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A deficiency of uPAR alters endothelial angiogenic function and cell morphology.

Balsara RD, Merryman R, Virjee F, Northway C, Castellino FJ, Ploplis VA - (2011)

Bottom Line: This study focuses on the effect of uPAR deficiency (uPAR-/-) on angiogenic function and associated cytoskeletal organization.VEGF-enriched Matrigel implants from uPAR-/- mice demonstrated a lack of mature vessel formation compared to WT mice.Collectively, these results indicate that a uPAR deficiency leads to decreased angiogenic functions of endothelial cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: W, M, Keck Center for Transgene Research, University of Notre Dame, 230 Raclin-Carmichael Hall, Notre Dame, Indiana 46556, USA. vploplis@nd.edu.

ABSTRACT
The angiogenic potential of a cell requires dynamic reorganization of the cytoskeletal architecture that involves the interaction of urokinase-type plasminogen activator receptor (uPAR) with the extracellular matrix. This study focuses on the effect of uPAR deficiency (uPAR-/-) on angiogenic function and associated cytoskeletal organization. Utilizing murine endothelial cells, it was observed that adhesion, migration, proliferation, and capillary tube formation were altered in uPAR-/- cells compared to wild-type (WT) cells. On a vitronectin (Vn) matrix, uPAR-/- cells acquired a "fried egg" morphology characterized by circular actin organization and lack of lamellipodia formation. The up-regulation of β1 integrin, FAK(P-Tyr925), and paxillin (P-Tyr118), and decreased Rac1 activation, suggested increased focal adhesions, but delayed focal adhesion turnover in uPAR-/- cells. This accounted for the enhanced adhesion, but attenuated migration, on Vn. VEGF-enriched Matrigel implants from uPAR-/- mice demonstrated a lack of mature vessel formation compared to WT mice. Collectively, these results indicate that a uPAR deficiency leads to decreased angiogenic functions of endothelial cells.

No MeSH data available.


Related in: MedlinePlus

Effect of a uPAR deficiency on angiogenesis in an in vivo Matrigel assay: Matrigel containing 10 ng/ml VEGF was implanted s.c. and recovered on day 14 after implantation, fixed, and stained for smooth muscle α-actin to observe capillary formation. (A) Representative image of Matrigel implant excised from WT mouse shows the presence of robust and well-developed capillaries (arrows). (B) Representative image of Matrigel implant excised from uPAR-/- mouse shows the presence of several truncated structures that have not been organized to form a functional capillary (arrows).
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Figure 9: Effect of a uPAR deficiency on angiogenesis in an in vivo Matrigel assay: Matrigel containing 10 ng/ml VEGF was implanted s.c. and recovered on day 14 after implantation, fixed, and stained for smooth muscle α-actin to observe capillary formation. (A) Representative image of Matrigel implant excised from WT mouse shows the presence of robust and well-developed capillaries (arrows). (B) Representative image of Matrigel implant excised from uPAR-/- mouse shows the presence of several truncated structures that have not been organized to form a functional capillary (arrows).

Mentions: In order to further demonstrate that uPAR is required for promoting normal angiogenesis, an experimental model of in vivo blood vessel formation was performed. Matrigel matrix containing VEGF (10 ng/ml) was injected subcutaneously in WT and uPAR-/- mice and incubated for 14 days. The Matrigel plug was excised and stained for α-smooth muscle actin to detect formation of new blood vessels in the Matrigel implants. Immunofluorescence imaging revealed that implants from WT mice showed the presence of robustly formed capillaries, whereas implants from uPAR-/- mice contained several tiny punctate capillary-like vessels (Figure 9A,B). These results indicate that the absence of uPAR did not support normal vessel formation within the Matrigel plug which was further supported by in vitro observations demonstrating altered proliferation and migratory properties which would contribute to an inability of these cells to organize into functional blood vessels.


A deficiency of uPAR alters endothelial angiogenic function and cell morphology.

Balsara RD, Merryman R, Virjee F, Northway C, Castellino FJ, Ploplis VA - (2011)

Effect of a uPAR deficiency on angiogenesis in an in vivo Matrigel assay: Matrigel containing 10 ng/ml VEGF was implanted s.c. and recovered on day 14 after implantation, fixed, and stained for smooth muscle α-actin to observe capillary formation. (A) Representative image of Matrigel implant excised from WT mouse shows the presence of robust and well-developed capillaries (arrows). (B) Representative image of Matrigel implant excised from uPAR-/- mouse shows the presence of several truncated structures that have not been organized to form a functional capillary (arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105951&req=5

Figure 9: Effect of a uPAR deficiency on angiogenesis in an in vivo Matrigel assay: Matrigel containing 10 ng/ml VEGF was implanted s.c. and recovered on day 14 after implantation, fixed, and stained for smooth muscle α-actin to observe capillary formation. (A) Representative image of Matrigel implant excised from WT mouse shows the presence of robust and well-developed capillaries (arrows). (B) Representative image of Matrigel implant excised from uPAR-/- mouse shows the presence of several truncated structures that have not been organized to form a functional capillary (arrows).
Mentions: In order to further demonstrate that uPAR is required for promoting normal angiogenesis, an experimental model of in vivo blood vessel formation was performed. Matrigel matrix containing VEGF (10 ng/ml) was injected subcutaneously in WT and uPAR-/- mice and incubated for 14 days. The Matrigel plug was excised and stained for α-smooth muscle actin to detect formation of new blood vessels in the Matrigel implants. Immunofluorescence imaging revealed that implants from WT mice showed the presence of robustly formed capillaries, whereas implants from uPAR-/- mice contained several tiny punctate capillary-like vessels (Figure 9A,B). These results indicate that the absence of uPAR did not support normal vessel formation within the Matrigel plug which was further supported by in vitro observations demonstrating altered proliferation and migratory properties which would contribute to an inability of these cells to organize into functional blood vessels.

Bottom Line: This study focuses on the effect of uPAR deficiency (uPAR-/-) on angiogenic function and associated cytoskeletal organization.VEGF-enriched Matrigel implants from uPAR-/- mice demonstrated a lack of mature vessel formation compared to WT mice.Collectively, these results indicate that a uPAR deficiency leads to decreased angiogenic functions of endothelial cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: W, M, Keck Center for Transgene Research, University of Notre Dame, 230 Raclin-Carmichael Hall, Notre Dame, Indiana 46556, USA. vploplis@nd.edu.

ABSTRACT
The angiogenic potential of a cell requires dynamic reorganization of the cytoskeletal architecture that involves the interaction of urokinase-type plasminogen activator receptor (uPAR) with the extracellular matrix. This study focuses on the effect of uPAR deficiency (uPAR-/-) on angiogenic function and associated cytoskeletal organization. Utilizing murine endothelial cells, it was observed that adhesion, migration, proliferation, and capillary tube formation were altered in uPAR-/- cells compared to wild-type (WT) cells. On a vitronectin (Vn) matrix, uPAR-/- cells acquired a "fried egg" morphology characterized by circular actin organization and lack of lamellipodia formation. The up-regulation of β1 integrin, FAK(P-Tyr925), and paxillin (P-Tyr118), and decreased Rac1 activation, suggested increased focal adhesions, but delayed focal adhesion turnover in uPAR-/- cells. This accounted for the enhanced adhesion, but attenuated migration, on Vn. VEGF-enriched Matrigel implants from uPAR-/- mice demonstrated a lack of mature vessel formation compared to WT mice. Collectively, these results indicate that a uPAR deficiency leads to decreased angiogenic functions of endothelial cells.

No MeSH data available.


Related in: MedlinePlus