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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

Tubulogenesis is impaired in uPAR-/- ECs: Bead-based fibrin gel angiogenesis was observed at 96 hr and the cells were stained for actin using phalloidin-TRITC (red) and DNA (blue) and imaged using a 20× objective. Formation of capillary-like structures at 96 hr in WT cells in control (A) assay and in the presence of 10 ng/ml VEGF was observed (C). In beads plated with uPAR-/- ECs, highly branched sprouts were observed but were not organized to form capillary-like structures in the absence or presence of VEGF (B, D).
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Figure 8: Tubulogenesis is impaired in uPAR-/- ECs: Bead-based fibrin gel angiogenesis was observed at 96 hr and the cells were stained for actin using phalloidin-TRITC (red) and DNA (blue) and imaged using a 20× objective. Formation of capillary-like structures at 96 hr in WT cells in control (A) assay and in the presence of 10 ng/ml VEGF was observed (C). In beads plated with uPAR-/- ECs, highly branched sprouts were observed but were not organized to form capillary-like structures in the absence or presence of VEGF (B, D).

Mentions: After 96 hr it was observed that WT ECs were able to organize into lumen-containing capillary-like structures (Figure 8A,C). However, uPAR-/- cells were unable to orchestrate tubulogenesis, and lumen formation was scarce and irregular in shape (Figure 8B,D). The uPAR-/- ECs appeared to grow longer sprouts that are highly branched and that could contact another vessel, but were unable to undergo normal anastomosis and form lumen-like structures, as was the case with WT cells. Thus, it is concluded that depletion of uPAR in angiogenically functional ECs disrupts cell migration, proliferation, adhesion, and anastomosis, events that are crucial for new blood vessel growth in vivo.


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

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

Tubulogenesis is impaired in uPAR-/- ECs: Bead-based fibrin gel angiogenesis was observed at 96 hr and the cells were stained for actin using phalloidin-TRITC (red) and DNA (blue) and imaged using a 20× objective. Formation of capillary-like structures at 96 hr in WT cells in control (A) assay and in the presence of 10 ng/ml VEGF was observed (C). In beads plated with uPAR-/- ECs, highly branched sprouts were observed but were not organized to form capillary-like structures in the absence or presence of VEGF (B, D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 8: Tubulogenesis is impaired in uPAR-/- ECs: Bead-based fibrin gel angiogenesis was observed at 96 hr and the cells were stained for actin using phalloidin-TRITC (red) and DNA (blue) and imaged using a 20× objective. Formation of capillary-like structures at 96 hr in WT cells in control (A) assay and in the presence of 10 ng/ml VEGF was observed (C). In beads plated with uPAR-/- ECs, highly branched sprouts were observed but were not organized to form capillary-like structures in the absence or presence of VEGF (B, D).
Mentions: After 96 hr it was observed that WT ECs were able to organize into lumen-containing capillary-like structures (Figure 8A,C). However, uPAR-/- cells were unable to orchestrate tubulogenesis, and lumen formation was scarce and irregular in shape (Figure 8B,D). The uPAR-/- ECs appeared to grow longer sprouts that are highly branched and that could contact another vessel, but were unable to undergo normal anastomosis and form lumen-like structures, as was the case with WT cells. Thus, it is concluded that depletion of uPAR in angiogenically functional ECs disrupts cell migration, proliferation, adhesion, and anastomosis, events that are crucial for new blood vessel growth in vivo.

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