Limits...
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

Actin cytoskeleton organization is circular in uPAR-/- ECs: Lack of uPAR expression induces changes in cell morphology and actin cytoskeleton. Quiescent WT (A, C) and uPAR-/- (B, D) ECs were plated on Vn and allowed to adhere for 4 hr and then stained for actin with phalloidin-FITC. Cells stained for actin (green) and the nucleus (blue) were imaged using a confocal microscope. Images obtained using a 30× objective (A, B) revealed morphological differences between WT and uPAR-/- ECs. Images at higher magnification (100× objective) (C, D) demonstrated that while the WT cells showed polarized actin formation, the uPAR-/- ECs maintained an atypical concentric actin organization.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3105951&req=5

Figure 4: Actin cytoskeleton organization is circular in uPAR-/- ECs: Lack of uPAR expression induces changes in cell morphology and actin cytoskeleton. Quiescent WT (A, C) and uPAR-/- (B, D) ECs were plated on Vn and allowed to adhere for 4 hr and then stained for actin with phalloidin-FITC. Cells stained for actin (green) and the nucleus (blue) were imaged using a confocal microscope. Images obtained using a 30× objective (A, B) revealed morphological differences between WT and uPAR-/- ECs. Images at higher magnification (100× objective) (C, D) demonstrated that while the WT cells showed polarized actin formation, the uPAR-/- ECs maintained an atypical concentric actin organization.

Mentions: Our data demonstrated that uPAR-/- cells had stronger adhesive properties with concomitant decreased migratory and proliferative abilities when plated on Vn compared to WT cells. Since cell morphology on the ECM is a critical parameter for determining cell growth and apoptosis, the actin organization of uPAR-/- and WT ECs was analyzed when cultured on both Vn and collagen. Immunofluorescence studies revealed that the uPAR-/- ECs showed typical "fried egg" morphology with a lack of actin polarization and lamellipodia formation when plated on Vn compared to WT cells (Figure 4A,B). WT cells showed the expected elongated cell shape with polarized actin and several lamellipodia extensions (Figure 4A,C). The actin architecture in uPAR-/- ECs was observed as a circular network of filaments around the nucleus with radial filaments ending towards the edges of the plasma membrane (Figure 4B,D). uPAR-/- cells grown on collagen did not exhibit the "fried egg" morphology and were morphologically similar to WT cells (data not shown).


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

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

Actin cytoskeleton organization is circular in uPAR-/- ECs: Lack of uPAR expression induces changes in cell morphology and actin cytoskeleton. Quiescent WT (A, C) and uPAR-/- (B, D) ECs were plated on Vn and allowed to adhere for 4 hr and then stained for actin with phalloidin-FITC. Cells stained for actin (green) and the nucleus (blue) were imaged using a confocal microscope. Images obtained using a 30× objective (A, B) revealed morphological differences between WT and uPAR-/- ECs. Images at higher magnification (100× objective) (C, D) demonstrated that while the WT cells showed polarized actin formation, the uPAR-/- ECs maintained an atypical concentric actin organization.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Actin cytoskeleton organization is circular in uPAR-/- ECs: Lack of uPAR expression induces changes in cell morphology and actin cytoskeleton. Quiescent WT (A, C) and uPAR-/- (B, D) ECs were plated on Vn and allowed to adhere for 4 hr and then stained for actin with phalloidin-FITC. Cells stained for actin (green) and the nucleus (blue) were imaged using a confocal microscope. Images obtained using a 30× objective (A, B) revealed morphological differences between WT and uPAR-/- ECs. Images at higher magnification (100× objective) (C, D) demonstrated that while the WT cells showed polarized actin formation, the uPAR-/- ECs maintained an atypical concentric actin organization.
Mentions: Our data demonstrated that uPAR-/- cells had stronger adhesive properties with concomitant decreased migratory and proliferative abilities when plated on Vn compared to WT cells. Since cell morphology on the ECM is a critical parameter for determining cell growth and apoptosis, the actin organization of uPAR-/- and WT ECs was analyzed when cultured on both Vn and collagen. Immunofluorescence studies revealed that the uPAR-/- ECs showed typical "fried egg" morphology with a lack of actin polarization and lamellipodia formation when plated on Vn compared to WT cells (Figure 4A,B). WT cells showed the expected elongated cell shape with polarized actin and several lamellipodia extensions (Figure 4A,C). The actin architecture in uPAR-/- ECs was observed as a circular network of filaments around the nucleus with radial filaments ending towards the edges of the plasma membrane (Figure 4B,D). uPAR-/- cells grown on collagen did not exhibit the "fried egg" morphology and were morphologically similar to WT cells (data not shown).

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