membrane and at cell junction. (B) Endothelial cells (en) containing intracellular vesicles are aligned and surrounded by matrix-free extracellular spaces (*). (C): Aligned elongated endothelial cells surrounded by extracellular spaces. Note the coalescence of intracellular vesicles (cv) and the presence of a blood vessel (bv) containing a white cell. (D) Vesicle coalescence (cv) into an intracellular luminal space is visible through a process similar to that depicted in B. bv = blood vessel; cv = coalescent vesicle; en: endothelial cell. Scale bars: 1 μm.
Mentions: Migrating cells displayed numerous intracellular vacuoles of variable size, including in their cytoplasmic extension (Figure 3A, H and Figure 4A, B). The intracellular vacuoles fused to form a large intracellular luminal cavity (Figure 3I, Figure 4B, C, D). In addition, the establishment of intercellular spaces between LEC cords or LEC processes and the connection to and fusion with each other led to lumen formation (Figure 3D). Similar observations were made in both in vivo models.

Bottom Line: Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection.Proliferating lymphatic endothelial cells were detected both at the tips of sprouting capillaries and inside extending sprouts.In this study, we are providing evidence for lymphatic vessel formation through tunneling relying on extensive matrix remodeling, migration and alignment of sprouting endothelial cells into tubular structures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Tumor and Development Biology, Groupe Interdisciplinaire de Génoprotéomique appliqué-Recherche (GIGA-Cancer), University of Liège, B-4000 Liège, Belgium.

ABSTRACT

Background: Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection. Lymphatic vasculature displays distinctive features than blood vasculature, and mechanisms underlying the formation of new lymphatic vessels during physiological and pathological processes are still poorly documented. Most studies on lymphatic vessel formation are focused on organism development rather than lymphangiogenic events occurring in adults. We have here studied lymphatic vessel formation in two in vivo models of pathological lymphangiogenesis (corneal assay and lymphangioma). These data have been confronted to those generated in the recently set up in vitro model of lymphatic ring assay. Ultrastructural analyses through Transmission Electron Microscopy (TEM) were performed to investigate tube morphogenesis, an important differentiating process observed during endothelial cell organization into capillary structures.

Results: In both in vivo models (lymphangiogenic corneal assay and lymphangioma), migrating lymphatic endothelial cells extended long processes exploring the neighboring environment and organized into cord-like structures. Signs of intense extracellular matrix remodeling were observed extracellularly and inside cytoplasmic vacuoles. The formation of intercellular spaces between endothelial cells led to tube formation. Proliferating lymphatic endothelial cells were detected both at the tips of sprouting capillaries and inside extending sprouts. The different steps of lymphangiogenesis observed in vivo are fully recapitulated in vitro, in the lymphatic ring assay and include: (1) endothelial cell alignment in cord like structure, (2) intracellular vacuole formation and (3) matrix degradation.

Conclusions: In this study, we are providing evidence for lymphatic vessel formation through tunneling relying on extensive matrix remodeling, migration and alignment of sprouting endothelial cells into tubular structures. In addition, our data emphasize the suitability of the lymphatic ring assay to unravel mechanisms underlying lymphangiogenesis.

Show MeSH
Related in: MedlinePlus