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Dynamic endothelial cell rearrangements drive developmental vessel regression.

Franco CA, Jones ML, Bernabeu MO, Geudens I, Mathivet T, Rosa A, Lopes FM, Lima AP, Ragab A, Collins RT, Phng LK, Coveney PV, Gerhardt H - PLoS Biol. (2015)

Bottom Line: Patterning of functional blood vessel networks is achieved by pruning of superfluous connections.The cellular and molecular principles of vessel regression are poorly understood.Establishing and analyzing the first axial polarity map of all endothelial cells in a remodeling vascular network, we propose that balanced movement of cells maintains the primitive plexus under low shear conditions in a metastable dynamic state.

View Article: PubMed Central - PubMed

Affiliation: Vascular Biology Laboratory, London Research Institute-Cancer Research UK, Lincoln's Inn Laboratories, London, United Kingdom; Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal.

ABSTRACT
Patterning of functional blood vessel networks is achieved by pruning of superfluous connections. The cellular and molecular principles of vessel regression are poorly understood. Here we show that regression is mediated by dynamic and polarized migration of endothelial cells, representing anastomosis in reverse. Establishing and analyzing the first axial polarity map of all endothelial cells in a remodeling vascular network, we propose that balanced movement of cells maintains the primitive plexus under low shear conditions in a metastable dynamic state. We predict that flow-induced polarized migration of endothelial cells breaks symmetry and leads to stabilization of high flow/shear segments and regression of adjacent low flow/shear segments.

No MeSH data available.


Related in: MedlinePlus

Disorganized endothelial cell polarity correlates with vessel regression.A and B, Polarization of endothelial cells in a wild type (WT) P6 retina vascular network labeled for endothelial cell nuclei (Erg), basement membrane (Col.IV) lumen (intercellular adhesion molecule 2 [ICAM2]), and Golgi (130 kDa cis-Golgi matrix protein [GM130] or Golgi integral membrane protein 4 [Golph4]). Distance from the center of mass of each endothelial nucleus to the corresponding Golgi is used to draw a yellow (A) or pink (B) arrow, indicative of front–rear (axial) polarity. A, In anastomosis, endothelial polarities point towards each other. In regression, endothelial cells polarities point towards the neighboring vessel segments. Images were segmented for visualization purposes; original images can be found in S4 Fig B, Representative image of stochastic cell labeling using inducible Cre-lox mediated expression of membrane-bound GFP (mGFP), revealing the morphology of single endothelial cells in regressing vessels (white arrowhead) in combination with the axial polarity assessment (pink arrows). The white dotted line outlines one cell in a regression profile (lacking ICAM2), which is in contact with multiple vessel segments and shows an activated morphology with numerous filopodia. Scale bars (A and B: 10 μm).
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pbio.1002125.g003: Disorganized endothelial cell polarity correlates with vessel regression.A and B, Polarization of endothelial cells in a wild type (WT) P6 retina vascular network labeled for endothelial cell nuclei (Erg), basement membrane (Col.IV) lumen (intercellular adhesion molecule 2 [ICAM2]), and Golgi (130 kDa cis-Golgi matrix protein [GM130] or Golgi integral membrane protein 4 [Golph4]). Distance from the center of mass of each endothelial nucleus to the corresponding Golgi is used to draw a yellow (A) or pink (B) arrow, indicative of front–rear (axial) polarity. A, In anastomosis, endothelial polarities point towards each other. In regression, endothelial cells polarities point towards the neighboring vessel segments. Images were segmented for visualization purposes; original images can be found in S4 Fig B, Representative image of stochastic cell labeling using inducible Cre-lox mediated expression of membrane-bound GFP (mGFP), revealing the morphology of single endothelial cells in regressing vessels (white arrowhead) in combination with the axial polarity assessment (pink arrows). The white dotted line outlines one cell in a regression profile (lacking ICAM2), which is in contact with multiple vessel segments and shows an activated morphology with numerous filopodia. Scale bars (A and B: 10 μm).

Mentions: To gain a better understanding of directionality and coordination of cell movements, we investigated endothelial cell polarity along the axis of vessel segments in the remodeling plexus. In vitro, endothelial cells position their Golgi apparatus ahead of the nucleus in the direction of migration [14]. Using the endothelial-specific transcription factor Erg to label endothelial nuclei, the Golgi marker Golgi integral membrane protein 4 (Golph4) (Q8BXA1), together with lumen and Col.IV labeling, we determined endothelial cell nuclear shape and Golgi location in the mouse retina at P6 (Figs 3A and S3A). We established the distance between the center of mass of the endothelial nuclei and the position of the corresponding Golgi apparatus as a vector representing axial cell polarity (Fig 3A). Live imaging in transgenic zebrafish embryos confirmed the dynamic correlation between axial Golgi polarization and directional endothelial cell migration (S3 Movie). The Golgi apparatus of two anastomosing tip cells generally pointed towards the point of contact (Fig 3A), while in regressing vessels the Golgi position arrangements were reversed, suggesting that cells migrate away from each other during regression (Fig 3A and 3B). We therefore propose that regression in developing vascular plexuses is a cell migration–driven process, resembling the cellular events occurring during anastomosis in reverse order.


Dynamic endothelial cell rearrangements drive developmental vessel regression.

Franco CA, Jones ML, Bernabeu MO, Geudens I, Mathivet T, Rosa A, Lopes FM, Lima AP, Ragab A, Collins RT, Phng LK, Coveney PV, Gerhardt H - PLoS Biol. (2015)

Disorganized endothelial cell polarity correlates with vessel regression.A and B, Polarization of endothelial cells in a wild type (WT) P6 retina vascular network labeled for endothelial cell nuclei (Erg), basement membrane (Col.IV) lumen (intercellular adhesion molecule 2 [ICAM2]), and Golgi (130 kDa cis-Golgi matrix protein [GM130] or Golgi integral membrane protein 4 [Golph4]). Distance from the center of mass of each endothelial nucleus to the corresponding Golgi is used to draw a yellow (A) or pink (B) arrow, indicative of front–rear (axial) polarity. A, In anastomosis, endothelial polarities point towards each other. In regression, endothelial cells polarities point towards the neighboring vessel segments. Images were segmented for visualization purposes; original images can be found in S4 Fig B, Representative image of stochastic cell labeling using inducible Cre-lox mediated expression of membrane-bound GFP (mGFP), revealing the morphology of single endothelial cells in regressing vessels (white arrowhead) in combination with the axial polarity assessment (pink arrows). The white dotted line outlines one cell in a regression profile (lacking ICAM2), which is in contact with multiple vessel segments and shows an activated morphology with numerous filopodia. Scale bars (A and B: 10 μm).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4401640&req=5

pbio.1002125.g003: Disorganized endothelial cell polarity correlates with vessel regression.A and B, Polarization of endothelial cells in a wild type (WT) P6 retina vascular network labeled for endothelial cell nuclei (Erg), basement membrane (Col.IV) lumen (intercellular adhesion molecule 2 [ICAM2]), and Golgi (130 kDa cis-Golgi matrix protein [GM130] or Golgi integral membrane protein 4 [Golph4]). Distance from the center of mass of each endothelial nucleus to the corresponding Golgi is used to draw a yellow (A) or pink (B) arrow, indicative of front–rear (axial) polarity. A, In anastomosis, endothelial polarities point towards each other. In regression, endothelial cells polarities point towards the neighboring vessel segments. Images were segmented for visualization purposes; original images can be found in S4 Fig B, Representative image of stochastic cell labeling using inducible Cre-lox mediated expression of membrane-bound GFP (mGFP), revealing the morphology of single endothelial cells in regressing vessels (white arrowhead) in combination with the axial polarity assessment (pink arrows). The white dotted line outlines one cell in a regression profile (lacking ICAM2), which is in contact with multiple vessel segments and shows an activated morphology with numerous filopodia. Scale bars (A and B: 10 μm).
Mentions: To gain a better understanding of directionality and coordination of cell movements, we investigated endothelial cell polarity along the axis of vessel segments in the remodeling plexus. In vitro, endothelial cells position their Golgi apparatus ahead of the nucleus in the direction of migration [14]. Using the endothelial-specific transcription factor Erg to label endothelial nuclei, the Golgi marker Golgi integral membrane protein 4 (Golph4) (Q8BXA1), together with lumen and Col.IV labeling, we determined endothelial cell nuclear shape and Golgi location in the mouse retina at P6 (Figs 3A and S3A). We established the distance between the center of mass of the endothelial nuclei and the position of the corresponding Golgi apparatus as a vector representing axial cell polarity (Fig 3A). Live imaging in transgenic zebrafish embryos confirmed the dynamic correlation between axial Golgi polarization and directional endothelial cell migration (S3 Movie). The Golgi apparatus of two anastomosing tip cells generally pointed towards the point of contact (Fig 3A), while in regressing vessels the Golgi position arrangements were reversed, suggesting that cells migrate away from each other during regression (Fig 3A and 3B). We therefore propose that regression in developing vascular plexuses is a cell migration–driven process, resembling the cellular events occurring during anastomosis in reverse order.

Bottom Line: Patterning of functional blood vessel networks is achieved by pruning of superfluous connections.The cellular and molecular principles of vessel regression are poorly understood.Establishing and analyzing the first axial polarity map of all endothelial cells in a remodeling vascular network, we propose that balanced movement of cells maintains the primitive plexus under low shear conditions in a metastable dynamic state.

View Article: PubMed Central - PubMed

Affiliation: Vascular Biology Laboratory, London Research Institute-Cancer Research UK, Lincoln's Inn Laboratories, London, United Kingdom; Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal.

ABSTRACT
Patterning of functional blood vessel networks is achieved by pruning of superfluous connections. The cellular and molecular principles of vessel regression are poorly understood. Here we show that regression is mediated by dynamic and polarized migration of endothelial cells, representing anastomosis in reverse. Establishing and analyzing the first axial polarity map of all endothelial cells in a remodeling vascular network, we propose that balanced movement of cells maintains the primitive plexus under low shear conditions in a metastable dynamic state. We predict that flow-induced polarized migration of endothelial cells breaks symmetry and leads to stabilization of high flow/shear segments and regression of adjacent low flow/shear segments.

No MeSH data available.


Related in: MedlinePlus