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Endothelial alpha-parvin controls integrity of developing vasculature and is required for maintenance of cell-cell junctions.

Fraccaroli A, Pitter B, Taha AA, Seebach J, Huveneers S, Kirsch J, Casaroli-Marano RP, Zahler S, Pohl U, Gerhardt H, Schnittler HJ, Montanez E - Circ. Res. (2015)

Bottom Line: Angiogenesis and vessel integrity depend on the adhesion of endothelial cells (ECs) to the extracellular matrix and to adjacent ECs.Postnatal-induced EC-specific deletion of α-pv leads to retinal hypovascularization because of reduced vessel sprouting and excessive vessel regression.In vitro, α-pv-deficient ECs show reduced stable adherens junctions, decreased monolayer formation, and impaired motility, associated with reduced formation of integrin-mediated cell-extracellular matrix adhesion structures and an altered actin cytoskeleton.

View Article: PubMed Central - PubMed

Affiliation: From the Walter-Brendel-Centre of Experimental Medicine (A.F., B.P., J.K., U.P., E.M.) and Department of Pharmacy (S.Z.), Ludwig-Maximilians University Munich, Munich, Germany; Institute of Anatomy and Vascular Biology, WWU-Münster, Münster, Germany (A.A.T., J.S., H.-J.S.); Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Swammerdam Institute for Life Sciences, Amsterdam, The Netherlands (S.H.); Department of Surgery, School of Medicine and Hospital Clinic de Barcelona (IDIBAPS), University of Barcelona, Barcelona, Spain (R.P.C.-M.); and Vascular Biology Laboratory, London Research Institute-Cancer Research United Kingdom, London, United Kingdom (H.G.).

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Subcellular localization of α-parvin (α-pv) in endothelial cells (ECs). A, Double immunostaining of α-pv and VE-cadherin of human umbilical vein endothelial cells (HUVECs) cultured under sparse (a) and subconfluent (b–d) conditions on gelatin for 24 hours. Arrows point to VE-cadherin clusters and arrowheads indicate α-pv clusters. Dotted lines highlight the edge of small junction-associated intermittent lamellipodia. B, Triple-fluorescent labeling for α-pv, F-actin, and VE-cadherin of HUVECs. Notice that focal adhesions are linked to adherens junctions by F-actin cables (arrowheads).
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Figure 5: Subcellular localization of α-parvin (α-pv) in endothelial cells (ECs). A, Double immunostaining of α-pv and VE-cadherin of human umbilical vein endothelial cells (HUVECs) cultured under sparse (a) and subconfluent (b–d) conditions on gelatin for 24 hours. Arrows point to VE-cadherin clusters and arrowheads indicate α-pv clusters. Dotted lines highlight the edge of small junction-associated intermittent lamellipodia. B, Triple-fluorescent labeling for α-pv, F-actin, and VE-cadherin of HUVECs. Notice that focal adhesions are linked to adherens junctions by F-actin cables (arrowheads).

Mentions: To elucidate the mechanism by which α-pv regulates cell–cell junctions, we first investigated the subcellular localization of α-pv in HUVECs. Under sparse culture conditions, α-pv localized at FXs close to the edge of the lamellipodium (Online Figure VIIA; arrowheads) and at FAs at the tip of stress fibers (Online Figure VIIA; arrows). At sites where 2 adjacent cells overlap, α-pv also localized in small, punctate clusters that resemble FXs along the edge of the overlapping membranes (Figure 5A). Immunostaining revealed that initial VE-cadherin clusters localize between and in close proximity to α-pv clusters along the edge of these overlapping areas (Figure 5A). Similarly, α-pv was also distributed along the edge of JAIL at overlapping plasma membranes (Figure 5A; Online Figure VIIB; Online Movie I). Triple-fluorescence labeling for α-pv, VE-cadherin, and F-actin showed that α-pv dot-like structures at the cell–cell junctions are associated with the F-actin and occasionally connected via actin filaments to α-pv–positive FA-like structures (Figure 5B).


Endothelial alpha-parvin controls integrity of developing vasculature and is required for maintenance of cell-cell junctions.

Fraccaroli A, Pitter B, Taha AA, Seebach J, Huveneers S, Kirsch J, Casaroli-Marano RP, Zahler S, Pohl U, Gerhardt H, Schnittler HJ, Montanez E - Circ. Res. (2015)

Subcellular localization of α-parvin (α-pv) in endothelial cells (ECs). A, Double immunostaining of α-pv and VE-cadherin of human umbilical vein endothelial cells (HUVECs) cultured under sparse (a) and subconfluent (b–d) conditions on gelatin for 24 hours. Arrows point to VE-cadherin clusters and arrowheads indicate α-pv clusters. Dotted lines highlight the edge of small junction-associated intermittent lamellipodia. B, Triple-fluorescent labeling for α-pv, F-actin, and VE-cadherin of HUVECs. Notice that focal adhesions are linked to adherens junctions by F-actin cables (arrowheads).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470528&req=5

Figure 5: Subcellular localization of α-parvin (α-pv) in endothelial cells (ECs). A, Double immunostaining of α-pv and VE-cadherin of human umbilical vein endothelial cells (HUVECs) cultured under sparse (a) and subconfluent (b–d) conditions on gelatin for 24 hours. Arrows point to VE-cadherin clusters and arrowheads indicate α-pv clusters. Dotted lines highlight the edge of small junction-associated intermittent lamellipodia. B, Triple-fluorescent labeling for α-pv, F-actin, and VE-cadherin of HUVECs. Notice that focal adhesions are linked to adherens junctions by F-actin cables (arrowheads).
Mentions: To elucidate the mechanism by which α-pv regulates cell–cell junctions, we first investigated the subcellular localization of α-pv in HUVECs. Under sparse culture conditions, α-pv localized at FXs close to the edge of the lamellipodium (Online Figure VIIA; arrowheads) and at FAs at the tip of stress fibers (Online Figure VIIA; arrows). At sites where 2 adjacent cells overlap, α-pv also localized in small, punctate clusters that resemble FXs along the edge of the overlapping membranes (Figure 5A). Immunostaining revealed that initial VE-cadherin clusters localize between and in close proximity to α-pv clusters along the edge of these overlapping areas (Figure 5A). Similarly, α-pv was also distributed along the edge of JAIL at overlapping plasma membranes (Figure 5A; Online Figure VIIB; Online Movie I). Triple-fluorescence labeling for α-pv, VE-cadherin, and F-actin showed that α-pv dot-like structures at the cell–cell junctions are associated with the F-actin and occasionally connected via actin filaments to α-pv–positive FA-like structures (Figure 5B).

Bottom Line: Angiogenesis and vessel integrity depend on the adhesion of endothelial cells (ECs) to the extracellular matrix and to adjacent ECs.Postnatal-induced EC-specific deletion of α-pv leads to retinal hypovascularization because of reduced vessel sprouting and excessive vessel regression.In vitro, α-pv-deficient ECs show reduced stable adherens junctions, decreased monolayer formation, and impaired motility, associated with reduced formation of integrin-mediated cell-extracellular matrix adhesion structures and an altered actin cytoskeleton.

View Article: PubMed Central - PubMed

Affiliation: From the Walter-Brendel-Centre of Experimental Medicine (A.F., B.P., J.K., U.P., E.M.) and Department of Pharmacy (S.Z.), Ludwig-Maximilians University Munich, Munich, Germany; Institute of Anatomy and Vascular Biology, WWU-Münster, Münster, Germany (A.A.T., J.S., H.-J.S.); Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Swammerdam Institute for Life Sciences, Amsterdam, The Netherlands (S.H.); Department of Surgery, School of Medicine and Hospital Clinic de Barcelona (IDIBAPS), University of Barcelona, Barcelona, Spain (R.P.C.-M.); and Vascular Biology Laboratory, London Research Institute-Cancer Research United Kingdom, London, United Kingdom (H.G.).

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Related in: MedlinePlus