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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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Loss of endothelial α-parvin (α-pv) results in increased vessel regression. A, P8 control and α-pviΔEC retinas labeled for isolectin-B4 (IB4) and collagen IV. Arrows point to empty collagen IV sleeves. B, Ratio of collagen IV–positive vessel segments to IB4-positive vessel segments. Values represent mean±SEM. P values are 0.18 and 0.0004, respectively. C, P7.5 control and α-pviΔEC retinas labeled for IB4 and cleaved (active) caspase-3. Arrows point to cleaved caspase-3–positive vessel segments. D, Relative ratio of cleaved (Act) caspase-3–positive vessel segments to total vessel segments. Values represent mean vs control±SEM. P value is 0.05. E, P7 control and α-pviΔEC retinas labeled for VE-cadherin. Arrow highlights intercellular space between endothelial cells (ECs). F, VE-cadherin whole-mount immunostaining of E15.5 yolk sacs from control and α-pvΔEC mice. Arrows highlight intercellular space between ECs. G, Quantification of intercellular space index in the YS vasculature. Values represent mean vs control±SEM. P value is 0.02. ns P>0.05, *P≤0.05, ***P≤0.001.
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Figure 3: Loss of endothelial α-parvin (α-pv) results in increased vessel regression. A, P8 control and α-pviΔEC retinas labeled for isolectin-B4 (IB4) and collagen IV. Arrows point to empty collagen IV sleeves. B, Ratio of collagen IV–positive vessel segments to IB4-positive vessel segments. Values represent mean±SEM. P values are 0.18 and 0.0004, respectively. C, P7.5 control and α-pviΔEC retinas labeled for IB4 and cleaved (active) caspase-3. Arrows point to cleaved caspase-3–positive vessel segments. D, Relative ratio of cleaved (Act) caspase-3–positive vessel segments to total vessel segments. Values represent mean vs control±SEM. P value is 0.05. E, P7 control and α-pviΔEC retinas labeled for VE-cadherin. Arrow highlights intercellular space between endothelial cells (ECs). F, VE-cadherin whole-mount immunostaining of E15.5 yolk sacs from control and α-pvΔEC mice. Arrows highlight intercellular space between ECs. G, Quantification of intercellular space index in the YS vasculature. Values represent mean vs control±SEM. P value is 0.02. ns P>0.05, *P≤0.05, ***P≤0.001.

Mentions: Because vessel instability results in reduced vessel density1 and regressing ECs leave empty basal membrane sleeves rich in collagen IV26, we determined whether depletion of α-pv from ECs impairs vessel stability by performing whole-mount immunostaining of control and α-pviΔEC retinas using an antibody against collagen IV and IB4. The analysis showed a significant increase in collagen IV segments lacking IB4 in α-pviΔEC retinas compared with control retinas, indicating that endothelial loss of α-pv indeed compromises vessel stability (Figure 3A and 3B). Furthermore, whole-mount immunostaining for cleaved caspase-3 and IB4 showed a significant increase in apoptotic vessel segments in α-pviΔEC retinas compared with control retinas (Figure 3C and 3D).


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)

Loss of endothelial α-parvin (α-pv) results in increased vessel regression. A, P8 control and α-pviΔEC retinas labeled for isolectin-B4 (IB4) and collagen IV. Arrows point to empty collagen IV sleeves. B, Ratio of collagen IV–positive vessel segments to IB4-positive vessel segments. Values represent mean±SEM. P values are 0.18 and 0.0004, respectively. C, P7.5 control and α-pviΔEC retinas labeled for IB4 and cleaved (active) caspase-3. Arrows point to cleaved caspase-3–positive vessel segments. D, Relative ratio of cleaved (Act) caspase-3–positive vessel segments to total vessel segments. Values represent mean vs control±SEM. P value is 0.05. E, P7 control and α-pviΔEC retinas labeled for VE-cadherin. Arrow highlights intercellular space between endothelial cells (ECs). F, VE-cadherin whole-mount immunostaining of E15.5 yolk sacs from control and α-pvΔEC mice. Arrows highlight intercellular space between ECs. G, Quantification of intercellular space index in the YS vasculature. Values represent mean vs control±SEM. P value is 0.02. ns P>0.05, *P≤0.05, ***P≤0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Loss of endothelial α-parvin (α-pv) results in increased vessel regression. A, P8 control and α-pviΔEC retinas labeled for isolectin-B4 (IB4) and collagen IV. Arrows point to empty collagen IV sleeves. B, Ratio of collagen IV–positive vessel segments to IB4-positive vessel segments. Values represent mean±SEM. P values are 0.18 and 0.0004, respectively. C, P7.5 control and α-pviΔEC retinas labeled for IB4 and cleaved (active) caspase-3. Arrows point to cleaved caspase-3–positive vessel segments. D, Relative ratio of cleaved (Act) caspase-3–positive vessel segments to total vessel segments. Values represent mean vs control±SEM. P value is 0.05. E, P7 control and α-pviΔEC retinas labeled for VE-cadherin. Arrow highlights intercellular space between endothelial cells (ECs). F, VE-cadherin whole-mount immunostaining of E15.5 yolk sacs from control and α-pvΔEC mice. Arrows highlight intercellular space between ECs. G, Quantification of intercellular space index in the YS vasculature. Values represent mean vs control±SEM. P value is 0.02. ns P>0.05, *P≤0.05, ***P≤0.001.
Mentions: Because vessel instability results in reduced vessel density1 and regressing ECs leave empty basal membrane sleeves rich in collagen IV26, we determined whether depletion of α-pv from ECs impairs vessel stability by performing whole-mount immunostaining of control and α-pviΔEC retinas using an antibody against collagen IV and IB4. The analysis showed a significant increase in collagen IV segments lacking IB4 in α-pviΔEC retinas compared with control retinas, indicating that endothelial loss of α-pv indeed compromises vessel stability (Figure 3A and 3B). Furthermore, whole-mount immunostaining for cleaved caspase-3 and IB4 showed a significant increase in apoptotic vessel segments in α-pviΔEC retinas compared with control retinas (Figure 3C and 3D).

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